Journal of the Society of Telegraph Engineers - Forgotten Books

_ a — Q

JOUR NAL

OF THE

SOCIETY OFTELEGRAPH ENGINEERS,

INCLUDING

ORIGINAL COMMUNICATIONS ON TELEGRAPHY AND

ELECTR ICAL SCIENCE.

PUBLISHED UNDER THE“

SUPERVISION OF THE EDITING

AND EDITED BY

L IEUT .-C

‘0L . FRANK BOLTON , C .E HON . SECRETARY,

AND

WILLIAM EDWARD LANGDON , ACTING SECRETARY.

V OL . V .- 1 8 7 6 . J

lonhon

E. AN D F. N . S PON , 4 8, CHA R I NG C R O S S.

N ew y ork:

446, BROOME STREET.

TABLE OF CONTENTS.

V OL . V .

Pro ce edings o f M ee ting he ld o n W edn e sday, 12 January, 1876Pre siden t

’s Inaugural Addre ss

Proceedings o f M eeting h e ld on W edn e sday, 26 January, 1876Discussio n o n Mr. Flee tw oo d’

s Pape r On Un derground Te legraphs— TheLo n do n Stree t System

Pro ce edings o f Me e ting h e ld o n W edn esday, 9 February, 1876Pape r On Co n tributio ns to the Th e o ry o f Submerging and Testing

Un dergro un d Te legraphs,” by Dr. W ern er Siemens

Discussion o n th e abo ve

Pro ceedings o f Mee ting h e ld o n W edn esday , 23 February, 1876Adjo urn ed D iscussio n o n Dr. W ern er Siemen s’ Paper

Proceedings o fMe eting h e ld o n Wedn esday , 8 March , 1876

Adjo urn ed D iscussio n o n Dr. W ern er Siemen s’s Paper

No te s o n Dr. W e rn er Siemen s’s Pape r , by J. J. P . Bruce Warren

Pro ceedings of Me e ting h e ld o n Wedn e sday, 22 March , 1876

Commun icatio n from Dr. W ern er Siemens in R eply to the Discussio n o n

Paper On Electric Repeaters fo r Railw ay S ignals,” by W . Lang do nDiscussio n o n th e abo ve Paper

Proceedings o f M e eting held o n W edn esday, 12 April, 1876

Adjourn ed Discussio n o n Mr. Langdo n’s Pape r

Paper On the W ork-Value o f Ele ctro-Magn ets inclo sed in Iro n ,

” by

Charle s V . Walke r, F.R .S . F.R .A.S. Preside n t

Discussio n o n the abo ve Paper

Proceedings o f Meeting he ld o n Wedn esday, 26 April , 1876Adjo urn ed Discussio n on Mr. Walker’s PaperDescriptio n o f th e Electric Pen

New Members

ORIGINAL COMMUNI CATIONS“The Effe ct o f L ight o n the Ele ctrical Co n ductivity o f Se le n ium,

”by

W illo ughby SmithThomso n

’s Siph o n R eco rder,

” by J . A . Ew ing

Thomso n an d Jenkw 8 Automatic Curb Sender,” by J.A. Ew ing

The use o f aSo ft Iro n Co re ln SirW illiam Thomso n ’s M irro r Galvan o

meters,” by Walter Judd

PAGE

iv CONTENTS .

ORIG INAL COMMUN ICATION S— con tin ued .

The Po ro sity of Defective In sulato rs,” by J . Perry an d W . E .

A Ne w Me tho d o f taking th e Lo o p-Te st,” by Andre w Jam ie so nTo find the diame ter 3. o f aw ire to fillabo bbin o f given dime n sio n s

(o uter diame ter A , in n e r diame te r a, le ngth 6) an d pro duce agive n

resistan ce R , allo wan ce be ing made fo r the radial thickn ess e o f the

in sulating co vering,”by R . S . B ro ugh

A Ne w Fo rm o f Jo in t fo r Co ve re d W ires,” by W illoughby Sm ithNo te s o n aThundersto rm w hich passed o ve r Cle vedo n ,

” by Eustace

B utto n

The Pe rsian G o vernmen t Te legraphs,” by A . Ho utum Schindler

AB STRACTS AND EXTRACTSOn Subme rging Te legraphic Cables,” by Jame s Atkin so n Lo ngridge andCharle s He n ry B ro o ks

Lette r from J . A . Lo nn dge to Captain Galto n o n Paying-o ut Apparatus

fo r Submarin e Te legraph CablesProceedings (portio n o f) o f M e etin g he ld o n W edn esday, 26 April , 1876

Paper On Clamo nd’s Thermo-Ele ctric Battery,” by Latimer Clark, C E . 321

Pro ce edings o f Me e ting h eld o n Thursday , 1 1 May , 1876

Co n tin uatio n o f Mr. Latime r C lark’s Paper On Clamo nd’

s Th e rmo

Ele ctric Batte ryD iscussio n o n the abo ve Paper

Proce edings o f Me e ting he ld o n W edn e sday. 22 No vember, 1876

Furth er co n tributio n s from Mr. L . Clark o n h is Pape r On Clamo n d’s

Th ermo -Ele ctric Batte ryAdj o urn ed D iscussio n o n this Paper

Pape r On an e w fo rm o f Lightn ing Pro tecto r fo r Te legraph Lin e s andApparatus,

” by Andrew Jamle so nFo rm o f Pro te cto r in use o n South De vo n an d Co rn wall Railw ays

Pro ceedings o f M e e ting h e ld o n W edn e sday, 13 D e cembe r, 1876

An nual R epo rt fo r 1876Commun icatio n “On afo rm o f Ligh tn ing Con ducto r use d o n th e S tate

lin es o f Fran ce — B ertsch s L ightmng Guards— by Jn o Aylme r, Lo calHo n o rary Se cre tary fo r Fran ce

D iscussio n o n Mr. Jamie so n ’

s Paper

Co un cil fo r 1877Ne w M embe rs

Asso ciate s advan ced to Membe rship

ORIG INAL COMMUN ICATION SNo tes o n Electro lytic Po larisatio n ,

” by W . E . Ayrto n and Jo hnLightn ing Co n ducto rs,

” by W . E . Ayrto n an d Jo hn Pe rryExperime n t to Sh o w the directio n In w hich the Electric Spark ten ds to

trave l ,” by Caplain R . G . Sco tt, R .E .

Obse rvatio n s o n aThun dersto rm w hich passed o ver Para o n the 27th

D ecembe r, 1876, by G . B . SlaterOn th e Co rrectio n s to be applied to the apparen t re sistan ce o f the Co nducto r an d In sulato r o f aTe legraph Lin e w hen de te rmin ed In the usualw ay by Wh eatsto n e

’s B ridge ,

” by C . Ho ckin , M .A .

CONTENTS .

O RI GINAL COMMUNI CATIONS— con tin ued .M e n

On the magn itude o f the Signals rece ived through aSubmarin e Cablew ith various co nn e ctio nsat each e nd, and the be st resistan ce for the

R eco rding Instrumen t,” by C . Ho ckin , M .A .

V e rbatim copy o f Pro fe sso r (Erste d’s Original Commun icatio n , in w h ich

h e an n o un ced his disco very o f Electro-Magn etism Experimen ta

circaefi ectum co nflictus Electrici in Acum Magn eticam

English Tran slatio nHan s Christian (Erste d — M emo 1r, by L . C . Madse n

On Duplex Te legraphy,” by J . J. Fah ie

On th e Co n structio n o f Cable Keys,” by James GravesQuadran t Electrometer w ith B ifilar Suspen sio n ,” by W . E . Ayrto n andJo hn PerryOn an e w mo de o f studying Earth Curren ts and the variatio ns in Ter

restrialMagn e tism

De scriptio n o f Sir Charle s W heatsto n e ’s Automatic In strumen t,

" byCaptain V . Ho skioer, R oyal Dan ish Engin e e rs

Le tter from Mr. J. J . Fah ie On the In te rnal Re sistance o f Batterie sLe tter from Mr Andrew Jamieso n On aNew Me th od o f taking theL o o p Test

On B e ll’s Te lepho n e ,” by Juo . Go tt

ABSTRACTS AND EXTRACTSTran smissio n o f

.

Musical To n es by ElectricityBe ll’s Articulating Te leph o n eTh e Te lepho n e .

” Pape r by W . H Preece , M .I.C.E. read befo re theB ritish Asso ciatio n

The Electricity of Leave s

Tall Ch imn eysan d Electric Co nducto rs

ERRATA.

V ol. V . No s. 15 an d 16 .

Page 346 , lin e 7, for dimin ished read direct .

Page 353, lin e 22, for radial read radian t .

”

Page 384 , lin e 8 , for K read lightn ing.

”

Page 385 , lin e 8 , fo r can ”read cann o t .

”

Page 385 , lin e 25 , fo r pre ssure read presen ce .

Page 387 , lin e 22, for fo rced read fused.

”

VOL . V. 1876 . No . 13.

The Fo rty-first Ordinary Gen eral Me e ting w as he ld o n Wedn e sday,

the 12th January,1876

,Mr. C. V. WALKER

,

Pre side n t,in the Chair.

At the commencemen t o f the pro ce edings the Chair w as take nby Mr. LATIMER CLARK , w ho ro se and saidGENTLEMEN

,I have n o w the pleasure to re sign my late

fun ctio n s for the past year, and to vacate this Chair in favo ur o f

Mr. C . V. Walke r, o ur n ew Pre side n t.The Chair having be en taken by the Preside n tMr. W. H . PREECE said : It is my pleasure to -n ight to have to

propo se to the So cie ty avo te o f thanks to o ur re tiring Pre siden t,Mr. Latimer Clark, for the un ifo rm atten tio n he has paid to hisdutie s during the past year. I have e spe cialpleasure in do ing this,be cause it is n o w tw en ty-five years ago sin ce I first e n te red thefie ld o f te legraphy as Mr. Latimer Clark’

s assistan t in his o ffice,

and many atime and o ft I have spent days and n ights trave llingover lin e s in such w eather as this, sitting o n ro cks and musingo

’er flo o d and fe ll w ith Mr. Clark, w atching fo r the vagarie s o f

e le ctricity w hich then w ere develo ping themse lve s to us fo r the first

time ; and n eve r shallI fo rge t the pleasure of tho se days in searching in an e w fie ld fo r n ove l e ffects and n e w ideas in company w itho n e w ho se mind w as so w e ll qualified to in struct an d direct mymo re youthful mind. The So cie ty itse lf has n o doubt gain ed.

V OL. V . B

2 INAUGURAL ADDRESS . [12th Jan .

mous credit throughout the w hole w o rld thro ugh having at itshead aman o f such emin en ce as Mr . Latimer Clark, and his w idespread reputatio n has do n e much to in crease the popularity o f o ur

pro ce edings an d e spe cially of o ur journal . His co n n ectio n w ithte legraphy can n ever be fo rgo tten , fo r the re is scarce ly abran ch o f

it, w he the r o n lan d o r submarin e lin e s, w hich is n o t in some w ayasso ciate d w ith the name o f Clark, e ither by the improveme n tse ffe cted by his bro the r , o r by the greater improveme n ts he has himse lf introduced . No r can w e forge t the atten tio n and co n stan t

attendan ce w hich he has given to our me e tings, and the care w ithw hich he has pre side d o ver o ur discussio n s. No o n e can fo rge t hiso w n adm irable addre ss upo n the lo ss o f our greate st membe r durin gthe past year

, Sir Charle sWheatsto n e . It is o n e o f the few pape rsw hich w ill live fo r years in our e n dearing re co lle ctio n . Again

,w e

cann o t fo rge t the ho spitality w hich w e have re ce ived at his han ds,

fo r certain ly the so irée at W illis’s B o oms w as o n e o f the mo st suc

ce ssful,mo st pleasurable

,and mo st de lightfulw e have had. I am

the refo re qu ite sure yo u w ill allcordially agree w ith me in co nveyIng o ur thanks to Mr. Latimer Clark fo r his great atten tio n to thedutie s o f his office during the last tw e lvemon ths.MAJOR WEBBER

,R .E. : Mr. Pre e ce has left me very little to

say . He has touched upo n alltho se po in ts w ith w hich you are so

w e llacquain ted in regard to Mr . Clark’s co n n ectio n

,n o t o n ly w ith

this So cie ty but w ith the histo ry o f te legraphy,therefo re I can

o n ly follo w him up by seco n ding his propo sitio n , that avo te o f

thanks be earn e stly acco rded to our past-Pre side n t, n o t o n ly fo rhis assistan ce in the fo rmatio n o f this So cie ty in its early days

,

an d his co n stan t atte ndan ce at the me e tings, but also fo r the

ho spitality w hich he sho w ed o n alate o ccasio n in e n te rtain in gthe members o f the So cie ty and the ir frien ds and so large anumbe r o f perso n s co n n e cted w ith the scien tific w o rld . I beg to

se co n d Mr. Pre ece’s mo tio n , an d to ask you to acco rd to Mr .

Latimer Clark that w hich he has so w e ll earn ed.

THE PRESIDENT : It has be e n propo sed by Mr. Pre ece, and

se co n ded by Majo r Webber,that the be st thanks o f the So cie ty

be given to Mr. Latimer Clark fo r his able co n duct in the chairduring the Sessio n w hich is n o w ended. No thing I co uld say

INAUGURAL ADDRESS. 3

w o u ld add to w hat you have heard, and I am qu ite sure you w illgive yo ur be st thanks w ith acclamatio n to Mr. Latime r Clark.

The mo tio n having be en passed by acclamatio n ,Mr. LATIMER CLARK said : I am much to uche d by the man n er

In w hich this mo tio n has be en pro po sed by Mr. Pre e ce and rece ivedby the me e ting. It comes w ith e spe cial grace from him fo r the

reaso n s he has stated . Througho ut almo st the w ho le o f my

lo ng co n n e ctio n w ith te legraphy I have had the pleasure ofkn o w

in g Mr. Pre ece in timate ly, an d I can say n o mo re than thatI fe e l de eply the w ay in w hich he has put and you have re ce ivedth e mo tion . I can o n ly add that my co n n e ctio n w ith this Societyhas be en to me the highe st so urce o f pleasure and gratification ; myatte n dan ce here has be en alw aysalabour o f love , and I hope I maylo ng be spared to ren der w hat assistan ce I can in the promo tio n of

the in te re sts o f the So cie ty.

The Presiden t then pro ceeded to read his inaugural address.

In accordan ce w ith custom,w hich in practice has become law ,

it is my duty to addre ss you befo re o ccupying this Chair ; but Ihave ye t an o ther duty to perfo rm— o n e w hich has aprio r claimupo n me— to thank you for having place d me in this high po sitio n .

It is o n re co rd, and there is much truth in it, that some men arebo rn to ho n ours ; some men achieve ho n ours

,and some men have

ho n ours thrust upo n them . The last is my case . You have raisedm e to apo sitio n to w hich I , of allmen

, w ould have bee n the lastto aspire , having do n e so little , having be en unable to do anythingbut so very little , fo r the So cie ty o f Te legraph Engin e ers sin ce

you hon oured me w ith aseat at the Coun cil Board . You havew ithdraw n me from comparative re tiremen t to o ccupy this Chairto pre side o ve r the me etings o f a. body of men amo ng w hom aremany w ith far higher claims to pre side over me than I over them.

And you have raised as it w ere an outsider to this high po sition,

o n e,that is, w ho se lo t w as cast o utside the limits o f the great Te le

graph Compan ie s, having fo r many years con tro lled and w atchedo ve r the in te re sts o f alittle — by compariso n— alittle se lf-co n tain edte legraph kingdom— name ly, that o n the South Easte rn Railway .

B 2

INAUGURAL ADDRESS . [ 12th Jan .

A ske tch o f the te legraph system o n this railw ay may be auseful co n tributio n to the histo ry o f te legraphs in this co un try .

There are some specialfeature s about it w hich mav be kn o w n to

many membe rs of this So cie ty, but w hich are n o t gen e rally kn o w n .

This system an te -date s the formatio n , if n o t the co n ceptio n eve n ,o f the Electric Te legraph Company.

”The o riginal agre eme n t

be tw e e n this Railw ay Companyand Mr. (n o w Sir William Fo the rgill) Co oke , is dated the 1 1th o f Septembe r, 1845 ; but co n stru e

tio n w as begun some mo n ths in an ticipatio n o f this date . The

terms o f the agre emen t w ere , that fo r the main lin e , be tw e e n

Lo ndo n and Dover, afour-w ire te legraph sho uld be co n structe dfo r £225 pe r railw ay m ile , in clusive o f in strume n ts and batte rie s ;and that fo r bran ch lin e s athre e -w ire te legraph should be e re cte d,at aco st o f £175 pe r railw ay mile

,exclusive o f in strume n ts an d

batterie s : the co n tracto r at the same time underto ok to ke ep thelin e s o f te legraph , o riginally e re cted under this agre eme n t, in go o dand efficien t repair fo r o n e year afte r the comple tio n o f the first

half o f the main lin e . The Te legraph Engin e e rs o f 1876 w ill bein clin ed to ho ld the ir breath at hearing o f the price paid in 1845 ,o r thirty-o n e years ago , and to regard the te legraph in tho se daysas arathe r co stly luxury ; and so it w as. But if o n e o f the the nRailw ays, w hen the iro n road w as bare ly in its te e n s

,an d traffic

w as comparative ly so small, could bo ldly ve n ture to make apur

chase such as I have described, w hat excuse can any Railw ays o fto -day have , if they fail to avail themse lve s o f allthe advan tage sto be derived from e lectricity ? the mo re so

,as the ben efits are in

these days to be acqu ired at aco st— by compariso n— so mo de rateBut large though the o utlay w as

,and large r stillas it has be com e

w ith the exten sio n o f the Railw ayan d the creatio n o fn ew n e ce ssitie s,

n o be tte r inve stme n t cou ld have be e n made . Un de r the te rms o f

the agre eme n t, the Te legraphs e re cted became the abso lute prope rtyo f the Railw ay Company, as much so as are the lo como tive s

,the

carriage s, o r the rails. And so they remain to this day. Theyw ere e rected e sse n tially fo r railw ay purpo se s

,and w ith n o ulterio r

o bje ct in vie w ; an d, having be e n purchased at aprice that co u ldbe fe lt, it is n o matte r o f surprise that the Company w ere far m o re

dispo sed to ho ld them again st allcomers than to part w ith them .

INAUGURAL ADDRESS. 5

Hen ce , n o tw ithstanding the seve ral o vertures that w e re from timeto time made , they still remain

,as I have said

, the abso luteproperty o f the Railw ay Company. But the public w ere n o t o n thisaccoun t excluded from them ; for in the first in stan ce they w ereopen e d fre e un der spe cialcircumstan ce s

,and w ithin ce rtain limits.

Shilling me ssages had be en establishe d at an earlier date o n the

Great We stern Railw ay, be tw e e n Paddingto n and Slough . Ho w

so o n after 1846,Jun e 18

,the date o f the Act

, the Ele ctricTe legraph Company open ed to the public

,I cann o t remembe r

,but

o n August 15, 1846, the follow ing circular, bearing my signature ,w as issued by autho rity o n the So uth Eastern Railw ay

I find that many private message s are rece ived fo r gen tleme nto sen d to differen t parts, e ithe r fo r letters, small parce ls, o r thingsof that sort. I beg to say that the Directo rs do n o t allo w this use tobe made of the te legraph, and that it is to be used en tire ly for theCompany’

s service , except in extreme cases, w here kindn e ss o r

human ity w o uld dictate , such as illn e ss, death, &c.

,and fo r the

public press at Fo lkesto n e , and the n o n ly to alimite d exte n t.”

The se privilege s, ho w ever, laste d fo r afe w days o n ly ; fo r o n

the first day of the fo llo w ing mo n th rate s w ere issued. The scalew as based upon thre e -halfpen ce per mile fo r tw e n ty w o rds

,the

m in imum be ing five shillings. The rate from Lon do n to Doverw as to Ramsgate 12s. 6d.

I w ellremembe r aremark that w as made at this time,and it

came from n o mean authority, that it w ould n o t do to make thete legraph rate s to o lo w fo r fear o f reducing the traffic rece ipts o nthe railw ay

,by inducing passengers to use the w ire in stead o f the

train ; and he n ce aParliame n tary fare and ahalf, o r thre e half

pen ce , per m ile , w as adopte d . From that date un til February 5,

1870,w he n the go odw ill w as tran sfe rred to the Po st Office , the se

railw ay te legraphs w ere open to the public as fe eders and distributo rs fo r the Te legraph Compan ie s proper. And n o w

, as agen tsfo r the Po st Office , the Railw ay Company ke ep office s ope n

,and

deal w ith me ssage s o n commissio n .

Man y po stal te legraph office s having be en e stablished in partso f B erkshire , Ken t, Surrey , and Sussex, served by this lin e , andto the re lief o f the railway w ire s, and as the Po st Office w ere in

INAUGURAL ADDRESS. [12th Jan .

urge n t w an t o f w ire s,the Company w ere able to spare and (as the

property w as the ir o w n , it w as in the ir pow e r) to se ll them som e

thre e o r fo ur hundred mile s.Meanw hile

,the service o f the Railw ay and the comfort and

safe ty of the trave lling public w ere the prime obje cts of co n side ratio n ,and w ere alw ays kept promin e n tly in view .

“Onw ard”is the

mo tto o f this Company ; and true to the ir mo tto have they prove dthemse lve s. This w as the more easy from the ir be ing un fe tte re dfrom w ithout. They w ere able to turn the ir fre edom to go o daccoun t. What time an ew w an t aro se , they co uld me et it fromthe ir o w n resources. In n o matte r have they taken amo re prom in en t po sitio n , and o n e mo re in advan ce ofmany o r mo strailw ays,than in train-signalling .

” They began this very early, lo n gbefo re in strumen ts spe cially adapted to the w ork w ere co n structe d.The speaking in strumen ts , double o r single n e edle , w ere used

,an d

almo st w itho ut exceptio n w ere the same that w ere also employe dfor service and fo r public me ssage s. Eve n in tho se days, w he ntrain s w ere so fe w ,

this w as acase o f w o rking under difficultie s.

The o riginal circular o f in structio n s,dealing w ith the te legraphs

gen e rally,and train -signalling e spe cially

,that bears my signature

,

w as issued in 1846 February 16. It o rde red that “The arrivaland departure o f every train is to be te legraphed to the n ext up

and the n ext do w n statio n s ; o r in o ther w ords,that the speaking

in strume n ts (w hich fo r me ssage purpo se s are in groups) w ere to beused fo r o rdinary train -signalling

,w hich w ork

,as I n e ed hardly

say , w as do n e but in diffe re n tly, even w hen train s w ere as at thattime few and far be tw e e n . But in course o f time

,as traffic

increased, the cry w as for mo re e le ctricity,and ye t more and the

impo rtan t step w as tak en in Jan uary 1852 o f e re cting aseparatew ire an d co n structing an e w class o f in strume n ts spe cially adapte dfor train -signalling alo n e

,and available fo r n o thing e lse .

There w ere so many train s to talk abo ut,an d so much to say

abo ut each, and to say it o n the in stan t,that the re w as n e ithe r

time to spe ll w o rds n o r to read them if se n t, eve n had there be e nhands at liberty to send

,and eye s to se e and read

,w hich the re

w ere n o t.

The ear alo n e w as at liberty, and the n ew instrumen ts n e w

1876 ] INAUGURAL ADDRESS

pro vide d spoke to th e ear, and said allthat had to be said byafe wsimple sounds o n single -stroke bells . This w as fo llow ed by theissue , on March the lst

,1852, o f bo oks in w hich w e re registe red

the signals made and the time o f makin g them , n o t o n ly as ape rman e n t re cord fo r future referen ce , but as an aide-mémo ire to the

statio n w e re made to e n ter every gate -house at le ve l-cro ssings,fo r

the info rmatio n of the gateke epe r ; and w ere also led o nw ard tothe platforms, so that the station stafi

'

might kn o w w he re the train sw ere .

On January 30, 1860, just fifte en yearsago , and befo re the nu

happy expressio n “block system w as w e ll kn o w n, the spe cial

w ire was comple tedand the new in strume n ts co nn ecte d up througho ut the w ho le o f this Railway, and e very in ch o f the lin e hasbe en w o rked from this date on the “blo ck system ” pro pe r.

While this w as in progrem, roads as w ellas train s w e re iu

creasin g in n umber , and each road re quired its w ire and pair o f

instrumen ts. Refe re n ce to the registe r bo ok as an aide-M o ire

be coming more or less impracticable , an additio n w as made to thesoun d-in strumen ts, o f such acharacte r that

,w hile they still ad

dre ssed the ear,and the me ssage w as o n its w ay to the ear, it left

its mark visible o n the face o f the in strume nt, w hich mark w as

retain ed there until the cause for its exhibitio n had passed aw ay,sho w in g at aglan ce at any momen t the the n co ndition o f everyroad. Mo re re ce n tly the variety o f trains o n the same road has soin creased that the bells have be e n suppleme n te d by an o ther instrume n t that po in ts to the name itse lf o f the train that is coming ;and so o n . On the first o f the prese n t mo n th, 865 instrumen ts,includin g repeate rs, w ere in use fo r the “blo ck system ’

o n 328

I should add that the Railw ay Company established ate legraphstaff o f the ir ow n from the ve ry first, and themse lve s carried o ut

comstructio n and main tenan ce ; alw ays moving “o n w ard.

”If n o t

pio ne ers at allpoin ts, they Se em to have be e n in many ; at leastthey w ere no laggards. At any ‘

rate they began early to pro ve

INAUGURAL ADDRESS . [12th Jan .

that aRailw ay Company, in its o w n in te rnal strength , could w ithcredit main tain its po sitio n as its o w n Dire cto r and Manager o f

Te legraphs.

They have also do n e much w ork beyon d the ir o w n w an ts, and

also outside the ir o w n gate s, having ere cted and main tain e d te legraph lin e s o n the ir o w n prope rty for the Ele ctric and fo r theMag netic Te legraph Compan ie s and for the Po st Office , as w e ll aslin e s for the Po st Office o n the public roads, and po stal te legraphofi ce s in to w n s and villages. Some te n years ago they in troducede lectricity in to the ir train s, and have already fitted up aboutvehicle s, andare stillgo ing “

on w ard in this w o rk.

Mo re than tw en ty-thre e years ago , in co -operatio n w ith the Astron ome r R oyal, they w e re the first to inaugurate the distributio n o f

time by te legraph.

Mo re than e ighte en years have passed sin ce they w en t outsidethe ir o w n gate s w ith clo cks an d w atche s for repairs. They have inallabo ut 800. The ir o w n pe ople

,the te legraph staff

, clean andrepair them ; beside s having made some fifty o f the clo cks. Are

theyalon e,o ralmo stalo n e

,in this ? The autho r of Se lf-he lp

,

” Mr.

Samue l Smile s, w as for some years Se cretary to the Company . I

think he w ould agre e w ith me that the prin ciple o f se lf-he lp, which

he so stro ngly advo cate s, has n o t be e n badly carried out,at least inte legraphy, 0 11 the railw ay to w hich he w as attached .

The substan ce o fmuch that I have be en saying is that railw ayso w e ade ep debt o f gratitude to e lectric te legraphs. But the debtis n o t allo n o n e side . The fo llo w ing remarks o n bo th side s o f theque stio n w ere w ritten in March 1850

The e lectric te legraph is greatly indebte d to railw ays if n o t

fo r its existen ce at least for the friendly hand they have he ld o ut

to it, and fo r the pro te cting care w ith w hich they have guarde d it ;inde ed the inven tio n w ould lo ng have remain ed immature d andvo id o f practical existe n ce had n o t the railw ay prepared fo r it apathw ay from place to place

,alo ng w hich its capabilitie s cou ld

be te sted . No r has the child be e n ungrate ful to its fo ster-fathe r ;it has made ate n fo ld return fo r allthe pro te ctio n that has be e nexte nded to it. The quie t po le s and sile n t w ire s

, the zin c and the

m W ON DER o f the A GE I !INSTANTANEOUS COMMUN ICATION.

Under the tpeciall‘atronage ofHerMajesty Bart ram Albert.

m GALVAN O AND u se rs o -m auame

ON 7 8 8

GT.WESTERN RAILWAY.

fl q h m in W om an”(Sundays “eq uati on : 9 till8 , at th eTELEGRAPH“F108, LONDON TERMINUS, PADDINGTON

AND TELEGRAPHCOTTAGE, S LOUGHSTATlON.

An W o n adn itfi by itlnm m m Vifiw r-to be the mou inmu tin'M Am am n o f sny in thin

'

le tmpolin. In thc list of visito n m tbcillu triom m d m m lo f m ned Hu do d Em m md nw ly thcw holo oltc obility olEDglw d.

“M M M M M M m m m q , tr ad

m m mm u a~m mm q n m "— u o m o Pm .

The Telegraph h n lin dud in thc n mn n d m n t ol ia e oamunicnficn g by iu m dim -

y nge o cya in lm don eo nld con veroe w ith

ano ther-S Nw YaL or st w y otbc plm dim -s nailym d nw ly u

mdly u if bo th pc fiam in tho m m m. Que-tim propon d by V iaito nbe d d bymu m olthisAppc fi m mdm m tha-ao v illinm

b ummed byapc m to mlu o fll w bo w illM d tha’r n qm fi ngaw h am m m w fi y w w d m w m w mr hhdoh g oo hu be en given .

Th e Ele ctric Flu id trav els at th e

li n em an ln .

NM M AB , “M UL W M

https://www.forgottenbooks.com/join

10 INAUGURAL ADDRESS. [12th Jan .

lin e o f te legraph so lidly ere cte d than ago od straight cou ntry roadto le rably fre e from tre e s . The w ire s in the ope n are n o t expo se dto pe rn icio us vapo urs and w ill have ave ry lo ng life

, and in passin gvillage s they are n o t exposed to such de structive age n cie s as w he nn ear passing train s o r railw ay w o rks ; n o r do I think they aremore liable to in terruptio n s.

” And so o n .

The ope n co un try w as co n side red equally un safe w ith publicroads

,&c.

,and n o o n e ven tured

,as n o w

, to carry railw ay w ire so ve r

,in place o f thro ugh

,tun n e ls. Ope n w ire s w e re hung in the

tun n els, w ith w hat effe ct o n the signals you may w e ll imagin e . In

the year of Revo lutio n s, 1848, the te legraph signals, that co nveyedthe exciting co n tin en tal n e w s from the coast to Lo ndon BridgeStatio n , w ere so w eak that n o n e but avery practised eye co uldse e the slighte st sign o f mo tio n in the lo ng n e edle s then in use

,

w hich led the the n Chairman to ask the clerk w he ther he w as

actually reading off the w o rds he w as dictating to the w rite r.

At this time , w hen so much w an ted,gutta-pe rchabegan to be

kn ow n . The first w ire s to w hich it w as applied he re w ere No . 8

galvan ised ope n w ire s, o n the Dover viaduct,in November 1848 .

Begin n ing w ith Decembe r 1848, and en ding w ith July 31, 1849,w ires in sulated w ith gutta-perchaw e re suspended in alltunn e lsbe tw e e n Lo ndon and Dover. Mean w hile the Compan y had madean o ther movemen t in the “

o n w ard directio n . Tw o mile s o f theabove w ire w ere jo in ed up, w oun d o n adrum

, and take n to Fo lkesto n e

,and co n n ected up w ith an open w ire

,that w asled in to asingle

n e edle in strumen tat Lo n do n Bridge Statio n . The drum w asput in toasmall boat and row ed o ut to sea, the w ire be ing at the same time

paid out. The end was taken to o n e of the Company’s steamships

,

o n board of w hichalarge party o f visito rs w as assembled,and the re

co n n ecte d up w ith asingle -n e edle o n the Lo ndo n w ire . At 12 4 9

p m ,Jan uary 10, 1849, the fo llo w ing me ssage w as se n t dire ct to

Lo n don thro ugh the tw o m ile s o f submarin e and 83 mile s o f lan dlin e — Mr. Walker to Chairman , I am o n board the P rin cess

Clemen tin e . I am succe ssful .”1' Was this the first submarin emessage , or the first se n t direct to Lon do n ?

Charles V . Walker, Dec. 29, 1868, in reply to Mr. Scudamo re , Sept. 23, 1868.

t Walker’sElectric Te legraph Man ipulation , p. 104, 103.

INAUGURAL ADDRESS . 11

Be fore leavin g the So uth-Eastern Railw ay I must say o n e w o rdo n the quality o f the mate rial and the high characte r o f the w ork

handed o ver byMr. Co oke . It w as simply beyo nd praise . The w irew as best charcoal, galvanised in the be st w ay. It is n o matter o f

surprise that most o f this in the ope n coun try remain s in vitato thisday , and w e have n o bette r w ire to handle . It is amatter, to o , o f

agre eable surprise that many o f the po le s o f 1845 are still standing.

I have lying before my o ffice w indo w apo le marked o riginal ;”it

is really as so un d, so to speak, as ever. It is on e o f afe w take ndo w n fo r alte ratio ns some mo n ths sin ce . The po le s w e re o f

seasoned fore ign timbe r, tapered , chamfered , Burn e ttized, andpain ted . Some of the o riginal D . N . pillar instrume n ts are stillin use , w hile many o f later date s from o the r so urces are w orn

o ut.

As Mr. Hatche r was o n the eve o f comple ting his w o rk , Mr.

Co o ke in troduced me to the o ffice I still ho ld , name ly, in October1845

,just thirty and aquarte r years ago . Lo oking back to this

distan t date , I cann o t he lp thinking that I must be the o lde stTele graph Engin ee r in England ,— at least the o n e lo nge st in te nureo f the se lf-same o ffice ,

— the o n e w h o has had so le charge as Re siden t Engin eer o f the same w o rking system o f Electric Te legraphs fo r the lon ge st te rm o f years. I may w e ll behave that tomy having take n o ffice thus early, and having he ld this self-same

ofi ce so lo ng and so te naciously, is due , mo re than to any pe rso nalfitn ess o n my part, the ho n o ur yo u have co nfe rre d upo n me .

With the names o f Sieme n s, Scudamo re , Thomso n , and Latimer(flark

' haun tin g me , I take this Chair w ith fe e lings o f anxie ty .

The de ep scien ce o n the o n e hand, and the admin istrative capacityon the o ther, w hich the so und o f the se name s e voke s

,co n vinces me

that I shall have to claim,and I am sure shall re ce ive , yo ur for

bearance and indulge n ce for any lad ies o n my part.This So ciety by its ve ry title is pure ly te chn ical

,pro fessio nal ,

utilitarian ; and I agree w ith yo ur late Preside nt in regretting “that

w e have no t ye t e nro lled in o ur ranks, to any great exte n t, thatlarge bo dy o f private scie n tific w o rke rs w ho love and pursue thescien ce o f e lectricity w itho utany tho ught o f regarding it as aprotemion .

" He gave yo u the name o f aSocie ty that did this, and

12 INAUGURAL ADDRESS . [ 12th Jan .

in do ing so to ok you back to date s earlier than tho se that I have be e nbrin ging be fo re yo u. I shall have to take you to stillearlier date s, todays w hen the utilitarian could raise the que stio n— and it w as more

than o n ce put to myse lf— What is the use of e lectricity ? Whatdo you expe ct to gain by it ? Do e s it pay ? There w ere n o e le ctric te legraphs the n n o e lectro type fo r in stan ce ; n o plating an dgilding by e lectricity.

The Lo n do n Ele ctrical So cie ty w as founded o n May 16 ,1837 . It had a short life o f six years, w hen it succumbe d, asw e shall se e , to chro n ic atrophy . Its “lin e s may n o t have bee nhappily “laid

,

”o r it w as premature , o r the hands by w hich it w as

guided w ere n o t many e n ough o r strong e n ough. If it may havebe e n fo rmed to o so o n

,it ce rtain ly co llapsed to o so on — just at the

time in fact w he n the po w er o f e le ctricity w as making itse lf fe lt,in

the practical realizatio n o f Co oke and Wheatsto n e ’s te legraphs.

Had it he ld its gro un d o n ly alittle lo nger,it might have survived

to this day, and have become aChartere d So cie ty (as I trust o ursw ill be come ) o f w hich allo f us might n o w be Fe llo w s ; e le ctricityproper and e lectricity applied be ing cultivate d by o n e and the samebody co rporate .

In the first An nual Addre ss, de livered at aGen e ralMe e tinghe ld in the Theatre o f the Gallery o f Practical Scien ce , Ade laideStre et, Stran d , o n Saturday, October 7 , 1837 , I read : “ In the

spring o f the pre sen t year I de livered acourse o f le cture s o n

Ele ctro -Magn e tism and Magn e tic Ele ctricity ,’ at Mr. Clarke ’

s,

philo sophical in strume nt maker, Low the r Arcade . At the clo se o f

each even ing’s lecture aco nve rsatio n ge n erally en sued amon g the

ge n tlemen w ho ho n o ured me w ith the ir atte ndan ce ; and the w an t

o faSo cie ty fo r the e n courageme n t o f e lectrical pursuits w as o ccasio nally spoke n o f an d un iversally ackn o w ledged. On the 16th o f

May afe w o f tho se gen tleme n me t,and

,after some discussio n as

to the be st mode o f establishing such aSo cie ty, it w as agre ed thatthe attempt should be made . The first o f o ur me e tings to ok placeo n the l0th o f Jun e

,and they ‘

w e re co n tinued each succe e din gSaturday un til the 12th o f August

,the n umbe r o f m embers gra

dually in creasing the w ho le o f the time . On each eve n ing o n e o r

more papers w ere read,and seve ral an imate d discussio n s to ok

1876 ] INAUGURAL ADDRESS . 13

place,visito rs be ing allo w ed by the Rule s o f the Socie ty to take a

part. ”

The se remarks w ere made by Mr. William Sturge o n , w ho hadtake n the chair at the May me eting refe rred to . He had be e n an o n -comm ission ed o ffice r in the Royal Artillery, and at the timeo f w hich w e are speaking w as Le cturer o n Experimen tal Philosophyat the Ho n ourable East In diaCompany’

s Military Seminary,

Addiscombe , & c.,&c. He do e s n o t te ll us w hat he himse lf had

be en do ing in the in te re sts o f Ele ctricity, apart from his dutie so f o ffice . He had e stablished the An nals of Electricity, &c.

,the

first number o f w hich w as published in October 1836. It w as a

half-crow n o ctavo magazin e . In the first in stan ce it appeare dquarte rly

,the n the May number is fo llo w ed by o n e in July, then

a leap to Octo be r,and then mo n thly

,and then o therw ise . The

publicatio n cease d w ith No . 60,vol. x.

,in Jun e 1843. It w as

follo w ed by the An nals of P hilosophicalD iscovery and Mon thly

R ep orter of the P rogress of P racticalScien ce , o f w hich o n ly fiven umbe rs appeared, the first in July, the last in No vembe r, 1843.

In the R oyalS ocie ty’

s Catalogue of Scien tific Pap ers (1800

1863) Mr . Sturge o n appears as the autho r o f sixty -n in e papershis first in Tilloch

’

s Philosop hicalMagazin e , in 1824 , o n Ele ctroMagn e tical Expe rimen ts his last in the Manchester P hilo sop hical

So cie ty’sMemo irs

,in 1857 , o n Some Peculiaritie s o f the Thunde r

sto rm w hich o ccurred n ear Pre stw ich, 16th July,In Sturge o n ’

s An nals alo n e w ill be fo und areco rd o f the com

mun ication s made to the Lo n do n Electrical So cie ty from the first

o rdinary me eting o n Jun e 10 to the me e ting o n Octobe r 7, 1837 .

They co n tain also full repo rts o f the me e tings ; and the Papers readare prin te d in abstract o r in exten so . Yo ur Pre side n t jo in e d theSocie ty o n April 7

,1838 ; and o n Jun e 2 tried his ’pren tice hand

as amember o n rather akn o tty subje ct, On the Effe cts o f the

Iro n used in co n structing Ships (especially that in Iro n Steam

V e sse ls) upon the Marin er’

s Compass,” prin te d i n ew tenso in the

An nals, vol. iii . p. 1.

The Ge n e ral Steam Navigatio n Company had just then added tothe ir fle et the iro n steamship Rainbo w ,

”w hich

,I be lieve

,is still


run n ing ; and my atten tio n had bee n called to the very bad behaviour o f the compasses in its voyage from Live rpo o l to Lo n do n .

The fo unders o f the So ciety , tho se pre se n t that is at the first

me eting, w ere : Wm. Sturge o n , in the chair, J. P . Grassio t,J. E. John so n

,W . Le ithead, and W . B . Lyn n

,five in all The

Electrical Socie ty o f Lo ndo n w as the title first an n oun ced w hichsubsequen tly be came The Lon do n Ele ctrical So cie ty . Mr.

Gassio t w as appo in te d treasure r and Mr. Patrick secre tary .

At the n ext me e ting the re w e re a couple o f visito rs,bo th o f

w hom in due course became members,and o n e o f w hom ,

Mr .

Po llo ck, w as the autho r o f the first paper read at the first o rdi naryme e ting

,Jun e 10

,1837

,

“On the same cause un de r diffe re n tcircumstan ce s pro ducing the varied phen omena o f the diffe re n tScien ce s o f Electricity

,Galvan ism ,

and Magn e tism . Of thispape r n o reco rd remain s but the autho r w ro te subsequen t papers,in w hich he w o rked o ut his ideao fa Un ive rsal Principle . The

first pape r prin ted by the Ele ctrical So cie ty w as also by him,

e n titled, The actio n o f the Vo ltaic Batte ry sho w n to be tw o -fo ld,and the distin ctio n be tw ee n the terms Quan tity and In te n sityde term in ed by the The o ry o fVibration ; w ith areply to the variousobjection s made to the The o ry .

”

This is arather tempting and captivating subject to the membe rso f this So cie ty ; but I fear it w o uld hardly ho ld its o w n in the sedays o f Vo lts, Micro-farads, Wheatsto n e

’

s Bridge, Ohms, and

Po te n tial .Befo re parting w ith Mr. Po llo ck, w ho w as aw e ll-kn o w n chem ist

o f Fe n church Stre e t, I may men tio n as a curio us fact,and as a

singular mark o f distin ctio n, that he w as n ever absen t from a

single Committe e o r Ordinary me e ting from the time he first madehis bo w o n May 20, 1837, un til he sign ed his name as Chairmanat the finalme eting of the Committe e forw in ding-up o n October 28th ,1845 .

The last ordinary me eting o f the So cie ty w as he ld o n March 21,

1843,and the last paper read w as “On the actio n o f Tre e s in

co nde n sing Atmo sphe ric Vapo ur,

” by Charle s V . lValker,ho n .

sec. The ho n o rary se cre tarie s in o rder w ere— Tho s. Patrick ,

Je ffrey,and E.W . Brayley. The mean ten ure

as about six mo n ths. I fo llow ed Mr. Brayley,

3, le ctures, w e ll illustrated, w ere de livered be fo reo f members and visitors “On Lightning Co nPre siden t

,and On Animal Electricity byDr.

Society w ere equally fortunate w ith ourse lve s.the fre e use o f

f the Ade laide Gallery— the place n o w in the occupa

the co n fection e r— but allthe apparatus o f the Instithe ir dispo sal fo r expe rimen t and illustratio n . I maythe in fo rmatio n o f o ur younger members

,that the

w as aPolytechn ic In stitution in prin ciple,w he re

tp be se en by the gen e ral publicThe advan tage o f me eting the reo f the In stitutio n havin g be e nand

'

the theatre be ing required.

n o o rdinary mee tings be tw ee n1 and o f co urse n o pape rs read.

n e o f the Committe e underto okthat co uld be fo und o f the Pape rs

to the Socie ty since its fo undatio n , an d n o t ye t

Tran sactio ns ; and to prin t them at his discre tio n

days,subse

w as at first

19, 1842 , at

Ro yal Po lyw ere less than

to in crease as the stre ngth o f

en titled as part o f this arrangePo lyte chnic In stitutio n . The

e In stitutio n w as

theatre and the ir

16 INAUGURAL ADDRESS. [12th Jan .

in abstract or in exten so , un ifo rm w ith the papers already prin ted,and to lay befo re the Committe e in o n e vo lume are co rd o f the

w o rk do n e by the So cie ty ; w hich w as complete d and the vo lumeready o n December 12

,1840 . Allarrears w ere n o w cleare d o ff,

and the histo ry o f the So cie ty complete d as far as existing mate rialsw ould allo w . A list of the missing MSS.

— avery fe w o nly, as Ihave said— is re co rded in Sturge on ’

s An nals it is to be foun din vol. i . pp . 502-3.

It w as n o w arranged that the o rdinary me e tin gs sho uld bere sumed

,and the Member o f Committe e w ho had edited the vo lume

w as in vited, o n March 24, 1841 , to take charge o f the affairs o f

the So cie ty and to accept the o ffice o f Ho n orary Secretary andTreasure r ; to arran ge the me e tings o f the So cie ty, and to publish ,in such fo rm as he should think be st, and as promptly after eachme e ting as w as po ssible o r co nve n ien t, the Pro ce edings o f the

So cie ty and the papers read. A guaran te e fund w as e stablished,

to me et the expen se s in case o f n eed. Mee tings w ere re sumed andhe ld mo n thly, w itho ut any season o f re cess in the autumn ; and the“Pro ce edings w ere issued quarterly, each numbe r co n tain ingthe results o f thre e me e tings.The be st re feren ce I can give yo u to the w o rk do n e is in the

royal 4to . vo lume o f 210 page s, an d the royal 8vo . vo lume of 565

page s, each w ith plates and w o o dcuts.The subscriptio n w as o n e guin ea for no n -re siden t and tw o

g uin eas fo r re side n t Members. The in come from this, the chie fsource , w as very small 17s. , £72 3s., £77 14s.

,o r abo ut

£77 ayear, is allthat the bo oks show at the be st. The first listshow s 76 name s but

,as the re sult w as o n ly £80 17s.

,it is plain

en o ugh thatalldid n o t pay the ir due .

The result o fmy lo ng experie n ce , and n o doubt it is mo re o r le ssthe same w ith many o f you , is, that allSocie tie s, w he ther fo rcharity, church , club, o r scien ce , are afflicted w ith members mo reo r le ss in number w ho se idio syn cracy is to pay badly o r n o t to payat all and that ape riodical pro ce ss o f w e eding-out such unprofit

able servan ts has to be carried in to effe ct. It is to be hoped thatthe o fficers o f this So cie ty w ill n o t spare such me n

,n o r be slo w to

deal w ith them . With some it is co n stitutio nal, w ith o thers it is


o f the South Devo n Lin e in 1846, o n the staff o f the Electric Te legraph Company

,altho ugh n o t actually amember, w as afreque n t

visitor at the me e tings, and w as also ve ry much w ith Mr. Gassio t

and myse lf.Tw o se ssio n s w ere comple ted and e ight quarte rly parts o f the

Pro ce edings published ; but the pro spe cts o f the So cie ty w ere n o t

mo re promising unde r the n ew re’

gime than un de r the old. The

in crease o fmembe rs,and w ith them o f in come

, w as n o tappreciable ;an d on comparing n o te s it w as fo un d that the re sult o f the tw o

years’ labour w as adebt o f 159l. Os. 9d., and n o great asse ts. At

the an nual me e ting,o n April 8, 1843 the Secre tary in his repo rt ,

in reference to the w an t o f succe ss, said You placed me in

almo st de spo tic po w e r o ver yo ur in tere sts ; you gave me n o coun cilto guide and n o committe e to dire ct ; yo u en trusted the managemen t o f yo ur affairs to my un exercised judgme n t,and the expan sio nof the Socie ty to my lim ite d in flue n ce . Tw o years’ expe rie n ce hastaught me that I am n o t sufficien t to bear this do uble burthe nand again

,fo r he (yo ur Se cre tary) has fo r the last tw o

years be e n virtually the So ciety membe rs have ve ry farfalle n sho rt o f do ing the ir part to w ards suppo rting your Se cre taryin his en deavo urs to advan ce yo ur in te re sts and the te rm o f

my stew ardship is expired,an d I re sign my fun ctio n s as yo ur

Se cre tary an d Treasurer ; and again expre ssing my sin cere regre tthat I have be e n unable to ren der in abetter accoun t o f my

stew ardship.The usual regrets and sugge stio n s w ere made , but the Se cre tary

said that allw ould be in vain un le ss the re w ere a standin gCo un cil o fMembers w ho w o uld devo te the ir time an d e n e rgie s tocarry o n the de tails o f the So ciety.

”It w as then re so lved to call

aspe cial me e ting to take in to co n sideratio n the disso lutio n o f the

Socie ty, w hich w as he ld o n April 22, 1843 , w he n it w as de te rmin ed to disso lve the So ciety

,and the requisite measure s fo r carry

ing this in to effe ct w e re o rde red to be take n, and aPro visio nal

Committe e , to w hich Mr. Walker w as reque sted to actas Ho n o rarySe cre taryand Treasurer, w asappo in ted. The re sult may be give n inafe w w o rds, altho ugh it o ccupied tw o years and a-half to comple te .

The members ge n erally, and tho se o n the guaran te e list e spe

INAUGURAL ADDRESS . 19

cially , w e re called upo n , and in d ue course allclaims again st theSocie ty w e re me t ; and o n October 28, 1845 , the finalme e ting o f

the Committe e was he ld, tw o members, be sides Mr. Po llo ck as

Chairman and myse lfas Se cretary,be ing pre sen t.

To comple te the histo ry,the So cie ty be ing disso lved, the publica

tio n o f the Pro ce edings ceased, but the materialsandmachin eryfo r aquarterly journal remain e d

,and every thing w as in go od

w o rking o rde r. I w as then stro ngly advised to take the matte rin to my o w n han ds, and n o t allo w the publicatio n o f e lectricalpape rs to drop . I did so

,an d e stablished the Ele ctrical

Magaz in e , follo w ing in o rder N0 . VIII . o f the Pro ce e dings,”

by publishing No . I. o f the “Electrical Magazin e at my o w n

co st and risk, on July 1,1843

,and co n tinued it to Octo ber 1 ,

1846,fo urte e n quarterly n umbe rs in all. Vo lume I .

,o f e ight

n umbers,co n tain ed 628 pp. ; Vo lume II.

,o f six numbers

,480 pp .

He re my courage and stre ngth failed me . The burde n upo n timean d purse w as to o heavy to bear single -handed.

What remain n ow o f the n in e years’ labourare the four vo lume sw hich are in yo ur Library, and the influen ce mo re o r lo ss w hichthey

,and the me e tings repo rte d in them

,may have had in pro

mo ting and cultivating tastes fo r e le ctric scien ce . What remain edthen to the labourer w as the pleasurable re tro spect o f the w o rk inw hich he had be e n pe rmitte d to take so large ashare , and o f the

co nge n ial circle in to w hich he found himselfadopte d, and aheavybalan ce o faprin ter’

s bill to pay.

To co nclude . In w hat has be en said I have studiously avo ide dtaking you over groun d w e ll explo red by and familiar e n ough toyo urse lve s but un trodde n by myse lf perso nally ; and, at the risk o f

be ing te dious and o f unduly trying the patien ce o f some o f you ,

have co n fin ed myse lf to fie lds o f labour w ith w hich I have be enperso nally very fam iliar— quorum magnapars fui— but the histo ryo f w hich is more o r le ss inacce ssible to you , and is very littlekn o w n to the public o f to -day. I w o uld have made in passing afe w mo re remarks than I have do n e upo n some o f the po in ts thathave cropped up in this very brief Ske tch ; but I have passed themo ve r . having de tain e d yo u lo ng e n o ugh already.

0 2


Mr. C. F. VARLEY : Gen tlem e n , w e have heard alo ngand in te re sting addre ss from Mr. Walke r. During the first part o f his paper,w hich date s back to 1845 I may say I am able to ke ep pace w ith himfrom my o w n reco lle ctio n and my o w n expe rie n ce

,for it w as about

that time that I w as in troduced to te legraphy by Mr. Co oke ,and as

sisted him in co n tracts w ith the Ele ctric Te legraph Company in thefo llo w ing year. Mr. Walker’

s experie n ce is large and special ; andthere fo re the remarks he made , espe cially in the early part o f his

addre ss, are particularly in te re sting to allte legraph engin e e rs, be

cause it w as by the failure s o f tho se days that our pre se n t great succe ss has be en built up . Te legraphs began in 1845, an d co st the

large sum of 240l. am ile . The Pre siden t has to ld yo u also , andI can bear him o ut in this

,that Mr.

— n o w Sir William— Fo thergill Co oke spared n o pain s to ge t the be st materials available atthat time ; an d I do be lieve , myse lf, that at this pre sen t time , totake o n e in stan ce , it is w o rth w hi le— it is cheape r in the lo n g run

— to go to the expense o f using the be st charcoal w ire than thecommon stuff n o w so ld un der the name o f Extrabest be st. ” It

is an un do ubted fact, and o n e w hich w e should bear in m in d,

that aw ire compact in its structure , like that o f the be st charcoaliro n— homoge n e o us iro n— do e s n o t disin tegrate by rust so rapidlyas aw ire w hich con sists mere ly o f abun dle o f lo o se fibre s

,an d

te rmed “Extrabe st be st. Therefo re it is w e ll, and I am exce e d

ingly pleased, to hear Mr . Walker give SirWilliam Fo the rgill Co okethe praise w hich is due to him fo r having used such exce llen t w ire ;and in illustratio n o f this I may me n tio n o n e fact in re latio n to thete legraph e re cte d to co n n ect the Victualling Yard at Go spo rt dire ctw ith the Admiralty in Lo n do n . On the o ccasio n o f astorm in

1848,o n e o f the po le s o n that lin e

,35 fe e t o ut o f the gro und

, fe lldo w n

,carrying the w ire s w ith it. The four w ire s w ere stre tched n o

le ss than seve n yards in the span o f 100 ; and w he n w e came to

put up an ew po le allw e had to do w as to w in d up the extra

quan tity o f seven yards o f w ire , and the te legraph lin e w as as

soun d as before .

Mr . Walke r has refe rred to an umber o f in te re sting facts . On e

w hich w ill e specially in te re st this Socie ty w as that re lative to theremarks made by my late and e ste emed superio r

,Mr. Hatcher

, as to

187 INAUGURAL ADDRESS. 21

the impo ssibility o f laying do w n w ire s in the stre e ts o f Lo n do n . It is

asingular fact that in 1846 I to okashare in laying do w n w ire s to theprem ise s 345 Strand, w hich w as the first te legraph o ffice ope n ed inLo n do n , and tho se w ires w ere succe ssful fo r aco n siderable time .

Mr. Walker also men tio n ed the fact that some o f the o riginalte legraph in strumen ts— do uble n e edles— fo r w hich 45l. w ere charge d tomy kn o w ledge , are still w o rking to this day— an o the r te stimo ny tothe exce lle n ce o f the w o rkman ship o f Sir William Fo the rgill Co okein the early days o f te legraphy . The experimen ts that w ere madebetw e e n Fo lke sto n e and the ve sse l mo ored o ut at seamay be lo oke dupo n as probably the first succe ssful layin g o fasubmarin e lin e o f

con side rable length . There is, ho w ever, an in tere sting fact w hichshou ld n o t be lo st to o ur reco lle ctio n , and that is that in Russiaasubmarin e lin e of n early the same le ngth w as actually laid andmin es w ere fired at adistan ce o f tw o m ile s in the year 1818, andit is to that date that w e must go back, I think, fo r the first ideao fasubmarin e te legraph. I am very pleased that allusio n has be e nmade to the labo urs o f Mr. W. Sturge o n , w ho w as an in timatefrie n d o f my fathe r

’

s, and w ith w hom I have had many in te re st

ing con versatio n s and discussion s upon te legraphy. In a largequarto w o rk

,acopy o f w hich he presen te d to my father, w hich I

thin k must have be e n aco lle cti o n o f his papers, the re are n ume

rous exce lle n tly exe cute d copper-plate s o f various apparatus, w hichw ill bear in spection at the pre se n t day, and much may be gatheredfrom them . It is unn ece ssary fo r me to say anything furthe r thanthat I hope yo u w ill suppo rt the propo sitio n w hich I am about tomake , viz. that our w o rthy Pre siden t w ill be kind e n o ugh to permithis addre ss to be prin ted .

The m o tion having be e n unan imously carried, asuggestion w as

made that the o riginaln o tices re lating to the exhibitio n o f the

ele ctric te legraph at Paddingto n read by the Presiden t should be

pho to graphe d and accompany the addre ss.

THE PRESIDENT : It is ve ry gratifying to me to find that theaddre ss w hich I have read has bee n so heartily accepted. It must

in many se n ses have be e n very dry, se e ing it co n tain s so manydatesand so many matters of histo ry, but Ialo n e w as in apo sitio n tocollect and lay befo re yo u tho se matters o f histo ry, particularbj w

’

ula


regard to the Lo ndo n Ele ctrical Society. As to the pho tographingof the se curious handbills, that had be e n sugge ste d to me by theSecre tary, and w hen yo u se e my addre ss in prin t I have n o do ubtthey w ill accompany it .

Mr. LATIMER CLARK : There is o n e duty w hich w e must n o t

omit to perfo rm. The So ciety o f Te legraph Engin e ers is as w e

kn o w mo de lled upo n the law s of the In stitutio n of Civil Engin e ers.

We have re ce ived the greate st kindn e ss, courte sy, and assistan cefrom them : they have le nt us ahe lping-han d in many w ays

,but

abo ve allw e are indebte d to them fo r the co n tinued use o f the iradmirable ro om

,w hich they are so libe ral as to place at our dis

po sal w hen ever w e require it. I fe e l it is on ly n ecessary to propo seavo te o f thanks to the Presiden tand Co un cilof that In stitutio n toen sure its be ing cordially se con ded and carrie d by acclamatio n .

COLONEL STOTHERD : I rise to se co nd the propo sitio n,and I am

quite sure the kind perm issio n to use this ro om has co n tribute dvery much to the pro sperity o f this So cie ty.

THE PRESIDENT : I can e specially from this chair ask you to

ho ld up yo ur hands in favour o f this vo te , for this is n o t the first

So ciety ho lding its me etings here o f w hich I have had the ho n o uro f be ing pre siden t. Fo r many years past the Me teo ro logicalSocie ty hashe ld its meetings un der this ro of, and they co n tin ue todo so stillthrough the kindn e ss o f the Co un cil of the In stitutio n of

Civil Engin e ers. Tho se w ho approve of the vo te o f thanks to theIn stitutio n w ill be go od e n ough to ho ld up the ir hands, and I amsure it w ill be unan imous.

The mo tio n w as carried unan imously,and the me e ting w as

then made special fo r the purpo se of re con sidering Rule XII . It

w as reso lved that the Ballo t fo r the admissio n of can didate s shouldtake place in future at the first Ordinary Gen e ralMe eting in eachmo n th in place o fat every me e ting as hitherto .

The Forty-second Ordinary Gen eral Me e ting w as he ld on Wed

n e sday , the 26th January, 1876, Mr. C. V . WALKER,F.R .S.


The discussio n o fMr. C . Fle e tw o od’s paper

,

“On Un de rgroundTelegraphs— The Lo ndo n Stre et System ,

”w as re sumed by

Mr. ALEXANDER J. S. ADAMS , w ho said : The paper read tw omee tings sin ce po ssessed many po in ts o f in tere st, but few that w e relike ly to e licit di scussio n . At the same time it appears to me thatsome such pape r had be come mo st de sirable . W e have n o com

plete and co n n e cted acco un t o f the Lo n do n stre e t w o rk o f the past,but here is abasis upo n w hich w e may fo rm progre ssive comparison s

,and in this light the paper is o f value . Much might

,ho w

ever,have be e n added to ren der the paper mo re comple te than it

is. Fo r instan ce, the metho d fo r lo calising damp and m inute

faults ; spe cime n s o f actual faults w ould have be e n particularlyinteresting, fo r I do n o t think afault in covered w o rk can o ccur

w itho ut teaching its le sso n . Some men tio n might have be e n madeabout earth-curre n ts and o ther strange fo rces w hich w ould hardlyfail to pre se n t themse lve s upo n so exten sive asystem .

Lo oking at un de rgro un d te legraphy in its en tire ty tw o importantquestio n s pre se n t themse lve s. The o n e ,are the capabilitie s o f thepre se n t system and the succe ss achieved comme n surate w ith the co st

and the fact that this system has be en deve lop ed upo n the expe

rience s o f n early thirty years ? I may be co rrecte d, but I be lievehat an ew lin e in the heart o f Lo n don w o uld co st upw ards o f

2,000l. per mile , w hilst I do n o t kn o w any un de rground lin e

,ex

cept comparative ly n e w w o rk,that has n o t so o n er o r late r proved

expe n sive ly trouble some .

Again,do es the unde rground system

.

o f to -day bring us anynearer aso lutio n o f the problem o f putting alllin e s unde r gro und ?To my m in d the que stio n o f supe rseding suspe nded w ire s has lo ngbe en o n e o f co nsiderable impo rtan ce .

24 UNDERGROUND TELEGRAPHS. [26th Jan .

In the se days o f automatic Signalling there are apparatus andfo rce ge n e rato rs o f the mo st comple te and co stly kinds— applian ce sprobably equal to anything required o f them for some time tocome— but to w hat purpo se are they if upon some me te oro logicalchange the in sulatio n o f suspe n ded w ire s is reduced to almo st n il,and the w ho le system rendered n o n -effective the reby ? It is

,o f

course,w e ll to make the mo st o f w hat w e have , and to impro ve

existing mean s ; but suspended w ire s are practically beyo n d the irtime , and it w ould be w ise to direct tho ught and en e rgy to wardsthe productio n o f something e lectrically mo re co n stan t. Guttaperchao r indie -rubbe r are hardlyavailable fo r the purpo se . Guttaperchamay live to aco n siderable age un der certain co n ditio n s

,

but ho w‘are tho se co nditio n s to be provided and main tain ed

In taking up the que stio n o f co n structing a lin e e le ctricallymo re co n stan t than the pre sen t open lin e s I e n deavoured to placethe requireme n ts o f such alin e as fo llo w sIt sho uld be under gro und.

Simple in co n structio n .

Easy o f repair.

No t liable to fail .Fre e from jo in ts.

In su latio n con stan t.In ductive capacity low .

Capable o f carrying heavy po w e r.

Upo n trying vario us substan ce s like ly to fo rm an in sulato r fo rthe purpo se s of such alin e I w as satisfied w ith n o thing so w e ll asw ith asphalte , and to asphalte I dire cted my atte n tio n . It maybe urged that asphalte has already be en tried and has failed ; bu tI think it w as the co n structive prin ciple that failed and n o t th e

material . In o n e in stan ce , I be lieve at Amste rdam,a trenQ

w as made , and at in tervals alo ng it sectio nal plates or dia

phragms o f asphalte w e re fixed and pierced w ith ho le s,through

w hich w ire s w e re draw n and strain ed up. If w ith o ur beautifulcup in sulators the w ires suffe r from surface co nductio n w hatshall be said o f the se expo sed asphalte plate s ? In Englan dagain alayer o f ho t asphalte w as put do w n

,and in it lengths

o f old gutta-perchaw ire w ere imbedded, and upo n this an o the r

26 UNDERGROUND TELEGRAPHS . [26th Jan .

I am sorry so many po in ts o f in tere st w ere omitted from the

paper befo re us, fo r amo ngst o ther matte rs I sho uld like to havelearn ed from tho se able to judge if the un de rground system , as

it is,is comple te and asucce ss.

THE PRESIDENT : W e are much obliged to Mr. Adams for his

remarks as to the value o f asphalte . It reminds me o f days go n eby

,w hen Lo rd Dun do nald— the Lo rd Co chran e o f histo ry— made

some expe rime nts in covering w ire s w ith asphalte. His lordshiphad a large property in Trin idad w here bitume n abo unded

, and

various expe rime n ts w ere made w ith aV iew o f te sting its adaptability to te legraph purpo se s. I myse lf in 1853 tried some w ire s

co vered w ith thatasphalte I did n o t te st them in ascie n tific man n e r—ro ughly o n ly : in due course they pe rished. I be lieve Mr .

Latimer Clark has had some expe rien ce in the use o f asphalte ;an d he w ill perhaps be go od e n o ugh to state w hat the re sult w as.

Mr. LATIMER CLARK : In listen ing to apape r o n the Lo n do nstre et w o rk I fe lt I had be e n so lo ng disso ciated from such w o rk

that I w as hoping to learn rather than de siring to speak. The

pape r w as an able o n e and faithfully de scribed the actual existingsystem . It treated o n asubj ect o f great impo rtan ce to the Po sto ffice and to some exten t to submarin e te legraph compan ie s

, but

many in te resting po in tsappear to have be en o verlo oked,and I agre e

gen e rally w ith Mr. Adams as to w hat tho se que stio n s are . I ce r

tainly felt surprise that n o allusio n w as made to the use o f paraffinand asphalte as in sulating materials, and but very slight allusio nto india-rubbe r. I w as also in hope s that w e sho uld have had there sults o f some practical expe rie n ce w ith lead-cove red w ire s. The seare po in ts o n w hich w e requ ire info rmatio n

,and o n w hich I h0pe

w e shall ye t have some from tho se w ho have had expe rie n ce . Thereare some o ther po in ts

,viz . as to the be st size o f w ire

,w ith w hich

the que stio n o f inductio n is co n n e cted , and it w ould be in te re stingto kn o w w hat advan tage s re sult from using large r o r smalle r w ire .

W e are aw are , w ith refe re n ce to the rapid system ofautomatic signalling n o w coming in to use

,that the in ductio n o f stre e t w ires has

an impo rtan t influe nce o n the spe ed, and w e kn o w that o n e o f the

be n efits ofasphalte is that it decrease s the amo un t o f in ductio n,

be cause w e can use mo re o f that materialthan o f o thers w hich are

TH E LONDON STREET SYSTEM . 27

more expe n sive . In the early stage s o f un derground w o rk, w henw e be came first aw are o f the great amo un t o f re tardatio n w hicho ccurs w he n acurren t is se n t thro ugh gutta-perchaco vered w ire

,

I to o k out apate n t fo r e n casing gutta-perchaw ire s w ith asphalteto reduce the in ductio n . I mentio n this to sho w that e ven in tho seearly days the importan ce o f spe ed o f tran smissio n w as pre se n t too ur m inds.

With regard to asphalte , Lo rd Dundo nald’s ideaw as to co ver

co pper w ith akind o f natural asphalte w hich came from his exte nsive bitumen lake s in the island o f Trin idad. This mate rial failed

,

partly by reaso n o f its impurity and partly because it w as so so ft

that the w ire s readily fo rced themse lve s thro ugh it to the surface .

I then turn ed my atte n tio n to the very system w hich Mr. Adams

has men tio n ed to -n ight. I laid do w n some experimen tal w ire s atCamde n To w n o n leve l w o o de n troughs w ith diaphragms o f po rcelain o r slate at stated distan ce s, pierced w ith ho le s, and I carriedthe w ire s thro ugh the ho le s in little glass tube s, w hich w e re strungo n the w ire s. In to the troughs I po ure d liqu id asphalte . Thismadeat first apromising piece o f w o rk, and, as far as the te sting w e n t,appeare d qu ite perfect. I w as

,ho w eve r, led to abando n that from

circumstan ce s w hich I do n o t remembe r n ow, and I tried the fol

lo w ing plan , w hichalso did n o t succe ed. I had byme alarge quantity o f old gutta-perchaw ire w hich having be en originally o f impurequality had be come e n tire ly oxidised in to the resin ous state

,and

from w hich the gutta-pe rchahad broken in to little pie ce s like tobaccopipe s. I w as re luctan t to thro w it aw ay, so I laid up an umbe r o f

these w ire s in to alarge cable and co ve red them w ith acasing o f

canvas . I then placed the cable in alarge iro n cylinde r,five fe e t in

diame ter, and, exhaustin g the air from it,I go t ago od vacuum ,

and the n le t alarge quan tity o f w arm asphalte flo w in and fillthe

cylin de r. I n ext allo w ed the pre ssure o f the air to come upon it.This

,o f course , saturated the cable w ith asphalte

, and I found w he nit go t co ld a sem i-so lid mass, w ith the gutta-perchaw ire s in thein te rio r. The w ires had n o t be en affecte d by the heat

,and the in su

latio n w as fair, but it made anasty rope to handle ; and, thoughitw as co vered w ithase co nd surface o f sacking, it w as n everapproved,and w hen I left the service w as lo st sight of. These tw o in stan ces


co n stitute the o n ly acquain tan ce I have w ith asphalte , but I haveheard of its be ing exte n sive ly employed in Fran ce , and, as far as Ikn o w

,w ith some succe ss ; so that I think the autho ritie s in Englan d

w ould do w e ll to inquire in to the que stio n and to make expe rime n ts

fo r the purpo se o f ascertain ing the real value o f the material . 1

should have liked to kn o w w he ther indie-rubbe r could be used in

co njun ctio n w ith asphalte , because bo th asphalte and paraffin arematerials w hich w ill n o t injure indie -rubbe r. The n

, again , vul

can ised india-rubbe r w ould,I apprehend

,form w ith the se mate rials

avery durable system o f stre e t w ork w ith very lo w in ductivecapacity ; and I think further experimen ts might w ith advan tagebe made in this directio n .

The Fre n ch Atlan tic Company have , I learn , laid dow n n ear

Brest ado uble lin e of fifte en mile s of lead-covered w ire,man u

factured in Fran ce . I am sorry Mr. Varley, w ho has, I be lie ve ,examin ed the lin e , is n o t here to te ll us w hat the experien ce o f

it has be en ; but I be lieve that up to the late st accoun ts it had

lasted extreme ly w e lland the in sulatio n w as ve ry perfe ct. The

chief obje ctio n to it w as its expe n se ; butasamean s of preven tingthe gutta-perchafrom be coming oxidised lead is perfect, and I havese e n specimen s w hich appeared afte r tw en ty-five yearsas fresh toallappearan ce as n ew gutta-percha.

The effect o f lightn ing o n stre et w ires is apo in t o n w hich w e

might w ith advan tage rece ive info rmatio n . We allkn o w that intime of sto rms our be lls are rung by the inductive effe cts of thelightn ing ; but ho w freque n tly faults in stre et w ire s are o ccasio n edby lightn ing traversing the lin e is aque stio n o n w hich w e sho u ldlike to have the mo st recen t experien ce . The se are questio n s o n

w hich I hope this discussio n w ill e licit some in fo rmatio n .

THE PRESIDENT : Mr. Clark has called atten tio n to gutta-perchacovered w ire s, e n clo sed in lead . If there is any ge n tleman pre se n tw ho has had experie n ce in such w ork it w o uld be in structive tohear about it. Many years ago — in de ed , time passe s so rapidlythat I cann o t say ho w many years it is*— the South Easte rnRailw ay Company had aset o f gutta-perchaw ire s

, covered w ith

On reference to o ur books I find it was in July 1856. It co st 24l. per mile .

0 . V . W .

THE LONDON STREET SYSTEM . 29

lead,w hich w e re supplied to us by the Outta-pe rchaCompany.

They w ere laid unde r paveme n t, and w he n w e last saw them,

w hich w as some years ago , they appeared to be as pe rfect as w he nthey w ere first laid. Whe n th e o ffice se rved by them w as tran s

fe rred e lse w he re it w as to o expe nsive to pull up alo ng le ngth o fpaveme n t at Lo ndo n Bridge Inclin e , and tho se w ire s lie buriedthere at the presen t time . If the re isany ge ntleman prese n t co nn ected w ith the Gutta-pe rchaCompany w e sho uld be very glad tohear from him ho w this kin d o f w ire has behaved e lse w he re .

COLONEL GLOVER (re spo n ding to the Pre siden t’s in vitatio n )Mr. Ffin ch , w ho is pre se n t, has be e n lo nger con n e cte d w ith In diantele graphs than myse lf ; but o n o n e o ccasion

,be ing o n atour o f

in spectio n , I saw lying at Madras an imme nse quan tity o f leadco ve red go tta-perchaw ire . There could n o t have be e n less than50 to 100 to n s packed o n drums . I w as info rmed that it w as se n tby SirWilliam O’

Shaughn e ssey , an d had remain ed w he re I saw it

e ve r since its arrival . I had n o o ppo rtun ity of making amin uteexam inatio n , but I had the w ire o n se veral o f the drums cut

o pen , and in almost every instance the gutta-pe rchaw as broke nup in to to bacco pipe s,as Mr. Latimer Clark described. I can given o in fo rmatio n o f value w ith regard to the se w ires be cause I hadn o time to make any further exam inatio n ; but pe rhaps Mr. Ffin chw illbe able to te ll us mo re about it.Mr. EFINOK : I o nly kn ow that the gutta-perohape rished in the

lead cove rin g. Some o f this description o f w ire w as laid fromCalcuttato Beypo re , adistance o f fourte e n mile s, and o n o n e o r

tw o o the r short se ctio ns, and in every case it w as defective thro ughthe gutta-perchahaving pe rished, but I behave the fault w as in theinferio r quality o f the gutta-percha. The re w as, I kn o w ,

ave rylarge quan tity o f it sen t out from England.Mr. Lam aCLARK : Who man ufactured it ?Mr. Frmon : I cann o t say .

Mr. LATIMEB CLARK : Was it aleaden jo in t, w ith ashort tubeover it ?Mr . EFINOH : It w as o n e un ifo rm jo in t. Each drum co n tain e d

abo ut amile of w ire .

Mr. Lam aCLARK : There w as o riginally alarge quantity oi


Macnair’s tube s used in te leg raph w ire s, but yo ur de scriptio n do e s

n o t agre e w ith them .

Mr. SPAGNOLETTI : My expe rie n ce in undergroun d lin e s is n o t

very great, as far as mileage go e s. The lo nge st le ngth w e have o n

the Great We ste rn Railw ay is in the Paddingto n Statio n Yard ,and there are he re sixty w ire s in 4-in ch iro n tube s for adistan ce o f

am ile anda-half. The w ire s are in cast-iro n pipe s,and to get them

clear o f the ro ughn e ss in side befo re putting them do w n arym e r

w as made , w ith tw o discs o f ste e l about afo o t apart at the end, an d

by passing it up and do w n it clean ed them w e ll . The en d o f

o n e pipe fitted in to the so cke t o f the n ext, and w as filed roun d an dsmo o th to preven t the w ire s from be ing damaged as they w e re

draw n in . The pipe s w e re then heated o ver a large fire , a re st

be ing fo rmed byaco uple o f rails,and old timber w as use d fo r fue l ;

w hen sufficie n tly ho t they w e re dipped in to atro ugh o f coal-tar,

w hich had the effe ct o f japan n ing them in side and o ut and pre sen ting abeautiq y smo o th tube . They w e re the n laid do w n in a

tre nch and ceme n ted at the jo in ts and the w ire s pulled thro ughthem . In the case o f tun n e ls w e carry the w ire s e ither o ver o n

po le s o r in she e ting attached to the w all.The subje ct o f the pape r be fore us is an in tere sting o n e

, an d th e

te legraphic syste m o f Lo n do n is w o rthy o f apape r to itse lf. The

autho r has give n us ago o d deal o f in fo rmatio n about the se w o rksan d sho w s ho w Lo n do n is served te legraphically

,and the mileage

is much larger than I an ticipated. As the prese n t undergro un dw ire s se em to pe rish so so o n

,I fan cy there must be some mistake

o n the side o f suppo sed e co n omy in using the w ire w e have do n e .

Fo rme rly some w ire s w ere put do w n o fNo . 16 copper w ire , co ve redw ith gutta-pe rchato No . 4 o r No . 3

,and afte r having be e n do w n

fo r ape rio d o f fifte e n o r sixte e n years they w e re w he n take n up,

co n se quen t upo n the alte ratio n o f the the n route,fo un d to be in a

perfect state o f pre se rvatio n . The co n ductivity o f No . 16 co pperw ire was always le ss than that o f the w ire used

, and w hy aw ire ,No . 18

,o ffering as it do e s stillmo re re sistan ce

,is n o w ge n e rally

used , I can n o t understan d .

The w ire covered to No . 7 is much to o thin,and is very liable

in co nsequence to be damaged in be ing pulled thro ugh the p ipe s.

THE LONDON STREET SYSTEM . 31Q

The autho r advo cates the in crease o f un de rgroun d w ire s _hut in apape r by Mr. Ge o rge Pre e ce

,w hich he read in 1873, w as give n a

lo ng catalogue o f the disadvan tage s o f stre e t w o rk,w h ich w o uld , I

sho uld think, de ter any o n e from putting do w n mo re than co uld beavo ide d . The autho r do e s n o t me n tio n the disadvan tage s o f the

un de rgro un d system ; but, in the case of the Lon do n stre e t w o rk,the re is, I am to ld , o n e co n tin ual so urce o f damage from the heatfrom bakers’ ove n s, by w hich the insulatio n o f the w ire s is injured.

As aparalle l case , in the Paddingto n w o rk w e laid do w n the w ire sn ear to an un kn o w n steam-pipe

,by w hich they w e re co n side rably

affe cte d through be ing heated to an exte n t w hich almo st de stroyedinsulatio n altoge ther ; this w as ase rious source o f an n oyan ce , asw e co uld n o t alter the co urse o f the w ire s

,un le ss agreat o utlay

w as in curred, and w e had to de vise ascheme to pro te ct the w ire sfrom the heat o f the pipe .

It has be e n amatte r o f surprise to me that the Go ve r nme n t havelo st sight o f the Me tropo litan Railw ay fo r the ir un dergro undsystem,

be cause that railw ay fo rms ape rfe ct and se cure ro ute,and

run s thro ugh the mo st populo us parts o f Lo ndo n . It w ould requ ire o n ly ashort le n gth o f unde rgro un d w ire from the Po st-o tfice

to Aldersgate Statio n ; and, runn ing eastw ard,they w o uld ge t

dire ct commun icatio n w ith the Great Easte rn and No rth Lo ndo nRailw ays. Coming w estw ard , at King’

s Cro ss they could run

direct o n to the Great No rthe rn and the Midlan d Railw ays. At

Go w er Stre e t, Eusto n co uld easily be reached to ge t the w ire s o nto the Lo ndo n an d No rth We stern ; and at Paddington they co uld

jo in the GreatWe ste rn and Hammersmith and City Railw ay,and

the n to the w e ll-kn o w n Clapham Jun ctio n,from w he n ce they co uld

go an yw he re . Go ing ro un d the o ther w ay , from the City to theMansio n Ho use , they could jo in the South Easte rn

,the Brighto n

,

and the Londo n ,Chatham, and Dover Railw ays. I can n o t but

thin k that this ro u te w o uld be o f great advan tage , having te stingstatio n s so n ear and co n ve n ie n tly placed at the Me tropo litan Railw ay Statio n s. The re are manho le s in the tun n e ls w here amanco uld w o rk safe ly if a system w e re adopted o f putting the w ire sdo w n in atrough alo ng the side o f the w all an d w ire s co uld betake n up, re laid , and te sted very co nven ie n tly inde ed.


With regard to acable co vered w ith asphalte , I made o n e o f

old,but go o d

,gutta-perchaco vered w ire s, w hich w e re o riginally

laid alo ng the Blackw elllin e . The w ires w ere w rapped in hemp,and aco ve ring o f can vas w as put o ver the hemp an d coatedo utside w ith Sto ckho lm tar

,and the w ho le w as the n passed

through asphalte . That cable is w o rking n o w . Some years agoI think in 1863— Mr . Do nald Nico l , w ho live d n ear Kilburn , hadan ideao f using Trin idad asphalte . He had it tried and laid do w nin blo cks seve n fe et lo ng

,w ith ado ze n w ire s in each blo ck . The

j o in ts in the w ire s, w hich w ere very n umerous, w ere made like apocke t co rkscrew — o n e w ire w as spirally tw isted, the o the r w as

straight,and the straight w as pushed up the spiral o n e so as to

give se veral po in ts o f co n tact. He sen t amode l of this to theParis Exhibitio n .

I sho uld like to ask Mr. Adams ho w he managed w ith re gardto his jo in ts, and w hat distan ce be an ticipated he can thread w ire sthrough asphalte . I am afraid he w ill find some difficulty

,an d

the n umber o f jo in ts must be very great inde ed, and co n seque n tlyn o t an advan tage to any system .

Mr. ADAMS then pro ce eded to de scribe by illustratio n s o n th e

board t he plan o f co n structio n propo sed by him. He said : Theco n structio n o f alin e I have already de scribed ; and suppo sin g th etren ch w ith its co n cre te lin ing , and the w ire s are ready, the h o tasphalte is poured in to the trough o ver the w ire s from abo ile rstanding o r w he e led alo ng o ver the tre nch . The spo ut o r bo ile ro utle t w ould project in to the tro ugh, and this spo ut having aho tjacke t, the asphalte is de live red o n to the w ire s in quite aliqu idstate . Upo n the ho t asphalte run n ing short, the e nd o f the lin eis care fully co ve red w hilst an o ther batch is be ing prepared

, w hen ,afte r placing aproperly co n structed fire -box over the end to me ltthe last laid asphalte , the o peratio n is co n tinued as be fo re .

Tho roughly me lting the e nd befo re commen cing to pour the freshasphalte renders the w ho le a co n tinuatio n and n o t ajo in t. Thisplan has succe eded upo n asmall scale

,and I co n sider it w o rthy

o fmo re exte nded experimen t.Mr. HIGGINS : Ho w do you me e t the difficulty o f the expan sio n

o f the w ire s by the heat o f the asphalte ?


in the in sulatio n should n o t be lo st sight o f. In the w ire s co n

n ecting o ur large tow n s more leakage o ccurs w ithin the first and

last tw o o r thre e mile s of alin e than in tw en ty o r thirty mile sbeyo n d. Taking

'

the system roun d abo ut Lo n don , the in su latio n o f

the w ire s de terio rate s more afte r coming to apo in t abo ut five m ile sfrom Lo ndo n than it do e s o ve r lo ng distan ces in the o pen coun try .

Smoke clings to the in sulators, and fogs, e spe cially in the n e ighbourho od of the Metropo lis

,bring do w n the average in sulatio n ofall

the w ire s to agreat exte n t. If undergro und w ork w ere substitutedin place o f open w ires over these se ctio n s the ave rage in sulatio nw ould be improved. I do n o t argue that an un dergroun d can e versupplan t an ope n system but it may pro ve apo w e rful adjun ct tothe latter. Be tw e e n large ce n tres o f business undergroun d w ire sw ould probably in time pay the ir co st, if acting as n o thing but asalternative route s : the impro vemen t in w orking and co st o fmainte nan ce w arran t open w o rk be ing replace d by them in the n e ighbo urho od o f and through the large manufacturin g to w n s. On

the se groun ds I agre e w ith Mr. Fle e tw o o d that the exten sio n o f

the unde rgro und system is de sirable .

Me n tio n has be en made o f gutta-perchaw ire s in clo sed in leadtubing. I have had n o experie n ce o f this, but I have had some

expe rien ce o f lead tubing in un de rgro und w ork. Some tw o o r thre eyears ago I had o ccasio n to make use o f from 100 to 200 yards ofcove red w ire ofan e w type , w hich w as in troduced and submitte dfo r experime n t. It consisted o f coppe r w ire co vered w ith co tto n .

This co tto n -covered w ire w as passe d in to alead tube , and me lte dparaffin poured allroun d it by some mean s kn o w n o n ly to the

in ven to r. When te ste d it gave capital re sults, paraffin be ing su chan exce llen t in sulator, w hilst the lead, chemically pure , w as suppo se dto be inde structable . On e hundred yards o f this lin e w as laid do w no n acircuit fitte d w ith direct w riters, and w o rked w ith an o rdinarycopper curren t. After be ing at w o rk thre e mo n ths the circu itfailed ,and the fault w as fo un d to be in this sectio n o f experime n tal

On be ing removed the lead sho w ed sign s o f having be e nattacked , and had in fact been eaten thro ugh in o n e o r tw o

in stan ce s by galvan ic actio n,due to some impurity o f the me tal,

or to some pe culiarity o f the so il. The tubing w as re turn ed to theinve n tor, and I n ever heard anything more abo ut it. If gutta

THE LONDON STREET SYSTEM. 35

perchaw ire en cased in lead tubing w e re employed to any greatexte n t o n alo ng circuit I sho uld at first sight be inclin ed to dreadthe effe ct it w ould have in te nding to lo w er the carrying pow e r o fthe w ire . The re tarding influen ce already fe lt from inductionw o uld be greatly magn ified , fo r n o w averitable Leyden jar is

18

the gow n-pe rcha, and w ho se outer coating, the leaden tube , is in

To Mr. Adams’s plan I liste n ed w ith great in te re st. It se ems

struck me . The first part is, ho w are you to maintain such asystem as this ? Suppo sin g afault o ccurs, and w e must calculateupo n that eve n if the asphalte is allbut perfect, is the w iro to be

abando n e d, o r ho w are w e to ge t at it ? and again , if an e w w ire is

require d and has to be in the tro ugh, ho w are yo u to do it ? Willan e w tre n ch be required, o r in w hat mann e r are we to add to theexistin g has n e w w ire s as they are required ?Coal-tar w as me ntio n ed in co nn ection w ith gutta-percha, and

Mr. Latime r Clark state d that un der pressure he treate d some old

w ire w ith co sh-tar.

Mr. LA'I‘mER CLARK : Coal-tar pitch.

Mr. SIVEWB IGHT : Allthe experien ce I have had o f any fo rm

o f min e ral tar, or any o f the pro ducts o f min eral tar, is that the

so te is o ne o f the se products, and, although creo sote d timbe r isno w large ly employed, yet it is in variably found that w heregum-perchaw ires are brought in to co ntact w ith creo so te d timbe rade terio rating effect 18 produced upo n the gutta-pe rcha. Co nse

quently allte rm inal po les and boxing fo r offices are plain timber.

The PRESIDENT : I believe Mr. Latime r Clark,previo us to

re tirin g from his o fficial positio n w ith the Electricand In ternationalTelegraph Company, laid do w n line s o f undergroun d w ire s fromLiverpo olto Leeds. I should be glad to know w he the r tho se w ire s

are still in existen ce .

Mr. LA'rmEB CLARK : I kn o w they do n o t exist. I should

myse lf like to kno w the ir histo ry.

The PRES IDENT : Perhaps some ge n tleman can te ll us some thingabout them . I believe they w e re very go od w ires

,and w ere w e“

D 2


laid. Mr. Latimer Clark has refe rred to inductio n in gutta-pe rehaco vered w ire s. I w ould ask w he the r any o n e pre sen t is aw are o f

the re sult of the late Mr. Hearder’

s experime n ts at Plymouth . Mr.

Hearder w as e n tirely blind ; but he carried o ut e lectrical experime n ts almo st equally w ell w ith tho se w ho have the use o f the ireyes ; and he w as much m ixed up w ith the expe rime n ts o n the

Atlan tic cable as it lay at Devo nport after the first un succe ssfulattempt to lay it in the Atlan tic. The in co nven ien ce o f in ductio nw as the n made man ifest o n avery large scale for the first time . I

have by me specimen s o f Hoarder’

s w ire,in w h ich he ho ped to

reduce the inductio n by in creasing the distan ce be tw ee n the w ire

and the gutta-percha; to accomplish this the w ire w as co veredw ith w o o lle n o r co tto n thread o f vario us thickn e sses. I believe there sults w ere n o t e n couraging ; but I am n o t aw are to w hat exte nt

experimen ts had bee n tried w ith it. Ifany o n e co n n ecte d w ith thefirst Atlan tic cable is pre se n t he might be able to te ll us w hat theissue w as. Co lo n e l Sto the rd, w ho has had great experien ce w ithtorpedo e s, for w hich buried w ire s are employed, may be able togive us some in fo rmatio n o n this subject.Co lo n e l STOTHERD , R .E . I am afraid there is little that I can

te ll yo u o n the subject unde r discussio n , but I may refer to the use

made o f unde rground te legraph lin e s during the de fen ce o f Parisagain st the Ge rman Army in 1871 . There are an umbe r o f detached forts ro und Paris, at distan ces o f from 1; to 3 miles fromthe e n ce in te

,and fo rmingan advan ced lin e o f de fe n ce . With the se ,

te legraphic commun icatio n had be en e stablished previous to the

investmen t. From head-quarters w ithin the city,as ace n tre

,

lin e s of e le ctric te legraph w e re carried to certain po ints on the

e n ce in te , and to each o f the de tached forts. Each o f the de tachedfo rts had also alin e co n n e cting it w ith its n e ighbours, thus form in gacomple te lin e roun d the city, o utside the con tinuous lin e o f w orks,but co n n ecte d w ith the ce n tral statio n . Each te legraphic lin e w asdouble , and co n siste d o f an o rdinary air-lin e carried o n po les an dan in sulate d cable buried be n eath the groun d. This double lin e o f

commun icatio n w as in ten ded to se cure , as far as po ssible , certain tyo f signalling at alltime s. If the air-lin e w as in tercepted

, the

buried lin e might still remain efficien t, and if bo th w ere destroye d

THE LONDON s'

rasx'

r SYSTEM. 31

the re w as stillan alte rnative , though circuitous,lin e thro ugh the

commun ications to the right o r left of each o utlying fo rt.

lin e s w e re seldom in terrupted , and w o rked w e ll during the siege .

I do no t kn o w w hat precise fo rm o f e lectric cable w as used , buto n e that I saw subsequen tly at Paris w as similar to that made atSilverto w n— Gray’

s co re , cove red w ith tape . There w as n o specialcare employed in laying this— in fact, everything w as very roughit w as simply buried , w ithout troughing

,sufficie n tly dee p be lo w

the surface to se cure it from the explo sion s o f she lls .

As applied to to rpe do w o rk, I do n ot think there is much I

can te ll yo u w hich w ould thro w light o n the subject. Some

curio us results w e re ho w ever o btain ed in the co urse o f ase rie s o fexpe rime n ts o n the firin g o f fuzes thro ugh half-mile le ngths o f

e lectric cable laid side by side on the groun d at Chatham in 1870.

These w ere at first attribute d to in ductio n , but subsequen t trials,under differe n t co n ditio ns, gave probably mo re re liable info rmatio n .

This formed the subje ct o fapaper fo rwarded to the Secre tary, andw hich w illn o do ubt appear in due course in our Journal.“

Mr . G. E. Passe s : The principal object o f the pape r w hichw as read some mee tings ago w as to explain the pre se n t Lo ndo nsystem o f te legraphs ; and that be come s aque stio n w hich is n o w

m o re than eve r impressed upon our minds,espe cially o n acco un t

of the late sn o w -sto rms. It is n ow, w ithin afe w days, te n years ago

w he n Lo ndo n w as comple te ly cut o ff from the re st o f the w o rld.

I remember it ve ry w e ll indeed , and had go od cause to do so .

In January, 1866, the w ho le o f our lin es thro ugho ut the co un tryw ere broke n do w n . Commun icatio n to Edinburgh

,Glasgo w , and

o the r place s w as carried on by the first lin e available ; that w as

the so uthern lin e . We w o rked to the n o rth by o ur w ire to Glo ncestm' and B irmingham. So , again , in the case of the breakdow n of the last tw o o r three days, w e have be e n w orking fromLondon to Edin burgh, Live rpo o l, &c. ro und by the w est o f

Englan d. We m ight as w e ll w o rk from Brest o r Halifax. Thispo in ts to the fact that, o n the o ccurre nce o f sn o w ~sto rms o r heavy

gales o f w ind, the te legraph commun icatio n o f the co un try isliable to serio us in te rruptio n . It sho uld n o t be aque stio n of

VadaProceedings , N o . XII ., page 410 .

as UNDERGROUND TELEGRAPHS. [26th Jan .

finan ce,o r commercial busin e ss, but it is aque stio n o f the pro s

perity o f the coun try. You require abso lute certain ty that thete legraphic commun icatio n shall be main tain ed un impaired. I speakmo re as o n e w ho has had to do w ith main trunk lin e s w hich arese cure from the even tualities o f sn o w and w ind. With regard tothe Po st-o ffice te legraph service , w e are gradually coming to w ardsthat po in t. Some years ago allo ur lin e s came o ve rground by therailways to the Lo ndo n statio n s— to Euston Waterlo o , Shoreditch,&c. No w w e are gradually exte nding the main trun k lin e sun derground from the Gen e ral Po st-o tfice to po in ts outside thecourse o f the Lo ndon traffic. There w as adiagram here o n a

former o ccasion w hich sho w ed that. On the eastern side w e n o w goto Stratfo rd. Sin ce that diagram w as made w e have carried out a

n e w system of underground w ork as far as Stratfo rd fo r the

Eastern traffic ; and in co n n ectio n w ith the German submarin ecable s w e have , I think, tw e lve w ires acro ss the North Sea. The

same system has be en exten ded to the So uth Eastern Railw ay inre spect o f the con tin en tal traffic ; as regards the Lon do n and No rthWe ste rn Railway w e have fo ur o r five mile s to Kilburn ; w hile toHoun slo w w e have the main po stalroute w hich w as laid do w nabout tw o yearsago . In alldire ctio n s the te nde ncy is n o w to clearaway from the stre ets o f Lo n don allthe o ver-house w o rk and putour w ire s safe ly and quie tly undergro und— thus giving be tter in sulatio n , greate r facility o fw o rking,andgreate r fre edom fromaccide n t.Mr. Latimer Clark made refere nce to the old e lectric te legraph

w ires w hich w ere laid in 1853. The Ele ctric Te legraph Companylaidaserie s o f e ight w ires do w n the Lo ndo n and No rthWe ste rn l in eto Man che ste rand Liverpo o l. [Mn LATIMER CLARK : An d Le eds }The se w ires w ere laid alo ng the railw ay. They w ere No . 16 copperw ire co vere d w ith gutta-perchato No . 4 gauge , taped and tarred.

Mr . LATIMER CLARK : What w as the state o f the w ire s w he ntaken up

— the better part ?Mr. PREEOE : There w as n o be tter part, it w as allequally bad.

Mr. LATIMER CLARK I kn o w the cause of failure w he n they go tto Watfo rd . It might be in tere sting to the me e ting to hear it.Mr. PREECE : I think the re is alittle bit left in the Rugby yard.

It w as en tire ly from expo sure to the sun and bad w o rkman ship .

Mr. LATIMER CLARK : Was the w ire itse lf go od w hen taken up

m e ] THE LONDON STREET srsrxm. 39

Mr. Panama: We kn o w that w ires badly treate d be fo re they areput do w n must in variably be bad w he n take n up. Gutta-perchaw illno t stand o pen -air w o rk unde r any con ditio ns. Subsequen tlyto the se w ires be ing laid, in 1854 , ave ry in te resting w o rk w as

carried out w ith gutta-pe rchaw ire s in asphalte,under Mr. Latimer

Clark, n ear Mancheste r. The w ire s w e re led through an in sulato r,

and the troughing was filled w ith asphalte ; the tro ughing w as

suppo rted o n posts in the o pe n air,but thro ugh the actio n o f the

sun the w ires failed. That w as o n e of the earliest atte mpts I kn o wof the applicatio n of asphalte for the in sulatio n o f w ires. Abo utthe same time Mr. New man , o f the No rth Weste rn Railway

,applied

asphalte and tar to the w ires leading thro ugh the Lime Stree ttun nelat Liverpo ol, and tho se w ire s are stillgo od.

The n ext questio n is w ith regard to old buried w ire . I havesemi some of the old cable that carn e from Dover w hich w as laiddow n in 1850 in co nn e ctio n w ith the first cable , but my kn o w ledgeprevio us to that is n o t very great.Mr. SPAGNOLETTI referred to the en ormo us co nven ie n ce w hich the

Me trOpolitan Railw ayand its station safiord for carrying the underground w ire s o f the Po st-o ffice right througho ut Lo ndo n . We have

,

I belie ve,o n the Metro po litan Railw ay some fe w m iles o f w ire

,but

it has n ever be e n fo und de sirable to in crease the amoun t. The old

Electric Te legraph Company, w hen I first remembe r it, w en t in fo r

go o d so lid w ire . They use d it at that time do w n Pen to n ville Hill,

and it was laid do w n as far back as 185 1-2. That w as No . 4

gauge and 16 gauge co ppe r. At prese n t w e are using the smaller

w ire called N o . 7. The old w ire w he n taken up w as found to beperfectly go od. The No . 7 is very small and very liable to injury

,

and its durability un ce rtain .

With regard to the exte nsio n of the un de rground system,inas

much as w e require great con ducting po w e r it is unde sirable to use

such ve ry small w ire as that,and I ho pe n o w w e shall be able to

use a larger size . The re w as an o the r po in t me n tio n ed, viz.

the in co n ven ien ce of baker’

s ove n s in the Lo ndo n stre e t w o rk .

N o w, there is no pe rso n w ho has to do w ith stree t w o rk w ho

do es n o t lo o k out fo r the bake rs’ shops in this survey, and hekno w s just w here n o t to take his w ire s. In Lo ndon w e make a.

circuit under the stree t itself w here w e come to bakers’ e ven s. W


last po in t I w ill refer to is w ith referen ce to the use o fasphalte , tar,bitumen

,min eral products, & c. No w

,I be lieve coal-tar is about

the very w o rst thing that can po ssibly come in con tact w ith guttapercha. If you dip abundle o f gutta-perchaw ire s in to coal-tar

the in sulatio n w ill go do w n fifty pe r ce n t. very so on ; Ifyou leave itperman e n tly in co n tact w ith coal-tar the insulation w ill go off

e n tire ly in the course o f time . I have tried many experime n tsmyse lf and have see n o thers carried out, and, though coal-tar is a.

pre servative w ith regard to iro n w o rk , ye t w ith regard to guttape rchait is quite the reve rse . Sto ckho lm tar is preservative , butit reduce s the in sulatio n , although it preserves the gutta-pe rchalo nger than w ould be the case w itho ut w ate r ; but coal-tar is abo utthe ve ry w o rst thing you can po ssibly apply.

Mr. ADAMS : I beg permissio n to reply to o n e o r tw o po ints thathave be e n raised. Any fault in o n e asphalte lin e w ould probablyaffe ct the w ho le . If you lay do w n an asphalte lin e there should beasufficie n t n umber o f w ire s to remove the n e ce ssity fo r additio n s,and I be lieve if w e had eve n tw en ty such w ire s run n ing thro ughthe co un try to -day the system w o uld be practically w o rth“

tw ice itspre sen t value . I w ould use asphalte alon e , and n o pitch o r tax: If

pitch is used it should o n ly be as acovering over the asphalte the

ho t pitch w ould flow in to the po re s o f the con cre te . No doubt thebe st kin d of asphalte should be used fo r this w o rk, but my o w n

expe rime n ts upo n various asphalte s are as ye t in comple te .

Mr. LATIMER CLARK I hope I shall n o t be understo od asre comme n ding the use of coal-tar. I kn o w it is fatal.Mr. FLEETWOOD

,in replying to the discussio n , said Whe n

the paper w as read Mr. Varley re fe rred to the practice o f cuttin gand pricking w ire s

,stating that w he n he w as Engin e er to the

Ele ctric and In te rnatio nal Te legraph Company the me n w ere fo r

bidde n to do it under pain o f dismissal . Altho ugh this o rder mayhave be en issued the bad habit has co n tinued till ashort time ago .

The small galvan omete r used fo r fin ding w ire s w as place d o n thetable w he n the subje ct w as last be fo re the So cie ty. It is thatgen e rally used by the Gen e ral Po st-o tfice fo r te sting w ith Wheatsto n e

’

s bridge . Mr. Varley, alluding to it, said he bro ught o ut asmall in strume n t called “the w ire -finder in 1853

,by w hich it

w as easy to distinguishany w ire that had n ot be en marked. I stated

[9th Feb.

The Fo rty-third Ordinary Gen eral Me e ting w as he ld on W edn e s

day, the 9th February, 1876, Mr. C . V. WALKER,

President, in the Chair.

The PRESIDENT said : The autho r o f the pape r w hich is to beread this even ing be ing abroad, the Se cre tary w ill read it, omittingcertain page s o f mathematical fo rmula: w hich it w ould be scarce lyco n ve n ien t to read

,o r w hich w ould be un in te lligible to the m in ds

of tho se w ho heard them. With the exceptio n o f these the Se cretary w ill read Dr. Siemen s’s paper.

CONTRIBUTIONS TO THE THEORY OF SUBMERGINGAND TESTING SUBMARINE TELEGRAPHS.

BY DR . WERNER SIEMENS.

The starting po in t o f submarin e te legraphy is to be fo und in thesubte rran ean lin es co n structed in Prussiaduring the years 18471852. Be fo re that time

,it is true , attempts had be e n made to

in sulate w ires w ith glass tube s, caoutcho uc, &c.,fo r use as un de r

groun d lin es. Expe rimen ts o n a some w hat exte n sive scale byJacoby’"at St. Pe tersburg in the year 1842 deserve men tio n ; butthe se attempts failed.

In the year 1846 the author sugge sted to the Prussian Gove rnmen t the use o f gutta-pe rchaas in sulating material, this gumhavin g then recen tly become kn o w n in Europe . Its remarkableplasticity and in sulating property appeared to render it very su itable to the purpo se in que stio n , but n e ither the experime nts madeat Berlin n o r tho se carried o ut simultan e o usly in Englan d w e reatte nded w ith satisfacto ry re sults ; fo r the jo in ts o f the gutta-percha

P ogg. Annale n , vol. xxviii. p. 409.

SUBMERGING AND TESTING SUBMARINE TELEGRAPHS. 43

(w hich w as ro lled round the w ire ) gave w ay afte r ashort time .

At last in the year 1847 the problem found its so lutio n in acove ring machin e co nstructed and used by the author and Mr. Balaks ,by means o f w hich the gutta-percha, ren dere d plastic by heat, is

pressed round the w ire w ithout any seamin g.0

During the subsequen t years an exte nsive n etw o rk o f undergro un d lin es

,insulate d w ith guttape rchapressed ro und the co n

troduced in North Germany and Russia; although tho se lin e s w e re

save expe nse , w ere imbe dded in the groun d w itho ut external protaction , and at to o small adepth) they affo rded oppo rtun ity o f

gaining practical kn o w ledge for the co nstructio n and mamte nanceo f such in sulate d co n ducto rs and of studying the ir physical pro

perties. But it w as re se rve d fo r English e n te rprise to co nve rt thekn o w ledge and expe rie n ce thus gain ed to practical acco un t in asphere w here there w as n o co mpe titio n w ith cheape r o ve rgro un dlin e s

,that is to say, to submarin e te legraphy.

As early as 1850 Mr. Bre tt laid asingle gutta-percha-co veredco ppe r-w ire acro ss the Channe l be tw e e n Dover and . Calais. As

might be expected, this became use le ss : but in 185 1 Mr. Brett

substituted aco nductin g w ire in sulated w ith gutta-perchaand prote cte d externally by asheathing o f iro n w ire s. This w as the first

practicable submarin e cable .

N o great difficultie s w ere e n co un te red in laying the se cables inthe comparative ly shallo w w ate rs o f the Chan n e l. But w he n late rMr . Bre tt mldeavoured to lay such cables in seas of greater depth,he failed, be cause the fo rce s brought in to play in laying de e p-seacable s w e re n o t ye t recogn ise d, and co nseque n tly the n ecessaryprecautio n s had n o t be e n take n . The laying o f the first succe ssfuldeeprseacable betw e en Cagliari and Bo n e , in the year 185 7, inw hich the autho r had be e n reque ste d to take part, led him to in

vestigate the mechan ical prin ciple s o f cable -laying.

As is the practice in England, the cable is sto red in w ate r-tankso n board the cable -ship , w he re it is co iled in aco n tin uo us spiral ,and w he nce it is unco iled, w itho ut kinkin g o r be ing o therw ise

44 SUBMERGING AND TESTING [9th Feb .

impeded,over apulley fixed abo ve the m iddle o f the tank. If w e

suppo se the ve sse l to progre ss con tin uo usly w ith un ifo rm spe e d inastraight lin e

,le tting the cable drop from he r ste rn the great

le ngth o f the suspen ded cable admitting of our regarding it asperfe ctly flexible— every part o f the cable w ill sink to the bo ttomo f the seaw ith equal and co n stan t ve locity . Therefo re , the distan ceo fany part o f the sin king cable from the surface o f the w ate r must

be in proportio n to the time that e lapses from its leaving the ship.

If the spe ed o f the ship be co n stan t,this time w ill be propo rtio nal

to the horizon taldistan ce of the ship, and the cable must fo rm a

straight lin e to the bo ttom o f the sea. This straight lin e de sce n dsparalle l to itse lf. Le t every part o f the suspended cable de sce n dto the bo ttom by its w e ight in w ate r

,w ith the ve lo city v, the spe ed

o f the ship be ing 0,the n the angle a. be tw e e n the cable -lin e and

the ho rizo n is de te rmin ed by the equatio n11

(1) tan

If w e assume that for aportio n o f the cable de scending in thew ater paralle l to itse lf the distan ce is propo rtio nalto the fo rce

w,the w e ight o f the un it o f cable in w ater may be re so lve d in to

tw o compo n e n ts,o n e o f w hich, w co s a

,draw s the cable to w ards

the bo ttom in adirectio n at right angle s to the cable -lin e , w hilstthe o ther, w sin a

, draw s the cable in the dire ctio n. o f its axis an ddo w n the in clin e fo rmed by the w ate r

,by w hich it is suppo rte d.

The to tal actio n o f the latter tw o fo rce s is w lsin a,lbe ing the

le ngth o f the suspe nded cable ; o r,as 1 sin a. 11

,the depth of the

w ate r, the to tal strain , P = w k,is e qual to the w e ight o f the

po rtio n o f cable hanging from the statio nary ship vertically to thebo ttom .

If the cable is n o t re tain ed in the ship by frictio n,the strain P

is me t o n ly by the frictio n oppo sed by the w ate r to the sliding of

the cable in the directio n o f its axis. The amo un t o f this frictio ndepends upo n the co n ditio n o f the surface and upo n the diame ter

o f the cable . In heavy cable s sheathed w ith iro n, this amo un t

,

compared w ith the spe cific gravity o fthe cable , is so small, that the

much greate r po rtio n o f the strain P,o r w k

,has to be coun te r

ISM ] SUBMARIN E TELEGRAPHS . 45

balanced by friction o n board the ship,else the cable w ould desce nd

to o quickly and much of it be w asted.

In order to de termin e the n ecessary amoun t of this frictio nalresistance to be e stablished o n board the ship at any mome n t, it isn ece ssary to kn o w the depth o f the seaat any spo t w here the cableis to pass

,and to have adynamome te r indicatin g co n tin uo usly the

amo un t o f strain w ith w hich the cable leaves the ship. Furthe r,

as the ho rizo n talcompo n e n t o f this strain che cks the progre ss o f

the ve ssel, it is n ecessary to move the ship w ith afo rce sufficie n t to

ov ercome this resistan ce and to give the required spe ed . The refore

,w hen the cable-ship had be en pro vided w ith a brake o f

snfi cien t po w er and w ithadynamome te r w hich the autho r had co nstructed sim ilar to achain-balan ce , and w he n the cable-vesse l (he rengin e s be ing te e small to o ve rcome the strain o f the heavy cable )had bee n take n in to w by an o ther and stro nger steame r

,the n the

cable w as succe ssfully paid o ut be tw e e n th e previously men tio n edW '

Messrs . Lo ngridge and Bro oks? afterw ards made exte n sive t e

searches in to the the ory o f cable-laying. The mathematical part o fthe ir treatise is n o t to be disputed, and give s an accurate description of the curve fo rmed by acable suspe nded in an o bliquedirection in water, if paid o ut w ith strain upo n the sea-bed. But

the physicd part o f the w o rk, and the practical co nseque nce s draw nfrom it

,are ope n to grave objectio ns, as on e o f the first principles

liken fo r gran ted, w hich materially influence s the re sults,is in

correct Further, the w o rk is deficien t as regards aclear pe rce ption of the principal facto rs and alucid e xpo sitio n o f the re sults.

The fo rce s acting o n the falling cable are gravity and the

oppom forces of frictio n . Of the latte r there is first the slidingfrictio n , w hich acts in th e directio n o f the cable

,preve n ting its

slidin g do w n the inclin ed cable lin e , and se con dly the frictio nem bin ed w ith displacemen t o f w ate r acting in adirectio n pe r

The meditations abo ut the laying o f cables, exposedabo ve , represent the autho r’

8

46 SUBMERGING AND TESTING [9th Feb .

pe ndicular to the cable -lin e . The latte r fo rce is pro po rtio naltothe square o f the ve lo city ; the fo rmer pro po rtio nal to the ve lo cityitse lf. Lo ngridge and Bro oks suppo sed bo th fo rce s to be propo rtio nal to the square o f the ve lo city ; they obtain there fo rein co rre ct re sults, e spe cially in de termin ing the strength o f the

brake to be applie d o n board the ship . In stating the equatio n

tan a g, the autho r also assume d the ve lo city o f de scen t at righ t

angle s to the cable -lin e to be propo rtio nal to the force , but it w illbe sho w n late r that this is almo st exactly the case in tho se value so f the angle athat gen erally o ccur in cable -laying. The autho r’

s

suppo sitio n,that the cable forms astraight lin e if the spe e d o f the

vesse l be un ifo rm,do e s n o t depen d upo n the actio n o f the frictio nal

fo rce s. The cable alw ays fo rms astraight lin e o f such inclinatio nthat o f the tw o compo n e n ts o f gravity the o n e acting in the directio n o f the cable is co un terbalan ced by the sliding frictio n an d thebrake o n board the ship the o the r

,acting at right angle s to the

dire ctio n o f the cable , is co un te rbalan ced by the frictio n combin edw ith displaceme n t o f w ater. This give s equilibrium o fmo tion

,and

therefo re the mo tio n is un ifo rm .

In the fo llo w inglet abe the angle be tw e en the ho rizo n and the directio n o f

the cable ;gt be the angle be tw e en the dire ctio n o f the cable and

the directio n in w hich e very portio n o f the cableactually de sce nds ;

c be spe ed o f ve sse l ;u be co n stan t ve lo city w ith w hich the cable de sce n ds

vertically thro ugh the w ate r ;

1: be ve lo city o f fall w hen the cable-lin e is ho rizo n talw be w e ight o f un it o f cable in w ater ;I: be depth o f the sea;

lbe length o f the cable suspende d in astraight lin e inw ate r ;

p be frictio nal-force o r brake -fo rce by w hich the cable isre tain ed o n board the ship ;

SUBMARINE TELEGRAPHS. 47

le t 8 be slack,ratio o f surplus o f cable paid out to the pro

gre ss o f the ship .

Le t A’

B’

be the po sitio n o f the cable ; A B its po sitio n after theun it o f time ; and le t the po in t D o f the cable pro ce ed to H in theun it o f time ; le t the mo tion D H be resolved in to the tw o mo tion s

D E an d D E and the value o f D E be equal aand D F = b.

The n in bo th directio n s allfo rce s must balan ce each o ther to havethe actual ve lo city unvaried. Le t the co -efi cient o f the slidingfr ictio n be , for the pre sen t, r ; that o f the o ther frictio n 9. The ne qu ilibrium o f the force s acting in bo th directio n s D E and D Fo ccurs, if

(a) l. w . sin a— r . l. a—p = 0

(b) l. w . 00 8 a q . l. 62 0 .

Suppo se the cable to be paid out w ithout slack,the po in t D

w ou ld‘

arrive at C, the po in t H at K,making thereby B C B D

a.and angle GD K There fo re is GD F bise cted by D K.

If actually the po in t D has mo ved to H in stead o f K, then H K

repre se n ts the surplus o f cable paid o ut in the un it o f time, and

the re fo reE

C

Kis the value o f 8 . Thus w e have the fo llow ing

e quatio n s

4S SUBMERGING AND TESTING [9th Fe b.

as 6

DE a

The co efi cien ts r and q must be replaced by the abo ve -me n

tio n ed ve lo citie s u an d v. If the cable descends vertically w e

havear — w = O, u

If it descends ho rizon tally, w e have

e g— w = o ,

v J ig;

u,v,and w be ing co n stan ts o f the cable , de te rmin ed befo re the

cable is laid. The se are also the o n ly thre e cable-co n stan ts thatn e ed be kn o w n fo r the pre sen t purpo se .

Equatio n combin ed w ith the o ther fo rmulae , gives

therefo re

(2)1)

tan a. J co s ac J o o s a

This e quatio n is strictly true . But in p racticalcable-laying the

actualvalue ofagen erally is very small, and in this case equatio n

(1) give s sufficien tly exact re sults,~

as fo r small value s o faw e haveco s a. n early 1.

W e w ill first explain the co n seque n ce s o f (a) and (b) as they are

de termin ed by the exact value o f t; and afte rwards w e shall be

able to obtain simpler fo rmulae by in serting in stead o f 3 tan a.

‘U

0

W e have first the brake-fo rce w ith any required amount o f slack,

de termin ed by9.(3) 19 — 1071,

“w k (m 2

co s afo r smallvalue s o fa, the approximate value tan a.

so SUBMERGING AND TESTING [9th Feb

10’

36171 36071 36050 36047 36048 36048 36044

232 5 242 5 2448 2452

342 342 9 5290 7 117

3849 6

The se co n d table sho w s the co n side rable variatio n s o f brake-fo rcew ith adefin ite slack, the latte r be ing take n 10% and the depthstho se o f the Atlan tic.

c= 2’

8997 7690 695 9 9624

1799 3 1755 8 17033 1630 9 l215 °5

24310 3849 6

36465 57744II

The angle gt, w hich defin es the dire ctio n o f the actual mo tio n of

cable , is expre ssed by the equatio nc

(4) tan (bli p

w he n p’ = w h —

p ;

w h

finally 8 is defin ed by

(5) s figsin a— 2 sin 9

a

2

To facilitate compariso n w e n o w give the fo rmulae w hich , in steado f(2 are the re sults o fthe expo sitio n byL ongridge andB rookfi ,

describing them w ith our n o tatio n .

Fo rmula(2) is the same , but w e obtain in stead

o f (3) p w h — w hcg(1 s — co sa)

sin a

sin aco t gt 2 sin ’3

(4) tan sb

187 SUBMAR INE TELEGRAPHS. 51

Of (5) 3 2 sin ’3

The diffe ren ce be tw e en these fo rmulae and oursarises from the

suppo sitio n that the fo rce of sliding frictio n obeys the law o f

square s. This give s to o high value for p , if, the spe ed o f the

ve sse l and the depth be ing kn o w n facto rs, the cable is to be laidw ith adefin ite amoun t o f slack ; and o n the o ther han d this co n

sideratio n w ill give to o high value fo r 8 , if depth, speed,and brakefo rce be give n facto rs.W e shall n ext se e w hat modificatio n s are obtain ed w he n w e take

formula(1) instead o f omitting the factor co s a, and w hen

w e in this w ay e liminate the angle a, w hich is practically almo stinde te rminable .

First let us compare the value s o f a defin ed by the abo vementio n e d tw o formulm, several differen t values o f c be ing give n

TABLE III.

The comparison sho w s that if the spe ed be mo re than 8’

per

Second, o r abo ut 5 nautical mile s per hour, the numbers derivedfrom(1) may be taken as sufficien tly e xact for practicalpurpo ses.

1)Therefore in the fo llo w in g w e shall take tan a -

comitting

3

dimensio ns o f the o rder Then w e o btain

(3'

) p = w h(1 —ZP = w h(1

(“ itEquatio n (5) show s that the slack s is inversely p rop ortio nalto

E 2

52 SUBMERGING AND TESTING [9th Feb.

the square of the velo city, and that the first term o f the value o f s,

w hich is the more impo rtan t o n e , is prop ortionalto the diferen ce

u h p , that is to say, be tw e en the w e ight of the cable hangingvertically and the brake-fo rce .

When the cable is be ing paid o ut,avariation in the value o f 8

may o ccur from thre e cause s : alte ratio n in the depth h, o f thebrake -fo rce p , o r the spe ed c. If s be differe n tiate d acco rding tothe se thre e value s and divided by s

,w e obtain the per-ce n tage o f

the to talvariation o f 8 due to the thre e variation s in que stio n ;

11 if?de dh w h c

53

s h s

a"31 ”9

8

If,fo r in stan ce , h fathoms

,p c 8 fe e t,

w e have 8 01 0 10% therefo re2

9 9 and -

w h)3‘

c

- 2 1.

If n o w h, p , and c be each augme n te d by o n e -ten th of its value,

s in the first case varie s abo ut 99% of its previous value , in these co n d abo ut in third about giving instead o f

10% slackand

We se e therefore that the slack s varies in amuch greater ratio thanp , h, or 0, but that the variatio ns of 8 caused by those of h andp aremuch more considerable than those caused by variations of sp eed.

An o the r importan t deductio n is to be made from equationand th is is, that, un le ss the spe ed be ve ry small, in layingw ithout slack the brakeforce dep ends only up o n the dep th, and is

p rop ortio nalto it. This w as sho w n also in Table I . Vice versd

the dep th may be determin ed from the brake force , an d the an n exe dtable s w ill sho w ho w far this can be accurate ly effe cted, com

SUBMARINE TELEGRAPHS . 53

mencing w ith aspe ed o f 4 fe e t per seco nd. In Table IV .

brake-fo rce P is determin ed exactly by the formula

0 a

Wms)

Table V . show s the depths obtain ed from those values byfo rmula

P 1

w l— l v

2 u

w hich is approximate ly correct. Suppo se P is measured byexperime n t

, and the cable-co n stan ts u, v, w , are kn ow n , the depthis foun d by the Tables

TABLE IV.

0 = 4’

8’

10’

500 fathoms P = 901-8 901-3 901-2 901-2 901-2 901-1

1802-5 1802-4 1802-4 1802-4 1802-2

= s607-1 3605-0 36047 3604-8 3604-8 3604-4

5410-7 5407-5 5407-1 5407-2 5407-2 5406-6

TABLE V .

It (calculated)500 3 5001 500 0

10007 10001 10001

20001

30022 3000 -1 3000 2

It w ill be understo od, even from approximate formula, that thelaying o facable w ith adefin ite amo un t o f slack require s an exactkn o w ledge o f the cable -con stan ts, as w e ll as o f the depth andspe ed. We may assume the con stan ts of the cable to have be endistinctly ascertain e d before laying it, but the measureme n t of

depth and spe ed during the paying-o ut cann o t be performe d w ithan accuracy that w ill yie ld re liable results. The questio n n o w

remain s w he ther o r n o t it is po ssible to ove rcome these difficulties.

54 SUBMEBGING AND TESTING [9th Feb.

It be comes n e ce ssary to ask, Can acable be paid out w ithout

brake-force ? We should in such acase have

v (2u v)i

62

that is, slack is dependen t only upo n the sp eed, and n o t upo n thedepth.It w ould be po ssible to pay out w ithout brake-force and w ithout

slack if2u — v= 0 and v= 2u

,

that is, if the cable had co n siderable sliding-frictio n , but in thiscase it w ould be impo ssible to lay w ith Slack.Suppo se it w ere in tended to lay w ith 10% slack and w ithoutbrake -fo rce , then in the case o f the heavy Atlan tic cable the spe edmust equal w hilst the light cable o f Lo ngridge and Bro oks(having the co n stan ts v 14 04

,a: 110 24, w 00 6578) w ould

require aspe ed of Therefo re as

28

w e should be able by dimin ishing the specific gravity and in creas ingthe sliding fi ictio n to con struct acable that might be laid w ithoutbrake -force and w ith an amoun t o f slack varying w ith the spe ed ofthe ve sse l .There is still an other mean s, propo sed by the Author’

s bro ther,

Dr. C . W . Siemen s, o f ascertain ing experimen tally w hat brakepo w er is required to obtain adesired amoun t o f Slack. This iseffecte d by ke eping the spe ed co n stan t and increasing the pre ssureo f the brake until further in crease o f pre ssure is n o lo nger fo llow edby de crease in the ve lo city w ith w hich the cable is paid o verboard.The n w e have fo un d the brake-pow er n e ce ssary to lay w ithoutslack w ith agiven spe ed

,and it is easy to alte r the pre ssure o f the

brake un til any desire d Slack be obtain ed. But violen t mo tio n of

the ve sse l, combin ed w ith irregularity in the ve lo city w ith w hichthe cable run s out— an irregularity caused by the mo tio n as w ellas by mo re co n siderable in equalitie s in the sea-bo ttom— w ill o fte nre nde r eve n this expedie n t in effe ctive .

To obtain precise ly any de sired slack, the o n ly method w ill be


to pay o ut, w ith the cable , aro pe o r w ire havingapproximate ly thesame co e fficien ts u and r as the cable . If this w ire o r ro pe bere tain e d w ith sufficie n t brake-po w e r to be paid out w ithout slack,

the exact progress of the vesse l, eve n w itho ut the errors caused bycurren ts ; therefo re the brake has o n ly to be main tain ed un de r thepressure that w ill give any de sired ratio be tw ee n the ve locitie s w ithw hich the cable and the w ire are run o ut. The greate r expe n seincurred by the use o f the w ire w fllbe mo re than compen sate d fo r,be cause the w ire or ro pe paid out w ithout slack do e s n o t measure

the progress o f the vesse l in aho riz ontal direction , but the lengtho f the groun d passed over , and it the re fore defin e s the amoun t ofcable n e cessary to fo llow the in equalities of the sea-bo ttom w ithoutstrain upo n the cable ; and, as the usual amo un t o f 10% 15%Slack is ge n erally paid-out, to avo id the danger o f any such straino n un even ground, an d also the fo rmatio n of catenaries o f greatlength, it w illbe se en that the co st o f the w ire w ould be fully

co vered bypco n omy in the amoun t o f cable paid out.In orde r to in sure lo ng service the insulatio n o f asubmarin e

cable o r subterran ean co nductor must be perfe ct ; that is to say ,

the resistan ce o f the insulating coating must be equal to that defin edby acalculatio n based upo n the spe cific resistance o f the in sulating

de crease it may be assumed that in o n e o r mo re place s the w aterhas come in to communicatio n w ith the co nducto r through an opening in the insulato r. This may happen during manufacture o f

the cable , but ofte n it is first discovered durin g paying-o ut or sometime afte r the cable is laid. There fore

,during the manufacture ,as

w ell as during the layin g o f the cable,and afte r it has be e n laid

,

its physical pro perti es are submitted to co n tinuo us te sts. If the

existen ce o fafault IS discovered,it is very importan t to de te rmin e

its place o r its distan ce from the en ds o f the cable . Whe n the

cable is being‘

paid out it is ne cessary to arrive at this determination as sho rtly as po ssible

, to enable the ve sse l (provided the faultbe near the ship) to take in the po rtio n o f the cable re ce n tly paidout

, and co n tain ing the fault. The Autho r published in 1850 ‘ his1 pm . Ann . Bd. lxxix. p. 192.


the ory o f de termin ing the distan ce o fafault. The principle o f his

me thod is,to obtain by mean s o f tw o measureme n ts o f curren ts o r

re sistance tw o equatio n s, w hich w ill enable us to ehminate the

unkn ow n resistan ce of the fault, that is to say, the re sistan ce w hichis Oppo sed by the fault itse lf to the passage o f the e lectricity toearth ; it then be ing po ssible to defin e the ratio o f distan ce o f the

fault from bo th ends o f the con ducto r. The curren t may bemeasured at o n ce from bo th en ds o f the in sulate d co nducto r

,the

distan t e nd be ing o n ce in sulate d, on ce in co n n e ctio n w ith the earth ;o r the de terminatio n may be made by tw o measureme n ts from the

same e nd, the distan t e nd be ing in the first in stan ce in sulate d,in

the se co n d measureme n t put to earth. Measureme n ts o f curre n ts

be ing le ss re liable and mo re difficult to obtain than measureme n ts

o f resistan ce,the autho r subsequen tly modified his fo rmula

based upo n measuring curre n ts, substituting tho se fo r measuringre sistan ce s as so o n as he had succe eded in de termin ing adefin iteun it o f re sistan ce w hich could be easily reproduced , and had

employed this unit in the arrangeme n t o f an exact scale o f re sistan ce s Similar to aset o f w e ights ?Le t ab lhe the insulated conducting w ire , o f w hich the le ngth

and re sistan ce are kn o w n a: and y the distan ce s o f the fault from

aand b ; and z the re sistan ce of the fault. The n the distan ce w

from the e nd ais determin ed by the fo llo w ing equatio n s

(l. ) 593 1

—0

he n bo th ends are in the testing-ro om,and w and

y ”I

w 1 are the bridge -re sistan ce s, n o curren t passing through the

galvan ome te r.

from bo th ends, w ith the distan t e nd to earth, c the re sistan ce of

the w ho le w ire w he n faultle ss,

a,

from both en ds, w ith the distant end in sulated.

a, and b, be ing the resistan ce s measured

P ogg. An n . Bd. xc. p. 1. B d. xciii . p. 91. Bd. cxx. p. 512.

1' Outlin e o f the Prin ciple sand Practice invo lved in dealing w ith th e Electrical

Co nditio ns of Submarin e ElectricTe legraphs. ByW ern eran d C .W . Siemen s. 1860.


re sult. At the same time the influen ce o f polarizatio n at thefault is e liminated, w hich has o n ly the effe ct o f in creasing the

po ten tialat the fault, and the refo re acts like an in crease o f re

sistan ce o f the fault.The me tho d published by Mr. Jenkin is based upon simultan e ous

measureme n ts of the curren t passing through the fault and o f the

po ten tials o f bo th e nds o f the con ducto r. To obtain this, abatte ryand galvan ometer are in se rted be tw e en o n e end of the co nducto rand the earth, the o ther e nd o f the co nductor be ing in sulated.Be side s this

,bo th ends are co n n e cted w ith e lectrometers.

Mr. Je nkin ’s formulatake s in to accoun t the decrease o f curre n t

caused by the insulating coating,and,as in the case o f slight faults,

w hich are the mo st difficult to de termin e , imperfe ct in sulatio n iso f co n side rable influen ce

,Mr. Je nkin ’

s fo rmulaw ould be o f greatvalue , pro vided the simultan e o us measureme n t o f acurren t and

tw o po ten tials, in abso lute measure , at differen t place s, and w ithsufficien t accuracy to rende r the re sults re liable , did n o t preve n tto acertain exte nt the practicaluse of it.

From w hat has be en said,it follo w s thatame tho d o f de termin ing

faults can n o t give re liable results un le ss it e liminate s the ve ryincon sisten t resistan ce and the variable po larizatio n o f the fault.

Furthe r, in faults of great re sistance , o ccurring in lo ng co n ducto rs,it is n ece ssary to take in to co n sideratio n o r to e liminate the in sulatio n -curren t, that is to say, the abso rptio n-curren t, o r curren t o f

e le ctrificatio n,passing through the w ho le length of the in sulato r as

far as the cable is faultle ss. Again,the method must be capable o f

be ing carried out easily and quickly.

The Author trusts these co nditio n s are fulfilled by the fo llo w ingmetho d :

SUBMAR INE TELEGRAPHS . 59

Le t A B de n o te the faulty cable ; F po sitio n o f the fault,the

resistan ce o f w hichat the mome n t ofmeasuring z FG FH ;

AO P,measure o f pote ntial given to the cable-e nd by abattery

M d be tw e e n A and earth ; the n OH w ill be the “fall ” o f

the curren t passing through the fault and EF the pote n tial at F,if the o ther end of the co nducto r at B be in sulated. If w e assume ,pro visionally

, that the insulatio n o f the w ho le cable , excep t only ofthe fault, is perfect, w e shall have at B the po ten tialp . If a

straight lin e be draw n through G an d E,then D B w illbe the

measure of the po te n tial P'

, w hich shall give , w hen the cable isinsulated at A, the same po tential p to the fault F as it had previously by P from A. No w w e have the triangles 0 G

'

E DH’

E,

the refore ,P —

p : P’

.vand y den o ting the distan ce s betw ee n the faultand bo th ends o fthe co n du ctor A and B . As m+ y is the kn o w n length of thew ho le co nducto r, the po sitio n of the fault is perfectly de te rmin ed.Suppo se the resistan ce and po larizatio n to be the same in bothmeasureme n ts made o n e sho rtly afte r the o ther

,the results o f the

de termination are n o t influe n ced by them . No r doe s the impe rfectinsulatio n o f the co nducto r alte r the result, if the fault be in themiddle o f the cable o r n ear to it. Otherw ise , if the fault be n earer

to o n e end o f the co nductor, it is easy to apply acorre ction w hichamends the result (w ith an accuracy sufficie n t for practical purposes). It is easy to o btain sufficien tly accurate measures o f thepo te n tials if there is at each and statio n asen sitive m irro r-galvas om oto r to w hich , by shun t-circuits , any desired degre e o f se n

Siu'

ven ess may be given , ave ry high re sistance,o f some millio ns

of un its, and the means o f arrangin g abattery o f defin ed e lectromo tive force . If the se batterie s be co n structe d o f Dan ie ll’s ele

men ts w ith sulphate of zinc,and care be taken that the zin c po le s

con sist o f homoge n eo us mate rial and are w e ll amalgamated, and

that the liquids are o f un ifo rm stre n gth , the n the same numbe r ofsuch e leme n ts w illhave the same e lectromo tive fo rce provided the irte rnperature be constan t. If this is the case , and therefo re anyin crease o r de crease o f the e lectromotive fo rce by thermal curre n tsarising from the co ntact o f me tals and liquids o f differe n t tem

so SUBMERGING AND TESTING [9th Feb.

pe rature is avo ided the electromo tive force of such cells w illbe

indep enden t of their temp erature . No w, to bo th galvan omete rs may

easily be given the same sen sitive n e ss if each of them , toge the rw ith the high resistan ce , and abattery of determin ed numbe r of

e lemen ts, is in serted in circuit, and the shun t-circuit o f the galvan ome ter regulated so as to give the n eedle adefle ctio n agre ed upo nby bo th stations. In equalitie s o f resistan ce of the batte rie s andgalvan ome ters may be n eglected, if, as is assume d, the re sistan ce sin serted are very high . If the galvan ometers, brought to the same

sen sibility, are in serted be tw e e n the e n ds of the cable , &c. and the

earth, the ir deflection indicate s the po ten tial o f the place s o f

co n tact. A measureable alte ratio n o f the po ten tial w ill n o t beproduced by the shun t-circu it if the re sistan ce o f the batte ries ando f the w ho le cable is very small in co mpariso n w ith it.The measuremen ts required by this metho d o f dete rm in ing fau lts

are exe cuted as fo llo w s : Statio n A’ inserts any batte ry be tw e en

the cable an d the earth . As so o n as charge and po larizatio n havebecome co n stan t

,A and B record the ir galvan omete r-defle ctio n s,

and then statio n A in terrupts the co n tact of the cable -end w ith thefre e pole of the battery. Statio n B kn o w s this by the decrease o f

deflectio n of its galvan ome te r. No w it commun icate s by mean s o f

co n ve n tio nal impulse s o f curre n t the amoun t of deflectio n obtain edto station A

,and the n the equalfre e po le o f its batte ry is brought

in to co n tact w ith the cable-e nd. Station A n o w ann o un ce s,by a

signal agre ed upo n , w hether its galvan ometer sho w s greate r o r le ssdefle ctio n than that of statio n B . After this statio n B in crease s o rde crease s the e le ctromo tive force o f its battery un til A signals thatthe same deflectio n is obse rved . In order to co n tro l the re sults Aan d B may n ow alternate ly co n n ect the ir batterie s w ith the cableend and vary the e lectromo tive force o f the ir batterie s un til each o fthem pro duce s the same defle ctio n at the distan t e nd o f the co n

ductor. The e le ctromo tive fo rce s of the batteries may be varied byin creasing or decreasing the n umber of e lemen ts o r by co n n ectio nw ith shun t-circuits.

As may easily be se en,this me tho d e liminate s any inaccuracy

arising from the co nductive po w e r o f the in sulato r as lo ng as thefault is in the middle of the con ducto r o r n ear it. If the po sitio n


o f the fault be very exce n tric,the e lim inatio n is o n lyapproximately

comple te .

In stead o f e liminating,as in the preceding method, the e rro rs

arising from the physicalco nditio n s o f the fault be ing liable to so

great variatio n , by measuring from bo th e nds as n early simul

tan e o usly as po ssible— by w hich mean s the e rro r o r inaccuracyw o uld . be of the same amo un t fo r bo th measureme n ts and o n e

w ould compen sate fo r the o ther— the re sult may be attain ed byreducin g the po ten tialof the fault to zero . If o n e end of an in sulate d cylindrical conducto r be co n n ected w ith the po sitive po le , theo ther w ith an egative po le , o f galvan ic batterie s

,the free po le s o f

w hich are put to earth, the curve o f te n sion cuts the cable in themiddle , if the w ho le conducto r is homogen e ous and equally in su o

lated,and the e lectro-mo tive fo rce s o f the batterie s equal. By

insertin g and removing resistan ce s betw e e n the batterie s and theattached cable-en ds, the po sitio n o f that po in t o f the co n ducto rw here there is n o te n sio n may be varied at w ill. When this po in tco in cide s w ith the fault, n o curren t passe s by the fault to earth

,

therefo re the fault do e s n o t influe n ce the in ten sity of the curre n t at

the cable-e nds n or the fo rm o f the ten sio n -curve .

In figure 3, A B represe n ts the cable , 0 E and D F equal resistan ces, EA and B F re sistan ce s equal to each o ther, but variable ,G J Z K H the lin e of te n sio n w he n the cable is faultle ss. No w

,

ifafault o ccursatM,the po te n tial differen ce G C J E in crease s,

and the po ten tial diffe ren ce D H F K decreases. If,n o w

,


statio n A in creases its variable resistan ce B F un til the previo uslymeasured po ten tial differe n ce G C J E D H F K is re sto redat bo th statio n s, the do tted lin e G

’

M K’

is the actuallin e o f te n sio n,

and the re sistan ce in serte d in A and removed in B give s thedistan ce o f the tw o po sitio n s o f the po in t fre e o f ten sio n

,the refo re

also the measure o f the distan ce o f the fault from the middle o f the

cable . If the measureme n ts w e re accurate , the resistan ce in serte din o n e statio n w ill be equal to that remo ve d in the o ther.

The po ten tialdiffere n ce 0 G E J, as w e llas that o fD H FK,

may be measured as befo re by discharge s of aco n den ser, thecastings o f w hich are co nn ected w ith C and E and w ith D and F

,

o r by defle ctio n upo n asen sitive galvan ometer,the en ds o f the

co ils be ing con n ected by ve ry high re sistan ce s w ith C and E an dw ith D and F.

Hitherto w e have dealt w ith faults o f in sulatio n , in w hich it w assuppo sed that the co nducto r itse lf w as n o t damaged and w as co n

tin uo us from o n e statio n to the o ther but faults o f an o the r kin dmay o ccur. The co n ducto r may be broken in side the in sulatingco ve r

,o r the cable may be pe rfectly severed, in w hich case

,

almo st w itho ut exceptio n , the e nds o f the co nducto r come in co n

tact w ith the w ater. In the first case the distan ce from the fracturemay be easily determin e d by measuring the capacity o f the Leydenjar fo rmed by on e o f the tw o parts o f the cable , and by comparingit w ith the capacity o f the un it o f le ngth of the co n ducto r. Thiscan be do n e e ither by directly observing the deflectio n o f am irrorgalvan ometer, or, as sugge ste d by De Sauty and Varley, by se nding simultan e ously the charge o f the cable to be measu red and thecharge o f the conden ser serving as astan dard o fmeasure throughthe same circuit

,and w ith the he lp o f aWheatsto n e ’

s bridge o r

differe n tial galvan omete r o btain ing an adjustmen t that sho w s n odefle ctio n . The ratio of the bran che s of the bridge w ill o f coursegive the ratio o f the charge s.

These me thods, w hich are very convenien t in sho rt cable s,cease

to be sufficien tly accurate w he n the cable sare very lo ng. In the

first place to o lo ng time is n e eded to complete the charge o f the

cable ; se co n dly, the se n sitiven e ss o f the galvan ometers must be

reduce d to to o lo w astandard that they may measure the passage


o f the large quan tity o f e le ctricity accumulated in a lo ng cable .

The same obje ctio n o ccurs w ith De Sauty’s me thod, because , if the

galvan om eter is to o sen sitive,the charge-curre n t o f the co nde n ser,

w h ich is at first much the stro nger,drive s the n e edle ove r in the

co rrespo ndin g dire ctio n,w hilst the charge -curren t o fthe cable , w hich

flo w s mo re slo w ly,defle cts it afte rw ards in the oppo site dire ctio n .

The deficien cie s of the metho ds at pre sen t kn o w n may be

remedied in the fo llo w ing man n er — We de termin e the defle ctio nfrom the discharge ofaco n den se r o f kn o w n capacity charged by acon stant batte ry. Then w e employ this co n de n se r as astandardjar in repeate d partial discharges o f the cable , and finally w e

measure the nth discharge o f this jar. Le t 7c be the capacity o f this

stan dard-jar, the un it o f cable -length be ing take n as un it o f

capacity ; and let a: be the capacity o f the w ho le cable-le ngth .

Furthe r, le t P den o te the po ten tial to w hich the cable and theconde n se r are charged, P2 P2 P3 P

”the po ten tials o f the

cable , and of the co nn e cted co n den ser afte r the first,secon d

,

third nth discharge of the latte r. Finally

,le t aan d a

”be

the discharge defle ction s o f the con den ser at the first and n“dis

charge . Then w e have

P 3P1 = w + k t w

and

P

o r,asaand a

nare the galvan ome te r-deflection s co rresponding to the

charge s o f the stan dard-jar P and P“, we have

v7. z/‘

aj

It is much more difi cult to de termin e the distan ce ‘

of the fractureo facable if the end o f the co n ducting w ire come s in to co n tact


w ith the w ater. Gen erally, w he n acable breaks, the co n ductingw ire and the in sulating coating do n o t break in the same tran sve rsesectio n , so that e ither apo rtio n o f the w ire lie s un cove red in the

w ater,o r the w ire come s in to co n tact w ith the surroun ding w ater

through anarro w tube,o n ly imperfe ctly fille d w ith w ater. In the

first case,measuremen ts o f re sistan ce execute d cautio usly from the

land w ill ge n e rally yie ld sufficie n tly accurate re sults. But,be side s

the variable po larizatio n o f the faulty place , there is in this casean o the r cause o f erro r

,name ly

,that the ao-called earth-curren ts

almo st alw ays are to be found to agreate r o r le ss exte n t. Evenw hen there is n o auroraborealis visible at n ight, the se curren ts

(w hich must be traced to te rre strial o r co sm ical so urce s) o fte n

appear in cable s in co n tact w ith w ater at bo th en ds, and the irin te n sity can amoun t to that o f 6- 8 Dan ie ll’s ce lls. The autho rsucce eded in compen sating for the in fluence o f earth-curren ts upo nthe measuremen ts by co n n ecting the cable-bran ch o f the bridgew ith ashun t o f variable re sistan ce

,and w ith asufficie n t e le ctro

mo tive force to balan ce the earth-curren t. The balan ce w ill bee ffe cted w hen the bridge-galvan ometer indicate s n o curre n t.

Numero us obse rvatio n s upo n earth-curren ts w ere made by thisme thod

,to w hich the autho r w ill refe r at some o ther time . But

,

although w e may in this man n er avo id the in flue n ce o f earthcurren ts in measuring re sistance s, the re sult is n ever re liable , as itgive s o n ly the to tal re sistan ce o f the cable and the fault toge ther

,

an d do e s n o t indicate the re sistance o f the latter. Often the re sistan ce to tran smissio n o f the curren t from the con ductor to the

w ater is greater than the re sistan ce o f the en tire cable .

In cable s w here the distan t end is inacce ssible , w e can n o t o btainaseco n d equatio n , by mean s o f w hich w e m ight e liminate thevariable re sistan ce , and it is in this case be tter to measure thee lectro -static capacity o f the portio n o f the cable .


If the value of a l a(de te rmin ed by measuring simul

tan e ously the charge o f the cable and the resistan ce ) be substi

tuted, w e have

a3 z3

hen ce

As w e have P l 2 4a, the quan tity of charge o f the e ntire cablew hen . faultle ss, as w e have also P the charge q, o f the un it o finsulated cable ,

z = -<Pq

'

As by measuring the re sistan ce simultan e o usly w e have ascertain eda,and as I : a z

,the length lo f the broken cable is determin ed .

If z o and a l,the precedin g equatio n give s

lq = 4»l

g"

that is to say, ifacharged cable w hich is at o n e e nd con n ected w ithearth, w ithout resistance , be at the o ther e nd also conn e cted toearth, and w ithout re sistance , the n tw o-thirds of the charge re turn s

to the charging statio n,and o n e-third go es to earth at the distan t end.

Of course n o time must be lo st be tw e e n the removal o f thebattery an d the in sertio n o f the galvan ome te r (put to earth) ,because , during the time the cable remain ed in sulated, aco n siderable po rtio n o f the e le ctri city w ould trave l to the o the r e nd ; therefo re

,the discharge w ould be to o small. But if the change o f

con n ectio n is made at o n e and the same momen t (as effecte d byHehn holtz in the re sults obtain ed by this me tho d co rre spo n dve ry clo se ly, and are ve ry exact. If the co n ducto rs to be measure dare o f great le ngth, the re tardatio n o f the curren t in co n seque n ceo f the charge in troduce s e rro r. The refo re

,if this be the case

,the

pre ceding formulan e eds co rrectio n,o w ing to this re tardatio n o f

the curre n t,but the autho r has n o t as ye t succe eded in de te rmin ing

the n ece ssary co rre ctio n .

SUBMARINE TELEGBAPB S . 67

The PRESIDENT : This pape r is o n e w hich can o n ly be pro perlyappre ciate d by reading it quietly, w ith time to study the diagrams and formula, mo st o f w hich have n ece ssarily be e n passedo ve r. Fo r myse lf, I have n o perso nal familiarity w ith submarin ecable s, and therefo re sho uld n ot be justified in o ccupying yourtime by any remarks of my ow n . The paper comme nce d byreferring to the first cable w hich w as laid across the BritishChan n e l. It was manufactured fo r Mr. Read the e lder . I remem

be r se e ing the cable at Do ver“ It w as at that time scarce lybeliev ed that acable w as abo ut to be laid across the chan n e l ; andI have in my po sse ssio n at this mome n t— and it fo rms an in te re st

ing matter o f histo ry— ale tte r from Mr. Le w is Ricardo , the the nchairman of the Electri c Te legraph Company, asking me if it

really w as true that acable had be en made , and w as abo ut tobe laid across the chann e l ? There are several ge n tlemen prese n tw ho are acquain te d w ith the tw o chief po ints to w hich yo ur attemtion has bee n dire cte d , viz . the me chan ical o peratio n o f layin gcables and the e le ctrical ope ratio n o f te sting fo r faults ; and Iam sure the remarks o f those conversant w ith the se po in ts w illbe liste ne d to w ith great atte n tion and great patie n ce by the

Mr. WILLOUGHBY SMITH (respo nding to the Pre siden t’s in vita~

ti on ) said . As electrician to the Te legraph Co nstructio n andMainte nance Company, I have had alarge experien ce in submarin etele graphy, but I am at the same time happy to say my expe rien cein localising faults has been ve ry limite d . The pape r commen cesby stating : The starting po in t o f submarin e te legraphy is to befo un d in the subte rran ean lin es co n structe d in Prussiadurin g theyears 1847 and No w

, I que stio n w he ther, prior to 1850,

of subterranean lin e s in Englan d and o the r coun tries. The suc

cessful laying o ffire lin e from Do ver to Calais, in September 1850,was the germ from w hich submarin e te legraphy sprang.

Then , again , Dr. Sieme ns says : In the year 1846 the Autho rsuggeste d to the Prussian Go vernme n t the use o f gutta-perchaasin sulating material : this gum having the n rece n tly be come kn o w n

in Europe .

” Further on it is stated, that in 1847 the Autho r inr 2


co nj un ctio n w ith an o ther perso n co n structed amachin e by mean so f w hich the gutta-percha, re ndered plastic by heat, w as pre ssedroun d the w ire w ithout any seaming.

I have w ith me afew n o te s,w hich I should like to call atten tio n

to ; and, if I am w ro ng in anything,I hope the re are ge n tlemen

pre sen t to co rre ct me . I do n o t thinkanyo n e w ill dispute that it w asin the year

~

1843 t hat Dr. Mo n tgome rie tran sm itted the first sampleo f gutta-pe rchato the Socie ty o fArts. Sample s o f several article sro ughly made from gutta-perchaw e re exhibite d at the So ciety o f

Arts in 1844 . The first paten t in w hich gutta-pe rchais me ntio n ed w as obtain ed by Mr. Charle s Han co ck in May 1844 Fo r

certain improvemen ts in corks and o ther sto ppers.

” In 1845 an d

1846 pate n ts w e re obtain ed fo r m ixing gutta-perchaw ith allkn o w nand unkn o w n substan ces for allkn o w n and un kn o w n purpo se s.

The mo st importan t paten t o f the year 1845 w as that o f He n ryBew ley for manufacturing gutta-perchabo ttle s, tubes, &c. In his

spe cificatio n he says : The gutta-percha in aplastic state is putin to acylin der

,and apisto n w o rking in to this cylinder presse s the

gutta-perchaagain st a heated disc in w hich there are ho lesthrough w hich the gutta-pe rchais pre ssed in to acup, fi'

om w he n ceit passes o ut and roun d acore

,and de sce nds in the de sired tubular

form in to are ce iver o f co ld w ate r.

” This,n o doubt, w as the

germ o f the pre se n t tube and w ire -covering machin e s. In Feb

ruary 1848 Profe sso r Faraday called publicatten tio n to the e le ctricalqualitie s o f gutta-percha. In the paper un der discussio n Dr. Sie

men s says that in 1846 he sugge sted to the Prussian Gove rnme n tthe use o f gutta-perchaas an in sulating material. It is curious thatPro fessorFaraday co n sidering how carefulaman he w as— should

,

tw o years after, bring it befo re the public as an e w thing. I w ouldrefer you to ale tter o n this subje ct published in the P hilo sop hicalMagazin e fo r February 1848 . There w e find that the first paten t inw hich gutta-perchais me n tio n ed in con n e ctio n w ith e le ctricity is byCharles Han co ck, in May 1848, in w hich he says : Gutta-perchapreviously bo iled w ith muriate o f lime is passed be tw e en heatedcylin ders w hile ro sin is sifted o n

,or so lutio n s o f the tw o are made

and mixed This is employed w he re complete e le ctric in sulatio n isde sirable . In September 1848 John Lew is R icardo paten ted

1876 ] SUBMARINE TELEGRAPHS . 69

“Impro veme n ts in Electric Te legraphs and apparatus co nn ecte dthere w ith,

”o n e o f w hich w as “Laying o n e o r mo re w ire s be tw ee n

bands o f gutta-percha, and the n thro ugh apair o f gro o ved ro llersheate d by steam but he preferred to use acompo un d compo sedo f guttapercha, New Zealand gum, and sulphur. The Guttapa‘

cha Company had been , since early in 1848,e ndeavo uring to

obtain aperfect method of covering w ires w ith gutta~perchafo rtelegraphic purpo ses. In 1849 (I think in No vember, but am n o t

quite sure ) they comme n ced to supply the Prussian Go ve rnme n tw ith sulphure tte d gutta-percha cove red w ires. No w o nde rthe insulatio n was so o n destroyed , co nsidering the large quan tityo f sulphur they had mixed w ith the gn tta-pe rcha. In 1849 the

Guttao

percha Company comme n ced to manufacture the lin ew hich w as laid from Dover to Calais in 1850 ; and in 1850

Ern est Wern er Sieme n s pate n te d amachin e for co vering w ire w ithgutta-perchafo r te legraph purpo ses, w hich machin e w as much ihferior to tho se already at w o rk o n the Gutta-pe rchaCompany’

s pre

mise s. It w as in Septembe r 1850 that Mr. Read laid the w ire fromDo ver to Calais, and it soo n failed, as might have been expe cted.

I be lieve it is n o t ge n erally kn o w n that the sho re e nd of that w irew as compo sed ofaco pper w ire co ve red w ith co tto n , passed throughasolutio n o f in diarubbe r and e nclo sed in athick leade n tube . The

shore e nds w ere laid some days be fo re the gutta-perchaco veredw ire w as laid. I be lieve but fo r tho se shore ends the w ire w ouldhave lasted lo nger. Up to the time o fjo in ing w ith the w ire in thelead tube the cable lasted w e ll, but w he n w e arrived at the lighthouse at Cape Grisn ez w e co uld n o t ge t any signals, and in tryingnext day to remedy the evil the w ire broke .

The first chann e l cable w as laid in 1851 . In 1854 the Medite r

ran ean cable was laid be tw een Corsicaand Sardin ia, in some place sat adepth of 500 fathoms. Had Mr. Bre tt employed a steamer

insmw o f asailing vesse l to lay the o the r se ctio n from Sardin iatoAfricain 1855 I think he w o uld have be e n as fo rtunate as he w as

w ith the lin e betw e e n Sardin iaand Corsica, but by usin g asailin gvesse l he had n o co ntro l and co nsequen tly lo st the cable . It w as a

very heavy cable to attempt to lay at depths o f fathoms, butin 1857 Mr. New all succe eded in laying alight cable o ve r the same


Mr. C . F. VARLEY,F.R .S.

—This paper o n ly came in to my han dsthis mo rn ing, and tho ugh I e ndeavoured to ge t through it, andspe n t about thre e hours and ahalf over it, I have n o t succe eded

ye t in dealing w ith the w ho le o f the equatio n s in the pape r.

Neverthe less there are many po in ts I can deal w ith,and I am

sorry that it w ill be my duty to'

attack the paper from the tw o veryfirst lin e s. In the se it is stated, The starting-po in t o f submarin ete legraphy is to be foun d in the subterranean lin e s co n structe din Prussiaduring the years 1849No w I may .be permitte d to say that the starting-po in t o f sub

marin e lin e s w as to be found w hen this ce n tury w as in its te e n s,

at St. Pe te rsburg,by

,I think it w as

,Profe sso r S6mme ring (if

you co n sult Dr. Hame l’s little bo ok you w ill se e the particularsde scribed, as w e llas the autho rity w hen ce he derived his stateme n t),that some w here abo ut the year 1807 o r 1808 that Profe sso r in troduced to the Russian

i

Empero r a little subte rran ean lin e,w ith a

charge o f po w de r at adistan ce o f mo re than am ile . The Empe ro rw as to ld to take tw o w ire s in his han d, and w as in fo rmed that o nmaking them to uch the m in e w ould explo de : he did so

,and the min e

exploded . That led to agreat number o f experimen ts,an d w e find

w hen the allied gen erals w e re assemble d in Paris in 1815 the sam e

Profe ssor amused the English and Prussian officers and o thers bylaying his lin e acro ss the Se in e and firing charge s o f po w der o n the

o ther side . In 1818,I think I am co rrect as to the date

,Pro fe sso r

Somme ring had ate legraph at w o rk,and so co nfide n t w as he o f

succe ss w ith it un der the seathat asubmarin e cable w as o rdere d tocon n e ct Cro n stadt w ith St. Pe tersburg. This I think w as the first

and the pare n t ideaof submarin e te legraph cable s fo r se n dingmessage s.When w e come to the practical realisatio n o f submarin e te le

graphy I think the Electric Te legraph Company w ill be able to

claim prio rity o ve r eve ry o n e e lse . In the year 1847 Mr . Charle sWe st brought to us w ire s in sulated w ith in dia-rubber

,he having

previously e stablishe d commun icatio n betw e e n Daw lish and Te ignmouth through the tun n e l, by mean s o f such w ire partly buriedin the g roun d and partly o n land o r the side s of the tunn e l. I

w as at that time in the south o f Devo n , and, the w ires be ing


expo se d to the sun and open air,the in sulatio n w as ve ry bad.

Mr. We st,in October o r No vember, 1847, thought he sho uld like

to try the po ssibility of w orking unde r the seaby mean s o f an

india-rubber covered w ire , and my superior officer,Mr. Re e ce

,

Mr. We st,and myse lfarranged to te st it by mean s of some o f the

w ire w hich w as afterwards e re cted o n the lin e . A boat w as go tready : Mr. We st

’s man w as left o n shore w ith asingle n e edle

in strumen t, and Mr. We st, Mr. Re e ce , and I w en t in the boat.

We paid out this w ire by han d : te legraphed through it and te stedits in sulatio n . We the n re turn ed to the sho re , I be ing very seasick

,fo r I must con fe ss it w as my first trip o n the briny.

”

That w as I think the first time asignal w as sen t under sea-w ate r.

Next, in the year 1848, the Admiralty de sired that the ir te legraph circuit, w hich exte nded from Whitehallto the VictuallingYard at Go spo rt, should be exten ded o n to Po rtsmo uth. No w

, I

may tellyo u that as early as the year 1846 they had expre ssed asim ilar w ish to Me ssrs. Co oke and Wheatsto n e

,be cause the

semapho re te legraph be tw e e n Po rtsmouth and the V ictuallingYard w as o ften obscured by fog, w hile the electric te legraphbetw e en the V ictualling Yard and Whitehall remain ed in pe rfe ctw orkin g o rder. I remember, o n taking charge of the Lo n do n andSouth We ste rn Railw ay te legraph, finding to my surprise atGo spo rt abo ut am ile o f w ire in a leaden tube . The w ire w as

covered thickly w ith co tto n and in sulated w ith amixture o f pitchand re sin

,it be ing in tended to lay this w ire from the Victualling

Yard to Po rtsmouth Do ckyard ; this, how ever, w as n ever carriedout

,although the re w as an attempt to lay a submarin e w ire

of mo re than amile in le ngth. In 1848 w ires were laid acro ssthe upper po rtio n of the harbo ur, and tho se w ires w ere in sulatedin adifferen t man n e r as an experimen t. Mr. Willoughby Smithhas to ld yo u that Mr. R icardo paten ted apro ce ss o f in sulatingw ire s be tw e en tw o bands o f gutta-pe rcha. Half-a-doze n w ire sw ere laid un iformly distan t upo n ashe e t of gutta-pe rcha

,an o ther

she e t o f'

ho t gutta-perchaw as then placed ove r them,and the

w ho le pre ssed together. Tw o such ribands w ere laid do w n . as alsoaleade n tube w ith e ight w ire s in sulated w ith india-rubber. Mo st

o f the gutta-perchaw ires failed from the tw o she e ts o f gutta-percha


n o t be ing properly un ited ; but still some o f the w ires w ere in

w o rking o rder till the fo llow ing year, w he n athundersto rm came

acro ss the lin e and the lan d lin es w e re struck at adistan ce o f te n

or tw e lve miles from Co sham , and the w ire s w ere burst open .

The late Mr. Read had at that time aco n tract w ith the Company toke ep the se w ire s in o rder, and I w as at that time under his o rders.

Acco rdingly, tw o lengths o f gutta-percharod, about five -e ighths

diame ter, each rod co n tain ing thre e conductors and tw o se ts o f

pipes, w e re substituted fo r the se o ther w ire s, w hich w ere take n out.

This w as an actual submarin e cable , w orking in a circuit fromPo rtsmo uth to Whitehall , Lo n do n , and w as laid in “1848 o r the

begin n ing of 1849. It w as in 1848 I to ok charge o f this te legraph,and it w as laid shortly afte rw ards.

Thus,the n

, w e find the ideaof te legraphing under sea-w ate r

began at an early date in this cen tury, and w as perfe ctly realisedby the Ele ctric Te legraph Company as early as the latter part of1848 o r the begin n ing o f 1849. The mo st that can be claimed forthe w ire s w hich w ere laid do w n in Prussia— the gutta-pe rchacovered w ires— w as the in troductio n o f gutta-perchafo r un dergroun d n o t submarin e circuits ; and Mr. Co oke w e allkn o w ,

manyyears befo re

,had laid dow n subte rran ean w ire s sufficien tly in sulated

fo r w orking. I ought to men tio n w hen w e to ok up the se leade ntube s co n tain ing the thre e in dia-rubbe r w ire s from Co sham w e

fo un d that some malicious in dividualhad slit open the leade n tubeand partially damaged the in dia-rubber ; but, inasmuch, as he hadn o t quite cut through the in die-rubber, in sulatio n w as sufficie n tlype rfect to w o rk till the w ire s w ere de stroyed by lightn ing. Se e ingthat w e have greatly perfecte d the manufacture o f india-rubberco vered w ire s w e must n o t give gutta-perchathe e n tire credit,altho ugh it must have the large st share o f it in the constructio n of

allde ep-seacable s.

I have ‘

n o ticed an o ther remark in the paper, in w hich the

autho r do e s n o t en tire ly but almo st e n tire ly claim the in troductiono f tanks o f w ate r o n board ships fo r carrying the cable . That ise ssen tially an English inve n tio n o r in troductio n , and I take thisoppo rtun ity o f claiming fo r my coun try that mo st impo rtan t impro veme n t in the submerging o f te legraph cables, viz.

,that of


its spe ed,still these are n o t the co nditio n s of acable like the

Atlan tic passing in to the w ate r. That cable , as yo u kn o w ,is

cove red w ith ace rtain n umber o f ste e l w ire s covered w ith ‘hemp,

and coated w ith asubstan ce kn ow n as Clarke ’s Mixture . No w ,

the w ho le o f this presen ts asmo o th exte rior,but the m ome n t the

cable is passed ro und the drum it be comes flat in shape,and you

have an umber of fibre s sticking o ut of the cable .

W e find that the cable , instead of be ing smo o th, is n o w bristledallo ver w ith filamen ts. No w

,a cable go ing do w n ho rizo n tally

through the w ater experien ce s re tardatio n in propo rtio n to the

square of the ve lo city. Each o f these fibres is in apo sitio n pe rpe ndicular to the cable , so that w hile the greater part o f the cablew ill o bey o n e law — the results perhaps varying w ith the spe edeach o f the se hundred thousan d filamen ts obey the o ther law ; and

it is apity w e have n o t expe rimen taldatato prove ho w far on e

law predominate s o ve r the o ther.

During the paying-out of the 1865,1866, and 1869 Atlan tic

cable s, in o rder to allo w the n e ce ssaryamoun t ofslack to run out,and

to evade po ssible irregularitie s at the bo ttom,it w as n e ce ssary to

reduce the strain upo n the cable to o n e-third o r o n e -fourth thew e ight o f the length o f cable that w ould have hung had the lin ebe en perpen dicular to the bo ttom . There is, inde ed, n o difficultyin the me chan ical operatio n o f laying acable , pro vided it come s

o ut of the tank w ithout ge tting en tangled, or ge tting foul o f itsmachin e ry, and the amo un t of strain is so small that n o risk arise supo n that score , and n o tro uble n e ed be experien ced. But w he rethe difficulty is experien ced is w hen , o w ing to any cause

, yo u haveto haul back the cable . The cable has n o w to be lifte d sidew ays,again st the w ate r, and the resistan ce o f do ing that is so great that,in 1869, whe n pulling up acable from adepth of fathoms,mo re than tw ice the strain due to the w e ight of the cable had tobe applied, and then the cable did n o t come in so fast as halfam ilean hour. There is the difi culty, that you have n o t o n ly to lift itfrom the bo ttom, but to lift it broadside upw ards again st the w ate r

,

and, co n sequently, you are obliged, in de ep w ater, to lift the cablevery slow ly

,o r yo u are boun d to break it.

An o ther portion of the paper refers to asubject in w hich I am


perso nally in te rested ; that is, in the testing of faults. As early as1847

,in the Lon don stre e t w ire s

,I fo und it sho rte n ed the ope ra

tion o f remo vin g faults very much to be able to indicate by themeasureme n t o f the strengths of curren t w hat w as the le ngth o flin e un der test. The faults w e had w e re prin cipally caused by theso lder o f the jo in ts run n ing in and fo rming co n tact w ith o n e o r

more o f the copper w ire s, thus causing w hat is te chn ically calledme tallic con tact. It the n be came n e cessary to measure the

resistan ce betw e en the w ires and the leaden tube w hich w as the nused. That, I think, w as the first practical te st for faults, an d itw as adaily practice w ith me fo r mon ths ; still, there can be n o

que stio n that the first algebraical fo rmulae sho w ing how to ge t at

the po sitio n of afault w ere published by Dr. Sieme n s. The pape rcon tain ing this w as prin ted in March 1852, and afterw ards inGerman in Pogge ndorf

’s Annals. In that paper he gave ame tho d

w hich w as practicable , provided you had, as he required, tw o com

parable galvan ome ters— arather difficult thing to fin d in tho sedays. He has, how ever, it appears, sin ce modified this me tho dvery co n siderably. It w as about the year 1857 I published afo rmula

,unaw are of the on e for ge tting the po sitio n of faults in w ire s

by te sting from on e end ; an d at that time I thought this w as thefirst attempt to indicate the po sitio n o f afault by this mean s. It

w as,ho w ever, original in this re spect

,-that

,w hi le Dr. Sieme n s

required tw o o pe ration s, w ith comparable in strumen ts at each e nd,in my case o n ly on e operatio n w as required at on e end ; and thatmethod is, o n that accoun t, very o fte n very conven ie n t.In 1857 Me ssrs. Glass, Ellio t, and Co . made acable for the

Electric an d In te rnational Te legraph Company, w hich w as sub

merged betw een Englan d and Ho lland. During the submersio nof this cable afault appeared in No . 2 w ire . The vesse l w as

stopped : tests w ere made . I said, after some hesitatio n,the fault

must be o n board. Te sts be ing an e w thing then to Glass, Ellio t,and Cc .

,and the re be ing n o proper picking-up apparatus o n board,

it w as decide d to lay the cable and repair it afte rw ards. The cablew as acco rdingly laid, but be fo re w e reached the o the r side afaultappeared in No . 4 w ire , although o f asmaller character. The

method of te sting to w hich I have just referred an sw ered very w ell

76 SUBMARINE TELEGRAPHS. [9th Feb.

for obtain ing the po sitio n o f the fault in No . 2 w ire,w hich w as a

me tallic fault,o n e co nducting w ire be ing in co n tact w ith the o ther

w ire : this w as sho w n by the fact that there w as n o po larizatio nfrom this fault

,but allattempts to ge t at the distan ce o f the fault

in No . 4 w ire,afte r tw o days’ labo ur, e n tirely failed . We co uld

ge t n o n eare r to it than to w ithin adistan ce o fabo ut thirty m iles,because the re sistan ce of the fault w as co n stan tly varying. Whe nI came back to Lo ndo n I se t myse lf thinking o ve r this, and there sult w as the 10 01) te st. I w en t back, tried it, and w ith go o dre su lts

,for resistances w e re obtain ed w hich did n o t vary am ile .

The lo op te st, w hich is familiar to yo u all, I published in the year1858 .

In the fo llo w ing year a trial o f the value o f the lo op te st

to ok place be tw een Glass, Ellio t, and Cc .

, and Mr. Bosw e ll, w ho

w as in the service of Mr. Ne w all, it having tran spired that aman in the employ of Mr. New all had dr ive n anail in to the

cable fo r the pprpo se of destroying it. On coming to the faultin the No . 4 w ire I found that several attempts had be e n madeto injure the cable , altho ugh they had resulted in o n ly o n e minutefault.That is the first in stan ce I kn ow of e ndeavo uring to me e t and

succe ssfully me e ting the difficulty o f dealing w ith avariable fault.Dr. Sieme n s se ems to claim that fo r himse lf

,but inasmuch as this

w as published first in my pate n t o f 1858, and again in 1859, befo rethe Committe e o f the Privy Co un cil

,and again in 1860 befo re the

British Asso ciatio n,I take this oppo rtun ity of claiming fo r myse lf

bo th these tw o methods to w hich I have referred,and I be lieve I

am fully e n titled so to do .

I have still afe w mo re remarks to make , but, as the time fo rclo sing the me eting is already past

,I shall defer these un til o ur

n ext me e ting.

The discussio n w as then adjo urn ed .

NEW MEMBERS .

The fo llo w ing Candidate s w ere ballo tede le cte d

FOREIGN MEMBERS

H. A. M. ReederI. de JagerG. Blo cklin is

R . von EldikI . C. EversM. C . de Graaffe

MEMBERS

Wilhelm KieserAndrew T. Maginn ityH. Izaak WaltonWilliam LaddH. M. O

’Kelly

Assocm'rEs

Frank FisherGe orge W . FrodshamGe orge C. BompasWilliam Gurdo nJohn D. BarryS. ButcherJ. Phillips, R E.

The Me eting then adjo urn ed.

de clared

[23rd Feb.

The Fo rty-fo urth Ordinary Gen eral Me e ting w as he ld o n W edn e s

day , the 23rd February, 1876, Mr. C . V . WALKER,

Pre siden t,in the Chair.

The PRESIDENT said : At the last me e ting the paper read w as

by Dr. We rn e r Sieme n s, On the The o ry of Subme rging andTe sting Submarin e Te legraphs.

” Mr. Varley w as o n his legs w henthe time arrived fo r clo sing . I shallthe re fo re call upo n Mr. Varleyto con tin ue the remarks he has to offer ; but befo re do ing so I maybe allow ed to supply an om ission in amatte r o f date and histo ryw hich o ccurred in Mr. Varley

’s remarks. I am n o t surprised at

an item o r so e scaping n o tice w he n go ing in to date s, amo ng w hichI have myself be en floun dering for some time

,and have be e n

fe e ling the difficulty o fmaking them comple te and accurate . Withregard to the early histo ry of gutta-perchaw ire in this coun try

,

o n refe rring to the abridged list of pate n ts taken out from 1627 to

1857,published by the Comm issio n ers o f Pate n ts

, I find the first

thre e paten ts take n out fo r te legraph w ire s co vered w ith guttaperchaare the se , viz . in 1848, April 27th , by W . H. Barlo w an dThomas Fo rster ; the Barlo w part having refere n ce chiefly to in strumen ts, and the Fo rste r part to gutta-pe rchaco vered w ire . On the

fo llo w ing day, that is o n the 28th o f April, I sen t to Mr. Fo rste r

tw o m ile s of w ire to cove r w ith gutta-percha. His plan w as to

pass tw o strips o f gutta-perchabetw e en gro o ved ro llers heated bysteam ,

w ith e ight o r ten w ire s betw e en the strips ; and the tw o

bands o f gutta-perchaw ere thus pressed toge the raro un d the w ire s,

and the covered w ire s w ere n early, if n o t comple te ly,out apart by

the pro ce ss. The paten t referred to by Mr . Varley as the first

paten tMr. VARLEY : I beg your pardo n ; it w as Mr.Willoughby Smith

and n o t I w ho made tho se remarks.

The PRESIDENT : I beg Mr Varley’s pardo n . The second pate n t

for gutta-perchacovered w ire w as byMr. Lew is R icardo , and dated


September 4th, 1848 , and the third w as date d April 23rd,1850, by

Mr. Sieme ns. Tho se w ere , as far as I can asce rtain , the first

paten ts that w ere taken o ut in this coun try fo r co vering w ire s w ithgutta-percha.Mr. VARLEY, I be lieve o n the last o ccasion I omitted to

men tio n that the firstreal attemptatmakingand layingasubmarin ecable w as that of the Submarin e Te legraph Company, and I thin kthere can be n o doubt w hate ver that Mr. Jaco b Brett an d his co n

frem'es w e re the pe ople w ho first o f allhad the co urage to find

the mo n ey and had the bo ldn ess to make acable and lay itsuccessfully. In speakin g o f the prin te d co py o f this pape r Imen tio n ed in passin g the me thod of testing as being that o f Mr.

Latime r C lark. When the Atlan tic Cable failed in 1865 Sir W.

Thomson and I w e re e ngaged by the Te legraph Co nstructio n andMain te nan ce Company to advise them as to the be st means tobe ado pte d fo r te stin g the cable o f 1866 . We recommen ded th esystem in troduce d by Mr. Willoughby Smith fo r measuring cur

ren ts at the re ceiving e nd by in te rpo sin g great re sistan ce at thatend, w hich did n ot in terfere se nsibly w ith the in sulation o f the

cable but yet allo w ed the rece iving statio n to re ce ive from time totime signals from the ship . At that time w e prepared w hat hase ve r sin ce been called the pote n tial me thod, that w as the me tho dof measuring the po te n tial first at the junctio p be tw ee n the te stin gbattery and the re sistance ; secon dly, at the junctio n be tw ee n the

cable and the re sistance ; and lastly, at the differen t e nds. Thisme thod w ill be found in the archive s o f the Te legraph Co n structio n and Main te nan ce Company abo ut November o r De cember1865 .

Mr. Law es and Mr. Willoughby Smith recomme nded, insteado f the use of agalvan omete r, the use o f co nden sers

,w hich should

be applied to the se po in ts and simultan e o usly discharged thro ugh agalvanome ter, to measure this po te n tial. Sir William Thomsonw as in favo ur o f the e lectrome te r

,w hilst I w as in favour of the

galvan ometer ; but it w as, in e ffect, allthe same

un da' difl‘bren t co lours. On page s 17 to 20 in the prin ted pape rDr. Siemen s produces amethod w hich I can n o t se e very w ell,w inch is show n in figure 2 it co n sists of applying such abattery

80 SUBMERGING AND TESTING [23rd Feb .

at this end and such abattery at that e nd as shall produce equalpo ten tial at e ither termin us. No w

,if yo u had your cable in the

ro om,and your fault w as ame tallic arc, so that there w as n o vari

atio n o f the fault, yo u might apply that me tho d w ith succe ss. I

discussed that me tho d in 1869 w ith Mr. Charle s Hockin,and later

w ith Sir William Thomso n . I endeavo ured to put it in operatio no n the Fren ch Atlan tic cable in 1872, but o w ing to the con

tinn ed variatio n o f the earth-curre n ts it w as impo ssible to ge t anyreading that w as o f value . In fact

,allo rdinary me thods applie d

to that particular fault (w here the resistance w as fi'

om to

ohms) w ere use le ss fo r finding it out. They w ere,inde e d

,

such,that at o n e time they m ight give the fault at San Fran cisco ,

and at an o ther at St. Pete rsburg ; therefore , it w as n e ce ssary toadopt an o ther me tho d to ge t o ver that

, and this is the metho dw hich I adopted w ith comple te succe ss. I sen t o ut asignal to St.Pierre to charge his battery w ith saw dust mixed w ith oxide o f

zin c,and so lutio n o f zin c sulphate fo r the zinc ce lls

,and to take

care that n o copper go t in to tho se ce lls. The zinc plate s w ere

amalgamated every mo rn ing. The copper ce lls w ere charged w ithaso lutio n of n eutral sulphate o f copper. By this mean s yo u ge t abattery

,the differen t ce lls o f w hich w ill n o t vary much

,and

,this

be ing abattery of forty ce lls, they gave avery un iform result, so

that w e w ere able at each statio n to ge t asufficien tly accuratemeasure of po te n tial by mean s o f this batte ry and resistanceapparatus. [Illustrate s ]The result w as, that, although the fault varied, ye t w e de ter

min ed the po sition o f it w ithin thre e mile s,'

n o t by an y on e te st but

by amean of an umber o f te sts, fo r they varied very much e venw ith allprecautio n s. It w as the mo re importan t to de te rmin eaccurate ly the po sition o f this fault, because , had it be en thre e m ile sfurther off in stead of be ing in 230 fathoms o f w ater, it w ould havebe e n in Now ,

in this method, w ith con stan tly-shiftingearth-curren ts be tw e en the fault at on e end and the o ther

,it is

impo ssible ever to adjust the batteries o n e ither side so as to ge t

re liable readings. As I have said before , the first perso n to dealw ith variable earth-readings was myse lf ; but the subject w as o n ew hich o ccupied the attention of other person s,and,amongst o thers,

82 SUBMERGING AND TESTING [23rd Feb.

but there are more roads than o n e leading to Rome , as is pro vedby the succe ss o fMr. Varley

’s me thod.

Re garding the early histo ry o f gutta-perchaw hich w as discussedat the last me e ting o f the So cie ty I w ish to make afe w remarks.I may say I sto o d o n the thresho ld w hen gutta-pe rchaw as first

in tro duced in to this coun try. This w as I be lieve in the w in ter o f

1844-5, and n o t in 1843 as stated by Mr. Willoughby Smith ,

because I reco lle ct w e ll se e ing the first specime n o f gutta-perchaexhibited at the So cie ty o f Arts, I think by Mr. Mo n tgomerie .

At that time I w as yo ung and e n thusiastic, an d I begged Mr.

Mo n tgome rie to give me a piece o f this w o nderful stuff, the

co n templated applicatio n of w hich did n o t se em to go beyo n d thefo rmatio n o f w hips and similar article s. He w as kin d e n ough togive me a pie ce

,w hich I forw arded to my bro ther Dr. Wern e r

Sieme n s, w ho w as at that time an officer in the Prussian service,

and ajun io r member o f aCommissio n appo in ted to report upo nthe feasibility of te legraphs . He had the idea that the w iresshould be co vered w ith indie -rubber and laid unde r gro und

,and I

sen t him this pie ce of gutta-perchain order that he might tryw he the r it w as n o t superio r to india-rubber fo r in sulation purpo se s. He did so , and after some time , having procure d for himat his requ e st afurthe r supply, he made experimen ts

,and in the

co urse o f about tw e lve mo n ths he propo se d to the PrussianGovernme n t the use o f gutta-pe rchafo r in sulating the te legraphiclin e w ire . In the first place he tried to un ite tw o strips o f guttapercharo un d the w ire , and the lin e from Berlin to Gro ssbehre n

w as laid in 1846 in that w ay . It w as so o n fo un d,ho w eve r. that

the mo isture pen e trate d to the w ire s, and this led my bro the r tode sign amachin e w hich is still in existen ce and w as exhibited atVien na

,and w hich is very similar to thatused formaccaro n i making.

This machin e w as design ed in 1847, and in the early part of 1848some hundreds o f mile s and in 1849 some thousan ds o f mile s o f

w ire smade by mean s of it w e re laid in Germany. My bro ther didn o t at that time take o ut apate n t fo r his machin e because he wasin the Go vernme n t service , and as it had been do n e partly o n behalfo f the Go vernmen t it had become public to agreat exte n t : the pate n treferred to as having be e n take n o ut by him in 1850 w ill be fo un d

ism SUBMARINE rm GaAPns as

to embrace on ly some impro veme n ts in this machin e . Hen ce it isan un do ubted fact that gutta-perchawas applied to the insulationof w ire in Germany se veral years be fo re the pate n ts men tio n ed bythe Preside n t this evenin g as having be e n taken o ut in 1848. I

should corre ct myse lf. The pate n ts taken out in England in 1848

w e re fo r co vering the w ire be tw ee n strips o f gutta-pe rcha, amethod w hich had bee n tried by my bro ther in Ge rmany in 1846but the covering of gutta-perchaby means o f amachine w o rkingon the prin ciple o f alead pipin g o r maccaro n i machin e w as , I

think,n o t adopwd by the Gutta-percha Company un til 1850.

The refore , altho ugh submarin e telegraphy is decidedly an Englishe nte rprise it must be admitte d that much has also Me n efi

'

e cted

abroad to bring appliances to their prese n t state o f pe rfe ctio n .

An o the r remark I thin k fe ll from Mr. Varley w ith refe ren ce towater tanks o n board vesse ls

,and he implied that my bro the r

claimed the in tro ductio n o f those tan ks. If he refers to the paper,Mr. Varley w ill find that is n o t the case . He do e s n o t claim the

tanks, but says they w e re in troduced in England. But it so

happens I have hadagreat deal to do myse lf w ith the employme ntof these tan ks. Whe the r I w asabso lute ly the first to breach the ideaor n ot I w ill n o t say. It might have occurred te se ve ral, but may Isay this, that in 1859, w hen the Rango o n and Singapo re cable w as

w ried out for the Board o f Trade I w as employed to te st thatcable , and I strongly urged upo n the Governme n t the co nstructio nof water-tight tanks on board the steamship “British Que e n .

”

The matte r w as re ferred by Messrs. Glass and Elliott to the co n

structors o f the ship at Ne w castle , w ho w ro te a le tte r to the Board

tanks constructed o n board ship w o uld ine vitably fail o n acco un t o fthe natural motio n s o f the ship, and my re comme ndation w as

negatived . This was, pe rhaps, fo rtunate , because it gave rise to thefirstapplicatio n of the resistance the rmome te r fo r asce rtain in g thefact that acable is subject to spo n tan eo us ge n e ratio n o f heat w hencoiled in adry tank, and of pro ving the abso lute n ecessity o f

water tight tanks, w hich, as is w e ll-kn o w n , have be e n in use everW

I should like to make afe w remarks regarding an o bservatio nG 2

84 SUBMERGING AND TESTING (23rd Feb.

that o ccurs in the paper w here my name has be e n men tio n ed inco nn ection w ith ametho d o ffinding the depth o f w ate r be lo w the

ship in paying out acable,and as this is amatte r o f some in terest

I w illexplain more fully in w hat this metho d co nsists. It w as

used first, I may say, by myse lf in laying the first se ction the

sho re e nd) o f the Direct Un ited State s Cable , the o ther se ctio nhaving be en laid partly by my bro ther Mr. Carl Siemen s, andpartly by Mr. Lo efiler. We passe d acro ss co n side rable depths o f

w ater. The first cable laid w as laid upo n the so lid bo ttom o f the sea.

The secon d cable w as laid very much to the so uth o f the first,so

as to leave sufi cien t distan ce be tw e e n the tw o cable s. We did n o tkn o w the depth of w ater be tw e en the shore and the extreme e nd

o f this headlan d (illustrating o n the board) ; and as the cable w as a

heavy on e it w as impo rtan t to kn o w the depth. Mo st of you

kn o w that in paying outacable from adrum there is really n o dire ctindicatio n of the depth of seabelo w the ship . The strain w hich isapplied is mean t to be such as to balan ce the w e ight o f the cablefrom the ship do w n to the bo ttom o f the sea; but if the depth is n o tkn ow n it is difficult to say w hat the re tarding fo rce should be . By

applying to o much yo u ge t atight cable ; w ith to o little , much cableis lo st in depths w hich are con siderable . The mo tio n of the shipthrough the w ater is n o t asufficie n t crite rion , be cause you may bemo ving w ith the w ater at aco n siderable rate . But there is, n eve rthele ss, amethod w hich the practicalcable -layer may re sort to fo r

finding o ut w he ther he is paying out the prope r amo un t o f slack o r

n o t, and by the same mean s ascertain the depth o f w ater be lo w .

Assume that the cable run s o ut over the drum , w ithadynamome terattached to it, at the rate o f five kn o ts an ho ur, and the strain iso n e to n . This may be apro pe r amount o f cable to be paid o ut

upon the ground ; but it may be the ship is go ing o n ly thre e kn o tsan hour o ver the ground in stead of five . To ascertain w he ther itis so o r n o t— the strain be ing tw en ty cw t. o n the dynamome terin crease the strain by an o ther cw t., and then carefully n o te the

numbe r o f revo lution s of the w hee l pe r minute . If the increase o f

o n e cw t. has n o efi'

ect upo n the number of re vo lution s o f the payingo ut drum,

the n it is pre tty sure that unn e ce ssary slack is n o t be ingpaid o ut ; but if the in crease of o n e cw t. on the dynamometer

1m .) SUBMARINE TELEGRAPHS . 85

cause s the numbe r o f revo lutio n s to fall se n sibly— say from fifte e n

or sixte en re vo lutio n s pe r min ute to fo urte e n— the n to o much slackis be ing paid o ut, and the w e ight sho uld be increased. If the caseis do ubtful I w ould put on aconsiderable amoun t, say three o r four

cw t. This w o uld (if agreat deal o f slack is be ing paid out) sto pthe break-w he el, and the ship w ill pass o ver the ground w itho ut

The PRESIDENT : In co n tinuation o f this discussio n w e have acommun ication from Mr. Sabin e

,w ith some extracts from the

corre spo nden ce o f the late Sir CharlesWheatsto n e,having re fere n ce

to his early vie w s and his expe rime n ts w ith submarin e cables ; bu tit is po ssible

,as w e have be e n talking of the early histo ry o f gutta

perchaw ires, that Mr. Fo rste r,w ho is prese n t this even ing

,might

fee l disposed to say afew w ordsas to his early expe rien ce o f the

Mr. Foas'rEB : I did n o t expe ct to be called upo n to speak, butI cml te ll yo u the o riginal mode ado pted , and w hy it did n o t

succe ed efl'

ectively . The plan o f carrying the thing o ut w as to

cleanse the go tta-percha, w hich w as don e first by putting itthro ugh aco lan der and w ashing and masticating it be tw e e n tw oho t ro llers, then putting it betw ee n tw o pairs o f rolle rs o n e abo vethe o the r, w ith guides at the sides

,so that the gutta-perchaw as put

into the to p pair and in to the lo w e r, and bo th , acte d upo n by thesame mo tio n

,bro ught out astrip each abo ut fo ur inche s w ide .

These w e re taken to apair of flute d rollers made to carry tw e lvew ires thro ugh the flute s, o ne strip be ing placed o ver and the o ther

under the w ire ; the band o f gutta-pe rchaand w ire came o ut at

the o ther e ndas acomple te be lt, and the edge s of the flutes n earlyout thro ugh. But you are aware that go tta-pe rchais charged w ithalarge amo un t o f w oody substan ce s, and it is difficult to get rid o f

them thoroughly ; and the re sult w as in the first instan ce n umerousfaults in the w ire s w hen they w e re teswd. Afte r the diflicultie s

in co n n e ctio n w ith that w ere overcome , w ires w ere laid and used.

I be lieve the w ho le o f the w ires through the tun n e ls o n the So uthEastern Railway w e re so laid, and it was fo und to be o f greatadvm tage . But very sho rtly afte r that agreat improveme n t w as

made by the Go tta-pe rchaCompany, I think unde r the auspice s o f


Mr . Beverley, and I am o f opin io n that it w as called his pate n t atthe time . That had this advan tage o ve r my plan . It w as acylinde rw ith asmall box at the side

,the o n e in fact n e w used. The cylin der

w as kept ho t by asteam jacke t, the gutta-perchaw as put in to it, apiston w as driven do w n , and at the extreme e nd w as asmall boxw ith atro ugh of w ate r

,and athin coating of gutta-pe rchaw as put

upo n the w ire s each time o f passing thro ugh the cylinder. The

w ire s had seve ral coatings o f gutta-perchaput o n them ,so that the

faults of o n e coating w e re remedied by that w hich w as put o n afterw ards ; an d this made avery perfe ct article , bo th for use and in

appearance . Prio r to that the Chairman o f the Electric Te legraphCompany, w ho w as o f course acquain ted w ith the plan I adopted,pate n ted amo de o f ke eping the w ire s in o n e ban d o f go tta-perchain stead o f separate ly. But it w as fo un d that the un io n o f the tw o

strips of gutta-perchaw as n o t so perfect as w as an ticipated, andco n sequen tly the plan did n o t an sw er w e ll for te legraphic purpo se s.

The SECRETARY then read the fo llow ing commun ication fromMr. Ro bert Sabin e

25 , Cumberland Terrace , Regen t’s Park, N.W .

15th February, 1876.

To the S ecretary of the Socie ty of Telegraph Engin eers.

DEAR SIR,— As the Members o fthe So cie ty o fTe legraph Engin e e rs

have at the mome n t under discussio n the subje ct o f Submarin eTe legraphy, it has be en sugge sted to me that itmight be in tere stingto them ,

from ahisto rical po in t of view,to in spe ct the draw ings

made to illustrate the earlie st plan o n re co rd— that sugge ste d by thelate Pro fe sso r Wheatsto ne— for the e stablishmen t o f asubmarin ete legraph be tw e en Fran ce and England.

I have therefore se n t yo u the se draw ings, and I shall be muchobliged if you w ill kindly have them placed upon the table for thein spection of the Members at the n ext me eting.

From the perusal of old lette rs w hich have re cen tly come in tomy po sse ssio n , I find that asubmarin e e le ctric te legraph w as, as

early as 1837 , a theme upo n w hich Pro fe ssor Wheatsto n e w as

greatly in tere sted, and upo n the pre liminary de tails of w hich heappears to have spe n t ago od dealof time .


The earlie st prin te d men tion of this scheme is to be fo und in thefifth Railw ay Re po rt o f the Sede ct Committe e o f the Ho use o f

Commo ns. When ‘

under examinatio n be fo re this Committe e , o n

as to his o pin ion o f the practicability o f establishing an electri ccommun ication by means ofacable be tw e e n Do ver and Calais.On mfe re nce te Lc' FanaAa Brusse ls paper o f the 30th

September,1840, you w i ll find it stated that : “M. Wheatsto n e

pen se qu ’il e st po ssible de commun ique r avec so n appare ile n tre

Douvre s ct Calais ; ilrepete e n'

ce momen t ses expérien ees h

l’Observato ire de Bruxelles, e n prew nce de plusieurs savans

And in the Bulletin dc l’Academie R oyals de B ruxelles, fe r

(hxtobe r 7th, 1840, yo u w ill find an o tice o f Profe ssor Wheatstone

’s n e w te legraph in strume n ts, w ritten by Profe ssor Que te le t,

in w hich it is cw te d : “On serasans doute charmé d’appre ndre

que l’auto ur atro uvé le meyen de transmettre les signaux e n trc

l’

Anglete rre et la°Be lgique , malgré l’

obstaele de lame r. So n

voyage so rattachait e n partie h cette importante operatio n , qui

me ttrait I’Angle te rre e n rappo rt immediat avec n o tre pays, lafi ance , laHollands , l

’

Allemagn e , e t méme laRussia.

”

Afte r makin g his expe rime n ts in the Observato ry at Brusse ls,Professor Wheatston e appears to have re turne d to England and tohave o ccupie d himse lf dilige n tly w ith the preparatio n o f the tw o

defi iled plan s w hich I have the pleasure of se nding you . I find

from an ote in his han dw riting that they w ere complete d inOcto ber 1840

,and w ere exhibiwd to agreat numbe r of visito rs at

King’

s Co llege .

SHEET I.’

show s the metho d of in sulating and making the cable ,and ho w it is to be put o n board the laying

-ship . It co n tain s :

(1) A section , e nd-vie w , and plan of the apparatus forw rapping the co pper co nducto r w ith its in sulating co rd

tane o usly cove ring se ven such w ires to fo rm acable

(3) A se ctio n and plan o f amachine for bin din g the se ve n

co vered w ires w ith sn outer se rving e f cord so as to e om


(4) Alo ng the bo ttom o f the draw ing how the cable , in itsvarious stages, is to be passe d through baths o f in sulatingmate rial, and how it finally reache s t he ship .

SHEET II . show s the propo sed route of this cable , and the

me thods o f laying,jo in ing

,and unde r-run n ing. It co n tain s

(1) A se ctio n and chart o f the chan n e l be tw e en the So uthFo re land and Cape Grisn ez

(2) The cable-barge be ing tow ed by asteamer and payingo ut the cable ;

(3) A se ction and plan of the stem e nd of the cable-barge ,show ing thre e o f the drums o n w hich the cable w as to besen t to sea

(4) The method of co nn ecting the end of the cable from o n e

drum to that o n an o ther ;(5) The steame r under-runn ing to findafault ; an d finally,(6) A se ction and perspective of a piece of the propo se dcable .

These draw ings w e re exe cuted fo r Professor Wheatsto n e by aPo lish draughtsman

,named Luto w ski, w ho w as at the time in his

employ.

I find aMS. article in his han dw riting, en titled, On amean s

of e stablishing an Electric Te legraph be tw e en the coasts o f Englan dand Fran ce

,

”in w hich o ccurs the fo llow ing passage : Each w ire

sho uld fo rm the co re o farope lin e w e ll saturated w ith bo iled tar ,and allthe lin e s he made in to a rope prepared in the same

man n er. This gives an ideaof the kind of in sulatio n con templated ia1840.

In the year fo llow ing Profe ssorWheatsto n e appears tohave go n e w ith his scheme and the se draw ings to Paris. Duringhis stay there

,he says, in aMS. n o te , that he let Mr. J. Jo seph

Silbe rman n take tracings of the draw ings.1'

P ro fe sso r Wheatsto n e do e s n o t appear to have confin ed his cablescheme to jo in ing Fran ce an d Englan d ; fo r to w ards the e nd o f

Captain White’s chart of the English Chann e l, given me by Captain B eaufo rt.

— MS . n o te .

1“These tracings I find, from aletter, dated 22 July, 1855 , from Mr. Silberman n

(Co llege de Fran ce ), w ere len t by him subsequen tly to M . Pouillet, w ho depo sitedthem in the Co nservato ire desArts etMetiers."

so so nm omc AND rasrmo [earsm .

incurred by assisting me in the so lutio n o f any of the fo llo w ingque stio n s

“1 . Will the curre n t at an y part o f the passage across the

Chan n e l have any e ffe ct in displacing arod o r tube o f lead , be ingin diame te r from aquarte r to halfan in ch

2 . What w o uld be the efi'

ect o f agroundM o n such arodo r tube ?

“3. What is the depth o f the sand abo ve the chalk in variousparts o f the passage ?

“4. Ho w much time w ould e lapse before' the rod or tube

w ould be com e imbe dded in the sand ?“5 . Is any danger to the tube to be apprehe nded from the

ancho rin g o f ve sse ls, the dredging o f fisherme n , o r the rakin g o fsmuggle rs ; and, if so , ho w is such dange r to be avo ided ?

“6 . What is the e ffe ct o f the lo ng-co n tinued actio n o f sea-w ate r

upo n lead ?“7. Is there any lighthouse o n the coast of England, o r an

island, or ro ck,w ithin amile from the land, w here ate legraphic

commun ication to the shore w o uld be useful ? Or is the re anyguard-ship for w hich it w ould be an object to transmit in stantane ous in te lligen ce to the sho re ?

I remain &c.

,

C. Wnaa'rs'ro n s .

The allusio n to lead tube in some of these questio n s explains themean ing o falo ng bill w hich I find, date d be tw e e n De cembe r 1845and May 1846, from Mr. W . H. Darke r

,o f 9

,Paradise Stre e t,

Lambe th, fo r making experimen ts “to en clo se aco ppe r w ireinsu lated w ith w o rste d and marin e glue in alead pipe .

”And o n

1 1th August, 1846, abill from Mr. H Mapple fo r “making n in etho usan d feet o f tube-pro tecte d w ire e nume ratin g the mate rialsas “lead , co ppe r w ire , marin e glue , and co tto n .

”

Be tw ee n Jun e and August 1846, I find le tte rs from Mr. W. H.

Hatche r, Engin e e r to the Electric Te legraph Company, w ith re gardto apropo sed lin e o f te legraph in lead tube fo r cro ssin g the harbo urat Po rtsmo uth , fo r w hich the abo ve w as probably in te nded .

It may be in teresting to the members o f the So cie ty to kn o w


that as early as 1845 Pro fe sso r Wheatsto n e co n templated employing gutta-pe rchain the co n structio n o f his pro po se d cable s ; buth o w he pro po sed to apply it is n o t clear. In 1845 I find him in

correspondence o n the subject w ith aMr . Edw ard So lly o fBedfo rdRo w ,

w ho promises to pro cure some fo r him ; and o n Octo be r 18tho f that year I find ale tter fro maMr . J. S . Lister

hlamen ting

“thatth ere is n o gutta-pcrchain the marke t

,that the last parce l w as

purchased by Mr. Hanco ck o f Charing Cro ss, and that its valueis abo ut Is. per lh.

, that the supplie s expe cte d for the n ext tw o

years have be e n bo ught up by some party w ho has apate n t fo r theuse o f it in an atmo sphe ric Railw ay.

So far as I have had time to e xamin e Pro fe sso r Wheatsto n e ’

s

old pape rs,I have n o t fo und much e lse than the abo ve w hich

bears histo rically upo n the subje ct, but my search is n o t ye t

The practical and engin ee ring details w hich are embodied inthese plan s and suggestio n s appear o f co urse to be ve ry crude

,and

the e lectri calpart to be very insufficie n t w he n judge d by themeasure o f o ur pre se n t kn o w ledge ; but it is n ecessary to rememberthat this pio n eering w o rk w asallin pro cess of creatio n years befo resuch athin g as areal submarin e cable w as se riously attempte d

,

and the author of them had n o experien ce o f any analogous o peratio n to guide him. View ed in this light, I fee l sure that theMembe rs w ill regard these tw o draw ings as mo st in te re sting re licsin the earlie st histo ry o f submarin e te legraphy, and that the le ngthofthis le tte r will be pardo n ed in co n seque nce .

I am , dear Sir,Yours very truly,

Ro sna'r Su ms.

Norm— The tw o accompanying illustratio ns have be e n do n efrom n egatives take n directly from fac-simile s o f the o riginaldraw in gs by the pho to -lithographic proce ss. The dime n sio n s o f theo riginal shee ts are 28" x


Mr. F. C. WEBB : This discussio n hitherto has fo rmed an histo ricalabstract o f the deve lopmen t o f submarin e te legraphy, and Ihave n o doubt there are many ge n tlemen presen t w ho w e llre co lle ctmany po in ts w hich have o ccurre d during the last tw en ty-five years,and I think it is our duty to place o n reco rd such facts as w e maybe in po ssessio n of, and w hich w e may think o f impo rtan ce in anhisto rical po in t o f view .

With regard to the early days o f practical submarin e cable s, Irecollect and was presen tat the laying from the Go liath o f the

first Dover and Cape Grisn ez unpro te cted gutta-pe rchain sulate dw ire , w hich may be regarded rather as an experime n t. Subecquen tly the Blazer payed o ut the existing fo ur-w ire Do ver andCalais cable , w hich has lasted tw en ty-five years. That w as also anexperimen t, to agreat exten t, in the paying out w o rk , fo r hardlyany machin ery w as employed in the operatio n , and the first cable s,I think, w hich w ere laid by anything like me chan icalmeans w ere

the Ho lyhead and How th and the Do ver and Oste n d lin es, laid byMessrs. Ne w all. I w as n o t presen t on tho se o ccasio n s

,but afte r

w ards examin ed the machin ery by w hich they w ere laid. I be lie vethat w as the first time the drum-break w as used . No w w e havethe Appold break added, instead o f the ordinary strap and leve r

,

but the drum n o w used is the same as that w hich w as in troduced byMe ssrs. New all in 1853. Of course if it had be en me re ly the factthat Mr. New all had use d the drum-break fo r the first time in tho seearly days, and afte rw ards there w ere improveme n ts o n it

, therew o uld be n o such very great credit in it, because n obody e lse hadachan ce of trying his talen ts in the laying of cable s,

’

but w he n w e

come to the Atlantic cable o f 1857 an o ther kind o f break w as

adopted, w hich w as like that sho w n in fig. 1,and w as used as a

suppo sed improvemen t o n that o f New all.In the next year there was aSe lect Committe e appo in ted, and


straps, w ith five turn s ro un d each drum . (Figs. 4 and It must

have be e n avery po w erfulbreak and just the thing fo r laying suchacable . But the n ext year Mr. Bre tt did n o t take Mr. Thompso nw ith him ,

and the same machin ery fo r asix-w ire cable abso lute lyfailed afte r tw o starts from the lan d and abo ut e ighty mile s o f cablew ere bro ught back w hilst sixty mile s o f cable w ere picked up byMr. Lidde ll and myse lf in the Elba, and that w as the first heavycable picked up from de ep w ate r. On ase co nd o ccasio n acable w hichreached w ithin asho rt distan ce o f the Island o f Galitaw as lo st, asthey had n o buoys : apo rtio n o f it w as re covere d by the expe ditio nthat picked up the sixtymile s of heavy cable . In the case o fthe Bo na

Cagliari cable alluded to in the pape r it is men tio n ed that w ate r

tight tanks w e re used. That is n o t correct. They w ere iro n tan ksbut n e ve r in te nded to be w ate r-tight at that time , and I think Mr .

C .W . Sieme ns is right in taking credit fo r be ing the first to recom

mend tho adoptio n o f the w ater-tight tanks. The tanks use d in1857 fo r the Bo nalin e w ere iro n tanks but n o t in te n ded to ho ldw ater. That cable can n o t be said to be an abso lute succe ss

,altho ugh

n o do ubt it w as the first cable that w as even tually carried fromlan d to lan d, but it ran sho rt thirty mile s from Chis w ere it w as to

be laid, and my first w o rk w ith Mr. Ne w all w as to go out and pickup the e nd and comple te the cable for the distan ce of thirty mile s .

W e w e n t o ut in the Blaze r tug from Marse ille s ; w e had n o

picking-up gear, n o t eve n abo w sheave,an d I rigge d upatempo rary

bo w sheave . Whe n the cable ran sho rt they had spliced o n te n

mile s o f single w ire cable and had run this w ithin ten mile s o f CapeSpartave n to . This w e grappled fo r and the n picked up by handtill w e came to the splice . There is o n e po in t w ith regard to that

cable w hich de serve s histo rical n o tice . It w as the first cable o n

w hich adynamome te r was used,and I think Dr. Wern e r Siemen s

SUBMAR INE TELEGRAPHS 95

can claim that he w as the first pe rso n to recomme nd, w hilst Mr.

Ne wall was the first to ado pt, the dynamome te r. It was averyrough kin d of dynamome ter, but answ ered the purpose . It is sho w nin fig. 6. I m n o t myse lf e ngage d in the laying o f the Bo ne

cable acro ss the dee p w ate r but o n ly at the comple tio n o f it, as I

have men tio n ed. I w as afte rwards o n the Maltaand Co rfu cablein the same ship

,the Elba

,and that w as the first time I saw and

used thedynamome te r that I have de scribe d. This fo rm o f dynamometer w as improved. I speak o n ly from hearsay

,but I be lieve

in the case o f the first Re d Seacable Mr. Ne walladopte d thisplan (fig. I am so rry Mr. Fle eming Je nkin is n o t he re

,as

he was o n board at the time o f the w o rking o f this machine . It

Fig. 7.

wasakind o f self-acting break and dynamometer combined. The

dynamome te r mo st gen e rally use d at prese n t w as first employed inthe 1858 Atlan tic.

The que stie n w hich Dr.Wern e r Siemens asks in his paper, as tow he ther the fo rmulao f Messrs. Lo ngridge and Bro o ks is co rrect

or n ot, I am n o table to answ er, as I do n o t feelmyself compe te n tto e n ter in to the mathematical analysis ; but I think if the re w as

pancy before n o w ,be cause many cables have be en laid acro ss the

Atlan tic and w e have n ever heard anything w hich disagre e s w iththe results po in ted o ut by Lo ngridge and Bro oks . It is true veryfe w person s may have go n e in to the calculation to pro ve ho w the

actual strain upo n acable co rrespo n ds w ith that give n by theflormula

,fo r e ve n to do this w e should require to kn o w the co e ffi

cie nt o f the longitudinal frictio n ,and this is n o t often tried. Therefe re ho w w e are to te st the co rrectn e ss o f that calculatio n I do n o t

kn o w , because no body takes the tro uble to go in to it, and w he the rthe lo ngitudinal co eflicie n t is as the square o r directly as the ve lo


city the re se ems to be n o mean s o f ascertain ing. Cable s are laidw ithout these calculatio n s be ing made , and there appears to be n o

mean s of sho w ing ho w far they are co rrect in am inute po in t ; buttake n gen erally w e kn o w that they agre e as regards the re latio n o f

spe ed, strain,&c. ,

w ith practice . But there are po in ts in Mr.

Lo ngridge’s paper w hich any e ngin e e r w ho has to lay cable s

w ou ld do w e ll to think o f, and the re are some po in ts w hich I

be lieve invo lve ve ry serio us co n side ratio n s. There is o n e po in t inparticular. He show s that if the ship w hich is paying o ut the

cable , w hich de sce nds in astraight lin e , in clin ed to the ho rizo n , issto pped sudde n ly and remain s statio nary

,the cable w ill assume a

catenary (fig. and if the cable has be en paid o ut w itho ut slackagreat strain w ill come o n it.

Suf fi ce if Set

In paying out the old Atlan tic cable at the rate of 6 fe e t per

se co nd the strain w ould be abo ut 148 cw t.,w he reas the cable itse lf

w ould o n ly stan d about 85 cw t . Of co urse in practice the shipw o uld be put aste rn so as to preven t this strain . But the re isan o ther case w here this pro blem come s in to play w hich is far mo re

se rious. Suppo sing w e have to deal w ith gro un d at the bo ttom o f

the sealike that sho w n in fig. 9 (and this is amatte r po in ted o ut

by the Fre n ch w rite rs, but n e ve r by English) ,as the cable sinks inastraight lin e very slightly in clin ed to the ho rizo n , in paying o ut

w he n the cable sudde n ly touche s the high po in t here (p o in ting to A),it w ill so o n be mo o red by the cable that sinks to the gro un d o n theship’s side of the po in t A,

and if this o ccurs befo re the po rtio nA B has had time to sink and drag sufficien t slack back o ver thepo in t A,

so as to allow it to take up acate nary o f small strain , thecable may be left w ith aflat cate nary, giving co n siderable strain o n

the cable , and n o do ubt that w ould be the case w here the cable iseve n laid w ith some slack but laid w ith to o small aper-cen tage o f

slack, and this may be the cause of some o f the failures. Fo r

98 SUBMERGING AND TESTING [23rd Feb,

The follow ing Can didate s w ere ballo ted declarede le cted

FOREIGN MEMBERS

H. Baro n .

J. Duco te.

A. B equet.J. Raymo nd .

B .Meyer.

MEMBER

Ge orge Sticklan d Crisw ick.

ASSOCIATES

Jo seph H. Smith.

Jame s Sto tt.Ern e st Edw ards.

S. Sudw orth .

J. M. O’Haire .

Lie ut. H. S. Watkin , R A.

0 . E. Alle n .

Henry Carlisle .

Benjamin Duff.Co smo Go rdo n Ho w ard.

Majo r W . H. Co llin s,R E.

STUDENTThe odore Walro nd.

The Me eting then adjourn ed.


The Fo rty-fifth Ordinary Ge n eral Mee ting w as he ld on Wodacaday, the 8th March

,1876, Mr. C . V . WALKER

,

The PREBIDENT : Be fore pro ceeding w ith the regular busin e ss ofthe e ven ing, I regret to have to in fo rm yo u that w e have receivedfrom Mr. Scudamo re ale tte r co n tain in g his resignatio n o f mem

bership. Mr. Scudamo re , as yo u kn o w ,having left the co un try

,

and having retire d from the Po stal Te legraph se rvice , tho ught ittime to re tire also from the So cie ty . At the same time it affo rdsme pleasure to have to an n o un ce to yo u the fo llo w in g re so lutio nThe Co un cil o f the Society o f Te legraph Engin ee rs

,reco gn ising

the valuable services re ndered to telegraphic scien ce in thisco un try by Mr. Frank Ives Scudamore , C.B.

,and past-Presiden t

of this So cie ty, accept, w ith great regre t, his resignation ofmem

he rship, and, in o rde r to show the high appreciatio n by theSo ciety o f these his se rvices, have appo in te d him from this datean Hon o rary Member o f the So cie ty.

”The Acting-Se cre tary has

be en instructed to communicate the re so lution w hich you have so

The PRESIDENT : A commun icatio n has bee n re ce ived fromMr. Willo ughby Smith, o n the Variatio n of the Re sistan ce o f

Silen ium ,w hich the Acting Se cre tary w illread be fo re w e re sume

th e discussio n o n Dr. Wern er Sieme ns’

s pape r.

The commun ication w as read acco rdingly, and w ill be foun damon g the Original Communicatio ns at page 183.

The PRESIDENT ; We w ill n ow ,if yo u please , resume the dis

en saiou w hich was adjo urn ed from the last me e ting ; but previo usto do ing so the Acting-Se cre tary w ill read acommun icatio n w hichhas be en re ce ived from Dr.We rn er Sieme ns in re ply to the remarksmade upo n his paper at o ur tw o last mee tings. W e shall th e nbe happy to hear the furthe r remarks w hich any o n e pre sen t mayhave to make . It se ems to me that w e have go n e alittle back.

H 2

100 SUBMERGING AND TESTING [8th March ,

and o ut of the scope of the subje ct, to o much in to the early histo ryo f it ; but the re w ere tw o o r thre e po in ts in Dr. Sieme n s’s pape rw hich w ere w o rthy o f compariso n w ith o ur pre sen t kn o w ledge o n

the subje ct. At the same time I think w e have n o w almo st e x

han sted its past histo ry, and may , probably, have go n e a littlefurthe r in to it than w e in tended ; but that may have arise n fromthe que stio n s starte d by the first tw o lin e s o f Dr. Sieme n s’s pape r.

The Acting-Se cre tary the n read the fo llo w ing commun icatio nfrom Dr.Wern e r Sieme n s

B erlin , 25th February, 1876 .

If Pro fe sso r Faraday, as Mr. Willoughby Smith stated, did n o t

call public atte n tio n to the e le ctrical qualitie s o f gutta-pe rchaun til1848

,that ce rtain ly w o uld prove the prio rity o f o ur unde rgroun d

w ire s in sulated w ith gutta-pe rchaw hich w e re laid in the year 1847be tw e e n B e rlin and Gro ssbe re n . In my pape r, ho w eve r, I hadn o t in te nded to claim the first in tro ductio n o f gutta-perchaas anin sulating mate rial ; w hat I claimed w as the co n structio n o f the

first machin e fo r man ufacturing gutta-pe rcha cove red seamless

w ire s. Sho uld anyo n e claim aright to prio rity in the co n structio no r use o f such gutta-perchacovering machin e s

, I should ask fo rstateme n ts indicating w he re and w he n such inve n tio n w as pub

lished,because in que stio n s o f prio rity the first publicatio n o n ly is

decisive . Whe ther gutta-pe rchabo ttle s had be e n made be fo re myinven tio n

,as w as also stated in the discussio n

,is quite indiffere n t

to the que stio n o f gutta-perchasubmarin e w ire s.Ne w all succe eded in laying aheavy de ep-sea cable o n ly by

mean s o f my the o rie s o f submerging cable s,and by employin g

co rre spo nding paying-ou t gear. Even if Mr. Bre tt had employe dasteame r in stead o f a sailing ve sse l he w ould n o t have be en suc

ce ssfulun le ss he had employed avery po w e rful steamer w ith sufficie n t break-po w er upo n the cable . New all succe ede d o n ly afte rfo llo w ing my advice , w hich w as to tow his sailing ve sse l by anItalian steam frigate , and to co n siderably in crease the po w e r o f thebreaks

,co o ling them w ith astream o f co ld w ate r. The fo rce s

bro ught in to play in laying de ep-seacable s w ere n o t sufficie n tlyrecogn ised at that time .


fo und out that method indepe nde n tly of o thers ; and he also w as

the first w ho published it in accessible jo urnals. That very me thod ,ho w ever, w as already ge n erally adopte d in the years 1848 to

1853 by us fo r the de terminatio n o f faults in in sulate d gutta-pe rchaw ire co ils

,as w e ll as in do uble lin e s.

My fo rmulae fo r the de te rminatio n o f faults in single w ire s alsoin clude the po ssibility o f finding the po sitio n o f afault by te stingfrom o n e e nd o n ly

,the o ther e nd of the w ire be ing in sulate d during

o n e measureme n t, and to earth during ase co nd measurement.

Mr. W . H . PREECE : I read Dr. We rn er Siemen s’

s pape r

w ith great in tere st, and I have follo w ed the discussio n w ith

equal in tere st. There is o n e po in t co n n ected w ith the paperw hich struck me more than any o ther, and that is the very littleregard that Dr. Wern e r Siemen s has paid to his o w n perso nalin tere st

,and to his o w n perso nal effo rts, in furthering the advan ce

me n t o f submarin e te legraphy. It is amisfortun e , perhaps, thatthe discussio n has

,I might say, dege n erated in to que stio n s o f

priority rather than in to the examinatio n o f the prin ciple s broughtfo rw ard in the paper ; but that is w hat every n ew thing is mo re

o r less liable to , and submarin e te legraphy is as ye t but alittlechild. There are tho se in this ro om and living in Englan d w hohave played apart in rearing this child

, and w ho are naturallyanxious w he n an oppo rtun ity o ccurs to blo w the ir o w n trumpe t. I

must say, ho w eve r, thatDr. Wern er Sieme n s, w ho has had agran do ppo rtun ity fo r blo w ing his trumpe t, has n o t taken advan tage o f

it. There are ve ry few perso n s w ho have do n e mo re to furthe rte legraphy in every bran ch than Dr. Wern er Sieme n s and his

distingu ished bro thers. This paper is avaluable acquisitio n to

the lite rature of te legraphy. It place s the the ory of the layin gof submarin e cable s o n avery plain and simple basis, and bringsthe various facts together in away that can be easily comprehendedby all.We ought to draw adistin ction betw e en those w ho have exercised

the ir ingenuity in sugge sting pre tty and n o ve l ideas,and tho se w ho

have actuallyassisted in driving the coach, that is to say, in re nder

ing these ideas practical. Those w ho have pushed ahead the infan t


child— te legraphy— undoubte dly dese rve that w hat they have do neshould be placed upon the re co rds o f this So cie ty. The re is o n ein dividual w ho has made agreat many te legraphic experiments,but be cause there was no te legraphic so cie ty m those days to reportthem they have almost dro pped o ut of n o tice . In the Pro ce edin gso f the Asiatic So cie ty fo r Septe mber 1839 there is re corded ase ries of careful experimen ts made by Dr. O

’

Shaughn e ssy (n o w

Sir William Bro oke ), o n amean s o f cro ssin g riversand carryingou t submarin e te legraphs, w hich w ere made early in that year, andthe way in w hich these expe rimen ts w e re co nducted is so in

te re sting that w ith your pe rmission I w ill read ashort extract toyo u .

He says,“In sulatio n

,acco rding to my expe rime nts, is be st

acco mplished by inclo sing the w ire (previo usly pitched) in asplitratan and the n paying the ratan ro un d w ith tarred yarn

,o r the

w ire may, as in some expe rime n ts made by Co lo n e l Pasley atChatham ,

be surro un ded by strands o f tarred ro pe and this bypitche d yarn . An in sulate d ro pe o f this kin d may be spread alo ngaw e t fie ld, nay, even led through ariver, and w ill still co nductw itho ut any appreciable lo ss the e lectrical signals abo ve described .

”

At o ur last me e ting w e saw Sir Charle s Wheatsto n e ’

s in te restingdraw ings o f 1840, and heard ade scription o f the cable that he pro

po sed to lay be tw ee n Englan d and Be lgium ,but inasmuch as that

suggestio n w as n ot brought to light till afte r acable w as actuallylaid it w as n ot o n e of tho se steps w hich actuallyassiste d in the pro

gross o f telegraphy. The first practical andactual experime n tmade

acro ss any w ate r in Europe w as un do ubtedly made by o ur w o rthyPre siden t,Mr. C. V .Walker, in 1849. In 1850 the first actual_subm in e cable w as laid be tw e e n England and France through theexertion s ofMr. Bre tt. The follow ing year an o ther cable w as laidbetw een Dove r and Calais through the exertio ns o f o n e w ho se nameis n o t much me n tio n ed— Mr. Crampton . Mr. Crampto n was the

courage to submerge the first actual cable be tw e e n Englan d andFran ce , and, more than that, he was the mean s o f design ing


eve ry o n e laid sin ce, and w e can hardly be said to have departed

in fo rm from that early and first cable laid be tw e e n Eng

land and the co n tin e n t. True , there have be e n improveme n ts ino ther dire ctio n s— improvemen ts in the co re and in the strength o fthe exte rnal pro tectio n ; w e have had gutta-perchacove red w ireof various character

,and w e have also had tho se great impro vemen ts

made by Mr. Ho ope r ; but Mr. Crampton ’s w ire rope remain s the

type o f allsubmarin e cable s.

The pape r deals w ith that ve ry in tricate po in t co n n ecte d w ith thelaying o f cables, viz. the slipping back o f acable alo ng an in

clin ed plan e w he n it falls from the ste rn o f aship to the bo ttom o f

the o cean . The re are very fe w except tho se w ho have fo llo w e dthe subje ct mathematically w ho have succe eded in grasping theideao f this slipping back o f the cable . There is n o o n e w ho has

put it in asimpler fo rm than w as do n e by Mr. Gravatt in thisplace many years ago , w ho illustrate d it by achain falling o ver anin clin ed plan e . A cable falling at an angle thro ugh the w ate r

simply slips or slides thro ugh the w ate r as apiece o f paper slips o rslide s through the air (illustrated by apaper dart). To re sist thiste n de n cy to slip do w n it w as on ly n ece ssary to apply to the cable abreak po w er equal in w e ight to the length of the cable w hichw ould be suspen ded from the stern o f the ship to the bo ttom of the

sea.

No w ,in allthe se papers read at diffe re n t time s, un fo rtunate ly

w e have agreat deal o f the o ry and n o t much practice . The re aremany gen tleme n in this ro om w ho have be e n o ccupied in layin gthousands o f mile s of cable in de ep sea; but w e have n eve r had

any practical details of the break-po w er used,the variatio n o f

break-po w er acco rding to the depth o f w ate r, the angle w hich therope make s w ith the ste rn o f the ship o r w ith the ho rizo n

,o r any

facts w hich te nd to pro ve the truth o f the the orie s bro ught fo rw ard. I must say I w as in hope s, after the expe rience o f the

Me ssrs. Sieme n s in the Atlan tic and Medite rran ean, after the

experie n ce o f Mr. Webb and o f o thers in o ther parts o f the w o rld,

that w e should have had some practicalpro ofs of the truth of the sethe o re tical pro blems.

There is adiscrepancy be tw een the fo rmulas of Dr. Wern er

106 snam omc AND TESTING [8th March,

e lucidatio n before this So cie ty o n alate o ccasion , w hen Mr. Fahiegave apape r show ing ho w to e liminate tho se disturbing cause s

,

and e nabling us to arrive at the exact distan ce w hen aw ire isbroken . Though Dr. We rn er Siemen s has treated this subje ctw ith his usual thoroughn ess, I do n o t se e that he has advan ce dthe subje ct much further than it w as place d by Mr. Fahie .

Dr. Wern er Siemen s has n o t allude d to asubject w hich affe ctsus very much— that is, the durability o f submarin e cable s. It is

ve ry w e ll to lay and w o rk cable s, an d te ll us how far o ff they arebroken ; but allour kn ow ledge ‘

is o f little use un less w e are ableby some mean s to secure durability in the structure of the cable .

It is o n e thing to lay acable , it is an o ther to bring it to the surfaceagain . We have advan ce d very little from the first cable o f 185 1.

W e have altered the mate rials in the structure , and particularlytho se o f de ep seacable s, but I do n o t think w e have ye t reache dpe rfe ctio n . The last Atlan tic cable laid is asample of alltho sepreviously laid, and this fo rm o f de ep seacable is radically bad.

It do e s n o t give us acable o f such afo rm that w e can at afuturetime be certain that w e can bring it to the surface again . In the

Atlan tic cable w e have an outside co verin g of iro n w ire and hemp,

w hich in course of time must rust an d decay.

W e have hope s that amo ngst those engaged in the main te nan ceand co n struction of cable s some te legraph e ngin e ermay be foun d toin ven t acable w hich w ill e nable us to lay it w ith the certain ty o f

durability equal to that o f gutta-perchaitse lf. We kn o w practicallygutta-pe rchato be inde structible . There is n o pro o f of the de cay o rde te rio ratio n o f gutta-perchain sea-w ater. We shall n o t co n sidero urse lve s in the po ssession o faperfect de ep seacable till w e have o n eso pro tected by durable mate rials that w e can at any time raise it tothe surface if it should be required. I must, how ever, qualify theremark that gutta-perchais in de structible in sea-w ate r. I fo rgo t fo rthe momen t that the teredo had tasted its sw e ets. We have se en

spe cimen s in this ro om of the ravage s of marin e an imalculaandcr ustaceaupon gutta-percha the refore , I w ithdraw the statemen t

that it is inde structible , and w ill simply say that, till w e succeedin ge tting an outside coating fo r cables as strong as the presen tfo rm andas durable as gutta-percha, w e shalln o t reach perfectio nin the form of our de ep-seacables.

1m .) scm m TW RAHIS . 107

Mr. J . A. Lo no smo s,O.E . : I have be en kindly invited to

attend the meeting this eve ning ; and, w ith your pe rmissio n , I w illmake afe w remarks upo n the pape r w hich is under discussio n . I

w as n ot prese n t at the reading o f the pape r, and I have o nly hadthe o ppo rtun ity o f se e ing it sin ce last even ing, w he n I re ce ived aco py o f it ; co n se que n tly I have n o t be en able to read it carefullythro ugh . I w ill, ho w ever, make tw o o r three remarks upo n it

,

w hich,I

.

thin k, I am en titled to do,the mo re so as Dr. We rn er

Siemen s has re ferred to apaper w ritte n by my friend Mr. Bro o ksand myse lf

,and read in this ro om eighte e n years ago . It w ill be in

yo ur memory, Sir,and probably that o f o thermembers, that at thattime there w ere great do ubts w he the r acable could be laid alon gthe seabo ttom in astraight lin e . There had be e n adiscussio n bythe British Asso ciatio n at Dublin , in 1857, in w hich the co nclusio nwas arrived at that w itho ut infin ite velo city o f the ship such athing w as impo ssible . I w ill n o t go back to those old discussions

,

but simply refer n o w to w hat Dr. Wern e r Sieme ns says w ithregard to my paperHe says, “The mathematical part of the treatise is no t to be

disputed , and gives an accurate de scription o f the curve formedby acable suspen ded in an oblique dire ctio n in w ate r

,if paid o ut

w ith astrain upon the seabed.

”No w

,Sir

,that is the pro blem

un der its most gen eral fo rm . It is avery easy problem inde ed toso lve w hat w o uld be the po sitio n o f the cable if the re w e re n o

chain at the bo ttom . The o ther is amuch more complicate d problem , and Mr. Bro oks and myse lf fe lt that unle ss w e dealt w iththe ge n eral fo rm w e should be o n ly in vestigating an empiricalme tho d (w hich is n ot the course w hich scie n tific men gen erallylike to take ). The investigation must be to sho w the fo rm o f a

cable w ith astrain on the bo ttom. That in cluded the case w herethere was n o strain , simply by equalising the bo ttom te n sio n to

ze ro ; and there w e show ed distin ctly the cable w ould take astraight lin e . But Dr. Siemens go es o n to say :

“The physical

pm o f the w ork, and the practical co nsequen ces draw n from it,

are Ope n to grave o bje ctio n s.

”I scarce ly un derstand w hat he

means by ““

the physical part o f the w ork.

” As to “the prac

tical co n sequen ces draw n from it,” I am prepared to state w ithout

108 SUBMERGING AND TESTING [8th March,

fear o f co n tradictio n that allsubsequent practice— at least allsuccessfulpractice— has be en founded upo n prin ciple s sho w n in thatpaper to be mathematically the co rre ct prin ciples. We dealt thenw ith the various que stio n s w hich arise in the laying of alin e of

cable and w e have dealt w ith them seriatim . But Dr. Sieme n sgo e s o n to say, On e of the first prin ciple s taken for gran tedw hich materially influen ce s the results is in co rre ct.” That is agrave accusatio n fo ragen tleman in Dr. Siemen s’s po sitio n to make .

I agre e w ith the last speaker that it must be assume d he has go o dand substan tial reaso n s fo r making such an accusatio n . He refers

to the assumptio n w hich he says w e made that the frictio n o f a

cable sliding do w n through w ater w as propo rtio nalto the squareof the ve lo city, w hereas he asserts it really is propo rtio nal to theve lo city itse lf. No w a statemen t like that coming from Dr.

Sieme n s,9. man o f the highe st po ssible reputatio n

,must have

some basis, and it is to be regrette d that he has n o t po inted outw here in that basis consists. I w ill te ll yo u w here w e ge t our

datafrom,viz . Co lo n e l Beaufoy

’s experimen ts. He w as the o n ly

man I kn o w o f w ho made athorough se ries of experimen ts o n

the subject of the lateralfrictio n ofabo dy passing through w ate r.

I have refe rred to them and I find it varie s fi'

om to 19 47

that is practically n early as the square o f the ve lo city. But it do e sn o t altoge ther re st upo n that. This subje ct has been discussed inthe In stitutio n o f Civil Engin e ers mo re than on ce . There w as apaper read in 1857 by Mr. Armstro ng o n

“High Spe ed Navigatio n ,

”in w hich, o f course , the e lemen t o f surface frictio n w as co n

sidered ; and age n tleman fo r w ho se opin io n I have avery highre spe ct, and I think that is the case w ith allin this ro om

,Mr.

Haw ksley, past Pre siden t o f the In stitutio n o f Civil Engin e ers,

in that discussio n state d distinctly that the re sistan ce o f bo diespassing through w ate r varie s exactly as the square o f the ve lo city,and n o pe rso n in that discussio n , and it w asavery lo ng o n e , inany w ay con tradicted Mr. Haw ksley

’s statemen t.

Again , in 1866, Mr. G. H . Phipps, member o f the In stitutio n of

CivilEngin e ers, readapaper o n “The Resistan ce of Bodie s passingthrough Water,

”in w hich he referred to Beaufoy

’

s experime n ts,show ing that the re sistance w as proportionalto the pow er 01


under the same con ditio n s. That also w e so lved , and adde d tw oo r thre e co rrollarie s show ing : (A) The ve locity at w hich the cableruns o ut vertically w itho ut te n sio n ; (B) The angle at w hich thecable w ould run out w ith the greate st ve lo city ; (0 ) The w aste of

cable w he n it run s o ut at any given angle fre e from te n sio n ;(D) The angle o fmo tio n of the end in case o f fracture . The thirdproblem w as the ge n eral equatio n to the curve

,from w hich w e de

duced that the cable de sce n ds in astraight lin e w hen the bo ttomte n sion is zero . The fourth problem w as the equatio n for te n sio nw hat Dr. Siemen s calls the brake -po w er. We sho w ed in tw o table sthe reductio n o f te n sio n caused by run n ing o ut certain amoun ts o f

slack, applicable bo th to aheavy cable and to alight o n e . The fifthproblem show ed the w aste o fcable in passing thro ugh curren ts. The

sixth w as the equatio n to the curve o f alin e strain ed acro ss acurre n t. The seven th w as the ten sio n due to the frictio n o f w ate r o n

a curren t coming acro ss the lin e o f acable . The e ighth w as thefo rm w hich the cable w o uld assume and the re sulting te n sio n sup

po sing the paying-out apparatus w as sudden ly stopped in the act ofpaying out. The n in th problem w as to find the po rtio n o f the e nd

o f acable at any give n in terval o f time afte r fracture . The te n thw as the exte n sion o f le ngth due to the compre ssio n of the in n erco re . The last problem w as the inve stigatio n of the variatio n of

ten sio n due to pitching and the moveme n t o f the ship in aheavysea, and the mo tio n o f the paying-o ut apparatus. We furtherin ve stigated the effe cts o f floats o n re sisters, and the mean s o f

saving cable in case o f fracture . These w ere the prin cipalproblems w e so lved. We so lved them w ith mathematical co rre ctn e ss ; and, from allI have se e n since , I be lieve the re sults w e

arrived at w ere practical and re liable re sults, and n o t, as some say,the o retical re sults. Therefore , I say again , Dr. Wern e r Sieme n s,in saying there w as n o t aclear pe rceptio n o f the prin cipalfacto rs

,

has go n e furthe r than he o ught fairly to have go n e , and that w ehave treated the subject far mo re in exte n so than he himse lf hasdo n e

,and w ith, I be lieve , greater accuracy. So far as I have

se en , the o nly differe n ce he has made is assuming the frictio n to besimply as the ve lo city and n o t as the square , and that, I be lieve , isan error. With regard to Mr. Gravatt, he simply show ed the

SUBMAR INE TELEGRAPHS . 111

questio n o f achain lying over an inclin ed plan e w ith part o f thechain do w n the in clin e and the o ther hanging o ver the and

vertically . That w as avery e lemen tary pro blem o f mechan icalscience— that the tw o w illbalan ce ; but to say that it solved thequestion w ith regard to telem ph cables is go ing alittle to o far.

The re is o n e po int I w ould draw atte n tio n to , viz . , the co nclusion w hich w e arrived at as to the abso lute n ecessity o f layinglight cables. What I ve ntured to state e ighte e n years ago hascome true ; and the evil o faheavy cable has be e n attempte d to beremedied in aw ay I do n o t approve o f

,viz . , by making aheavy

cable , and the n making it light by putting o n hemp . Te n years

ago I predicted that if aheavy cable , afte r be ing laid ayear’

o r

two, happen ed to break in fathoms of wate r, you w ould n o t

beable to ge t it up to the surface . I still be lieve so . I think o n e o f

the Atlan tic cables , tw o o r thre e years ago , happe n ed to take thatfreak in fathoms . I think it w as the 1865 cable ; but, as farasIlmow , that has n eve r bee n brought up. They have tried to bringit up mo re than on ce , but failed, and I be lieve they w ill n eve rsucceed, fo r this reason : the iro n , be ing in astate o f oxidation , iseven heavier than be fore , and it has lo st its stre ngth ; the hemp isgone ; the re is n o stren gth in the thin g ; and w hen you try to liftit it breaks. If the cable is required to be lifted immediate ly afte rit is laid, but possibly be fore the iro n corro des, yo u can do it. Aheavy cable is n ot o n ly more expe n sive in first co st

,but it takes a

large ship to lay it. I main tain t hat about afive-e ighths diame te rcable might be made w ith the same co nducting pow er, and co uld belaid more safe ly,and could be go t up w ith greate r ease . I should liketo see cables payed o utas log lin es from aship. The pro per apparatus is o n e w hich pays out the cable w ith the propo rtio n o f slack

yo n w an t, no t o n e w hich ho lds it in . Some years ago I had themodelof amachin e , w hich I sho w ed to the Jo in t Committe e o n

Tehegraphs, as w ellas some draw ings o f an o ther system,w hich

w as made to imitate the actio n o f aman ’s han ds. It w as so

arranged that the cable passed thro ugh tw o lo ng be lts w ith acertain amo un t o f frictio n . If the ship pitched heavily it slid thro ughtlse belts ; in case of a kink the machin e o pen ed and allo w edthe kink to pass, and the cable was then replaced in the apparatus.


By this mean s the cable w as draw n o ut o f the ho ld an d paye do ve rboard . With alight cable there w o uld be comparative ease in

ge tting it up but I do n o t think you w ou ld require to ge t it up.

The reaso n w hy the 1865 cable broke , I have n o doubt, w as its

be ing laid o ve r akind o f valley, and it hung acro ss this valleylike the chain o f asuspen sio n bridge . As lo ng as the w ire he ldgo o d it w as allright ; but w hen that ruste d the catenary strain

broke the cable , and do w n it w e n t. Fe e ling this,as I have do n e

fo r many years, I have alw ays be lieved that the day w ill comew hen w e shall abando n allthis heavy w ire round the cable ; thatit w ill con sist o n ly o f the copper w ire and pe rhaps fin e ste e l w ire sboun d in side the gutta-pe rchaand pro tecte d by some mate rialsufficie n t to pro te ct it un til it has go t safe to the bo tto m . Sup

po sing suchacable is laid w ith adue amoun t o f slack— n o t hangingove r precipice s— the n I be lieve w he n yo u ge t acable like thatlaid in fathoms, you w ill n eve r requ ire to touch that cableagain .

Mr. WM . HOOPER : The last observation o f the ge n tleman w ho

has justaddre ssed us is e n titled to con sideratio n— that is as to thedurability o f cable s. There is n o difficulty in submerging them if

you o n ly ge t the right sort. I do n o t pay much regard to the que stio n w he ther yo u have apparatus o r n o t. Yo u must lay such acableas can be raised fo r afault, and w here the spe cific gravity is n o t somuch tho ught o fas the externalco vering o f the cable . If yo u haveiro n w ire outside the core the w ro ught iro n lo se s stre ngth andafteratime it be come s aburden mo re than an assistan ce . It is n o t

required in sinking acable to have ironw o rk at all. The decay o f

iro n w ire under w ate r has be e n e stablished, and therefo re the greatpo in t is to ge t an inde structible in sulato r, and w ho ever is clevere n o ugh to find out ago od covering to ago od in sulator w ill accomplish w hat has n o t ye t be e n attain ed. My name has be enme n tio n ed in co n n ectio n w ith this subje ct. I should have be e nglad if w e had carried o ut o n e e lemen t in cable s w hich MajorChampain brought befo re us afew w e eks ago , viz. , an in sulato rw hich w ill last. Marin e insects do bore in to gutta-percha

, and I

should have be en glad if Mr. Pre ece had commun icate d the factthataform of in sulator has been discovered w hich is n o t injured

114 SUBMERGING AND TESTING [8th March

w ill be seen by re so lving the fo rce s that astrain o n the cable o f

10 to n s w ill o n ly give an upw ard strain o n the sheave A o f 5 to n s,

the leve r A B 0 having aleverage o f 5 to l,the strain at C o n

the Salter'

s Balance is o n ly o n e-fifth o f this,o r 1 to n , so that

e very po un d sho w n o n the Salte r’s Balan ce indicates 10 lbs. strain

o n the cable . The in strumen t has its advan tage s ; it is muchlighter than the o rdinary dynamometer

, and lie s much lo w e r.

There is n o heavy w e ight dan cing up and do w n , and there is n o

changing of w e ights and scale s required,many hundred m ile s o f

cable having be en laid w ith this dynamometer. The Fren chGovernme n t have adopte d it in repairing ships.

With regard to the que stio n o f light cables,Mr. Lo ngridge ,

w ho I have befo re had o ccasio n to me e t,and fo r w ho se pape r I do

n o t suppo se anyo n e has agreate r re spect than I have myse lf, hasspoken as an e ngin e er about our employing light cable s

,and Mr.

Ho ope r has spoke n o f light cables ; but allw ho are engage d insubmari n e te legraphy kn o w that this is o n e o f the problems ye t tobe so lved . Whe n pe ople say , Oh I lay dow n amere copperw ire in sulated w ith gutta-percha, they do n o t co n side r that if yo uhave such acable as that it w ill break. I have made experime n ts

w ith regard to the breaking-strain o f seve ralkinds o f coppe r w irein sulated w ith gutta-pe rcha, and in every case it came o ut equal toabo ut the w e ight of tw o m ile s o f the w ire and gutta-perchain w ate r

,

so that if yo u stopped the ship in tw o m ile s depth o f w ater the cablew o uld simply break ; the que stio n is, w hat you are to put ro un d itto make it so that you can lay it, in the first place ; and then yo umust allo w this -that w ho eve r has to layacable , o r w ho evermake sit, yo u may have fau lts, w hich o ccur from vario us cause s, andthere fo re yo u must be prepared to sto p the ship and haul back thecable , and this may have to be do n e in heavy w eather therefo regutta-perchacove re d coppe r w ire alo n e w illn o t suffice . The n yo ucome to the que stio n o f hemp placed o ve r the gutta-pe rcha. Thatis aque stio n w hich is open to discussio n

,an d there are cases in

w hich it has be e n fo und that hemp increase s the liability o f the

lin e to kink, and thus make s it difficult to co il. These are allquestio n s w hich have ye t to be so lved. It is allvery w e llto talkabo ut light cable s, but let some o n e bring us apattern o f cable that

SUBMARINE rm csarns . 115

can be take n from the facto ry, co iled and w e tted, and laid to dry,take n o n board ship and laid do w n , and, if n ece ssary , haule d backw itho ut breaking . Whe n anyo n e brings such aspecimen o f cableforward ,le t it be discussed. But up to this time ,as far asmy expericuce gee s, I have see n n o thing w hich satisfie s these co ndition s.Mr. Tnxum u n : Mr. Varley, afte r describing briefly the ex

ternal co nstructio n o f an Atlan tic cable,says

,No w the w ho le o f

this pre sen ts asmo o th exterio r, but the momen t the cable is passedroun d the drum it be comes flat in shape and you have anumbe r o ffibre s sticking o ut o f the cable . We n o w find the cable bristling allove r w ith filamen ts . I do n o t kn o w to w hich Atlan tic cable Mr.

Varle y re fers, but the cable that be come s flat o n the drum must be

inhe re n tly de fe ctive . Ne ithe r do I fo llow Mr. Varley in his drawing o f w hat may be te rmed a“po rcupin e cable ; ” there may befibres visible upo n clo se examinatio n , but they ce rtainly are n o t o f

the exaggerate d pro po rtio n s that I understand Mr. Varley to givethem.

We allkn ow that w e ll-manufactured cable s have be e n raised o utof the dee p seaafte r having mon ths’ immersion and did not showany sign s o f flatn e ss or filame nts, but looked as perfe ct as w henin the manufacture rs’

tanks.

I pe rfectly agre e w ith the remarks made this even ing by o ur

w o rthy Preside n t,that the le ngthy argumen ts o n prio rity w hich

fo llo w ed the reading o f the pape rs have be e n rathe r o ut o f place ,but I think the fault lie s o n the side o f tho se w ho raised the questio n and n o t those w ho an sw e red them. I have several remarksw hich I in te nded to bring against the le ngthy histo ricalargume n tso f forme r speakers, but fo llow ing the Presiden t

’

s de sire I w ill o nlysum up the co nclusio n to w hich Iarrive andadd afe w w o rds w hichought no t to be fo rgo tten in this discussio n , viz . that at the periodw hen th e Russian Go vernme n t w asmanufacturingand laying undergro un d w ires, the n e cessity fo rmethods o fmeasurem ents, resistan cestandards, and me thods fo r the de te rminatio n o f faults

, aro se and

w as o ve rcome by Dr. We rn e r Siemen s, w ho used such me thodsand e stablishe d the rule s fo r te sting as w e ll as creating the un itof re sistan ce , and handed ove r the se me thods and un its to the

ele ctricians o fEnglish man ufacture rs o f submarin e cables.I 2

116 SUBMERGING AND TESTING [81h March ,

The first methods fo r te sting w ire s e le ctrically and de te rmin ingfaults w e re publishe d by Dr. We rn e r Sieme n s at the me e ting o f

the great “Academic de s Scien ce s,”29th April

,1850, in cluding

the law s o f e lectric charge and discharge in cable s. The se inve stigatio n s w ere also prin te d in the archive o f the greatAcademic,also in “Berlin Physicalischen Ge se llschaft,

"18th January, 1850,

and in Poggendorf’s An nalen ,

”vol. 75

,1850. In the latte r

publicatio n (at page 497) lightn ing -pro te ctors w ith plate s o r

po in ts w ere men tio n ed fo r the first time,an d the in sulatio n o f a

lin e fo r the first time give n in im its of re sistan ce . Also the first

formulae and methods fo r the de terminatio n of faults are given o n

page s 493and 494 ; finally the law s o f e lectrical charge s in undergroun d w ire s page 499.

I agre e w ith Mr. Willoughby Smith that it is a curio usfact the great philo sopher Profe sso r Faraday brought befo re thepublic as a n ew thing, in ve stigatio n s re lating to gutta-percha,w hich Dr. Wern e r Sieme n s had previo usly published. Faradayre-discovered Sieme n s’s law s o f charge s, but he afterw ards ackn o wledged Dr. Siemen s’s prio rity w ith regard to the same .

If w e n o w co n sider that the laying do w n o f de term in edme thods and fo rmulas fo r the expressio n o f e le ctrical re sistan ceand the fin ding o f faults n o t o n ly started from the pen o f Dr .

Wern er Sieme n s, but that these very me thods, w hich w e re n ece s

sarily bro ught in to life during the manufacture and laying o f the

thousands o fm iles of gutta-pe rchaun derground w ire s in Prussia,afterw ards fo rme d the base fo r submarin e te sting, and if w e co n

side r that tho se Prussian un dergroun d w ire s w ere made w ith amachin e fo r the same prin ciple as tho se o f o ur days, and thatgutta-perchaw as re commen de d and adopted as an in sulating mate rialfo r cable s, then I think every impartial judge must come to

the co n clusio n that, I be starting p oin t of submarin e telegrap hy is

to befound in the subterran ean lines constructed in P russiaduringthe years 1847

The PRESIDENT : This n o w brings to aclo se amo st valuablepape r and in tere sting discussio n . I have n o further remarks too ffe r o n the subject, n or even if I had w ould time le t me , fo r o ur

118 SUBMERGING AND TESTING [8th March

[APPENDIX ]

NOTES o n Dr. WERNER SIEMENS’S PAPER “On SUBMERGING and

TESTING SUBMARINE TELEGRAPHS .

”

Th ese n ote s are obliged to appear in the ir present form,as I was

unable to attend the adjourn ed me etings on the discussio n of Dr. Sie

men e’s paper.

There are three distinct kinds of faults w hich may happen to the

1st. Rupture of th e co nducto r w ith the ends of the copper inclosedin the insulating envelope , so as to give partial or complete insulatio n on on e or bo th sides o f the break.

2nd. Rupture of the co nducto r w ith the ends inclo sed in the insulator, and giving partialo r in termitten t con tact.

3rd. Rupture of the conductor w ith o n e or bo th ends coming in

contact w ith the water.

The measuremen ts for the position of the rupture by mean s of dis

charge tests are w ell kn o w n , and o n shore can be easily carried out ; but

o n board ship and w ith marin e galvan ome ters it is n ot so easy nor so

certain to arrive at the exact po sition . At seaI have fo und the bestplan to be , w hen using the capacity test, to read w ith as small asw ingof the mirro r as po ssible and, w hen comparing the discharge from the

cable w ith that from aco ndenser, to vary the shun t resistance so as to

obtain as n ear as po ssible the same range of sw ing.

The metho d po inted out by Dr. Siemens in measuring aseries of

abstracted charge s from the cable is eviden tly of no value if the cablegives much le ss at the break, o r if the cable itself leaks fast. Apart

from these objectio n s, the accumulated po ssible erro rs in the result

w ould, I should imagin e , be of some impo rtance .

In dealing w ith acase w here the lo ss is n o t very great, o r at least sosmallas n o t to be perceptible during the time o f taking an observatio n

,

I kn o w o f n obetter plan than using apo rtable electrometer, the indica

tion s o f w hich can be read quite independently o f the mo tio n o f the ship ,or th e length of cable under te st. The plan is first to approximate by

187'


discharge the position o f the break ; then con n ect up aseries o f con

dense rs, or some lengths of Spare cable approximate ly equalto th e indiosted capacity, w ith apo rtable e lectrometer and battery. The readingbeing taken

,the battery is removed

,the charged spare cable o r con

densers be ing left co n n ected to th e e lectrometer. The end of the cableto be te sted, previo usly discharged, is n ow applied to the e lectrometerand co nde nsers, and the reading again carefully n o ted, from w hich the

po sitio n of the break is mo st easily and reliably fixed upo n .

It is the simplest and mo st certain proce ss to obtain the measuremen t

by halving, if po ssible . Thus, suppo sing w ith the co nden sers and elec

trome ter the reading was e ighty turns o f the micrometer screw ,and w hen

the cable was conn ected up it fe ll to forty, the capacity of the conden sersw ill be exactly the capacity of the cable to the break, the capacity of

the e lectrometer be ing so small as to be n eglected.

The case of partialor in termittent con tact is an extreme ly unpleasan t

on e , and requires -very great care . With vulcanized rubber co re s the

simple st plan is to have acurren t flow ing through the cable . After a

time the ends become coated w ith acomparative ly in sulating film o f

sulphide , w hen an inductio n test can be applied.

Wh en the tw o ends can be got at, and the resistance at the break is

n o t high en ough to depend upo n the result o f asimple discharge test,the be tter plan is, first, to charge the cable at bo th ends

, and n ote th e

discharge , then take the discharge from each end separately . No w,as

w e are like ly to charge up bo th po rtio n s o f the cable , the tw o dischargesadded w illbe greater than w hen

’

th e tw o ends w e re tested together.

Suppose , fo r example , w ith the tw o en ds togeth er our discharge equals100 , and w ith o n e end o n ly w e get 70 and o n the o ther 40, w e have todivide 100 in to tw o parts, having the ratio o f the se numbers fo r the

capacity o n either side to the break. How ever carefully the test be madethe actualpo sition of the fault w illalways be n earer to the end on the

sho rter side . The higher the re sistance at the break the more n early w illthe actual po sition of the break co incide w ith that indicated by testing.

Probably by measuring charge instead o f discharge be tter results may beobtain ed.

In the third case , w hen the ends are exposed to the water, it has be en

propo sed to coat the ends w ith asub-chlo ride o f copper by mean s o f th e

curren t , and to measure the discharge . I have n o t ye t me t w ith any

me thod fo r dealing w ith this kind o f break w hich can be co n sideredsatisfacto ry, and more especially if the Operatio ns are carried out o nlyat


o n e end. In lo calising such afault, and in fact in dealing w ith all

faults gen erally, n o precise lin e of action can be marked out ; mo re

must depend upon tact and perseverance than on any prescribed regulation as to testing.

The earlier tests taken on abroken cable are always more likely to beusefulfo r pron ouncing o n its po sitio n than tho se taken after the lapse ofa longer time , partly from th e co rro sion of the copper, or the conductor

be ing taken away for ashort distance inside the in sulato r, w hich w ill

increase th e re sistance en ormously. If acable has taken afew days tobreak asunder, as happen s un der the actio n o f achafing o r abraidingmotion

,the tests

,if the cable has previously to breaking show ed indica

tio ns of be ing faulty, w illbe of great assistance . In this case systematictesting from both ends should be immediate ly commenced ; and such

time for testing Should be selected w h en the cable is least disturbed byearth curren tsf

By these precaution s afault was localised in the éable betw e en Paraand Cayenn e , w hich ultimately resulted in abreak. The day o n w hich

interruptio n first show ed itse lf was occupied in te sting and w ith satis

factory te sts as to the po sition o f the fault ; but, although the cable was

tested several w eeks afte rwards, n o t asingle test could be obtain ed

from e ither end w hich was o f the slightest value so that,although

this fault was n o t removed untilFebruary, I elected to act upo n the

tests taken in Octobe r for the place of operatio n . Whilst signals could

be tran smitted each station exchanged their results every day, so that

the repairing steamer calling at o n e statio n had the datafo r operatingw ithout the n ecessity of go ing to the o ther end of the lin e .

In measuring the re sistances for such afault,as w e llas fo r extensive

in sulation faults, it is best to bring the fault by means o f the battery to

as co nstan t acondition as po ssible . The pow er required fo r this must

depend upon circumstances ; it is as diflicult to w ork upo n avery open

fault as it is o n asmalland varying fault. Having fixed upo n the

number o f ce lls be st suited, the re sistance is carefully measured, w hichby reversed currents and earthing alternate ly can frequen tly be madecon stan t. If the cable is much disturbed by earth currents o r the

ch emicalaction at the fault, it is better to measure the resistance byn o ting th e deflection s on adead-beat galvan ometer, recording the deflectio n s at frequent and short in te rvals w hilst the battery is o n , an d thenfo r the same and similar in tervals o f time taking the deflectio n s o n the

galvan ometer w hen th e cable is to earth, adding or subtracting the sum

122 SUBMERGING AND TESTING [22nd March ,

The Fo rty-sixth Ordinary Gen e ral Mee ting w as he ld o n Wedn esday ,the 22nd March

,1876

,Mr. C. V.WALKER

,F.R S. Pre side n t,

in the Chair.

The PRESIDENT : The discussio n o n the pape r On Submergingand Testing Submarin e Te legraphs by Dr. Wern e r Sieme n s w asn ecessarily clo sed at the last mee ting w itho ut the usual reply andremarks o f the autho r of the paper. Dr. Sieme n s is n o t in this

coun try, but he has se e n the n o tes o f the discussio n an d has se n t

areply thereto in additio n to the commun icatio n already read(p. This w ill n o w be read before w e en ter upo n the o the rbusin e ss o f the me e ting .

The ACTING-SECRETARY then read the follo w ing commun icatio nfrom Dr. Wern er Siemen s

Mr. J .A. Lo ngridge has at the mee ting o f the So cie ty upo n the8th o f this mo n th (March) subjecte d my pape r to severe criticism.

Mr. Lo ngridge says that I have o n ly adopted his w o rk o f e ighteenyears ago , and sugge sts very plain ly that my ideas and fo rmulaeare mere tran spo sitio n s from his o w n

,under simpler co n ditio n s

arising from an e rro n e o us in tro ductio n o f the sliding frictio n o f

w ate r. In an sw er to these severe reproache s I have to e n te r in tothe matte r mo re particularly .

The treatise o f Me ssrs. Lo ngridge and Bro oks is,so far as I

kn o w,exclusive ly published in The P roceedings of the I n stitute of

CivilEngin eers, vol. xvii . fo r 1858, co n sequen tly o n e year later

than the demo n stratio n and employme n t o f the the ory by me o n

the first successfullaying o f ade ep seacable , that o f the B o na

Cagliari cable . This the o ry w as founded o n the suppo sitio n of

the falling cable takin g astraight lin e,and the sliding frictio n in

the directio n o f the cable -laying be ing simply proportio nal to thesliding ve lo city. Mr. Lo ngridge is the refo re scarce ly e n titledto assume that the first ideahas be e n adapted from his treatisepublished o ne year later.


It is to be regre tted that, so far as my kno w ledge go es, Me ssrs.

Lo ngridge and Bro oks’ paper has n o t appeared in agen erally

accessible scien tific journal, and this explains ho w it is that Iderived, o n ly in the summer o f 1874 , on board the “Faraday,from o ur e ngin e er Mr. Brittle

,the kn o w ledge of the existen ce of

this treatise at atime w he n my ideas had lo ng since bee n fo rmed.

As in the scie n tific w orld it is customary that the right o f priority

of my in dependen ce , ackn o w ledged the right o f the priority of

Me ssrs. Longridge and Brooks in the pure ly mathematicaltreatme nt of the subject, and I have co nfin ed my o w n claims to the

Mr. Longridge should be thankful that I have w ithdraw n his

That my formulaand co nclusion s are n ot co ntain ed in his,follow s

as ase que nce from the fact that I am declared to have w ro nglystate d on e o f the principal facto rs o f the calculatio n— th e law o f

the sliding-frictio n in w ate r— w hich Mr. Lo ngridge has acceptedand for w hich I have substituted an o ther. Mo reo ve r

, te legraphengin eers experien ced in cable laying w ill be be st able to judgewhethe r the se formulaand tables are the same

,and are n o t mo re

readily practicable than those give n by Messrs . Lo ngridge andBrooks. No tw ithstanding this, my differen ce from Mr. Lo ngridgeconcentres itself in the questio n upo n the law o f sliding frictio n inWater.

Mr. Lo ngridge finds the expre ssio n used in the English tran slation of my paper, the physical part o f the w o rk,” in compre o

hensible . I w illingly co n cede him to be right in this,as it is a

tee literal translatio n o f the German te xt. In Germany by thetermphysik is understo o d w hat 18 kn o w n in England as NaturalPhloem . The in te n tio n w as to express that his treatmen t w asto farmathematically co rrect, but that the fo undatio ns o f the calcuhfiunsand the refo re the results o f the calculatio n s w e re inco rrect .Mr. Lon gridge co n te sts this, and se eks to pro ve the co rre ctn ess

Ofhis ideas from give n autho rities , and blame s me fo r the facilitywith w hich I declare e rror

,w itho ut proving by experime nts alaw

commo nly accepted as co rre ct, to be in correct.

124 SUBMERGING AND TESTING [22nd March ,

He also finds it absurd to accept adifl'

e ren t proportio n o f the

frictio n at the in side and at the o utside o fatube .

I ve ry w e ll kn o w that practice has e stablished empirical fo rmulae

fo r the frictio n o f liquids in lo ng tube s in w hich the ve locityappearsat the same time in bo th the square an d in the first po w er.

Similar empirical formulae are also e stablished fo r the mo tio n o f

w ate r in chan n e ls and open gutters, and the se are un do ubtedlycorrect to the exte n t o f the expe rime n ts o n w hich they are based.

Eytelw e in has the o re tically based the quadratic law fo r the flo w

through tubes o n the view that w ith double the ve lo city tw ice asmuch adhering w ater must be to rn aw ay w ith tw ice the rapidityfrom the side s o f the tube . He has n o t co n sidered that the w ate r

o n the side s o f the tube do es n o t flo w at all,but remain s w itho ut

mo tio n ,and that the ve lo city in crease s gradually to w ards the ce n tre ,so that aco n cen tric stratum o f w ater thrusts itse lf fo rw ard o n theadjacen t strataw ith le ss ve lo city . In tube s o f smaller diame te r andw ith n o t t o o great w ater-ve lo city w e o btain , as has be e n o fte n

ascertain ed , an o utflo w o f w ate r w hich is dire ctly propo rtio nal tothe p re ssure difference . I myse lf have sho w n this to be n u

doubte dly the case by ale ngthy se rie s o f experime n ts publishe d inThe German Telegraph Jour nal, vol. xiii. o f the year 1866. The seexperimen ts w e re made fo r the purpo se o f sho w ing the practicabilityo f such lo ng pn eumatic tube s as w ere in te n ded for use in Berlin

,

and w hich w e re carried o ut. That w ith w ide tubes and highcurren t ve lo city the re appears aquadratic-ve lo city factor, be sidesthat o f the first degre e , is accoun ted fo r by the liquid vo rtice sarising in the tube s by w hich vis vivais co n sumed. T he same thingo ccurs w ith the mo tio n o f w ate r in chan n e ls and w ith o ther practicalexperimen ts from w hich surface -frictio n has be e n con cluded .

But I am obliged to compare the authorities quo ted by Mr.

Lo ng ridge w ith others w ho se compe te n ce he w illscarce ly doubt :

Sliding Friction in L iquids .

Ne w ton (PrincipiaMathematicaPhilo sophies, lib . 11 . sec. 9,1687)

says that the frictio n exerte d by tw o stratao f fluids mo ving in thesame directio n is propo rtio nal to the diffe re n ce o f the ir ve lo citie s

,

and in propo rtio n to the co n tact-surface s o f the tw o strata.

126 SUBMARINE TELEGRAPHS . [22nd March ,

derived from vortices w hich at greate r ve locitie s o ccur through theshaking o f

,and the irregularitie s in , the tube . The effect o f t he se

vo rtices upo n the ce n tral flo w in the tube must be much mo re

impo rtan t than that o f the vo rtice s upo n the cable w hich may arisefrom the cable itse lf. Then , also , in the case last men tio n ed thevortice s can e scape o n allside s ; in the first case they me e t theresistan ce o f the tube .

The re is,ho w ever

,n o groun d fo r the acceptation o f vo rtice s, as

the case o f the sliding cable is w ho lly comparable w ith mo tio n inthe capillary tube . And this mo tio n is in acco rdan ce w ith theacceptatio n o f the case o f cylin ders sliding o n e upo n an o ther.

Mr. Lo ngridge w illun derstand from this that I have n o t, as hethinks, frivo lo usly o verthro w n acommo n ly accepted prin ciple andsubstituted o n e upo n o the r mo tive s. He has committe d the com

mo n error o f e n larging to to o great an exten t upon the basis o f expe rimen t. But I had in the year 1857, w he n I fo rmed my theo ryof cable laying, co nvin ced myse lf by dire ct experimen t thatwith themo tio n o f arope in astraight lin e in w ater the ve lo city pro duce sadire ctly pro po rtio nal resistan ce . I had

,thro ugh ape rfe ctly calm

sea, alog-lin e dragging astern o f the cable-ship,the lin e be ing

faste n ed to a spring-balance . The ve lo city o f the ship w as measured by mean s o f an o rdinary ship’

s log ; the re sistan ce measuredin kilogramme s agre e d exactly fo r diffe re n t ve lo citie s o f the ve sse lw ith the spe ed sho w n by the log. Mr. Lo ngridge can , by thisexperimen t, easily co nvin ce himse lf o f the co rre ctn e ss o f my

assumptio n and o f the incorrectn ess o f his fo rmula. But I advisehim to make this expe rime n t in calm w ate r o n ly

,be cause eve ry

w ave -mo tio n give s in co rrect re sults. I hope Mr. Lo ngridge w illcomprehend that he has go n e to o far in the defe nce o f his fo rmula,and w illackn ow ledge the injury he has do n e me .

”

The PRESIDENT I have n o w to call upo n Mr. Langdo n to readhis pape r w hich has be e n an n o un ced fo r this eve n ing upo n asub

jce t w hich , at the pre sen t time,is practically in te re sting

, v iz . 0 11

4‘Ele ctric Repeate rs fo r Railw ay Signals.

”

ELECTRIC REPEATERS FOR RAILWAY SIGNALS.

ByMR . W . LANGDON,

Superin tende n t, Post Ofi ce Telegraphs .

Atte n tio n has re ce n tly be e n directe d, in avery fo rcible mann er,to the employme n t o f e lectricity fo r repeating back to signalme n ,and o the rs

,the co nditio n o f the signals w o rked by them fo r the

con trol of traffic o n railw ays. It w o uld appear that o n e o f tw o

course s is n e eded : e ithe r that signals themse lves shall be so co n

structe d as to be rem oved from the influe nce o f the e leme n ts, o rthat some mean s shall be adopte d by w hich the co n ditio n o f the

signaF- the arm

,o r disc

,by day, an d the light by n ight— may be

brought clearly be fore the man w ho is answ e rable fo r its due

To alter the fo rm o f signal in use upo n any lin e o f railw ayw ould n ot o n ly be aque stio n of considerable expe nse but also o ne

of som e difficu lty. Mo reover,it is do ubtful if asystem could be

found w hich w ould prove in depen de nt o f tho se freque n t and o fie n

violen t atmow heric changes of w hich w e have o f late had suchample expe rie n ce . The prese n t system o f w o rking signals is undoubte dly that w hich w o uld recomme nd itself to every practicalmind as the best fo r gen eral use . At the same time it is eqnallyeviden t that it must be subje ct to every change o f

’

temperature .

During ahot day the w ire by w hich the signals are w o rkedexpands, and unde r the colder atmo sphere o f n ight it again con

tracts. A ehange in the w ind from aw arm to ae old quarter w ill

have the same effe ct. Some tw o mo n ths sin ce the autho r w atchedthe w orking, o r rather attempted w o rking, o f adistan t signal fo reveran ho ur, durin g w hich,' altho ugh the leve r in commun icatio nw ith it w as o perate d in the usualmann er

, the arm n ever o nce

moved from the cautio n po sitio n . And although it may se em

strange , it is ye t afact ; the day w as beautifully clear, and theSignal, w ithin easy vie w o f the statio n , w as n o t obse rved by e itherthe statio n agm t o r the perso n w ho profe sse d to be w o rking it. It

128 ELECTRIC REPEATERS FOR [22nd March,

is que stio nable if such co uld have be e n the case had the man hadplaced in fro n t o f his lever arepeate r to sho w w he the r the armro se to danger o r n o t. The w eather during the day in que stio nhad be e n w arm in the mo rn ing

, but the w ind,having change d from

the south-w est to the n o rth-east,w asthen bitte rly co ld. Do ubtle ss

the signal had,as w as stated

,bee n w o rking allright during the

early part o f the day . To box in w ire s w orking such signals w ouldpreven t the ir be ing loaded w ith sn o w

, but it w ould n o t pro te ctthem from change s o f temperature

,although itmight he lp to d o so

the arms themse lves might be w o rked w ithin acase,but they w ould

lo se the ir pre sen t clear and defin ed form,and in sn o w -sto rms the

covering itse lf w o uld probably accumulate the sn o w mo re than thearm

,w hich it w o uld o bscure , and so in itse lf be come mo re asource

o f dange r than pro tectio n . Le t asignalw o rk ever so badly,if the

signalman is made aware o f it he has mean s by w hich he can pro

vide again st its in operatio n pro ving asource o f danger . This iseffe cte d by w hat is kn o w n as the Ele ctric Re peate r.

”

There are tw o fo rms of repeaters, viz .

, that fo r the arm o r disc,and that fo r the light.The arm-repeater w as in troduced by Mr. W . H. Pree ce , w ho

saw the n e ce ssity for it, in 1865,and te sted it by tempo rarily

applying o n e o f his semapho re blo ck signal in strumen ts to adistantsignal n ear Lo ndon . A combin ed arm and light in strume n t

,

the jo in t inven tio n of Mr. Pre ece and Mr. A. Warw ick, fo llo w edshortly afterw ards. In strumen ts fo r e ither purpo se , o r

.

fo r the

tw o combin ed,are n o w in use o n several railw ays— the Lo n do n

and So uth We stern,Great No rthern , Lan cashire and Yo rkshire ,

Great Eastern , &c. ; but the ir applicatio n has n o t be en so ge n eralo r so rapid as recen t circumstance s w ould appear to ren derdesirable .

The in strumen ts are of diffe re n t fo rms, of differe n t make s, an dare applied to the signal itse lf in differe n t w ays. It is w ith theo bject of de te rmin ing the prin ciple s upo n w hich such in strume n tssho uld be made , applied, and w o rked

,that the autho r submits the

fo llo w ing remarks fo r the co n sideratio n o f the So cie ty, and w ith

this vie w it is propo sed to deal w ith the questio n in the fo llo w in gorder

130 ELECTRIC REPEATERS FOR

required. To o ne e nd o f the e lectromagn e tic co ils is conn e cted

(fig. the o ther po le of w hich is to earth, and to the

P 1 6 .

QE O C A‘

T E

o ther end o f the co ils the e le ctric w ire B , in co nn ecti o n w ith thesignal-po st. At the po st this w ire is carried to aspring C , fixedin clo se proximity to the signal-arm . To the back o f this arm is

fixed apiece o f me tal D,and immediate ly above an o ther spring

E,from w hich aw ire passe s to earth. The repeate r may be

so co n structed that the arm shall fall,by gravity, to allclear,

or it may be made to rise to danger by the same pow e r. W e

w ill assume that it is co n structed o n the forme r prin ciple , w hichis probably the mo st co rre ct. Now ,

w he n the distan t signalrise s to danger, it w ill

,in so do ing

,comple te the e le ctric cir

cuit, by placing the spring E in con tact w ith the pie ce o f me talD, w hich is already in co n tact w ith the spring C ; the e lectriccurre n t w ill, during the time the arm is in this po sitio n

, co n

tin n e to flo w from the batte ry through the co ils o f the repeate r,alo ng the lin e w ire , through the co n tact pie ce s at the back o f thearm

,to earth. But the in stan t the arm o f the distan t signalis

depre sse d,or leave s the pe rfe ctly horizo n tal po sitio n

, the co n tactbetw e e n D and C w ill be broke n

, the curren t w ill cease to flo w,

and the repeater w ill re cord the signal as off o r n o t at danger.

To kn o w w he the r the light ofasignal-lamp is burn ing,or n o t, is

as impo rtan t, o r n early so , as to kn o w w he ther the arm o r the

pe cazcles act faithfully or n o t. At n ight time and during fogsall

RAILWAY» SIGNALS . 181

d e pends on the light,and the due actio n o f the smctaele s ; fo r

s ignalat po in ts w here such is kn o w n to exist as adanger-signal, iti s

'

likely to lead to mistake s ; because , in the first place , w he re thereis but o n e light the driver may o versho o t the spo t, and in the n ext

place, w here there are mo re than on e,an existing light may be

taken for that w hich has gon e o ut.

Fig. 5 w ill afford amean s of describing the mode of

ing the actio n o f the light. Regardin g it as ace n tral cro ss-sectio nof that po rtio n employed w ithin the lamp, AA is acircular iro nframe , pre ferably made o f cast-iro n , as be in g le ss susceptible o f

expansio n from heat. B is apie ce of copper to fit A,beate n some

w hat co n cave , and firmly fixed at its circumfe re nce to the frame A .

At its cen tre , o n the re ve rse side to the flame , is astud o r pin C.

I) is an un insulate d lever, cen tred at E, having imparted to it aten de n cy to move do w n w ards by the spring at E. F is an in sulate d cock, w ith adjusting scre w , the object o f w hich is to regulatethe space be tw e e n C and D,

as mav be required , and to comple teth e e lectric circuit w he n D is in co n tact w ith it. To the insulatedco ck F the lin e-w ire is jo in ed, and the framew o rk o f the instru

meat is carried to earth. The diame te r o f the iro n frame A maybe about three inches, and the con tact po rtion should be co vered into prote ct it from dirt. The w ho le may very co nven ie n tly befitte d w ithin the top o f asignal-lamp w ithout in terfering w ith th e

light or draught.

132 ELECTRIC REPEATERS FOR [22nd March

The in te rnal arrangemen t o f the “light re cording in strumen tco n sists ofapair o f co ils w ith an armature , to w hich is attached aw ire rod w ith abell-hammer at its extremity. Ben eath the in strume n t is abe ll-dome , so fixed that any movemen t o f the armatureshall cause it to be struck by the hammer. The lin e-w ire is co n

n ected w ith the co ils through amake-and-break arrangemen t, byw hich mean s, so lo ng as acurren t flow s through the w ire

,aco n

tin uo us ringing o f the hellis kept up. Be tw e e n the po le s of“the

e lectro -magn e t is ape rman e n t magn e t carrying ashie ld w ith thew o rds OUTand IN ,

so adjusted that it shall by gravity exhibit atthe aperture in the face of the in strume n t the w o rd IN

, w hilst theinfluen ce o f the e lectric curre n t shall by reve rsing the po sitio n o f

the indicator bring up the signal OUT. No w ,if the batte ry be

L I G HT

uN S T R u u e n T

{ n o n nat o uC O N T RC Y .

B ELL

FlG . 6

co n n ecte d to the o ther e nd o f the co il commun icating w ith the“ light in strume n t

,and its o ther po le be put to earth

,w e shall

have aco n tin uo us curre n t flo w ing through the co ils o f the in strumen t alo ng the lin e -w ire to the adjusting screw F, and thro ughthe lever D ,

to earth at the signal lamp. This is so w he n the reis n o light burn ing ; but n o w le t alight be applied. The heatw illspe edily expan d the me tal disc B , w hich in expan ding w illcarry upw ards the pin 0

,pre ssing it again st the leve r D

,and

finally carrying it aw ay from the co n tact G. The lin e is the nin te rrupted , and n o curre n t can pass. The bell cease s ringing

, an d

the in dicato r be ing n o lo nger under the influen ce o f the curre n t

falls back to LI

I

GI

r

q

HT

i’ and there remain s so lo ng as the in

flue n ce o f the heat upo n B ke eps up its expan sio n . The action is

therefo re this w hen the light is burn ing the indicator sho w s

“ light in , and the hellis quie t ; w hen the light gro w s dim, o r

go e s out, the e lectric circuit is again comple ted,the indicato r re

co rds light o ut,” and the be ll co n tinue s to ring un til it is re sto red.

To th e fro n t o f the in strumen t is fixed as witch ,{or th e purpo se o f

134 ELECTRIC REPEATERS FOR [22nd March ,

2.— To w hat S ignalshould R ep eaters be applied ?

It is scarce ly n ece ssary to say the ir chief applicatio n must be in

co n n e ctio n w ith the distan t signal. Distan t signals are the farthe stremo ved from the vie w o f the signalman , and are thus mo re apt tobe obscured in fogs and bad w eathe r than tho se n eare r home . At

the same time it is an ope n que stio n w he ther starting signalsand home signals

,w here w o rked aw ay from the signal-box, sho u ld

n o t in asimilar man n er be repeated back to the signal-box. It is

n o doubt asafe prin ciple to co n sider the w o rkin g o f arailw ayunder its mo st adverse circumstan ce s

, and to pro vide for it acco rdingly. Pe rhapsaden se fog is on e o f the w o rst co n ditio n s un de r w hichrailw ay traffic can be w orke d. At such momen ts the impo rtan ceof the due actio n of every signal can n o t be o ve r estimated. The

fact that afogman stands ready to co nfirm the danger signal byde to nato rs,” do e s n o t alter the circumstance s, fo r although , from

the signal itse lf be ing o bscured , it may n o t be so impo rtan t that thesignal arm shall rise fully to dange r, the re is ye t the chan ce o f the

w ire hanging in asheave . Again,w ith regard to the home signal,

it is n o t un usual, especially w ith jun ctio n signals,for them to be

erected o ver the signal-box e n tire ly aw ay from the view o f the

signalman . It is n o t, pe rhaps, pro bable , but it is at the same time

qu ite po ssible , for adisco n n e ctio n to take place be tw e en the rod byw hich the arm is w o rked and the arm itse lf. It w ould doubtless beaw ise pro ce eding if eve n home signals so place d at jun ctio n s w ere

repeated, as w e ll as tho se at agreate r distan ce .

3.—The nature of the indication .

Con siderable diversity o f opin io n exists as to the nature o f the

indicatio n n ecessary to be re co rded . Whe ther the repeate r sho u ldsimply show w hen the signalis at danger w he ther it shou ldshow w he n it is on and w he n it is o ff o r w hether it shouldre co rd the thre e po sitio n s, “danger,

” “cautio n

,

” and clear,” o r

e ven go beyo n d this, and sho w the in termediate po sitio n s.In dealing w ith this po rtio n o f the

.

subject it w ill be w e ll toco n sider w hat is the po in t o f danger. Clearly the po in t of dange ris that w he n asignal w hich is in te nded to be ON ,

and w hich has,

so far as the mean s of w o rking it is co n cern ed be en put ON , do es

n o t stand at danger. It is then the man w orkin g it.regimes tn he

1m .) RAILWAY sre nu s. 135

to ld the signal is no t o n . If asignal do e s n o t stand of w he n it issuppo sed to have be e n pulled o ff

,n o po sitive dange r w ill arise .

Anapproaching train w o uld draw o n to W ithin sight o f the homesignal, and se e ing thisat allclear w ould pro ce ed, the driver probably in dicating to the signalman as he passed thathis distan t signalw as n o t of .

” With such in dicatio ns and w ith the w histle o f eachsucce e ding train , the signalman w ould spe edily se e to the adjustmen t o f the w ire . Re peate rs, to aco nsiderable n umbe r, have be e nw o rked o n this prin ciple fo r some time o n the Lo ndo n and So uthWestern , the Lancashire and Yo rkshire , and o ther lin es

,w itho ut

incon ve n ie nce . Such asystem re quire s but o n e w ire,and the

battery pow er is o n ly in operatio n during such time as the signal

To show w he n the signal is ON and OFF, or to sho w w hen it isat danger ,

” “cautio n ,” and“clear,

”require s tw o w ires ; an appli

cah'

o n o f the duplex mode o f w o rking w ith tw o batter ie s and amo dified arrangeme n t o f the instrum e n t ; o r placing the batte rie sat the signal-po st

,an o bjectio nable course , as they w o uld certain ly

fre eze during the co ld w eather,and the e lectrical signal w o uld thusbe emn e in operative .

A me thod has be e n pre poaed by Mr. W. H. Preece w hich w illo ve rcome this, be applicable to the instrumen ts in use , and stillo nly co nsume the batte ry po w e r w he n the signal do e s n o t stand atits lo w est po int, w he ther that be cautio n o r allclear.

”Such

ame thod w o uld require asomew hat mo re complicate d arrangemen tat the signal-po st, and w o uld co nseque n tly be atten ded w ithsome slight in crease in first cost, but in no w ay such as to operateagainst its employment if de emed necessary .

4 .— The P oint of Con n ection w ith the Signal.

This is an impo rtan t questio n . It is the arm w hich co nstitute s

the signal by day and the“spe ctacle s by n ight. To the se parts

them sho uld the co nn e ctio n be made . It is be lie ved that hithe rton o co nn e ctio n w hatever has be e n attempte d w ith the spe ctacles

,

”

the attachmen t be ing made e ithe r to the arm ,o r to some part o f the

ro d, o r the lever w o rking the arm . A mome n t’

s re fle ctio n w ill,ho w eve r, show how desirable it is that the co nn e ctio n sho uld bew ith bo th, in such aman n er that the actio n of th e on e M ‘

n e

136 ELECTRIC surnam e s FOR [22nd March ,

by means o f the same w ire , an d w ith mere ly the additio nalexpe n seo fan o ther pair o f springs.

It may be argued that there can be n o reaso n to doubt the dueactio n of the arm if the lever has its due actio n , but the re is thechan ce , although perhaps aremo te o n e of abo lt giving w ay , o r

the arm be coming lo o se o n its so cket, and it is desirable to pro videagain st such chance s happe n ing at in oppo rtun e momen ts. It is

n o t unkn o w n to the author that there are signals w hich , from the irhe ight and co n structio n , it w ould be difficult to so fit

,but the se are

the ve ry signals w hich should be so fitted, because it may be fairlyassume d they are from tho se very cause s le ss like ly to me e t w iththat care ful in spectio n from the me chan ical bran ch o f the serviceso n e ce ssary to ke ep them in prope r repair, an d so avo id failure .

Disc signals should in alike man n er, w here po ssible , be fitted

at the iro n shaft to w hich the disc is fixed, and the e le ctrical co nn ectio n w ith the se should be made as w ith the semapho re

, thro ughthe fittings applied to the shaft carrying the lamp fo r the n ightsignals.The co n ne ction for the “ light repeater w ill of course in allcase s be w ith the lamp.

5 . The Form of Instrumen t, or Indication .

As w ith blo ck in strumen ts, so w ith e le ctric repeate rs,various

means are employed fo r indicating the con ditio n o f the signal.With the in strume n t adopte d byMr. Pre e ce , amin iature semapho reis, as arule , used, but o ther forms o f min iature s of the signals to be

repeated have be en , and still are,employed. With Mr. Warw ick

an indicator o r po in te r has be en made use of,w hilst Mr. Spegn o

letti uses asmall shie ld w ith the w o rds ON and OFF, w hich arebro ught up to an aperture in the face of the in strume n t in acco rdan ce w ith the mo vemen t of the arm. For the light re cord, asome

w hat similar arrangement is employed by each, viz a shie ld

carrying the w ords OUT and IN,o r an indicato r po in ting to the

same,as the case may be , w hilst w ith the first-named indicatio n a

be ll is se t ringing,and con tinue s to ring un til the light is resto red,o r

that portio n o f the apparatus is put out o f circu it by the use of asmall sw itch, fitted to the in strume n t w ith that obje ct.The re is pro bably n o great cho ice betw e e n the fo rms mentio n ed,

for assuming e very signalman is sufficien tly educated to read the

ELECTRIC REPEATRRS FOR

during frosty w eathe r,a

if the springs are stro ng e n o ugh, remo ve it. S tillth e em

o f astro ng key, w ith ago od rubbing actio n , might be

w ith co nve n ience in fixingand fo r repair.

In co nclusion , w ith e very confide nce in the efi cie n cy ando f the se in struments to pe rfo rm the w o rk require d o f them

,

me n sho uld be in structed, w he re ve r a re peate r

to s uppo se , because it do es no tact, that the ”pasta

ou the reverse , to conclude that it is his signalw hich is m ac. as

take steps at once to assure himself of the contrary.

Mr. LANGDON (supplementalto his paper) said Mr .

Iam glad to have this oppo rtun ity of bringing unde r the

tion of

o n ly tocan be

the pro te ctio n of railw ay trafi c it is equally ne cessary some w e

should be obtain ed in o rder to show that they w o rk as thewas

intended to w ork. It may be advanced as an argum e n t again!

the employmen t o f e lectric repeate r signals that the re are ml}railways o n w hich they have n eve r bee n used

,the traffic o n whid

has be en co nducted hitherto w ith perfect safe ty, and in suchamat

n er as to sho w that there is no w an t w hate ver of repe titio n to tl!

signal; but the same might have be en argued w ith regard to ti!

signals recen tly used o n the Great No rthern line at Abbo ts Rip“!had n o t the trains there follo w ed in clo se proximity o n e o n the other.

Had there be en agreate r in te rvalbe tw e en them, in allprobabilitythe acciden t w ould n o t have arise n ; and the same might be urged

in o the r w ays. Un less signals fo r the go vernmen t o f railw ay tn flitcan be made infallible , arepe tition o f some kind is certainly new

sary in the pre se n t state o f in creased railway traffic. But it mayl!

furthe r argued that e lectric repeate rs have already establishe d themse lves. Such , n o doubt, 1s the fact w ith regard to some o four railwaysmt eve n in tho se case s it is o n ly the fact to avery partialextent

ule ctric repeaters have be e n employed o n ly 1n isolated places,aunder specialco nditio n s. For in stance— w here the Signalsan

1876. RAILWAY SIGNALS. 189

m y fimn the signalman’s vie w en tire ly, o r perhaps at some

importan t jun ctio n w he re some mishap may have occurred, o r

where some thing may have arise n to shake the co nfide n ce o f the

railway manage r in the signals at that po in t.In the paper w hich I have read I have no t attempted to deal indetail w ith the several fo rms o f in strume n ts that are used fo r this

purpose ; n eithe r have I sought to explain the mean s o fapplyingthem to the signals w hich are required to be re peate d ; fo r I havethought that an Opportun ity such as this w ould be embraced by allthose in tere sted in the que stio n to discuss these po in ts , and to bringbefore the Socie ty such appliancesas w e re thought fit fo r the o ccasion ; and that it w ould be be tter to leave to those in te reste d inthem the explanation o f the ir arrangemen t

,e lectrical and o the r

Wise . I am so rry I have be e n so un fo rtunate w ith regard tothe instrume n ts, w hich o ught to have arrived this afte rn o o n , asotherw ise I sho uld have be en able to have give n amore practicalillustratio n o f the actio n o f the signals, and abe tte r de scriptio n ,perhaps, o f the e lectrical fo rmatio n o f the instrume n t. I do n ot

dink amore oppo rtune o ccasio n could have o ccurred fo r the disenssio n o f this que stio n than the pre se n t. The railw ay mind hasbeen bro ught to lo o k upo n it in avery fo rcible man n e r. We , o ur

selves, are he re un de r the pre side n cy o f o n e w ho has spe n t n o

small po rtio n o f his life in the applicatio n o f electricitv to railw ayWarking ; and, n o do ubt

,w hatever de cisio n it may lead to , the

result w ill be lo o ked upo n by railw ay compan ies as having be enflirly fo ught out and dealt w ith by railway me n .

THE PRESIDENT : You have heard this pape r read. It must

have reminded some o f yo u o f aco uple t in Home r’

s Iliad, thus

A w ise physician skilbd o ur w o unds to heal,Inmo re than armies in th e commo n-w eal.

Imean , that e lectricity is n o w so pre ssed in to the se rvice o f railways

, that n o t o n ly is safe ty mainly de pe nde n t upo n it ; but it

keeps them in aw holesome state o f health. Train s, fo r instan ce ,

are ke pt apart by its use , but it heals the w o unds and accide n ts o f

their system ; if acasualty occurs,the re spo n sibility fo r sofie n ing

the blo w re sts w ith tho se w ho have the charge o f the e lectrical ap

140 ELECTRIC REPEATERS FOR [22ndMarch ,

tio n o f the guard, o r if the guard fails in getting the atte n tio n o f

the e ngin e-driver. If the distan t signals fail to obey the le ve rs o fthe signalman , e lectricity is re spo nsible to te ll the tale . In fact,the mo re you lo ok into railw ays the mo re you w ill se e and co n

tin n e to se e that w ith us railw ay telegraph engin e e rs alargew e ight o f re spo n sibility re sts. Whateve r go es w ro ng

,w e are

called in to requisitio n . Shou ld an engin e break dow n,o r de fects

o f any kind o ccur on the railw ay itse lf, and should e le ctricity

fail to reach the e lectro-magn e ts and galvan ome ters, and do its

full duty, the e lectric te legraph departme n t has to bear the burdeno f failure . But

, also , w hat avery great frie n d e le ctricity is to thetrave lling public ! Of this I , myse lf, can pe rso nally bear w itn ess.

I have n ow to call upo n gen tleme n prese n t, w ho , I have n o doubt,

w ill be glad to speak upo n this attractive and very in te re stingsubje ct.Mr. HIGGINS : I be lieve it is be tte r to have tw o w ire s to w ork

the sig nal mechan ically in stead o f o n e w ire,as w e ll as the te le

graph . This w ould have the advan tage o f requiring less strain tolift the danger signal, and w ould also indicate w hen the w ire w as

broke n ; it could o n ly go w ro ng at any time to the exten t o f

putting the dange r signal at cautio n .

”The plan w hich I re com

me nd w o uld be to have adrum in co n n e ctio n w ith the semaphorearms, o r the rods w hich lift them ,

and aco rrespo nding drum atthe signal-box. A w ire , e n dle ss o r n o t

,sho uld then be faste n e d

w ith staples to the drums. Any moveme n ts o f this drum at thesignal-box w ill pro duce acorre spo nding mo vemen t o f the drum atthe signal -po st. In case the W ire break the signalman w ould se e bythat w ire n o t be ing pulled o ut that the signal had n o t re spo n de dto his w ish. Whe n aw ire breaks be tw e e n the time o f the signalbe ing put o n and be ing re quire d to be put o ff, that could n o t affe ctthe train s, be cause the signal o n ly w aits the signalman ’

s pleasureto change , and as so o n as he w ishe s to change if the w ire isbroke n he w o uld discover that by the broke n w ire n o t actin g .

Sn o w co uld n o taffect the arm if w o rke d in this man n e r,be cause

in the o rdinary arrangemen t the semapho re arm is pulle d up bythe co un te rpo ise w e ight, and the co un terpo ise is lifted by pulling a.w ire . In this case the re is n o co un terpo ise to mo ve , and the w ireo n that accoun t w o uld be alittle lighter than the o ther.

Mr. SACH I fe elperso nally much obliged to “it Xm gdon fo r

142 ELECTRIC REPEATERS FOR [22ndMarch ,

Mr. E. T. ROLLS : I have de rived much pleasure from Mr.

Langdo n ’s paper, se e ing that the subje ct is o f so much importan ce

in railw ay w o rking . I quite e ndo rse Mr. Langdo n ’

s remarksupo n the varying ten sio n o f the signal w ire , and can go e venfurther, for I kn o w it to be afact that upo n aday of in term itte n tsun shin e the length of the w ire varie s w ith the passing clo uds.

Some experie n ce in the main te nance o f repeaters has co n vin cedme that fo r various reaso n s con tacts are best e n cased an d pro te cte dfrom the w eathe r.

First, be cause in fro sty w eathe r, just w hen fogs are mo st like lyto make repeate rs of vital n e ce ssity

,an expo se d brass plate fre

quen tly acquire s an insulating en ve lope of ice , and I do n o t fin d

that springs flexible en ough to be safe from breakage w ill scrapethe ir w ay through this glacial en ve lope , and then signalme n are

aptItozge t in to the way o f saying, Oh, it’s the fro st.

Se co ndly, by expo sure to mo isture chemical and sometimes

e lectro lytic actio n w ill frequen tly coat the expo se d plate s w ith saltso f copper from the brass.

As to the nature o f the indicatio n I am o f opin io n that therepeater should certain ly sho w the tw o po sitio ns of “o ff and “o n .

”

By making the curre n t actuate bo th signals, ado uble check is

o btain ed ; the w o rking batte ry may be thereby mo re rapidly co n

sumed, but this has n o t be e n fo un d o bje ctio nable in some blo cksystems.

Furthe r,such aplan w ould be more satisfacto ry to mo st o f

the me n , w ho some times complain that in regulating the w ire tosuit the o n

”repeater signal they have n o thing to check them

again st overdo ing it and making the w ire to o slack to ge t it o ff.To o bviate the expo sed co n tacts

,and register bo th po sitio n s o f

the arm ,using o n ly o n e w ire , I w ould place w o rking upo n the

same axis as the arm and w e ll case d a4-w ay sw itch,w hich w o uld

sho w the signal to be o n o r o ff,as the case may be .

The batte ry must be kept by the signal-po st,and so far from

be ing adisadvan tage I co n side r this again ; w ith a sto ut ke n n e lcove red w ith ro ofing-fe lt, an exce lle n t n o n -co n ducto r o f heat

, fro st

n e ed n o t be feared. I have had batteries expo sed unde r such co nditio n s through the last tw o seve re w in ters, but n o failure o ccurred.

At the w orst ahan d-lamp could be introduced to w arm the littlebatte ry but, as is some times don e in the signal-box batte ry cup

RAILWAY SIGNALS . 148

board— the re , w ith mo re reaso n,thre e sides be ing usually o nly

pro tected from the air by thin matchboardin g some time s n o t devo ido f o pen chin ks . The advan tage I claim is that the lineman must

go to the signal itse lf to atte nd to the batte ry,and then he w ill

pro bably examin e the co n tacts. But w ith the batte ry in the signalbox and the co n tacts ‘

o n asignalpe rhaps three-quarters o f amile

aw ay,alin eman in dirty w eathe r is apt to shirk the w o rk o f

making ajourn ey to the signal and back.

As to the light repeate r. I have had w orking fo r some time anapparatus co n sisting o f tw o comman d plate s arranged thus

The M elof the top-plate is o n the upper side

,the brass at the

bottom. The lo w er plate has the ste e l un dern eath ; they are bothrive tte d to ge ther at on e e nd a

,and at the o ther e nd 6

, one plate isfixed to the side o f the lamps. S is aco n tact-scre w insulate d from

Un der the influen ce o f heat the plate s curve in oppo site direction s,and the lo w er compo site plate also tips the top o n e upwards, addingthis mo tio n to that o btain ed by the curvature by heat, and the tw o

e thing like this po sitio n

Thus w itho ut the assistan ce o f any multiplying leve r o r o therdevice o f the kind avery w ide mo tio n is o btain ed direct from the

Source , so affo rding great n ice ty o f adjustme n t by the in sulate dcontact-screw ,

and ago od rubbing-co n tact .

Tw o o f these repeate rs have be e n at w o rk for aco nside rable timeWithout failure ; as far as I have any kn o w ledge , fo r mo re than tw oYears w itho ut ahitch ; o n e w as attached to alamp w ith avarying

when it sunk to o lo w , as it some times did in the smallh ours .

144 ELECTRIC REPEATERS EOE [22ndMarch,

Allthese light-repeaters require aw ire fo r the ir separate use,

but it has just o ccurred to me that by placing in circuit atube of

se le n ium in front o f lamps sho w ing w hite and red and having alsoin circuit abalan ce d resistance

,the disturban ce o f this balan ce by

the varying actio n upo n the se le n ium o f the actin ic w hite rays andn o n -actin ic red w o uld enable asingle w ire to re co rd by daythe po sitio n o f the arm,

the spe ctacle by n ight,and the co n ditio n

o f the light.I have placed o n e o f the light-repeate rs o n the table , and shall be

happy afte r the discussio n to explain its w o rking mo re fully.

Mr. A. J. S. ADAMS : I have se en o n some railw ays the repeaterde scribed by Mr. Langdo n

,in w hich the bar o r rod mo ving the

arm has aplate attached to it, the plate passing up o r dow n betw eentw o in sulated springs. It struck me as be ing po ssible fo r the co r

recting-bo lt to slip and allo w the bar to slide W itho ut mo ving the

arm ; therefore I think the proper place fo r the co n tact is be tw e enthe arm itse lf and ame tal co n tact. I have w atched some o f the serepeate rs o n the Great Eastern Railw ay fo r thre e w in ters,and theyhave alw ays pre sen ted clean co n tact-surface s.

Mr. C . E. SPAGNOLETTI With regard to signal-repeate rs,w hich Mr. Langdo n ’

s useful paper has bro ught befo re us,the first

I tried w as o n the Me tropo litan Railw ay,in 1863. Whe n that

lin e w as first ope n ed it w as required to w ork signals from o n e

statio n to the n ext statio n in the rear ; and as the distan ce w as

great it be came aque stio n w he the r the signals should n o t be

repeated. This be ing de cided to be do n e,I put up seve ral

repeate rs and they w o rked w e ll,but it w as fo un d the distan ce w as

to o great fo r the signals to w o rk satisfacto rily,and co n seque n tly

they,w ith the repeate rs

,w e re remo ved and the lin e w as w o rked

o n my blo ck system e n tire ly. Some have late ly be e n fixed o n theGreat We stern Railw ay o n the prin ciple o f w hich I have amode lhere . This syste m sho w s the po sitio n o f the arm

,w hen it is o n

,

w he n it is off, and w he n it is w ro ng,i. e . , ado ubtful po sitio n

be tw e e n ace rtain and unmistakeable signal, be cause it is po ssiblew here yo u have o n ly o n e co n tact w hich mo st e le ctrician s use

,if the

arm is just be lo w the co n tact-po in t the indicato r w ould sho w the

signal w as do w n , w he reas the signal m ight be mistaken by thedrive r fo r be ing up, and it w ould be the cause o f de lay as w e ll asaback the train . The system is excessively simple w hich isamost

146 ELECTRIC REPEATERS FOR [22nd March ,

and clear signal, and ho w ever much mo re heat you may ge t, andthe expan de r in crease 0 11 its expan sio n

,co n tact shall be kept up

be tw e e n this min imum po in t and the maximum po in t of expan sio n ,n o matte r ho w it varie s be tw e e n the se tw o po in ts ; but dire ctly itco n tracts sufficie n tly to ge t be low the min imum po in t the n co n tact

is broke n and the lamp is sho w n as o ut,w hich fo r practical p

po se s it may con side red to be . The in dicato r I use is o n e o f my

ordinary disc in strume n ts ; o n e disc re co rding the moveme n t o f thesignal arm, w he the r o ff

,o n

,o r w ro ng, the o the r disc reco rding the

burn ing of the lamp, sho w ing lamp in o r o ut. In co nn e ctio nw ith the light indicato r there is a sw itch ; the man lights the

lamp,and w hen the disc sho w s light in

,

” he then turn s the

sw itch handle to hello n,and brings the be llin circuit. If th e

lamp go e s o ut the co n tact made w ith the disc is broke n , and it fallsto “lamp o ut

,and the be llat o nce comme n ce s to ring

, callin g theatte n tio n o f the man to the fact at o n ce ; if the sw itch is turn e d o ffthe be llstops ringing

,but the disc still sho w s “ lamp out un til

the lamp is re lit. The be ll affo rds an exce lle n t mean s o f te sting thein strumen t at any time during the day. Yo u have o n ly to turnthe sw itch-han dle to be llo n to se e that the in strumen tand batte ryis in go od o rder. This is an e co n omical system to use

,and e co n omy

is an e ce ssary thing,because if the se repeate rs are very large ly

used,w hich n o do ubt they w ill be , the ir co st w ill form aco n sider

able item . Mr. Higgin s has called atte n tio n to n ight to the do ublew ire system : that is avery go od system

,be ing o n e o f the first

,

and w as in troduced by Mr. Brun e l o n the Great We stern Railw ay ; in fact I be lieve it w as his o w n sig nal

,and w as w o rke d

w ith ado uble w ire , but altho ugh the signal may go to danger, ye tif the w ire breaks yo u have n o in dicatio n o f the fact that the w irehas become broke n in the signal-box un le ss the lever w as moved.

The PRESIDENT the n an n oun ced that, as the hour fo r clo sin g hadarrived, the discussio n o n this pape r w o uld be adjo urn ed un til then ext me e ting.

RAILWAY SIGNALS. 147

The Forty-se ve n th Ordinary Ge n e ralMe etin g w as he ld o n Wedn e s

day , the 12th April, 1876, Mr. 0. V . WALKER ,

Preside n t,in the Chair.

The pre liminary busin ess o f the me e ting having bee n transacte d,The PRESI DENT said : At the last me e tin g Mr. Langdo n read

apape r on“Ele ctric Repeate rs

,

”the discusio n upo n w hich w as

commenced . It n o w devo lves upo n Mr. Langdo n to reply,un le ss

,

in de ed,o ther membe rs may desire to make further remarks upo n

the questio n o r upo n the instrume nts pro duced . In that case w e

shall be pleased to hear such remarks.

Mr. F. RUDALL : I be lieve, Sir, visito rs are allow ed to take part

in the discussio ns ? If so I w o uld say, afte r abo ut te n years’ex

perience of e lectric distant signal indicators o r repeate rs o n the

Lo n don . Chatham and Do ver Railw ay , that the co nclusio n at

First, that the source o f the ele ctric curre n t shall be at the distan tsignal itself; the latter in fact may be

'

regarded as an automaticblo ck signal station , and it appears to me that n o o n e w ould thinko f se nding the curre n t from o n e statio n fo r the signm at the

distan t statio n to use in replying. The source of the curren t shouldbe at the signalling statio n itse lf. Again you w an t to re tain aclearspace be tw ee n the distan t signal and the box, and the re fo re it isdesirable that the so urce o f po w e r should be at the signal itse lf. I

may add that w e have our batteries boxed in to pro tect them from

The se co nd po in t is, that the po sitio n o f the semaphore armw hen at danger shallbe sho w n by aco nstan t po sitive curre n t,

w hich moves asuspe nded n e edle to po in t to the w ords signalo n ,

” and the po sitio n o f the arm w hen at safe ty shallbe show n byaco nstan t negative curren t, w hich reve rse s the n e edle , so as to

make it po in t to the w o rds “signal o ff in fact, ours is ao ne w ireL 2

148 ELECTRIC REPEATERS FOR [12th April,

system ,w o rked by mean s o f a reve rsed curre n t, po sitive fo r

danger and n egative f or safe ty.

The third po in t is,that w he n the semapho re arm e ithe r fails to

reach abso lute dange r, o r to be lo w ered to abso lute safe ty, thecurre n t is broke n and the n e edle assume s aperpe ndicular po sitio n .

The inge n io us ideao f employing gravity to indicate o n e o f the

po sitio n s w as aban do n ed, be cause w hile the semapho re arm itse lfmight failto act properly the in dicato r w o uld o n ly sho w this as too n e o f the tw o po sitio n s ; and altho ugh the te legraph w ire mightbe broken and the e le ctric circuit de stroyed, the in dicato r in the

signal-box w o uld still give its gravity reading. The abo ve is asummary o f the me thod w e have fo un d it de sirable to ado pt.Our Engin e e r is mo st exacting in having a co n stan t curre n t

alw ays at w o rk . The re is, o f co urse , aco n side rable expen diture

o f batte ry-po w e r,but then the signalman kn o w s po sitive ly that

w hile the curre n t is w o rking the signal itself must be po in tinge ither to dange r ”

o r to safe ty,

” as the case may be . We

have had the se in strume n ts e ight o r te n years in w o rk,and

w e find they give very go o d indicatio n s. The o n ly difficultyhas be en w he re the rod has n o t acted properly, and I quite thinkthe curre n t sho uld be sen t

,as in Mr. Spagn ole tti

’s mo de l

,by

mean s o f the arm itse lf in stead o f by the signal red,as is do n e in

the case o f Mr. Sach’s inge n io us co n tact apparatus. That is all

the light I can thro w upo n the matte r.

Mr. LANGDON : I shall be glad, if n o t tho ught tre spassing, torede em my pledge w ith re fe ren ce to the e xhibitio n o f the in stru

me n ts o n the table . I un fo rtunate ly o n the last o ccasio n m issedo btain ing the requisite apparatus to illustrate my pape r. Thatapparatus is n o w he re . (Mr. Langdo n here de scribe d the apparatus w hich had be e n placed o n the table , and w hich co n siste d o f

'

mo de l distan t signals, repeate rs o f. vario us fo rms,and expan sio n

pie ce s,the applicatio n o f w hich w as practically illustrated. )

In addre ssing myse lf to this subje ct I have e ndeavo ured to co n

fin e my remarks as much as po ssible to the po in ts w hich are mo st:

impo rtan t to o btain an e fficie n t repe titio n o f distan t an d o ther'

gnals w h ich re qu ire to be repeated. Of co urse the re are manyrm ode s o f e ffe cting this ; but if w e in troduce an e rro n e o us system,

150 ELECTRIC REPEATERS FOR [12th April,

fo rtunate ly n o ticed the state o f the signal. In this case the signalw as w ithin 10 o r 12 yards o f the man w o rking it, and ye t he w as

unable to te ll w he ther it w as w o rking properly o r n o t. I w ou ldn ext say that distan t signals sho uld be repeated in allcase s w herethe blo ck is in use or the trafi c is heavy. Whereve r the block is inuse train s are run at rapid rate s and at short in tervals. Whe reverthis is the case there is to o little margin fo r failure ; the failure o f

a signal may lead to fatal co n sequen ce s. If it is n ece ssary todivide lin e s o f railw ay in to blo ck se ctio n s to ke ep the train s apart,it is n ece ssary that the signals should act w ith perfect accuracy,because if they do n o t the o bje ct o f the blo ck is e n tire ly lo st : thedistan t signalis the key of every section .

With regard to the nature o f the indicatio n some varie ty o f

opin io n exists. Some require o n ly o n e indicatio n and o thersrequire thre e . Mr. Rudall prefe rs to have thre e signals, and Mr.

Sach also , but in the paper I have give n reaso n s fo r requ iring o n lyo n e signal. I regard the que stio n as o n e w hich sho uld be discussed

,

more particularly by railw ay me n,w ho kn ow the ir o w n re qu ire

men ts be st. AllI de sire to po in t o ut is,that w ith the existing

systems o f repeaters, w here tw o o r thre e indicatio n s are required,

tw o w ire s must be used o r the batte ry must be placed at the signalpo st. Mr . Rudall says he place s h is batte ry at the po st. I w o uldask him w hether he has found any in co n ve n ie n ce arising from co ldw eather ? Mr. Sach also stated he place s his batte ry at the signalpo st. I have myse lf had some experie n ce in using batte rie s placedout o f do o rs . VVhen— some years ago — blo ck signals w e re be ingput up o n the South We ste rn Railw ay

,mean s w ere wan ting fo r

placing the batte rie s in some o f the signal boxe s, and they w e re

co n seque n tly e n clo sed in case s lin ed w ith straw . Ye t the fro st

attacked the batte rie s. I fe e l satisfied batte rie s placed in suchpo sitio n s must

, during aseve re w in te r,become co ngeale d and

re n de re d in ope rative . I there fo re stillstro ngly advo cate placingthe batterie s in the signal-box in stead o fat the po st.I have in the pape r referred to aplan w hich Mr . Pre ece has

de vised fo r w o rking arepeate r from the distan t signal by mean s o fo n e w ire , w ith one battery placed in the signal-bow , and w hich shall

give three or mo re indication s, as may be required . I am sorry

RAILWAY SIGNALS. 15 1

Mr. Preece is n o t here o r has n o t commission ed some o n e to explainto the me e ting the mean s by w hich he pro po se s to e ffect this, butitisperfe ctly practicable , and it is o n e o f the safest mean s I kn o wof obtain ing the se in dicatio n s atalo w co st. It is eviden t, if yo uuse the battery at the signal-po st, the battery must be alw ays

With regard to the conn e ctio n at the signal-po st, w e have hadno referen ce to the suggestio n thro w n o ut that it should also beextended to the spectacles w hich fo rm the signal by n ight. It is a

very impo rtan t que stion , and I thinkallrailw ay te legraph engin e e rswould do w e ll to give it con sideratio n , because there is equally asmuch danger attending the w o rking o f the traffic at n ight as inthe

.

daytime , and therefore if it is n ece ssary to repeat the actio nof the arm it is e qually n ece ssary to repeat the actio n o f the

spectacle s . As to e le ctrical co n structio n , the ge n eral impre ssio nseems to be that the co n tact arrangeme n t at the back o f the arm

is the be st, but that it should be covered in or pro tecte d from the

weathe r. Mr. Go ldsto n e , o f the So uth Weste rn Railw ay,has be e n

kind e n o ugh to se n d me an arrangeme n t w hich he has employe dfor this purpo se , and he in te nds to alte r allhis co n tact arran gemen ts to the same plan . It is a ve ry n eat co n trivance and isw orthy o f in spectio n .

I fe e l that I cann o t co n clude w ithout refe rring to the remarkswhich fe ll from the Preside n t w ith re spect to the applicatio n o f

electricity to railw ay w o rking o n the o ccasio n of the last me eting .

He the n stated it is usually o n ly w he n every o ther e ffo rt has be e ntried that the te legraph bran ch is had re co urse to and ge n erallywith succe ss. This I can qu ite endorse

,and I think any perso n

who has akn o w ledge of railw ay w o rking can readily understandit. The te legraph bran ch o f o ur railway system has n o t rece ive dthat confiden ce w hich it me rits. This is perhaps due to o n e o r tw o

causes. In the first place it is probably o w ing to the fact thatrailway manage rs kn ow but little about e lectricity , and co n se

quently have n o t so much re lian ce o n it as upo n mechan icalapplian ce s, and w hich are mo re eviden t to the eye .

The large fie ld open to the e co n omical andadvan tage ous employment of e le ctricity in rai lw ay w o rking must ho w ever ere lo ng be

152 ELECTRIC REPEATERS FOR [12th April

bro ught fo rcibly befo re eve ry railw aymanagemen t, and there can be

n o do ubt that the day is fast approaching w he n the te legraphbranch o f allo ur large railw ay systems w ill ho ld apo sitio n se co ndto n o n e in the service .

The PRESIDENT : I think w e are much indebted to the autho r o fthis pape r for bringing befo re the So cie ty asubject o f this ve ryin te re sting kind ; and I am sure that befo re w e pass o n to the n ext

pape r you w ill agre e w ith me,and gladly

,to give him y o ur thanks.

The subject w hich has come be fore this So cie ty w ill go o ut o f thisro om in to the railw ay w o rld

,and w ill do ubtle ssattract the atten tio n

o f railw ay compan ies to w ards this use ful applicatio n o f e le ctricitymore fo rcibly than it has hitherto do n e . The te legraph engin e e rsattached to the vario us railw ays are quite able to comply w ith allreaso nable in structio n s that may be given to them

,w ith the v ie w

o f pro viding any e lectrical arrangeme n ts that may be required ;but I do n o t go quite so far as Mr. Langdo n in thinking thate lectricity sho uld be made to o re spo n sible fo r some things. Thereare few things in reaso n beyo n d o ur grasp

,beyo n d o ur po w er.

But w e must n o t to o readily tran sfe r to o urse lve s and acce pt .

the

re spon sibility o f care le ssn e ss o n the part o f o the r pe o ple . Thisin tro ductio n o f e le ctric repeate rs to the distan t signals o f the

railw ay, the So uth Easte rn , to w hich I am attached,is ave ry old

que stio n w ith us. lVe had in structio n s some years ago to applye le ctricity to distan t signals. W e applied it ; and are co n tin u ingw e ek by w e ek

,and as fast as w e can , to exte nd the applicatio n in

dive rs dire ctio n s. Our impre ssio n is, that e le ctric repeaters ShallSho w (1) w he n asignal is up an d (2) w he n it is do w n , and also(3) w he n the gre e n and red spe ctacle s each in part are visible the

signal be ing do ubtful , that is, in afalse po sitio n . I belie ve thatw as the p o sitio n o f the signals at Abbo ts R ipto n o n the n ight o fthe co llisio n . I w ould sav further

,t hat the railw ay te legraph

e ngin e e rs are ready to me e t requireme n ts put be fo re them fo r stillmo re complicated applicatio n s o f e lectricity . It is o n ly to be ho pedthey w ill n o t be asked to be to o much re spo n sible . R eally o n e

some time s thinks w e are almo st to be re spo n sible fo r e ve rythinge lse that fails, e le ctricity 0 11 arailw ay be ing in practice the o n e

be ing assumed to be in fallible . If Mr. Langdo n and the o the r

154 WORK-VALUE or ELECTRO-MAGNETS [12th April,

is o n e w ay in w hich I have applied them : in the Dabo scy form

o f e le ctric lamps,an e le ctro -magn e t is employed in co n n e ctio n w ith

the clo ck-w o rk,w hich regulate s the carbon po in t. With asmall

battery I fo und the o rdinary fo rms o f e le ctro -magn ets had n o t

sufficien t pow er over the ke epe r to obtain the n e ce ssary in crease .

I enclosed the electro-magn e t in an iron tube , conn ecting it at the

base w ith the cen tre tube or bar, and surmoun ted the o uter tubew ith an iro n flange . This enabled the po les to act w ith co n siderablepow er o n the ke eper.

”The w o rds in italics con tain the fun dame n tal

prin ciple s o n w hich these magn e ts are co n structe d. In fact, an

o rdinary straight e lectro -magn e t becomesaho rse-sho e o r U—magn e t,

and w ith its po lar extremities mo re than tw ice as n ear to eacho ther as they can be by any o rdinary arrangemen t, and the

armature practically o n e-half sho rte r. Thisis se en at aglan ce o n fig. 1

,w here aa’

is

the iro n co re ; the full lin e , b b’

,ase ctio n o f

the iro n cylinder and o f the iro n disc o r bar

that jo in s it to the back end o f the co re aa’

;

the do tted lin e 0 c’

is asimilar sectio n on

the oppo site side o f the cylin der, an d so o n

Fig. 1 . allroun d so that,if the fro n t e nd N o f the

co re acquire s n orth po larity under the actio n o f the curre n t, the

back e nd S o f the co re w ould have acquired so uth po larity, but

w hich w ill n o w be sho w n at the fro n t e nds S’ S” o f the cylin der.

But the curre n t at the same time w o uld be inducing south po larityat the fro n t e nds S’

S”o f the cylinder, w hich mutatis mutandis

w o uld make the fro n t e nd N o f the core stillmore full o f n o rth

po larity. This appears to be the rationale o f the actio n o f thesemagn e ts.

An e le ctro -magn e t o f this kind w as long sin ce figured and thusde scribed by Mr. D. Davis, o f Bo sto n , U.S

In figs. 2 and 3 are repre se n te d,at aa

’

,tw o do uble cylin ders

o f iro n , e nclo sing aco il. A sectio nal view o f o n e o f them is givenseparate ly at A (fig. It co n tain s acavity in the fo rm o f a

ho llo w cylinder, adapted to re ce ive o n e -half o f the co il se e n at 0(fig. the remain ing half passing in to the o the r cylin der w henthey are fitted toge ther. A lo ngitudinal open ing o n o n e side of

ENCLOSED IN IRON. 155

the cylinders allo w s the w ires of the co il to pass out. In thisarrangemen t the cylinders adhere w ith great fo rce w he n in co n tact ;

but as so on as the curren t ceases the ir magn e tism in stan tly disappears,and the adhe sio n do es n o t co n tin ue as w ith the semicircles.

Fig. 3. Fig. 4.

When one o f the cylinders is passed o ver the co il, the part exte rio rto the co il exhibits n o se n sible po larity .

”

Thearrangemen t befo re us diffe rs from this in that in the o n e case,

seeing that n o mo tion is required from the armature , the latter insize, w e ight, and arrangemen t is equalw ithandacounterpart o f theenclosing cylin der ; but in the o the r

,the case befo re us

,w here

motion is required, and n o t mere adhe sio n and lifting po w e r,the

section be tw e en case and armature is n o t midw ay, but at o n e end,

Manualof Magn etism, Second edition , p. 171, fig. 111. Boston , U.S . 1848.

156 WORK-VALUE o r ELECTRo -MAGNETS [12th April,

flush in fact w ith t he acting po le o f the co re o f the e le ctro -lnagn e t,w hich ill this in stan ce is expo sed

,and fre e to attract am o veable

armature , that is adjusted, w he n at re st,to be re tain ed by a

spring at agive n w o rking distan ce from the co re,and pro te cted

by banking-pin s from coming in to actual co n tact w ith the co re ,

w he n at w o rk .

Ill text-bo oks that are acce ssible to me w hile w riting,I have

n o t found any de scriptio n n o r any men tio n made o f e lectro -magn e ts o f this co n structio n . On the o ther hand , I find the fo llo w in gpassage in Co un t de Me n e el

’s bo ok Un n oyau de fer e nve lo ppé

par un e hélice volta'

ique s’aimen te én ergiqueme n t ; alors qu

’un

cylin dre de fe r e nve loppan t ce tte meme hélice n o s’aime n te pas de

In the system w ith w hich I am mo st familiar,fo r spacing train s

to avo id o n e overtaking an o ther, and for o the r kindred purpo se sfo r increasing the comfo rt o f

,and e n suring safe ty to

,Railw ay

trave llers, n o le ss than fo urte en hundred and odd e lectro -magn e tsare in use

,and mo n th by mo n th this n umbe r increase s

,allbe ing

o f the ho rse-sho e o r U fo rm . A system w hich prom ise s,under like

co ndition s,to give mo re w o rk o ut o f o n e -half o f the e lectro -magn e t

in o rdinary use than w e n o w o btain from the e n tire magn e t,co uld

n o t fail to attract o n e’

s atte n tio n , an d co n strain o n e to put it to

the te st— co st,bulk

,w e ight, allprom ising to be reduced.

The aspe ct under w hich I have attacked this que stio n , as yo use e

,is pure ly utilitarian . I se lected fo r the comparative trials o n e

o f the bells ill o rdinary use o n the lo como tive s and ill the guards’

van s o n the So uth Easte rn Railw ay,fig . 5 . It is o n the table

be fo re yo u . The bo bbin s are each 3 m . lo ng by 3 in . dia

m e ter,and are w o und each w ith 308 fe e t o f No . 18 coppe r W ire

,

w hich w e ighs 35 o z .— o r in all

,616 fe e t

,w e ighing 70 o z . The iro n

co re s are g ill. in diame te r, each w e ighing 3 1, o z . co n n e cted at theback in the usual w ay by an iro n bar. The distan ce from co re to

co re,aa

’

,sho w n o n the fro n t o f the magn e t, isasin ches. But face

plate s o f iro n , b b’

,scre w ed upo n the fro n t o f the co re s

,brin g the

distan ce be tw e e n the po le s do w n to 1133 in ch. The armature

R echerche s sur les me illeures con d ition s do co n struction des Ele ctro

Aime nts. Par 10 Comte Du Mo n ce l, p . 110. Paris, 1871.

158 WORK-VALUE OF ELECTED-MAGNETS [12th Apr

in allre spe cts iden tical w ith fig. 5 and remove d the face-platb b

’

from the fro n t o f the core . An iro n cheek w as substituted fthe o riginal brass o n e at the back o f the bobbin ; but this se e nhardly n e cessary. The iro n tube , sho w n in se ctio n in fig. 1

,al

in back vie w in fig. 6, w as fitte d to e n case the co il . It w .

attached to the back o f the co re by ascrew at a, and cam e 1

flush w ith the fro n t. Its w e ight w as 16} o un ce s ; heavie r, po ssibl

Fig. 6 . Fig. 7.

in proportio n to the core than w as n e ce ssary. The fro n t o f t

co il thus prepared is sho w n in fig. 7,w here ais the co re , 11 in

distan t from the tube b b’

.

Fig. 8 is the fro n t o f the e n case d be ll , w he re bb i s the tube ;

ENCLOSED IN IRON . 159

gg’

isabrass flange on w hich the fittings are moun ted ; h is adisc

,and i i’

an armature , to w hich refe re n ce w ill be made hereafte r.

The batte ry employed w as platin ized graphite and zin c ; theplates 6 in che s x 2 in ches ; the exciting liquid, 1 sulph . ac. 8

wate r.

W ith thre e ce lls on short circuit,the e n cased magn e t, fig. 8,

held 1 °91 o z .

,the magn et o f the train he ll 4 o z. o r in the propo r

tio n o f 1 to An iro n disc (h), 1} inch diameter, w as n e w

cou n te rsunk in the brass face o f the co il, figs. 7 and 8 , w hich

reduced the distan ce be tw e en the tw o po le s o f the magn et fromIi inch to in ch . The magn e t n o w he ld o z.

,as again st

4o z . as before o f the train be ll, o r in the propo rtio n of 1 to

be ing still n o t quite equal to the magn e t of the train be ll .Tw o armature s w e re n o w prepared, in the form o f open seg

me n ts o f acircle , o f the diame te r o f the iro n cylinde r,o r 31»

in che s. They are sho w n in figs. 9 and 10. The uppe r segmen t,

fig . 9, is to be carried by the same co cks that carry the plain

Fig. 10.

zfl

‘mature kk’

,fig. 7 , and is o f like length— 35 in che s ; it is g in ch

W ide and in ch thick , and w e ighs 2 o z . The lo w e r segme n t,

fig. 10,has its ce n tre of mo tio n be lo w at the co cks ll’

,fig. 8 ;

its length, 3153 in che s ; w idth , in ch ; thickn ess, {5 inch ; w e ight,It oz.

With the same thre e ce lls o n short circuit, and the disc in situ

,

the low er segmen t he ld o z .

,o r in the propo rtio n o f

to 1 compared w ith the train be ll magn e t.The uppe r segme n t he ld o z .

,o r in the proportio n o f

to 1.

With bo th segmen ts o n , o n ly o z. w ere he ld, o r to

The fingerat on fig. 10 touches the upperarmature at n , fig. 8 ,andacts w ith‘

xt .

160 WORK-VALUE OF ELECTRO-MAGNETS [12th April,

With o r w itho ut the

The appare n t irregularity of the lo w er segmen t armature , W itho ut the disc

,is explain ed by the fact o f its upper edge n o t reaching

so high as the lo w er po in t o f the iro n core . From thi s it is

e vide n t that the maximum value is to be had from a co il cased illiro n

,w ith the fro n t e nd o f the core expanded

,and a segmen t

armature mo un ted as sho w n in fig. 8 .

The re lative value of the armature s ill the above Table is

TABLE II .

Plain armatureB o th

Low er

Upper

The re lative effe ct o f o utside re sistan ce o n the armature s re

spectively w he n the disc is used, still retain ing thre e ce lls, is givenin the fo llo w ing Table

TABLE III.

The re sistan ce R in allcase s w as asingle co il o f No . 18 copperw ire 308 fe e t in length, similar to the be ll-co ils.

disc the comparative figure s w ere

TABLE I .

With out disc. With disc.

o z, oz.

[1-15] 14-70

162 WORK-VALUE OF ELECTRO-MAGNETS [12th April ,

combinatio n s,sho w ing also the comparative value , asingle e n cased

co il be ing take n as the unit. They are arranged in gro ups, butnumbe red in o rder of value .

TABLE V.

W ITH THREE PLATINI Z ED GRAPHITE CELLS .

Relative

IN SHORT CIRCUIT .

On e train-be ll co il

Cased co il. Plain armature No disc

Lo w er

Upper

Cased co il. Plain armature

Lo w er

Upper

Train-be ll comple te

Cased co il. P lain armature w ith disc

Lo w er

Train-be ll complete

Cased co il. P lain armature 2 co ils R , w ith disc

B o th

Lo w er

Upper

Train-be ll comple te

W ITH 10 CELLS . No RESISTANCE .

Cased co il Upper armature W ith disc

Train-be ll complete

ENCLOSED IN IRON. 163

APPENDIX.

Among the experimen ts made w ere the comparative value o f anordinary train -be ll, w ith or w ithout eased co ils. The proportio nwasas 1 to in favour o f the case s

, w hich is n o t much.

Asingle cased co il, compared w ith a pair o f co ils cased, andarranged as atrain-be ll, w as as 1 to So that asingle co ilgives n early the same w o rk as do e s apair. In the se case s the

armature w as in o n e piece o f the prope r le ngth.

When the armature w as in tw o pie ce s, that is, w he n aSinglearmature w as give n fo r each co il and coupled i nto o n e by abrassstrap, the value fe ll co n siderably . Compared w ith the w ho learmature it w as as 1 to

Imade but o n e trial o f acased co il, w ith aseco nd co ilo f equal

length outside the case . The re sult w as o f an egative characte r.

The ratio be tw e en the value o f the magn e t, w ith and w ithout theSecond co il, w as as 1 to But Mr. Faulkn er

,I be lieve , has

cal‘ried this questio n mo re fully out, and had the pro po rtio n o f

il‘Onand w ire so adjuste d as to o btain alarger in crease o f po w erfi‘

Omgive n materials than o n e could hope for from aso litary ex

Perimen t. This questio n is w o rth pursuing by any o n e w ho has

M ore le isure at his comman d than I can pre tend to claim .

March 29, 1876.

The PRESIDENT : You have heard this sho rt commun ication o f

)mine read, and you can se e at aglan ce that it is the productio n o f

avery busy man , w ho has had time o n ly just to to uch upo n thethreshho ld o f a subje ct, w hich must be in te re sting to te legraphe ngin e ers

,inasmuch as it is amean s o f ge tting much more than

the ordinary amoun t of w o rk out o f the same materials. This, sofar as I am aw are

,is the first re cord o f experime n ts made upon

magn e ts o f this kin d. The prin ciple , it o ccurs to me , is very Old.

During the sho rt in te rval sin ce it first attracted my atte n tio n I

have referre d to the various text-bo oks I have in my library , and.

M 2

164 WORK-VALUE OF ELECTRO MAGNETS [ 12th April,

have searched among commun icatio n s made to so cie tie s— n o t

exhaustive ly. R e cords may be in existe nce , and some o f o ur

members may be able to give still mo re o f the histo ry o f thiscurio us magn e t. Pe rso nally I have n o t yet met w ith much ih

formation . Mr. Ladd is pre sen t, to w hom I re fer as having usedthe form ofmagn e t to w hich I have alluded. His magn et is lyin gupo n the table

,and he w ill n o do ubt give us allthe info rmatio n

he po ssesse s upo n the value o f this class o f magn e ts and the use

he has made o f them .

Mr. LADD : I have but little to say in additio n to the Pre siden t’s

e labo rate paper.

'

I apprehen d that,although abusy man , he has

more time for experime n ting than I,w ho make in strume n ts, have

at my dispo sal. I have be en very much in te re ste d in the re sultso f his experimen ts w ith the particular form of magn e t un der discussie n . Whe n I saw the title o f the paper read this e ve n in g, ito ccurred to me that an oppo rtun ity might offe r for repeating w hatI had reaso n to w rite in the Te legraph Journal ashort time sin ce ,co n ce rn ing the use I have made o f the iron -cased electrO-magn e tfe r the last tw e lve years. From w hat I have sin ce learn e d, Ibelieve this de scriptio n o f e le ctro -magn e t had be e n made be fo re ito ccurred to me to adopt the prin ciple ; but altho ugh n ew to me

then,I did n o t se t fo rth aclaim o f anything n e w . I w as, and

am n o w , satisfied w ith the re sult obtain ed.

The magn e t I have bro ught fo r yo ur in spectio n is o n e I to okthis mo rn ing from an Old e lectric lamp

,and it is the fo rm I have

ge n erally used ; the cen tre is cylin drical, and is made so fo r the

fre e passage o fan o ther part o f the in strume n t to w hich it be lo ngs ;this cylin de r o r co re is jo in e d to the o ute r cylindrical case by aflatiro n ring , firmly un iting the o uter an d in n er cylinde rs and fo rm ingthe bo ttom o f the magn e t o n the uppe r edge o f the o ute r cylin derI fix an o the r flat ring o r flange

,the in n er diamete r o f w hich is

made to come w ithin aquarte r o f an in ch o f the cen tralcylin der ;thus the po le s o f the magn e t are bro ught very n ear to ge ther.

This co nditio n is n e ce ssary fo r the particular w ork required o f the

magn e t ; also that the w ire used Sho uld be stout, say NO. 9,and

con seque n tly o f sho rt le ngth . I tried afe w ro ugh experime n ts thismorn ing w ith the e n cased magn e t

, o f a nature calculated to

166 WORK-VALUE o r ELECTRO-MAGNETS [12th April,

I n ow put o ver the magn et athicker iro n cylin der, and thew e ight n ow is he ld w ith afo rce that n o man in the ro om can

o vercome . This is the Altandas e le ctro -magn et, and I am sure it

is de serving o f the name .

Here I have amagn et o f an o ther kind— it is larger an d I

have greater effects from it. I have an o the r here still heavie rand w ith athicker cover, and this brings us to w hat w e may callthe maximum amoun t o f magn e tism that can po ssibly be oh

tain ed from the quan tity o f e lectricity employed, and that is apo in t o f great impo rtance , as w e utilize that w hich has hithertobe en w asted.Up to the pre sen t time w e have o n ly

,un der o rdinary circum

stan ce s,used o n e pe r ce n t. o f the available po w er o f e le ctro

magn e tism . Yo u se e o n the w all an umbe r o f diagrams. The seare produced by scatte ring iro n filings ove r the po le s e ithe r o f an

e lectro -magn e t o r Altandae e lectro -magn e t, and this (exhibitin g) isthe diagram so obtain ed. The scatte red rays repre se n t lbs.

w aste o ut o f a to tal o f 3lbs. Here w e have adiagram from an

Altandze e lectro -magn e t. You perce ive there are n o scatte red raysatall; W ithin the cover the fo rce lie s

,and w hat w ould o therw ise

be w aste rays are allgathere d up , and, as yo u se e,in to a small

fo cus. I have an o ther diagram taken from the o utside o f the

Altan dae e le ctro -magn e t,and in that w e have n o rays o f fo rce out

side . The o n ly rays o f force w e find are at the tw o extremitie s.Having illustrated the action o f iro n filings unde r various co n

ditio n s o f the Altandze e lectro -magn e t, Mr. Faulkn er w e n t o n to

say : I w o uld sugge st to studen ts o f magn etism, that if theyw ould o n ly fo llo w o ut the course I have take n w ith regard to the sediagrams

,sho w ing the lin e s o f fo rce

,they w ill find very great

assistance from employing them. Whe n I have be e n in the

greate st de spair, I have referre d to diagrams and they havere lieved me from the difficulty.

With regard to the covers made use o f by o ur Pre siden t,he has

produce d 355 times more po w er by using this thin covering ; had heused athicke r he w o uld have succe eded in o btain ing still greaterpo w e r. (Mr. Faulkn er furthe r illustrated the e ffects o f the Altandaa

magn et“by mean s o f iro n filings sprinkled o n paper placed o ver the

ma] ENCLOSED m mo n . 167

magne t, sho w ing the efl'

ects of the additio n o f the iro n covering inconcen trating the rays o f force w ith apparen tly scarcely any

There is an o the r quality w hich comes in to fo rce . Yo u take anelectro -magn et fo rmed o f w ire on ly . You kn o w aco ilo f w ire w ithan electric curre n t passing through it has magn e tism o n on e side ofadiffe ren t character to w hat it has o n the o ther. The raysthatare o n the right side may be called n o rth and those o n the 160.

south. What is do n e by the co vers is, they lead alltho se rayswhich go fo rth in to space o n the right to the right, and tho se o n theleft to the le ftand so in te n sify the actio n . If I n o w se nd an e lectriccurren t thro ugh the co il(o ne end isan orth po le and the o the raso uthpale , w hethe r the co ve rs are o n or no t) that sho w s that the electricalraysare really w hat w e call magn e tism. Tho se w hich go to the

right w e may callthe n o rth and tho se w hich go to the le ft w e maycall the south. The se te rms w ill pro bably have to be mo dified in

Having sho w n you ho w this comes abo ut,the n e xt thing is to

show you w hat I have done in practice . The first thing I did w as,

to take an un cased magn e t from o n e of the best descriptio n s o f

bell-magn e ts, to strip o ff half the w ire from o n e co il, put it in to

this Almndm box, and I go t abe tte r be ll-magn e t w ith aquarte r o f

the coil I had be fo re . I have an o ther varie ty from w hich I havego t very excelle n t results, and w hich has an ice ty o f fin ish abo utit w hich is no t to be fo und in the o rdinary e lectro magn e t, bymeans of w hich yo u are able to apply the Altandamagn et in aspace in w hich yo u cann o t apply the o rdinary e lectro-magn et.More o ver w e can place them o n aplan e , o n e plan e o f 225 inche ssquare w ill give 81,000 .1bs o f fo rce . He re I have an Altandamagn e t w ith an armature o n the to p of 1t ; I make out o f it

The n ext and on e of the most impo rtan t po in ts is the regulatingof the pow er w e have . I have here an Altandae te legraph so under .

The beauty o f this instrume n t is that w e can regulate the po w e r o f

the Altandze magn e t. You saw w he n I put o n aco ver I increase d

168 WORK-VALUE OF ELECTED-MAGNETS [12th April,

the po w er,and so w he n I w an t to regulate agiven amo un t o f

po w e r, I have n o t to co n sult the batte ry but the arrangeme n ts Ihave in the re ce iving instrume n t. W e have here an o rdinary .

e le ctro -magn et in abrass case and o ve r thatasurroun ding cylindero f iro n . Suppo se yo ur battery w eake n s

,o r yo u are se n din g a

lo ng distan ce and your batte ry po w e r is n o t equalto the w o rk ,allyou have to do is to in troduce mo re o f the cylinder. Yo u havehere the mean s o f regulating to aco nsiderable exte n t w ithoutadditio nal battery po w er. Again

,suppo se afte r fin e w eather a

heavy sho w er come s,and e verything ge ts w et and the in strume n t

wo rks sluggishly,screw the cylinder further in .

I have great hopes o f this little in strumen t, o n e o f the late stproductio n s, and it is the best o f them all. I have amo vingbobbin w o rking o n an iro n co re , and I can assure you this is o n e o f

the mo st hon e st e le ctrical in strumen ts in existence . Here I haveon ly o n e iro n cylinder and an e le ctro -magn e t in side . I havealready sho w n you that the iro n covering co n cen trate s the po w er,and the clo se r the cylinders are to the co il the stronger is thepo w er ; there fo re by moving the in n er cylinder o ut w e can Openthe fie ld and thus regulate the pow er to the required stre ngth.

The se Altandee e le ctro -magn e ts can be applied, as yo u se e , to

vario us purpo ses, and the great number of purpo se s to w hich theycan be applied is my excuse fo r o btruding an e w name in to the

busin e ss o f the man ufacturing e le ctrician and in to scie n ce .

I fo und that,n o t o n ly may w e use round covers, but square o n e s.

In an in strume n t I made I had o ccasio n,for the purpo se o f sepa

rating iron from brass filings, to place my magn e t again st asquareo pe n ing. I fo und I hadaro un d fo rce to w o rk in asquare . Of co urse

that w o uld n o t fit, so I co n structedasquare o n e . I w ill sho w yo u thediagram (here athre e-e ight iro n plate w as place d o n each side of

the e lectro -magn e t). This sho w s yo u the w ay in w hich the squareplate ope rate s. Yo u pe rce ive w he re there is iro n allthe rays areharn e ssed, so to speak, and brought in to the space be tw e e n the plate sand the co re ; at each open side they are bursting out and w astingthemse lve s in space . Yo u thus se e

,by using the se co ve rs w e n o t o n ly

get o ut o f an e lectro -magn e t mo re pow er than has befo re be e n oh

tain ed, but w e can also put the fo rce w here w e require it, and can

170 WORK-VALUE o r ELICCTRO-MAGNETS [26th April,

The Fo rty-e ighth Ordinary Ge n eral Me e ting w as he ld o n

Wedn e sday,the 26thApril, 1876, Mr. C. V. WALKER

,


The PRESIDENT having called upo n any gen tleman w ho had

furthe r remarks to make upo n the paper read at the previousme eting, o n The Wo rk-Value o f Electro -Magn e ts En clo sed inIro n

,

”to do so ,

Mr. C. F. VARLEY said — I have afe w remarks to offer,and but

very fe w . In 1855 I made amagn et o f this de scriptio n for

apparatus placed at Amsterdam,but I found that altho ugh w hen

the armature w as attached to the magn et I go t greater liftingpo w er

, ye t at adistan ce from the magn e t the po w e r w as le ss thanthat o f the o rdinary ho rse -Sho e magn e t. I also experimen tedw ith w hat are called in Fran ce aiman ts bo iteua: that is to say, an

electrO-magn e t w ith o n e arm cove red w ith w ire and the o ther o n e

fre e . It is qu ite true that w ith such amagn e t you ge t greaterlifting-po w e r from agive n curren t than might be expe cted

,but for

telegraph w o rk yo u w an t mo re than lifting-po w e r ; you w an t

rapidity o f actio n above allthings, and I foun d this fo rm to be

slo w er in magn e tisingand demagn e tising than the o rdinary e lectromagn e t. Fo r te legraph purpo se s I gave it up ; an d . yo u w ill se eby refere n ce to apate n t o f m in e in 1856 me n tio n made Of e lectromagn ets cove red w ith iro n , but they did n o t an sw er as w e ll as theforms subseque n tly adopte d an d n e w in ge n eraluse .

Mr. HIGGINS : I have tried an umber o f experimen ts w ith e lectromagn e ts, and shall be happy to give the results. They led me tomake afo rm o f magn e t w hich differs to tally from that w hich Mr.Faulkn er has bro ught be fo re us. The e lectro -magn et covered w ithiro n I saw in use about fo urte e n years ago in are lay co n structedby Mr. Varley. That w o rke d stro ngly but w as extreme ly slo wfrom the magn e tism having to impregnate the o ute r casing and

171

lo ng distance from the bottom armature o f the

magn e ts have be e n used in Fran ce fo r se paratingiro n and brass filings. The e lectro-magn e ts used in the ExchangeTe legraph Company

’

s in strume n ts are tube s bo re d o ut o f so lid iro nalittle mo re than o ne-third o f the ir diame te r, and the n split thro ughto the ce n tre to preve n t circulatio n o f induced curre n ts . In the

magn e t o f Mr. Faulkn e r the oute r ng favo urs the circulm'

e n of

induce d curre n ts. It may be split to pre ve n t that ; but in its

pre se n t fo rm it must retard the magn e tisatie n o f the co re . Eve nsuppo sing the tube to be split there w o uld still be charges induce do n the ou te r coating by the high te nsion of the in ne r and e nter

spirals o f w ire o f the mw st, w hich , at the mome nt o f bm km’

gbattery-co n tact, w o uld have u u e efie ct m re tarding the mtio n and demagn etisatie n of the magn e t. The diminutio n of thefie ld o f the magn e t w ould n o doubt reduce its effective fo rce tosome exte n t. The arms 117; Of the magn e ts use d in o ur inma

me n ts w ill re spo nd to curre n ts pe r minute , and w ill do acon side rable amoun t o f w ork. I am quite sure amagn e t cau sed

in iro n co uld n o t po ssibly do that.Mr. SAUNDERS I might justmen tio n thatamagn e t (of the shape

show n in the accompanying figure ), exceedingly small in fo rm,w as

made by Mr. Whitehouse,in 1857, at

the w orksho ps of the old Atlan tic Te le

same fo rm as that o fMr. Faulkn e r’

s.

The o bje ct, ho w ever, w as n o t to ge t

an increase o f po w er, but to arrange


e lectro -magn e tic curren t o n chemical paper by the de compo sitio no f ste e l n e edle s.Each armature w as in sulated and moved o n tw o pin s re stin g o n

the o utside iro n cylin der. The fo rce w ith w hich they w ere keptfrom the in side bar of iro n w as regulated by adjustable spiralsprings. And this fo rce w as gradually in creased from amin imumapplie d to o n e armature to amaximum applied to the east o f the

circle , so that the armature s w ere attracte d in ro tatio n as thecurre n t gradually increased in fo rce .

Each armature w as con n ected’

w ith aste e l n e edle , and 0 11 be ingattracted made co n tact, so that the n ee dle left amark o n the

chemical paper w hich w as ro tating o n adrum .

Mr. TREUENFELD : 1 agre e w ith the experien ce of Mr. Varleythat though an e n cased e lectro -magn e t Sho w s co n siderably greate rpo w e r fo r ke eping the armature , ye t that po w er is much dimin ished w hen the armature is at a distance from the e le ctromagn e t. I think fo r te legraph purpo se s it bears o ut the sug

ge stio n that the w o rk-value can n o t be taken w hen the armature

is clo se to the e le ctro -magn e t, but o n ly w he n it is at a. certaindistan ce

,and I ven ture to say that w hen the armature is at a

distance from the e le ctre -magn e t the w o rking value o f the e n casedmagn e t is n o t large r, but smaller. This can easily be tried byhanging o n e Side o f abalan ced scale ove r the e lectro -magn e t, andw hen using an o n-en cased e le ctre -magn e t it w ill raise agreaterw e ight than if the e lectro -magn e t w e re e n clo sed . This may beexplain ed the ore tically by co n sidering that the lin e s o f magn e ticfo rce from the po le o famagn e t go in radial dire ctio n s to allside s.

Ne w suppo singan e ncased cle ctro -magn e t

,w ith the armature at acertain dis

.

3 tan ce , w e then have the south po le inthe cen tre , and acircular-shape d n orthpo le fo rmed ro und it. Bo th po le s haveradiallin es o f fo rce , and at adistancethe se lin es cro ssand destroy each o ther

,

w hich is n o t the case in an o n -en cased

magn et. If the armature is acertaindistan ce from the en case d magn et, the

174 WORK-VALUE o r ELECTED-MAGNETS [26th April,

great pe rfo rman ce fo r so small amagn e t . Ro berts also co n

structed magn e ts in w hich the gro ove s,in stead o f be ing circular

w ere re ctangular, cro ssin g the face from o n e side to the o the r.

Mr. HIGGIN S : In the magn e t to w hich I have already re fe rredthe perfo rman ce did n o t differ from o thers, except that the spe ed ofthe armature w as ve ry great. The armature w asmade o fan umbe ro f rays from an iro n axis. There w ere tw o se ts o f rays from thisiro n axis w hich revo lved in fro n t o f the po le s o fase rie s o f ele ctromagn e ts placed paralle l w ith the axis carrying the armature s.

The se w e re magn e tised in succe ssio n . Thre e at atime w ere alw aysmagn e tise d. With athermo -pile burn ing te n fe e t o f gas an ho ur,this mo to r w ould lift 40lbs. w e ight o n e fo o t high per minute .

Mr. DARK IN : I repre se n t Mr. Comacho,the in ve n to r o f the

tubular magn e t, an d w ith re fe re n ce to that magn e t I beg to

say that I have fo und the ve ry reve rse o f the actio n refe rre d to byMr. Varley an d o the rs

,that is to say, at adistan ce the magn e t

give s aco n side rably greate r re sult than o n e o f the o rdinary co n

structio n , w hile its po w e r at co n tact is n o t so remarkable . I havea large spe cime n o f this magn e t at o ur o ffice

,and shall be happy

to le t any ge n tleman se e it. It w ill lift 600lbs. adistan ce o f a

quarte r o fan in ch and dro p it again fo rty time s am in ute w ith abatte ry o f six Bun se n ce lls. It co n sists o f co n cen tric tube s.

Mr. VARLEY : If I un de rstan d, this magn e t co n tain s tw o or

thre e co n ce n tric iro n rings [M13 DARKIN Fo ur] and the po w e r is

applied in o n e dire ctio n . It is n o t amagn et o f the de scriptionunde r discussio n .

Mr. DARKIN : No . I gather it is something similar to the o n e

yo u co n structe d .

Mr. VARLEY The magn e t w hich Mr. Darkin speaks o f is of adiffere n t characte r. It co n sists first o f aho llo w iro n co re ; thenro un d it there is acertain amo un t o f w ire . Outside o f that is aniro n tube w ith afurthe r quan tity o f w ire , and o utside that an o the rtube w ith afurthe r amo un t o f w ire and ye t an o the r iro n tube

,

making the fourth, w ith amuch large r quan tity o f iro n w ire . I

have n o t expe rime n te d w ith that magn e t ; but, fo rming an o pin io nW itho ut expe rime n t, I sho uld say if allthe iro n w as put in to o n e

so lid co re yo u w ould ge t abe tte r re sult than yo u ge t n o w .

w e ] ENCLOSED IN mo n . 175

Mr. DAB KIN Would yo u ge t the same re sultat adistan ce ?Mr. VARLEY : I be lieve so .

Mr. F. O. WEBB men tio n ed, that in expe rime n ts made byM. Du Mo nce l w ith the Comacho magn e t

,referred to by Mr.

Darkin , the results of each succe ssive co il w ere tried by itselfandafte rwards adde d toge the r, and then the w ho le serie s w as triedtoge the r

,and it w as fo und that the fo ur cylinde rs to ge the r pro

duced a liftin g po w e r o f tw ice as much as the sum o f the fo ur

taken separate ly. The expe rime n ts w e re carefully made,and in

each case the re sistan ce o f the circuit w as the same,and the same

curre n t passe d in each case . That w as to his m in d co n clusive asto the valu e o f the se compo un d magn e ts .

MAJOR MALCOLM : I fear this So cie ty has n o pow e r to regulatethe names w hich the in ven to rs o f n ew in strume n ts give to them ,

and I sympathise w ith the remarks w hich have be e n made as to thebarbaro us term w hich has be e n co n co cte d fo r the instrume n t underconside ratio n . I have made in qu irie s amo ng ge n tleme n o f far

greater classical pre te n sio n s than myse lf, and they agre e w ith methat the name is utte rly barbarous, and I think it w ill be apity ifthe te rm Altandm system is pe rpe tuated ; stillI suppo se the reisno law to preve n t it. To acertain exte n t I have made e spe riments w ith this apparatus

,and I am ve ry glad to hear w hat Mr.

VonTre ue nfeld and o the rs have said, for at first 1 w as afraid thatI1nd misun de rsto o d the in ve n tio n and w as expe rimen ting w ro ngly.

I tried it in the fo llow ing w ay : I had aco re w hich w as 14} in che slong, and aco ver abo ut 14 in che s ; I hung asmall ste e l ball byavm-yJon g thread in fro n t o f it

, and I found that the draw in gpow er o f the magn e t w ith the cover o n w as less than it w as w iththe cove r o ff— except in o ne positio n , viz . w hen the cove r w as ve rynearly ofi'

. Neverthele ss,as to ho lding po w er

,I have n o do ubt

from expe rimen ts w hich I am satisfied are accurate,if the cover

he cpn t o n , and if yo u have an iro n base co n n ecting the co ver w iththe magn e tize d co re , the holding po w er is e n o rmo usly in creased,ritho n —

gh it isalso very great if the re be n o such co n n e ctio n . Therefore , w hile I can give Mr. Faulkn e r n o credit fo r the name

,I think

he is de serving o f great credit fo r brin gin g the in strume n t befo reus, many uses fo r w hich

'

w ill pro bably so o n deve lo p themselve s. X

17s WORK-VALUE o r ELECTRO-MAGNETS [26th April,

repre se n t more o r le ss the requireme n ts o f the military,and w e

w an t some times to kn o w w hat you te legraph gen tleme n aresaying ; if then w e can tap your lin e w ith po rtable in strume n ts o f

low re sistan ce w e shall have abe tter chan ce of kn o w ing w hat isgo ing alo ng the lin e than if high re sistan ce in strumen ts are used.

It is some time s amatter o f great impo rtan ce to us to kn o w w hatis passing alo ng lin e s, and w e lo ok upo n yo ur w ires as thin gs to betapped

,the refo re w e are de sirous that Mr. Faulkn er and o thers

should be e nco uraged in the pro ductio n o f so unders,&c. of great

se n sitiven e ss and o f lo w re sistan ce ; an d if they w ill o n ly name

them according to some kn o w n law of language they shall havemy be st w ishe s. May they go o n and pro sper.

Mr. LADD I regre t that I w as called upo n to speak at the lastme e ting befo re I had heard the remarks of Mr. Faulkn e r. No

do ubt the se e n clo sed magn e ts are o f great use fo r many purpo se s.

In the case in w hich I used them,I o btain ed mo re po w e r than I

w an ted,an d had to reduce the quan tity of w ire in o rde r to ge t the

le sse r magn e tism fo r my purpo se . No w,if tho se w ho heard Mr.

Faulkn e r at the last me e ting left w ith the ideathat w hat he saidabo ut cased magn e ts w as co rrect, they w ill have some very e rro n e ousimpre ssio n s. A great deal o f w hat he said is— I w as go ing to say“Altan d'ae n o n sen se ; fo r in stan ce , that the o uter casing is something o n ly that preven ts w aste o f magn etism

,and it has n o

.

magn e tism itse lf. This w e kn o w is w ro ng ; the o uter casing fo rms o n e

o f the po le s o f w hat I have alw ays called an ann ularmagn e t.Mr. JOHN FAULKNEB : I have take n the libe rty o f distributing

amo ngst the ge n tleme n pre se n t this eve n ing she e ts o f diagramsillustrating the vario usapplian ce s o f w hat I have cho se n to call theAltandae system . Upo n tho se diagrams yo u find first o f alla

diagram sho w ing the large amo un t o f w aste o f po w er the re is inthe commo n e lectro -magn e t. No . 2 is adiagram show in g thee co n omy o f fo rce the re is in the Altandae magn e t. We say the re isw aste in No . 1

, be cause it can o n ly lift 1 o r 3 ; but in the fo rm of

No . 2 diagram it w illlift 100 o r 300,and I am sanguin e e n o ugh

to be lieve w e can ge tmo re than 100-fo ld o f in crease by apro perlyarranged Altandae . Having go t this great fo rce , as I illustrate d theo the r n ight, I w ill de scribe w hat I applied it to in the first in stan ce .


assisting tho se w ho are thin king some thing o f the matter, o r if Ihave given n ew thoughts to tho se w ho have n ever thought of theimpo rtan ce o f it

,my time w ill n o t have been misemployed . You

can allsee I have tho ro ughly go n e in to the matte r, n o t by o n e or

tw o te sts but by hundreds,o f w hich the se diagrams are the pro o fs.

If I had alittle mo re time I co uld sho w you aphen ome n o n inthis matter w hich w ill become of great impo rtan ce and w hich Ihave n o doubt yo u w ill hear mo re o f in the future .

Briefly it is this : I have observed in diagrams take n from the

o pe n side o f an Altandae e le ctro -magn et w ith flat iro n side s, thatthe curve s o f cen tral magn e tism o r the n eutral po int change d w iththe thickn e ss o r quality of iro n placed acro ss o n e or bo th e nds.From this sugge stio n I have made an in strumen t, w hich is o n

exhibitio n at the Loan Exhibitio n of Scien tific In strumen ts,in the

South Ke nsingto n Museum,fo r testing the thickn e ss or quality o f

iron plate s in bo ilers,faults in te legraph w ire

,&c. &c. I called it

the AltandaElectro -Magn e tic Iro n Plate and Wire Te ste r. Thisis sho w n in fig. 2.

Fig. 2.

A F isan Altandw magn et e n cased be low and o n the tw o sidesw ith iro n plate s ; above is abrass top A G H B

, o n w hich ascale k e is graduated. C C

’

is the core situated in the ce n tre andpassing lengthw ise through the magn e t ; round this is w ound aco ilo f w ire , from the te rminals o f w hich the w ire s L and L’ lead o ff toabatte ry. Whe n the in strumen t is to be used

, the face A D E Go f the magn e t is placed again st the iro n plate to be te sted. A smallcompass is the n passed alo ng the scale lo e un til the n eutral po intis fo un d. The w ho le is the n mo ved alo ng the surface o f the platein various directio n s, and any change o f the n e utral po in t in themagn e t is at o n ce observed bym ean s o f the dipping o f the compassn ee dle . The thickn e ss o f the plate may then be kn o w n by observingthe distance alo ng the scale betw e en the n eutral po in t w hen the

sxcm ssn IN mo n . 179

defect in the thickn e ss o f the plate is likew ise at o n ce o bserved .

to an e le ctro-magnet, w hich appears to have been but little kno w n ,altho ugh first described some thirty years ago . Sin ce my commu

nicatio n was w ritten I have made furthe r expe rimen ts, and havetried armatures of various fo rms, six in all, and in adiffere ntpo sitio n as to the ce n tre of motio n , w hich in all the pre sen tcase s w as in alin e w ith the bo ttom o f the co il. It w ill be se en thatth e tracing o ut the be haviom'

o f the se co ils w ith vario us armature sis very in te resting, and w e ll w orth investigating, alto ge ther apartfrom the ir practical applicatio n . The re sults o fmy further experiments are as fo llo w sWhen w e used the plain armature like Ick’ (fig. but fixed ver

Using tw o such plain armature sat rightangles to each Fis 11

Other, as sho w n in fig. 12 in fact acro ss, the attractio n sho w ed

furthe r rise,reachin g to 48 and 26 o z. re spe ctive ly w ith the

3plat-graphite and 1 Le elanché ce ll.With acomplete disc

,as sho w n in fig . 13; the attrae

Was exactly do ubled, and bemme 64 o s .

,o r 4 lbs. Fig. 12.

In the se six experimen ts the co re w as li

ft-in ch iro n ; in figs. 5

size, o rg-in ch, the size o f the co il and its iro n case be ing

Fig. 13.

180 THE ELECTRIC PEN. [26th April

so that the top o f the segmen t w as dow nw ard, and the straight edgeo n aleve l w ith and facing the iro n core , fig. 15

,that

the attraction w o uld in crease , se e ing that mo re surface

o f armature and magn e t w ould be presen ted to eachFig. 15 . o ther. The reverse w as the case : it fe ll from 192and

135 to 16 and 9so z.

When aw ho le circle armature open like the segme n ts,aw he e l

in fact,fig. 16, w ith fo ur spoke s o r radii , w as use d , the

attractio n ro se from 192and 135 to 32 and 17 o z .

The magn e t w ith the large r iro n co re w ith its le sse rFig. 16 . length o f w ire gave just abo ut the same attractio n asdid that w ith the smalle r core , and the greater le ngth o f w ire

,

w he n tried w ith asingle Le clan ché ce ll.It remain s to determin e , each fo r himse lf, the case s i n w hich

this fo rm o f e lectro -magn e t can be advan tage o usly substitute d forthe o rdinary U-shaped ; regard be ing had to the re latio n be tw e enthe re sistan ce external to the magn etand that o f the magn e t itse lf.With the se remarks I clo se this discussio n

,and w ill n o w call

upon our Acting Se cre tary to give the Me e ting afe w w o rds of

descriptio n o f Ediso n ’

s Electric Pe n ,”the w o rking o f w hich is

exhibited here to n ight by age n tleman w ho has be e n kind e n o ughto atte nd fo r that purpo se .

Mr. SIVEWBIGHT in describing the Ele ctric Pen saidW e are indebte d to the pate n te e in England o f Ediso n ’

s Ele ctricPe n

,Mr. Thomas Clare

,o f Handsw o rth , n ear Birmingham

, w ho

mo st readily complied w ith my re que st to come he re this e ve n ingand exhibit its w orking to the membe rs o f the So cie ty.

The obje ct o f this pen is to pie rce fin e ho le s in she e ts o f paper,

fo rming sten cils,from w hich impre ssio n s are taken . This is do n e ,

w he n the sten cil is o n ce prepared, by passing an inked ro lle r o ve rthe ste ncil

,w hich prints o n to the pape r placed ben eath it. As many

as to impre ssio n s can it is asse rte d be thus prin ted atthe rate o f fo ur to six pe r m inute . The pe n in its e ssen tial prin cipleco n sists o fatube a, fig. 1

,tape ring to asmall po in t I) , an d w ith a

n e edle 0 mo ving in side it. This n e edle is recipro cated w ith greatrapidity, and w hen the po in t is projecte d it is sufficien tly lo ng toreach thro ugh the naner upo n w hich the tube o f the pen re sts ; w hen

182 THE ELECTRIC PEN . [26th April, 1876.

dispe nses w ith the n ecessity fo r this, is w e ll adapted fo r w o rkingthe pe n , and is likely to be large ly employed fo r the purpo se .

The w ires leading from the pe n to the batte ry are flexible toallo w the pe n to be easily moved abo ut in w riting, &c.

The pape r to be pun ctured is placed o n aboard of w hite pin e ,w ith o r w ithout blo tting paper. The pen is he ld and use d in thesame w ay as an o rdinary pen o r pen cil. The tube is taken in the

hand and pre ssed o n the paper in w riting o r draw ing, and the

n eedle then perfo rate s the paper at the rate o f stro ke sper minute . In this way w hat is be ing w ritte n o r draw n is

,so

to speak, pun ctured o n the paper, as sho w n in fig. 3. Some times

fa.

Fig. 3.

prepared paper is used, called metallic, th e tube markin g it asape n cil w o uld

,o r aso lid po in t o fme tal o r black lead is employed ;

o r again , ashe e t o f carbo n ized paper is placed un der the paperto be pierced, and the n e edle po in t pressing o n this sho w s ve ryclearly w hat is be ing w ritte n o r draw n . When the ste n cil (w ritingo r draw ing) is comple te d it is place d in aframe and aroller coate dw ith prepared ink is passed o ver it

, w hich fills the pe rfo ratio n s.A she e t o f paper is the n place d unde r the ste n cil and the ro ller ispassed o ver the ste ncil o n ce o r tw ice and an impre ssion is o btain ed ;this is repeate d as required.

The ink used is the be st prin te rs’ ink,diluted w ith casto r-o il. It is

stated thatany o n e can w rite in the ir usual style w ith ease and fre edomand w ith arapidity e qual to that o fan o rdinary pen o r pe n cil .An office boy can prin t the impre ssio n s

, so the inve n tio n w illdoubtless be o f very great se rvice fo r multiplying copie s o f le tterso r draw ings.The price , I may add, fo r ase t of the apparatus comple te in

e very respect is e ight gu in eas.

The Me etin g then adjourn ed

ORIGINAL COMMUNICATIONS. 183

ORIGINAL COMMUNICATIONS .

Gutta-perchaWorks, 18,Wharf Road, City Road,March 3, 1876.

Society of Telegraph Engin eers.

SIR,— Ou February 4 , 1873, I bro ught before the n o tice o f the

scientific w o rld,thro ugh the So cie ty o f Te legraph Engin e ers, the

cli'

cot w hich light has o n the e le ctrical co n ductivity o f se le n ium .

Since that time the subje ct has be e n inve stigated by severalscientific gen tlemen

,and altho ugh n o thing n ew has be en bro ught

forward it is satisfacto ry to fin d that they allco nfirm my state

ment that the phe nome naare due so le ly to the actio n o f light. Thesubject is n o w attracting the atte n tio n of scie n tific ge n tlemen o f

other coun trie s, and I have had my atten tio n draw n to severalinaccuracie s w hich have o ccurre d in reported stateme n ts made bythose gen tleme n . I there fo re think it w o uld be w e ll if the So cie tyto whom I first commun icated w hat in time may pro ve averyimportant discovery w ill allo w me to place on reco rd afe w particulars as regards the actual disco very o f the actio n o f light o nselenium . While in charge of the e lectricaldepartme n t o f the

laying o f the cable from Valen tiato Heart’s Co n te n t in 1866 I

introduce d an ew system by w hich ship and sho re could commun icate fi'

e ely w ith each o ther during the laying o f the cable w itho utinterfering w ith the n ece ssary e le ctrical te sts. To w o rk this systemitwas ne ce ssary that aresistance o f abo ut o n e hundred megohm s

should be attached to the sho re -end o f the conductor of the cable .

The resistance w hich I first employed w as compo sed o f alte rnatesheets o f tinfo il and ge latin e , and, altho ugh they an sw ered the

purpo se , still the re sistan ce w as n o t co n stan t en o ugh to be satisfactory. While searching fo r amore suitable mate rial the highresistan ce o f se le n ium w as brought to my n o tice

,but at the same

time I w as in fo rmed that it w as doubtful w he ther it w o uld an sw e rmy purpo se as it w as n ot constant in its re sistan ce . I o btain e d

184 ORIGINAL COMMUNICATIONS.

several spe cimen s o f se le nium and in structed Mr. May, my chiefassistan t at our w o rks at Gre en w ich, to fit up the system w e

adopt o n sho re during the laying o f cable s, using sele n ium as thehigh re sistance , and employ the spare members of the staff as

though they w ere o n sho re duty and report to me o n the subject.The arrangement is show n in the acco mpanying diagram,

w hich is

self-explanato ry. It w as w hile the se experimen ts w ere go ing o n

that it w as n o ticed that the deflectio ns varied according to the

in te n sity o f light falling o n the se len ium . On e of many of the

experimen ts made w as as fo llow s

Se len ium closed in Co ver 03 box . Tw oTime . box. Gas in ro om

Cover Off box. Gaso rdinary gas-burn ers

n o t burn ing.

n o t burmng.

alight in ro om.

Resistance in megohms. Resistance in megohms. Resistance in megohms.

1483 1419

1483 1405

1483 1405

In each case the tempe rature in the box w as Fah. Duringthe laying o f the 1873 and 1874 Atlan tic cable s

,the Lisbo n and

Made ira, Made iraand St. Vin ce n t, St. Vin ce n t and Pernambuco ,and the Australian and Ne w Zealan d cable s

,I have w ith succe ss

adopted se le n ium bars pro tected from the actio n o f light.Although I have n o t be en able to devo te the time n ecessary to

tho ro ughly inve stigate such a phe n omena I have take n greatin terest in the subject, and hope befo re lo ng to lay befo re theSo ciety some further experime n ts w hich may prove in tere sting.

Yo urs very truly,WILLOUGHBY SMITH.


to move past the e nd o f the sipho n at auniform rate . In o rderto make the ink run thro ugh the sipho n

,the ink is e lectrified,

and the paper ribbon is co n n e cte d to earth thro ugh the framew orko f the in strumen t. The ink and paper con sequen tly attract eacho ther

,and the ink is spurted o ut o f the e nd o f the sipho n o n to

the paper in asucce ssio n o f very fin e drops. The se dro ps fo rmaco n tinuous straight lin e alo ng the cen tre o f the paper so lo ngas n o curren t passe s through the co il

,but w hen the co il is

defle cted by the passage o f acurren t, the e nd o f the sipho n is

defle cted w ith it,an d traces aw avy lin e o n the paper

,sho w ing

the succe ssive deflectio n s to the right o r the left o f the ce n tralpo sitio n .

The e le ctrificatio n o f the ink is effected by mean s o fan ele ctrostatic in ductio n machin e called the mo use mill

,w hich is drive n

e ither by clo ckw o rk o r by an e le ctro -magn e tic arrangeme n t. The

same driving po w er se rve s to draw alo ng the paper ribbo n pastthe e nd of the sipho n .

2 . GENERAL DESCRIPTION .— Figs. 1 and 2 sho w the fro n t

and side vie w s re spe ctive ly o f a comple te sipho n re co rde r, 111

w hich the mo use mill is driven by an e le ctro -magn e tic arran gemen t. Figs. 3 and 4 sho w o n alarger scale the suspen sio n o f th e

co il and sipho n . A A A are thre e sto ut w o oden pillars w hichsupport the framew o rk o f the in strume n t. B is the mo use m ill

,

w hich is drive n by an e le ctro -magn e t in side the bo x D. E (fig.

1) is o n e o f the te rminals o f the co il o f this magn et,an d imme

diately behind E is the o the r te rminal. The draw e r F co n tain slumps o f pumice -sto n e mo iste n ed w ith sulphuric acid

,by w hich

the atmo sphere in side the mouse m ill is kept dry. The e le ctricitygen e rated by the revo lutio n o f the mouse mill is co nducte d tothe brass rod P and is commun icate d from the po in t o f P to the

plate 0 by co nvectio n o f the air. The plate 0 is in co n n e ctio nw ith the ink ho lder K,

but K is in sulated from the re st o f the

in strume n t by the vulcan ite rod L . The e le ctrificatio n o f K cause s

the ink to flo w thro ugh the sipho n t o n to the pape r w hich passe salo ng in fro n t o f the plate 0 .

The mo tio n of the mouse m ill is commun icated to the paperdrum d by mean s o f the hanging shaft J J

,w hich has alarge

THOMSON’S SIPHON RECORDER . 187

wooden pulley at on e end,and alead coun terpo ise w ith aserie s o f

brass pulleys at the o ther. A cord passe s roun d a the

back of the mouse mill, and ro und the w o o de n pulley at the backof the hanging shaft ; an o ther cord passe s round o n e or o ther of


the brass pulleysat the fro n t of the hanging shafi , and round

w hich is o n the same axis as the paper drum d.

M M are the e lectro -magn ets, be tw e en the po les o f w hich hadthe signal co il S. They lie o n the semi-cylinders Of iro n N l

ORIGINAL COMMUNICATION8 .

splice s n e ed be attempted ; the ro ofing kn ot,w ith e nds n o t less

than o n e -e ighth of an inch lo ng, an sw ers perfectly w e ll, and n ever

draw s. Fig. 5 show s the appearan ce of are efing kn o t be fo re it isdraw n tight. Care must be taken n o t to make a gran ny’

s” kn o t

,

w hich is aptl

to draw . A small variatio n in the le ngth o f e ithe rhand do es n o harm.

THOMSON’S SIPHON RECORDER. 191

4. Susrmssroao r ran SIGNAL Co n . AND Sim o n — The sig nalco iland the sipho n are arrange d upo n aframe w o rk, aside vie wof w hich is sho w n in fig. 3. Fig . 4. sho w s afro n t vie w o f the

suspen sion o f the co il . The w ho le frame w o rk is se cured in its

place be tw e e n the e lectro -magne ts by the clamping scre w 0 at theback. The co il S is suspen ded by asilk thread passing o ver thepulley r . The po sit io n of r can be varied by re leasing the clampw . Inside the co il is astatio nary piece o f so ft iro n 8 a

,the o bje ct

of w hich is to increase the in te nsity o f the magn e tic fie ld in w hichthe co ilhangs. Tw o w e ights hang from the co il

, and can slide up

and do w n the guide s The cords by w hich the se w e ights hangpass behin d abridge 43

,w ho se distan ce from the co il can be alte red

by releasing the scre w y. p and q are the te rminals o f the co ilto w hich w ire s in side the instrumen t leading to T

I and T, areW ed. At the right-hand to p co rn e r o f the co il afin e silkfibre v isattached, w hich leads to apo in t n ear the e nd of asmallvertical leve r u called the multiplie r. Near the to p o f u ano ther

hi n d side o f an alumin ium cradle w hich carrie s the sipho n . Thisalum in ium cradle is fixed to acro ss w ire o n the bridge i i ; byturn ing the scre w ! (fig. 1) to rsio n can be put o n this w ire . At

the back o f the signal co il, and just be hind the po in t of attachmen tof the fibre v

,is an othe r fibre , the o ther e nd o f w hich is attached

to asprin g at 0 (fig. the po sitio n o f w hich can be alte red byturn ing the scre w 71. By turning n o utw ardsagreate r strain is puton the fibre leadin g from o to the signal co il

,and by turn in g 72.

in wards the strain is lessen ed. The bridge i i w hic h carries thesipho n is secured to the plate m m hy the screw j , and is capab\e


o f be ingmo ved backwards o r forw ards w hen j is lo o se n ed. By

pre ssing the plate m m up gen tly, the plate , and w ith it the bridgecarrying the sipho n

,can be lifte d so that the sipho n rise s o ut o f the

inkho lder. The gro ove in the pie ce o f me tal betw e en L and mco n strain s the plate m to rise in such apath that the fibre s leadingto the co il are n o t strain ed by the raising o f the plate . K is the

ink box in to w hich o n e end o f the sipho n dips.5 . THE MOUSE MILL — The mouse m ill is at o n ce an e le ctro

magn e tic e ngin e an d an e le ctro static inductio n machin e . The

e lectro -magn e tic arrangemen ts are as fo llo w s — In the box D isaho rse-sho e e le ctro -magn e t. In the glass case above are te n

revo lving armature s, w hich pass the po le s o f the magn e t at thelo w e st po in t o f the ir revo lutio n . On the shaft w hich carrie s thearmature s, and revo lving w ith it, is acam

,w hich is ate n -sided

po lygo n . (This cam is at the back o f the mill,and is n o t sho w n

in the figure . ) On the edge o f this cam aco n tact-spring re sts,and as the co rn ers o f the cam pass under the co n tact-spring theyraise it, and so break con tact betw e e n it and asto p undern eath it.Whe n the middle portio n o f the straight edges of the cam passe s

,

the spring drops and co n tact ismade . This co n tact de te rm in e s thepassage o f the curre n t from apo w erful lo cal batte ry through theco ils o f the e lectro -magn e t in the box D . The cam is so se t that,w hen the mill revo lve s

,each succe ssive armature is attracted by

the e lectro -magn e t so lo ng as the armature is approaching the

magn e t, but w he n the armature passe s the po le s o f the magn etco n tact is broken an d the attractio n cease s. This make s the axlecarrying the armature s revo lve . To dim in ish frictio n as much aspo ssible the e nds o f the axle are pivo ted o n the edge s Of frictionw he e ls

,w hich w o rk in cups filled w ith o il. By mean s o f the

quadran t slide X (fig. 2) at the back, extra re sistan ce can be

in troduced in to the circuit Of the e lectro -magn e t this le ssen s thestre ngth o f the curre n t passing thro ugh the co ils o f the magn et,and thus reduce s the spe ed of the mill. The lo w e st stud o f the

slide co rre spo nds to the highe st spe ed.

The e lectro static arrangemen ts in the mo use mill w ill be understo od by re feren ce to fig. 6. On the revo lving axle are fixe d tenmetal carriers (c, c

’

, insulated from the axle and from each

194 ORIGINAL COMMUNICATIONS .

in creasing, but the rate of its in crease go e s on in creasing to o . The

actio n w ill take place if the po ten tial of the inductor I differs e ve rso little from that of the in ductor I’. If I w ere n egative re lative lyto I

’

to begin w ith,then an egative charge w ould accumulate o n I .

It w ould be difficult, if n o t impo ssible , to reduce I and I’ so exactlyto the same po te n tial as to preven t I from getting highly chargedafte r afew turn s of the mill .The carriers and in ducto rs are coate d w ith parafi n w ax to

preven t sparks from passing acro ss the air space be tw e en them.

6 . THE LOCAL BATTERIES.— The batterie s employed to ke ep

the e lectro -magn e ts M M and that in the mo use millactive aremodificatio n s o fDan ie ll’s battery, de sign ed so as to have very littlein te rnal re sistance , and are called Tray ce lls. They co nsist o f

large flat w o oden trays, lin ed w ith lead to make them w ate rtight,and having fo r the po sitive metalashe e t o f thin copper in the

bo ttom o f the tray. In the four corn ers o f the tray four sto n ew are

props are placed, and o n the top o f them rests azin c gratin gw hich fo rms the n egative me tal. The tray is filled up w ith aso lutio n of sulphate Of zin c, and sulphate of copper crystals aredropped in o n the bo ttom plate . Th e zin c is surro un de d w ithashe e t o f sto ut parchmen t paper to preven t the diffusio n o f the

sulphate of coppe r so lutio n from pro ducing copper depo sits o n thezin c plate . The trays are cOImected to each o ther by be ing piledo n e o n the top Ofan o ther, so that the copper of o n e is co nn ecte d tothe zinc Of the o n e be lo w it

,by con tact o f the lead sheathing o f the

uppe r o n e w ith the fo ur co rn ers o f the zin c plate be low o n w h ichit re sts. The advan tage o f this fo rm o f ce llis its extreme ly lo win te rnal re sistan ce . It requ ire s con stan t atten tio n to ke ep it ine fficie n t o rder. (Se e

7 . DIRECTIONS FOR SETTING UP THE BATTERIES .— Each o f

the lead trays must first be carefully coate d w ith varn ish,o ve r

the bo ttom,side s, and edge s. Spirit varn ish made w ith she llac

or o rdinary varn ish w ill do ve ry w e ll . Care sho uld be taken n o t

to varn ish o ver the strip o f coppe r w hich is so ldered to the bo ttomo f each tray . The under surface o f each thin copper plate is alsoto be varn ished. When the varn ish is dry, place the she e t of

copper in the tray w ith the varn ished side do w n , and, cutting a

THOMSON’S SIPHON RECORDER. 195

w t in the cen tre o f the copper she e t, bring through the strip o f

co pper w hich is so ldered to the bo ttom o f the tray ; ben d the stripand spring it so that its end pre sses firmlyagainst the upper surfaceo f the copper plate , taking care that bo th are scraped clean at the

Each lead tray sho uld have asto ut copper w ire soldered to it,proje cting about three inche s fromEach zin c is to be pro tecte d by asquare of parchmen t paper

ben t round be low it, and fo lded n eatly at the co rn ers and fixedw ith sealing waxfi‘ Care must be taken that the edge o f the paperbe gen erally i in ch (and in n o place le ss than 1» in ch) abo ve theuppe r le ve l o f the bars o f the zin c grating. It must be bo un dfirmly to the zin c by tw in e passin g under the parchme n t paper andtied o ver the zinc abo ve ; also by alo ng pie ce o f tw in e several

To suppo rt apile o f trays, take four blocks o f w o od o r sto n e ,

each fo ur o r five in ches square in ho riz on tal dimen sio n s and o f

any co n ve n ien t he ight, and place them o n the flo o r in positio ns tohear the fo ur co rn ers o f atray. The pile must be so placed as togive ready access to each o f its sides. Putapiece o f thick shee tgutta-percha, six in ches square , o n the to p o f each o f the w o ode nsquares, and the n lay do w n the first tray upo n them, se eing thatit is pro perly leve lled. This is most easily do n e by pouring asmall quan tity of w ate r in to the ce ll, and se e ing w he ther it lieseve n ly o ver the bo ttom. Put fo ur sto ne ware blocks, each abo ut1 1} inch cube , in the co rn ers o f the tray, o n the top o f the coppe rshe e t,and put o n e o f the zin c gratings re sting w ith its fo ur corn e rso n the se props. Put aso lutio n o f sulphate o f zin c o f spe cific

gravity about 11 in to the tray,1‘ pouring in first be tw e en the

thanmmthe bight ro un d the vertical co rner o f the zin c, and press itagainst the


edge o f the tray and the parchmen t paper, and afterw ards fillin gup to the leve l o f the top o f the zin c grating by pouring some o f

the so lutio n dire ctly o n the zin c over the paper. Se e that the to pcorn ers o f the zinc, and the bo tto m co rn ers o f the tray to re st

upo n it, are allprope rly tin n ed, scraped clean , and dry . Place alead tray resting w ith its fo ur corn ers on the uppe r projectin gcorn ers o f the zinc. Place four sto n e w are props in the co rn ers o f

this se co nd tray, put a se co n d zin c upo n them ,and fillw ith

so lutio n as befo re . Pro ce ed thus un til apile o f from six to te n

trays,o n e o ve r the o ther, is made and filled w ith liquid . So lde r a

stout copper w ire to o n e o f the co rn e rs o f the top zin c,to serve as

an e lectrode . In the same w ay make asman y pile sas are require d.

Leave aspace at least o n e fo o t broad be tw e e n each pile and itsn e ighbo ur. Con n e ct the pile s in se ries, the top zin c o f o n e pileto the lo w e st lead tray o f the n ext o n e .

The crystals o f sulphate o f coppe r to be used should be bro kenin to smallpiece s, and w e ighed out in quan titie s of an o un ce each .

To put the batte ry in actio n drop in four o un ce s to each ce ll ; o n e

o un ce separe tely o n each side,distributing it as equally as may

be alo ng the space be tw e e n ”the sto n ew are props. In putting in

the crystals be care ful n o t to le t any fall in side the parchm e n t

paper, or in co n tact w ith the z in c. As so on as the sulphate o f

copper is put in , the batte ry sho uld be allo w ed to w o rk, e ither o n

sho rt circuit o r o n the circuit w hich it is in te n ded for.

From thre e to six ce lls are required to drive the mo use mill .The n umber to be applied to the magn ets M M varie s w ith thecircumstan ces of the case ; it may be anything from o n e to tw en ty,o r even mo re . Separate se ts o f ce lls sho uld be used fo r the

magn e ts and fo r the mill. If the same se t is used fo r bo th,— thatis to say, if the co ils o f the magn e ts are to be lo o ked o n as ashun t

applied to the batte ry w hich is drivin g the m ill (o r vice versa) ,then the w ho le n umber o f ce lls in use sho uld be applied to eachcircuit. The practice o f using part o f the batte ry employed tow o rk the magn ets to w o rk the mill also is very obje ctio nable . A

w ire from the zin c po le o f the pile or piles in te n ded fo r th e

magn e ts come s to the te rminal UI (fig. 2) from the copper po le toU3, and aw ire from an intermediate tray in the series to U2 .


9. ADJUSTMENT OF THE MOUSE MILL — If the M illdo es n o t

run fast enough— 1st

,Alte r the quadran t slide X (fig. 2) if n o t

already o n the stud o f highe st speed ; 2nd, Lo ok w ell to the adjustmen t o f the co n tact-breaking spring at the back ; 3rd, Se e that thecups are w e ll supplied w ith o ilin w hich the fri ction rollers w o rkthat bear the e nds of the main shaft ; 4th, If it still goes to o slo w lymore battery po w er must be employed .

The e lectro -magn etic co n tact breaker at the back con sists of tw o

platinum po in ts, o n e of w hich is fixed,w hilst the o ther is carried

up and do w n by aste e l spring w hich is raised at in tervals by thecam . If the se platinum po in ts are separated to o much, the e lectromagn et w ill n ot act on each carrier in succe ssion so long atime as

it o ught, and dimin ished efficien cy is the re sult. Again , if thepo in ts remain in co n tact to o lo ng, the e le ctro -mague t w ill con tin ueto act on each carrie r after it has passed its po les, and thus te n dpow erfiilly to re tard its progress. Hen ce the adjustme nt of this

spring,by turn ing the screw w hich raises o r depresses the lo w e r

co n tact, is mo st impo rtant ; but w hen o n ce se t right it w ill remainso for alo ng time .

If the ink is in sufi cien tly electrified w he n the mill is runn ing

properly,and ge n e ratin g e lectricity— lst

,Alter the distan ce of the

rod P from the plate 0 . Ge n erally abo ut tw o o r thre e in che s isfound to be the be st distan ce ; but this depe nds o n the state o f the

atmo sphere , &c 2nd, Se e that the in sulation is n o w here impaire d

by dust. If the silk fibre attached to the sipho n has any dust upo nit, acame l

’

s-hair brush o r feather w illremove it. The vulcan iterod L, in particular, must be kept fre e from dust, and also theme tal w o rk n ear it. It is some times n ece ssary to clean the vul

can ite rod L by w ashing it w ith w arm w ater and alittle soap, and

then drying it carefully.

’ The paraffin tube,w hich in sulate s the

rod leading from the insulate d in ducto r to the rod P,w illalso

requ ire o ccasionalclean ing.

When the mouse millfails to generate electricity , although o the r

w ise run n ing w e ll, it w illbe n e ce ssary— lst,To take off the to p

Wh en o thermean s o f getting L to insulate properly fail, it should be pain te dw ith varn ish , prepared by disso lving scaling in warm spirit. This varnish shou ldbe laid o n w hile ho t.

THOMSON’

8 SIPHON RECORDER . 199

and carefully remo ve the insulate d inducto r, and se e that its in

sulation and that o f the carriers is pefi ct ; 2nd, Make sure thatthe four springs make co n tact properly w ith the brass pins as theycome ro un d in successio n . Every pro visio n is made fo r the adjustme nt of thme springs, o r for the insertio n o f n e w o n e s, w hich iseasily efl’

ected. Se veralsets o f spare electrostatic springs, ando n e spare e le ctro-magn etic co n tact-sprin g for the driving circuitare sen t w ith each instrumen t ; 3rd, Supply the draw e r F w ithsulphuric acid by po uring afe w drops o n each piece o f pum ice .

The strongest commercial sulphuric acid should be employe d forthis purpose , and should be pre pared by bo iling it fo r half an hourin aFloren ce flask along w ith alittle san d to facilitate ebullition

,

and afe w crystals o f sulphate o f,ammo n ia. The flask sho uld be

supporte d by are to rt stand over aspirit lamp o r o ther co nve n ien tsource of heat, be n eath w hich is placed apan o f cold ashes o r o therarrangemen t to pre ven t any injury be ing do n e in case the flaskbreaks.

’

If too much e lectricity is gen erated, the siphon w ill n o t markw ell, and w illsometimes vibrate late rally un less some is draw nOff by apo in te r in co nn ection w ith the o utside of the case and

d ire cted to w ards the rod P . If the in strume n t is n o t pro videdw ith such apo in ter the w an t can be easily supplied by attachingapie ce o f w ire abo ut 6 in ches lo ng to the scre w handle o f the

draw e r F. The lateral vibratio n of the sipho n may be furtherpre vc by e n closing the pape r (w hile run ning) in abox co n

paper. The paper may be pre pare d by soaking it in aso lutio n o f

W o parts o f n itrate o f ammon iain 100 parts o f w ate r , and the n

drying and re -ro lling it. This salt, be ing adeliquescen t, ke epsthe paper slightly darnp by abso rbing mo isture from the atmo s

phere , and by thus in creasing the co nducting po w er o f the pape r,

pre ven ts the lateral vibratio n s o f the sipho n .

If sparks are se e n passing be tw ee n the in ductors and carrie rs at

A go od plm of ko eping the mouse milldry, in s cold and damp climate , is totake o ut thc drawc , aud put in itaplace aco il, or bend Of lead tube , through

w hich acurren t o f ho t w ate r or steam is kept passing fromasmalltin bo iler, keptho t by agas jct o r by the flame of acmidlc.

200 ORIGINAL COMMUNICATION8 .

any place , they w ill be due to adefe ct in the coating of paraflin

w ax. Such defect can be easily repaired by a little ho t me lte dparaffin laid o n w ith abrush .

If sparks are se en at the co n tact o f the revo lving cam at the

back and the spring that rests o n it, they w ill be due to ade fe cto f in sulation o f the battery w ire o r e lectro -magn e t co il , w h icho ught to be remedied w ithout de lay .

10. ADJUSTMENT o r THE PAPER — TO release the pap er , turn

the handle f in adire ctio n oppo site to the mo tio n of the han ds o f

aw atch. Thus the roller e isallo w ed to fall abo ut an e ighth o fan

in ch,and the pape r is qu ite fre e , so that it may he slippe d out

w ith ease , and, though the driving drum d revo lve s, the paper isn o t draw n along . 1 0 clutch the pap er against the driving drum ,

turn the handle f in the reverse dire ctio n .

To regulate the distance of the pap erfrom the poin t of the siphon ,

turn the milled head It.To bring the lin e made by the siphon to the middle of the paper ,

lo o sen the clamping-screw H,w he n the w ho le paper stage G G

can be easily moved backw ards o r fo rw ards to the de sired po sitio n .

To make the pap er run evenly be tw een the rollers d and e , turn

the small scre w Io, w hich w ill e ithe r e levate o r depre ss the n eare r

e nd o f the ro ller 6 un til allw orks true .

To alter the sp eed of the paper, shift the band in fro n t from on e

pulley to an o ther. If n e ce ssary alte r the spe ed o f the mill .11. ADJUSTMENT or THE SIPHON AND SIGNAL Com — A large

n umber o f fin e glass tube s fo r siphon s is provided w ith eachinstrumen t .

” The siphon s are made from them as fo llo w s — Takeo n e of the small pie ces o f tube and pre sen t it to the heate datmo sphere surrounding any small flame

,such as that o f amatch,

in aconvenien t position to allo w o n e part to drop by its o w n

Sho uld these prepared tube s n o t be at hand, they can be easily made thusTake apiece o f so ft glass tube , about o n e quarte r o f an inch in diame ter, the

thickn ess o f its w all be ing about o n e-sixth o f the w ho le diameter. So ften about

o n e inch n ear the middle in an o rdinary gas flame , or, better still, o ver aBun se nburn er, slo w ly turn ing it ro und the w ho le time . Wh en sufficien tly so ften ed, removeit from th e flame and pull the ends apart un til the tube is so draw n out that it is

o f the de sired diameter. Break the fine tube thus produced into piecesabout fourmches lo ng.


low ered by turn ing the scre w r w ith asquare-po in te d key. It is

moved backw ards,fo rw ards to the right, o r to the left, by easing

the screw w, shifting as de sired, and then reclamping.

To attain the se co nd o f the abo ve co ndition s in con n ectio nw ith the first

,the thre e screw s n , j , and l(figs. 1 and must be

man ipulated.

By lo o se n ing j and sliding the bridge i i backwards or forw ards,the first approximatio n is obtain ed . Then the screw s n and lmust

each be turn ed so that the ste e l spring conn ected w ith n,and the

to rsio nal e lasticity of the w ire attached to I, may re-act o n eacho ther, so as to make the signal co il hang in alin e w ith the po leso f the magn et.Lastly, to make the sipho n hag vertically, the screw j w ill

pro bably require to be undo n e , the bridge i i slightly shifte d,and

an o ther to uch given to Z . This last adjustment is the o n ly on e

required in gen eraluse .

Se e that the siphon do es n o t stick o n account o f the shorter end

be ing to o lo ng, and touching the bo ttom o f the ink box.

The mo st suitable ink fo r the re corder is the be st so luble an ilin eblue . Put as much o f the crystals as w ill stand o n the small bladeo fape n kn ife in to a3 o r 4 dz . bo ttle o f w ater, and shake themup, and yo u w ill immediate ly have aperfectly fluid ink o f ade epblue co lo ur. This ink is supe rio r to any ordinary kin d, be causeit do e s n o t thicke n or precipitate , and, in the form o f crystals

,is

far m o re po rtable .

12. GENERAL DIRECTIONS .— The size o f the signals may be

varied by mean s o f the shun t attache d to T2 (fig.

The se n sitive n e ss of the in strume n t may be in creased in se veralw ayslst. By altering the co n tact-springs o f the e le ctro -magn e ts.

When the co n tact-springs are arranged as show n in figs. 1 and 2,

the magn e t co ils are co nn e cte d up in series. If the spring Ylbe shifte d o ver to the stud Z, the springY3 remain ing disco n n e cted,the right han d co il o n ly is in circuit. This gives alow degre e of

se n sibility. But if,w hen Y, is co nn e cted to Z, the spring Y~

8 be

put upon the stud to the left o n w hich Y] is show n as re sting infig. 2

,then both co ils are in circuit, and are jo in ed up in multiple

THOMSON 'S SIPHON RECORDER. 203

Except w ith a batte ry o f exce ptionally high re sistance , thelastarrangemen t is the most se n sitive of allthre e . Each o f the

co ilshas are sistan ce o f abo ut 8 o hms ; co nsequen tly, w he n the

firstarrangement is adopted, the to tal resistan ce is 16 o hms ; w iththe second arrangeme n t 8 ohms ; and w ith the third arrangement4 olnns.

End. The sensibility o f the in strumen t may be in creased bylowering the brigo a, fig. 3 (by lo o se n in g the clamp y), so as tolengthen the distance be tw e e n it and the signal co il .3rd. By usinglight w e ights. The o n ly limit to this is that the

Weights must be sufi cien tly heavy to bring the co il (after be in gdeflected) back to its n o rmal po sitio n so quickly as to leave n o

sensible in te rval be tw e e n the ce ssatio n of the curre n t and the

correspo nding re turn o f th e co il. Sin ce the first in troduction o f

me recorder it has be e n fo und that the w e ights may be much

to give sufficien t dire ctive fo rce .

4th. The se nsibility may be greatly increase d by bringing thetwo cords by w hich the w e ights hang from the co il close to gether.

The clo se r the se threads are to o n e an o ther the less w ill be thedirective fo rce on the co il , and the greater w ill be the sen éibility .

Agood plan o f bringin g them ve ry clo se toge ther is to tie athreadround them just be lo w the ir po in ts of attachmen t to the co il.They may thus be brought so n ear each o ther as to to uch . Theyshould then be bro ught equally clo se to on e an o the r w here theypress on the bridge a', so that they may han g paralle l be tw ee n thecoil and the bridge . This mode of in creasing the se n sibility o f the

instrumen t is re comme nded in prefe re n ce to the 3td me thod givenabove

,be cause w hen the w e ights are much lighte n ed the stability

of the co il is lesse n ed, and it is liable to be afl'

ecte d by any n u

steadin ess of the in strume n t o r of the'mble ; w hile by bringing

toge ther the suspe nded co rds of the w e ights the dire ctive fo rcemay be reduce d to any exte n t w ithout takin g aw ay ficm the

stability of the co il .5th . The leverage o f the multiplier u can be in creased by

low ering the po int o f attachme n t o f the fibre leading to the co il,o r

by raishlg the po in t ofattachmen t of the fibre leading to the siphon .


On short circuits the multiplier u can be dispe n sed w ith , andthe co il co n n ected dire ctly to the sipho n by asingle fibre . The

multiplier is removed by taking out the tw o scre w s (sho w n in

fig. 4,just be lo w w ) w hich se cure the frame w hich carries the

multiplier.

Whe n the in strumen t is to be o ut o f use fo r (say) some hours,the battery should be disco n n e cted from the e lectro -magn e ts byturn ing the sw itch V. The mouse m ill should be stoppe d byturn ing X (fig. 2) do w n so as n o t to touch any o f the studs. The

sipho n should be lifted out o f the in k-bo ttle by raising m m , and

the ink should be sucked o ut o f the sipho n so as to preve n t it fromdrying in the sipho n and causing it to clog. When the siphon isbe ing sucked care must be taken n o t to strain the fibres.

Whe n the in strume n t is to be o ut o f use for ashorter time , theco rd w hich drive s the paper drum may be placed o n the pulleygiving the lo w e st spe ed, so as to w aste as little o f the pape r aspo ssible ; o r the paper may be e n tire ly stopped by turn ing thehandle f, w he n the ink from the sipho n w ill accumulate o n it in

alarge drop . The mill sho uld n ever be stopped w ithout the sipho nbe ing raised and sucked.

When the in strumen t ro om is o n the gro un d-flo o r,abrick o r

sto n e pillar should be built fo r the re co rder to stan d upo n . The

top o f this should be about n in e inche s be lo w the leve l o f the table .

The uppe r part o f the re co rder the n proje cts through alarge squareho le in the table . This arrangemen t preven ts the reco rde r frombe ing shake n by any moveme n ts o f the table

,and it brings the end

o f the sipho n do w n to aco nve n ien t leve l . Whe n apillar risingfrom the gro und can n o t be used, the recorder sho uld stan d o n a

sto ut bracke t projecting from aw all (n o t apartitio n) at the same

distan ce be lo w the leve l o f the table . The in strumen t should beplaced so as to be w e ll lighted from the le ft.

13. CONNECTIONS ro n SENDING AND RECEIV ING.— Tu o rder

that the signals sen t from astatio n may be reco rded o n the re

ce iving in strumen t at that statio n , it is n ecessary to sen d aportio no f the curre n t thro ugh the co il o f the reco rder at the se n dingstatio n . The po rtio n o f the curre n t w hich passe s thro ugh the co il

o f the re co rder at the sending station may e ither rejo in the re

THOMSON S SIPHON M OORDER . 207

through the co iland shun t. The co n tact-piece D allo w s the

cable toi

be discharged to earth during the movemen t o f the sw itchfrom “

se n d to “rece ive .

”The le ver o ught to make co n tact

w ith D befo re it breaks co n tact w ith S, so that the cable may beforan instan t co n n ecte d to earth through n o o ther resistan ce thanthe very smallo n e be tw een T, and T, .

It w ill be se en that the batte ries are reversed at the tw o statio ns ,or, what amoun ts to the same thin g

, the po sitio ns o f earth andline are diffe re n t o n the tw o keys. This is n ecessary in o rde r thatthe sending and re ce iving signals may be reco rded in the same

direction,w hen the arrangeme n t sho w n in fig . 8 is used .

5 14 . SECOND Marrie s o r Aaaaxemo CONNECTIONS.— The

method sho w n in fig. 8 w astes n o n e o f the curre n t at the se ndingstation . The po rtio n o f the curre n t w hich passes thro ugh the co ilat the sen ding statio n rejo in s the main body at T, . Fig . 9 show s

an arrangeme n t in w hich the portio n o f the curre n t w hich reco rdsthe signals at the se nding statio n is allo w ed to go to earth . At

the se ndin g e nd the co n tacts numbe red 2 and 3 are made,and

N o . 1 is broken . At the re ceiving e nd No . 1 is made and No s. 2

and 3 bro ken . The curren t from the key e n te rs the recorde rSimultan e ously at T, and T, , w hich are the re fore at the sam e

Po tential. Be tw e e n T, and the earth there is ahigh re sistan cemy of ohms— w hich, ho w ever, may be varied to suit

difi'

eren t cases. Sin ce the ve ry lo w resistan ce be tw e en T, and T,in n exce edingly small fractio n o f the high re sistan ce that the reisbetw ee n T, and earth, T, w ill be at apo te n tial very little lo w e rthan that o f T, . But T, is at the same po te n tialas T, , co n seque n tlyT, isat apo te n tial very little lo w e r than that o f T, . There w illtherefore be afe e ble curren t from T, to T, through the signalcoil.

To receive , the co ntacts Nos . 2 and 3 are bro ken,and No . 1 is

made . T, is thus put in direct co nn e ctio n w ith the earth,and

the re ce ived curren t e n te rs at T,, passe s thro ugh the co il,and go es

to earth at T, . In this arran gemen t the rece ivedand sen t curre n ts,w hen o f the same name , pass thro ugh the signal co ilin the same

directio n . There is, therefo re , n o n e e d to reve rse the batte rie s atthe tw e en ds as in the fo rmer arrangeme nt. The sw itch must be


so de sig ned that w he n it is turn ed o ve r to send, co n tact Nois first made

,then No . 1 broke n

,and lastly, No . 3 made ; a

w he n turn e d o ve r to “rece ive , No . 3 must first be broke n

,th

No . 1 made,and lastly No . 2 bro ken . This o rder pre serve s t

co il from rece iving any vio le n t sho e Ir bv the discharge o f 1

cable .

Re co rde r

The se nding signals reco rded by mean s o f the seco n d o f

above arrangeme n ts are ve ry much mo re legible than tho se 0

tain ed by the first. The latter are much mo re abrupt and je rkThis is e specially the case w he n co nde n se rs are used, o r w he n tautomatic tran smitter is employed (se e

2 10 ORIGINAL COMMUNI CATIONS .

shun t co il me n tio n ed in the pre ceding paragraph, and allow the

re st o f the circuit to remain un changed . Observe the deflectio nn o w obtain ed

, an d call it d. If w e callthe re sistan ce o f the

battery shun t S , then R ,the re sistan ce o f the ce ll, w ill be foun d

by the follo w mg fo rmulaD d

R Sd

This formulaho lds go od only w hen the re sistan ce exte rnal to thece ll is ve ry great compared w ith that of the ce ll itse lf. It is

therefo re n ece ssary, w hen the exte rnal resistan ce is that Of the

galvan ome ter alo n e , that the galvan ometer should n o t he shun tedthe defle ctio n may be brought w ithin reaso nable lim its by applyingstro ng directing magn e ts. If

,ho w ever,asufficien t extrare sistan ce

be put in to the circu it, the re is n o Obje ctio n to the use o f a shun to n the galvan ometer. It sho uld, ho w ever, be bo rn e in m in d thatthe abo ve fo rmulais n ever mo re than approximate ly true , and thatit is mo re and mo re n early true the n eare r the ratio o f the exte rnalto the in te rnal re sistan ce approache s to infin ity. He n ce the h ighe rthe external re sistan ce is the mo re n ear w ill the re sult given bythis formulabe to the truth. This te st is n o t applicable to abatteryo f high re sistan ce

,but it is by far the be st te st fo r tray ce lls

,o r

eve n fo r some o f the mo re o rdinary forms of batte rie s. Whe n aquadran t e lectrome te r can be used

,the te st is exce edingly simple .

Observe D, the defle ctio n obtain ed w hen the tw o po le s o f the

battery are con n ecte d to the tw o e le ctrode s o f the e le ctrometer.

Next observe d, the deflectio n obtain ed by con n e cting the po le s o fthe batte ry to the e le ctrome te r, the battery be ing shun ted thro ughthe co il w ho se resistan ce is S . Then as before

D dR S

d

When the e lectrome te r is used this formulais rigidly accurate}an d the te st is applicable to abattery o f any re sistan ce w hatever.

A co n ven ie n t modificatio n o f this te st is to use abox Of adjustable re sistan ce co ils as the batte ry shun t, and so alter S un til the

Except foraslight change in the e lectromo tive force o f ace ll during th e test,due to po larizatio n .

THOMSON ’

S SIPHON RECORDER 211

secon d de fle ctio n d is exactly half the first deflectio n D. Then Bw ill be equal to S .

In o bse rvin g d care must be take n n o t to allo w the curre n t to

run thro ugh the Shunt co il fo r any co nsiderable length o f time,as

the co il be comes rapidly heate d and so alte rs in resistan ce . In

orde r that the rate o f heating sho uld be as small as possible , theshunt co il should be made o f thick w ire . If the deflectio ns D anddare so n early equalthat the differen ce betw e en them is smallcompared w ith e ithe r, the n the resistance o f the shun t is to o great,and ashun t o fle ss re sistan ce o ught to be used .

The resistance o f the tray ce lls depe nds,o f course

,Upo n the ir

size . They have se ldom le ss in te rnal re sistan ce than O'l ohm,

and should n e ve r have mo re than O°5 o hm. It is very impo rtan tthat allthe ce lls in acircuit should have approximate ly the same

17 . To Tsar THE ELECTROMOTIVE FORCE o r THE BATTERY.

The e lectromotive force o f each o f the tray ce lls should he testedoccasio nally by

'

Comparing it w ith the e lectromo tive force o f a

stan dard ce ll o f a constan t kin d . The standard ce ll may be aMin o tti’s or any o ther fo rm o f Daniell’s e leme n t

,and it should he

se t apart and n o t used fo r any o ther purpose except fo r testin g,80 that its e le ctromo tive fo rce may remain fairly co nstant. The

method o f te sting is as fo llow s : Jo in up the battery to be testedin circuit w ith ahigh resistan ce and agalvan ome te r, and n o te the

defle ctio n D,just as in the pre vio us te st. If the re sistan ce o f

the galvan ome ter is o f itself so great that the re sistance o f the

ce llis in sign ifican t as compared w ith it, then it w ill be un n ecessaryto in tro duce an y o ther resistan ce in to the circuit. Next substitutethe standard cellfo r the battery to be te ste d, ke eping the rest o f

the circuit unchanged, and n o te the deflection D’ given by it. In

this case also the resistance exte rnalto the cellshould be ex

EMF of batte i-y EMF Of standard cellx (9 .

In this w ay the electromo tive fo rce ofany given battery can beexpresse d in terms o f that o f the standard ce ll, and it is n o t n ece s

sary for practical purpo ses to kn ow w hat the electromotive forcer 2


of the standard ce ll is in abso lute un its, so longas it can be reliedo n to remain co n stan t. If it isaDaniell’s cellin good condition

its e lectromo tive fo rce w illbe almost exactly on e volt.In the above formulait is assumed that the resistances bo th of

the battery to be tested and of the standard cellare in sign ifican tas compared w ith the o ther resistan ce s in the circuit w hich remain

un changed during the experimen t. If,ho w ever

,the re sistan ce s o f

the battery and standard ce ll w ere re lative ly considerable , thefo rmulaw ould require to be mo dified as fo llow s Let R, be the

sum o f the externalre sistan ce s in the circuit,w hich is the same

bo th fo r D and D'

. Le t r be the re sistan ce o f the batte ry to betested and le t r’

be the resistan ce o f the stan dard ce ll. ThenD (R0 r)

EMF of battery EMF of standard ce ll xD

’

(Bo f )If the quadran t e le ctrome ter is used the te st be comes exce edinglysimple . Le t the deflectio n D be observed w hen the po le s o f the

give n battery are applied to the terminals o f the e lectrome ter , and

le t the deflectio n D'

be observed w he n the standard ce ll is applied,

n o re sistan ce be ing used in e ither case . Then

EMF o f battery EMF o f standard ce ll xD7)

If the e lectromo tive fo rce o f any o n e ce ll is Observed to fallbe lo w the ave rage , o r much be lo w that o f aDan ie ll’s ce ll in go o dco nditio n , the ce ll e ithe r re quire s to be refre shed w ith crystals o f

sulphate o f copper, o r has become fo u l by the depo sit o f co pperupo n the zin c plate . Whe n the last happen s, the ce llshould betaken dow n and clean ed. Whe n o n ly o n e ce ll in an o therw isego o d pile become s fo ul, and it is de sired to avo id taking do w n thepile , the foulce ll should be short-circuited

,and so put out of

action .


issue from the cable at the re ce iving end, and in crease s in strengthvery rapidly. After afurthe r in te rval o f 4aor alter aperio d of

5afrom the first applicatio n o f the batte ry, it attain s abo ut halfits maximum strength, and there is very little se nsible in crease instre ngth after atime equal to 10ahas e lapse d. The curve o f

arrival is draw n by taking distan cesalo ng 0 x (fig. 10) to represen tin te rvals of time , and distan ces alo ng 0 Y to represe n t stre ngths o f

Fig. 10.

curre n t. Curve No . I . sho w s the gradual in crease in stre ngth of

the rece ive d curren t at o n e e nd o f acable w hen the batte ry isapplied to and kept in co n tact w ith the o ther end. Fo r adistan ceco rre spo n ding to the in terval o f time athe curve do e s n o t se n siblyde viate from the straight lin e 0 x ; in o the r w ords

,n o efi

'

ect is

observable at the re ce iving e nd during this time .

If n o w , in stead o f be ing co n tinuously applied to the battery atthe sending e nd, the cable had be en applied to it during ashortin te rval o f time , and then disconn e cted from the battery and co n

n ected to earth, the curve of arrival w ould be of the form show n

THOMSON AND JENKIN’S AUTOMATIC CURB-SENDEB . 215

by curve No . II. ‘ Curve No . II . sho w s the efl‘

ect o f applyin g thebatte ry durin g

’

ale ngth o f time equal to 40,and the n pn tting the

cable to earth . It w ill be se e n thatacurren t gradually dimin ishingin st re ngth co n tin ue s to flo w out o f the cable at the distan t e nd fo raco n siderable time afte r the battery has bee n disco nn ected. Thiscon t inued discharge is w hat give s rise to the difficulty experi e n cedin r e ading the signals sen t through lo ng cables .

20. The principle of curb se nding is to check this dischargeby s e nding into the cable ase co n d curren t w hich w ill n e utralisethe bad effe cts of the first. Thus, le t the cable in stead o f be in gput. to earth afte r having be en in °

co n tact w ith o n e po le of the

batt e ry during the time 4a, be put in co n tact w ith the o ppo sitepole o f the same battery fo r an in tervalo f time equal to 3a

,and

the n be put to earth. The se co nd co n tact w ould, if it had takenPlac e alo n e , have produce d acurre n t at the distan t e nd represen te dby C urve No . III. The jo in t e ffect o f the tw o o ppo site curren tsth e first fo r an in te rval o f time 4a, and the seco nd immediate lyfollo w ing it

,and lasting fo r an in te rval o f time 3a— w ill be to

PrOduce areceived curren t repre sen ted by curve No . IV .,w ho se

o rd inate s are the algebraic sums o f the o rdinate s o f II. and III.C tlrve No . IV . thus represen ts the curve o f arrival give n by a25“g un! curren t o f duratio n 4a

,fo llo w ed by an oppo site o r curb

cin l'rent o f duratio n 3a.

§ 21. The curve o f arrival fo r any curre n t o r combinatio n o f

caI rren ts is actually trace d o n pape r by the siphon reco rde r. Sinceth e deflectio n o f the sipho n is se n sibly propo rtional to the stre ngthof the curren t at any instan t, its defle ctio n w ill corre spo nd to the(finance s measured in the directio n o f o r

,and since the pape r

moves at aun ifo rm spe e d, and in adire ctio n at right angles to thethe direction in w hich the sipho n is deflected, the distan ce s it run sw ill measure in te rvals o f time , an d w ill correspo n d to distan ce smeasured alo ng 0 x. He n ce the curve traced by the po in t o f the

The falling curve is o f exactly the same form as the curve o f arrival, and the


sipho n w ill represen t the curve o f arrival, and alltheore ticalconsideratio n s re specting the curve o farrival w ill apply equally to thepractical fo rm o f the curve draw n o n the paper slip .

The curve o f arrival, trace d according to the co n sideratio n s in19 and 20

,is the curve o f arrival in the case w here the lin e is

w o rked directly,w ithout conden sers at e ithe r end. The effe ct of

in troducing co nden sers is to co nvert w hat w as fo rmerlyaco n tin uouscurren t in to an impulse . The curve pro duced at the re ce ivin g endby the applicatio n and co n tinued co n tact ofabatte ryat the se n dinge nd

,w ould n o lo nger be o f the fo rm o f curve I. fig. 10

, but w o uldso o n reach amaximum

,after w hich it w o uld fall back to w ards the

zero lin e . It w ill be readily se e n that this w ould o f itse lf cause

Fig . 11.

Fig. 12.

something o f acurbing effect o n signals,sin ce the curve due to a

short application o f the batte ry w ould n o w come faster back to thezero lin e than formerly. This effe ct o f con den sers is partly the


fact that the curve is brought back past the zero l in e betw een th e

signals.

Fig. 12 sho w s the form o f the same letter, sen t at the same

spe ed and under the same co nditio n s, except that the signals areun curbed . In this case each o f the applicatio n s o f the batte rylasts for atime equalto 4a, and the cable is put to earth at thesending end betw een the signals for atime equal to 3a

,instead o f

having areversed curren t sen t in to it during that time . Thus inboth“ case s the to tal in te rval of time used in making each signalis 7a.

23. Such aspe ed as this (o n e signal per 7a) w ould be veryslow in the case o f alo ng cable . The actual rate o f transatlan ticsignalling is about o n e signal per 1 °5a. At this spe ed the un curbedcurve show n in fig. 12 be come s in distin ct

, and the successiveimpulse s are bare ly distingu ishable . The curbed signals, o n the

o ther han d, give acurb some w hat resembling that in fig. 12,

w here the return tow ards the cen tre or zero lin e betw e e n the

signals is o n ly partial, and n ot comple te , as in fig. 11, but i s

immen se ly greater than w hat is observed w hen un curbed signalsare sen tat the same spe ed. This greater degre e o f legibility produced by curbing e nable s the spe e d to be in creased. Experimen ts

w ith the artificial cable in the physical labo rato ry at Glasgo wappear to sho w that by using curbed signals

, and tran smittingthem automatically, as high aspe ed as o n e signal per acan easilybe attain ed o n alo ng lin e . In o the r w ords, the gain in spe ed dueto the use o f the automatic curb sende r appears to be at least fifty

per cen t.24 . In o rder that curb se nding should be succe ssful

,it is

in dispen sable that the con tacts w hich give rise to signaland curb

curren ts should be made and broke n at pe rfe ctly defin ite instants ;in o the r w o rds, pe rfe ctly co rre ct spacing is required. It has

hitherto be en found to be impo ssible to o btain this by the use of

han d keys, but it is po ssible to have perfe ctly co rre ct spacing.

bythe aid of automatic machin e ry.

The prin ciple o n w hich the automatic curb-sender w orks is asfo llo w sThe me ssage to be tran smitted is pun ched o n aslip of paper in

THOMSON AND JENKIN’S AUTOMATIC CUBB-SENDEB . 219

rightand left ho les correspo ndin g to the dash and do t o f the te legraphicalphabe t. A lin e of cen tral ho les isalso pun ched to facilitatethe draw in g alo ng of the paper. The pun ched slip is put in to thesender, an d carried along at aunifo rm rate by clo ckw ork. Whe neither aright or aleft ho le passe s under o n e o f tw o

' prickers, thecorrespo ndin g pricker descends in to the ho le , and by do ing so liftsthe end o f asprin g in to the rim of aw he e l, w hich revo lve s o n ceduring the time o ccupied in the passage o f o n e space in the pun chedpaper. The sprin g so caught remain s in the rim of the w he e lduring acomple te revo lutio n , and w hile it remain s there makesan e lectrical con n ection be tw e en the battery and ano the r se t of

Springs. The latter se t are acte d o n by adouble cam ,w hich

revo lves in the same time w ith the above-men tion ed w hee l, andby the co n tacts made during its revo lutio n sends fi rst the curren t

Fig. 14.

from on e po le o f the batte ry, and the n that fro ”

during asome w hat shorte r time , in to the c


acted o n by the pricker o n the left hand is raised, the fi rst

curren t is that from the copper po le , and the seco n d curren t thatfrom the zin c po le ; if it is the pricker on the right that has en te r e daho le in the paper, the sequen ce o f curren ts is oppo site to thatjust given . Thus an operatio n of reversal of curren ts takes placeduring the passage o f every space in the paper, but w hether th esignal curren t is to be copper and the curb curren t “zinc

,

”o r

vice versa,is dete rmin ed by w he ther the pricker has fallen into a

ho le o n the left side of the paper o r o n the right.Figs. 13, 14, and 15 , w hichare engraved fi'

om pho to graphs, givethre e gen eral view s o f the in strument. In figs. 14 and 15 , the

glass case and the standards w hich carry it have been removed,

in order to allo w the w o rks to be better se en .

25. THE DRIVING.

POWER — The mo tio n is kept up by the

descent of aw e ight, w hich has o ccasio nally to be w o und up by

hand. In o rder that the driving pow er may con tinue during thetime taken to w in d up the w e ight, the po w er is commun icawd

to the machin ery n o t dire ctly from the drum o n w hich the cordo f the w e ight is w ound, but indirectly through aspring w hich iskept in a partially w ound-up state during the descen t o f the

w e ight, and w hich give s out the en ergy so sto red up in it during

the time that the w e ight is be ing w oun d up. This secures an

approximate ly un iform driving pow er even during the w in dingup of the w e ight.The arrangemen t w ill be understo od by refe ren ce to fig. 16.

The axle A A’

w hich carrie s the Spring box S and the drum D

o n w hich the cord attached to the w e ight is w oun d, is divided at

p in to tw o parts capable of revo lving in dependen tly of o n e an o ther.A ratchet w he e l R ’

is so arranged that w hen the drum D is turn edby mean s of the handle so as to w ind up the w e ight, the part A

’

p

move s in depen den tly of A p , and during that time the machineryis driven by the spring in S. When the w e ight de sce nds, ho w ever,causing A’

p to revo lve in the oppo site dire ctio n to that of the

w inding up, the ratchet w he e l R’

n o longe r allo w s the mo tion of

A’

p to take place alon e , but make s A p be carried round w ith

A’

p . This w inds up the spring un til the force exerted by the

ten sion of the spring exceeds the resistan ce of the machinery to


sequen tly the spe ed o f tran smissio n of signals, is regulate d bymean s o f africtio n govern o r (figs. 13 and In the form o f

govern o r sho w n there is a vertical revo lving spindle , to w hichmo tio n is commun icate d by mean s of apair o f beve l w he e ls . To

the spindle is fixed acro ss bar t (fig. from each end o f w h ich aw e ight w hangs by flexible springs. As the spindle rev o lvesthese w e ights are carried ro un d w ith it, and the ir cen trifugaltende n cy causes them to pre ss again st the in side surface o f a

ring o r cylindr ical box V . This pressure cause s frictio n , andchecks the mo tio n o f the machin e . The ce n trifugalte n den cy of

the w e ights is resiste d by acouple of springs, w hich' pull them

in w ards to w ards the axis. So long as the ce n trifugal fo rce of

the revo lving w e ights is in sufficien t to overcome the te n siono f the springs and to fo rce the w e ights again st the ring

,the

go vern or do e s n o t oppo se the mo tio n o f the machin ery, w hich

therefore be come s acce lerated, un til the cen trifugal fo rce o f the

w e ights become sufficien t to bend o r exte n d the springs to such anexte n t that the w e ights rub again st the ring. The

“

frictio n so pro

duced preve nts any further in crease spe ed from takin g place .

the ten sion o n the Springs any mean s in creased, the

Fig. 16.

amoun t ce n trifugal re quired produce the distensionn e ce ssary to allow the w e ights to pressagain st the ring is in creasedalso . Hen ce the spe ed w ill be increased. Similarly, by lessening

THOMSON AND JENKIN’8 AUTOMATIC CURB-SENDER . 223

the tension o n the springs,the amo un t of cen trifugal fo rce required

to distend them is dimin ished , and the spe ed is co n seque n tly re

duced. This affords amean s o f altering the spe ed,w hich is

effected in the fo llow ing mann er. The ends of the springs w hichtendto pullin the w e ights are fixed to aco llar u w hich slide s upanddow n o n the spindle . This co llar is co nn ected by mean s o flevers to the handle T, the mo veme n t o f w hich cause s the co llar toslide up and dow n . When the co llar u is raised, the te n sio n on

the springs is in creased, and the refore the spe ed is in creased also .

When the co llar is lo w ered, the ten sio n o n the springs,and therefore the spe e d, is lessen ed.

In an o ther form o f frictio n govern or, the mo tion of the

machin ery is commun icated to the vertical spindle by mean s of

the rolling co n tact o f tw o discs at right angle s to o n e an o ther,and

the w ho le frame w o rk of the go vern o r is supported by mean s o fa

contrivan ce calle d age ometrical slide , ’ w hich e nable s it to movefreely vertically up and do w n , but in n o o ther direction . The

revolving spindle carries the w e ights,as in the fo rme r case . Whe nthe fi'amew o rk is moved up, the ho rizo n tal disc attached to therevolving spindle o f the govern or approaches the cen tre o f the

Vertical disc attached to the machin ery. Con sequen tly the latte rrotates faster re latively to the fo rmer, and the machin ery w illrevolve very fast befo re the spin dle revo lve s fast en ough to causethe w e ights to press o utw ards again st the ring. In this formOfgovern or the tensio n of the springs w hich ho ld in the w e ightsiskept unchanged, so that the rate o f revo lution o f the spindleOf the go vern or remain s co n stan t ; but the rate of revo lution o f

themachin ery re lative ly to that o f the spindle is changed by alteringthe he ight of the w ho le framew ork of the gove rn or. This is

The geometrical slide has five bearing po in ts, each o f w h ich is free to moveUpon the surface o n w hich it rests. The sixth po in t, w hich keeps the framew ork o f

the govern o r in equilibrium, is the po in t in w h ich the vertical disc is touched by thehorizontal disc. This mode o f suppo rt gives rise to aco uple tending to cause the

whole framew ork o f the govern or to revo lve about ahorizon tal axis, and th is coupleisbalanced by the momen t o f th e pressure be tween the tw o discs about the same

axis. Thus the pressure betw een th e discs is kept at aco n stan t amoun t fo r all

difieren t positio ns in to w hich the framew ork o f the go vernor may be brought for


effecte d by mean s of asuitable handle o n the right han d side of

the in strume n t. In this fo rm o f go ve rn o r afurther pro v isio n ismade fo r in creasing the range of po ssible spe ed, by alte ring thete n sio n o n the spiralsprings w hich ho ld in the w e ights. This isdo n e by mean s o f screw s in side the go ve rn o r, and attached to the sespiral springs.

27. THE STARTING AND STOPPING is effe cte d by mean s o f the

screw Y, fig. 14,o n the left-hand side o f the in strume n t

,w hich,

w hen turn ed in the dire ctio n o f the hands of aw atch , advan ce s sothat its end pre sse s again st the back o f the ve rtical beve l w he e l,w hich commun icates mo tion to the govern or. This jams the w he el,and preve n ts the machin ery from moving. When the screw is

turn ed through about half aturn in the o ther dire ctio n,the w he e l

is fre ed,and the machin e ry is fl e e to run x

28 . The revo lutio n of the machin ery effects tw o obje cts. It

carrie s o n the paper by mean s o f ato o thed ro ller o r spur w he e l,w o rking in to ace n tralro w o f ho le s in the pun ched paper

,and it

cause s aspindle to ro tate o n w hich cams are fixed,w hich make

ce rtain e le ctricalco n tacts. The to o the d ro ller w hich carrie s o n

the pape r ribbo n has sixty te e th, and it revo lve s o n ce fo r eve rysixty revo lutio n s o f the axle w hich carrie s the cams. He n ce thecams make o n e comple te revo lutio n fo r eve ry space in the paper.

The pape r has the me ssage pun ched o n it in the fo rm o f side ho le sco rre spo nding to the do t an d dash o f the alphabet, w ith aco n

tinuous ro w o f ce n tral ho le s o r inde n tatio n s w hich an sw e r the

purpo se o f ho le s. The ce n tral ho le s o r in de n tatio n s are requiredto carry the pape r o n ; the electrificale ffe cts are produced by the

0 0 0 0 0 0 0 0 0 0 0

0

Fig. 17.

side ho les o n ly. Fig . 17 sho w s the appearan ce o f apiece o f the

pun ched paper ribbo n . A space betw e e n tw o letters is fo rmedby o n e ce n tral ho le , and aspace betw e en tw o w ords by tw o

cen tral ho le s. (The spaces may also be made in an other w ay,se e


o n e of the tw o row s o f side e nd ho le s. R igidly attached to P, an dpivo te d at k, is the fo rked lever F, upo n the lo w er e nd of w hich ,i,the e nd o f the abo ve -me n tio n e d Sprin g re sts (this spring is n o t

sho w n in fig. 19 ; it is marked ain fig. 20,be low ) ; the o ther end,lo,

pre sses up again st the rim o f the cam G. The spring j tends tofo rce P dow n ; but the rim o f G preven ts Ic from risin g, and therefo re P from desce nding. The cam w he e l 0 , of w hich G is apart,make s o n e comple te revo lutio n in the time take n by the paper tomo ve o n thro ugh o n e space . Whe n a side ho le in the pape rpasse s under P

,P w o uld desce nd in to it if k w ere able to

rise . As the cam w he e l revo lve s, arece ss, m n,in the rim o f G

passe s o ver Is. At this po in t, [ais fre e to rise . Simultan e ouslyan open ing lin the rim o f 0 passe s ove r the e nd o f the springw hich rests o n i. The n , if aho le in the paper is passin g under P ,P de sce nds , i rise s, and lifts the end o f the spring through theopen ing I in to the proje cting rim o f the w he e l 0 . Whe n 72 passeso ver 10, k is depre ssed, and P rise s out of the ho le in the paper.

The spring a(fig. 20) remain s caught in the rim o f 0 un til arevo lutio n is comple ted, w he n the open ing I come s roun d again ,and allow s the spring to fall out. By this time the serie s of

operatio n s w hich makes up the signal is comple ted. The cam

w he e l has tw o sides pre cise ly alike , 0 and O'

, the o n e correspo nding to the pricker w hich stands o ver the do t ho le s, the o ther to thepricker w hich stands over the dash ho les. The e lectrical effe ctspro duced by the raising of the Springs by means of the desce n t ofthe prickers w ill be de scribed further o n .

In order that e ither pricker should descend and raise its cor

re spo nding spring in to the rim o f the cam w he e l 0 , thre eco n ditio n s must be fulfilled. lst. The Ope n ing lin the rim of

0 must be o ver the end o f the spring w hich re sts o n 73. 2nd.

The re ce ss m n in the cam G must be o ver the e nd of the

level: Is. 3rd. A ho le in the paper must be passin g un der thepricke r in questio n . By the co n structio n of the machin e

,the

first tw o o f the se co ndition s n e ce ssarily happe n togethe r ; fo r thecams O and G are rigidly fixed re lative ly to o n e an o ther

, and the

ope n ing in the o n e and the rece ss in the o ther pass the low estpo in t at the same time in the revo lutio n . The third co ndition

THOMSON AND JENKIN ’S AUTOMATIC CURB-SENDEB . 227

it in an y de sired positio n . When the in strument is prope rlyadjusted, the re cess m aw ill pass o ver I: just w hen the ce n tre o f

one o f the side ho les m the pape r is passing un der P. The n the

desce n t of the pricker, w hich begin s w hen m passe s, and its ascen t,

passage o fahole m P ,and the pricke r w ill n o t touch the edgeso f the ho le Sisi se r in falling o r in rising. This preve n ts the ho le sin the pape r i s becoming to rn o r dragge d at the edges, andadmits o f the same slip o f paperbe in g used many time s o ve r.

30, The fa w hich caries the cam w he e l 0 is sho w n in fro n t

de termin ing cam. The tw o side s o f it are insulate d from the axle

w hich are IN by the low e r ends of the forked levers i i' in tothe rim o f O U through the ope n ings lI’ w hen the co rrespo ndingprickers s s in to the ho le s in the paper. The springs a

a' and

Fig. 20.

When adash, o r right-han d side ho le ,passes, the spring ais raised in to the rim o f O, and remains there


be ing he ld up in this po sitio n . Whe n he ld up in the rim o f O

a is kept in co n tact w ith the upp er con tact sp ring d , w hile the

spring a’

remain s in co n tact w ith the lo w er co n tact spring c’

.

Similarly,ifado t ho lc had passed, aw o uld have remain e d do w n .

and in co n tact w ith c w hile a’

w o uld have be e n caught up, and

he ld up in co n tact w ith d’

. So lo ng as n o ho le in the paperpasse s

,bo th the springs aand a’ remain do w n in co n tact w ith the

lo w er co n tact springs c and c’

.

The zin c po le o f the batte ry is perman en tly co n n ected to the

lo w er co n tacts cand c’

; the coppe r po le to the uppe r co n tacts d

and d’

; w he n , the refo re , adash ho le passe s, co pper is co n n ectedto a

,an d zin c to a’

; an d w he n ado t ho le passe s, copper is co n

n ected to a’

,and zin c to a.

On the same axle w ith the de te rmin ing cam w he e l,and!

revo lving alo ng w ith it, are tw o o ther cams— I

’

and I— calledmre spe ctive ly the signaland curb cams. They are in sulated fromo n e an o the r by adisc of vulcan ite

,and are in sulate d from the-5

axle and fi om the de te rmin ing cam by the vu lcan ite tube JThey are fixed re lative ly to o n e an o the r by asmall vulcan ite—eatscre w . Fig. 21 give s a side -vie w o f the signal and curb 4

The signal cam I’

has aprojectin g edge exte nding fo r ratherzfl ir

mo re than half the circumfere nce ; the curb cam I has a pro

je cting edge w hich begin s w he re the proje ctio n o n I’ leave s ofi t ;

—7

and w hich leave s o ff w here that o n I’ begin s. Un de rn eath thesg

cams are the springs e and 6’

(fig. During rathe r mo re thar‘ :l

half the revo lu tio n the proje cting edge o f I’ depre sse s the spring

e’

,and cause s it to make co n tact w iti’

the lo w e r co n tact spring f’

, w hilfi

the spring e remain s up and in co n /

tact w ith the uppe r stud g. When)the proje cting edge o f I

’

has passed)6’

rise s, and make s co n tact w ith g’

,

w hilc simultan e ously the projectingf -Jedge o f I depre sse s e

, and ho lds it in )co n tact w ith f during the remainder/ :

o f the revo lutio n . Thus during rather‘

Fig. 21 ,

mo re than half the revo lutio n,e’

is fl


the pricker o n the left side w ould have de scen ded, and the springa

’

w ould have be en raised in to the rim o f w hile aremined

Fig. 22.

do w n . The reversal of the springs e and e’

o perated o n by thasignal and curb cams w ould have go n e o n as before . Thus duringthe passage o f 1

’

the zin c po le o f the battery w ould have be en con

n ected by w ay o f c,a,f

’

, and e’

to earth, w hile copper w o uld have :

be en co n n e cted by w ay o f d’

,a

’

, g’

and e to lin e . Similarly,during the passage o f I , coppe r w ould have be e n co n n e cted by?

"

w ay of d’

a’

, g’

,and e

’

to earth, w hile zin c w ould have be en con

n ected by w ay o f c,a, f, and e to lin e , The re w ould thus have ,

be en ap o sitive signal curren t fo llo w ed by an egative curb curre nt ;o f shorter duratio n , the jo in t effe ct o f w hich w ould have bee n to

produce a do t”signal .

The re lative lengths o f the signal and curb curren ts depenclupo n the re lative lengths o f the projecting rims of the cams 1’

and If“ Whe the r the lo nger curren t shall be po sitive and thesho rte r n egative , o r vice versa

,is de termin ed by the po sitio n o f the

springs ao r a’ in the rim o f the w he e l 0 O’

w hich is there fo recalled the determ in ing cam w he e l . Ifasuccessio n of ho le s passsesunde r e ither o f the prickers, the co rre spo n ding spring is he ld upco n tin uously in the rim o f the de te rmin ing cam w he e l un tilall

W ith regard to the proportio n w h ich the length o f the signal cam o ught to

bear to that o f the curb cam, it should be understo o d that the greater the speed ofsignalling is re lative ly to the retardation , or value of a fo r any cable , themore n early equal sh ould the signal and curb cams be . If the speed of signallingo n differen t cables be varied so as to be the same re lative ly to afor each cable , thesame pair of cams w ill be suitable forall.

231

is passing , the de sce n t o fo f the fo rked leve r to rise ,o ut o f the rim . Ifado t

simultaneously under the pricke rs, bo th thebe raised , and n o e le ctrical effects w ill be0 po le o f the batte ry w ill be disconn e cted.

oppo site to each o the r may be used to proin stead o f n o side hole .

CONTACT Pu m a— The several con tact springs, w ith

piece s and co nn ectio ns, are allfixed o n aslab o f

(figs 14 and The co n

mean s o f the screw II , w hich'

coting po in ts in the frame w o rk o f the in strumen t

aho le , aV gro o ve in lin e w ith the ho le,and a

plan e , in apiece o f me tal co nn ected to the co n tact plate (se e fig.

This mode ofsupport is called age ome trical clamp ; it hasthis advan tage , that the plate cann o t take up any o ther than o n e

cer tm'

n pontio n , an d asingle scre w is sufi cie n t to ke e p it fixed.

The springs c,c’

,d,d

’

, fandf’

are pro vided w ith brass guardbar s o r ste ps, w hich limit the ir range o f mo tio n

, and pre ven t themfro m vibrafing w hen the in strume n t is run n ing fast, o r from

sticking to and fo llo w ing the mo vin g sprin gs a,a

’

,e,and e

’

.

fi re tw o halves o f the de te rmin ing cam are insulate d from o n e

M othe r an d from the axle by vulcan ite . Each o f the fo rked leve rsw e nected to the prickers is comple te ly in sulate d . The signal andGarb cams are also in sulated from o n e an o ther and from the axle“ hence n o e le ctri cal co n tacts take place except tho se w hich havebeen co n sidered. The mode in w hich the signal , curb, and de te rmining cams are fixe d to the axle w ill be understo od by re fe rencel0 6g. 20. J is avulcanite tube to w hich the dete rm in ing cam

00’ is rigidly fixed . The brass screw K o n the right o f the de te rmining cam clamps it and the tube J on to the axle by jammingthemagain st the shoulder M . The vulcan ite scre w Qo n the leftOf the signalcam clamps it an d the curb cam o n to this tube , an dM efore to the axle also .

33. SINGLE AND DOUBLE CURE — In the forego ing descriptio n°f the e lectri cal action ,

it has be en assumed that the spring 1 w as


depresse d by the signal cam at the same in stan t that the Spr in g ao r a

’

ro se in to the rim o f the de termin ing cam . This arrangem en t

w ould give the w ho le o f the signal curre n t first, follo w ed by thew ho le o f the curb curren t

,and the revo lutio n w o uld begin w ith

the beginn ing of the former, and e nd w ith the e nd o f the latter.

A signal may, ho w ever, be produced by the jo in t actio n of m ore

than tw o curre n ts, and may repre se n t the re sultan t effect of thre eo r any n umber o f curre n ts fo llo w ing each o ther in alternate directio n s, and be ing o f diffe ren t lengths.

So long, how eve r, as the fo rm of signal and curb cams de scribedabove remain s unaltered, the re are on ly tw o o the r combinatio nspo ssible , and the se are easily obtain ed by changing the po sitio n of

the signal and curb cams re lative ly to the determin ing cam.

The arrangemen t w hich has hitherto be e n assumed to exist iscalled single curb. In it the spring c

’

is depre ssed at the in stan tthat a or a

’

rise s,and the begin n ing of the passage o f the rim of

the signal cam co in cide s w ith the begin n ing o f the signal.If the signal and curb cams are turn ed roun d o n the axle so as

to be slightly in advan ce of the de te rmin ing cam ,it is e vide n t that

w hen e ither a o r a’

rise s,the spring 6

’

w ill already have be endepre ssed for some time , and the first curren t se n t w ill be sho rterthan fo rme rly

,by an amo un t repre se n ted by the distan ce through

w hich the cams I I’ have be e n turn ed fo rw ard . The se co nd or

curb signal w ill, ho w eve r, be as lo ng as before , fo r the spring aora

’

w ill co n tinue up during the w ho le time o f the passage o f the

rim o f the curb cam . But sin ce the signal and curb cams are in

advan ce o f the de termin ing cam,the rim of the curb cam w ill all

have passed befo re the spring ao r a.’

has fallen o ut o f the rim of

the de te rmin ing cam . He n ce , befo re the signal is e n ded, the rimo f the signal cam again depre sse s the spring e

'

and se nds acurrentin to the cable o f the same name as that first sen t. This is

,how

ever, o f sho rt duratio n , for as so o n as that fraction o f the signalcam

’

s rim has passed w hich represen ts the distan ce by w hich thesignal and curb cams are in advance o f the de te rmining cam

,the

re vo lutio n w ill be comple te , the spring ao r a’

w ill drop o ut of therim o f the latter, and n o farthe r co n tacts w ill o ccur in that signal.There w ill thus have be e n thre e curre n ts produce d, the firstand


cams to pro duce three differe n t arrangeme n ts of the curren ts w hich .

go to make up asignal. A perfe ctly curbed signal— that is to

Fig. 24.

say, asignal in w hich the curve o f arrival come s rapidly do w n tothe zero lin e , and n eve r cro sse s o r leave s it— could o n ly be produced by using an infin ite serie s o f curbing curren ts alte rnate indire ctio n , and each somew hat sho rte r than its predece sso r. Of

course such an arrangeme n t is practically impo ssible . When thecurbing is n ece ssarily imperfe ct, as it alw ays is in practice , itappears that the arrangeme n t de scribed above as single curb isthe be st o f the thre e . This is aque stion w hich w ill be st be de cidedby actual trial. It appears like ly, ho w ever (indepe n de n tly o f anyco n side ratio n o f the fo rm o f the curve of arrival), that the be stmean s to pro duce asharply-defin ed signal w ould be to make use

o f the single curb arrangeme n t, thereby bringing, in the first

place,the maximum influe n ce at command to bear upo n the in di

cato r (the n e e dle o r co il, as the case may be ) to deflect it,and

the n , in the se co nd place , the maximum influen ce at comman d tocause it to return to its n ormal po sitio n— alw ays pro vided thatw ithin the limits o f asingle signal the se co n d influe n ce is in suflicien t to cause are turn much past the zero po sitio n . This lastco n ditio n can alw ays be made to ho ld go od by limiting the le ngtho f duratio n o f the curbing curren t re lative ly to the spe ed o f thesignalling.

JENKIN’S AUTOMATIC CURB-GENDER. 235

o r run CONTACT Pram — To put in the

o ff the to p o f the case and remove the fro n t

apie ce o f the pape r ribbo n . Start the

sto p it w he n apiece of the paper in w hich therepun ched is passing under the prickers. This w illi’

o f the forked le vers to lie in the irmo st depresse dslip in the plate , taking care that the springs c c’

be ing pressed against the side s of the signal andthat the ends o f the springs aa’ take up the iro n the to p o f the lo w e r en ds i t” of the forked

thre e small fe e t on the side of the frame

o ther the gro o ve , and the third pressesme tal o n the right hand sidein its pro per position , and is

to be secured there by tighten ing up the screw H.

In remo vin g the contact plate the same precaution s have to beObserved. The en ds 5 i’ o f the forked le ve rs should be depre ssedby having apie ce of unpun ched pape r under the prickers.

The platin ized co ntacts o n the vario us springs should be cleanedMuen tly. They must be kept fre e from alltraces o f o il

, and

should be frequen tly duste d w ith a came l’s-hair brush . If the

causes made are de fective o r fail , the po in ts o f co n tact should bedanced w ith avery fin e file .

Care must be taken that w he n the Springs a, a'

,c, o r e

'

rise o r

fall, they do n o t make co n tact w ith bo th the ir uppe rand the ir lo w er

eOilltact springs simultan eously.

If they did so the batte ry w ouldbe sho rt-circuite d and sparks w ould pass w hich w ould burn the

M eta. Ifany o n e o f the springs a, a’c,o r c

’

is obse rved, w he n

rising or falling, to make o n e con tact be fo re it breaks the o the r,

the guard bars w hich limit the play o f the co ntact sprin gs must begently be n t un til th is n o longe r o ccurs. N o co n tact p late s areProvided w ith each instrume n t. Whe n the instrume n t is in co n

stant use the co n tact plate s should be changed every se co nd day ,mldie o ne n o t in use sho uld be care fully clean ed befo re be ing


stan t aside ho le is passing under o n e o r o ther o f the tw o prickers.The n , taking ho ld firmly o f the vulcan ite tube J (fig. lo o senthe brass scre w K o n the right. Be care fuln o t to apply so much

fo rce as to ben d o r tw ist the axle . The cams O O’ and vu lcan ite

tube J (as w e ll as the cams I I’

) w ill the n be free to mo ve round

o n the axle . Turn them ro un d un til the cen tre o f the o pe n ings Uin the rim o f the de termin ing cam w he e l are just over the springsaa

’

. The pricke r unde r w hich the re is aho le in the pape r w illthe n be able to de scen d in to the ho le , and to raise its co rre spo n dingspring in to the rim o f the de te rmin ing cam . The ce n tre o f the

ho le in the pape r should just be passin g un der the pricker at thein stan t that the cen tre o f the ope n ing lis passing over the sprin ga.When the cams ar

e turn ed ro und in to such apo sitio n that thishappe n s, se cure them and the tube J in that po siti o n by scre w ingup K.

This adjustme n t is o f the utmo st importan ce . When signalsfail

, the cause is almo st alw ays had adjustmen t o f the de te rmin ingcam . It is difficult to judge by eye w he ther the pricke r is exactly'

o ver the cen tre o f the ho le in the pape r. When the adjustme n t :

has be en made,turn the axle slo w ly roun d by han d backw ards

and fo rw ards, and obse rve w he ther the pricke rs tear e ither the

back o r fro n t edge s o f the ho le s. If the adjustme n t is pe rfe ct,they

w ill fall in to and rise o ut o f each ho le w he n the axle is turn ede ither backw ards o r fo rw ards w itho ut touching the pape r at e itheredge o f the ho le .

38 . ADJUSTMENT OF THE SIGNAL AND CURB CAMS.

For S ingle Curb— Take ho ld o f the vulcan ite tube J firmly

w ith the right hand, and lo o sen the scre w Qw ith the left. The

signal and curb cams I’

and I w ill then be fre e to slip ro un d upo nthe tube J. Put in apiece o f pun ched pape r

,start the machin e

and stop it just w he n o n e o f the pricke rs is de sce nding in to ahole

,an d is raising its co rre spo n ding spring in to the rim o f the

dew rmin ing cam . Turn the signal an d curb cams round un til theproje cting edge o f the signal cam I’ is just depre ssing the Spring e .

The n se cure the cams in this po sitio n by tighte n ing up the scre w Q.

This adjustme n t is pe rfe ct w hen the depre ssio n o f the spring c’

is

e xactly simultan eo us w ith the rise o f the spring ao r a’. The axle


cause any check to the mo tio n o f the machin e,but as so o n as

they do pre ss again st the box,the frictio n so pro duced pre ven ts

any further in crease of spe ed. Hen ce the more tensio n there iso n the springs

, the faster w ill the machin e go .

In the se co nd fo rm,the tensio n o n the springs w hich prevent

the w e ights from diverging is n o t alte red during adjustme n t, and

co n sequen tly the maximum rate o f revo luti o n o f the gove rn orremain s con stan t ; but the w ho le frame w o rk o f the go vern o r ismoved up o r do w n so that the re lative rate s o f revo lutio n o f the

machin ery and o f the gove rn or is alte red In this formthe spe ed can be still farthe r altere d by varying the te n sio n on

the springs w hich ho ld back the w e ights. This can o n ly be do n e,ho w ever

,w hen the machin e is standing still. Care must be taken

that bo th w e ights are he ld back w ith equal fo rce , so that w henthey are caused to diverge by the revo lution o f the govern o r

,they

may bo th touch the ring at the same time , and press again st ite qually.

The box o f the govern o r must be kept clear o f dust and o il

The w e ights must n o t be allo w ed to scrape again st the bo ttom o f

the box. They can be raised by lo o se ning the screw s w hiczl1

clamp the tw o piece s o f straight spring by w hich each w e ight i s

suspen ded. These scre w s must be firmly se cured befo re tb -0

machin e is started .

No attempt should be made to vary the spe ed o f the machin e

by altering the driving w e ights. A w e ight o f about 14 lbs. w ill

ge n erally be foun d to do w e ll.Allthe bearings o f the axle s must be kept w e ll o iled. If th e

bearings are to o tight,they may be lo o sen e d by mean s o f the

bearing screw s q 9’

(fig. After lo o sen ing the nuts p p’the

scre w s can be tnrn ed e ither o ut o r in ; and w he n the de siredadjustmen t isarrived at, allchange w ill be prevented by tighte n ingup p an d p

’

. The se and the similar screw hearings o n the o theraxle s also afford the mean s of moving any o n e o f the axle s alo ngfo r asho rt distan ce in the directio n o f its length.

The in n er came of the determin ing cam w heel(G and G’

) must be

kep t w ello iled, for o therw ise the frictio n o n them o f the levers band Io

’

(fig. 19) w ill check the run n ing.

THOMSON AND JENKIN’S AUTOMATIC CURB-GENDER . 239

40.— EIE OTRIOAL CoNNECTIONs — Tbe batte ry po w e r require d

in w o rking by hand, n o t on ly be cause the curbing reduces the sizeo f the signals, butalso be cause the spe ed o f sen ding w ith the autois much greate r than w ith the hand key , and co nsequen tly themaximum deflectio n o f the co il o r n e e dle at the re ce iving end is asmalle r fractio n o f the w ho le po ssible defle ctio n .

Whe n the automatic sender is used, it is o f co urse n ece ssary toprovide ahan d key , w hich may be easily thro w n into circuit ; andfor the

‘

reaso n s just given , aseparate batte ry should be used o n thehand key o famuch smaller n umber o f cells than that use d o n the

auto . No rule can be laid do w n as to the amo un ts o f batte rypow e r. Fo r lo ng cables it w ill pro bably be fo und that tw ice asmany ce lls are require d o n the auto as o n the hand key .

In o rde r to jo in up the automatic se nde r in circuit w ith therecorder , the co n n ectio n s sho w n in figs. 8 and 9

,have o n e o r o ther

of them to be set up. A sw itch o f the fo rm sho w n in fig. 25 has

next te be pro vided. By mean s o f the leve rhandle of this sw itch

,the te rminal C can be

connecte d at w ill e ithe r t o A o r to B . The

Wire w hich leads from the se nding key to thew eerder sw itch has the n to be disattaehed fromthe sen ding key, an d attached in stead to thetaminalC o f this se co nd sw itch . The n fromBaw ire must lead to the hand key, w hich isto be pro vided w ith asuitable sen ding battery,md from A to the terminal marked L in the automatic se nder.

“he terminal E o f the auto is con n e cte d to earth, and the te rminals0and Z o f the au to are co nn ected to the copper and zin c po les o fMethm'

(and large r) sen ding batte ry. The n by simply turn in gthis sw itch over to the right the hand key w ill be thro w n in toebruit , w hile by turn ing it to the left the auto w ill be jo in ed upinstead.

The arrangeme n t o f the re co rder con n ection s sho w n in fig. 9 is

the mo st suitable fo r use w ith the automatic se nder. The auto

matic signals recorded at the sen ding station w hen that arrangement is made use of are very much mo re easily read than they are


w he n the system show n in fig. 8 is adopte d . In the latte r case thecurb, o r seco nd and re versed part o f the signal , comes o ut n earlyo r quite as prom in e ntly as the first part o r signal pro pe r. Thus thele tte r e w ill appear o n the reco rde r slip at the se n ding statio n astw o defle ctio n s, o n e abo ve an d o n e be lo w the lin e , almo st exactlyequal in amplitude

,in fo rm like the le tte r a o n the re ce ivin g slip,

and the le tter a o n the sen ding slip w ill appear like an o n the

re ce iving slip . This make s the se n t signals difficult to read ; butn o such difficulty is fe lt w hen the part o f the curren t w hich re co rdsthe Signals at the se nding statio n is allo w ed to go to earth there,as it is in the arrangemen t o f co n n e ctio n s sho w n in fig. 9. (See

41. FAILURE OF SIGNALs.— If complain tsare made that signals

se n t by the auto o ccasio nally fail to be reco rded at the re ce ivinge nd

,that do ts and dashe s are n o w and the n missed, it w ill be

n e ce ssary,lst. To lo ok at your re co rder slip

,and se e w he ther the signals

w hich are reported to have failed at the o ther e nd appear there.If they do , the n the fault must be at the o ther end, but if theydo n o t

2nd. R ead your perfo rate d slip, and se e w he ther the ho le s cor

re spo nding to the signals w hich have failed have n o t been missedin the pun ching.

3rd. If the failure s are still n o t accoun te d fo r, they must be due

to the impe rfe ct adjustme n t o f the auto , o r to bad spacing in the

pun che d pape r.

Stop the machin e w hen aho le is passing un der o n e of the

prickers,and just w hen the ope n ing lin the rim o f the deter

m in ing cam is passing o ver the springs. If n e w the pricker isfairly o ve r the cen tre o f the ho le (se e the adjustmen t isperfe ct fo r that ho le , and, if the spacing o f the ho le s in the pun chedslip is regular , the adjustme n t must be pe rfe ct fo r allho le s. In

some o f the fo rms o f pun chers abo ut to be de scribed, the spacingin the paper must be perfe ct, but in an o ther o f the fo rms it is

po ssible that the side ho le s may some time s vary slightly in po sitionre lative ly to the ce n tre ho le s. Suppo se that o n e of the side ho lesis slightly behind its proper po sitio n . The n at the in stan t that


strumen t has to be remo ved,it sho uld be take n o ff bo dily by taking

o ut the scre w s at the fo ur fe e t z z z z (fig. The vario us brasspie ce s o f the case should n o t be separated from o n e an o ther, asadifficulty w o uld probably be experien ce d in putting them togetheragain .

If it is de sired fo r any reaso n to remo ve the paper troughU

(figs. 14 and o r the pricke rs, the co n tact plate must be first

removed the n the axle w hich carries the cams should always betake n o ff. This is do n e by taking out the scre w r (fig. w hichsecure s astan dard w hich carrie s the bearings fo r the right hande nd o f the axle . Whe n the scre w r is take n o ut

,this standard

come s off,and the axle is thus easily removed w itho ut having its

bearings in terfe red w ith. The pape r trough and pickers can then

be remove d bodily by taking o ut the screw s my z y o n the righthand side -plate o f the in strumen t

,w hich se cure the an gle-pieces

carrying the trough. In this w ay the tro ugh and pricke rs can betaken o ff toge ther w itho ut any o f the small screw s be ing touchedw hich fix together the suppo rts o f the pricke rs:Care must be take n that the succe ssive turn s of the string w ound

upon the driving drum D do n o t o verlap each o the r,fo r if they (10

they are liable to come in the w ay o f the projecting spurs o n the

to o thed w he e l w hich carrie s the paper alo ng.

The string w hich suspe nds the driving w e ight must hang freely,and n o t chafe again st the sides o f the ho le in w hich it passesthro ugh the table .

PUNCHES .

43. The machin e s fo r perfo rating the paper ribbo n used in theautomatic sen de r are o f seve ral fo rms. On e pun che r is adaptedfo r pun ching side ho le s o n ly , and the paper used fo r it may beprepared befo rehand by having aprope rly spaced ro w o f centralho le s pun ched in it. This pun che r has thre e finger keys. Whenany o n e o f the thre e keys is depre ssed

,the pape r is carried along

astep. Whe n the cen tral key is depre sse d n o thing further happe n s, but w he n e ithe r o f the side keys is depre ssed aside ho le isperforated in additio n to the paper be ing moved fo rw ard. It is

e sse n tial that the paper should be at re st w hen the pun ch en ters

THOMSON AND JENKIN S AUTOMATIC CURB-SEW ER . 243

it, and sho uld co n tinue ‘at re st so lo ng as the punch is in it. The

machine is therem arranged so that the mo vemen t o f the pape rhappens early during the stroke o r depre ssio n o f the key, and the

punch is n o t fo rced thro ugh the pape r un til the e nd o f the stro ke .

The mann e r in w hich this is e ffe cted w ill be readily unde rsto o dbyan in spe ctio n o f the machin e . The fe e d mo tio n , by w hich thepaper is carried alo ng, may n o t

,ho w ever, be so readily unde rsto o d

witho ut explanation . The pape r is carried alo ng by the revo lutio nofato othed ro ller

, the te e th o f w hich e n te r the previo usly prepared cen tral ho le s. On the same axle w ith this to o thed rolle r isHatche t w hee l

,having the same n umbe r o f te e th as the re are in

the roller,so that the paper advan ce s o n e space w he n the ratche t

Wheel is pushed forw ard o n e to o th. The ratche t w hee l is causedto advance by the fo llo w ing mean s — The depressio n o f any o f

the three keys is made,by mean s o f aspring

, to communicatehorizon tal mo tio n to the pivo te d e nd o f along ho rizo n talpaul,the o ther e nd of w hich gears in to the uppe r side o f the ratche t w he e l .When the key is depressed, this pau l is pre ssed alo ng , and theratchet w he eladvan ce s. The e nd of the paulw hich gears in to it isthus carried upw ards as w e ll as alo ng , and by the time that theMehet w he e l hasadvan ce d thro ugh the space co rrespo nding to o n e

moth, the en d of the paulhas rise n so far that the back o f the paul

M es upw ards again st afirm sto p fixed abo ve it. This pre ve n tsanyfurthe radvance of the ratche t w he e l during the remainder o f

file stroke . The ho rizo n talpre ssure o n the pivo te d e nd o f the

PM] con tin ue s, how eve r,and co n seque n tly the ratchet w he e l (and

lsllm‘

efore the to o thed ro ller and the pape r) is he ld firm during thedeem t of the punch . Whe n the key is allo w ed to rise , the ho riZOutai pressure o n the paul cease s ; it is pulled backwards by aW ho spring

,and its w eight cause s the unpivo te d e nd to fall

dow n in to gear w ith the n ext te e th o f the ratche t w hee l. The

ratche t w he e l,is preve n ted from fo llo w in g the ho rizo n tal paul

backwards by aseco nd paul o r click .

In usin g this instrume nt, it is n o t e ssen tial to have pape r inwhich ace n tral ro w o f ho le s has previo usly been pun che d. If a

flip o f plain pape r he used, the to o thed ro lle r w ill make ase rie s o fe n tral embossed marks o r i nden tatio ns, w hich w illhe foun d tn

R 2


an sw er the purpo se of cen tral ho les sufiiciently w ell, fo r the paper

so prepared w ill run through the automatic se nder, the te e th in thespur w he e l o f w hich w ill e n te r the succe ssive cen tral in de n tationsin the pape r. It w ill be found n ece ssary, w hen embo sse d paper isused, to apply astro ng re tarding fo rce to the pape r as it en te rs theauto , so as to preve n t it from riding o n the top of the spurs, in steado f be ing pierced by them . This re tarding force is easily applied,in exactly the same w ay as it is applied in the sipho n re co rde r, bypassing the paper un der aspring guide , the pre ssure o f w hich

upo n the paper w ill cause frictio n and ho ld back the paper.

(Se e afig.

The depre ssio n o f the keys of this pun cher is mo st easily effectedby the help o f light w o o den malle ts

,o n the end o f w hich india

rubbe r is fixed, or, be tter still, by putting fingerstalls tippe d w ithindie -rubbe r over tw o fingers o f each han d. Care must be taken

n o t to strike asharp o r vio lent blo w , but rather to make the blow asmuch like ashove as po ssible . If the blo w be to o sharp

,the paper

w ill n o t have time to advan ce thro ugh acomplete Space befo re the

pun ch e n ters it,and

°

amisplace d o r to rn ho le w ill be producedVio len t blo w s are also ve ry apt to break the springs by w hich thefe ed mo tio n is w orked. To avo id breakage

,multiple springs are

used fo r the do t and dash keys. If the single spring un der thece n tre key should break, it is n o t n e cessary to in terrupt the w ork

to put o n an ew spring, for the space s may be made by depressingbo th side keys simultan e ously.

The bridge w hich fo rms aback stop for the keys should beadjusted so as just to touch the backs of the levers, w ithout pressing o n them, w he n theyare in the ir raised po sitio n .

44 .— THE POWER-PUNCHna— In this form o f pun cher the

heavy w o rk is do n e by po w er sto re d up in the form o f aw ound-UPspring or raised w e ight, and the o perator, by depressing the fingerkeys

,re lease s ade te n t, and so allo w s the stored-up pow e r to take

e ffect. He nce the name,in w hich the prefix po w e r has the

same sign ifican ce as it has in the te rm po w er-lo om.

”

In the po w e r-pun cher there are thre e finger keys— for the dot,dash, and space . When any o n e o f the se is depre ssed, adetentallo w s o n e te e th of an e scapement w he e l to pass. There are


le ngthe n ed by the in troductio n o f the packing pie ce . If both sidekeys are simultan e ously depre ssed

,bo th packing pie ce s are slipped

in o ve r the punche s,and allthre e ho le s are pun che d. The effect

o f this w o uld be (as w e have se e n in 31) to pro duce aspace inthe se nding.

The spring or w e ight has to be w oun d up from time totime . With an ordinary Mo rse spring

, the po w er-puncherw ill punch about tw e n ty w o rds w ithout n e eding to be w o und up

afre sh.

Great care must be taken to ke ep the fingers clear o f the keys

w hich are in te nded n o t to be depre ssed, o therw ise the packingpiece s may he slipped in acciden tallyand false signals be produced.

The be st w ay to put in the pape r is to double it ove r the end of

apie ce o f ste e l spring about six in ches lo ng,and push the spring

and pape r in together— care be ing take n to draw back the springbe fo re beginn ing to punch.

45 . THE SINGLE LEVER PUNCHER .— In this pun che r the prin

ciple o f packing piece s is used,and the fe ed mo tio n is the same as

that o f the pow er-pun cher,but the w ork is e n tire ly do n e by hand.

The re is alo ng horizo n tal lever, o n the end o f w hich n earest to

t he operato r there are thre e finger keys. Whe n any o n e o f thesekeys is depressed, the n ear e nd o f the le ver is depre sse d w ith it.Fixed to the lever is aprojectio n A (fig. w ith acam-shapedsurface , and as the lever is depressed this cam slide s alo ng thesurface o f an o ther piece B in co n tact w ith it, an d give s areciprocating mo tio n to B . The piece B actuate s the fe ed in the mannerde scribed be lo w . Whe n the ce n tre key is depre ssed the leverde sce n ds, w o rks the fe ed , and acen tre ho le is pun ched. When

e ither o f the tw o side keys is depre ssed,apacking piece slides in

o ver the top o f the co rrespo nding side punch ; then the leverde sce n ds, w orks the fe ed , and pun che s bo th aside and acentreho le . A spiral spring, fixe d to the distan t end of the lever

,pulls

it back w hen the pressure o f the fingers is remo ved.

The fe e d me chan ism show n in Fig. 26. The pape r is carriedalo ng by ato o thed ro ller C , w ho se te e th e n ter the cen tre holes.This ro ller is placed immediate ly behind the pun che s. Fixed on

the same axle as the ro ller are tw o ratchet w he e ls,D an d E

,w hose

teeth face toppo site w ays. D is the o n e by mean s o f w hich thealo ng ; the other o n e , E,

is re quired in o rder that

Fig. 26.

the paper may be he ld so as to be pe rfectly incapable o t movingduring the time that the pun ches are e n te ring and leaving it.During the early part o f the desce n t o f the lever, the pie ce Bdescends

,and carries w ith it aspring paul F, fixed o n the side o f

it neare st to the ce n tre o f the in strume n t,and gearing in to the

tlpper side o f the ratche t w he e l D. This paul pulls the ratche tWheel roun d o n e to o th , and co n se quen tly cause s the pape r to

llflvanee thro ugh o n e space . Whe n the advan ce is comple te , a

clickG,w o rking on the lo w er side o f the same ratchet w hee l, falle

into gear, and so pre ven ts the w he elfrom turn ing the w ro ng w ayduring the backstroke . Just befo re the pun ch o r pun che s e n te r

the pape r, apaul H o n the oute r side comes in to gear w ith theratche t w he elE o n its lo w e r side . This paulhas be en graduallyrising durin g the de sce n t o f the leve r, but it o n ly come s in to gearWhen the pape r is justabo ut to be punched. It remain s in duringtiimvhole time that the pun ch or pun ches are in the pape r, an dinslu'es that the paper doe s n o t move during that time . As the


leve r is allo w ed to rise , this paul falls o ut o f gear ; the paul Frise s so as to catch ho ld o f the n ext succe eding te e th o f D ,

w hilethe click G preven ts the ro ller from turn in g backw ards. The paulH is actuated by apin I projecting from the o uter side o f B .

There is aspring K pre ssing o n the back o f paul H,in o rder to

dise ngage it from the ratche t w hee l E w hen the lever rises. The reis also aspring L pressing o n the back o f B

,to make it rise w he n

the le ver rise s. The tw o springs K and L are faste n ed by scre w s

unde r the so le -plate o f the in strumen t.The surface o f the cam A is so shaped as to start the pape r

gradually , and also so as n o t to bring any force to bear upo n B

during the actual pun ching o f the pape r. The fe ed mo tio n is

comple te ly ove r befo re the punch en te rs the pape r.

The springs and pauls fo r the fe ed mo tion are usually pro videdin duplicate . Befo re attempting to take the machin e to pie ces,the operato r o ught to make sure that he unde rstan ds w hat theco nditio n s o f perfe ct w o rking are . The paul F must begin to pullroun d the ratche t D the in stan t that the lever begin s to de scend.

It must cease to pull as so o n as the paper has advan ced o n e space,and befo re the pun ch begin s to en te r the paper. At the instant

that it cease s to pull,the click G must fall into gear, and at the

same in stan t the paul H must come in to actio n . During theremain de r o f the de sce n t o f the lever, n o fo rce must be brought tobear upon B by the cam A,

altho ugh A co n tinue s moving.

ON THE USE OF A SOFT IRON CORE IN SIR WIL'

LIAM THOMSON’S MIRROR GALVANOMETERS .

In w o rking submarin e cables it is a standing rule to use th e

lo w e st batte ry po w e r po ssible that is compatible w ith the go od

w o rking o f the lin e . This rule become s o f great importan ce w horlafault make s its appearan ce . Some thre e o r fo ur years ago I w a9e ngage d in w orking alo ng cable— that from Singapo re to Ho ng

f

ko ng,w hich I be lie ve is

,e lectrically

,the lo nge st in the w o rld. To

obtain signals sufficie n tly large,w ith amoderate batte ry pow er, a

very sen sitive suspe n sio n o f the mirro r w as n ece ssary. This was


No w in the case o f first-rate in sulato rs,such as tho se o f Me ssrs.

Sho nbe rg o f Be rlin,the re sistan ce o f even the bad spe cime n s

,that

is tho se to be rejected, is oflacn very great. If the rim o f ago odinsulato r is slightly damp it w ill appear to be abad on e

, the refore

the rims o f allthe in sulato rs are artificially dried be fo re thete sting . In England the rims are dried by runn ing red ho t

ro llers alo ng the top of the in sulato r tro ugh. If the ro llers are n o tho t e n ough o r n o t kept lo ng e n o ugh over the trough the rims are

n o t dried ; if to o ho t, o r allow ed to remain to o long , the w ater

begin s to evapo rate,and o n removing the ro ller the re is fre quen tly

adepo sit o f damp o n the rim o f the in sulator. Allthis rendersquan titative in sulato r te sting ate dio us o peratio n .

No w it o ccurred to us that it m ight be po ssible mechan ically toe n large the po re s o f bad in sulato rs so as to dimin ish the ir re sistance,and so greatly to facilitate the ir dete ctio n . We sele cmd tw oin sulato rs made at Hizen in the so uth o f Japan

,o n e o f them kn own

to be go o d and the o ther bad. The re sistan ce of each in sulato r wasmeasured be fo re and after each of the fo llo w ing pro ce sse s by th e

lo ss of charge me tho d, using aThomso n’s Quadran t Ele ctromete l'

and a Co n den ser, w ho se capacity w as o n e-third of afarad,th e

e dge o f the po rce lain cups be ing in each case very carefully driedFirst. The po le s o fapo w e rfulRuhmko rfi"s co il w e re attached t o

the o utside and in side of each in sulato r in succe ssio n,an d t h e

primary curren t from aGro ve ’

s battery kept o n fo r abo ut s iX

m in ute s, the hammer o f the co il o scillating so as to make and bre i lkthe primary curren t w ith great rapidity dur ing the time . Th e

go od in sulato r w as unaffe cted, but the re sistan ce o f the bad 0 1 16

w as reduced to le ss than o n e -half.Seco ndly . Bo th in sulato rs w e re soaked fo r several days in 9

saturated so lutio n o f copper sulphate , then taken o ut and left t c

dry so as to allow the coppergulphate , by crystallizing in the por e s

o f the bad in sulato r, to en large them ; the soakingand drying w e 1 “

repeate d , and they w ere the n soaked in fre sh w ate r fo r some tim e

The go od in sulato r w as still unaffe cted ; the re sistan ce o f the bf—l d

o n e w as reduced to o n e -fo urth its o riginal value .

Thirdly. Tw o o ther in sulato rs, o n e kn o w n to be go o d au ‘d

o n e bad, afte r be ing soaked in o rdinary w ater, w ere kept at 5 1

THE POROSITY. OF DEFECTIVE INSULATORS. 251

tempe rature o f about 10° C. for fo urte e n hours by mean s of a

fre e zin g m ixture , then soake d in luke w arm w ate r fo r thre e hours,

again fro ze n and soaked in o rdinary w ater. The go od in sulato rw as unaffe cte d, the resistan ce o f the bad o n e w as reduced to o n e

third. The fo llow ing table sho w s the resistance o f the fo ur in sulators under the various circumstan ce s.

RESISTANCES IN Mne o nms.

After applicatio n After soaking inIn itial. o f Ruhmko rfi

’s Cu $0 4 an d crys After fre ezing.

co il . tallizing.

Infinite Infin ite Infin ite

Infin ite

In fin ite re sistan ce mean s that the in sulator re tain e d apo sitive01

‘

n egative charge fo r seve ralm in utes w ithout any pe rceptiblelo ss .

S in ce co n n e ctio n w ith the o utside o f the in sulato r is made byIn ean s o f acopper w ire placed in the w ater o f the tro ugh

,and

W ith the in side by acoppe r w ire attached to the iro n stalk, w e

llave tw o differen t me tals, copper and iro n , separated by the

Partially co nducting porce lain ; the in sulator, there fo re , acts as asimple ce ll, and w e are e nabled to measure its re sistan ce in tw o

distin ct w ays. By giving an indepe nden t charge from aDan ie ll’s ce ll and taking time readings w ith the e lectrome ter asthe charge is lo st

,using as the ze ro the reading w he n there is n o

filrther lo ss. Taking time readings o n in sulatio n after sho rtCircuiting

,as the in sulato r’

s o w n e lectromo tive fo rce cause s thecopper w ire attached to the iro n stalk to acquire a n egativePotential re lative to the copper w ire attached to the o utside o f the


in sulato r. In bo th case s w e must calculate the re sistan ce afte r acertain time has e lapsed

,w hen the ratio s be tw e e n succe ssive

readin gs at equal in te rvals o f time have be come equal.W e are in clin ed to think that a sudde n co o ling o f po rce lainin sulato rs from some mo derate ly high temperature

,w hich might be

de termin ed by experimen t in the manufacto ry,w o uld so e n tire ly

de stroy the in sulatio n o f bad specime n s that they might be

se parate d from the go o d w ith great faci lity. Such apro ce ss co uldmo st readily be carried o ut by the man ufacture rs. The autho rs o fthis pape r have at presen t n o oppo rtun ity o f practically te stin g ataman ufacto ry the impo rtan ce o f the ir sugge stio n . The expe ri

men ts,ho w ever, described in this commun icatio n prove con clusively

that the minute fissure s in bad in sulato rsmay be artificially en larged .

It is easy also to se e ho w the fact that bad in sulato rs act as simplevo ltaic cells may be employed in separating them from go od o n e s.

J. PERRY.

W. E. AYRTON.

The Imperial Co llege o f Engin eering,Tokei, Japan .

A NEW METHOD OF TAKING THE LOOP-TEST.

London,

October 18th , 1876.

DEAR SIB ,

Under the in structio n s o f Mr. W. F. King, Engln e er-lnChief to the We stern and Brazilian Te legraph Company, andw hile lo calising faults o n board that Company’

s repairing shipNo rseman ,

” I fo und the fo llo w ing me thod o f lo o p-te st givemore accurate re sults than any o f tho se men tio n ed in Clark andSabin e ’

s bo ok o n Electrical Table s and Formula. If yo u find that

it has n o t already be en published, pe rhaps yo u w ill kindly have itin serted in the n ext n umber o f the So cie ty

’s Journal.


as repre se n te d by fig. 2 (zinc still to w ith r, an d R, the

re sistan ce s in circuit.

”32

R ;

An d if the fault remain s co n stan tas] £2 X

311 192 Y.

Therefo re taking the mean o f o ur tw o balancings, w e ge t

7' 1+

7’

x1

jx_

It+R2

x2 Y

X. X

2R1R2

Y 2R1 R2

o r the distan ce in ohms o f the fault from that e nd o f the cabl‘ 5

marked 3 in fig. 1.

The great advan tage o f this me thod se ems to be that the samfl

amo un t of curre n t passes thro ugh the galvan ome te r as o ut at thefault.

A NEW METHOD OF TAKING THE LOOP TEST. 255

By trying quick reversals and ge tting afe w mean s, ve ry accurate re sults can be obtain ed

,o n ly the re sistan ce o f the fault Ull'n t

n o t be very high.

Yo urs faithfully, ANDREW JAMIESON .

J . S ivew rigbt, Esq . , Secretary,Society of Te legraph Engin eers.

To fi nd the diame ter 7L o faw ire to fillabobbin of give n dime nsio n s (oute r diame te r A,

in n e r diame te r a, le ngth 6) and produce agive n re sistan ce R , allo w an ce be ing made fo r the radialthickn e ss p o f the in sulating co ve ring

L e n gth o f lst co il 27r(g p

3Ao f 2nd 271'(g 3p 2

47xo f tw o to ge ther 27r(2 + 4p 2

o f n co ils 27 (n ; n2

(p 5 )

27m(3 92

N umber o f co ils 71.

To tal length o f 1 laye r

2p X

bN umber o f laye 1 s

2p )J

There fo re to tal le ngth is

Lvr b(A


therefore

therefo re

(A? 2ph )

’7r bc(A a) (A a)

there fore7r6 c A a (A a

2px 4 R

adding p9 to bo th sidesWI) 0 ASI a”)

x9 2p 7t p“ (

4 R

From w hich

o r if lo 0

w he n k is the resistan ce o f aw ire ; un its in le ngth and o n e 11

in diame ter.

[1 P] R S. BROUGH


applying the clamp, scre w ing it firmly do w n un tilthe surfaces of

the tw o halve s pre ss firmly again st o ne an o theras show n in

Fig. 3.— S1DE V IEW o r CLAMP.

Next in sert the screw s in the t op half o f the w o o d o r vu lcan it emo uld, and after they are firmly screw ed home remove the clamP ’

and the jo in t is comple te (fig.

Fig. 4.— Jomr COMPLETE.

As to the durability o f such ajo in t,

I have n o do ubt. Th e

e lectrical qualitie s, as far as I have had time to te st the sam e ?

are highly satisfactory. Te n jo in ts w ere made,in sho rt le ngths o f

o rdinary No . 7 gutta-perchaco vered w ire,by aman w ho n eve r

made agutta-perchajo in t, and immersed in w ater and te sted 0 11

NEW FORM OF JOINT FOR COVERED WIRES. 259

the fo llow ing date s by the accumulatio n te st. Batte ry o n e hundredcells. Time on e m in ute . Standard tw o yards o f the same sized

Directly afte r the te st o n March l6th the jo in ts w ere remo vedfrom the w ate r and expo se d to the atmo sphe re un til the 5th in st.w hen they w ere te sted in w ate r under precise ly the same co n

ditions,and the re sult w as iden tically the same as the third te st in

the above list. It w ill be un de rsto o d that this system o f jo in tingis n o t applicable “

to submarin e cable s un le ss in cases of emer

gency, but 18 allthat co uld be de sired fo r subterran ean an d o therWires. A box w ith allmaterials n e ce ssary fo r makin g o n e

hundred jo in ts 1n ordinary NO 7 w ire ,and sample s o f the comple tejo int, are placed o n the table for in spection .

WILLOUGHBY SMITH.

WharfRoad, City Road,May 8th , 18760


EXPERIMENTAL JOINTS RETESTED .

Accumulatio n afterMade . Material. o n e min u te ;

100 ce lls.

Jan . 13,1876 Vulcan ite

Wo od

W o od

18I3 NO. Same length

July 4th , 1876 .W . s.

NOTES ON A THUNDERSTORM WHICH PASSED OVER

CLEVEDON ,AB OUT 5 R M . ON MARCH 15TR , 1876 .

There w as butasingle flash,w hich appeared to many obse rvers to

trave l ho rizo n tally thro ugh the air. Ho w eve r the lightn ing passeddo w n the lightn ing-co nducto r o f Christchurch. The flag-staff, about

100 fe e t high , and the fo ur pin nacle s,about 90 fe e t high, have

each aco n ducto r , the flag-staff having the usual co n ical po in t, thepin nacle s having the coppe r rope attached to the ir van e s. The five

copper ro pe s un ite in side the to w er in the n e ighbourho o d o f theclo ck. Lo w e r do w n the co n ducto r passe s thro ugh aslan ting holeto the o u tside , and fo r the lo w e st 12 fe e t is e n cased in apipe . 011

aching the ground it passe s in to adry fre e sto n e chan n e l fo r about

THE PERSIAN GOVERNMENT TELEGRAPHS.

By A. HOUTUM SCHINDLER ,I nspector Gen eralof Persian Telegraphs.

The first te legraph lin e w as e re cted in Persiain 1859 fi'

om

Teheran to Sultan ieh, aplace o f little importance , abo ut 160 milesfrom Teheran

,o n the road to Tauris. The co nducto r co n sisted o f

thre e kinds o f w ire— athin copper w ire , athin iro n o n e , made at

Ispahan , and agalvan ised iro n w ire o f 25 0 millimetre s diameter,bought in Russia and w as in sulated w ith small earthenwarein sulato rs o f acylin drical shape

,made at Teheran ; the w ire was

w o und ro und each insulator . The in strumen ts w ere Breguet’

s

alphabe tical dials. This lin e w orked fo r o n ly o n e summer ; the

Shah left Sultan ieh in the autumn , and the lin e , be ing of n o

further use,w as demolished.

A lin e from Tauris to Tehe ran w as e re cted in the fo llo w ing yearHalf o f it w as 4 m illimetre s w ire , the o the r half w as less

than millimetre s. The in sulato rs w ere made at Tehe ran,of a

so rt o f po rce lain dust and earthen w are m ixed, and w ere of a

curious shape . Se e n from the side they resembled the lette r Ja nail at the top faste n ed them to the po st

,and the w ire w as

suspe nde d by the lo w e r part . These in sulato rs w ere found use less,and w ere n ext year replaced by some bought in Europe . The lin ew o rkedat in te rvals till 1869, w hen it w as replaced by Sieme n s’s lin e .

In 1863 the Teheran -Tauris lin e w as co n tinued to the Russianfro n tie r o n the Arras R iver by alin e o f 3 m illimetre s diame ter,in sulated by Fre n ch po rce lain in sulato rs. In this year embossingMorse in strumen ts w ere bo ught from FOrsterling, o f St. Pe tersburg.

In 1863 the English Governme n t also began to e re ct aline ,o f No . 5 galvan ised iro n w ire o n w o o den po les, andSieme n s’s iron-ho o ded in sulato rs, from Bushire to Teheran

,and

then ce to Khan egin o n the'

Ih1rkish fro n tier,on the road to Bagdad.

This lin e w o rked through from Bushire to Bagdad o n the 13t h

October, 1864.

In this same year tw o o ther lin e s w ere completed by the Persian

THE PERSIAN GOVERNMENT TELEGRAPHS . 263

Go vernmen t. On e w en t from Gasvin to R e sht,and w as co n structed

o fallsorts o f w ire s and in sulato rs,the remain s o f the fo rme r lin e s ;

it w o rked fo r tw o years, w as the n o n the gro un d for tw o years, andw as repaired o r rather re -ere cte d in 1869 w ith No . 5

,

w ire and Russian double-be llpo rce lain in sulato rs. It w o rks n o w .

The o ther lin e jo in ed Teheran w ith Astrabad,via' Firuzkuh

,Sari

,

an d Barfim ish . It w as at first w e ll in sulated by Fren ch in sulato rs,had strain ing-po sts w ith ratchets

,and 3 m illimetre s w ire . As it

w as n o t kept in repair it w as so o n fo r the greate r part o n the

gro un d, and n o t lo ngafte r dese rted.

In 1869 ase co n d lin e w as comme n ced be tw e en Teheran and theRussian fron tier ; it w as No . 5

,w ire

,in sulated by Russian

do uble -be ll po rce lain in sulato rs. The arrival o fMr . Sieme n s in thisco un try putastop to the w o rks, w hich had progre ssed fo radistan ceOf e ighty-five m ile s.The English Governme n t had draw n aseco n d w ire from Bushire

to Teheran and Ke rman shah in 1867,but gave up the lin e from

Te he ran to Ke rman shah an d Khan cgin in the early part o f 1870.

The Pe rsian Governmen t ro lled up o n e o f the w ire s from Tehe ranto Ke rman shah an d used it fo r o the r lin e s.

By autumn 1870 the Pe rsian Go vernme n t fin ished a lin e o f

No . 5,

w ire,o n w o oden po le s

, and Russian do uble -be llin sulato rs, from Teheran to Astrabad, viaShahrud . It w o rks w e llat pre se n t.

Sieme n s’s lin e from Teheran to Tauris and the Russian fron tie rwas open ed fo r traflic o n the 31st January, 1870. It co n sists o fthree w ires o fNo . 5 , supporte d o n iro n po le s

, and in sulated by Sieme n s’s iro n -ho o ded in sulato rs.

In 1872 abran ch lin e , jo in in g the impo rtan t tow n o f Kho i w ithTauris

,w as co n structed. The lin e w en t from Kho i to Me rend

,o n

the Indo-European Te legraph Company’

s lin e,be tw e en Tauris an d

the Russian fro n tier, and w as No . 5 w ire an d Russian double -be llinsu lato rs. It w o rks n o w .

I n 1873 bran che s w ere e re cted jo in ing Dow le tabad,the prin

cip alplace o f the Malayer district, Sultanabad, the prin cipal placeOf the

.

Irég district, and Burujird, w ith each o the r and w ithEamadan . The se bran che s are w o rking w e ll.


The English Governmen t changed its w o ode n po le s fo r iro npo sts

,and fin ished athird w ire from Bushire to Teheran in 1874.

The te legraph lin es w hich are at pre se nt existing in Pe rsiaareas fo llow s

LINES .

Tehe ran to Bushire (English Govern

men tlin e o f thre e w ire s ; o n e w ire is

re served fo r P e rsian traffic)

Teheran to Khan egin (con structed byEnglish Governmen t : han ded overto Persian Governmen t 1870)

Teheran to SummerPalace s o fH.

'

I . M .

the Shah

Gazvin to R e shtTeh eran to Julfa(Russian fro n tier) ;(co n structed by Siemen s ; thre e w ires,o n e re served fo r P ersian traffic)

Tehe ran to Shahrlid and AstrabadMerend to Kho i

Hamadan to Dowletabad, Burujird,Sultafnafba

’

d

To tallength o f lin e s

There are m ile s o f w ire w o rked by the Persian Go ve rnmen t

,mile s by the English Go vernmen t

,and 830 m ile s by

the Indo -European Te legraph Company,making agran d to tal o f

m ile s o f w ire w o rked in Pe rsia. The distan ce s are o n lyapproximate : real thro ugh m easureme n ts have hardly eve r be entaken in this co un try.

The Persian Te legraphs are he ld by the Dire ctor-Ge n eral fo r acertain sum

,w hich he an n ually pays to the Shah , an d he w orks

them at his o w n risk,profit

,o r lo ss.

The expe n diture fo r the year o f the Hejreh 1291,that is

,from

17th February,1874 , to 6th February, 1875 ,amoun ted to

ORIGINAL COMMUNICATIONS.

The batte rie s in use are principally Dan iell’s ; w e have also afewMe idinger

’s and Min otto ’

s. The higher grade signallers also dodutyas inspe ctors.

TABLE show ing Oflice s, Stafi'

, In struments, Batteries, of the ,Persian Governm

Telegraph , lst Muharrem,1298 (28th January,

Stations o n the Eng]lin e s have no gholsas the maintenancein the hands of

English Govemmem

an d of Siemens.

receive n o salary.

3*These three stations

clerk, w ho ranks assuperin tendent,o

rch

Chefs de bureau

THE PERSIAN GOVERNMENT TELEGRAPHS. 267

Beside s the staff enumerated in the table

Dire ctor-Gen eralIn spe ctor Gen eralCo ntro llersSub-Dire cto rIn specto rs and Superin te nden tsTreasurerMechan ician

which, added to the to tal number o f the staff show n in the table

,

givesagran d to tal of 287.

We have an umber o f signalle rs w ho can w o rk the three differe n tm use in our departmen t o f Mo rse adapte d to Persian

language , the Mo rse as used in European adm in istratio n s, andthe Mo rse as used in Turkey

,that is five dg

'

fi‘

eren t alphabe ts in all,

with equal facility. Thirty w o rds,o f ale ngth o f five le tters

, per

minute is about the average Spe ed.

Regardin g the number o f me ssage s se n t and rece ived n o properregisters exist at pre se n t. AllGovernme n t me ssage sare gratis and110 registe r is kept o f them se rvice me ssage s and o ther fre e m e s

sagesare also n o t registe red. On ly the paid message s are coun te d,

and they amoun t for the year to somew hat o ver te n -w o rdrates. The Go vernmen t me ssage s fo r last year I e stimate at about

ten -w o rd rate s, and the se rvice and o the r fre e me ssages toabout rate s, making altoge ther agrand to tal o fmties tran sm itte d in the in terior . The rates fo r me ssage s in the

intel’ior are francs for the first te n w ords, and 2 fran cs for

“Very additio nal te n w o rds o r part o f ten w o rds.

The average number o f in te rnatio nal me ssage s term inating andoriginating in Persiais 160 per mo n th ; the in te rnatio nal me s8age s in tran sit are coun ted in the re turn s o f the In do -EuropeanTele graph,

I may add, that the erectiono f the lin e from Shahrud to Me shedhas been comme n ced, and w ill probably be fin ished before the


LINE SHAHRUD TO Mnsn sn .

The co n struction o f this lin e w as begun o n the 23rd May and

comple ted o n the 3lst July,1876. The le ngth o f the lin e is 271

m ile s. It w as Ope n ed fo r traffic o n the 3rd August. The w ire isgalvan ized iro n w ire o f 4 m illimetre s diame te r (No . 9 ,

The po les are poplar and fir. The in sulato rs are double po rce lainbe ll, w ith screw o r w ith ho ok and nails. The lin e has e ightstatio n s

, viz . Bahme tabad (open ed during the w in te r o n ly),Me iomey, Mian dasht, Abbasabad, Mazinan , Sabzvar, Nishapl

'

lr,

and Me shted. At Sabzvar are tran slating in strume n ts. The

in strumen ts are Siemen s’

sMo rse w ith po larized re lays,but w ithout

w riter and clo ckw o rk,w ork be ing do n e by soun d.

The w o rkmen suffe red much from w ant o f w ater and from heat.Dur ing the mo n ths o f J11119 and Ju ly the heat in the plain s

,w ith a

co o l w in d blow ing,ro se to 140 and 141 degre e s Fahre nhe it

,w hile

the heat in the shade o n ce ro se to 1 12 degre e s Fahrenhe it. Greatanxiety w as fe lt o n accoun t o f the Turcoman s, w ho w ere expe ctedto attack us every day w hile w e w ere in the fo ur stage s kno w n asthe stages o f te rro r (Shahrud to Mazinan ), but n o t asingleacoman w as se en .

270 AB STRACTS AND EXTRACTS .

to the Authors o f this pape r to be so curious and improbable thatthe ir atten tio n w as

,in depe nden tly Of each o the r, attracte d to the

subject. The co nclusio n just adverte d to w as thus expre ssed insome o f the Journals During the co nversatio n w hich arose inthe Sectio n , afte r the reading o f this commun icatio n , an ew lightse emed to break upo n the members, as it se eme d to be un iversallyadmitted that it w as mathematically impo ssible , un le ss the spe edo f the ve ssel

,from w hich the cable w as payed out, co uld be almo st

in fin ite ly increased, to lay out acable in de ep w ater (say tw o mileso r mo re ), in such aw ay as n o t to require a le ngth much greaterthan that o f the actual distan ce , as from the in clin ed direction Of

the ye t sinking part o f the cable the succe ssive po rtio n s payed outmust

, w hen they reached the bo ttom,arrange themse lve s in wavy

fo lds, sin ce the actuallength is greater than the e n tire horizon taldistan ce .

” It se emed de sirable to ascertain ho w far such an ideaas that invo lved in the abo ve stateme n t w as correct, and, if correct,w hat amoun t o f slack ought to be provided to me et the w aste in

varying depths Of w ater. This w as the primary que stio n w hichthe Authors o f this Paper propo sed to t hemse lve s, and upo n w hichthey w ere each independen tly e ngaged. They subsequentlycommun icated the ir ideas to each o the r. The inquiry bran chedOff in o ther dire ctio ns, and the re sults are n o w jo in tly submitte d tothe con sideratio n o f the Membe rs Of the In stitutio n .

The fo llo w ing are the que stio n s w hich are discusse d, gen erally,in the body o f the Paper, the calculatio n s be ing, for the mo st part,give n in an Appen dixI . Is it po ssible to lay acable straight alo ng the bo ttom ,

in deepw ater, fre e from the action o f curren ts

II . If po ssible , w hat degre e of te n sion is required, in payingout, so as to lay the cable straightIII. What is the effe ct o n the cable ,as regards strain , Ofvarying(a.) The depth Of the w ater,

The spe cific gravity Of the cable , and(c.) The ve lo city Of the paying-out ve sse l ?

IV. What are the re lative ve lo citie s o f the cable and o f the

paying out ve sse l, requisite to reduce the strain , or ten sio n , to anygiven amoun t, and w hat w illbe the consequen t waste Of cable ?

SUBMERGING TELEGRAPHIC CABLES. 271

V. What is the effe ct o f curren ts and the co n sequen t w aste o f

cable ?VI. Ho w far is it n ece ssary and safe to check the ve lo city o f

paying o ut, in passing curren ts, so as to avo id, as far as po ssible ,waste Of cable ?VII. Is it safe

,and

,if so

,under w hat circumstan ce s, to sto p

the payin g out,and to attempt to haul in the cable from great

de pthsVIII . What is the effe ct o f the ve sse l pitching in aheavy sea?

IX. What are the de side ratain the paying-out apparatusX. What w ould be the e ffe ct Of floats o r re siste rs ?XI . What are the be st mean s fo r saving the cable in case o f

Fracture

XII. What is the be st mechan ical con structio n Of asubmarin etelegraphic cable ?

I .-Is IT POSSIBLE To LAY A CABLE STRAIGHT ALONG THE BOTTOM,

m DEEP WATER , FREE FROM THE ACTION OF CURRENTS ?

Ifave sse l mo ving un iformly forw ard drop,at equal in tervals Of

time,balls Of equal Size , and Of the same material

,it may be

shown , that in w ate r,and w ith amaterial o f the specific gravity Of

the Atlan tic cable , the mo tio n o f each ball vertically w ill so o nbecome un ifo rm

,and the lin e draw n through the w ho le o f the

1Mills, at any in stan t Of time , w ill be very n early astraight lin e ,

descending oblique ly from the ship to the bo ttom. Fig. 1 sho w s

ABSTRACTS AND EXTRACTS.

the fo rm Of the lin e draw n through such aserie s o f balls, droppedfrom ave sse l mo ving at the rate o f 6 fe e t per se co n d. The equa

tio n s Ofmo tio n are (Appe ndix, Problem I .)

w hich, w he n a: is large , be come s, very n early,

The ve lo city, co n sequen tly, ultimate ly become s n,w hich is a

quan tity depending o n the fo rm an d specific gravity o f the sinkingbody.

.

Although this ultimate ve lo city is o n ly attain ed at aninfin ite depth

, ye t it is rapidly approached from the beginn ing ofthe mo tio n . If asphere o f the same diame te r and spe cific gravityas the Atlan tic cable is placed in w ater, and isallo w e d to descend,it can be sho w n that in six-te n ths o fase co n d it w illhave acquiredave lo city Of 766 fe e t pe r se co nd

,o n ly differin g from its

ultimate ve lo city by o n e thre e -thousan dth part . The depth passedthrough

,in acquiring this ve locity, is n o t quite 2 fe e t, so that in

dealing w ith co n siderable depths o f w ate r the te rm inalve locitymay be assumed as the true ve locity thro ughout.From the se equatio n s the time o f descen t of a sphe re Of the

spe cific gravity and diame ter o f the Atlan tic cable , thro ughfathoms Of w ater

,is fo und to be 48 minute s ; and if the ship

is moving at the ve lo city Of 6 fe e t per se co nd, it w ould have movedfo rw ard fe e t w hilst the bo dy sank to the bo ttom ; conse

quen tly the length o f the imaginary lin e passing through the serieso f balls w o uld be fe e t. But it is eviden t that each ballw o uld sink vertically. If the n each particle o f acable fo llow edthe same law

,and n o ten sio n w as applied at the top , there w ould

be 7 fathoms o f cable paid out fo r each fathoms runby the ship , o r alo ss o f cable o f abo ut 21 pe r ce n t. It w ill bereadily se en that this lo ss w o uld increase w ith any in crease in the

274 ABSTRACTS AND EXTRACTS .

depo sited in fo lds,o r co ils

,betw e e n C and D,

and the w aste o f

cable w o uld be the differe n ce be tw e e n AOand CD divided by AC.

The fo rmulae fo r calculating the angle 8 and the w aste o f cable ,are give n in the Appendix, Problem II .

,and by mean s o f them

the fo llo w ing table s have be en calculated fo r tw o de scriptio n s o fcable . The first is the Atlan tic cable , w ith aspecific gravity of

34 89 ; the o the r is a lighte r cable , w ith aspecific grav ity o f

ATLANTIC CABLE .

V e locity of the ayin g.

o ut vesse l, in set per

seco n d .

I OInclinatio n Of the cable 0 o l o

to the horizo n90 68 37 41 44 28 45 21 47 17 31 38 1 44

Angle Of motio n W Ith , o rin clinatio n o f lin e Ofdescen t o f each particle 0 16 50 40 35 51 30 56 49 59 43 22 62 39

V e lo city Of the cable , IIi 0

fe e t per seco nd .

4 20 24 13 2 2 7 22 06 22 15 22 82 3 7 25 60

Waste per cen t. Of cable0

payed out .

100 83 50

THE LIGHT CAB LE .

V e locity o f the ayingOut vesse l, in ect

per}

I

seco nd . i

f.

h bln clinatio n O t e ca e 0 o o o

to the ho rizo n .i 19 56 1 21 1 43 5 22

Angle o f mo tio n w ith ,o r in clinatio n o f lin e

58 7 2 00 63 62 55o f de scen t Of each particle to , the vertical

V e locity Of the eshle m0 0

feet per seco nd .

m

i 11 024 10 20 9 83 12 4

Waste per cent. Of cable61 39 36

payed out .

It has been propo sed that, in o rder to lay acable safe ly in aco n siderable depth o f w ater, it should he suffered to run out freelyfrom adrum w ithout te n sio n

,w hilst the paying-out ve sse l should

be kept at the highe st po ssible Spe ed. An in spectio n o f the abovetable s sho w s w ith w hat aw aste o f cable such apro ce e ding w ouldbe atte nded ; fo r, w ith the Atlan tic cable

,and ave locity o f the

paying-o ut ve sse l o f 15 fe e t pe r se co n d,o r abo ut 10 m ile s per


hour, the w aste o f cable w ould be 41 per ce n t. With a light

cable it w ould certainly be less ; but e ven w ith the above -me ntion ed cable , having aspecific gravity Of it w ould be 18 percent. at this high spe ed o f the Ship. The abo ve formulae also givethe ve lo city o f sinking o f the cable , in avertical and ho rizo n talpositio n , in fe e t per m in ute , to be as fo llow s

Horizontal.Atlan tic -cable 30 82

Light cable 1 '404

Lastly, they give the dire ctio n o f mo tio n and ve lo city o f the

end o f the cable in case Of fracture,and so may be use ful in

estimating any propo sed mean s Of catching it under such circumstan ces.

The w aste co n seque n t o n the te n den cy to run backw ards maybe preve n te d by paying o ut the cable unde r ace rtain amoun t o f

te n sio n . This naturally leads to an exten sio n Of the same idea,an d give s rise to the in quiry befo re propo sed, w he the r it be po ssible80 to adapt the te n sio n that afo rw ard mo tio n may be give n toeach particle sufficie n t to cause the cable to lay in astraight lin ealo ng the bo ttom ,

fre e from te n sion o n the o n e han d an d frombe n ds and co ils o n the o the r.

If the cable assume s the form o f astraight lin e A B (fig.

it is evide n t that to bring it in o rde r to lie straight at the bo ttomthe po in t A must move in the dire ctio n A C, bisecting the angleBAD

,and that each po in t be tw e e n A and B must mo ve paralle l

T 2

276 ABSTRACTS AND EXTRACTS.

to A C ; that is to say, the mo tion o f every po int in the cable mu st

be in adire ction bise cting the angle fo rmed by the cable and th ehorizo n

, and this conditio n may easily be show n to be n ece s

sary w hatever be the form take n by the cable . (Appe n dix ,Problem III.)In the case of astraight lin e allthat w ould be n e cessary to

ascertain the te nsion , w ould be find w hat force w ould bring aninflexible rod A B

,into the po sitio n B 0 , again st the re sistan ce

of the w ater. But there is n o reaso n at priori for co n cluding thatthe lin e o f the cable is straight. Inde ed, alittle co n side ratio nleads to an oppo site co n clusio n ; fo r if A B is the directio n o f th e

cable sinking w ithout te n sio n , and afo rce is applie d at A,in o rde r

to compe l A to move fo rw ard so as to arrive at C w hilst it sinksto the bo ttom, it is to be expected that the top part of the cablew ill be draw n forw ard

,and assume some n ew po sitio n , such

as A’

a. Again,the te n sion in A B , un less it van ishesat B , w ill

preven t the existe n ce Of an angle at that po in t, and an o th e rcurve B’

6 w ill result. It is, the refo re , n ece ssary to ascertain theform o f the curve assumed by the cable under ten sio n , in o rde r toe stimate the re sistan ce o f the w ate r to its mo tio n ; and as thisdepe nds at any po in t upon the in clination o f the cable to th e

ho rizon at that po in t, the problem be come s somew hat complicate d.

As it is n o t ye t suppo sed to be kn ow n w hether it is po ssible to laythe cable straight w ithout some amoun t o f te nsio n at the bo ttomit is n e cessary to frame the equatio n s o n the suppo sition of such a

ten sion existin g, and by making it 0 in the finalre sult the

effe ct w ill then be kn ow n . The problem to be so lved, then , is tofind the equation to the curve A’

B'

. The simple st mode o f pro

co eding se ems to be to co n sider the cable and the Ship at re st,

and the w ate r moving,n o t ho rizon tally, n or in any on e dire ctio n

,

but in such amann er that its directio n at any po in t P bisects theangle made at P by the cable and the horizo n , and w ith ave lo cityequalto the actualve lo city Of the po in t P in that same dire ctio n .

This mode o f con sidering the question enables it to be treate dstatically as regards the fo rm Of the curve ; and the fo llo w ing arethe forces

1. Its o w n w e ight in w ater, acting vertically.


Having thus sho w n that it is quite po ssible to lay the cablestraight alo ng the bo ttom,

the Autho rs pro ce ed to in ve stigate theamount of the te nsion , w hich forms the se cond head Of the in qu iry .

II. WHAT DEGREE or TENSION IS REQUIRED IN PAYING OUT, SOAS To LAY THE CABLE STRAIGHT

The gen eral differen tial equatio n Of the te n sio n can n o t be exactlyin tegrate d ; but the suppo sitio n upo n w hich the in tegratio n has

be en effe cted is on e that W ill n o t materially influe n ce the re sult,

and in fact becomes strictly true , if the te nsion at the bo ttombe 0.

The equation is(1 co sA)

“a:

Sin A

It'

Show s that the ten sio n at any po in t is'

equal to the w e ight inw ater o f ale ngth o f cable equal to the depth o f the w ate r be lo wthat po in t

,plus the te n sio n at the bo ttom

,le ss an amo un t due to

the frictio n o f the w ater again st the cable .

The n ext heads of the inquiry are

III . WHAT IS THE EFFECT ON THE CABLE,AS REGARDS STRAIN

,o r

VARYING?

(a.) The depth Of the w ater,(b.) The spe cific gravity o f the cable , and(c.) The ve lo city of the paying-out ve sse l ?

IV . WHAT ARE THE RELATIVE VELOCITIES OF THE CABLE AND or

THE PAYING-OUT VESSEL, REQUI SITE TO REDUCE THE STRAIN,

OR TENSION , To ANY GIVEN AMOUNT,AND WHAT WILL BE THE

CONSEQUENT WASTE or CABLE ?

The se que stio n s be ing co n n ected in the ir nature, are co n sidered

together.

It is e vide n t, from the abo ve equatio n , that the te n sio n in crease s1n ifo rmly as the depth, and as the w e ight Of the cable in w ate r ;


from w hich it fo llo w s that the le ss the specific gravity o f th e cablethe less is the risk from o ve rstrain . It is further apparen t thatthe strain is dimin ished by any in crease o f the cO-eflicie n t (m

’

) of

frictio n , and it is the refore asubje ct fo r inquiry ho w far this can

be practically accomplished. This question come s properly underthe ten th head of the inquiry, and it is, therefore , laid aside forthe presen t.An o ther method o f dimin ishing the te n sio n is by in creasing thevelocity o f paying-o ut beyo nd that of the paying-o ut vesse l . The

effect Of this is investigate d in the Appendix,w here it is Show n

that if

c be the ve locity Of the cable ,1: that Of the ship , the tension

t’

m’

(—;z co s A)

aw

w assin A

from w hich the values Of t'

may be fo und fo r any values o f w , v,

and v. The se value s have be en calculated fo r tw o cables, viz .

the Atlan tic, and o n e Of aspe cific gravity Of and table sare given , Show ing fo r each the decrease o f ten sio n atte ndan t uponincreased ratio s Of the spe ed Of the cable to that o f the ship.

Th e se re sults are exhibited in figs. 4 and 5 . In fig. 4 the

Ve rtical co lumn o n the left Sho w s the ten sion of the cable In lbs.,

the numbers at the top Sho w the rate o f the paying-o ut ve sse l, and

the ratio at the e nd o f each curved lin e is that w hich the ve lo cityo f the cable bears to that o f the ve sse l. The uppe r se rie s o f curve sre fe r to the Atlan tic cable , an d the lo w er serie s to the light o n e .

In fig. 5,w hich refers to the Atlan tic cable on ly, the number at

the end Of each curve is the rate Of the ve sse l in fe e t per se co ndthe ratio at the top is that of the ve lo city o f the cable to that Ofth e ve sse l, and the n umbe rs at the left side Sho w the co rre spo ndingte llsio n . It is fo un d that the diminutio n o f te n sio n due to anin creased rate o f paying o ut is comparative ly small, un le ss thevelo city Of th e ship itse lf is co n side rable . In fact

,the decrease o f

t‘e IlSio n , arising from letting the Atlan tic cable run o ut at tw ice the8Pe ed Of the ship, is w hen the


8 8 83 8

Spe ed Of the ship is 4 fe e t per se co nd, 251 lbs.6 622

8

n n10

andat 12 feet per second the ten smn w ould be n il.

282 AB STRACTS AND EXTRACTS.

Spe ed Of the Ship is 4 fe et pe r se con d, 30lbs. 3 7 pe r cent.

6 78

8 166

10 318

n n12 546

n63 9 n7,

From this it appears that the re lief Obtain ed by this method o f

decreasing the te n sio n is, at the o rdinary ve lo city o f paying out,

very in co n siderable ; w hilst the w aste o f cable is ve ry great. It

is submitted that the true remedy fo r the evil o f great te n sio nis the employmen t Of acable Of smallSpe cific gravity. If, fo r

instance , the tw o cable s above men tion ed are taken,it is se en

that there is aremarkable differen ce in the ten sion , the lightcable having ate nsion , in fathoms, of 879 lbs. , again st

lbs. in the case of the Atlantic cable . It is further to be

Observed, that SO lo ng as the ve locity Of payin g out do e s n o t

exce ed that of the ship, n o advan tage is derived from in creasingthe Spe ed o f the Ship

,but that, o n the co n trary

,aslight in crease

o f ten sio n must re sult. The great w aste o f cable atte n dan t o n a

slight deficie ncy of ten sio n , as in dicated by the se tables, se ems to

po in t to the de sirability o f laying cable s w ith some moderateamoun t o f te n sio n at the bo ttom ; be cause it is evide n t that ave ry moderate increase in the depth Of the w ate r w ould be atte n dedw ith agreat w aste of cable . If

,fo r in stan ce

,the Ship w as mo ving

w ith avelo city Of 6 fe e t pe r se co nd, the te n sio n o n the cable,at a

depth Of fathoms,w o uld be lbs. If

,n o w , the depth

is in crease d by 100 fathoms, the in crease o f ten sio n due to thisdepth w ou ld be abo ut 190lbs. In o rder to balan ce this, the same

extrare sistan ce must e ither be applied by the breaks,o r the cable

must run o ut at ave lo city o n e -half greate r than that o f the ship,o r at 9 fe et per se cond, and co n sequen tly w ith a w aste o f 33 per

ce n t. In the case Of the light cable , aSimilar in crease o f depthw ould , if n o t re siste d by the breaks, give rise to ave lo city o f cableOf abo ut 7 fe e t per se co nd, thus in vo lving a w aste Of 16g per

cen t. o f the cable . The se table s w ill serve to acco un t fo r the

sudden in crease o f ve lo city w hich has be e n me n tio n ed in layingheavy cable s, w he n the depth Of w ater has in creased ; and theySho w how desirable it is to be prepared w ith the fulle st information


respecting .

the depth to be traversed , and to have in readin e sseficient mean s, unde r the co ntro l o f vigilan t and in te llige n tmen

, so that by aprOpe r and gradual in crease Of re sistan ce bythe breaks

,the cable may be preven ted from acqu iring any un due

V. WHAT I S THE EFFECT OF CURRENTS, AND THE CONSEQUENTWASTE OF CABLE ?

The depth to w hich the o cean curren ts extend,the ir breadth and

their ve lo city,are difficult to ascertain ; but the Authors en ter

upon this part Of the subject in the hope that the ir in vestigation swill be of practical advantage , in so far as they serve to po in t out

the danger and inutility Of attempting to check the runn ing out ofcable due to acurren t. The actio n o f curren ts upo n acableincrease s w ith the length expo sed at any momen t o f time

,and as

the exte n t o f the curren ts is much greate r ho rizo n tally thanvertically it is Obviously desirable that the cable Should trave rsethem in the Sho rtest po ssible directio n co n sisten t w ith o ther

necessary co nditio n s. In this re spect then aheavy cable is to ‘

be

preferred, as it de scends at ahigher angle ; and it is w o rthy Of

consideratio n ho w.

far it may be practicable to in crease the ve lo cityOf Sinkin g by attaching w e ights to the cable w hilst passing

acurren t. This, the Autho rs think, may be accomplishedWithout much difficulty ; but befo re giving any opin io n upo n itsdesirability they prefe r to examin e w hat w o uld be the approxiInate loss w hich acurre n t Of agive n exte n t and ve lo city might

Let figs. 6 and 7 repre se n t aground-plan and sectio n Of the

ship’

s course , A A,fig. 6

,and Of the po sitio n o f the cable

A’

B’

,fig. 7

,and le t the commen ceme n t o f the curren t be at X Y.

When the Ship move s past A’

it w ill,un le ss preve n ted

,drift w ith

the curre n t in some directio n such as A,a (fig. and the first

effect w ill be to give the sinking cable an appare n t mo tio n in acontrary direction ; but after the actio n Of the curre n t come s Upontile who le suspended po rtio n o f the cable it w ill go o n depo sitingin the altered lin e o f the ship’

s course , as if n o curren t existed .


But if the ship is kept to atrue course the action w illbe entirelydiffere n t ; and it is n o w to be co nsidered w hat w ould be the effect

o n the cable , as regards runn ing out and te nsio n . If the current

flo w s w ith such ave lo city as to move acable laterally, to adistance

repre sen ted by the lin e 0’

c”

w hilst it Sinks from A’ A” to

B’

B”

,and if the lateral re sistan ce Of the w ate r behin d XY is

n egle cted, the cable w ould come in to the po sitio n A c’

, astraightlin e alo ng the bo ttom e qualin length to A’

B’

. If,o n the other

hand,the lateral re sistan ce behind XY is very great

, the cablew ill take adirectio n approaching to AA c

’

; but Sin ce at theve lo city of any o rdinary curren t the re sistan ce w ould be small,and sin ce

,also

,the tran sitio n from still w ater to curre n t w ould be

gradual, the lin e A c’

may be take n as virtually a straight line.The distan ce to w hich acurre n t w o uld tran spo rt aparticle freelysuspe nded is that due to the ve locity Of the curren t itse lf. Sincethere is n o te n sio n at the bo ttom ,

the cable, at that depth, w ouldbe

fre e to mo ve late rally w ith the curre n t, and the w ho le cable w oult1

assume adiago nal po sitio n from some po in t at the bo tto m,suchas

c”

,to the ship at A When the Ship has arrive d at A”,

the

distance from A,due to its ve lo city w hilst the cable is Sinking, tile

286 ABSTRACTS AND EXTRACI'

S.

lin e,but acurve , it must be acate nary ; but it can n o t be acatcher:

w itho ut ten sio n at the bo ttom ; and as there is n o tensio n at thcbo ttom, con seque n tly the lin e is n o t acate nary but astraight lineThat there is n o te n sio n at the bo ttom is on e of the conditions0the pro blem ; and it is eviden t that it must be so

,be cause if thi

ve lo city of the cable exce eds, by e ver so little, the velocity of th

ship, the cable must be depo sited in fo lds,or co ils

, and co nsequentl;

w ithout ten sion .

The same reason ing w illapply to the case o f a current w hoadepth is less than the to tal depth o f the w ater ; be cause each par;ticle afte r passing through the curren t de scends through the rest 0its co urse w itho ut any further late ral defle ction , beyon d w hat is dmto the po rtio n above it in the curren t.

The re sult,that acurre n t cause s n o cate narian strain on the

cable,is an impo rtan t o n e , and remove s w hat appeared, for along

time , to the minds o f the Authors,an obje ction to light cables.

w ho se so le disadvan tage n o w appears to be co nfin ed to alittle extnw aste o n e n tering curren ts.

If,how ever

,during the passage thro ugh acurren t, the paying

o ut is stopped , o r re tarded, astrain w ill immediate ly arise , for thicable w ill the n take the cate narian form from c

”to A”. Undal

the se circumstan ce s the strain may be calculated, as sho w n in thiAppendix

,Problem VI. , and w ill be additive to the vertical strail

arising from the w e ight. A slight additio nalstrain is broughupo n acable by acurren t caused by the frictio n o f the w ater, butit is so slight that practically it may be disregarded. The methoC

o f e stimating this is give n i n the Appe ndix, Problem VII. , and theamoun t is sho w n to be qu ite insignifican t.

VI. Ho w FAB IS IT NECESSARY AND SAFE TO CHECK THE VELOCITYo r PAYING our m PASSDIG CURRENTS, so AS TO AVOID

,AS FA]

AS POSSIBLE, WASTE o n CABLE ?

Sin ce the w aste o f cable is co nfin ed to the first e n tran ce into thcurren t, it w ould se em advisable n o t to che ck it by in creasing thten sio n , fo r the amoun t lo st must

,unde r ordinary circumstance i

be ve ry in co n siderable , even w ith amuch lighter cable than tl


Atlantic cable . Fo r in stan ce,if the curren t o f the Gulf Stream is

assumed to exte nd to adepth of 200 fathoms,w hich is probably

beyond the truth, and to flo w w ith ave lo city o f 1sfe e t pe r seco nd,

and if the rate o f the paying-o ut ve sse l is 6 fe e t pe r se co nd, thewaste Of cable , o f the Spe cific gravity o f the Atlan tic cable

,w ould

notbe mo re than 28 fathoms ; an d this is, as sho w n above,in de

penden t o f the w idth o f the stream,and o nly o ccurs at the first

entrance upo n it. Again,in the case Of amuch lighter cable

,

having aspe cific gravity Of the w aste w o uld n o t be mo re than56fathoms, and this m ight be dimin ished, by attaching Sinkers, ifdesired. It is therefore

,main tain ed, that any attempt to check the

runn ing o f the cable due to acurre n t, by an increase Of ten sio n , isalike injudicio us and unn e ce ssary.

VII. IS IT SAFE, AND , IF so,UNDER WHAT CIRCUMSTANCES

,TO STOP

THE PAYING OUT,AND TO ATTEMPT TO HAUL IN THE CABLE FROM

eBEAT DEPTHS

In orde r to so lve this que stio n it is n ecessary to find the curvewhich the cable w illassume w hen the paying-o ut is stepped, and

then to calculate the te n sio n at the ve sse l. It is eviden t,that the

curve is the commo n cate nary. Le t A B (fig. 8) repre sen t thepositio n o f the cable at any momen t Of time during the payingout

,andlet the Ship and the paying o ut sto p Simultan e o usly. The

cable w hich w as in the po sitio n AB C w ill immediate ly begin to

Fig. 8 .

rise at B,and to assume acatenarian fo rm . It is Sho w n in the

Appendix, Problem VIII . that the fo llo w ing re latio n s subsist


s — x/sg — w§+ alog

w hen w, y, and s are the respective abscissa

, o rdinate , and le ngthOf the curve

,a the angle fo rmed w ith it and the surface , and a

the ten sion at the bo ttom . Having Obtain e d the value o f a, the

to tal te n sio n is equal to aw e ight o f cable o f the depth a: plus a.

The follo w ing tables have be en calculated from the Formula5 ,

Problem VIII .,to Sho w the amoun t Of strain w hich w ou ld be

brought upon the cable by astoppage o f the paying-o ut apparatus, in adepth Of w ate r o f fathoms

,an d also the le ngth

w hich must be paid out, if the Ship is stepped, in o rder to pro duceamin imum ten sio n

ATLANTIC CAB LE .

seco n d8 10

V e locity o f the ship in fe et per}Ten sio n in

i

lbo

s. when the cableout for min imumass o f stoppage ;

and distan ce to mo ve back, tobring th e cable vertical, in

LIGHT CABLE .

V elocity of the ship in fee t per} 8 10 1

Ten sio n in lbs. w hen the cable

Length in run out fo r min imumte n sion , in case o f steppageand distance to mo ve back, to I

bring the cable vertical, in

From the se table s it appears that the re sult Of astoppage of

the paying-o ut apparatus, in adepth Of fathoms,w hilst the

ve sse l w as pro ce edn at the rate of 6 fe e t pe r se co n d, w ould be tobring the fo llo w ing strain s o n the cables

ABSTRACTS AND EXTRACTS.

due to the in ertiao f the paying-o ut drums, and o f the cable upon

them . The amo un t o f this it w ould n o t be difi cult to esfim te,

kn o w ing the de tails o f the apparatus and the form an d velocityof

the w ave ; but in to this it is unn ecessary to e n ter, further than to

remark that it furn ishe san argume n t for alight and free-w orkingapparatus. It is true that the verticalrise of the ship

’s stem

w o uld, to some exte n t

,call in to actio n the cate narian strain , but

o n ly SO far as the paying-out w as influen ced by the causes just

mentio n ed. If the paying-out w as retarded, o r e ve n entirelystopped

,the o nly effe ct o n the cable w o uld be to in crease the

abscissa o f the cate nary by the amo un t due to half the height ofthe w ave , an amo un t quite in co n siderable , in pro po rtio n to thew ho le cate narian strain

,in such depths as fi'

om fathoms to

fathoms.

IX. WHAT ARE THE DESIDEBATA IN THE PAYING-OUTAPPARATUS?

With refe ren ce to the paying-o ut apparatus the Authors w ouldlimit themse lve s to the expression of an Opin io n Of w hat ought to

be its characte ristics. The prin cipalo n e is,that its in ertiashall

be as small as po ssible ; and this affords an argumen t against theview s Of tho se w ho advo cate the use Of drums, upo n w hich thecable should be co iled . An o ther suggestio n has be en to co il thecable upon ahuge tum -table ; but if e ither Of these plan s w ere

practicable it w ould stillbe liable to the Objectio n that the inertiaOf the mass w ould be SO great that the effect Of the pitching of theve sse l w ould the n be fe lt upo n the cable almo st as much as if therate o f paying-o ut w as kept strictly un ifo rm . The o n ly argutin favour Of such plan s is the preven tio n Of kinks ; but it does notappear that any difficulty aro se from this cause in the paying-outOf the Atlan tic cable . A very impo rtan t part o f the paying-0utapparatus is the break

,and its e sse n tialcharacte ristic should be the

impo ssibility o fany strain arising from it, un der any circumstancesbeyo n d that w hich is in ten tionally impo sed. N0 in crease Of

ve lo city Should produce in crease Of strain , and it is o n ly by this

co nditio n be ing rigidly adhe red to that such ope ratio n s can be

co n ducted w ith safe ty . The Autho rs urge this po in t the mo i?e

SUBMERGING TELEGRAPHIC CABLES . 291

earn estly, as they can only acco un t fo r the failure o f the late

some w ay ge t o ut o f o rde r and astrain having arisen far beyo n dthat re corded by the indicato r. The cable w as said to be run n ingout M y , the te nsio n indicate d w as unde r lbs. , and ye t it

parted, altho ugh the actual stre ngth is given as n o t less than4§ to n s. It is n o t state d w here the cable parte d, but it is theopin io n Of the Autho rs that the sto ppage o f the paying-o ut apparatus was the cause

, and n o t the co n sequen ce , o f its parting, fo rit has already be en sho w n that such asto ppage w o uld, in thisinstance , bring an ultimate strain o f 7 to n s upon the cable .

X. WHAT WOULD BE THE EFFECT o r FLOATS, OB RESISTEB S ?

Floats , buoys, and resiste rs have severally be en propo sed as amean s o f dimin ishing the risk from tensio n . The actio n of the

forme r w ould be better accomplished by using acable o f le ssspecific gravity, because then the re lief w ould n o t be partial, butw o uld be fe lt at every po in t. It has be en sho w n that the angleof sin king has n o e ffect o n the ten sio n except in so far as this ismo dified by the fi'iction Of-the w ate r, an d there fo re the mere actio nOf floats, as tending to ke ep the cable more horizo n tal , go e s fo rlittle . The ir o n ly use w o uld be to reduce , virtually, the spe cific

Re siste rs w ould act in re lief Of the te n sio n,and be equivalen t to

increasin g the co efficien t m’ in the e quatio n s. Po ssibly,it might

be practicable so to apply them as to make the te n sio n equal tozero ; but the le ngth to w hich this Paper has exte n ded do e s n o t

permit the Authors to e n te r further in to the detail of such an

The n ext questio n w hich the Autho rs have propo sed is

XI. WHAT ARE THE BEST MEANS FOR SAVING THE CABLE,IN case ,

o r FEAOTUBE

In spite o f every pre caution , and the most comple te an d w ell

Wen when the task isallbutaccomplished, resulting in delay , an d.U 2


the lo ss, probably, of the cable itse lf. A fracture may take plu c c

from some un lo oked-fo racciden t even w hen w ithin afew miles o i

the destination , and mile s of cable lie uselessly, and pe rhapsirreco verably, at the bo ttom o f the sea.

A simple and effective plan for recovering the end o f the cable

is the refo re a very importan t subject for consideratio n . The

arrangemen t about to be described appears to the Authors likelyto succe ed in se curing the end o f the cable in case o f fi-actm'

o.

It is propo sed that asecon d ve sse l shall fo llow in the wake of

the paying-out vesse l, at such adistance that it may always

be abo ut 200 fathoms above the cable . From this vesselis

to be suspended a link,thro ugh w hich the cable should pass

fre e ly. This link should be suspe nded in such amann er thatat any momen t

,upo n asignal be ing given from the paying-out

ve sse l, it might be reversed, o r caused to ro tate in averticalplane,so as to make asingle

,double , or threefo ld h itch in the cable.

By this means the further passage o f.

the cable through the linkw ould be arreste d. The link and cable are then to be low eredtothe bo ttom ,

and the follo w ing vesse l is to put abo ut, and be movedgen tly in the oppo site dire ctio n

,at such arate as to in sure the link

and the table attached to it rising vertically to the surface , w henthe link is hauled up.

This is be st illustrated by fig. 9,in w hich A and B

o rdinary po sition s o f the ve ssels, and A C D the lin e of cable , 0

be ing the link. When the link is reversed the motion of the cable

through 0 is momen tarily arrested, and the portio n of the cable

2.

x AB STRACTS AND EXTRACTS.

For greater se curity tw o o r mo re fo llo w ing vesse ls might beemployed, each carrying its check-link suspended at the depth dueto its po sitio n .

The Authors, w hilst suggesting the above plan , fre ely admitthat it is ope n to o bjectio n . Inde ed they feelstrongly that anyapparatus co nn e cted w ith the cable after it leaves the paying-outve sse l is unde sirable , as in troducing an o ther po ssible cause of

acciden t from some unfore se en derangement or unlo oked-for

n eglect.The obje ctio n s w hich o ccur to them, to the apparatus abo vede scribed, w illn o w be po in te d out, and it must be left to o thersto decide w hether they are o f sufficien t impo rtance to lead to therejectio n o f the plan . First, there is apo ssibility of the cable

fouling, e ithe r w ith the suspe nded drums o r w ith the suspen dingrope s. This may be guarded again st by cars in paying-out, so asn o t to allo w the cable to o much slack. The risk of the catchingapparatus tw isting may , the Authors think, be avo ided by the

suspen ding-rope s be ing brought up to the oppo site sides o f the

fo llo w ing-vesse l, so that any te n den cy to tw ist w ould be re sisted,o n the prin ciple o f the bifilar mode o f suspe n sio n in the to rsio nbalan ce . Se co n dly

, adanger might o ccur if akink w e n t o verboard . This

,perhaps

,might be me t by increasing the o pe n ing

thro ugh the link be tw e en the drums so as to allo w akink to pass ;but, if n o t, it do e s n o t fo llo w that afracture w ould take place.The suspen ding-rope s o f the link should be so arranged as n o t to

admit o f any co n siderable in crease o f te n sio n, and in case of foul

ing, o r o f kinks w hich could n o t pass thro ugh the apparatus, thepaying-o ut should be stopped and the link lo w ered to the bo ttom ,

the cable be ing afterw ards draw n up, as befo re de tailed , in case o f

fracture . Doubtle ss this m ight invo lve some lo ss of time , and i t

n ece ssitate s an additio nal amo un t o f pe rso nal atte n tio n ; but tlm ‘

que stio n is w he the r abe tte r mo de can be devised, and, if n o t, is tin .

po ssible lo ss of time and the extraatte n tio n compe n sate d for b:the probable safe ty o f the cable in case o f fracture ?

A diffe ren t m ethod o f catching the cable m ight, perhaps, b ‘adopted w ith success, if the cable w ere n o t to o heavy . At acertaii —d

distan ce behind the paying-o ut ve sse l,tw o small steamers migh‘ 5

SUBMERGING TELEGRAPHIC CABLES. 2.

follo w , ke e ping as n early as po ssible in the lin e ofthe sinking cable .

From each o f them might be suspe nded o n e o r mo re grapn e ls,w ith

four o r six arms, rising upw ards at an acute angle (fig.

The se grapn e ls should be suspended in the w ater at adepth alittle

Fig. 11.

belo w the sinking cable . In case o f fracture , upo n asignal fromthe paying-o ut ve sse l, the tw o smallve sse ls should at o n ce steam

at right angle s to the ir fo rmer co urse,in oppo site dire ction s

,so that

on e o f them should cro ss the lin e o f cable , w hich w ould probablybe caught and jammed in the acute angle o f the grapn e l As so o n

as this w as do n e , w hich w o uld be kn ow n by the in crease o f ten sio non the suspen ding-ro pe o f the grapn e l , this rope should be slackedout so as to avo id fracture from any undue catenarian strain . The

ship’s co urse should then be so altered as to cause the suspe ndingrope to hang vertically, w ith o n ly such te n sio n as is due to its o w n

w eight,to that of the grapn e l, and to that o f the cable be tw e en it

and the bo ttom. The hauling-in w o uld the n be pro ce eded w ith,care be ing take n alw ays to direct the ship’s co urse so that the sus

Pending-rope might hang vertically. With a light cable thisnlethod might succe ed . It w ould n o t be so certain in its actio n asthe first pro po se d me tho d, but, o n the o ther hand , it is le ss liable toobjectio n , as acause w hich might lead to fracture , from fouling,killks

, &c. The depths at w hich the grapn e ls should hang, and thedistances o f the fo llo w ing-ve sse ls, w o uld be regulate d by the


spe cific gravity o f the cable and the spe ed of the paying-out vesse l.Table sare given in the Appendix to sho w the po sitio n o f the cable

re lative ly to the follow ing-vesse ls,at the e nd of ce rtain in tervals o f

time after fracture . These Table s furthe r sho w the time aft e r

fracture w hen the end o f the cable w ould ‘ pass be n eath th e

fo llow ing-vesse l ; first, o n the suppo sition o f that vesse l co n tinuin gher course , and seco ndly, o n the suppo sitio n o f her immediate lycro ssing the lin e o f cable w he n fracture w as signalled. The seTable sare calculated from the fo rmulain the Appe n dix, Pro ble mIX. , for tw o differen t cables, and co uld o f co urse be exte n ded to

any o ther co nditio n s o f aparticular case . In stead o f suspen din gthe grapn e ls be lo w the cable it might perhaps be prefe rable to

suspen d them alittle abo ve it, and lo w er them upo n the signal o ffracture be ing given .

XII . WHAT Is THE BEST MECHANICAL CONSTRUCTION OF A

SUBMARINE TELEGRAPHIC CABLE ?

In ven turing afe w remarks upo n the co n structio n o f the cableitse lf the Autho rs beg to say that they o n ly claim for th e irOpin ion s the me rit o f be ing legitimate deductio n s from the fo re

go ing in ve stigatio n s,e n tered upo n w ithout prejudice , and fo llo w e d

o ut to the be st of the ir ability . If the in ve stigatio n s can be sho w n

to be defective in prin ciple,o r to be inapplicable

,the opin io n s base d

o n them w ill be o f comparative ly little impo rtan ce ; but o n th e

o ther hand, if the reason ing, w hich is given in the Appen dix, beco rrect, the Authors claim for the se deductio n s apo sitive practicalvalue .

The in formatio n w hich has be en published respecting the re cen t

great experimen t is but scan ty, and there is much that is con tradicto ry in the various accoun ts. The Autho rs have , the re fo re ,refrain ed from en tering in to any revie w of the published state

men ts, o r from attempting to give a reason fo r the failure ,beyo n d apassing sugge stio n , that the stoppage o f the payin g-outapparatus m ight be the cause . They w o uld

,before go ingfurthe r,

o n ly sugge st that aminute de tail o f allthe pro ce edings, and o f

the phen omenaobserved, bo th e lectricaland mechan ical, w ould


in sulating medium. The o uter casing is w ound spirally ro un d,andit is clear that the effe ct o f ten sio n must be to stre tch it, and so to

strain bo th the insulating medium and the in n er core . This ex

te n sio n is greater than that o rdinarily due to te nsio n , from the

fo llo w ing cause . In great depths o f w ate r the pressure ppo n the

cable is very co n siderable ; fo r instance , in fathoms it is

abo ut 2} to n s per square inch. No w,un der such apressure , it is

to be expected that the in sulating medium w illbe compressed.

This be ing so , the cable w ill be reduced in diameter, and the Spiralstrands o n the outside w ill adjust themse lves to the n ew diameter,and the angle of the spirals becoming more acute , the outer

she ll w ill in crease in length. The proportion of this in crease maybe calculated, as sho w n in the Appendix, Problem 11 , w hence

it appears it isvr

’

g8

n early, w here d is the originaldiameter

from cen tre to cen tre of the spiralstrands, 8 the decrease o f dia

mete r due to compre ssio n , and lthe length in w hich the strands

make an en tire turn roun d the cable . In the Atlan tic cable d is

about 0 5 o f an in ch,lis 9 in ches, and if 8 o °i of an in ch , the

in crease of length w ould be abo ut o n e -e ighte enth part of its length,and this

,it must be bo rn e in mind, is altogether indepen den t ofthe

stre tching due to te nsion .

The Autho rsare n o taw are to w hat exten t gutta-percha is com

pre ssible , n o r have they any info rmatio n re spectin g the amo un t of

stre tching o f the Atlan tic cable under a given ten sio n . Theythere fo re co n te n t themse lve s w ith po in ting out the tw o causes of

te n sio n and compressio n , as bo th re sulting in astre tchin g o f th e

outer she ll,w hilst the in sulatio n and the in n er core are n o t thué

acted o n . It is po ssible that the amoun t of such stre tching,and ité

co nsequen t strain o n the inn er part o f the cable,may n o t be of

serio us mome n t w ithin the lim its o f the te n sio n due to the layi ngo f the cable , but it must n o t be fo rgo tte n that undue strain s mayeasily be bro ught o n by any fouling or imperfect actio n of the

paying-out apparatus, and it has be en sho w n that even at arate

o f 6 fe et per se co nd such strain may easily amoun t to 7 to n s. It

is,therefo re , perhaps n o t go ing to o far to say, that this structure

o f cable may, po ssibly, have its co nducting po w er, o r its in sulatio n ,

SUBMERGING TELEGRAPHIC CABLES.299

seriously injured by the stre tchi ng of the oute r she ll, although n o

abso lute fracture may take place . From such aco n tinge ncy theother descriptio n o f cable is fre e ,and it w ould probably remain un

injured by an y amoun t of compression , o r by any te nsio n , w ithinthe limits o f its tensile fo rce .

As regards the pro tectio n given by the oute r metallic casing, ithas be en stawd that it is o nly design ed to pro tect the inn er core

frommechan icalviolence , and to confer on the cable aco nven ien tamount o f proportionate w e ight during the process of submergencc,and that w hen o nce laid at the bo ttom the rust may eat up the

externalcoat. The Authors submit,that the re can be n o practical

difficulty in pro te cting the lighter cable from mechan ical vio lence ,by giving it an o uter coating of hempen cord, as has be en proposed, and the ir inve stigatio n s have led them to the co nclusion thatthe in crease o f w e ight due to the outer casing of the o ther cable isnotan advan tage o r co n ven ien ce

,but quite the con trary, inasmuch

as it n e ce ssitate s the applicatio n o f agreatly-in creased re sistan ceOf the breaks w hilst be ing laid do w n . But

,even if w e ight is

desirable,they w ould o bserve

,that w hat they had termed the light

System admits o f its be ing made of any de sired specific gravityand if made as heavy as the Atlan tic cable it w ould still po sse ssthe advan tage of having the w ho le o f the metallic material in thecentre

,in stead of partly in the ce n tre and partly in the circum

The re lative co st of the tw o kinds of cable is also amatte r fo rconsideratio n . The Authors are info rmed that o n alight cable of

the same po w e r as the Atlan tic cable the re w o uld be asaving o f

about thirty per cen t. in first co st.

In every po in t of view w hich has fallen under the ir n o tice theAuthors fe e l boun d to give the ir de cided o pin ion in favo ur of thelight system of cable . Whe the r there are any o bjection s to it e lectrically they are n o t prepared to say ; but finding that so lo ng agoas 1853 acable of this de scription w as propo sed an d advo catedfor the expre ss purpo se of cro ssing the Atlan tic

,curiously en ough

under the very title o f The Atlan tic Te legraph,

”the Autho rs

cann o t but think that there must exist some reason unkn ow n to

them w hy acable mo re expen sive , and more difficult to manage ,


was adopted. They ven ture to hope that this Paper may be themean s of eliciting some informatio n o n the subje ct, w hich can n o t

but be in tere sting to the pro fe ssio n at large .

In n e w bringing this commun icatio n to aclo se the Autho rs

de sire to state , that, though they have referred to the Atlan tic cableand to Mr. Allan ’

s cable as types o f tw o distin ct systems o f Co n

struction , they must disclaim any inten tion of imputing carele ssn essto tho se w ho underto ok the late expe rime n t, w hich so unfo rtunate lyfailed. The magn itude of the ope ratio n remo ve s it, to agreatexte n t, beyond the pale o f previous expe rien ce , and as such , tho seengaged in it are e n titled to the sympathy of allgen erous m inds.

This they doubtle ss have rece ived, and the Autho rs trust that therew ill n o t be ascribed to them any dispo sitio n to cavil o r blam e , w henas the result o f the ir investigatio n they have fe lt themse lve s com

pelled to expre ss the opin io n fre e ly, that though the Atlan tic cableis astep in the right dire ctio n , as compared w ith the heavier cable so f former days, it ye t falls far short in me chan ical structure andin co ndition o f the light syste m.

Still less w ould the Authors be thought to de ny the practicabilityof submerging the pre sen t Atlan tic cable ; o n the co n trary

,they

have n o he sitatio n in saying,that w ith prope r pre cautio n s, and a

due atte n tio n to w hat is required in the con structio n o f the payingout apparatus, the subme rging may probably be succe ssfullyae com

plished ; but they can n o t to o earn e stly repeat the ir co nvictio n , thatw ith the pre sen t cable the succe ss o f the operatio n w ill mainlvdepe n d upo n the nature o f the paying-out machin e ry an d the

ge n eral mechan ical arrangemen ts.

The Authors hope that the fre e expressio n o f the ir o w n Opin io ns,and of the groun ds o n w hich they are based, w ill lead to alikefree expressio n o f the opin io n s and experien ce of o thers in thediscussio n that w ill probably e n sue ; and that, ho w ever impe rfectmay be the prese n t treatmen t of the subje ct

,it may co n tribute to

diffuse abetter kn o w ledge of the prin ciple s, upo n the fo llow ing outo f w hich the succe ssful re sult o f such un dertakings main ly depe nds.The Pape r is illustrated by ase rie s Of diagrams

,from w hich

28 1 to 16 are compiled and is accompan ied by the matheaticalin ve stigatio n s at le ngth, o f w hich an abstract is given in

,e Appendix.


d c: 1 d od t fl

7=an ,_0

”

no t in tegratingand co rrccting, by making a 7, w hen t a o ,

lt =23n

log , int —

v n + v

and, substituting (1) in

The equatio ns fo rasphere are similar in form, but the constantsare3 8

5217

3 3

Co r. From it appears that w hen w is large , 0 avery nearly.

PROBLEM II .

Equations of mo tio n o f abody descen ding uniformly in anthrough aresisting medium.

Fig. 12.

Le t A be aparticle of the body.

athe angle made by Aand the vertical.5 the angle made betw een the path o f the descent A B and th e vertical ADe the velo city in A B .

9 the cochicien t for the resistan ce o f the water to the un it o f length , at t.

ve locity o f 1 fo o t per seco nd.9'

the co efiicien t for friction in the un it of length at 1 fo o t per se cond.

the w e ight of A in w ater.

Then , the resistance of the water'

In B A may be reso lved in to A C at rightanglto A, w hich may be again reso lved in to tw o fo rces, viz.

Force In AD — B) sin u up ;Force in C D q v

’sin ’(a— B) cos ato left.

Also friction in A g’09cos’ (a B)

w h ich may be reso lved in tog’9’cos’ (a B) co savertically up ;

— B) sin ato the right.


Therefore , sin ce the mo tion is un iform,

W — B) sin ¢ — B) cos ¢

g o’sin ’Os— B) cosa — B) ein a

v

‘

n n a

a» . l Th e ve lo city of run ning out vertically, w ithout tensio n , is fo und by

making a= o , w hen ce v =“2.

Co r. 2 . Th e angle at w hich the cable w ould run out w ith the greatest ve locitymay be fo un d by making w (

00 8 iii ?) a maximum from w hich9

tan a= § and fiCor . 3 . B y this problem may also be found the waste of cable w hen it runs out at

see n — tu c -l- tan fl300 6

Car . 4 . A lso , the angle of mo tio n (5) o f the end, in case of fracture , may be

Waste per cent .

when ais given .

PROBLEM III .

Fig. 13.


Le t A C P R be aportio n o f the curve .

a: any abscissa.

y the correspo nding o rdinate .

s the correspon ding length o f th e curve .

a the angle w ith the ho rizo n at C .

A the angle at any o ther po int, P .

a the length o f the cable w hose w e ight in water is equal to the horizontalten sio n at A .

th e ten sion at P ,in the directio n of the curve towards R .

9 the ve lo city of the paying-out vesse l.m th e co efiicien t o f the resistan ce o f the w aterat the ve lo city v.

I

m th e co efiicien t o f frictio n at the ve lo city v.

w the w e ight in w ater o f the un it o f length .

(3 the diame ter of the cable in the same un it.Then , it may be sho w n , in order that the length AC should be laid w ithO“t

slack along th e bo ttom, that th e po in t C must mo ve in adirectio n C m bisecting

the angle formed at C w ith the ho rizon ; and this is true o f every po int in the

curve .

Therefo re the resistan ce o f the wate rmay be replacedat every po in t by aforce Ofstream acting in the directio n bisecting the angle w ith the horizo n , and w ith 3

ve locity equal to th e ve lo city o f the po in t in that directio n .

Takingany po int C,

the ve lo city in C m 2 r em

therefo re , the resistance in C m 4m sin

180

2

"

w ith i t ?

so that the resistan ce must be re so lved in to C n and n m ; the fo rmerat right angle5

to the curve , and the latter paralle l to it, and o n lyacting by frictio n .

Wh en ce

the resistance in n C 4 m sin m sin 2 ad 8

but the cable is n o t at right angle s to C m, as it formsan angle

w hich must be again re so lved intom sin 2 aco sad s vertically up

m sin3 a. d s ho rizo ntally to the left.

Again , the ve locity in the directio n on n 2 vsin“2, therefore the frictio n fo r til"

un it o f length at c m’

4 sin ‘

gw hich must be reso lved in to (for d s)

52

2

Also , the tension at P , o r t, must be reso lved into

4 m’

sin ‘sin ad 8 vertically up

4 m’

sin ‘co sad 8 ho rizo n tally to the right.

t sin A vertically up

t co s A horizo n tally to the right.


finally, that

An equatio n be tw een a; andg—g cot A, from w hich the form of the curve maybe

derived.

If m’

be n eglecte d, or made 0, 31 may be obtain ed in terms of aseries contain

ing 40 , o r

m3

a4r + 2 s — 1 a

)41 — 1

5— 1

D + l d + x

4mg

— 1

a4 r + 12 — d

(S aD 1L £

+ w

&c & c.-P C , (9)

4 82 — 1 ,

and 0= D2 — 1 .

w0 o

0

When a: infin ity, th is gives y IC w hen ce J r , or the mchnatI

on

o f the asympto te to the ho rizo n tan

When a o ,

C] ,

w hich is the equatio n to astraight line in clin ed to film

2 2

ho rizo n at an angle co s“ l~/w +2371

” 71:

W hich value might also have bee n derived from equatio nFrom this it appears, that, w hen acable is laid w itho ut ten sio n at the bo ttom,

w illde scend in astraight lin e , inclin ed at the above angle to the ho rizon .

PROBLEM IV .

Equatio n for ten sio n .

From Problem t av (a: a)

w hich , w hen a 0 , becomes

t = ¢vw


PROBLEM V .

To find the waste o f cable from currents.

It is show n that if

d the depth to w hich the curren t extends,

v the ve lo city of the curren t,

9 the ve lo city o f the sh ip ,A the angle o f inclination of the cable to the horizo n , the

waste — J ?

PROBLEM VI .

Equatio n to the curve assumed by aflexible lin e stre tched acro ssacurrent.

Fig 14.

Le t o the angle betw een the curve and the direction of the current at any

po in t P .

l the angle betw een the directio n o f the curren t and the n o rmal to th ecurve at P .

t the ten sio n at P .

a the ten sion at A .

a

f th e force o f the curren t o n an un it o f surface at right angles to i t ”

directio n .

Then , at any po in t P ,f may be reso lved in tof sin 3

3 co s 4 in th e direction o f the curren t.

f sin 90 sin I perpendicular to the current.

Also t may be re so lved in to7: co s c in the directio n o f the curren t.

t sin perpendicular to the curren t.Therefo re ,

fi'

f siu w co s d d s— t co s p z o .

— a= o


Let A B be the line o f the cable w hilst the paying out proceeds.And let A B 3 .

A X w , the depth of the wate r.

the cum

assumed by the cable after the sto ppage .

l the length of the curve A C w hen equilibrium is established.a the tension at C .

t the tension at A.

a the angle formed by the curve A C w ith the horizon at A.

— J fi — w’

But by the e quations to the catenaryl t sin a

w t (l co s a)

y t co salogco sf”

l— mn a

Equating (1) and (2)

but (3) t the refo re

8 y J P

_3 — J 8’— z

’co salog

But aand a: are given ; therefore , from this equation asmay be found, an d then

(B

y_l— co saco salog

PROBLEM IX.

To find the depth o f the cable belo w afo llow ing vessel, at any inte rval afte ’fimmm.

SUBMERGING TELEGRAPHIC CABLES . 311

Let BC be the line o f the cable paying out .B 0 , the direction of mo tion afte r fracture ,d B F the distance o f the vesse ls apart.

Then FG (1 sin A the depth before fracture ,v the ve lo city o f the endafter fracture ,as obtained fromProblem 11 ; then

t cosB the vertical component o f the ve lo city, and the depth at the end o f

t seconds w illbe

but in t’the vesse l hasmoved forward at , and decreased the distance be tw een it and

the cable by v t sin A ; therefore the depth o f,

the cable be lo w F, at the end o f t‘

,

= d sin A + t (v co s p— v sin A) .

The fo llow ing Tables have been calculated, by means o f this formula, for tw ocables,at various speeds o f paying out.

ATLANTIC CAB LE ; Ve locity of the V esse l 6 Feet per Seco nd.

Time after Fmoture

A'rLANTIC CABLE ; V e lo city of the V esse l 8 Feet per Second.

Timeafte rFracture 20,

30,

40,

50,

Co lumn A gives the time , in seconds, after fracture , w hen the end o f the cablepasses ben eath the fo llo w ing vessel, the fo llow ing vesse l co ntinuing her course .

001n B gives the time o f passing ben eath the fo llow ing vesse l, o n the suppo sition

of the vesse l being stoppedat the instant o f fracture .


LIGHT CABLE V elocity of the V esse l 6 Feet per Second.

Time afterFracture

Distance betw een3the V e ssels

Ditto

D itto

LIGHT CABLE V e locity of the V esse l 8 Feet per Second.

Time afterFracture 70'

80,

90,

Distan ce betw e enithe V esse ls

Ditto

Ditto

Ditto

LIGHT CAB LE ; V e locity o f the V esse l 10 Feet per Seco n d.

Time afterFracture

the V esse lsD itto

Ditto

Distance betw een

PROBLEM X.

To find the extension of length due to the compression o f the inn er core .

If (I the original diameter from cen tre to cen tre o f the o uter strands,3 the decrease due to compression ,

2 : the length o f the cable in w hich the stran dsmake an entire turn ,

L the length of the strandmakingan en tire turn ,

then P=Lz— ; d

and if d become s d 3, and l’the n ew value of l,

l”=L’ -7fl2 sands— gar,

Co lumn A give s the time , in secon ds, afte r fracture , w hen the end of the cablepasse s ben eath the fo llo w ing vesse l, the fo llo w ing ve sse l co n tin uing her course

Co lumn B gives the time o f passing ben eath the fo llo w ing vesse l, o n the suppositiono f the vesse l be ing stopped at the instan t Of fracture .


g r’ t ”

T = R

Hence the variation of tension is 2m, because sin (2 I ;

or 1.

From this the fo llo w ing co rresponding valuesmay be derived

2 7370,

PAYING-OUT APPARATUS. 315

LETTER from Mr. J. A. LONGRIDGE to Captain GALTON o n PAYING

OUTAPPARATUS for SUBMAR INE TELEGRAPH CABLEs.

Captain Galton , R .E. , Board of Trade .

DEAR Sm,

I send you here w ith sketch of the paying-out apparatus I

lst. To avo id the severe strain s caused by the friction o f

heavy ro tato ry machin ery w hen th e ve sse l pitches2nd. To reduce ad libitum the injurious n ormalpre ssure of

the cable upo n the paying-out machin e .

lst. This is accomplished in methods 1 and 2 by substi tuting asliding mo tio n of the cable over asurface

,the frictio n of the cable

being the re tarding force in stead of the friction of breaks ; and inthe third me tho d by so arranging the cable over revo lving drumsthat

, w hen the strain exce e ds that of the break, the cable slips

away,w itho ut in creasing the ve lo city o f ro tatio n of the machin e ry.

Byany on e of the se methods the in ertiao f the machin ery has n oeffect o n the cable .

2nd. The n o rmalpressure at any po in t is equalto the ten siondivided by the radius o f curvature . If

,n o w , w e take a cable

runn ing out w ith the ten sio n o f 30 cw t. over a5-fe e t drum,the

normalpre ssure equals 6 cw t. per lin ealfo o t, or 56 lbs per

lineal in ch ; an amoun t w hich, if the gutta-perchabe at allsoft,w ould be very like ly to injure the in sulatio n ; and suppo se that

,by

asudde n pitch of the vesse l, the in ertiaof the w hee ls caused anextrate n sio n o f 20 cw t. w hich is greatly w ithin the limits of

what might happe n , this w ould bring an extran o rmal pre ssure o n

the cable o f 38 lbs. per lin eal in ch, making alto gether 56 38

=94 lbs. per lin ealin ch. Such apre ssure,be side s the injury to

the co re w ould preven t the adoption o f a system o f sliding,

because the fri ction w ould be so great as to tear o ff the e n tirecoating.

Now the on ly means to reduce the n ormal pressure is to

316 LETTER FROM MR . J A. LONGRIDGE ON

in crease the radius o f curvature , to w hich there is a practicallimit if circular drums be used.Again , w ith circular drums the n o rmal pre ssure is greatest

w he re the cable leave s the drum, and least w here it en ters on it ;w hereas it o ught to be co n stan t thro ughout. It is thereforeeviden t that by adopting acurve of variable radius w e can obtainacon stan t pre ssure .

This is the prin ciple of the methods 1 and 2.

METHOD 1.

The curve of con stan t pressure is aspiral of w hich the equationhas be en inve stigated.

Repre se n ting this spiral by the fo llo w ing sketch, the cable w ould

en ter it at Aand leave it at B , and

the ten sio n at A Radius and curve at Aten sio n at B Radius and curve at B

Taking the radius o f curvature at B : 16 fe e t and ofA: 2 feet,

the ten sio n at A=g o f that o f B .

The length o f curve re quired depends o n the co -eflicient of

friction , and is of course greater as the latter is le ss.

The fo llo w ing table give s an example of the actio n o f such acurve , of w hich the radii are 16 fe et and 2 fe e t re spective ly.

Le t T= ten sio n at leaving the curve .

t= te n sio n at e n tering the curve .

P= n o rmalpre ssure o n the lin eal in ch o f cable o n curve .

p: n o rmalpre ssure o n a. 5-fe et drum at leaving the drum.

318 LETTER FROM MR. J. A. LONGRIDGE ON

METHOD 2.

The curve may be fo rmed by aspiral gro ove cut in acone assho w n in fig. 2. If this co n e be re ctangular the curve pomesses

the same propertie s as the curve o f e qualpressure . The cablee n ters at the small en d o f the co n e , and makes o n e , tw o , o r more

turn s round it,the n umbe r o f turn s depe nding o n the amount of

frictio n required. If the co n e be fre e to revo lve,the cable turns

it roun d and run s itse lf fre e .

If,o n the o the r han d

,it be de sire d to in crease the retarding

force,the co n e is turn ed in areve rse directio n

, and w in ds morecable on it.

The bearing o f the con e is so arrange d as to o ffer n o impedimentto the e scape o f the cable w hen required.

Thus,by this arrangeme n t

,the re tarding fo rce can be vari edat

w ill w ith the greate st ease .

The co n e also take s up much le ss space than the curve . Its

propertie s in reducing the n o rmal pre ssure and te n sio n are similarto tho se exhibited in Table 1 , given abo ve , fo r the curve . It alsoaffo rds great facilitie s for in dicating the te n sio n .

METHOD 3.

The cable is he re passed be tw e en tw o e ndle ss be lts passing rounddrums AA and BB . The standard C is fixed w hilst D is move

able , so as to tighte n up the be lts w he n re quired .

The distan ce apart o f the top and bo ttom drums can be variedatw ill. The endle ss be lts are fo rmed thus

PAYING-OUT APPARATCS . 319

and are acted on by smallrolle rs FFF, pres sing on the back o f

each,so co n n e cted that the pressure o f the tw o be lts o n the cable

and put o n again in amomen t,E is abreak-w he e l ; and F the

shaft-e nd,w hich may be con n e cte d to asmall steam-engin e fo r

Thus it w ill be see n that the cable run s out w ith the be lts at ate nsio n regulated by abreak-w he e l, and the increased strain dueto in ertiais avo ided by the cable slipping through the be lts w he nthe te n sio n exce eds that due to the frictio n impo sed by the ro lle rsFFF

,variable at w ill.

This machin e is peculiarly applicable to picking up cable s.

I remain , yours faithfully,JAMES A. LONGRIDGE.

18, Abingdo n Stree t, W estminster,

28th No vember, 1859.

822 ON CLAMOND’S THERMO-ELECTRIC BATTERY . [m m

Go vernmen t, and by the great e le ctro-plating houses ofMessieursGo upil

, Christo flc, and o the r in dustrial institutions.In 1875 M . Clamo nd re ce ived the grand medalof the Société

d’Encourageme n t pour l

’Industrie Natio nals in recogn ition of the

value o f his inventio ns.Thermo e lectric tension (and I use the w ord tensio n thro ughout thispaper in its ordinary sense , as sign ifying difference of po tential) isproduced w hen ever tw o dissimilar me tals are place d in co ntactand

heated at the ir po in t of ju nctio n , and if the coo l extremities of theme tals are co n n e cted together, e ither dire ctly or by aco nductingw ire

, w e have athermo-e le ctric curren t, w hich w ill co ntinue toflow as lo ng as the differen ce of temperature is main tain ed. The

metals usually employed to produce this effe ct are antimonyandbismuth

,as they exhibit this prope rty in avery high degree,

but o ther me tals or alloys may be used w ith equalo r greater

advan tage .

Markus, in Germany, devised in 1865 apo w erfulfo rm of bet

tery in w hich the po sitive e lemen ts w ere compo sed o f 10 partscopper, 6 zin c, and 6 n icke l, and the n egative e lemen ts o f 12 partsan timo ny, 5 zinc, and 5 bismuth . In an o ther form o f his batteryhe employed for the po sitive metal 65 parts coppe r an d 31 zinc,and fo r the n egative 12 parts o f an timony and 5 of zinc or

German silve r.

By the term po sitive I mean that apo sitive curren t passesthrough the heated jun ction fromthe o n e me tal to the o ther as infig. 1.

The terms here employed aretho se adopted by e le ctricians

,and

they are similar to tho se used in

regard to vo ltaic couple s— fo r example , that me tal (z in c) w hichcause s a po sitive curre n t to flow

through the liquid to the other

me tal is called the e lectro -positiveme tal,and similarly w ith the thermoe lectric metals. In each case thew ire attached to the po sitive metal

Fig. 1.

ON CLAMOND’S THERMO-ELECTRIC BATTERY. 323

give s an egative curren t w hen jo in e d up in external circuit, andA506 versd

‘

.

Pro fesso r Dove employed iron and platinum so ldered togethern alte rnate lengths, and the w ho le w oun d o n acylinder o f suchliam e ter as to bring allthe iron -platinum jun ctio n s o n o n e side o f

he cylin der and allthe platin um-iro n jun ction s o n the o the r.

Bun se n used copper pyrite s, o r pyro lusite w ith copper ; 10 o ftheseslem e n ts w ere equal to aDan ie ll’s ce ll . Ste fan employed sulphide)f lead and coppe r pyrite s 5 4} of the se e lemen ts w ere said to equal9. Dan iel] .Farmer in Americaused Markus me tal and German silver, but

failed to se cure ago o d perman e n t co nn e ctio n .

Pile s o f iron and German silver have be e n made , and are veryefficie n t, but it require s about 700 e lemen ts to give ate n sion of

one vo lt.Vario us o ther forms have be en devised and used by differen t

experime n ters, but almo st the o n ly praotical application o f them has hithe rtobeen that made by Nobili and Mello n i,

who employed them in the ir magn ificen texperimen ts o n radian t heat, and theystill offer by far the mo st de licate ‘mean s

ofmeasuring minute differen ce s o f temperature at presen t kn ow n — in fact the irsensibility is such that even the heat o fthe fixed stars has be en made sen sible by

The m ixture employed byM. Clamo n dconsists ofan alloy o f tw o parts o f an timony and o n e o f zin c fo r the n egativemetal, and fo r the po sitive e lemen t he employs o rdinary tin n edBheet-iro n— the curren t flo w ing through the ho t jun ctio n from the

iron to the alloy. The combination is on e o f great pow e r. Eachelement con sists o f aflat bar o f the alloy from 2 in ches to 2§inches in length and from 8ths to 1 in ch in thickn e ss. The ir fo rmis show n by fig. 3

,by w hich it w ill be se en that lo oked at in

Y 2

324 o n cmmonn ’sm sauo-

‘

m c'rmc BATTERY. [26thApril,

plan they are spindle-shaped, or broader in the middle than at

the ends.The fo llo w ing are the three sizes most generally used

IBreadth tn

The she e t tin is stamped out in the form show n in fig. 4 ; the

narro w po rtio n is then be n t in to the fo rms sho w n,in w hich state

they are ready for be ing fixed in amould . The me lte d alloy ispoured in , and before it has cooledthe mould is ope n ed and the hatsremoved w ith the lugs securely castin to them . The mould is heated

n early to the me lting po in t of the

alloy, and 10 o r 12 barsare cast eto n e time— alittle zin c is addedfrom time to time to make up for

the lo ss by vo latilization . The alloyme ltsatatemperature o fabout 800°

Fahrenhe it ; it expands co nsiderably ih co o ling. The mo re frequen tly the alloy is re cast the moreperfe ct be come s the mixture , so that old piles can be re convenedw ith advan tage and w ith little le ss beyo nd that o f the labour. The

alloy is extreme ly w eak and brittle and easily broken by agentleblo w — in fact it is scarce ly stro nger than loaf sugar.

The tin lugs are ben t in to fo rm, and the bars are arranged in

aradial man n er ro und atempo rary brass cylin der, as show n infig. 5

,athin slip o f micabe ing in se rted be tw e en the tin lug and

the alloy to preve n t co n tact except at the junctio n . The number

of radial bars varie s w ith the size o f the pile, but fo r the usual

size s e ight o r ten are employed. As fast as the bars are laid in

326 o n CLAMOND’S THERMO-EHECTRIC BATTERY. (asthma,

The pile is usually heate d by gas mixed w ith air on the Bunsen

prin ciple ; the gas is introduced at the bottom ofatube of earthen

w are , w hich is clo se d at top, and is pierced w ithan umber of smallho le s throughout its length , co rre sponding approximately in num

ber and po sitio n w ith the n umber o f elements employed. Before

e n tering this tube the gas is allow ed to mix w ith aregulated propo rtio n of air by an orifice in the supply tube , the size of w hichcan be adjusted ; the mixed gase s escape through the holes in theearthen w are tube and there burn in smallblue je ts, the annularspace be tw ee n the gas tube and the e lemen ts forming achimneyto w hich air is admitted at bo ttom , the products o f combustione scaping at the top . The w ho le arrangemen t is show n in

in fig. 6.

Fig. 6.

When the combustio n is go ing o n properly the earthenware tub0appears o f aun iform dull cherry-red co lour througho ut, and non0of the je ts should impinge o n the side o f the pile . By burn inganexce ss o f gas it is po ssible to o verheat the pile and injure the conn e ctio n o f the e lemen ts, or even to me lt the ends o f them— iafact

1876 ] ON CLAMOND’S THERMO-ELECTR IC BATTERY. 327

they require careful and in telligen t usage . When in go od w o rkthe tempe rature o f the in n e r ends of the bars is abo ut 400° Fahrenhe it, an d that o f the outer e nds about 200° Fahrenhe it.In orde r to preve n t injury from o ve rheating and to dimin ish the

consumptio n o f gas, M. Clamo nd has re cen tly in troduce d an ew

form o f combustio n chamber by w hich he obtain s ve ry greatadvan tage s.

This fo rm is sho w n in fig. 7 . The mixture o f air and gas is

burn t in aperfo rated earthenw are tube as befo re described , butinstead o f extending the w ho le he ight o f the batte ry it o nlyextends to about o n e-half o f its he ight. The earthen w are tube is

Surrounded by an iron tube of larger diame ter, w hich extendsnearly to the top o f the battery , and is open at the top— outsidethis iro n tube and at some distan ce from it are arranged theelemen ts in the usual man n er. A moveable cover fits clo se ly o ver

the top o f the pile , andachimn ey is co nn ecte d to the bo ttom of the

328 ON CLAMOND ’S THERMO-ELECTRIC BATTERY . [28th April,

pile leading off from the annular space be tw een the iro n tube andthe in terio r face s of the e leme n ts. The air en te rs at the bo ttom of

the i ro n tube,and the heate d gase s passing up the tube curl over

at the top and de sce nd o n its outside , escaping even tually by thechimn ey. The e leme n ts are heate d partly by radiatio n from the

iro n tube, and partly by the ho t gase s w hich pass o utside the tube

do w n w ards to w ards the chimn ey. By this arrangemen t n o t on lyis great e co n omy o f gas effe cted , the co n sumptio n as I am in formedbe ing reduced by o n e -half

,but the great advan tage is o btain ed

that the je ts o f gas can n ever impinge dire ctly o n the e leme n ts,andit is thus scarce ly po ssible to injure the co nn ection s by o verheating.

In the even t o f abad co nn ectio n o ccurring, it is easy to find out

the imperfect e lemen t and thro w it o ut o f use by short-circuitingit o ver w ith apiece o f w ire , and the makers have n o difficulty incutting out adefective e leme n t an d replacing it by aso und o n e .

As the pre ssure o f gas is so liable to vary, it is n e ce ssary toemploy asmallgas regulator w ith each machin e , and the kin d theyfind be st is the o rdinary dry fo rm,

such as tho se manufactured bySugg o f Oxfo rd Stree t and o thermakers. Fo r the o rdinary thermopile w ith small-sized e leme nts, the co n sumpton o f gas is in a

gen e ral w ayabout o n e fo o t o f gas pe r hour fo r each vo lt o f te n sion,and any o rdinary gas-tap w ill supply gas e n ough to heat apow erfulpile .

Coke and charcoal have also be e n employed as asource o f heat

w ith very great e co n omy an d succe ss ; in fact the re are manycoun trie s an d place s w he re gas w ould n o t be pro curable , but w herecharcoal o r coke co uld be readily o btain ed .

The ge n e ral fo rm o f the coke -pile is sho w n in figs. 8 and 9. It

co n sists o f the usual surro unding ring o f e leme n ts,w ith acast-iron

cylinde r w ithin it fo r the combustio n o f the coke , aclo sed air spaceo f tw o o r thre e in che s be ing left be tw e en the iro n and the e lements;ashort chimn ey at top carrie s o ff the pro ducts o f combustio n

,and

is provided w ith adamper to regulate the draught. The coke

pile s are some times made o f o val fo rm and o f very large size , occu

pying aspace o f 6 fe e t by 4 fe e t o r mo re . A coke -pile w ith 400large e lemen ts has ate n sio n equal to 20 Dan ie ll’s ce lls w ith an

330 ON CLAMOND’S THERMO-ELECTRIC BATTERY. [26th Ap r il,

use . I do n o t despair o f se e ing this source o f heat utilised, an dtho se w ho have in cautiously handled the copper chimn eys of tho selamps w hen burn ing w ill admit that the heat is by n o mean s inco nsiderable . Iron screen s surrounding the thermo-piles have be e nuse d w ith advan tage , and there is o n e o n the table before yo u .

The ir obje ct is to cause acurren t o f co ld air to pass o ve r th eexte rior surface s o f the e lemen ts so as to co o l them. They als opreve n t the fracture of the bars, w hich some time s take s placew hen the pile is allow ed to co o l to o rapidly . So far as I kn ow ,

the subje ct of scre en s and curren ts o f air, the use of w ater, th e

evapo ration o f mo ist surface s,and o ther mean s o f co o ling th e

externalsurface s of the bars,have as ye t be en but imperfectly

studied, and I regard the thermo -pile as be ing stillquite in its

in fan cy, n o tw ithstanding the great advan ce s already effecte d bythe skill and perseveran ce o f M. Clamond.

The te n sio n produced by Clamo nd’s thermo -e lemen ts is such that

each 20 e lemen ts may be taken as practically equal to o n e Dan ie ll’scell, o r o n e vo lt.The fo llow ing table , published by the Thermo-Electric Ge n erato r

Company, give s at on e view the size , e le ctromo tive force , in ternalre sistan ce , and co n sumption o f fue l ofthe differen t forms o f thermopile usually made by them.

Size 0

2 vdm

380

332 o n CLAMOND’S m em o-m orale sA'rm r. [seaApril,

than 25 per cen t. greater than w hen cold ; the resistance given in

the above table is that of the piles in the ir ho t state .

A thermo -pile of 144 bars is usually arranged in 18 successivelayers, each co n sisting of e ight e lemen ts, and, as some o f these aremore fully expo sed to the heat than o thers, the te nsion of the

several laye rs varies acco rdingly. The fo llo w ing is o n e amongmany measuremen ts of the differen t ten sions commen cing at thetop

— it applie s to the ordinary fo rm o f pilelst layer o f 8 bars2nd

3rd

4th

5th

6th

7th

8th

9th

loth

11th

vo lts

It is thus se e n that the low e st laye r do es n o t give half the tensiono f the middle laye rs

,and that the upper layer is also w eake r than

tho se be n eath it. Whe n the pile is first heated the upper barsgive the greate r ten sion .

The te n sio n o f the pile asaw ho le was 8 83 vo lts,and its resist

an ce w hen ho t 35 ohms.

The pile take s about o n e hour to attain its full po te n tial,as

show n by the fo llo w ing experimen t o n apile of 240 bars


Acquired tension .

5 2 vo lts10

15

20

25

30 72 5

40

50 8 80

60

70 9-50 (full ten sion )If a pile be short-circuited, the po w erfirl curren t flo w ing

through it tends to co o l the in terior jun ctio n s and to heat theexterio r o n e s, from causes w hich w ill be referred to later o n . The

result is that the temperature o f the oppo site en ds tends to be comeequalised, and the te n sio n o f the pile is temporarily lo w ered . Thusthe above pile , short-circuited by are sistan ce equal to its ow n

,

viz . 35 ohms,has its ten sion so o n reduced from 8 5 vo lts to 8 3

vo lts, o r le ss. In asimilar w ay the the rmo-pile may be po larised,as it is somew hat inaccurate ly termed, by passing the curren t from

aGrove ’s o r Dan ie ll’s battery thro ugh it, the result be ing to heat

o n e series of jun ctio n sand to co olthe alternate on e s, thus leavingthe pile in aco n dition to give out avery sen sible curren t.

The thermo-piles are so sen sitive that it is difficult to find o n e in

such astate o f e quilibrium as to give n o curren t in e ither dire ction ;if it be so the passing o f the hand in to the in terior, o r the breathingin to it, or the approach of the body, immediate ly sets up acon

siderable actio n , and w hile they are in action the effe ct o fadistan tfire o r the Ope n ing of aw in dow pro duce s asensible effect o n the irpo ten tial. It be comes importan t, therefore , w he n tw o o r mo re pile sare employed to ke ep them as far apart as po ssible and to allo wthem fre e radiatio n .

Amo ng the uses to w hich thermo -piles may be advan tage ouslyemployed is that of e lectro -depo sitio n , and they are already muchuse d fo r e le ctro-plating. The datafo r calculating the quan tity of

coppe r or silver that may be so depo sitedare furn ished by the tablealready given , remembering thatate n sion of on e volt or exeaou s

334 o n CLAMOND’S Tarmac-ELECTRIC [sethApril,

fourth ofavo lt is sufi cien t for the deposition o f copper. A batteryof 375 e lemen ts, having are sistance of 45 ohms and atension of

146 vo lts,w as fo und in practice to depo sit about 180 grain s of

copper per hour, but then the ten sion w as sufficien t to have createdasim ilar depo sit in several successive ce lls, so that n o practicalre sults have ye t be en obtain ed o r made kn o w n w hich w ould at allcompare w ith the the oreticalpo ssibilitie s of the case .

The spe cimen o f copper pro duced is o n e-half of aplate 6 inchessquare , w hich w as depo sited by 20 bars in 23 hours ; the po tentialw as half avo lt and the in ternal resistan ce 0 25 ohm ; it is verytough and exce llen t.The me chan ical pow er o btainable from these e leme nts by e lectro

magn e tic e ngin e s has n o t yet be en put to any practicaluse . It is

certain ly given o ut in‘ avery con ven ien t form,

but theo retical consideratio n s abundan tly sho w that it cann o t be regarded as ever

like ly to form an e co n omicalso urce of po w er. With aparticulare le ctro -magn etic e ngin e of o rdinary fo rm the lifting pow er of 90

large-sized bars, co n suming 10 cubic fe et of gas per hour, was

e qual to 40 lbs. raised on e fo o t high per minute . A coke-pileburn ing 2 lbs. o f coke per hour w ould, w ith this machin e , lift

lbs. o n e fo o t high per hour, at aco st of le ss than o n e halfpe nn y

,and this w ithout employing the w ho le of the ten sion at

comman d. The e le ctric light furn ished by the se batte rie s is verypo w e rful and co n stan t, but the te n sio n n e cessary to pro duce agoodlight is so co n siderable that avery large number o f e lements hasto be employed, an d I have n o t be en able to o btain any informatio n as to the ir practical use for this purpo se . I ho pe that in thediscussio n w hich may fo llo w this pape r some such information on

bo th the abo ve po in ts may be given .

At this po in t,the usual hour fo r adjo urnme n t having already

be en exce eded, it w as an n ounced that the reading o f the con cludingpo rtion o f the pape r w ould be carried over to the n ext meeting.

ass o n cm n oun's THERMO-ELECTRIC BATTERY. [11thmy,

the last meeting, I describe d the gen eralconstruction o f Clamond’s

them e-pile s, and, had time permitted, I had in te n ded to illustratethe ir acti on by making afew measuremen ts o f the piles w hile in

w ork. As the po stpon emen t to this even ing gives us alittle moretime , I n o w propo se to review some ofthe prin cipalfacts conneded

w ith them e -e le ctricity, and I hope it w illn o t be foun d uninstructive if I illustrate some o f the prin cipalphenome naby actualexperimen t.Seebeck w as, I believe , the first to

'

o bserve the thermo-electricactio n in 1821 or 1822. The apparatus he used was almost

iden tical w ith the o n e yo u n o w see o n the table .

It co n sisted of tw o differen t me tals, antimony and bismuth beingfound the mo st effe ctive , so ldered at the ir extremities, so as to formare ctangular frame , w ithin w hich w as suspen ded amagnetisedn eedle as so o n as e ither jun ctio n w as heate d acurren t was pro

duced through the bars, and the n e edle tended to stand at rightangle s to the bars.

Pro fe ssor Cumming made avery careful investigati on of the

phen ome na, and succeeded in o btain ing magn etic ro tatio n bymeanso f the curren t.

I have here apiece o f iro n and apie ce o f platinum tw istedtogethe r, and co nn ected w ith the galvan ome ter

, w hich is at adistan ce o f mo re than tw e n ty fe e t ; but yo u

.

perce ive that thew armth o f the fingers is sufficie n t to pro duce adistinct current—apiece o f iro n and coppe r, o r zin c and iro n

,doe s the same ,and

w hen I employ pie ces of bismuth and an timo ny the w armth of

the hand cause s the spo t o f light to pass o ff the scale and traverseaspace o f 15 o r 20 fe e t alo ng the w all. I may he re remark thatthe range o f the scale is 25 fe e t, and the distan ce o f the galvanome te r from the scale 40 fe e t.The galvan ome ter is w oun d w ith about turn s o f N0. 22

w ire , in tw o paralle l circuits, and has a re sistan ce o f fo ur ohms.

The galvan ome te r isat adistance o f abo ut tw en ty fe e t from the

lecture table . The o rdinary lime light is used fo r illumination .

I have he re o n e o fNobilis’ thermo -pile s, con sisting o fsixte en verysmall bars o f an timony and bismuth, the w ho le o ccupying aspace

of half acubic in ch this is so sen sitive that the mere approach of

o n CLAMOND ’S THERMO-ELECTRIC BATTERY.

the hand causes acurren t to appear, and age n tle touch of the

finger cause savio le n t defle ctio n of the galvanomete r.

It is o f course in differen t w hether on e of the jun ctions be heatedor the other co o led . Thus, if I pour afew drops o f ether o n the

pile , the defle ctio n is equally pow erful in the oppo site directio n .

As I have before remarked, this form of pile , w ith a largernumber of pairs and w ith suitable po lished refle ctors and scre en s,

formsthe mo st sensitive heat-measurer kn ow n ifmade in acircularform the heat of the smallest in sect w ould be easily show n .

It was so o n fo un d that curren ts w ere produced n o t on ly by dis-isimilar me tals but by the same metal in differen t state s of crystallisation , or of hardn e ss, w hich alters the molecular condition o f themetalandaffects its thermo -e lectric propertie s. Thus, hammering, ortw isting, o r stretching the metal, producesaperman ent effect. Sir

William Thomson , w ho has diligently investigate d this bran ch o f

electrical scie n ce , as w e llas o thers, show ed, in 1856, that the mere

temporary stretching of aw ire by w e ights o r compressing it byforce produce sachange in the thermo -e le ctric quality o f the me tal,w hich disappears as so o n as the stress is removed . Magn etisatio n of

apiece of iron o r stee l pro duce s the same effect. The influen ce of

mo lecular arrangemen t is in some case s very pow erful. Thus inbismuth a crystal, co nn ected by its side to lead, give s, un dercertain co ndition s,ate n sio n o f45micro vo lts ifco n n ected by its endthe po w er rise s to 65 ; and if the same me tal be pressed ho t throughadie , so as to formakind. o f harden ed w ire , its force in creases to 97.

Metalsare n o t the on ly substan ce s w hich produce them e -e le ctriceffects. Mo st o ther con ducting substan ces do the same ; thus thesulphide s of lead (galena), iro n pyrite s, copper pyrites, and the

sulphide s o f o ther metals, the native oxide o f mangan e se(pyro lusite ), pho sphorus, carbon , and o ther substan ce s, pro ducepow erful effe cts, and have be e n successfully employed in makingthermo-pile s. Se len ium is in fact by far the mo st them e -n egativesubstan ce kn ow n , be ing more than thirty times as pow erful as

There is an o ther source o f thermo-e le ctric pow er, viz. thatproduced w hen tw o pieces of metal are heated to differen t tem

perature s and co n n ected by afused salt capable o f conductingv0L. v. Z

ass o n cu stome rs TBEBMOB LECTBIC BATTERY . [110111533

e lectricity ; it se ems to be indifferent w hat me talis used or w hat is

the nature of the salt. The curre n t is alw ays from the hotter

me tal through the salt to the co o ler metal.The re is also a thermo -e le ctric e ffect pro duce d w hen certain

crystals are heated— the be st kn ow n of the se is to urmalin e , w hich,w he n heate d, exhibits e le ctricity o f high ten sion at its en ds— thee lectricity be ing po sitive at o n e e nd and negative at the other;

e ven broke n fragmen ts o f the crystalhave the same property.

We have hitherto spoken chiefly o f the e ffe ct produced byacon tact o f dissimilar metals, but the re isan o ther w ay o f producingathermo curre n t. Whe n tw o pie ce s of the same me tal are placedin co n tact, o n e hot and the o ther co ld, acon siderable thermoe le ctric curre n t is pro duced. I havc here tw o pieces o f iro n-w ire.1 heat o n e in the spirit lamp and place it in co n tact w ith the other;acurren t passe s through the heated jun ctio n from the hot metal

to the co ld ; if I heat the o ther piece of metal the current isre ve rsed .

Platin um, copper, zin c, and othe r me tals produce the same

re sult. Ho tand co ld me rcury produce n o such effe ct.Sir William Thomso n disco ve red the singular fact

, that w hename tal circuit is heated at o n e spo t, and acurren t is passed throughit,the heat is co n veyed by the curre n t in adirectio n depe ndent on

the nature o f the me tal. With iro n o r platin um the heat is carriedby the po sitive curre n t from ho t to co ld

, w ith copper and other

me tals in the reve rse directio n .

Pe ltier, in 1834,had disco vered asomew hat analogous effect

His the ory w as, that, w he n athermo curre n t w as fo rmed in acircuito f bismuth and an timo ny , there w as an abso rption o f heat at the

surface s o f co n tact at the w arme r jun ctio n ,and an evo lutio n ofheatat the co lde r jun ctio n , and that the same re sult w as obtained ifacurren t from any exterio r source w e re passed thro ugh sucha

circuit ; this fact is easily verified by experime n t. I have in thissmall box an arrangemen t by w hich I can se nd acurre n t fromasingle Sme e ’

s ce ll thro ugh acircu it o f bismuth andan timony ; inimmediate juxtapo sitio n w ith this is an o the r similar circuit,andthe w ire s from this last circuitare co n n ecte d to the galvo n ometer;there is n o e le ctric co nn ectio n be tw e en them, as the tw o are sepa

340 on CLAMOND’S THERMO-ELECTRIC BATTERY . [11th May,

T he table is extracted from Dr. Matthie sen ’s paper in the

Philo sophical Tran saction s for 1858 . Re ferring to the left-hand

co lumn o f figures it w ill be seen that he takes silve r as his zerometal , and, calling the effect ofasilver-copper pair 1, he measuresthe e lectro -mo tive force of allthe o ther couples by th is standard,tho se abo ve silver be ing con sidered thermo-po sitive me tals, andtho se be lo w it thermo -n egative .

The right-hand co lumn is atable calculate d from this by Profe ssor Jenkin

,sho w ing approximate ly the thermo -e lectric force of

each co uple in microvo lts fo r each degre e cen tigrade . Professor

Je nkin , ho w e ver, take s lead as his zero in stead o f silver. The

te n sio n s in the upper half o f the table are the refo re po sitive andtho se in the lo w e r half are n egative , and to o btain the po w er ofany po sitive and n egative couple w e must add the tw o together ;thus bismuth and an timo ny have afo rce o f 45 23 as compared

w ith that o f silver and copper, or ate nsio n of 68 microvo lts foreach degre e Ce n tigrade .

'As the se ten sio n s are re lative ly fixed quan tities, itmatte rs not inw hat o rder the me tals are combin ed ; a compo un d chain of

various pairs o f e leme n ts give s the same force as the tw o exteriore leme n ts. We may gain our te n sio n by un iting successivelybismuth, lead, copper, zin c, iro n , and an timony, the in termediateme tals be ing arranged in any o rde r w hateve r, or by taking thebismuth and an timo ny alo n e , and in bo th cases the re sultantte n sio n w ill be the same .

It is rather remarkable in regarding the o rder o f arrangemento f the me tals in this table that it do e s n o t appear to have anyre latio n w hatever to the order in w hich they stand to each o therasregards the ir po w er of co nducting e lectricity o r heat o r the ir re lativespecific heats

,o r the o rde r in w hich they stan d to each o theras

re spe cts the ir vo ltaic fo rce s. The old familiar coppe r and zinccombinatio n has very little thermo -e le ctric po w er, and the same is

true o f z in c w ith silver,platinum

,and carbo n . On the o ther hand,

bismuth and an timo ny, w hich have little vo ltaic pow er, standat

the extreme s o f the scale . Se len ium is singularly n egative , andgale naand some o f the sulphide s ve ry po sitive .

If w e se ek through the table fo r useful thermo-e lectric combina


tio ns, w e must remember that our e lemen ts ought to be very go o d

co n ductors of e le ctricity and very bad conductors of heat : theyshould also be cheap.

In the po sitive list bismuth, w hich stands at the head,is at pre

se n t avery expen sive me tal, and is also easily fused. Ge rmansilver and coppe r appear the best me talsavailable . In the n egativeserie s w e find iro n and an timo ny, and yet it is singular to find M .

Clam o n d employing iro n as his thermo -po sitive me tal; there is,ho w e ve r, areaso n for this w hich w ill appear he reafter. It is

remarkable that the alloy o fan timo ny and zin c w hich M. Clamo n duse d is so much more po w erfulthan e ither o f the e leme n ts alo n e ,be in g tw o and a-half time s mo re efficie n t than an timony. Thiscombinatio n w as, I be lieve , first made by Ro llman ,and is de scribedin Pogge ndorff

’s Annalen

,83

,84, and 89. Marcus (o r Markus)

employed asome w hat similar combinatio n . The thermo -e lectricfo rce is said to be the greate st w hen the tw o metals are combin edin the pre po rtio n of the ir chemical equivalen ts

, but the increasedresistance of the alloy n eutralise s the e le ctrical advan tage thuso btainable .

The thermo-e lectric re latio n s give n in the above table arero ughly true for ordinary temperature s. For every increase o r

de crease o f temperature some change o f po w er o ccurs,and at last

the ve ry order o f arrangemen t o f the e leme n ts is changed. For

example , at 300°

Cen tigrade iro n stan ds above copper, silver, andz in c. Sir William Thomso n

,w ho inve stigated the subject fully as

long ago as 1856, give s several such tables fo r differen t temperature s, and his admirable paper o n the subject w ill be fo un d in thePhilo so phical Tran saction s for that year.

The fact of thermo-e lectric inversio n w as first observed as earlyas 1823 by Professor Cumming, and it o ccurs to amore markedexten t w ith iron than w ith o ther me tals o n accoun t of the great(b ulge in thermo-e lectric force w hich that metal undergo e s atdifferen t temperature s.I have here apiece of zin c w ith apiece of iro n w ire tw iste daround it ; on applying heat to the jun ction acurren t passe s fromthe zin c to the iron , andas the temperature rise s the curren t increases in force ; presently, how ever, it attains amaximum, and

342 ON CLAMOND’S THERMO-ELECTRIC BATTERY. [11th May,

as the heat further increase s the force dimin ishes. As w e approachthe me lting po in t o f the zin c w e come to atempe rature at w hichthere is n o the rmo -e lectric action w hatever ; the n e edle stan dsagain at zero , as it did befo re the heat w as applied.But n o w ,

as the heat further rise s, the direction o f the curre n t isreversed,and the iro n be comes po sitive to the zin c, an d, if I w e re

to co n tin ue applying heat above the me lting-po in t of the zin c, thedeflectio n w ould be as great o n the o n e side of ze ro as it w as o n

the o ther ; iro n and copper pre sen t the same phen ome n o n .

No w ,in orde r to understan d the full mean ing of this phen o

men on , it is n ece ssary to refe r to the diagram No . 10.

o spae ss ccn rueaao s

MlCROVOLYS

Fig. 10.

This diagram is extracted from Pro fe sso r Je nkin ’s w o rk on

Ele ctricity and Magn e tism , but w as first given by Sir WilliamThomso n in his Bakerian Le cture o f 18563“ The figure salo ng thetop o f the diagram repre sen t temperatures ranging from zero

,o r

the fre e zing po in t, o n the le ft, up to 600°

Cen tigrade o n the right.The figure s o n the side o f the table repre se n t ten sio n expre ssed inm icro vo lts, and in the uppe r half o f the table the te n sio n s are pluso r po sitive , and in the lo w er half n egative . The zero o r m iddle o f

the table is o ccupied by alin e repre se nting lead,and it is assumed

fo r the purpo ses o f this diagram that this me tal has the same

the rmo -e lectrical pow er at allten sio n s from 0°

to 600°

Ce n tigrade'

.

No w this be ing so,the te n sio n s o f the o the r me tals at alltem

perature s are repre sen ted by the diago nal lin e s w hich cro ss the

diagram . Thus platin um at 0° Cen tigrade stands o n the le ft alittleThe diagram referred to w ill be found at page 178 of Prof. Fleeming Jenkin

’

s

w ork . He has reduced the tensions to abso lute measuremen t.

344 ON CLAMOND’S THERMO-ELECTRIC BATTERY . [11th May,

jun ctio n of each be ing immersed, the on e in melting ice and theo ther in bo iling w ate r.

The apparatus by w hich I make the se measuremen ts is w e llkn o w n to you , and is fully de scribed in the Society’

s Jo urnal,vol. ii . p . 21 , un der the name o faPo ten tiometer, so called be cause

W I N G BAYYERY

it is o n e o fmany forms of in strument for measuring differen ce s oE'

poten tials (fig. A w ire o f German silve r, w ho se re sistan ce 1:can vary at w ill from 1456 un its to 1456 un its

,o r 14560 un its,

has adifferen ce o f po te n tial o f 1. 4 56 vo lts main tain ed be tw e en its

extremitie s, by co n n e cting them to aClark’s standard ce ll

,and

main tain ing that exact po te n tial by the age n cy o f alarge thermobattery ; each un it therefo re repre se n ts 1

o favo lt w he n the re sistan ce is 1456 un its

, 7 0

1

0 ,w he n it is 1456 un its

,and W m o f a

vo lt w hen it is made 14560 un its ; the actual re sistan ce of the w irew hen the re sistan ce is at the lo w e st is 2 ohms

,and w hen at

the highe st 9772 ohms.

On the‘

low er scale the stre tched w ire enable s me to measure anyte n sio n up to 1 vo lt, and the 9 co ils o n the left, w hich are each of

the same re sistance , e nable me to add succe ssive ly 9 vo lts, so that I

can measure at o n ce any te n sio n from 1 & vo lt to 10 vo lts. On

the higher scale I can measure from T ,,—53 3 vo lt to 1

16 vo lt.

The te n sion s I obtain are as fo llow s1. Copper and iron2. Platinum and iron3. German silverand iron

LECTRIC BATTERY. 3 45

0 051 vo lts'0102

much higher the alloy o f

mfimw y an d zinc stan ds than that o fany o f the o the r e lemen ts.

(Mr. Clark here pro ceeded to make several measures o f the

po ten tialo f Clamon d’s piles by means o f the po te n tiome te r

, the

results o f w hich w ere sho w n to be in acco rdan ce w ith tho se givenin the table at pages 330I be lie ve that there are abo ut 250 o f these piles n o w in use in

England and abo ut 300 in‘

France , be sides o the rs in almomeverycivilise d coun try. I have see n alist o f n early 20 large firms o r

num

extremely co nvenien t for labo rato ry use , and by utilising the waste

heat of the kitche n fire s they might, I have n o do ubt, be advan

tage ously used fo r dome stic purpo ses.Mr. W. H. Pam : I am quite sure I shall be echo ing

'

the

tho ughts o f allhere presen t w hen I say that w e are most thankful

ne ver had anything pro duced be fo re the So cie ty in such aw aybefo re , and w e can o n ly hope that it w ill be the pre lude to se ve ralsuch papers. It sho w s this, that if go o d men w ill bring fo rw ardgo od subjects they w ill alw ays se cure go o d audie nce s ; and I amsure the audie nce o n this

,as w e ll as o n the last o ccasio n

,must be

take n asacomplimen t to Mr. Latime r Clark. The Po st Office authoritie s have had some experien ce o f the practical w o rking o f these

w o rking first 20,w hich w ere gra

really these five piles o f them e

I should men tion that the circuits

346 ON CLAMOND’S THERMO-ELECTRIC BATTERY. [11th May,

w e re allun der 100 mile s in le ngth. The re sultwas satisfactory, on ly,I am compe lled to say, certain faults deve lope d themse lves. In

w o rking outan ew thing w e must expe ct to mee t w ith faults ; faultsare simply the le sso n s o f experie nce , and if w e did n o t me e t w ithfaults w e should n o t succee d in advancing and reaching pe rfection .

The re sult o f the se faults has be en to produce that last impro vemen tw hich Mr. Latimer Clark explain ed, w here the dimin ished actio n of

the little je ts o f gas w as preven te d from be ing projecte d upo n the

me tal itse lf by the in terpositio n ofan iro n plate . This n ew fo rm hasn o t ye t be en introduced at Te legraph Stre e t, and w e ho pe w hen w e

in troduce it to be able to w o rk even agreater number of circuitsthan w e do at pre se n t. On e great merit the system has displayed isthis— that from asurface n o t much larger than this table w e havebe en able to w o rk these 90 circuits and to replace by the ir meansn o few er than 2535 ce lls. Any apparatus that in the se days ofhigh pre ssul’e econ omises space is in itself agreatadvan tage . At

the same time w e cann ot expect an ove lty o f this kin d to be in troduced w ithout some demerits e ither in the shape of expe nse or

o ther po in ts. At presen t our experie n ce has n o t enable d us to

arrive at any defin ite re sultas to expen se . The result is,up to the

pre sen t, the figures given by Mr . Latime r Clark,are ve ry n early

exact, viz. that the se five pile s co n sume 44 fe e t of gas pe r hour ;and from that it is n o t difficult to calculate w hat the co st w ill be .

I w ill n o t say mo re except this : that n obo dy can w atch the resultsof such experimen ts as have be en brought be fo re us , o r the w orkingof such an in strumen t as this, w itho ut fe e ling that the mo lecularthe o ry o f e lectricity— that w hich accounts for the display o f electri

cal effects by the co nversio n of o n e e n ergy to an o the r— mustrece ive mo re acceptan ce , for w e in the se experimen ts have thesimple change o f the mo lecular co n stitutio n o f bodie s pro ducingthe se co nditio n s w hich de termin e differen t e le ctrical effe cts.

The PRESIDENT : The time fo r clo sing o ur me eting is n earlyarrived ; but during the fe w min ute s that remain at our dispo sal w esho uld be glad to hear Mr. Higgin s, w ho , I be lieve , is n o t unac

quain ted w ith the se in strumen ts, shou ld he be dispo se d to favourus w ith any remarks. I may add that the paper is so in teresting,that the experiments have o ccupied so long atime n o t one

348 ON CLAMOND ’S THERMO-ELECTRIC BATTERY . [11th May,

tate copper, and asystem o f ve sse lsarranged to utilize the current

up .to the exte n t o f its capabilities w ould be diffic ult to manage .

The applicatio n s of this pile are very numerous. The force ofa

small pile w orking amo to r day and n ight could ke ep the w e ightsOfalarge clo ck always w o und up. Permanen t magn e ts for the

removalo f iro n from brass filings can be made and ro tate d by thesame battery. The en crustatio n o f steam-gen erating bo ile rs maybe to some exten t preven ted by the curren t from asmall pile builtaround the fin e o r any o ther hOt place . A small circle of te n pairsplace d above the flame Of asignal lamp w ould indicate the stateofaffairs to adistan t signalbox.

The tw o large st piles w e have had at w ork hadan e le ctromotiveforce e qual to about 120 vo lts. The e lectric are from these tw opile s w as about i-in ch lo ng, and could be main tain ed for anylength of time . On e small coke pile e qual to 20 vo lts

,and Offering

four ohms internal re sistan ce , w as kept at w ork for some mon ths,and performed mo st satisfactorily. It is very easilymain tain ed at itsfull po w er if the grate be stirred. about on ce every tw o o r threeho urs. A coke pile this size , built up w ith small

' bars, w ould con tain1200,and be equal in e lectromo tive force to 60 te legraphicDan ie ll

’s,

but tw e lve times that numbe r w o uld have to be jo in ed up quantitively to make the in ternal re sistan ce equal. Such apile

, therefo re , co uld do the w o rk o f at least 720 te legraphic Dan ie ll

’

s. Mr.

Pre ece sho w s that these pile s can be put to more w o rk than w ouldbe e stimated from the ir po w eras compared w ith o rdinary batte ries,I may the n safe ly say that such apile w ould do the w o rk Of 1000

ce lls at aco st of about 4d. per day of tw en ty-four hours.

Co sT or DEPOSITING ONE OUNOE OF COPPER BY VARIOUS PrLEs.

taken as.

Dan ie ll’sB ichromateGrove ’

s

Sme e’s

Thermo , heatedDo . heated

ON CLAMOND ’S THERMO-ELECTRIC BATTERY.

Price s taken asB ichromateN itricSulp. o f CopperSulp. AcidZin c

On the mo tio n o f the Presiden t acordial vote o f thanks w as

passed to Mr. Latimer Clark for his paper, and fo r the in tere stingillustratio n s by w hich it had be en accompan ied.

Mr. LATIMER CLARK : I have o nly to thank you fo r the kindman n er in w hich you have rece ived my paper, and I am gladif it has be en o f any use to the So cie ty . I may add that theapparatus I have used is at the se rvice o f any membe r w ho mayde sire to employ it fo r his o w n purpo se s for asho rt time .

am aw are that it is rather aco stly arrangemen t fo r asingle paper,but in do ing so my Object has be en that it might to some exten t be

at the service o f the membe rs.

The fo llo w ing Can didate s w ere then balloted fo r, an d de claredduly e lected :

As MEMBER

R . Saw er.

As ASSOCIATES

F. Thorn to n .

W . Dow n ing.

H . Kingsfo rd.

After w hich the Mee ting adjourn ed .

[22ndNov.

The Fiftie th Ordinary Ge n eral Me e ting w as he ld o n Wedn esday,the 22nd November, 1876, Mr. C. V . WALKER

,

Presiden t, in the Chair.

The Pre siden t ro se and saidGENTLEMEN

,— I am very pleased again to mee t you after our

long re ce ss, to meet yo u again as here to fore under: this veryho spitable ro of. Ho w ever much you and I may have be e n re st ing,and the n again w orking after our re spective ho lidays w ere e nded,the o fficers o f the So ciety have un que stio nably be e n mo st diligent— they must have had mo re w o rk than re st ; fo r they have broughtus in to the happy po sitio n that allarrears o f printing up to the

presen t date -are w o rked up, and No . 13 o f the Journal o f theSo ciety is very n early ready fo r issue . I say the prin ting has beenw orked up to the pre sen t date . It is so

,except that it w as thought

mo re co n ve n ie n t fo r Mr. Latimer Clark’s paper on the thermo

e le ctric batte ry, read at the me eting pre vious to the rece ss,and

the discussio n o f it w hich w as adjourn ed till this pre se n t me eting,might appear together in the forthcoming n umbe r. An d I mayalso state that arrears o f an o ther kin d have be en w orked up suc

ce ssfully, I mean the arrears o f subscriptio n s ; fo r I n e e d hardlysay that w o rking up the arrears o f prin ting w ould have be e n invain if the Treasurer w as n o t in po sse ssio n o f fun ds to pay thecharge s w hich the prin ter has again st us. I w ill n ow call upon theSe cretary to read the min ute s o f the last Ordinary Me e tin g.

The m inute s having be en read and con firmed and the list ofn ew candidate s read ,The PRESIDENT said I w ish to in fo rm you that the So cie ty has

re ce ived avery un ique,valuable

,and in tere sting docume n t since

last w e me t. It is in the Latin language , and w ill appear verbatim

in the Jo urnalo f the So cie ty, together w ith atran slatio n .

"l It isan

impressio n— n o t acopy o r reprin t— o f the o riginal commun icationmade by Pro fe sso r (Ersted re lative to the disco very o f e le ctro

The verbatim copy o f th is do cumen t, together w ith atranslatio n in English,w ill be foundat page 459 of the present number.

352 ON CLAMOND’S THERMO-ELEG’I‘

RIC BATTERY. [22ndNov.

pre ssure and are n o t so liable to be injured by the heat of the

battery.

The third improvemen t is in the method of heating. In stead Ofthe gas flame s impinging dire ctly upo n the bars o r against the ironcylinder w ithin the thermo -battery they n o w employ an innercylinde r o f earthen w are , w hich forms the cen tre of the battery,andthey build up the bars o f metal around the cylinder an d in closeco n tact w ith it, each bar be ing bedded up against it w ith asbestoscemen t. The flame therefo re can n o t get in co n tact w ith them,

and

they are le ss liable to be injured by heat, w hich w as the ch ief causeo f difficulty in the o lde r form o f pile .

An o ther advan tage is that the heat ismore un ifo rmly distributed,and w he n the gas is extinguished the battery co o ls much slow er.

T he rapid co o ling of the batteryafter the fire is extinguished Oftencause s fracture s w hen the gas is first lighted and the w ho le pile isco ld ; the re is more overagreat condensation o fmo isture

, w hich hadbe en suppo sed to cause the bars to crack and to injure them by

causing oxidation ; allthe se defectsare more or le ss obviate d by n ewco n structio n .

The n ext improvemen t is in the gas chamber. Tho se w ho use

these batterie s kn o w that the re is some time s an explo sion w hen

yo u first light them. They n o w use asafe ty gas chimn ey o f w iregauze in side the burn er, through w hich the gas passes befo re itemerge s from the burn e r, and the co n sequen ce is you can n o t haveany explo sio n .

They have also made an impro vemen t in the regulatio n o f the

supplyo f air as w e ll as o f gas ; be n eath the battery they have anarrangemen t by w hich adisc can be low ered o r raised so as to

adjust the amo un t o f air and in sure the mo st perfe ct combustionpo ssible .

Lastly, they further regulate the supply Of air by little co vers of

fire -clay place d o n the top of the battery. They con sist of perforated radial discs. Improvemen ts have also be en effected in thecoke form o f battery, and the n ove lties introduced are the se : theyhave tw o do o rs in the coke pile , bymean s o f w hich the combustioncan be in spe cted and the verticalbars on the fron t Of the pile can beeasily removed and replaced, clinkers to o can be easily remo ved,

ON CLAMOND ’S THERMO-ELECTRIC BATTERY. 353

w he reas formerly it w as n ece ssary to empty the pile to get out theclin kers. Theyalso have the same impro vemen t as that in troducedin the gas pile , that the bars are suppo rted by clay discs, and anyse t Of bars may be removed or replaced. There is also in the cokepile an improved me thod o f fe eding the fire and regulating thecombustio n . I have n o do ubt that w ith allthe improveme nts thattime and experien ce w ill indicate w e shall so o n co n sider thermo

pile s indispen sable fo r te legraph purpo ses as w e ll as for e le ctrochemicaldepo sition .

Mr . W . H. PREECE I have very little to add to w hat I said o nthe previous o ccasion w hen this subje ct w as mo o ted here . I thenmen tio n ed that six of these pile s had be e n supplied to the Po stOffice departmen t by the Company

,and had be en used. They

w ere employed o n the un ive rsal battery plan . At first tw en tycircu its w ere attached to the six pile s

,w hich w ere gradually in

creased by fives, un til at last fo rty-thre e distinct circuits w ere

w o rking simultan e ously from tho se six pile s. Each o f the se pile ssucce ssive ly failed, and every o n e from the same cause— that namedby Mr. Latime r Clark in his paper, viz .

,the overheating, by w hich

the co n n e ctio n be tw e en the tw o plate s w as fused o r destroyed.

The system of in troducing an in termediate plate , so as to w o rk byradial heat in stead o f the directapplicatio n o f heat, had be e n appliedto some o f them , but ow ing to the co llapse of the Company thecomple te se t promised to the departme n t has n ever be e n supplied ,and the re sult is that sin ce March last the experimen t has be en discon tin ued. I fe e l, how ever, bound to say the re sults give n w ere

so satisfactory as to make the use o f this battery very promising,and w e are in hopes that this Company w ill re cover itsp o sitio n , soas to be e nabled to supply tho se batterie s that are required to carryout the e xperimen ts. The results w e have fo un d in practice co r

respo n ded exactly w ith tho se stated in the pro spe ctus itse lf, andalso w ith the measuremen ts o f Mr. Latimer Clark. The con sump

tion o f gas w as 8 fe et per hour, and the e lectrical fo rce an d in ternalresistan ce agre ed w ith the figure s give n . When this o rde r is com

pleted, w he n the batterie s are again attached to the circu its, andafte r they have had satisfacto ry trial , I shall have great pleasureonce more in bringing the matter before the Society.

VOL. v. 2 A

354 ON CLAMOND ’S TEREMO-ELECTRIC BATTERY . L22ndNov.

Mr. CECIL WRAY (respo nding to the Pre siden t’s invitation ) said

I do n o t kn ow that I can say much in additio n to the able descriptio n you have heard from Mr. Latimer Clark ; but there are on e or

tw o things I may po in t o ut w ith regard to the increase in the

strength o f the bars, se cured by the adoptio n ‘

o f this in ternalto ngue , w hich may be in tere stin g. I have here some bars thathave be e n built in apile , w hich w as w o rking some co nsiderabletime . They have n o t be en in any w ay injured by heat o r otherw ise during that w o rking ; and I may also Obse rve that the pilew as made o f bars o f tw o o r thre e differe n t kinds. To te st the

re lative advan tage o f this lo ng i nte rnalpiece , I w illbreak o n e or

tw o o f the se bars, and you w ill have the opportun ity of see ing[breaking abar] that this has o n e of the se lo ng po sitives in it.Y ou w ill n o tice that it do e s n o t run right through the bar. You

w ill also n o tice that the bar ge n erally breaks just at the po in tatw hich this lo ng to ngue e nds, and that the remain in g portio n is fullysupported by the discs. The object o f the lo ng to ngue is to pro tectthe o uter and expo sed e nds , so that, should the bar ge t cracked atany time , the curren t w ill n o t cease ; and, w hen broke n to that

exte n t,the bar still clings toge ther. In abar I have here yo u w ill

se e the co nn ectio n w hich take s place .

This mode l sho w s the arrangemen t o f the bars aro un d the tube,again st w hich the ir in n er e nds abut and are in con tact. They areallbuilt in w ith clay o r o ther suitable mate rial

,so that n e ither air

n o r the products o f combustio n can affe ct the jun ctio n s ; co n

sequen tly, afte r w o rking a co n side rable time,there is n o t the

slighte st dete rioratio n o f the iro n po sitive s, suchas take s place w hen

they are n o t so pro te cted . In the large r pile (o f the coke machin e)the bars are built in vertical, in stead o f ho rizo n tal

,sectio n s, so

that they can be easily removed in the eve n t o f the pile be ingrequired to be take n from o n e place to an o ther ; w hereas fo rme rly,the coke machin e be ing alarge o n e

,it w as n e ce ssary to take it to

piece s en tire ly to allo w o f its be ing removed.

Mr. LEONARD WRAY, Sen . : I w ould ask permissio n to add o ne

o r tw o w o rds upo n the great po in t w hich has be e n me n tio n ed byMr. Latimer Clark. It is as to the abso lute use le ssn e ss o f amachin e that is liable to . fuse . Un less you can do aw ay w ith that

356 ON CLAMOND’S THERMO-ELECTRIC BATTERY . [22nd Nov.

and the n earer you approach to them the n earer you w illapproachto aperfe ct machin e . In this case I ve n ture to say that myson s have made avery de cided approach tow ards the first Object,that is, in Obtain ing aun ifo rmity of internalheating. The bars

abutting upo n this tube have almo st the same heat at the bo ttom asthey have at the top, as the tube is o n e glo w ing mass ; be side sthis, w he n you turn Off the gas you have o n ly to sto p the bo ttomand the top, and yo u in sure a co o ling do w n gradually. I n e edn o t te ll y ou in amachin e of this character it is mo st impo rtant toavo id sudden heating and sudden co o ling, that great change fromthe heat w e get from aBunsen burn er to the rapid co o ling caused byan inrush o f co ld air is very liable to crack the bars, and w he nthat is the case there is immediate dete rioratio n and con sequentde structio n . But by this system , you Observe , the co o ling is verygradually effe cted . This tube takes aco n side rable time to coo ldow n , more e specially as it is clo sed at the top and bo ttom. Thissudde n heating and rapid co o ling w as n o do ubt o ne o f the causesthat bro ught abo ut tho se disasters in the machin e s to w hich Mr.

Pre ece has alluded. Whereve r the inn er e nds o f the bars areunpro tected they must in evitably pe rish.Allthe o ther po in ts I thin k have be e n made so plain

‘

that I w illn o t tro uble yo u w ith further refe ren ce to them. I have simplyspoken o n this o n e po in t as be ing really at the ro o t o f the w ho leevil , and if a remedy has be en he reby Obtain ed

,o r eve n afair

approach to aremedy,I submit that acertain and impo rtan t im

proveme n t has be e n e ffe cted.

Profe sso r FORSTER : May I ask o n e que stio n o f Mr. LatimerClark o r Mr. Wray w ith regard to the actio n o f the to ngue

, which

is de scribed as be ing cast in to the bars o f this apparatus I am n o t

sure w he the r I have quite understo od the arrangemen t o f that ; ifI have , I do n o t understand ho w it acts. Itappears to me the effect

w ould be to dimin ish the re sistance at the expen se o f e le ctromo tivefo rce

, and that the to ngue exte nding from o n e e nd to w ards the

o ther o n e sho uld have le ss diffe re n ce o f temperature be tw e e n the

in ternal end o f the to ngue and the e nd at w hich the o ther pie ce ofiro n is co n n e cted than if w e had the piece o f iron mere ly stuck onat the o ther e nd. Ifmeasureme n ts have be e n made sho w ing w hat

ON CLAMOND’

S THERMO-ELECTRIC BATTERY. 357

the actio n se t up is they w ould be valuable , because the mere in creaseof curre n t w o uld n o t be co n clusive under the circumstance s. It

might be the result o f ade crease o f re sistan ce or o f an in crease o f

ele ctromo tive fo rce ; and it se ems po ssible that an actual diminatio n o f e lectromo tive fo rce might be more than compe n sated bythe diminutio n o f resistance .

Mr. LEONARD WRAY, Jun . I may say that the bars increasein e lectromo tive fo rce w he n the elo ngated end

,Or to ngue

,is

emplo y ed, and also that the in te rnal re sistance is dimin ished .

That w as aresult un expe cted o n o ur part,and I cann o t at prese n t

explain it ; but it is n everthe le ss the fact, and I may state , that w ehave apile so built that the bars are allexactly equally heated inorde r that there sho uld be n o m istake . While bars made exactlythe same w ay, but w ithout the to ngue

,gave ‘6125 vo lts

,tho se

w ith the to ngue gave 6 300, sho w ing an in crease o f n early tw ohundre dths o favo lt. This increase is small

,but it is de cided

,and

sho w s that n o po w e r is lo st by the to ngue , but rather that aslightgain is obtain ed.

‘ The in te rnal re sistan ce w ith the to ngue w as

thre e -te n ths ofan ohm le ss.

Pro fe sso r FORSTER : What w as the w ho le re sistan ce ?Mr. WRAY : 2 ohms, as again st 2 3. If the to ngue go e s the

w ho le le ngth o f the bar the e lectric fo rce is dimin ished,but as w e

use it it is in creased. I can n o t explain the reaso n . I should havetho ught it w ould have sho rt-circuited as you se em to infe r. If the

elo n gatio n w e re at the o ther e nd the curre n t w ould be dim in ished .

Pro fe sso r FORSTER : Is the to ngue put in from the heated e nd o r

the co ld end ?Mr. WRAY : It is from the co ld end— the outer end.

I may remark that casting the bars under pressure increases theelectromo tive force . Here is the result o f tw o bars cast from the

same me tal : o n e bar w ithout pressure gave 0 843, and o n e w ith

six in che s head o f pre ssure gave ‘0885,show ing an increase o f

Having referen ce to th is observatio n the fo llo w ing n o te has sin ce be en suppliedby Mr. W ray :

“Probably from adefe ctive bar,o r o ther similar cause , the above

results w ere as I stated but by aserie s o f tests (made in aman n er so as to insure

the greatest exactitude) w e have since fo un d that there is alo ss o f about 7 per

cen t. in e lectromo tive force ,and again o f about 12 per cen t. in resistan ce”— L . W .

[BB-J

353 ON A NEW FORM OF LIGHTNING-PROTECTOR [22ndNov.

0 042 vo lt. W e arrived at the se results by mean s o f Clark’sPo te n tiometer.

THE PRESIDENT having called upo n Mr. Clark to reply upon the

discussio n,

Mr. LATIMER CLARK said he had n o thing to add to w hat he hadstate d. He w as glad that this in tere sting discussio n had beene licited, and he fe lt himse lf happy in having be en the m ean s of

bringing the impo rtan t subject of thermo -e lectric piles un de r thecon sideratio n o f the So ciety.

On the mo tio n o f the Pre siden t, avo te o f thanks fo r the exhaustive and e laborate mann er in w hich he had treated and illustratedthe subject of his pape r w as acco rded Mr. Clark by acclamatio n .

Mr. Jamie son w as then called upo n to read his pape r On a

New Fo rm of Lightn ing Pro te cto rs for Te legraph Wire s andApparatus.

”

ON A NEW FORM OF LIGHTNING-PROTECTOR FOR

TELEGRAPH LINES AND APPARATUS .

By Mr. ANDREW JAMIESON .

Mr. PRESIDENT AND GENTLEMEN ,With yo ur kin d permissio n I beg to bring befo re yo ur n o tice a

subject, the in trin sic value o f w hich to the Te legraph En gin eerw ill

,I hope

,excuse my bo ldn e ss in in truding o n the pre cin cts ofa

pape r so ably w ritte n and so w e ll conducted as w as that by Mr.

Pre e ce o n“Lightn ing and Lightn ing-Co nducto rs in the year

1872.

In that paper the autho r po in ted out that from the lst o f Januaryto the 3 1st o f July in that year 94 6 per ce n t. of the variousin strumen ts employed in the Po stal Te legraph system in Englandw e re de stroyed, e ither by the direct o r indirect effects o f lightn ing.

Whe the r this large perce n tage has be en de creased o f late years bym o re care

,so far as the mean s o f de fe nce are con ce rn ed

,I am n o t

in apo sitio n to say , tho ugh I hope this in formatio n w ill be e licitedduring the discussion upo n this paper. Certain

,how ever

,it is,

360 ON A NEW FORM OF LIGHTNING-PROTECTOR [22nd

There is n o o vergro und o r uncove red w ire w hatever in circuit; :

be tw e en the tw o statio n s o f B ilbao and San tander, w hich w ere

w orking toge the r at the time o f the o ccurre n ce , the lin e be ingcompo sed o f

lst. 8-5 m ile s o f cable buried undergro un d at an ave ragfidepth o f 18 in che s ;

2nd. 46 kn o ts of submarin e cable from Las Arenas to

Sardifie ro ;

3rd. 1gmile o f cable buried undergroun d at adepth 0t

1 metre from Sardiiiero to San tander Office .

“As is gen erally the case in the se preservers, there w as agreatquantity of w ire w oun d ro und the bobbin , o f w hich o n ly a small:le ngth

,abo ut 5an in ch, I should think, w as fused, and that in abo ut

the m iddle o f the o utside layer o f w ire . A black spo t o n the in n e‘ :

surface o f the cylinde r marked the place w here the discharge hage scaped to earth

,but the fin e w ire did n o t

,how eve r

,to uch thc:

cylinde r,as the lin e w as, immediate ly afte r the discharge , fo un d t

be in sulated, the broken e nd o f the w ire having probably be efused. Allcommun icatio n w as naturally in terrupted till the preserver w as take n o ut o f circu it.

An exactly sim ilar case o ccurred during a thun de rsto rm ar

San tande r last year upo n the the n San tan de r-Lizard cable, when .

"

there w ere in circuit the 15 mile o f un dergro und land-lin e me n

tio n ed, and 5 11 kn o ts Of submarin e cable to the Lizard Office .

I am ,dear Sir, yo urs faithfully,

CH. GERHARDI , Manager .

The induceme n t w hich led me to endeavour to improve if po ssiblupon the m ean s o f pro te ctio n affo rded by the apparatus usually‘employe d fo r this purpo se w as fo und in the fact that the in stru/m e n ts o n the lin e s o f the We ste rn an d Brazilian Te legraph Com/

pany, upo n w hich I w as e ngaged , w ere pe culiarly liable to damagesfrom lightn ing. The se lin e s w e re laid o ut as fo llo w sA cable , the po sse ssio n o f the abo ve Company

,stre tche s from

R io de Jan e iro to Mo n te vide o , and is in te rse cte d at thre e po ints,name ly, San to s, San taCatharina, and R io Grande -do -Sul. Its

to tal le ngth is kn o ts.

FOR TELEGRAPH APPARATUS. 361

Starting from Rio Jan e iro— o n e terminal o f the en tire lin e— the

town-o tfice is co n n ected w ith the cable -house by aland-lin e , seve nmiles in length , w hich run s half-w ay through the to w n , alo ng theside of abay, over amoun tain , and afte r skirting the sea-shore fo rsome distance en te rs the cable -house

,w he re it jo in s the cable

through lightn ing-pro te ctors.From this po in t the cable pro ce eds to San to s, abo ut 230 mile sdistant

,and then ce again to San taCatharina, some 290 mo re .

From the cable -house at the fo rmer statio n tw o laud-lin es,each

3 miles in length, place it in co n n e ctio n w ith the to w n -o ffice ,

where the in strumen ts are placed in circuit, so that the lan dlines fo rm a lo op w ith the Rio Jame iro— San te s and San to s

SantaCatharinasectio n s. Exactly the same thing occurs at the

remain ing in termediate statio n s o f San taCatharina and R io

Grande-dO-Sul, Where pairs o f land-lin es, o f 11; and 13k mile srespective ly, co n n ect the to w n s w ith the cable -huts. At the forme r

station the gro und is expo sed and very irregular,w ith lo ng span s o f

w ire at place s w he re the nature o f the lo cality compe ls t he iradoptio n

,While at the latter the feature s o f the coun try are o f an

entire ly oppo site character. The distan ce be tw e e n the tw o to w n s

isabout 400 miles. From Rio Gran de-do -Sulthe cable co n tin ue son fo r 350 mile s more to Mo n te vide o

,w he re it e nds

,and w here a

single land-lin e 1} mile long place s the cable-ho use in co nn ectio nw ith the to w n .

Several in stan ces came to my n o tice of m irror and reco rder co ilsbe ing fused

,e specially at San taCatharina, w he re they o ccurre d

as ofte n as tw o o r thre e time s amo n th,although the in strumen ts

on the se lin es w ere alw ays pro tecte d by the Sieme n s plate fo rms o flightn ing-pro te cto rs

,but I n ever co uld discove r that any Of the

cable s had-

suffe red damage,finding as they did an additio nal pro~

tectio n in Sieme n s’s po in ted fo rm .

Afte r ascertain ing the fallibility o f the o rdinary plate pro te cto rI turn ed my atten tio n to the ge n eral subje ct of lightn ing-pro te cto rs,w ith aview to devising, if po ssible , some fo rm giving mo re certain tyof pro te ctio n to the i nstrumen ts under my care . I carefully co n

sidered the me chan ical and e lectrical de tai ls o f aperfect lightn ingprote eto r, and compared all the instrumen ts w ith w hich I w as

362 ON A NEW FORM OF LIGHTNING-PROTECTOR [22nd Nov.

acquain ted w ith the standard w hich I thereby raised. In o rder toe nable the members o f this So ciety to judge how far I have aecom

plished my task I cann ot do be tter than rehearse tho se principle supo n w hich I laid the foundatio n Ofmy compariso n .

It w ill,I think

,be unn ecessary fo r me to enter to any great

exten t in to the mechan ical prope rties w hich apro te cto r sho uldpo sse ss, o r the me rits already po sse ssed by the fo rms n o w in

gen eral use . Fo r fo re ign se rvice,at least

,the instrume n t shou ld

be as light and compact as po ssible , n o t to o expen sive,and so

made that should any portio n become damaged it may be easilyreplaced .

The e lectrical qualificatio n s of a go od lightn ing-pro tecto ralthough fe w ,

are o f the greate st importan ce . They may, I think,be summed up as fo llo w s1. Efficie n cy o faction .

2. Its use sho uld in n o w ay in te rfere w ith the circuit arrangemen ts.

3. In do ing its duty it should n o t break do w n the circuit.In orde r to preve n t any infringemen t upo n the se con d qualifica

tio n it w ill be Obvio us that w e must make use of some prope rtypo sse ssed by high-te n sio n e lectricity

,distin ct from tho se Of e le c

tricity o f the oppo site nature . Allthe e ffe cts produced by ele c

tricity may be in cluded in the follo w ing list, assuming light to beatte ndan t o n and in separable from heat1 . Me chan ical2 . Thermal .3. Chemical.4 . Physio logical .The chemical propertie s Of e lectricity are o n ly me t w ith , inpractice , in co nn ectio n w ith the battery, and tho se o f the physiological class are n e ver employed . We may therefo re dismiss the sefrom o ur co n sideratio n .

Electricity can produce mechan ical and thermal effe cts, eithe r

directly o r indire ctly, through the medium Of induction . Me

chan icalactio n in each case is e ither e le ctro static or e le ctromagn e tic.

To the fo rmer class be lo ng all the attractio n s and repulsio n sbro ught about by frictional e le ctricity

,o riginal o r induced ; to

364 ON A NEW FORM OF LIGHTNING-PROTECTOR [22nd Nov .

charge betw e en the plate s ; but astatic charge , like that w hichaccumulates w he n the lin e is under the influen ce o f the thun dercloud, darts at o n ce acro ss the die lectric, in stead o f traversing theco ils o f the in strumen ts.

The specific inductive capacity o fair is fo un d to greatly in creasew he n its de n sity is lessen ed, and apartial vacuum may be saidto be ago od co nducto r o f statical e lectricity,— SO much so

,in de ed ,

that at sealightn ing has be e n kn o w n to dive rt its course from a

thick copper lightn ing conducto r in orde r to traverse ararefie dco lumn of air behin d the mast, caused by the rapid mo tio n .o f the

ship through the atmo sphere . The mo st efficie n t pro te cto rs ye tmade are con structed o n this prin ciple , Varley

’sVacuum Pro te cto r

be ing amo ng the n umber. They are , ho w ever, as arule , expe n

sive ; and the existe n ce o f the vacuum is n o t alw ays asce rtainable,

sin ce by in spectio n it is impo ssible to say w he the r avacuum ismain tain ed o r n o t. There can , ho w ever, be little do ubt that, so faras e fficiency is co n ce rn ed, they are the n eare st approach to pe rfe ctio n at w hich w e have ye t arrived.Thermal effects are produced through the influe n ce of inductio n

,

as already sho w n,o r by the passage o f acurre n t thro ugh aw ire .

The thin n er the w ire , and the greate r the strength o f the curre n t,

the so o n er w e shall Obtain agive n amo un t o f heat. This principle is advan tage o usly made use o f in the co n struction o f manylightn ing-pro te cto rs— the o rdinary w o rking curren t n o t be ing o f

sufficien t stre ngth to fuse the fin e w ire o f abobbin,w hile the

passage ofavery stro ng curre n t do es so immediate ly.

A ve ry impo rtan t po in t, ho w ever, still remain s, viz.,the princi

ple o f po in ts. It is w e ll kn o w n that apo in t w ill give off e le ctricityw ith far greater facility than aspherical co nducto r. The explanatio n w hich Pro fe sso r Fle eming Je nkin gives fo r this pe culiar phen emen ou is, that the capacity o faspherical co nducto r varies directlyas the square o f the radius

,w hereas the den sity

,i. e . quan tity pe r

un it area, varie s inversely as the square o f the radius,so that the

less the radius o f the sphe re the greate r w ill be the den sity. Co n

sequen tly o n apo in t,w hich w e may assume to be an infin ite ly

small sphere , the den sity w ill be in fin itely great. It w ill in fact repe lits o w n parts infin ite ly, and w e can thus understand thatapo in t


w ill give off e le ctricity atamuch low er po ten tialthan any o therfo rm.

w e combin e the po in t prin ciple w ith that o f the fin e w ire,

o r arre ste r, as it may w ith proprie ty be termed, w e may w hen

th ey are prope rly arranged expect to me e t w ith ve ry satisfacto ryre sults. The que stio n w ith w hich w e have n ow to deal is ho w best tocarry out the se results in o rder to o btain the ir best effe ct. W e may

p e rhaps he re take acurso ry vie w o f the ir use up to the pre sen t time .

The very first lightn ing-pro tecto rs in use in Englan d w e re fo rmedo f tw o po in ts, Oppo sed to and in su lated from each o ther

, to w hichth e in-and-o ut w ire s w ere re spe ctive ly con n e cted. Late r o n severallo ng po in ts in terlacing w ith each o ther

,and w hich might mo re

appropriate ly be te rmed spike s, w e re inclo sed in acase,and so

made that each po in t w as oppo sed to o n e of the tw o plate s, which

re spective ly fo rmed the lin e and earth co n n ectio n s. Late r o n the

o riginal prin ciple Of oppo sing po in t to po in t w as again adopted, and

M e ssrs. Sieme n s in troduced at that time an ingen ious device, which

has remain ed to the pre sen t day almo st unalte red. I allude to thegro o ving o f the plate s of the ir o rdinary pro tecto r at right angle s toeach o ther. A number o f gro ove s are made o n the un der andupper surface o f each plate in such aman n er that an umber of

comparative ly sharp ridges are fo rmed at right angle s to eacho ther. It w ill thus be se en that at eve ry po in t at w hich any o n e

o f the ridge s o f the upper plate in te rsects,so to speak

,tho se o f the

o ther, tw o po in ts are formed, and it is amodificatio n o f this principle w hich I propo se to use in the pre sen t in stan ce .

So far as I am aw are , the in tro ductio n o f the arrester is Of a

m o re mo dern date , and it w illtherefo re be unn e ce ssary to trace thegradualfulfilme n t o f the law o f natural se lectio n in its case . It is

w o rthy o f remark, how ever, that it is by n o mean s n e ce ssary tou se so great ale ngth o f w ire as is gen erally employed in in strum e nts Of this nature . Thre e o r fo ur in che s o f copper o r platinumw ire , 0 03 in ch in diame te r, is, I think, amply sufficie n t. In

support of this fact I may add that n o case has e ver come to my

n o tice Of re corde r co ils, compo sed o fabo ut 300 yards of w ire o f the

abo ve gauge , be ing fused mo re than an in ch from the terminal,

an d I n eve r saw the w ire ofagalvan ome ter fused fo r mo re than tw o

866 ON A NEW FORM OF LIGHTNING-PROTECTOR [22nd

in ches and a-half, afact w hich has sin ce be en co nfirmed byexpe rimen ts made by Mr. Munro . The lette r from Mr. Ge r

already quo ted, gives afurther corro boratio n o f the tru thremark. The great draw back, as already men tio n ed, to thethe arre ster is, that, as so o n as it has performed its o ffice , it bdo w n the circuit ; fo r this, ho w eve r, I have made spe cial psio n

,as w ill be se e n from the de scriptio n w hich I am n o w a

to give , toge ther w ith the accompanying diagrams. I must

leave i t to your decisio n w hether o r n o t I have succe ssfu llyfo rmed the task w hich I se t myse lf.The accompanying diagrams sho w an outside plan , e nd e leva

sectio nal plan , and cross-sectio n o f the in strumen t.The seve ral parts in each Of the se view s are corre spo n

marked by le tters and figure s.

The land-lin e o r undergro un d w ire is attached to the te

(L), and the cable co n den ser or in strume n t to (C ) be tw e e n 1tw o po in ts the ordinary batte ry curren t fo r effecting signals pw itho ut leakage , but the lightn ing, o r its in duced curre n t, is traparre sted

,o r co nducted to earth.

(L) is o n e terminal o f the in side corrugated, or to o thed, cyli

(l), w hich cylinde r is suppo rted ce n trically, in side an o uter cyli

by ebo n ite w ashe rs (11) and The se w ashers are fi

in to re cesses in the e n ds o f and so arranged that cylin deris separate dand in sulated from cylin de r (2) byasfin e an in te rveair space , o r vacuum , as can be me chan ically adjusted. Cyli

(2) is bored and tapped throughout its length by afin e po ide ep screw o f from 40 to any de sired number Of threads. It

thus be clearly se e n that if w e have (say) 30 lo ngitudinal corrtio n s o r fin e po in ted te e th dut o n cylin de r and 50 threadscylinde r w e shall have cro ssings, o r oppo sin g po inpre se n ted fo r facilitating the discharge o f e le ctricity o f high te n sifrom cylinder (1) to the latte r be ing co nn e cted to earth bybrass slab (E), upo n w hich it re sts

, and aflat co pper ban d leadifrom terminal(10) screw ed there o n . 3) is the o ther terminalcylinder to w hich is fixed afin e ste e l spring. Be tw e en

end o f this spring and terminal (4) is tightly stre tched afi

platin um or copper w ire 0 03 in ch in diameter. Terminal (4)

FOR TELEGRAPH APPARATUS . 367

co nn ecte d to te rminal (5 ) by aflat copper strap, runn ing un dern eath the ebon ite slab

,upo n w hich the w ho le in strume n t is sup

po rte d. Be tw e e n terminal(5)and (O) is run asilk-covered platinumw ire ‘008 in ch in diame ter (previously ste eped inparaffin e o r she llac),w ith severalturn s taken ro un d the o utside cylinder o r

,if pre

ferred, any o ther earth co n n ectio n .

In o rder that the fusing or breaking o f the fin e w ire stre tchedbe tw e en te rminal (4) and the spring attached to terminal (3) mayn o t sto p te legraphic commun icatio n ate rm inal (6) is so placed andpro vided w ith an adjustable platin um po in ted scre w as to makeco n tact w ith the spring upo n its be ing re leased. A sim ilar co nn ectio n is formed be tw e e n (6) (7) and te rminal (5) by an undern eath copper strap spring and aseco n d fin e w ire . Sho uld thisW ire be fused o r broke n the spring attached to te rm inal (7w illbe re leased and make co n n e ctio n w ith aplatinum-po in tedscre w in te rminal w hich is in go od me tallic co nn ectio n w ith thebrass-plate and therefo re w ith earth, thus effectually earthingthe e nd o f the lan d-lin e o r unde rgro un d w ire and preven tingapo ssibility Of mistake as to w here the lo ss Of co n tinu ity has take n place .

The o rdinary me ssage curren t passes from land-lin e o r undergro und w ire at (L) alo ng cylinder (1) to te rm inal (3) by springand fin e w ire to by unde rn eath co n n e ctio n to and platinumw ire w o und ro und cylinde r (2) o r earth co n n e ctio n to (O ), andthe n ce to cable

,con de n ser, o r in strumen t. Sho uld the fin e w ire

be tw e e n (4) and spring (3) be broken , it go e s from (3) to (6) byundern eath co n n e ctio n to spring and fin e w ire to and

then ce as be fo re to (C ), cable , co n den ser, o r in strume n t.If lightn ing o r ahigh te n sio n e le ctricalcurre n t pass alo ng theland-lin e or unde rgroun d w ire it w ill, so far, if n o t altogether

,be

trapped to earth thro ugh the fin e film o fair (o r vacuum if such hasbe e n provided fo r) be tw e e n the po in ts o f cylin ders (1) andSho uld any part o f this curre n t pass beyo nd te rminal (3) it isOffere d the chan ce o f fusing the fin e w ire stre tched be tw e en the

e nd of spring (3) and term inal(4) (o r spring at 7 and te rminalFurther, in o rde r to le sse n the disturbing and damaging efl

'

e cts

upo n the cable , co nden se r, o r in strume n t, by any po rtio n o f the

high-te n sio n curren t w hich might pass thro ugh the stre tched w ire s

368 ON A NEW FORM OF LIGHTNING-PROTECTOR [22nd No v.

before fusio n takes place , I have arranged the larger w ire , be tw e en(5) and (C ), covered w ith silk and an insulating substan ce , so asto bring in to actio n the principle o f conductive discharge be tw e enthis w ire an d the earthed cylinderThe w ho le in strumen t is fitte d to an ebo n ite base (9)and in se rted

in an eat case o r box, w ith glass top and key, having co nven ien tho le s fo r the leading-in w ire s. Cylinder 2 is made in halve s so asto facilitate its be ing easily examin ed in case o f astro ng chargefusing its in te rio r po in ts to that o f cylin derThere is n o thing n e w to be claimed in the seve ralfeature s of

this pro te cto r and arre steras vie w e d from an e lectrical po in t ofvie w

,but I think I am co rrect in saying that they have n e ve r before

be en allcombin ed in o n e in strume n t and in asimilar man n er.

I may he re state that the above plan o f attain ing Oppo site po in tsby having lo ngitudinal te e th in the o n e co nductor an d a scre w

thread in the o the r w as de sign ed by m e w hile out in Brazil fo r theWe stern and Brazilian Te legraph Company, in February 1875,although I have foun d sin ce w riting this paper that avery similarde sign had be en previously carried o ut by Siemens as w ell as byaFre n ch gen tleman named Lemasso n .

Since this fo rm o f pro te cto r an d arre ster has be e n applie d to theWe stern and Brazilian Te legraph Company’

s lin e s and apparatusthere has n o t be e n asingle case o f injury to the ir cable s or in strume n ts by lightn ing, so far as I can learn .

The PRESIDENT : We have an o ther,— ashort commun icatio n on

lightn ing pro te ctors,w hich the Se cre tary w ill n o w read. Walker’s

co nducto rs having be en named , I may call atte n tio n to spe cimenso n the table befo re yo u. Amo ng them there are tw o co n ductorsw hich have be e n called upo n to do duty . The po in ts, as yo u w illse e

, are fused, and the fin e w ire s burn t. The length o f fin e w ireis less than the author o f the pape r tho ught. There are o n ly threelaye rs o n aw o ode n bobbin . The po in ts are o n bo th side s o f the

co il o f fin e w ire,and are pre se n ted to abrass cylin der co n n e cted

w ith the earth,w ithin w hich cylinder is the bobbin o f fin e w ire .

The SECRETARY read a commun icatio n from Mr. Webber,of

the South Devo n and-Co rn w all Railw ay; explain ing tw o forms of

lightn ing pro te cto rs in use o n that Company’s system.

The Fifty-first Ordinary and Fifth An nual Gen eral Me eting w as

he ld o n Wedn e sday, the 13th De cembe r, 1876, Mr. C. V.

WALKER , Pre side n t, in the Chair.

The PRESIDENT said : I have the pleasure to ann o un ce thataverybeautiful marble bust o f the late Sir Fran cis Ro nald has be en prese n ted to this So cie ty by Dr. Sieme n s ; also that apo rtrait o f the

late Mr . J. L. Ricardo , w ho se name is so w e ll kn o w n from his in timate co n n e ctio n w ith the early progre ss of the e lectric telegraph,has be e n pre se nted by Mr. Frank Webb andalso apo rtrait o fthelate Alexande r Bain

,pre sen ted by Mr. Latimer Clark . The latte r

ge n tleman has also pre sen te d to the So cie ty aco lle ctio n o f curiousspecimen s o fthe te legraphapparatus o f early days ; and I have myselfhad the Oppo rtun ity o f pre se n ting asmall co n tributio n to the earlyhisto ry Of te legraphy, viz. : the o riginalgutta-pe rchajo in t-to ngs,co n trived by Mr. Thomas Fo rste r

,o f Streatham

,in 1848 . T hese

co n tribu tio n s w ill be exhibite d at the so ire’

e to be he ld o n Mo ndayn ext.

Scrutin e e rs w ere appo in te d fo r the ballo t fo r Pre side n t andCoun cil fo r the e n suing year ; an d the Pre side n t an n oun ce d thatthe ballo t w ould be ope n ed and remain so un til half-past e ighto

’

clo ck.

The Acting Se cre tary the n read the An nual Re po rt Of the

Co uncil , as fo llo w s

ANNUAL REPORT FOR 1876. 371

ANNUAL REPORT FOR 1876.

The time has again arrive d w he n it be come s the duty o f yo ur

Pre side n t and Co un cil to ren der an accoun t o f the ir stew ardshipand an n o unce to the Members the progre ss o f the So cie ty duringthe past year as w ell as its pre se n t co nditio n .

The Preside n t and Coun cil o f the In stitutio n of Civil Engin e ershave exte nded the same privilege and behaved in the same handsome man n e r to w ards the So cie ty during the past year as theyhave do n e in every previo us year sin ce its fo undatio n . Our be stthan ks are due to them

,fo r to the ir fo ste ring he lp the con tin ued

succe ss of the So cie ty is in agreat measure to be attributed .

The Co uncil have reso lved to in crease the n umber o f Lo calHo n o rary Se cre tarie s

,and steps are n o w be ing take n fo r the

appo in tmen t o f gen tleme n to act in that capacity in tho se coun trie sw here the So cie ty is n o t at pre sen t repre sen ted. That such aco urse must prove to be o f the highest advan tage is eviden ce d bythe

,

list o f n e w candidate s from Paris an n oun ced this even in g, allof w hom have put the ir name s fo rw ard o w ing mo re o r le ss to the

repre sen tatio n o f Mr. John Aylmer, w ho se appo in tme n t asHo n o rary Secre tary for France w as an n ounced at the last An n ualGen eral Me e ting .

During the past year Mr. E. C . Crackn ell, Superin tende n t o f

Te legraphs in Ne w So uth Wale s, has be e n appo inted Ho n . Se e .

fo r Australia, and Mr. G. G. Ward, Supe rin ten den t in New Yo rkof the Dire ct Un ite d State s Cable Company, has re ce ived the sameappo in tme n t fo r the Un ited States. The list of Ho n orary Se cretarie s at the pre sen t mome n t the re fo re is as follo w s

JOHN AYLMER , CivilEngin e er, lFRANCE.

4,Rue de Naples, Paris,

W . E. AYRTON,

P ro fe ssor of NaturalPhilo sophy,Impe rialCollege ,Toke i,Japan ,

2 13 2

JAPAN.

372 ANNUAL REPORT EOE 1876. use ; Doe

CHARLES BURTON,

Telegraph Engin e e r, Bucuo s ARGENTINE REPUBLIC.

Ayres,

E. C . CRAcxNELL ,

Superin te nde n t o f Telegraphs fo r

the Colony o f New South AUSTRALIA .

Wale s , Sydn ey,

Le Commandeur E . D’AMIco ,

Directo r-Gen eralof the Italian ITALY .

Te legraphs, R ome ,

FREDER IO DELARGE ,

Engin e er o f the Belgian Tele BELGIUM .

graphs, Brussels,

C . L . MADsEN,

Great No rthern Te legraph Com: DENMARK .

pany, Copenhagen ,

C . NIELSEN ,

Directo r-Gen eralof the Ne rw e NORWAY .

gian Telegraphs, Christian ia,

Do n RAMON VIAL,

Directo r-Gen e ralo f the Chilian CHILI .

Telegraphs, Santiago ,

G . G . WARD,

Ge n eral Supe rintenden t Of the UNITED STATES OF

Dire ctUn ited StatesTelegraph NORTH AMERICA

Company, New Y o rk,

The additio n s to the ranks o f the So cie tyn umbe r in all76 . The se comprise

18 Fo re ign Members,11 Members

,

45 Asso ciate s,2 Stude n ts.

874 ANNUAL REPORT FOR 1876. [13th Dec.

STATEMENT OF RECEIPTS

By the Treasurer, for the

RECEIPTS.

By Balance 31st De er. 1875Subscriptio n s 1872

1873

1874

1875

1876

18771878

Publishing FundSale o f Jo urnalsCompo sition of Life Subscriptio n sDonation to LibraryMisce llan eous

2 s

STATEMENT OF

On 3lst

RECEIPTS.

3. d.

By Do natio ns 200 0 0

Compo sitions 191 15 0

To tal £391 15 0

ESTIMATE OF ASSETS

On the 3lst

LIAB ILITIES .

By Subscriptio n s in advan ceOutstan ding Acco un ts— Salarie s

Short-hand reportingAttendan ce an d R efreshmen tR en t, Fuel, Taxes, an d Clean ingPrin ting an d Statio n ery

Balan ce Cr.

ANNUAL REPORT FOR 1876. 975

AND EXPENDITURE

year ending 3lst D ecember, 1876 .

EXPENDITURE.

To Salaries— Secre tary and Clerical Assistan ce 2

Clerical Assistan ce to Treasurer

Sho rthan d Repo rterAtten dan ce an d Refreshmen tsat MeetingsPrin ting an d Station eryFurn iture and Fittin gsRen t, Taxes, Fue l, an d Clean ingOverpaid Subscriptio n s refun dedSir F. Ro nald’

s Library— InsuranceLegal Expen ses

H o

w

“

C

OO

S:

14 11 11

Pe ttyExpenses, in cludingPo stage an d co st o f issue

Jo urnals

64 12 2

Balance Cr. 129 6 7

To tal 2 8

(Sign ed) C . E . WEBBER , MAJOR R .E. , Hon . Treas urer .

J. SIVEWR IGHT,Acting S ecretary.

We have compare d the above Accoun t w ith the V o uchers an d Cash B ooks, an dfin d it to be correct, leaving in the han ds o f the Treasurer o n e hun dred an d tw en tyn in e po un ds, six shillings, an d seven pen ce .

J. WAGSTAFF BLUNDELL ,

FRED . CHAS . DANVERS, tAudt tm

CAPITAL ACCOUNT

D ecember, 1876 .

EXPENDITURE.

To Furn iture and Fittings

AND LIABIL ITIES

D ecember, 1876 .

ASSETS .

To Unpaid Subscription sFurn iture

Jo urnals so ld o r In hand.

in hand o f publishersOb j ects presen ted to So ciety

Cash In han d

axan m a

376 ANNUAL REPORT FOR 1676. [13311 Dec.

be fulfilled, but the Co uncil w ould at the same time take thisoppo rtun ity o f again asking the Membe rs of the So ciety to co n

tribute to wards this e nd. Original commun ication s, mo re thananything e lse

,are w an ted , and w ith aproperly-co nducte d Journal

n o be tte r medium it is ho ped n o w exists for the publicatio n of

re searche s in Electricity o r inve n tion s in Te legraphy than throughthe Journal o f the So cie ty.

A circular has be en addre ssed during the past year to the

Members o n the subje ct o f Papers to be read,and it is gratifying to

be able to an n o un ce that commun ication s, in allcase s o f value , havebe en already forw arded o r vo luntarily promised, w hich w illentire lyo ccupy the eve n ings at o ur disposal befo re the clo se of the

Se ssio n .

The re is but o n e po int more o n w hich the Coun cil fe e l it theirduty to dw e ll , and that is the paymen t o f arrears o f subscriptions.

The list of the se , altho ugh con siderably reduced, is still agreatdeal larger than it ought to be , and some special steps w illhave tobe take n fo r recovering them , o r fo r the removal from the

So cie ty’s bo oks o f tho se w ho , n o tw ithstan ding eve ry appeal, still

declin e to subscribe w hat is o w ing by them . But fo r this theCoun cil w ould have had the utmo st pleasure in co ngratulating theSo cie ty upo n the pro spect immediate ly be fo re them of aSe ssio n of

co n siderable prom ise .

On the mo tio n Of Mr. Gerhardi, se co nded by Mr. Langdo n, the

R epo rt w as unan imously approved and adopted .

The PRESIDENT : Be fo re ope n ing the discussio n o n the paper readat the last me e ting the Acting Secre tary w ill read acommun ica

tio n w hich has reached us from Mr. Aylme r,o urHo n o rary Se cre tary

in Paris, On afo rm o f Lightn ing Co nducto r used o n the Statelin e s Of Fran ce .

”

The Acting Secre tary the n read the fo llo w ing commun icatio nPar is, 9th December, 1876.

DEAR SIR ,—AS I se e that the subject o f Lightn ing Guards is to

be again befo re the So cie ty at the ir n ext me e ting,I tho ught it

might in tere st the members to hear some thing about the prin cipal

376 ON A NEW FORM OF LIGHTNING PROTECTOR [13311 Dec.

po le . The iro n bo x has strongly glazed side s to permit the state ofthe in side be ing se e n .

The seco n d guard co n sists of three brass plate s ; the uppe rmosto r first o f them carrie s 300 fin e silve red po in ts

, w hich are he ld atadistan ce o f o n e m illime ter from the se co n d o r middle plate . Thislatte r o n e re sts upo n athird o r last plate , but is in sulated from it bythe in te rpo sitio n o f apie ce o f varn ished shee t gutta-perchaor

paraffin ed pape r . Tw o me talpillars scre w ed in to the bo ttom plateho ld the top o n e in its place and make e le ctric commun icationbe tw e e n the tw o . The lin e w ire s are attached to bin ding screw s

carried by the middle plate , and the earth w ire to ascre w o n the

third o r lo w er plate . This guard acts asadouble discharge r, fo r anatmo sphe ric charge en te ring the cen tr e plate is, if w eak

,draw n off

by the po in ts, o r, if strong, go e s dire ct to earth by traversing thegutta-perchao r pape r she e t separating the ce n tre from the underplate . After this latte r happen s it may be n e ce ssary to replace thein sulating she e t w ith afresh o n e .

Several thousands o f bo th the se lightn ing guards have beenbrought in to service by the Fren ch Te legraph Admin in stratio n atdifferen t time s during the last e ight years. They co n tinue to givee ve ry satisfactio n , and are still large ly o rdered.

The Fre n ch Railw ay Compan ie s also use them , e spe cially for thepro tectio n o f covered w ire s in the tun n els.

Mr. ANDREW JAMIESON then read some suppleme n tal remarks tohis paper, and gave afurthe r de scriptio n o f his lightn ing pro te ctor.The PRESIDENT Befo re calling upo n the Members fo r the ir

observatio n s o n this subject, I w ould reve rt to the last me e ting,w he n “Walke r’

s Lightn ing Pro te cto r w as men tio n ed. As it

w as o f very an cien t date I w as unable to re call its histo ry at themome n t. I have bro ught o n e o r tw o o f them here to n ight. This[exhibiting] is o n e o f the conducto rs comple te

,ready to place in

the circuit o f ate legraph w ire . Its partsare asmall w o odenbobbin , aboutan in ch in length, andastout brass cylinde r fo r earthco n n e ctio n outside the bobbin

,112} in ch lo ng andfive-e ighths in side

diameter. The to tal le ngth o f the little in strumen t is 3 in ches,in cluding ate rminalat each end. Nin e yards

,w e ighing 21 grains

,

ofNO. 40 copper w ire are w ound in thre e laye rs on the bobbin ,and


on e of the terminals prese n ts three fin e po in ts to the earth

of the o ther te rminal. The former te rminal is scre w ed in to thebo bbin in co nn ectio n w ith o ne e nd o f the fin e w ire ; it carries a

spur, w hich pre sen ts six fin e po in ts to the earth-cylinder. He re

[exhibiting] is o n e w hich has suffered in prote cting an instrumen tfrom lightn ing, an d can be examin ed. The poin ts o f the spurfused, as is also some o f the so lid brass o n the inn er side o f the

cylin der. Here [e xhibiting] is an o ther, w hich has pro te cte dinstrumen t, and the spur po in ts are e n tire ly fused aw ay. He re

[exhibiting] is also o n e w hich has do n e duty ; the in side o f the

cylin der is much fused. These in strumen ts w ere brought in to use

in the year 1848 . Refe rring back to my diary, I find these

1848 , July 15 . Tunbridge We lle — Co ils o f Tunbridge instrume n t and be ll fused . Ne w lightning co nductors n ot up .

1848,Se ptember 25 . Margate .

-Fitted my lightn ing co n

dueto rs.

1848 , October 6 . Lo ndo n — Fitted w ith movable and lightn ing

1848 , Octo be r 28. Sho rt sto rm . Tunbridge Wells . Lightn inge n tered ; darte d from bo bbin g w ire o f lightn in g co nducto r to

cylinde r ; burn t o ff silk ; co nn ected w ire w ith cylinder, and savedthe in strume n t.Of late years I have attribute d a great deal o f the immun ity

o f o ur te legraph line s from serious damage by lightn ing to the facto f the block system-be ing universally ado pte d, so that the w iresgen erally te rminate in earth so fre quen tly . There are lying on

the table tw o of the o ldest lightn in g pro te cto rs w ith w hich I amacquainte d. That w ith balls and po in ts w as used be fo re 1845 . The

North Ke nt lin e , erected by Mr. (n o w Sir W. F. ) Co oke in 1849 ,w as pro vided w ith ado uble -barre lled lightn ing co nducto r

,some

w hat the same in principle as min e . The instrume n t yo u w ill findfully de scribed in the Electric Telegraph Man ip ulato r, published in185 1. I shall n o w be glad to hear any remarks w hich ge n tleme nmay have to ofl’

e r on the subject.

880 ON A NEW FORM OF LIGHTNING PROTECTOR [13th Dec.

Mr. LATIMEB CLARK : I beg to bring unde r the n o tice o f the

So cie ty aprin ciple o f co n structio n o f Lightn ing Promctors w hich Iin ven te d alo n g time ago , and w hich I think w as w o rthy o f more

n o tice than it re ce ived at the time . It is w e ll kn ow n that w hentw o plate s are laid n ear toge ther, o w ing to the effect o f in ductionthe facility w ith w hich aspark passe s be tw e e n the tw o plate s is n o tso great as w he n apo in t is pre se n te d to aplate . But w ith lightn ing pro te cto rs having po in ts it depends upo n mechan ical skill hown ear you can ge t the se po in ts w itho ut danger o f co n tact Myobject w as to e nable

"

yo u to in sure clo se proximity o f the po intsw itho ut refe ren ce to the skill o f the mechan ic. I have amode lhere [exh ibiting]. This bo ttom plate is an earth-plate o f iro n .

Upo n this I place e ither athick film o f varn ish o r apiece o f thincarbo n pape r

,o n w hich I place the upper plate

,pie rced fullo f ho les

each o f w hich co n tain s alo o se pin o r po in t. The pe culiaritythat the se po in ts are allfre e to slide ve rtically w ithin the plate so

lo o se that they allfall do w n and re st o n the ir po in ts o n the paperco vering o f the plate , so that w hen put in to po sitio n each po in t isseparated from the earth-plate o n ly by the thickn e ss o f the varn isho r tissue o n w hich it re sts. The w ho le are the re fo re at au n iformdistance from the earth-plate s dependen t upo n the thickn e ss o f thefilm. I think upo n that prin ciple auseful fo rm o f lightn in g protecto r may be co n structed, although I have n o t myse lf attemptedto bring it in to practical use . I w ould me re ly add, in case s liketho se Mr. Jamie so n de scribed at the last me e ting, w he re the protecto r has to be placed at some distan ce from the office

,it w ould,

I think,be an advan tage to ado pt some arrangeme n t by w hich,

through the age n cy o f an e le ctro -magn e t, by se n ding a curren t

the uppe r plate may be lifted up from the lo w e r o n e ; the act o f

lifting up the po in ts and allo w ing them to fall again w ou ld breakany co n tact o r fusio n thatm ight have be e n caused by lightn ing

,and

might be use ful also w he n te sting the lin e in case s w he re the protecto r is in acable house at some distan ce from the o ffice . I mayadd

,that acheap fo rm o f this pro tecto r can be had by lOOping or

suspe nding lo o se w ire to the uppe r o r lin e -plate , and allo w ing itto re st at an angle o n the bo ttom plate s, w ith tissue in te rpo sed ; theme re shaking o f the pro te cto r w o u ld at o nce break any co n n e ctionformed by lightn ing betw e en th e lin e and earth.

ssz ON A NEW FORM OF LIGHTNING PROTECTOR [13th Dec.

the globe . It is n o t that thunderstorms are more frequen t here,

fo r w e kn ow that in this temperate climate they are fe w and farbe tw e en . No r are they mo re in te n se ; because compare d w ith theroaring lio n s that w e hear o f in tropical regio n s our thun derstormsare more sucking do ves. But it is because in this small coun try ofo urs w e have an e n o rmo us n e tw o rk o f n early m ile s of

w ire an d abo ut in strumen ts co n cen trated over asmall area.He n ce n o little puny thunde rsto rm can approach our sho re s and

spe nd itse lf upo n our hills and valleys w ithout embracin g in itsinflue n ce many mile s of the se w ire s and many o f the se in struments.Thus it is that the n umbe r o f accide n ts from lightn ing in Englandare so n ume rous.

t on I brought this subje ct befo re the Socie ty o n apre viouso ccasio n , I sho w ed that from the lst of January, 1872, to the e ndo f Ju ly in the same year, the re w e re n o few er than 897 lightningaccide n ts. Taking the w ho le o f 1872 toge the r

,there is n o doubt

that in England w e experie n ce at least faults from lightn ingitse lf. NO do ubt the year 1872 w as ayear o f maximum in te n sity.

Pro bably thun de rstorms, like auro rae and earth-curren ts,o ccur

mo st at stated periods. The pe riod of the tw o last is kn o w n to betho ut e leve n years. Tho se periods have n o t ye t be e n de te rmin edfo r thunde rsto rms. 1872 w as, as I have said

,amaximum season ;

sin ce the n the in te n sity o f the sto rms has be en gradually dim in ishing . During the past year, from No v . lst

,1875 , to 30th No v.

1876 , the lightn ing faults w hich w ere expe rie n ce d in 1872

have falle n do w n to 442, so that in the last year, o n the w ho le po stalte legraph system o f England

,w e have suffe red 442 time s from the

effe cts Of lightn ing.

Ne w lightn ing deve lops itse lf in tw o fo rms. The re are the directdischarge and the induced curre n t due to the approach

,discharge ,

o r departure o f acharged clo ud. We do n o t suffe r much fromthe dire ct discharge . When the w ire s o r apparatus fo rm apathfo r the discharge f rom the clo ud to the earth

, everythin g o f course

is shattered . I have seve ral reco rds Of such case s ; some o f themare in te re sting, and I w ill me n tio n o n e w hich I have take n fromarepo rt from South Wale s. On May 25th, 1876, ase ve re thundersto rm o ccurred about 8 a. 1n . in the n e ighbo urho o d Of To n du

,last


discharge destroyed an ee dle instrume n t,

fused the gaspipe , lit the gas, and burn thorse , acow , and thirty turkeys, w e re

The induced effect o f charged clouds deve lops itse lf in the fo rmo f in tense curre n ts trave rsing o ur w ires and ope rating our instrume nts. They vary in directio n and strength. At time s they cann o tbe distinguished from w orkin g curre n ts. A postmaste r obse rved,o n August 24th , that apale blue flash moved hisA B C in strume n t

o n e le tte r, adarke r flash moved the in dicato r tw o le tte rs,in thre e

in stances three le tters, and an o ther four, and in on e in stan ce theindicato r w as moved as many as te n le tte rs. Thus

,be tw e e n the

direct discharge and the w o rking curre n t w e have vario us stage s inthe strength o f the curre n t pro duce d by atmo spheric e le ctricity

,

de n ts o n po les,w ire s,and apparatus.

rare ly suffered . Insulato rs w e re some time s crackedsmashe d. The re w as o n e authe n ticate d in stance o f

tw o in sulato rs falling co in cide n t w ith a flash,but n o trace o f

frequen tly de stroyed by the passage o f the discharge .

The re w as an instance o f this atAppledo re,No rth Devo n

,in w hich

a terminal po le w as thirty yards from the office . The dischargeline w ire , and passe d thro ugh the gutta-pe re haw ire toTw en ty yards o f this w ire w e re e n tire ly de stroyed, and

w ire in side the gutta-perchaw as en tire ly

aw ate r-pipe underun ctio n of the earth-w ire and w ater-pipe the leadw ate r escaped. The casing w as split to piece sbe tw ee n the leading-iaw ire and the w aterpipe .

No . 8 iro n carried the charge aw ay perfe ctly.

in w hich the leading-iasome place s dissipated,

384 ON A NEW FORM o r LIGHTNING-PROTECTOR [13th Dec.

Some time s w e have had acciden ts in unde rgroun d w ires. Tw o

o r thre e faults are sho w n o n this board, w he re the charge made acomple te ho le thro ugh the gutta-percha, the edge s be ing scarred,burn t

,and carbo n ised ; but it is in o ur apparatus w e prin cipally

suffe r,and Of tho se 442 faults I have me n tio n ed n early allhap

pe n ed in the apparatus. T he character o f the faults is as follo w s198 co ils w ere fused

,and 75 magn e ts w e re demagn e tised 20

A B C in strume n ts w ere deadjusted 149 K pro te cto rs w e re fusedo r o the rw ise injured .

With regard to the mode o f pro te ctio n , Mr.Walke r has bro ughtbe fo re us an in te re sting histo rical re co rd o f w hat w as do n e in thisw ay in 1848-49. But the Ele ctric Te legraph Company

,w ho first

e stablished the comme rcial system o f te legraphy o f this coun try,spe edily abando n ed the use o f pro tecto rs, fo r the simple reason

that they fo und by experien ce that the pro te cto rs themse lve s produced mo re faults than they w ere de sign ed to preve n t. In thosedays w ire s w e re fe w , and in strumen ts w e re scattered

,and sto rms

passed o ve r the coun try harmle ssly ; but w hen the system was

mo re exte nded and it fe ll in to the han ds o f the Po st Office it waseviden t that pro te cto rs be came e ssen tial. Previo us to that

,ho w

eve r, Mr. C . F. Varley had taken advan tage o f the expe rimen t of

Faraday, w hich sho w ed that e le ctricity of high te n sio n fle w acrossa sho rt air space in pre fe re n ce to taking aw ire circu it. He

simply kn o tted o r tw iste d the tw o silk-cove red e nds of the co il-w iretoge ther w ithout in te rfering w ith the w o rking curren ts, but e nablingcurre n ts o f great in te n sity to fly acro ss and to avo id the co il.This w as apro tecto r as far as the e vil w as co n ce rn e d

, and it

po sse ssed the prin ciple w hich Mr. Treue n feldadvo cated, and w ith

w hich I fully co n cur, that the pro te cto r should be capablei

o f be ingeasily re paired. The tw iste d w ire w as subseque n tly w o un d aro unda boxw o od bobbin , w hich in its turn w as replaced by a brassbobbin co n n ected to earth , and that in its turn by abrass tubearound w hich afin e w ire w as co iled, so that by apro ce ss o f evo latio n the pro tecto r used by the Po st Office became this little protecto r w hich Mr . Tre ue n feld has sho w n this eve n ing.

Po in ts have n o t be e n very much used in any fo rm , but platecon ducto rs are much used , and ce rtain ly sho w themse lve s to be

386 ON A NEW FORM OF LIGHTNING PROTECTOR [13th Dec.

charge , how ever in ten se o n reaching the land-lin e , is so reduced in

po te n tial before it e n te rs the cable that it be comes perfectly harmle ss. The fin e w ire is abroad o ften place d n ext to the cable

,but

this is afatal erro r, for the charge that fuses the w ire must n ecessarily also e n te r the cable . If, ho w ever, the vacuum pro tector, orany pro te ctor, be be tw e e n the fin e w ire and the cable

,it may be

fused w ithout dange r to the cable , for the pro tector w ill re duce thepo ten tial o f the charge befo re it enters the cable .

In some cases lightn ing pro te ctors are attached directly to thelin e -w ires, the binding w ire s be ing turn ed dow n and the ends

po in ted in the dire ctio n o f the pin of the insulato r. This hasproved to be ave ry effe ctive lightn ing pro te ctor. Pro bably themo st effe ctive pro te cto rs in Englan d are the earth-w ires, w hichexist at n early every po le .

.

No tw ithstan ding the fact that n earlye ve ry po le in Englan d has alightn ing pro tecto r— e very in strumenthas apro tecto r o f some sort o r o ther— n everthe less in the past yearw e have suffered n o less than 442 times from the effects o flight

n ing. I do n o t mean to assert that lightn ing has defeated us ; onthe co n trary

,I think w e have succe eded in defeating the lightn ing;

but in po int o f fact there are curren ts be tw e en w hat are actualw o rking curren ts and w hat are curren ts o f suffice n t in te n sity tomake pro tectors ope rate , of such strength and duratio n as to fuseco ils an d deadjust apparatus. He n ce w e can n o t hope to be e n tirelyfre e from lightn ing in terfere nce . We have really made o ur lightn ing pro te cto rs to o se n sitive . They are to o frequen tly subjected tocurren ts o f in ten sity n o t high e n ough to o vercome air space s, orspace s o f paraffin pape r, but stro ng en ough to damage co ils. How

eve r se n sitive Or ho w eve r coarse w e make the pro tecto rs w e shalln eve r tho roughly preve n t lightn ing from injuring our apparatus.I do n o t think

,ho w ever, w e have ye t Obtain ed the de sideratum of

athoroughly go od pro tecto r. What w e w an t is asafe pro te ctorsafe to pro te ct o ur apparatus and safe to preve n t putting o n faults;and un til w e do po sse ss such apro te cto r I do n o t thin k it can besaid that in this particular bran ch of our pro fe ssion w e have reachedpe rfectio n .

Mr. R . VON FISCHER TREUENFELD I am very much pleased tohear that the opin io n o f so high an autho rityas Mr. Pre ece , based

FOR TELEGRAPH APPARATUS . 387

o n the re sults o btain ed in the British Po st Office Te legraphs, agre e sw ith min e

,that is

,that the Siemen s’ lightn ing discharger is mo st

efficien t in its w o rking.

Mr. Pre e ce con siders it an open que stio n w hether aplate discharger w ith alayer o f paraffin ed paper betw e e n the plate s is proferable to o n e w ith an air space o n ly ; the fo rmer he co n siders tohave the disadvan tage of in troducing ahigh re sistan ce to the

atmo spheric e le ctricity ; the latte r is open to o bje ctio n o n accoun to f the e bo n ite w ashe rs w earing aw ay in the co urse o f time andthereby changing the in terve n ing air space .

I beg to draw Mr. Pre e ce’

s atten tio n to Sieme n s’ plate lightn ingdischargers of more modern co n structio n

,w hich are e n tire ly fre e

from the Obje ctio n o f the ebo n ite w ashers. From the o n e exhibitedo n the table you w ill se e that the lin e and earth-plate s are mainfain e d at the ir original distan ce from o n e an o ther, w ith ebo n itew ashe rs,and are n o t liable to any change o f the ir re lative po sitio n s.

Mr. PREEOE : My obse rvatio n s amoun ted to this : my Objectio nto air space s w as that you could n o t bring your tw o plate s so clo seto ge ther as yo u can w he n they are separate d o n ly by athin pieceo f paraffin pape r ; you can the n bring them to almo st an in fin i

te simaldistan ce from each o ther ; and that, w hen yo u use an air

space , you are liable to have the plate s forced toge the r by adischarge w hich w o uld pass by harmle ssly if paraffin ed paper he used .

Pe rso nally, ho w ever, I prefer an air space to the in te rpo sitio n o f

an y die le ctric o r co nducting medium o f high re sistan ce , fo r an airspace appears to me to fulfil exactly the co ndition s required fo r alightn ing pro te ctor

,that is, it o ffers an infin ite resistan ce to the

w o rking curren ts and ave ry lo w re sistan ce to curren ts o f high’

in te n sity.

Mr. SAUNDERS : As to the pro te ctio n from lightn ing o f cablesco n n e cte d w ith aerial lin e s I have alw ays foun d that the fin e w ire

guard ,is sufficie n t.

The cable s o f the Medite rran ean Exten sion Company from Sicilyto Malta, and Otran to to Co rfu , the fo rmer w ith about seve n ty,andthe latte r w ith about tw e lve mile s o f ae rial lin e in circuit, w ere

fo rme rly pro te cted by afin e w ire o f about thre e fe e t lo ng, inclo sedin aglass tube fo r safe ty. The se w ire s w ere freque n tly fused and

2 e 2

888 COUNCIL FOR 1877. [lath Dec.

the glass tube fused and broke n , but in n o case has there be e n anydamage to the cable s. Se e ing that the glass tube s broke , gave methe ideao f in clo sing aSpiral o f fin e w ire in abrass tube (co nn ectedto earth), w ith discharging po in ts at each e nd. By placing it horizon tally w he n the w ire w as fused, the ends fe ll o n to the in side of

the tube and thus put bo th ae riallin e and cable to earth.

At Otranto the Eastern Company’

s Cable to Zante is also con

n ected to ashort le ngth o f aerial lin e . The w ire s w ere so often

fused there that the superin te nde n t,Mr. Eggingto n , de sign ed a

fo rm of guard,exhibited o n the table , combin ing the w ire and

plate guards.I was in hopes of rece iving from Maltasome in formation as to

the actio n o fmy tube lightn ing guard in time fo r this m e e ting, but

it has n o t yet reached me .

The discussio n was then clo sed, avo te o f thanks, o n the moti

on

o f the Presiden t, be ing unan imously accorded Mr. Jamie so n forhis paper.

The Presiden t ann o un ced the result of the ballo t to be as

President.

PROFESSOR ABEL , F.R .s.

Vice-Presidents.

MAJOR J. U. BATEMAN—CHAMPAIN , R .E .

PROFESSOR G . C . FOSTER , F.R .S .

W . H. PREECE,

CARL SIEMENS,

Members of Council.PROFESSOR W. G. ADAMS

,F.R S.

CAPTAIN ANDERSON,R E.

CAPTAIN ARMSTRONG,R .E.

G . VON CHAUV IN .

H. G. ERIOHSEN .

COLONEL GLOVER,R E.

EDWARD GRAVES.

CHARLES HOCKIN , M.A.

,C E.

LOUIS SOHWENDLER , Member of Councilof Asiatic S ociety.

890 NEW MEMBERS . [13th Dec. 1876.

ASSOCIATES

J. O. L. Bern e r.

J. Probert.J. G. Tro tt .

W. T. TImbridge .

T. B . Webbe r.

The Me eting then adjourn ed .

ORIGINAL COMMUNICATIONS .

NOTES ON ELECTROLYTIC POLARISATION .

BY PBOFESSORS W . E. AYRTON AND JOHN PERRY,

Professors at the Imp erialCollege of Engin eering, Tokio , Japan .

From De cember 1875 to August 1876 w e made several experimen ts o n po larisation phen omena. An account of the pre liminaryWo rk w ill, w e hope , he found o f some in te rest.Tw o platinum plate s, each 10 by 8 cen timetre s, w ere placed pa

ralle l at 213 cen timetresapart in amixture o f pure w ater and sul

phuricacid (spe cific gravity l'Ol6at 50° These plate s could beconn ecte d by akey w ith the po le s o faDan ie ll’s ce ll, the re sistan ceof conn ection s, galvan ome ter shun ted, and of the ce ll

,be ing abo ut

8 ohms. The curren t flow ing thro ugh these conn e ction s w as

measured in farads. The platinum plate s w ere perman en tly co n

n ected w ith the e lectro de s o f aquadran t e le ctrome te r. Whe n thecurren t w as broke n the plate s w e re left insulated , and subseque n tlyco n n e cted by re sistan ce co ils and ave ry de licate galvan omete r.

W e arranged abreak-circuit-chro n ograph, using aMo rse ink

w rite r, w o rked by the laborato ry clo ck,to record the time w hen

taking readings of the rapid diminutio n o f curren tand of differen ceo f po te n tials.W e w ould here say afew w o rds about the measuremen t o f adeflection w hen it is de creasing very rapidly. Suppo sin g thatthere is aco n stan t defle cting couple acting on avibrating bodyw hich is sw inging, w ith decreasing sw ings, about its po sitio n o f

ultimate re st, w e kn ow that its mo tion may be calculated if w e

imagin e that it is e veyw he re re tarded by afo rce varying as theve lo city o f the body (se c T homso n and Tait’s Eleme n ts o f Natural


Philo sophy, article s 294-6,and Cle rk Maxw e ll’

s Ele ctricity, article s730 Thus in arefle cting galvan ome te r o r e le ctrome te r

,a: is

the distan ce at the time , t o f the moving spo t o f light from afixedpo in t 0 o f the scale , and ifais the reading o f the po sitio n o f rest

o f the spo t the n the equatio n o fmo tio n is

ft"

; K (a zi t”,

w here K is aco n stan t depen ding o n the momen t o f in e rtiao f then e edle , & c.

,and K’

is aco n stan t depending on the visco sity , &c. of

the surro unding medium. No w ,w hen w e suppo se that the current

o rd ifl'

e re n ce o f po te n tials is co n stan t during the sw inging,that is

that ais aco n stan t, it is easy to so lve this differen tial equatio n , aso lutio n be ing

w — a=

w he re c and c’ are co n stan ts. If al, $ 2, &c. are the readings

o f succe ssive e lo ngatio n s (w he n w e speak ofan e longatio n w e mean

the reading o f the limit of the sw ing), then w e may begin to counttime from (say) the first e lo ngatio n , and if T is the half time ofa

complete o scillation of the n e edle

I

And give n and w e find from the first thre e o f the aboveequatio n s that

2x1“3 w ea

No w ,suppo se w e kn ow athe po sition o f re st of an ee dle w hich w e

have se t sw inging, then taking the e lo ngatio n s m

g, and we,w e

se e that if the n e edle obeys in its sw inging the above law , then

(“ii —a) (ms— a) (w e— dl

This is ate st w hich an expe rime n te r ought to apply to his in ettame n t so as to find to w hat exte n t he may apply the fo rmulae , and

he w ill se e that w he n the te st is satisfacto ry the period o f the sw ingis appro ximate ly co n stan t. If

,as is o fte n the case , the sw ings are


by the tw o curvesand bise ct them in the po in ts A, B, C, &c., thenif the equatio n

a: a as

(w here c is aconstan t) be accepte dasasuflicie n tlyaccurate so lutio no f the differen tial equatio n given above , the curve jo in ing A,

B, C,

&c., the middle po in ts o f the o rdinate s sho w the time readings o f

the true defle ctio n s. To pro ve this — Le t time be co un te d fromthe first e lo ngatio n

,po in t 1 in the abo ve figure

, and le t G : f(t),le t

J ig

H.

merical values o f the sw ings to right and left o f aco n stan t ze ro ,then

K, so that K is alw ays po sitive and is the ratio o f the n u

f (n — 1 )Ti

t

Now a: f(t) CKT is the e quatio n to a curve passing

NOTES ON ELECTROLYTIC POLARISATION . 395

t

through allthe po in ts 1,2,3,4, &c.

,a: f(t) OKT=¢ t(say) Is

the equatio n to some curve passing through the po in ts 1 , 3, 5 , 7, &c.

ianda: f(t) C KT is the equatio n to some curve passing throughthe po ints 2, 4 , 6 , 8, &c. Le t us first co n sider

t

a: f(t) C KT

d z df Tx1

d t

_d t

+ C K xTlog. K

No w , sin ce the current passing through the galvan ome ter issuppo se d to be steadily dimin ishing it fo llo w s thata: f(t) must beacurve W ithout waves, something like fig. 2.

dftherefo re

dis always n egative ; and sin ce 0 andTare bo th po sitive ,

andlog. K 18 n egative , be ing the logarithm of aprope r fraction , itd a:

fo llo w s that(27

must be always n egative , and therefo re can n ever

be n ought. And since n e ither of the terms o n the right han d side

o f equatio n (1) can ever be infin ite6

5; can n ever be infin ite .

d 2

f T 1

d tC K

Tlog. K )?and from the gen eral

d ?

d t—2

— isalways po sitive and fin iteappearan ce of fig. 2 w e se e that

also . C KT%log. K)2

must be always po sitive and fin ite , there


can n ever be n ought n o r infin ity; therefo re

w f (t) + C Kfr

is the equatio n ofaregular curve w ithout po in ts of contrareflexia

and w ithout po in ts, at w hich .e is amaximum o r m in imum , therefore it must be very like the o n e w e have draw n through 1, 3, 5 , 7,&c., in fig. 1.

Fo r the same value of t,

and

Buta: f t is the equatio n of some regular curve , so also (as w ehave proved) is .T t

, therefore a: ‘l’ tmustalso be the equatio no faregular curve through 1

, 3, 5 , 7, &c. , and consequen tly mustbe some thing like the o n e w e have draw n in fig. 1. The refo re ,aregular curve draw n through A,

B,C, D,

and the middle po in tso f the differen ce s of the o rdinate s must be the curve a: f (t) , andtherefo re repre sen ts the true po sition o f equilibrium o f the spo t o flight at any momen t.

CURVES A B , A’

B’

,C C

’

.

In fig. 3 time is measured paralle l to the lin e 0 X, starting


time , then sudden ly discharged and in sulated. More light has be enthro w n upon this re semblance in more recen t experimen ts made

by us.

CURVES K H,K

’

H’

I,I’

J.

The liquid in w hich the platinum plate s w as immersed w as n ow

amixture o f distille dand ordinary w ater, n o acid be ing added, thedimen sio n s, &c. o f the platinum plates remain ing as befo re . K

sho w s the first galvan ometer reading about w hich w e have anycertain ty ; it repre se n ts acurren t of 00 00632 farads pe r se con d at12 seco n ds from clo sing the circuit. This reading w as o btain ed

(se e our method given abo ve ) from the se co nd, third, and subse

quen t exten sio n s of sw ing o f the n eedle . The first sw in g w as ex

tremely great, so that the fall o f current during the first 12 se condsmust have be en exce edingly great. The curren t falls to Hfarads per seco n d at 34 4; minute s from begin ning o f the experi

men t . At H the plate s w ere in sulated. K’

H’

repre sen ts the riseo f e le ctrometer readings during the first 34 ; min ute s. At H’

the

reading isalmo st exactly the same as that of the Danie ll’s ce lls employed in this experimen t. H

’

I represe nts the fall of e le ctr ome terreadings, the plate s be ing in sulated . At I (52 m in ute s from the

begin n ing o f the expe rimen t) the plate s w ere co n n e cted throughco ils

,having a re sistan ce o f ohms

,and the curre n t w as

measured . The time fall o f this curren t is partly sho w n in the

curve I’J. This curve sho w s curren t o n ascale 123 time s as greatas the scale o f the o ther curve s o n the she e t AB , DE,

KH,but the

scale for time remain s un changed. The first reading w hich w e

w e re able to de termin e w ith any accuracy w as farads perseco n d at 11 seco nds afte r co n n ection , and the sw ings o f the n e edleduring the se 11 seco nds w ere exce edingly great.Experime n ts having be en made o n po larisatio n w ith platin um

plate s, w he n the re sistance exte rnal to the vo ltame ter w as verysmall compared w ith that o f the vo ltame ter itse lf the platinumplate s w e re replaced by clean copper plate s, to se e in w hat w aythe results w o uld be affecte d . It w as found that w hile in aparticular case the curren t passing from o n e Me idinger ce ll thro ugh avo ltame ter, con sisting o f tw o platinum plate s immersed in o rdinary

NOTES ON ELECTROLYTIC POLARISATION. 899

w ater, w as dimin ished 90 pe r cen t. in n in e m inute s ; the curre n tfrom the same ce ll passing betw e e n tw o clean copper plate s at thesame distan ce apart as the platinum plate s

,and imme rse d to the

same depth in the w ate r,w as o nly dimin ished 9 per cen t. in 30

m in ute s, and the coppe r plate attached to the copper po le o f the

batte ry w as bro w n ed . With tw o iron plate s the diminutio n of

curre n t w as also ve ry slo w . The copper plate s w ere the n platin ise dw ith platinum te trachlo ride , but the rate o f dimin utio n o f the cur

re n t w as n o t fo un d to be much increased ; this w as po ssibly partlydue to the te nden cy the platinum had to run off. A copper and aplatinum plate w ere then tried

,and it w as fo und that w he n the

co ppe r plate w as the an ode (so that oxygen w o uld have be en de

po sited o n the copper plate w ere the w ater de compo sed) the po larisatio n w as practically the same as in the case of tw o clean copperplate s, but w hen the battery w as reversed

,the copper and platinum

plate s in the vo ltame te r having be en previo usly tho roughly clean ed,the n the falling off of the curren t w as (ro ughly) abo utas rapid as inth e case o f tw o platin um plate s. Next tw o copper plates w ere em

ployed, the o n e quite clean the o ther thoro ughly oxidised by previo us e lectro lysis

,and it w as found that w he n the clean coppe r plate

w as used for the cathode,and the oxidised o n e fo r the an ode in the

vo ltamete r, the po larisatio n w as ve ry rapid, hen ce sho w ing that anoxidise d coppe r plate acted n early as w e ll as aplatinum plate fo rthe an ode . Starting w ith the se re sults w e made a n umbe r of

expe rime n ts to find out w he the r the po larisatio n be tw e en tw o thickco ppe r w ire s, o n e o f them oxidised and the o ther clean

,lying n ear

o n e an o ther fo r abo ut o n e hun dred yards in the Co llege Moat, w as

sufficie n tly great to pro duce any co n siderable surface re sistan ce ,suchas w ould lead to an e w metho d o f submarin e signallin g . Fo r

such ascheme to pro ve succe ssful the po lari sing battery must haveaco n stan t e lectromo tive fo rce about eclualto that o faDan ie l], andit must have avery small in ternal re sistan ce co n seque n tly ; fo r theabo ve experime n ts w ith the lo ng w ire s, Thomso n

’s tray ce lls

,each

having plates ofabout thre e square fe e t area,w e re employed, w ith

re ce iving in strumen ts of verv small re sistance .

The results o btain ed w ere satisfactory, but w an t o f time , and then e ce ssity for obse rvatio n s o n alarger scale , have compe lled us to


po stpo ne the se experimen ts w ith the long w ires fo r the pre se n t,andin the mean time w e have be en making o thers, w hich have , ho w ever,adirect bearing o n the preceding.

Up to the pre se n t time our o bse rvatio n s had bee n co nfin ed toplate s

,o f w hich the lin ear dime n sio n s w ere n o t large compared

w ith the ir distan ce asunder. We n ow made expe rimen ts w ith tw oplatinum plates placed ve rtically in o rdinary w ater paralle l to o ne

an o the r,and about e ight inches asunder; the immersed areaof eachside o f each plate w as abo ut o n e and ahalf square fe e t. The

diminutio n o f current w as in allthe case s w e trie d comparative lysmall, and w e append alist o f the batterie s employed, arran ged ino rder o f e le ctromo tive fo rce .

Reductio n o f curren t.

Three batterie s in series, each of the first

tw o be ingfive Grove’s cells jo in ed paral

lel, and th e third consisting of six bi

chromate of potash cells jo in ed parallel 3 6 per cent . in 36 minutes.

Tw o batteries in series, each co n sisting o f

five Grove ’

s cells jo in ed parallel 38 per cent in 13 minutes.

Ten Grovc’

s ce lls jo in ed paralle l per cent . in 34 minutes.

Six old bichromate o f po tash ce lls jo in edparallel 16 per cent. in 1 ho ur.

On e battery con sisting o f ten Grove ’s

cells, and sixbichromate o fpo tash cells,alljo in ed parallel 73 pe r cen t. in 43 minutes.

On e porous cell(Danie ll) Inappreciable .

With the exceptio n o f the fourth battery,the six old bichromate of

po tash ce lls, w e find that the amo un ts o f the diminutio n s sho w n

above are , w hen calculated fo r equal time s, ro ughly speaking inthe o rder o f the numbers obtain ed by dividing the e le ctromo tivefo rce o f the battery by the batte ry re sistance .


4 . D disco nn e cted from the galvan ometerand the curre n t pro duced by C and Ameasured 62

5 . D reco nn e cted w ith the galvan ometer,but C disco nn ected, and the curre nt produced by B and D, measured 62

The n ext e xpe rimen ts w e re made to examin e the actio n o f C and

D,w he n

,in stead o f be ing placed in the hydrogen and oxygen ,

they had gase s depo site d o n them e le ctro lytically, in w hich casethe dire ct curre n t from C to D w ould be much mo re en ergetic.CC

’

,DD

’

(fig. are tw o platinum plate s immerse d in verydilute zin c sulphate , and w hich may be co n n ecte d dire ctly w ith aMin o tto ’

s ce ll, o r w ith agalvan ome ter G and re sistan ce co ilofohms.

Fig. 5 .

Aand B are tw o platinum plate s w hich w ere kept un der w ate r inavacuum fo r some time to partially remove any gas that m ight beco nde n sed o n them ,

and they w e re placed at the bo ttom o f the

zin c-sulphate W itho ut expo sure to the air. Whe n CC'

and DD'

w e re co n n e cted w ith the Min o tto ’s cell, DD

’

w as the an o de , CC’

the

cathode . We shall n ot,at pre se n t

,speak o f any phe n omenaof

charging, but o n ly o f tho se that o ccurred afte r remo val o f the

batte ry and co n n ectio n w ith the galvan ome ter and re sistan ce co ils.The curre n t from D to C w as fo und to be many time s increasedw he n A w as co nn ected to D by mean s o faplatin um w ire

,o r w hen


co nn ecte d w ith the po in t R , and w hen A,in stead o f bemg co n

n ected w ith D,w as co nn e cte d w ith C’

,the curre n t w as reversed .

In allcase s the curre n t dimin ished w ith co n siderable rapidity. Thesame phe n omenaw ere o bserved w he n the experimen t w as repeatedw ith B in stead o fA. This se t o f experime nts

,the refo re

,co nfirms

the results previously obtain e d , w he n the gase s in co n tact w ith theplate s w ere n o t depo site d e lectro lytically . Bo th Aand B w e re o f

co urse alw ays disco n n ected from DD’

and CC’

w hen the se latte rplate s w ere be ing po larised w ith the Min o tto ’

s ce ll . Co n tinue dre pe titio n of the experime n ts made the re sults le ss and le ss marked,

w as to have be en expected, sin ce A and B w e re n o lo nge r inthe ir primary n eutral state .

When five Min e tto ’

s ce lls in serie s w ere employed in stead o fo n e to pro duce po larisatio n ,

it w as fo und that the curre n t from D

to C w as dimin ished w he n A w as jo in ed by aplatin um w ire to D,

o r w hen B w as jo in ed by aplatinum w ire to C , andastill furtherdim inutio n w as pro duced if the se co n n e ctio n s w e re made simultan e ously. If

,ho w e ve r, B w as co n n e cted by mean s o f aplatin um

w ire w ith R then the re w as agreat in crease o f curre n t. When Dw as disco n n e cted from R

’

,and aplatin um w ire co n n e cted w ith R

m ere ly dips in to the liquid, the re w as acurre n t w hich w as manytime s in creased w he n this w ire to uched A o r B . S imilar re sultsw ere o btain ed w hen the galvan ome te r w as placed be tw e en D andR

’

,D co n n ecte d w ith the galvan ome ter, A disco n n e cted and the

platinum w ire co nn ected w ith B ’

.

It is po ssible that the reaso n w hy some o f the re sults obtain edw hen CC’

,DD

’

w ere po larised w ith five ce lls apparen tly differedfrom tho se obtain ed w he n o n e ce ll w as employed may have be e ndue to the plate s Aand B n o t be ing in the ir primary n eutralstate ,sin ce they w ere n o t heated n or placed in avacuum be tw e en thetw o se rie s o f te sts w ith o n e Min o tto ’

s ce ll and w ith five . It w as

n o t,ho w eve r

,tho ught advisable to repeat the abo ve te sts, but

rathe r to make mo re accurate o n e s w ith an improved form o f

apparatus w hich the above te sts show ed the desirability o f co n

structing .

In the mean time experime n ts w ere carried o ut to examin e howvariatio n of external re sistan ce and o f external e lectromo tive fo rce

2 D 2


w o uld influen ce the po larisatio n o f platinum plate s immersed ino rdinary w ate r. The plates w ere the same

,and at the same

distan ce apart, as in the first experimen ts o f allde scribe d at thebegin n ing o f this pape r. Curve s I. III . IV . and VI . and IX.

(fig. 6) sho w the time in crease o f the e le ctromo tive fo rce of

po larisatio n produced by abatte ry compo sed o f tw o old Min o tti’

s

ce lls,the exte rnal re sistan ce s in circu it, excluding that o f the

vo ltame te r,be ing re spective ly and

0 o hms ; thus in curve I . the e le ctromo tive fo rce o f po larisatio n atthe e nd o f five minute s from the starting o f the po larising curren t

is sho w n by the o rdinate AB,the time be ing de n o ted by the dis

tan ce 0A measured from O.

The method o f making the eXpe rin Ie n ts w as simple : A co il ofkn o w n re sistan ce , toge ther w ith ade licate reflecting Thomso n ’

s

galvan ome te r, be ing in se rted in the circuit w ith the batte ry andvo ltame te r, the differe n ce o f po te n tials o f the platin um plate s w asco n tin uously measured by the defle ctio n o f aThomso n ’

s quadran te lectrometer, w ith the e lectrode s o f w hich they w ere ke pt co n

n ected. Le t V be the diffe re n ce of po te n tials o f the platin um


vo ltame ter w ere re spective ly o hms. In

additio n to the yie lding o f the e le ctrometer suspe n sio n fibre s,caus

ing discrepan cie s in the value o f K,it is pro bable that the

assumptio n just made o f the co n stan cy of the vo ltame te r re sistan cemay also be an o ther cause o fpo ssible e rro r in the value s o f e . The

e lectromo tive fo rce o f the tw o Min o tto ’

s ce lls pre viously used w as

about thre e -quarters o fthat o fthe tw o po rous cells, Dan ie ll’s,used for

curves II. V II . X. and XI. If P be called the maximum e le ctromo tive fo rce of po larisatio n obtainable w ith alarge battery

, the n Pis greate r than E in the case o f the tw o Min o tto ’

s ce lls,n e ve rthe less

the maximum value o f e w ith the Min o tto ’s ce lls is less than E

,

except perhaps in curve IX. and this is probably due to w hat maybe called the dissipatio n o f po larisatio n be ing as greatas the Supplyafforded by the batte ry w hen the maximum is approached. The

curve s show in ave ry marked w ay w hy the charging o f avo ltamete r as aco n den ser is so ve ry differen t from the chargin g of

aglass co n de n se r, this differen ce be ing due (first) to the muchgreater dissipatio n in w ater than in glass, and (se condly) to the re

sistan ce o f the battery galvan ome te r and co n n ection s be ing com

parable w ith the re sistan ce o f the vo ltame te r,w hich n ever happe n s

in the case o f a glass co n de n ser, co n sequen tly curve IX. mo re

n early co rre spo nds than any o f the o the rs w ith the ~curve s, sho w ingthe productio n o f in ternal o r oppo sing e lectromo tive fo rce in aglassjar, w hich have be e n draw n by us from expe rimen ts pe rfo rmed w iththe flin t glass jar o f a Thomso n

’

s e lectrome ter, and w hich w illSho rtly be published.

The greate r approximatio n to w ards the right han d side o f the

figure 6 in the case o f curve s II . V II . X. XI . than in the case of

co rre spo n ding curve s fo r the tw o Min o tto’

s ce lls,isdue pro bably to the

e lectromo tive fo rce o f the batte ry in the former case be in g greaterthan the maximum o btainable e le ctromo tive fo rce o f po larisatio n .

The defe cts in the e le ctrome ter be ing mo re perceptible , the higherthe differe n ce o f po ten tials to be measured may cause the relativeappearan ce o f curve s II . VII . X . XI . to be mo re disturbed thanin the case o f the o ther curve s. W e have n o doubt, also , that w ithave ry accurate e le ctrome te r allthe curve s w o uld be ste eper at thebegin n ing.

NOTES ON ELECTROLYTIC POLARISATION. 407

The follo w ing expe rim en tsare aco n tinuatio n of tho se previouslyde scribed, made o fthe discharge betw een apo larised and an eutralplate . 0 , H, S (fig. 7) are thre e platinum plates immersedsymme trically in a large glass ve sse l co n tain ing distilled w ater .

The immersed areao f each Side o f each plate w asabout 60 squarece n timetre s and the re sistan ce be tw e e n any tw o o f the plates w as

ohms in the earlier expe rime n ts, and ohms in the

latte r o n es w hen the w ate r w as hydroge nate d. In each o f the six

experimen ts 0 and H w ere po larised w ith a n e w po ro us ce llDan ie l], fo r six min ute s

, 0 be ing the an ode , H the catho de, and S

kept at po te n tial n ought,and having n o co n n ectio n w ith the batterv

circuit except in so far as it w as in the liquid ; the battery circuitn o t be ing con n ected w ith the groun d

,n o curren t passed thro ugh it

during charging. At the e nd o f the Six m in utes the battery w asdisco n n e cted and tw o o f the plate s w e re in stan tly co n n ecte d thro ughthe po le s o f aThomso n

’s de licate refle cting galvan omete r w ith an

additio nal re sistance o f ohms in circuit to observe the dissipatio n of po larisatio n . Be tw e en each se t o f experimen ts allthre eplate s w ere short-circu ited un til they w o uld produce n o curre n tthro ugh the galvan ome ter. Curve s A

,B,C (fig. 8) sho w time

readings o f the curre n t in thre e successive chargings, the liqu idbe ing o rdinary w ater, time be ing measured ho rizo n tally alo ng OX,

CL be ing e qual to six m in ute s, and curre n t measured vertically ,


LA,measured alo ng alin e thro ugh Lat right angle s to OX, repre

se n ting acurren t o f 141 microfarads pe r secon d fl ow ing thro ughthe vo ltame ter.

asho w s the discharge curren t be tw e en 0 and Hb o Sc n S H

The w ate r be ing tho ro ughly hydrogenate d by bubbling hydrogengas through it fo r aco n siderable time , the experime n ts w ere re

peated ; D , E,F sho w the thre e charging curre n ts o btain e d in the

thre e successive case s


rubber tube MC, co n n ecte d w ith ame rcury reservo ir M,o pen to

the air, and w hich co uld be lo w e red in to apo sitio n M’

fo r pro

ducing avacuum in AB,as in aGe issler’

s vacuum pump . AB

w as clo sed w ith an air-tight co rk AD, thro ugh w hich passed atubeEF

,w hich co uld be tightly clo sed at the upper end. Thro ugh AD

passed also six thick coppe r w ire s,o f w hich fo ur are sho w n in the

draw ing a, b, c, d. To the e nds of each pair w e re jo in ed th e e ndso faplatinum spiral, made offin e platinum w ire o n e fo o t lo ng, so

that each o f the platin um plate s in our last experime n t w as n ow

replaced by aplatinum spiral. From E to G the space w as filledw ith distilled w ate r, and from G to M the space GBOM w as filledw ith mercury. When E w as clo sed and M low ered to M’

, the

leve l o f the w ater fe ll to H, and ago o d vacuum w as pro duced inEH. The platinum spirals w ere then made red-ho t in the vacuum,

by passing astro ng curren t from ato b, e to d, e to f, so as to freethem perfectly from gas , w hich more ex

po sure in avacuum ,even fo r alo ng time

,

w ill n o t do . It is in this particular that thisapparatus is an improvemen t o n that em

ployed by Prof. He lmho ltz in his expe rimen ts

o n po larisatio n,the impo rtan ce o f w hich

additio n w ill be se en from the re sults w e

obtain ed and w hich are n o w abo ut to be described.

A and B (fig. 10) Sho w the chargingcurve s obtain ed w ith o n e Dan ie ll’s ce llw hen the distilled w ate r w as pe rfe ctly fre edfrom air

,and the platin um spirals ke ep some

days in the vacuum EH,bu t n o t heated

,

Curren t is measured parallax to CY and

time paralle l to OK ,each re cko n ing from

Fig. 9 ,

O ; CY repre se n ts acurren t o f 00 000097

farads per se co n d passing thro ugh the vo ltame ter an d OX 8. time

o f e ightm in ute s.

a 6 repre se n t the curve s o f discharge w he n the batte ry is re

moved and the plate s o r rathe r spirals sho rt-circuite d thro ugh a


Thomso n’

s de licate refle cting galvan ome ter w ith are sistan ce co ilin tro duced in the circu it, the to tal resistance exte rio r to the galvan ome te r be ing ohms, time be ing recko n ed from O, the

in stan t o f discharge alo ng 0A,the scales fo r time and curre n t

remain ing as before .

Fig. 10.

C and c are similarly obtain ed curve s w hen the distilled w ate rw as tho ro ughly fre ed from gas and the platin um spirals w ere inadditio n made red ho t ; D and d w he n the w ate r and spirals w e re

tho roughly ae rate d.

E an d e , w he n the w ater and platinums w ere tho ro ughly fre edfrom air, but tho roughly saturated w ith hydroge n .


LIGHTNING CONDUCTORS.

In No . xn . vol. iv. of the Journal o f the So ciety o f Te legraphEngin e ers, there is ale tte r by Pro fe sso r Clerk Maxw e ll o n the

in tere sting que stio n of lightn ing co n ductors. His vie w s are morefully give n in apape r read be fore the British Asso ciatio n

,and

publishe d in Nature , Septembe r 28th, 1876. He state s that it is

n o t n e ce ssary to have any earth-co n n ectio n , o r to have atall conducto r w ith asharp po in t, but that aco n n ected system o f w ires

laid alo ng the edges o f abuilding w ill sufficien tly pro te ct it fromthe effects o f alightn ing discharge . It se ems at first sight thatthe reaso n ing is co rrect, based as it is o n the fact that w henelectricity is at rest every po in t in side aco nducto r co n tain ingn o e le ctrified bodie s is at the same po ten tial as the co n ductoritse lf, and also that even acage , o f w hich the w ire s are w ide lyseparate d from o n e an other, behave s like acomple te me talco veringin its scre e n ing actio n . But w e think n o theo ry de duced from

static phen omenacan be regarded as satisfactory w he n applied tothe inductio n phen ome nao f alightn ing discharge . The dischargeo faclo ud, w hether to o ther o bjects o r to Pro fe sso r Cle rkMaxw e ll’scage , is disruptive , and must be regarded (see Cle rk Maxw e ll’sEle ctricity,

” art. 231) as the commencemen t, passage , and e nd

o f acurre n t o f e le ctricity ; an d since , as is w e ll kn o w n , n o co n

ducting cage w ill scre e n a circuit from the effects o f currentinductio n , it is evide n t that an in stan tan e ous curre n t may passbe tw e e n tw o po in ts in side acage during alightn ing discharge inthe n e ighbourho od . Lo oking at the subje ct from astatic po in t ofvie w

,w e se e that w ith agive n e le ctric distributio n A o uts ide a

cage C there is alw ays such adistributio n o ver C as ke eps tw opo in ts

,B and D (suppo sed to have n o abso lute charge s) , at the

same po te n tial . If n o w there is acharge in A,acharge w ill be

produced in C , and B and D w ill be again at the same po te n tial.But w e w ould ask if the re is any evide n ce to pro ve that duringthis charge the con ditio n s o utside and in side the cage are such asto ke ep allpo in ts in side at the same po ten tial . Inde ed the chargein C is a co n sequen ce o f the alte ratio n in A, producing acertain


defle ctio n produced in the suspe nded co il by the stationary co ilwas

n ow accurate ly measured, and it w as found that there w as n o apparen t alteration in this defle ctio n , ce rtain ly n o t an alteratio n o f o n e

pe r cen t. , by the in troductio n ofaso lid rectangular blo ck o f copper30 ce n timetre s lo ng, 15 ce n timetre s thick, an d 15 cen timetre s high,be tw e e n the co ils, so as to fillup the e ntire air space be tw eenthem , and so that o n e co il w as comple te ly hidden from the o ther.

In fact the fre quen t slo w in terpo sitio n and removalo f the co pperblock, w hich w as place d o n acarriage w ith w o oden w he els for thispurpo se , produced n o visible effect in the actio n o f o n e co il o n theo ther.

III. The seco ndary co ils of tw o inductio n arrangemen ts w ere

j o in ed up in circu it w ith avery de licate galvan ometer in suchaw aythat the induced curren ts balan ced o n e an o ther and so that the

same curre n t trave rsed each primary co il. The o n e in ductionarrangemen t w as an o rdinary Ruhmkorff’s co il, the o ther co n sistedof tw o ho rse -sho e e lectro -magn e ts, placed end to e nd ; the co re of

each of the se ho rse-sho e magn e ts w as 8 millimetre s in diamete r,

and each leg o f each magn et w as furn ished w ith abo bbin o f w ire

3 ce n timetre s in diame te r, the length of each bobbin be ing 5 cen

timetre s, an d the re sistan ce o f each e lectro -magn e t 300 o hms.

No w it w as de te rmin ed w ith this de licate differe n tial arrangemen tthat the curren t in duced in o n e pf the se e lectro -magn e ts by asudde n reve rsal o f the curren t in the o the r w as n o t alte red by

Tgfiths

(00 5) pe r ce n t. w he n ashe e t o f coppe r, brass, o r zin c,225 square

cen timetre s in area,and o n e m illimetre thick

,w as in terpo se d be tw een

the tw o e le ctro -magn e ts so as to complete ly hide the o n e from the

o the r. Practically, therefo re , curre n t inductio n is n o t in the leastdimin ished by the in terpo sitio n o f ascre e n o f copper

,brass

, &c.

He n ce in the case o f abuilding surroun ded by acage , but unproVided w ith an e levated po in t and an earth-plate , since , w hendisharges are taking place in to the cage o r in its n e ighbourho odthe se discharge s are disruptive , the cage w ill have n o effe ct inpreven ting an induced disruptive discharge in side ; in fact th e o n lyw ay o f rendering an in ternal disruptive discharge impo ssible is bypreven ting alldisruptive discharge e ithe r n ear the ho use o n the

o utside o r through the me tallic o r o ther co nductors o f the ho use .

LIGHTNING CONDUCTORS. 415

No w w e w ish to po in t o ut that w ith the commo n method o f pro te cting abu ildin g from lightn ing w he n the po int taps the clo ud fo r thebe n efit o f the building and all bo die s in its n e ighbo urho od

,it

pe rfo rms this Ope ratio n slo w ly,an d disruptive discharge is impo ssible

w he the r w e imagin e that acloud come s from a distan ce anddi scharge s itse lf at the po int o r that the po in t and the earth aresubje cte d to are turn sho ck. It also perfo rms efficien tly the o fficeo f the pro po sed cage

,and is

,there fo re

,amo re efficien t pro te ctor.

It is probable , ho w eve r, that, Sin ce the po in t require s to be sharpan d the earth-plate in go od co n tact w ith the earth, any o rdinarylightn ing-rod w ill gain in efficien cy by be ing suppleme nted by acage .in metallic co n n e ction w ith it.W e have be en led to make the abo ve remarks by o ur kn o w ledge

that altho ugh perhaps ametallic cage may be ago o d pro te ctio n toapow der-mill it is n o t aperfe ct o n e , and that e ve n acomple tecage w ould n o t, as Profe sso r Cle rk Maxw e ll

’s letter m ight lead

o n e to suppo se , be abso lute ly satisfacto ry,also acage w he ther

comple te o r n o t is as go od apro te cto r as aw e ll-con structed lightn in g-rod.

Pro fe ssor Clerk Maxw e ll remarks that w ith acage ahouse maybe in sulated from the groun d by alaye r o f aSphalte . But if a

ho use be w e ll in sulated by avery thick layer o f dry asphalte , the n ,n egle cting the in ductive effe cts to w hich w e have referred in thispaper, and w hich are n o t affe cted by the absen ce o r pre sen ce of

acage , it is quite immate rial w he the r there is acage o r alightn ing-rod, o r any pro te cto r o f any kin d , Sin ce such ahouse isfrom the fact o f its perfe ct in sulatio n quite safe from damage bylightn ing.

W. E. AYRTON.

JOHN PERRY.

The Imperial Co llege o f. Engin e ering,Tokei, Japan .


EXPERIMENT TO SHOW THE DIRECTION IN WHICHTHE ELECTRIC SPARK TENDS TO TRAVEL.

If in to the se co ndary circuit o faRuhmko rff’s inductio n co il w ein troduce an extreme ly high re sistance

,such as that due to an inch

o f dry air, w e shall find,w hethe r sparks pass acro ss this in terval of

re sistan ce o r n o t,that th e co nductors o n e ither side are e le ctrified in

o ppo site directio n s by aserie s o f rapid pulsatio n s.

The ir re lative co nditio n is therefo re in many re spe cts analagousto that o f tw o co nducto rs highly charged w ith e le ctricities of

oppo site sign .

This can be verified by charging aLeyden jar from e ither ofthese co nducto rs and te sting the nature o f its charge by an ele ctrome te r o raB ohn e n berge r’

s e le ctro scope .

In this expe rimen t the o ppo sing co nductors w ere made to con sisto f brass plate s, each carrying ahemispherical kn ob an d aco n icalpo in t ; the po int o n the o n e be ing oppo se d to the kn o b o n the

o the r and vice versa. (Se e Ske tch .)The distan ce be tw e e n the se plate s is measured byascale and can

be varied at w ill.No w

,if the plate s be pre tty clo se toge ther, o n se tting the machine

in actio n aco n tin uous stream o f sparks w ill flo w acro ss be tw eenbo th pair o f te rminals

,that is

,at aband cd but if the distan ce be

gradually in creased it w ill be foun d that at a certain distan ce thestream o f sparks w ill cro ss be tw e e n o n ly o n e pair o f te rm inals

,let

uS say ab. If n e w the dire ctio n o f the curre n t in the primary co il,an d the refo re that o f the induced curre n t caused in the se co ndaryby its in te rruptio n

,be reversed

,it w ill be foun d that the Sparks

w ill pass o n ly be tw e e n the terminals 0 d.

It is assumed that in each o f the se case s the e lectrical te n sionis re lieved by the passage o f the spark from the po in t to the kn obn o t from the kn ob to the po in t— i. e . from ato b o r from d to o.

No w te sting the e le ctrificatio n o f the se plate s by the m e thod

befo re re fe rred to , it is fo und that in e ve ry case the plate fromw hich the sparks pass is n egative ly e le ctrified an d vice versa.


On the eve n ing of the 27th in stantave ry vio le n t storm bursto ver Para

,in fact the mo st vio len t I have se e n fo r se veralmo n ths,

altho ugh this place is n o te d fo r its rainfall.The ground-flo o r o f the ho use is o ccupied by the ofi ce s o f the

IVcste rn and Brazilian Te legraph Company, and the flo or abo ve bymyse lf and fam ily . Upo n the ro o f is asquare ro om

, kn o w n to us

as “the Observato ry. Roun d the ro o f o f this ro om run s agutter,from o n e corn er o f w hich is apipe that carrie s o ff the rain w ate r tothe ro of o f the kitche n

,the n ce to and under askylight, w here

there is alarge fun n e l-shaped rece ive r, thro ugh w hich the w ater

runs by a6-in ch zin c pipe to atro ugh or sink in the kit chen , madeo f the very hard w o od o f this coun try. The mouth o f this pipe isabout five in che s from the bo ttom o f the sink, and under it and inthe sink w as standing 3. large galvan ized iro n basin coveringan o ther zin c pipe leading to adrain in the earth. Whe n this basinis full

,abo ut tw o in che s o f the pipe w ould be under w ater. At

72 0 p.m . o n the above -me n tio n e d eve n ing, at w hich time thesto rm w as abo ut at its he ight

,I to okasmall galvan ized iro n basin

to dip o ut some w ater from the larger o n e w hich w as overflo w ing,but at the mome n t I made the dip the w ho le place se emed to be inablaze , and thre e treme ndo us reports w ere heard, While the flashesfo r the mome n t quite dazzled me .

The flashe s an d reports to ok place in the sink clo se by my hand(w hich I think w as just in the w ate r), caused, I suppo se , as thecurre n t discharged itse lf from the upper pipe to the side o f the

large r basin , w hich by the pipe leading to the drain abo ve re ferredto w as in co n n ectio n w ith earth . Immediate ly fo llo w in g the

above phe n ome na came a treme ndo us peal o f thun der, and allaro und me w as ape culiar vapour and stro ng sulphurous sme ll.Afte r the sto rm

,and w he n I had re covered from the excitement

w hich had much frighte n ed Mrs. Slater and an English se rvant,w ho w ere standing by at the time and w e re w itn e sses o f the e ven t,I fo un d the co rn er tiles o f the ro om 0 11 the ro o f out clean o ff by

the lightn ing in striking the rain w ater pipe ,alo ng w hich it had run

to the ro of o f the kitche n an d fun n e l-shaped rece iver alo ng thepipe , until it reached the space caused by my dipping w ith thesmalle r into the larger basin .

OBSERVATIONS ON A THUNDERSTORM AT PARA. 419

Tw o large ho le s w ere fused in the latte r, o n e very large n ear the

top o f the side,w he re

,in my opin io n , the charge w as re ce ived from

the pipe , the o ther in the bo ttom exactly o ver the pipe, w hich, as I

state d be fore,leads from the sink to the earth. The edge o f the

smaller basin furthe st from me isalso fused,and from the po sitio n

I he ld it I sho uld judge this part w as in co n tact w ith the fuse dpart in the large r basin o ve r the sink-pipe . But that w hich se ems

to me to be amystery,se e ing that I w as n e ithe r in the least hurt

,

n o r fe lt anything at the time , is the fact that the marks o f my

fin gers w here they he ld the basin are fused in to it,the fo ur finge rs

o utside,and the thumb in side . Ho w can this have happe n ed

w itho ut my fe elinganything ? I w as standing o n ve ry dry flo o ring,and so may say I w as w e ll in sulate d. This po ssibly w as ago o dth ing for me .

Afte r leaving the sink fo llow ing the pipe to earth the curre n t

se ems to have me t w ith oppo sitio n at a ceme n ted jo in t abo ut te lfe e t do w n , as the pipe is the re burst ope n ; also , at its en tran ce in tothe earth, alarge sto n e w hich rece ived the pipe is broken .

During this same sto rm the lightn ing split a large mango tre en o t far from this.

J. Sivew right, Esq .,

Secre tary So cie ty Te legraph Engin eers.

ON THE CORRECTIONS TO BE APPLIED TO THE

APPARENT RESISTANCE OF THE CONDUCTORAND INSULATOR OF A TELEGRAPH LINE WHENDETERMINED IN THE USUAL WAY BY WHEATSTONE’

S BRIDGE.

By 0 . B o om ,M.A.

Atten tio n has be e n frequen tly called to the impo rtan ce o f pro

perly re ducing the value s o f the co nductivity and o f the in sulatio no fasubmarine cable , o r o faland lin e , w he n the numerical re sultsobtaine d are influen ced by earth-curren ts

,o r w hen the lin e is im

perfe ctly in sulated . A comple te set o f fo rmulae have n o t,ho w eve r,

“i 2 E 2


I think be e n prin ted, and may be in teresting to the readers o fyourjo urnal.To e lim inate the effe ct of earth-curre n ts tw o me tho ds are in

commo n use . The first and simple st (as it requ ires n o calculation,and give s aco rrect re sult in allcase s) is that w hich is kn o w n asw o rking to afalse zero . Co n n e ctio n s are arranged as desired,and the re sistan ce s o f the differe n t branche s o f the circuit areadjusted to w hat is tho ught to be the ir correct value s.

The batte ry is the n applied , and the deflectio n o n the galvanom e te r obse rved . If o n reversing the battery n o change in thedefle ctio n is pro duced the adjustme n t o f the bridge is co rre ct. If

o the rw ise , the re sistan ce s are to be altered un til n o change in thecurre n t thro ugh the galvan ome ter is o bserved o n re ve rsing the

battery. Sho uld it be u nde sirable to reverse the batte ry current,

the defle ctio n o n the galvan ome te r is to be unaltered o n substitutingfo r the batte ry itse lfacircu it o f the same re sistan ce as the batterycircuit

,but w itho ut an e le ctromo tive fo rce .

Whe n the e le ctromo tive fo rce in the circuit,the re sistance 0f


The mo st co nven ien t fo rm o f formulaII. for this case is

” H M “-‘f)

Case IV .— ao n ly varying

,and co rre spo nding to co nn e cti ons in

w hich an in sulate d po le o f the galvan ome te r is co n n ecte d to thejun ctio n be tw e e n the tw o ratio co ils. Formula II . takes thefo rm

2rr’

B . e . (r — r'

)2

_r + 7

"

Case V .— b o n ly varying. For this case it is n e ce ssary to use

fo r ratio co ils tw o re sistan ce s n o t perman e n tly co n n ecte d as theyusually are

,and is in te re sting as be ing the o n ly case in w hich the

re sistan ce o f the batte ry is n o t alw ays invo lved.

Fo rmulaI . give s the mo st conve n ie n t result for this case . Fromit w e have

2bb’

+ o (b b’

)

(1) — 632(c— a)

b’

) B(b+ b’

c . (c — a) (b

[2bb'

c(b

2bb’

b + H+ ~

a

He re b and b’

are proportio nal to the apparen t co n ducting pow erso f the circu it w ith the tw o curre n ts

,and it is clear that the second

te rm van ishe s if a c.

The co n n e ctio n s are co nve n ie n t in experimen tal w o rk w hen ave ry high re sistan ce has to be de te rmin ed .

Again , if the cable is compared again st afixed re sistan ce , andthe ratio o f the re sistan ce o f the cable to this re sistan ce is measured

by aVarley’s slide

,tw o o f the quan titie s a b c vary

, but so that

the sum o f the tw o remain co nstan t.

CORRECTIONS OF APPARENT RESISTANCES, ETC. 423

Case VI — Let aand b vary , but so that

b = mp, c l— m .p

co rrespo nding to the more usual case in w hich o n e po le o f the

galvan ometer isattached to the sliding co n tact o n the slide co ils.The n

Case VIL— If o n the o ther hand the battery is attached to thesliding con tact w e must put

b= m p, a= l— m pb

’= m'

p, a'= l—m

'

p

1 — m 1 — m —m’

)

This formulacan n o t be put in amuch mo re co nven ie n t fo rm for

calculatio n . The co n n ectio n s have the advan tage that B e n ters

in to the expressio n divided by p , usually amuch large r quan titythan B .

If the battery re sistan ce is in co n siderable compared w ith allo therresistan ce s through w hich the curren t flo w s, B may be n egle cte d,and formulaII . take s the simple fo rm

W h ich applies to allcase s, and in practice is usually sufficie n tly

To preve n t any co n fusio n as to the mean ing o f the quan titie sa,b,c in this formula, it is sufficien t to observe that in allcase s 6

is the re sistan ce co il of w hich n e ither end is directly co nn ected toearth, and that if o n e po le o f the battery is to earth ais the re sistan ce co il, o n e end o f w hich is to earth, but if on e end o f the galva


n ome ter is to earth then ais the resistance co il w ith an end to

earth .

In the fo rmulajust give n it is assumed that o n e pair o f o bservatio n s are taken , and that the e le ctromo tive fo rce remain s co n stantbe tw e en the observatio n s. In practice this is n o t alw ays the case .

Here usually ase rie s o f observatio n s are taken alte rnate ly w ith thetw o currents and at n early equal in tervals o f time .

To reduce such aseries the fo llo w ing me thod is sho rter thanthat o f reducing each pair of observatio n s separate ly an d equallyaccurate .

Take an odd n umbe r o f o bse rvatio n s, say n . Le t 0 1 b1 01— a,

b, e, &c. an6”onbe the values o f ab c for the first se co n d

, &c.

last o bservatio n . Where oz1 bg, a“, the lette rs w ith odd suffixes

corre spo nd to value s obtain ed w ith on e curren t,andas a4 a l

are values obtain ed w ith the o ther curren t.

Calculate

fo r allthe observatio n s,call the se numbers AlA2

also calculate &c.

calling the re sults B1 B3 B then the mo st pro bable value- i + tA

IX2B ] B2 &c’ E

u-l 21313

Vario us plan s w ill sugge st themse lve s to any o n e usin g thisme tho d to re nder the n umerical w o rk as sho rt as may be .

If an o rdinary bridge is used w ith co ils in the ratio o f 10 1,

100 1,&c.

,and o n e variable re sistance

,it w ill be mo st co n ven ient

to make 0 the variable re sistan ce,and to ke ep aand b co n stant

thro ugho ut the serie s.

o f r is

clThe n AI B 1 be come

b&c. and

b

re spe ctive ly four referen ce s as to a bo ok o f logarithms be ingrequ ired to de te rmin e the pair o f valu e s. If slide re sistan ce s areused, the mo st co nven ient fo rm o f the expre ssio n is fo r Case VI.


lo ss by leakage through the in sulator, is w ellkn ow n . Atany po intdistan ta: from o n e end o f the cable , the po te ntialis given by theexpressio n

(2 as

As B e 1

and the curren tat the same time by

1m

[ X(A e2

lo is re sistan ce per un it length of co nducto r 7» ale ngth of cablesuch that the w ho le resistan ce of the co nductor w ould equal thew ho le re sistan ce o f the insulator

,and A B depe nd on the co n

ditio n s at the e nds o f the cable .

Le t R apparen t resistan ce of con ducto r of cable de termin edby any of the usual methods, and R

’

apparen t re sistance o f the

in sulato r.

By de termin ing A and B first, so that the po te ntial van ishes atthe distant end o f the cable , and then , so that the curren t van ishesat that po in t, and equating the ratio o f the po tential to the current

at the n ear e nd to R and R’

re spective ly in the tw o case s,w e find

that the true re sistan ce o f co nductor

and true re sistan ce of the in sulato r

2 s/R R’

In this fo rm the equatio n s are applicable to lo ng lan d-lin e s of

un ifo rm leakage , w he re the in sulatio n re sistance is n o t large com

pared w ith the re sistan ce o f the co nducto r .

In the case o f submarin e cable s it is sufficie n t almo st alw ays totake an approximate expre ssio n as be lo w .

Expanding the logarithm,true re sistan ce o f co nducto r

R

CORRECTIONS OF APPARENT RESISTANCES, ETC. 427

true resistan ce of in sulator

R'

(I 5 “

R’)

or mo re n early true resistan ce of conductor

B (‘true resistan ce o f insulator

(1 - eR, 445 3

—72as fl ees. XVII

In this form the equatio n s are applicable to the case w here thein su latio n resistan ce is apparen tly o n ly tw o or more time s that o f

the conducto r.

On the o ther han d, if the appare n t resistan ce of the in sulato r 18o n ly alittle greater than that o f the conductor

,an approximate

fo rmulacan be obtain ed in terms ofR B w hich w illthen be a

small quan tity.

R

ERis avery smallfraction , true resistan ce o f co nductor

sR{log. 4 log. RER} XVIII.

true resistan ce of in sulato r

log. 4 log. R’

B

The se expre ssion sare n o t so much simpler than tho se first give nas to make them of much value , and are on ly applicable w hen

R

};Ris so small afractio n that alike proportio nale rror in the

final re sult is of little co n sequen ce . It has been assumed in thesefo rmulae that the leakage is un ifo rm o ver the w ho le le ngth o f cable .

If this is n o t the case , avery con siderable differen ce re sults in theco rre ction to be applied.

In many cases of submarin e cables acertain length o f cable isat apretty un ifo rm temperature , the n alength in de ep w ater at


the lo w e st temperature , again alength in shallow waterat ahighertemperature , at the further end o f the cable .

In such case s the values o f the re sistan ce of the co n ducto r andin sulato r, as fo und from de te rmination smade at the tw o e n ds o f thecable , w ill differ, some time s by aquite se n sible amoun t.Suppo se the approximate temperature o f the cable to be kn o w n

at differen t depths, so that the approximate re sistan ce s o f th e co n

ductor and in sulato r are kn o w n also . Le t rl r, r8 be the e stimatedre sistance s o f the portio n s of the co nducto r in shallo w w ate r

, at

n ear end o f cable in de ep w ate r, and in shallow w ater again atthe further e nd.

Also le t Rl R, E3 be the e stimate d values o f the re sistan ceacro ss the sheath of the insulato r along the same po rtio n s o f cable

,

and r the to tal re sistan ce o f the co nductor o f the cable,fo un d in

the o rdinary w ay, R o f the in sulato r.

Then true re sistan ce o f co n ducto rrg+ r

3+

r3 + r2

nr—g — g+ :

8

R1

r n

and true re sistan ce o f in sulato r

)(r + 23 .

R1 R R R RR R R

very n early,assuming that the to tal in sulatio n re sistan ce o f each

po rtio n o f the lin e is much highe r than the re sistance o f the co n

ducto r. If the re sistan ce o f the con ducto r thus co rre cted give s amean temperature for the cable e qualto that assumed in e stimatingr,r, ,& c.

,there is pro o f that these value s are n o t far w ro n g. If

it do e s n o t agre e o the r value smust be tried un til some are fo undthat do agre e . Whe n the values o f the temperature are foundpre tty co rre ctly

,the in sulatio n re sistan ce s R I R2 R, can be mo re

n early e stimated, and from them the to tal mean in su latio n o f the

cable at any standard temperature .

Fo rmulae VIII. and IX. are fo und by expanding the expo n e n tialexpre ssio n s analogous to tho se in I . and II .

The approximate fo rmulae XI . XII . XV . XVI . are sufficie n tlyaccurate fo r allcable s insulated w ith gutta-perchao r india-rubber.


XXI . and XXII. the values o f z andafrom equation s XXVI , theco rre spo nding quan titie s fo r the third se ction are found.

In allthe se equatio n s it is assumed that the leakage is un ifo rmo ver each se ctio n Of lin e

, acon ditio n o f course On ly very approximate ly attain ed in practice .

Fo rmulae I. to XXI. co n tain , I think, expressio n s (in co nv en ien tfo rms fo r numerical calculatio n ) for allthe co rrectio n s that are tobe applied to te sts fo r the co nduction and in sulatio n o f ate legraphlin e (suppo sed fre e from iso lated faults in the case o f equatio ns XI.to XXI .)With regard to the e ffect o f agive n un ifo rm leakage o n the

signals re ce ived at the furthe r e nd o f the lin e , in the case o f anyland-lin e '

in w hich the e le ctro static capacity may be n egle cwd, it

appears that if C is the curre n t e n te ring such alin e , and C’

the

curre n t flo w ing o ut at the furthe r end at the same .time— R be ingthe apparen t in sulatio n re sistance o f the lin e , and r the apparen t

re sistan ce o f the co nducto r— then0

’

R’

R

O-

R, XXVII.

This ve ry simple expre ssio n give s the ratio in w hich signals aredim in ished o n any lin e for w hich the value s R and R ’

foun d byo rdinary te sts are kn o w n .

Fo r lin e s in w hich the to tal in sulatio n re sistance is many timesgreater than the to tal resistan ce o f the co n ducto r, it w ill be sufficie ntto take

XXVIII.

o r more n early

XXIX.

expan ding as usualClearly XXVIII is accurate w ithin 1 pe r ce n t. fo r value s of

I

n o t less than 5 , and XXIX. fo r value s o fR

n o t less than 3 .

The fo llo w ing sho rt table may be in te re sting as giving age n eralideao f the amo un t o f curre n t that is lo st o n lin e s w hich givecertain te st value s.

CORRECTIONS OF APPARENT RESISTANCES. ETC. 431

Co lumn A. co n tain s the ratio of the apparen t resistance o f the

lin e w he n the distan t e nd is in sulated to the appare n t re sistan ce o f

the lin e w hen the distan t end is to earth .

Co lumn B . co n tain s the proportio n o f the curre n t e n tering thelin e that flo w s o ut at the distan t end w he n that e nd is to earth .

I t is here sup

po sed that thc distan t end o f the lin eis in direct co n n ec

If the curren t, in

able resistance , thecurren t flow ingthrough th e in strumen t w ill clearlybe sen sibly dimin ich ed.

If w ith the abo ven o tation w e furtherput S the resistance o f the instrumen tat the far endoi the lin e , than theratio o f the curren tthrough the instrumcn t to the curren ten tering the lin e

R’ aRI

8

o w ing that the

effect o f the re

sistance o f the instrumen t is to di

min ish the rece ivedcurren t by afract i o nal am o u n t

n early equal to theratio that th e re

the lin e , suppo singthe resistance o f

the instrumen t lessthan that o f the

lin e in sulato rs.


ON THE MAGNITUDE OF THE SIGNALS RECEIVED

THROUGH A SUBMARINE CABLE WITH VAR IOUSCONNECTIONS AT EACH END,

AND THE BEST RESISTANCE FOR THE RECORDING INSTRUMENT.

By C . Hocxm,M.A.

SirWilliam Thomso n has given the complete the ory of the law s of

the variatio n o f the curren t in asubmarin e cable w he n n o re sistanceis in circuit at e ither end, and atable Of the numerical value o f the

curren t pro ducing a signalat the distan t end of the cable underthese circumstan ce s w ill be foun d in apaper by Prof. Jenkin on

submarin e cable s. The obje ct of the pre se n t paper is to de te rmineho w far the se values are alte red w he n re sistan ce s and co n densersare in circuit at o n e or bo th e nds of the cable .

The fo llo w ing is the mo st symme trical so lutio n I have fo un d.

Assume the co nn ectio n s at the en ds o f the cable tb be as in dicatedin the diagram .

The se co n n ectio n s w ill include allcase s o ccurring in practice .

Fo r if re sistan ce s o n ly are in circuit at e ither e nd w e have o n ly to


Then the know n equation o f po te n tialis

d% dv

8? d t

doand let:

day

The co nditio ns at the sending e ndare foun d to be

a.’

dgv B,

(i t) (Y,

dv 12

2ans‘

dx dt ani n dt (”

RV V 811! 2” t

and at the rece iving e nd

a (M 8 dc 7 dc

932 3 dz dt+an dw 2729 di

8” O

The so lutio n given by Fourier suited to the case in question

1) ea“ ((A sin (2t anm) B co s (2u

gt and?»(A

’

sin (2t anr ) B’

co s (2n2t — an :c)

A B,A

’

B’ have to be de te rm in ed so as to satisfy equations

4 and 5 ide n tically. Substituting fo r v in 4 and 5 its value from 6,and equating to O, the co efficie n ts o f sin T and co s T

,A B

’

A’

B’

are de termin ed . The n the se value s substitute d in the value of

x dxfrom equatio n 3

,give the value o f the curren t at the po in ta',

and if x is made equal to O the curren t at the re ce iving end

called F.

Put — a+ ,3 — 8,

e’

f,

a— B — S, 9

’

k,

e2 + f2

fl + ege9

+ f2

an VW WHY“(1

MAGNITUDE OF SIGNALS, ETC . 435

Where

G a“) (N 9 M2) 0

2 2 (Mt’

X1I.) sin 2L

2 (MU

an!) co s 2L

and II . is acomplex functio n of 7xp ,N a

’

,&c. w hich I do n o t give

as it is n o t requ ired fo r the purpo ses o f this paper.

‘ Equatio n s9 and 10 are exact, an d e nable us to find the maximum value thecurre n t reaches at the end o f asubmarin e cable un der the con

ditio n s stated above .

In the practical case some simplificatio n s can be in tro duced.

First. The e le ctromo tive force o f the batte ry do e s n o t varycon tinuously like the fun ctio n sin T

,but has agive n

co n stan t value fo r ace rtain time,and the n sudde n ly

alters to n o thing, o r to an equal n egative value .

Secondly. The cable be ing w o rked at the rate at w hich lo ngcable s are o rdinarily w o rked

,the value o f c is very

large,so that the first te rm in G is much larger than

the remain ing terms,and fo r o ur purpo se it w illbe suffi

cie n t to co n side r the n umerical value o f this term o n ly.

When the se co n d co nditio n just give n ho lds, the first co n ditio nin crease s the value o f the re ce ive d curren t in the proportio n o f

4 qr n early, and w e have to a sufficie n t degre e o f accuracy in

practice

From equatio n s 9 and 10, w he re— 27 (a— B)

+ 28 (a— B)

The gen eral expressio n isK

ai‘

s}= c (A ,

co s (T— L) A,sin (T— L)) -

1

6(B

,co s sm

W he re2A

;2 70

3

2A,= (x

i -Fai — l 2 7W

2Ex= ( 2 7W

2B 2 A)!

2 r 2


N and p.’

are the same fun ctio n s of a’

, B’

,vy’

,8’ as A.and aare of

a,B, 7 , 8, and aand B are defin ed by e quatio n sAllre sistan ce s an d capacitie s are here expre ssed in abso lute

measure . It w ill o n ly be n e ce ssary to remember that o n e Ohm is

107 in me tre-se co nds, o n e micro farad is 10 * ‘3 in me tre -se co n ds.W e w ill n o w put equatio n (17) in aco nven ie n t fo rm fo r the dif

fore n t case s o ccurring in practice .

CASES I. AND II .

No conden sers used.

Here there is are sistan ce at the se nding e nd,viz . the resistance

o f the battery, and at the re ce iving end the re sistan ce of the re

co rding,in strumen t.

W e therefore put R R’

s s’

O and r and r’

fin ite .

cc,8 cc

,w hile?

a

:r

.

If w e put

Andafte r reduction s

F V 2 J 2 an 1 1

«R J pn (p 1xx a?“ e

Could bo th the re sistan ce s be n egle cted w e sho uld have2 J 2 an

ck

This is the expre ssio n tabu lated in Pro fe sso r Jenkin ’

s pape r,in

w hich an arbitrary un it o f time is adopted,o riginally i ntro duced

by Sir William Thomso n for co nve n ience in calculating th e valueo f the serie s expre ssing the law fo llo w ed by the curren t arrivingat the distan t e nd o facable .

F = V

CASES III . AND IV.

Co nden ser at o n e e n d o n ly .

Le t co nden ser be at rece iving e nd. There w ill,as be fo re , be

tw o re sistance s— the batte ry and the galvan ome te r.

Then r’

r and s are fin ite,R

’

s’

Oand R co .


Equatio n s 14 to 21 give the value o f the maximum currentre ce ived at the end o f the lin e w hen asimple harmon ic variation of

po te n tial o ccurs at se n ding end.

If the batte ry has acon stan t e le ctromo tive fo rce , the size of thesignalp roduced by co n tacts battery , earth battery , earth, &c. is found

by multiplying the se expre ssio n s by 4 7r,o r 12 73 n early.

To illustrate the se fo rmulae w e take an umericalexampleCo n sider acable kn o ts in le ngth w ithare sistan ce o f 3 ohms

per kn o t and acapacity o f O4 micro farads per kn o t,malgrr “273

—

6L an l

r T.

Further,le t the rate o f sig nalling be N w o rds perm inute ,

60and JN°

IfN 10, by n o mean s agreat spe ed fo r such acable

,0 o r e

“

become s large , and o ur approximatio n s fo r I‘ are se e n to be prac

tically sufficie n t.

CASE I

Le t agalvan ome te r o f 3 000 un its be in circu it at o n e e n d o f the

lin e and abatte ry o f 75 un its at the o the r,the n in equatio n 14

“7” £275 r L’

2 88 ./N’l n early.

1c te l p p

1_1_

Or the re sistan ce o f the galvan ome ter reduce s the signals n earlysix time s.

To find the e ffect Of the battery put r 75 ohms,

AT) ?0 91 .

Or the re sistan ce o f the batte ry,w hich is o n ly 1 pe r ce n t. o f the

re sistance o f the cable , reduces the signals 9 per ce n t. and the tw ore sistan ce s toge ther reduce the curren t abo ut time s .

Next, suppo se the galvan ome te r to have are sistan ce o f 500 ohms,

MAGNITUDE OF SIGNALS, ETC. 439

ren t is therefore re duced to n early 06 o f its maximum value .

The re lative sen sitive n e ss o f the tw o in strumen ts is as 3000

J 5OO o r as l, and the size o f the signals re ce ived o n the tw o

in strume n tsas 5 9 x 0 582,o ras Z 1, show ing that o ther

things b e ing the same the galvan ome te r o f 500 ohms resistan cegive s larger signals than o n e o f ohms in the propo rtio n o f

10 7 n early.

To de termin e the best resistance for the galvan ometer w e must

make

o r sin ce p varie s as r

p,(1; amaximum,

o r 2p-

12,amin imum

,

P

O‘707.

Whe nce r 55The rule in w o rds is there fo re- F ix o n the n umber o f w o rds pe rm in ute like ly to he usually se n t o n the lin e .

Multiply the numbe r o f w o rds per m in ute by the to tal capacityo f the cable expre ssed in microfarads, and the pro duct by the to talre sistan ce o f the co n ductor in megohms.

Extract the square ro o t o f the triple pro duct. The re sistan ce o f

the galvan ome ter should be time s the re sistan ce o f the cabledivide d by the square ro o t already found .

From this it appears that fo r acable o f give n w o rking spe e dthe re sistan ce o f the galvan ome te r should be propo rtio nal to the

re sistan ce o f the conducto r ; thus the best galvan ome te r fo r alin e


w ith aco re 400 lbs. copper per kn o t has amuch lo w er re sistancethan o n e be st fo r aco re o f 107 lbs. per kn o t, the the o re ticalspeedo f the tw o lin e s be ing the same .

CASES III . AND IV .

The se are case s mo re gen erally realised o n alo ng submarinecable w here earth curren ts n ece ssitate the use o faco n de n ser at o n ee nd o f the lin e at least.The fo rmulasho w s at o n ce that the curren t at the distan t e nd of

the cable o n ly approache s to the curre n t re ce ived w he n n o co n

de n se r is in circu it as the capacity o f the co n den ser approaches

Neglecting re sistan ces in the first in stan ce the co nden ser dimin ishe s the curren t in the ratio o f

9

(1 + q)2 o 1. Where 9 x skl

Taking the n umerical case be fo re used

X 8 X p = 2 '53 8 p

first,if s 100 micro farads

,01

°

3 p x x 1010

9 n early,1 1 2 1 ° 1+

4?Q4 4 $30 3o r the signals are dimin ished time s.

If w e suppo se the co nde n se r to have 210 m icro farads capacity, 910

256 g n early.

It appears the n that if the re sistan ce Of the batte ryandalso o f the

re ce iving in strume n t is ve ry small, acapacity o f 210 micro farads

give s four-fifths o f the maximum curren t that can be re ce ived

w ill n early equal4,and the ratio 4


Or, since p is proportionalto r,

2p 29 aminimum.

Whence V

Or, if p s and S are expre ssed in Ohms and micro faradsspe ctively , the resistance o f the galvan ometer should be

293000

Ns’

Where N number o f w ords se n t per minute ,I

3 capacity o f the co nde n ser in microfarads,I

p to tal resistan ce o f conducto r o f cable in ohms,

S’

to tal capacity o f cable in micro farads,r

’

re sistan ce o f galvan ometer in ohms,

suppo se , as befo re ,N 10 3

’

p

293 J l (27V)?2 293 x «4774 900 Ohms n early.

As a seco nd in stan ce le t the cable have the same w o rkingspe ct but le t the core have are sistan ce o f 12 ohms pe r knotin stead o f 3

, and le t the capacity be 0 3 m icro farads per kn o t.Then , as befo re , S

’

p’

w hile p’ become s

n early,


Furthe r, if the galvan omete r had its best re sistan ce , the size o f

the signals w ould be proportio nal to

If the dire ct me tho d of Signalling had be en employed, thelarge st signals o btainable w ould have be en proportional to

E7 22an

a (J 2

i s)The last expressio n is alw ays greater than the fo rmer, o r the

m e thod of signalling w ith condensers is less sensitive than that ofs ignalling directly in allcase s.

Case V. Here aco nde n ser at bo th e nds Of the lin e is alw ays incircuit. This me thod has some advan tage s over allo thers

, and it

w ill be w orth w hile to examin e the numerical value s mo re clo se ly.

First, it is evide n t that the battery resistan ce should be as smallas po ssible and should n o t exce ed o n e pe r cen t. Of the re sistan ce o f

any cable o f con siderable re sistance .

Se co n dly, the to tal capacity o f co nde n sers available should beequally divided be tw e en the tw o ends o f the cable .

The n , if the battery re sistance is n o t larger than that state dabo ve , w e have size Of signals rece ived o n agalvan omete r o f re

sistan ce r proportional to

Or, if 9

M

AS befo re M is amaximum w he n


Using the same n o tation as befo re ,cp s/N

s/S?’

2a = 21 9 4/s

q

+ 21 98

9nThe min imum signal pro duced by a do t co n tact w ill beto that pro duced by the batte ry acting dire ctly through the galvan ometer

,and such an externalre sistan ce as w ill make the to tal

re sistan ce Of the circu it Q.

Where

K'

s/2e

l6 7ran

1 + q)’

Or, if furthe r1 (52+m2

1 E x/2eanl

16x

n an

Or,adopting the same n o tatio n as befo re fo r ohms and microfarads,

QE'

i n Ohms.


Example . Value o f r In ohms.

I . 790

11. 488

III . 640

Iv . 942

v . 626

v1. 780

VII . 1245

VIII . 1465

IX. 1418

x. 7 17

This table gives the approximate value of the co n stant of the

galvan ome te r used fo r Signalling o n the differen t lin e s co n sidered,the deflectio n produced by the smalle st signal (like the last do t of

the“

figure 5 ) be ing taken as the un it defle ctio n , and also the

be st value fo r the resistan ce of the galvan ome ter. It w ill be se en

that the re sistance o f the galvan ome ter is gen erally less than thatusually employed.On agiven cable the re sistan ce o f the galvan ome te r should be

le ss, as the w orking spe ed is greate r. It w ill therefo re be best toadjust the re sistance o f the galvan ome te r fo r the average spe ed of

w o rking rathe r than fo r the maximum spe ed,and to have the

galvan ome te r co il divided in to tw o o r thre e parts,w ith separate

te rm inals.

The pre ceding fo rmulae nable s us to estimate the Size o f the

min imum signal w hatever co n n ectio n s are used and w hateverre sistan ce s are in circuit at e ithe r end o f the lin e .

It is also clear from the se figure s that every care should be takenin the man ufacture o f “

speaking galvan ome te rs ; the magn etsmade o f carefully se le cted ste e l , the mirro r as light as po ssible , andthe galvan ometer co ilo f the proper fo rm.

Hitherto the size o n ly o f the signals has be en co n sidere d. The

gen eral formula9 give s an expre ssio n by w hich the shape o f the

signal , produced by sudde n ly raising the po ten tial at A, o rputting

0 11 the battery, can be calculated. If w e w rite that e quatio n in thefo rm v

y =f the n fo r a sudde n fin ite in crease Of po te n tialw eshall have


Ifv=f <r> 4f (3°r) 4M ? ) &c.

and by making 7 large compared w ith h cl2 the approximation maybe carried so far as desired, but the serie s converges ve ry slow ly

‘T

w hen m is greate r than un ity, and the pro cess w ould be very

tedio us. I do n ot know how to put the so lution in aco nven ien tform for numericalcalculatio n .

How ever, in o n e very importan t case , an approximation can be

o btain ed as fo llow s — If co nden se rs are employed bo th for sen dingan d fo r rece iving and of capacity small compared w ith that o f the

cable , it is clear that the curren t w ill n o t be very much alte red byasmallin ternal resistan ce in the co n de n ser. In fact, in stead o f a

con de nser w e may suppo se aSho rt length o f cable to be used fo rsen ding and rece iving. This case so lved leads to ase rie s co nverging rapidly.

Imagin e acable of infin ite length extending in bo th directio n sfrom its ce n tre 0 , divide it in to lengths OA,

AB,B C

,C D , &c. ,

in o n e directio n , and in to equal divisio n s OA’

, A’

B’

,B

’

C’

in the

o ppo site dire ction , an d le t

AA’ = B C DE B

’

C’

D’

E’

Le t 2Abe th e length of each o f the first series of segments, and2 lthat of the se cond series.

Le t the first series of sectio n s be charged to the potential

lVl 7x

an d the seco nd to the po te n tial Vl

There w ill be as much po sitive e le ctricity as n egative e lectricity


in the cable , and fi°

om the symmetry it is eviden t that n o curren tw ill flo w acro ss the middle po in ts of e ither of the segmen ts

,and

the distributio n o f e le ctricity and curren t from the middle po in t ofany segmen t to the middle po in t of the adjo in ing segmen t w ill bethe same as if this po rtio n w ere de tached from the cable , the e nds

in sulated, and the po rtio n o f the cable charged as first de scribed,

viz .

, ale ngth 8 to po ten tial V li 7» and the remainder to po ten tialit.Vl x

The curren t w illmo re over be the same as if the outside o f the

cable fo r alength 7» w ere low ered to po te n tial — V , and the remaining length unalte red in itially.

This is Thomso n’s me tho d of e le ctrical images. Applying

Po isso n ’

s expre ssio n fo r discon tin uo us fun ctio n s,the o riginal dis

tributio n o f po te n tialin the infin ite cable is repre se n te d by

—1-f f ¢ (v)) co s w (v— .v) dv dw

and the distribution o f po ten tialat time t by— w 9 t

co s ww ( .v— .v) e . dv dw

Where (P(v) is to be made equal to V w hen 7) lies be tw e en

7x1 7s) and (2 n l 2 7z — 1b )and t° — V

z+ x

w hen vlie sbe tw e e n + (2n l 2 n la) sna 2 n 1 1+ 217 — 170fo r allin tegral value s Of n , 0 to co .

In tegrating equatio n 2 w ith regard to so w e find


tho se o f the traced curve o n any abscissaare the ordinate s of the

signal . The curve co rre spo nding to the se o rdinate s having beendraw n , the effe ct o faseco nd signal is fo und by supe rpo sing thecurve for the se co nd signal or that o fthe first. In this w ay the curves


se co n d Spe ed w ill be fo und to be n early the speed employedgene rally o n lo ng cable s ; it co rre spo n ds approximate ly to

9 w o rds pe r minute o n the Fre n ch Atlan tic cable ,15 1865 cable ,10 In dian cable s,9 Chinacable .

The the o re tical curve s are very similar to som e re co rder slipsthat I have se e n from the Sue z

,Ade n , and o ther cable s.

Curve s IV . V . V I . V II . (fig. 6) sho w the alte ratio n in the Shapeo f the signal caused by asho rte r o r lo nge r batte ry co n tact, the

spe ed be ing the same as in curve III . In IV . the batte ry co n tact is

0 0 193 al2,the earth ale ; in V. battery is 0 0174 , and earth

in V I . the batte ry co n tact is 00 155 al’, and the earthal9 ; in V II . the battery co n tact is 00 166 alz

, the earthalg.

It must be remembe red that the se curve s are the limiting curvesas the se nding co nde n ser is dim in ished. The fo rm o f the signalso n are co rde r pape r w ill diffe r some w hat

,bo th o n acco un t o f the

large r co n de n se r used and the visco sity o f the in strume n t itse lf.Re turn ing to the equatio n giving the approximate law o f the

e n te ring curre n t. It give s the curre n t e n te ring as in fin ite at thefirst in stan t

,because the re sistan ce o f the batte ry has be e n n eg

le cte d, but the to tal quan tity o f e le ctricity that has e n te re d is givenas fin ite as it sho uld be . To find the to tal quan tity o f e le ctricitythat has e n te red the cable in time t w e have o n ly to in tegrate thee quatio n , and w e find the quan tity (Q) give n by the equatio n

tl — 3wj e :lz

lw he re z 18 w ri tte n fo r

X

The value o f the un in tegrate d e xpre ssio n is give n in the tablesaccompanying the article o n the The o ry o f Probabilitie s in the

En cyclopaediaMe tro po litana, and is to o w e ll kn o w n to requireco n side ratio n he re .

The fo llo w ing table gives(P) the propo rtio n o f the w ho le charge

MAGNITUDE OF SIGNALS , ETC . 455

en te ring the cable that has e n te red at the time 7° from the com

me n cemen t o f the signal . 7° is equal to -

t

ah”.

Value o f

‘8525

The curve co rre spo nding to the se n umbe rs is sho w n in figure 1w he re I 7 is apo rtio n o f the curve , the scale o f time be ing such

that the distan ce be tw e en each o f the thicker vertical divisio n sre prese nts the in te rval 7° o r to tal re sistance x to tal capacity of a

len gth of cable , such that its capacity w ould e qual the capacity of

the se nding conden ser,and IW is the same curve , the scale fo r

time be ing o n e -te n th o f that just give n .

The fo rm of the curve is peculiar,it rises very rapidly fo r small

valu e s o f 7° and ve ry slo w ly for larger value s.

This curve is in te re sting in the the o ry of duplex te legraphy.

T U,fig. 1

,is acurve calculated from equatio n it sho w s the

rate at w hich the curren t from the co nden se r e n ters the cable . The

scale Of time is o n e quarter that give n above fo r curve I W , so

that each‘

of the thicker vertical divisio n s are suppo sed separate dby an in tervalaThe o rdinate s are pro po rtio nal to 4 J 71

° x o r 4 J 71° x the


curren t that the battery w o uld main tain through are sistan ce equalto the re sistan ce of a po rtio n o f the cable o f w hich the capacity w ould equalthe capacity of the se nding co nde n se r.

The fo llo w ing table give s the value o f the curre nt e n te ring thecable at vario us in tervals .o f time .

TABLE OF VALUE OF CURRENT ENTER ING CABLE FROM SMAL L

SIGNALLING CONDENSER .

Value o f

The accompanyingtable give s th e valueof 7 fo r vario us valueso f q o r aa’. The

un it o f curre n t is the

curre n t that th e bat

tery co uld main tain

thro ugh a le ngth of

cable th e capacity of

w hich w o uld e qualthecapacity o f th e send

ing co n den se r, w hich

is suppo sed a very

small fractio n o f the

to tal capacity o f the

cable .


the re sistan ce in the circuit AB D is the resistan ce o f acable , eacho f the re sistan ce s r, , r

3 are half the re sistan ce o f the cable , and

the capacitie s o f the co nde n se rs are re spective ly the capacity o f the

g,47

5, 97

; &c.,the n the curre n t in A B isat each

in stan t equal to the curre n t e n te ring acable .

This sugge sts the be st arrangeme n t fo r duplexin g a sho rt cableo r lan d-lin e w or/ced w itho ut conden sers .

Tw o,thre e

,o r mo re co nde n sers in multiple are

,the re sistances

leading to them the same for all,and the ir capacitie s dim in ishing in

the pro po rtio n o f the re cipro cals o f the square s o f the o dd n umbe rs.

The to tal capacity in an infin ite n umbe r o f co nde n se rs w o u ld be

2 0 1 l 2 e l77°2

7-

6

cable divided by

o r o n e-third the capacity o f the cable .

In practice the re sistan ce o f A B,the re ce iving in strum e n t, w ill

be co n side rable , an d this w ill alte r the law some w hat, but the

dire ctio n to comme nce in ge tting a balan ce is that state d,afew

co n de n se rs in multiple are , n o t in se rie s.

If co nde n se rs are employed at bo th e nds, w e have se e n that thefo rm o f the expre ssio n is to tally diffe re n t

,and it w o u ld be n e ce ssary

to calculate the pro pe r value s o f C ] , C, , &c.

,so that the total

quan tity that had e n te red the cable at vario us in te rvals (the inte rvals must be asmall pro po rtio n o f the time o f vibratio n o f the

re ce iving in strume n t n e edle ) sho uld equal that give n by curve

I W at the same in stan t.

(ERSTED ’S DISCOVERY OF ELECTRO-MAGNETISM. 459

The vario us cause s o f disturban ce above -men tio n ed,and the fact

that the curve is o n ly appro ximate w hen the co nden se r is smallcompared to the to tal capac ity o f the cable , w o uld alte r the value s o fC an d r

,so that in practice it w o uld be n ece ssary to find by trial

th e be st arrangeme n t starting w ith the the o re ticalarrangeme n t asthe basis. The artificial cable o f Mu irhead and Taylo r is be tte r inpractice than aserie s o f co nden se rs

,as it . is the o re tically perfe ct

w hateve r co n n e ctio n s are used fo r Signalling.

W e may n o te that equatio n (9) do e s n o t in vo lve the length o f theh.

l

has be e n n eglected. Had the n e xt te rm o f the se rie s be e n re tain edit w o uld have be e n (w ithin the bracke t),

cable at all,because it is an approximatio n in w hich the fractio n

n—l

4 70 2

4 V 7t2 n2a2l2

_a

24 m 42./t 2 7 ./dc

Whe n t is o n ly afe w multiple s o fa it w ill be asmall fractio no f al", and therefo re the value o f this term w ill be small . It

follo w s, that in w o rking alo ng cable o n the duplex m e tho d averyclo se imitatio n o f the e n te ring curre n t can be obtain ed w ith anartificial cable o f co n siderably sho rte r le n gth than the actual cableto be imitated.

[V e rbatim copy of Profe sso r (Erste d’s o riginal commun icatio n o n his disco very o f

Electro -Magne tismfl

EXPER IMENTA CIRCA EFFECTUM GONELIOTUSELECTR IOI IN AOUM MAGNETICAM.

Prima expe rime n ta circa rem , quam illustrare aggredlo r, 111

scholis de Ele ctricitate , Galvan ismo e t Magn e ti smo proxIme-supe

r io ri hieme ame habitis in stituta sun t. His expe rIme n trs mo n

strari videbatur , ucum magn eticam ope apparatus galvan ici e situ


mo veri ; idque circulo galvan ico cluso,n o n aperto , ut frustra

te n taverun t aliquo t abhin c ann is physici quidam ce le be rrimi .Cum autem hac experime n taapparatu m in us efficaci in stitutae sse n t, ide o que phan ome naeditapro re i gravitate n o n satis lucule n tavidere n tur

,so cium adscivi amicum Esmarch, regiaco n siliis

justicia, ut expe rimen tacum magn o apparatu galvan ico , an obisco njun ctim instructo repe te re n tur e t augeren tur. Etiam vir

egregias Wleugel, eque s auratus o rd. Dan . e t apud n o s prafe ctus

re i gube rnato ria, experime n tis in te rfu it, n obis so cius e t te stis .

Praterea te ste s fue run t ho rum experimen torum vir excelle n tissi

mus e t arege summis ho n o ribus de co ratus Hauch, cujus in rebusnaturalibus scie n tiajam diu in claruit

, vir acutissimus Re in hardt,Histo rianaturalis Pro fe ssor

,v1r In expe rimen tis in stitue ndis saga

cissimus Jacobson , Me dicina Pro fe ssor,e t Chemicus expe rie ntis

simus Ze ise , Philo sophia Do cto r . Sapins equidem so lus exPeri

men tacircamatariam propo situm institui, quaautem itamihi con

tigit de tegere phan omena, in co n ven tu horum viro rum do ctrissi

mo rum repetivi.

In experimentis rece n sendis omn iaprate ribo , qua ad ratio n emre i inve n ie ndam quidem co nduxe run t

,hac autem in ve n ta rem

M plius illustrare n eque un t ; in e is igitur, quare i ratio n em pe rspi

cue demo n stran t, acquie scamus .

Apparatus galvan icus, quo usis summus,

*co n stat vigin ti receptaculis cupre is re

'

ctangularibus, quorum e t lo ngitude e t altitudo

duodecim aqualiter e st pollicum ,latitudo autem duo s pollice s et

dimidium vix excedit. Qvodvis receptaculum duabus luminiscupre is in structum e st ita in clinatis

,ut baculum cupreum , qui

laminam zinceam in aquare ceptaculi proximi suste n tat, po rtare

po ssin t. Aquareceptaculo rum 315 sui po nderis acidi sulphurici et

parite r 316 acidi n itrici co n tin e t. Pars cujusque lamina Z in cea in

aquasubme rsaQvadratum e st,cujus latus circiter lo ngitudin em 10

pollicum habe t. Etiam apparatus . min ore s adhibe ri po ssun t, si

modo filum me tallicum can de face re valean t.

Co njungan tur te rmin i oppo siti apparatus galvan ici pe r filum

me tallicum ,quod brevitatis causain po sterum co nducto rem co njun

gen tem veletiam filum co njungen s appellabimus. Efi'

ectui autem

Sic. Lego usi sumus.


vatum fuisse , mo n ere hand o pus e st. Efl'

ectus igitur, qui lo cumhabe n t in co nflictu e le ctrico

,ab effectibus un ius velalterius vis

e le ctricaquam maxime sun t dive rsi.Si filum co njunge n s in plan e ho rizo ntali sub acu magn etica

po n itur, omn e s e ffe ctus idem sun t ac in plan e super acum tan

tummodo in directio n e inversa. Acus enim magn eticapo lus, subquo ea e st fili conjunge n tis pars, qua electricitatem proxime a

te rmin o n egativo apparatus galvan ici aocipit, o rientem versus

de clinabit.

Ut facilin e hac memo ria re tin ean tur, hac formulautamur

Po lus super quem in trat electricitas n egative ad occide n tem, infra

quam ad o rien tem vertitur.

Si filum co njunge ns in plan e ho rizo ntali itavertitur, ut cum

me ridian o magn e tico angulum se n sim sen simque cre sce n te m fo rmet,

de clinatio acus magn e ticaauge tur, si mo tus fili te ndit versus lo cumacus de turbata; sed minuitur, si filum ab ho e lo co discedit.Filum co njungen s in plan e ho rizo n tali, in quo mo ve tur acus

magn e tica, ope sacomatis aquilibrata, situm , et acui parallelum,candem n ec o rien tem n e c o cciden tem versus de turbat, sed tan tammodo in plan e in clinatio n is un tare facit, itaut po lus, pe n e s quemingreditur in filum v is n egative e le ctricadeprimatur, quan do adlatus o ccide n tale , e t ele ve tur, quando ad o rie n tale situm e st.

Si filum co njunge n s pe rpe ndiculare ad planum meridian i magme tici , v elsupravelin fraacum po n itur, hac in quie te pe rman et ;

excepto si filum sit po lo admodum propin quum : tum e n im e levatur po lus, quando in tro itus fit aparte o cciden tali fili

, e t depri

mitur quan do ab o rien tali fit.

Quando filum co njungen s prepe ndiculare po n itur e regio n e poloacus magn e tica, e t extremitas supe rio r fili ele ctricitatem ate rminon egativo apparatus galvan ici accipit, po lus o rie n tem versus movetur ; po sito autem filo e regio n e puncto in te r polum e t mediumacus sito

,o cciden tem versus agitur. Quan do extrem itas fili

supe rio r electricitatem aterm in o po sitive accipit phan ome nain

ve rsao ccurren t.Si filum co njungen s itaflectitur, ut ad ambas flexuraparte s sibi

fiat parallelum ,aut duo fo rme t cruraparalle la, pole s magn e ticos

pro diversis re i co ndition ibus repellit aut attrahit. Po natur filum

(ERSTED ’S DISCOVERY OF ELECTROM AGNETISM. 463

sit ad me ridian um magn e ticam pe rpe ndiculare e t 00a crus

o rie n tale cum te rmin o n egativo , occiden tale cum po sitive apparatus galvanici quibus itainstructis, po lus proximas repelle tur , vel

ad orien tem velad o ccidentem pro situ plan i crurum. Co njun oto

(sure orie n tali cum te rmin o po sitive e t o ccide n tali cum te rmino

negativo , po lus pro ximas attrahitur. a do planum erurum

po n itur perpendiculare ad locum in ter polem et medium acus,

Acus ex erichaleo , ad instar acus magn etica suspen sa, efi'

e otu

hli conjunge ntis n on mo vetur. Etiam acus ex vitro,velex sic

dicto gummi lace s , s'

un ili experimen to subjectain quiete man e n t.Ex his omn ibus mome n taquadam ad ratio n em ho rum phan o

men o rum reddendam afferro liceat.

Co nflictus electrieus n o n nisi in particulas magn eticas mate riaagere valet. V iden tur omn iaco rpo ra n o n -magn e ticape r conflic

tum ele ctricum pe n etrabiliae sse ; magn e ticave ro , aut po tius particulase rum magn e ticatransite i hujus co nflictus resiste rs, quo fit,

at impetu virium certan tium mo veri po ssin t.

Con flictum electricum in co nducto re n o n includi , sed, ut jam

diximus , simul in spatio circumjacen te idque satis late dispergi , exo bservatio n ibus jam propo sitis satis pate t.

S imiliter ex obse rvatis collige re lice t, hunc co nflictum gyro s

peragere , nam hac e sse vide tur con ditio , sin e quafieri n equeat, ut

eadem pars fili co njungen tis, qua infrapolum magne ticam pofi ta

cum o rien tem ve rsus ferat, suprapo sits eundem o ccide n tem ve rsusagat ; hac en im gyri e st natura

,ut mo tus in partibus o ppo sitis

mo tu progre ssive , juxta lo ngitudin em co nducto ris, co njun ctus,cochleam vellin eam Spiralem fo rmare debe re vide tur , quod tamen ,n isi fallo r,adphan omenahn cusque observataexplicandan ihilco nfe rt.Omn e s in polum se pten trio nalem effectus, hie expo siti, facile

lin eam spiralem dextrorsum flexam percurre re , e t polum septen

trio nalem propefie re , in me ridio nalemautem min ime age re . Effectue

in polum meridro nalem simil ite r eXplicantur, si vi velmate ria


Hujus legis cum naturaco ngrue n tiame lius repe tition e expe rimen

to rum quam longa explicatio n e perspicie tu r. Dijudicatio autem

experime n to rum mu lto fie t facilio r, si cursus virium electricarum

in file co njunge n te sign is pictis velin cisis indicatus fuerit.

Dictis ho c tan tum ad ciam : Demon strasse me in libro septemabhin c an n is edito

, calo rem e t lucem e sse co nflictum electricum.

Ex obse rvatio n ibus nuper adlatis jam ce n cludere lice t, mo tus per

gyro s e tiam in his e ffe ctibus o ccurrere ; quo d ad phan ome na, qua

polaritatem lucis appellan t, illustran daperquam face re puto .

Dabam Hafn iad. 21de Julii 1820 .

Johann is Christianus Orsted .

Eques saratus Ordin is Dan n ebrogici in Universitate HafniensiPro f. Physicss Ord. , Secre tarius Socie tatis Regia

Scien tiarum Hafn iensis.

TYPIS S CHULTZ IANIS .

Tran slation ) .

EXPERIMENTS ON THEEFFECT OFELECTRIC ACTIONON THE MAGNETIC NEEDLE.

The first expe rimen ts o n the subject w hich I un dertake to illustrate w e re se t o n fo o t in the classe s fo r e le ctricity

,galvan ism

,and

magn e tism ,w hich w e re he ld by me in the w in ter just past. By these

expe rime n ts it se em ed to be sho w n that the magn e tic n e edle wasmo ved from its po sitio n by the he lp o fagalvan icapparatus, an d that,w he n the galvan ic circuit w as clo sed, but n o t w he n ope n

, as certainvery ce lebrated physicists in vain attempted several years ago . As,

ho w e ver,the se expe rime n ts w e re co n ducte d w ith some w hat de fective

apparatus, and, o n that acco un t, the phe n ome naw hich w e re pro

duced did n o t se em clear e n o ugh fo r the impo rtan ce o f th e subject,I go t my frie nd Esmarch , the King

’s Min iste r o f Justice

,to join

me,that the expe rime n ts might be repeated an d exte nde d w ith the

great galvan ic apparatus w hich w e fitted up toge the r . A dis

tinguished man , Wleugel, Kn ight o f the Dan ish Order, an d Presiden t o f our Pilo t B oard

,w as also pre se n t at o ur expe rim e n ts asa

partn er and aw itn e ss. B e side s the se the re w e re w itn e sse s at theseexperimen ts that mo st excelle n t man

,de co rated by the King w ith

The Socie ty is indebted fo r this Tran slatio n to the Rev. J . E. Kempe , Rectorof

S t. James’s, Piccadilly, &c. , & c. , to w h om it acco rds its thanks.


If the distan ce o f the jo in ing w ire from the magn e tic n oo dle doesn o t exce ed 2 o f an in ch , the de clination o f the n eedle makes an

angle o fabout If the distan ce is in creased the angle s de creaseas the distan ce s increase . The de clinatio n , ho w ever, var ies acco rding to the efficie n cy o f the apparatus.

The jo in ing w ire can change its place e ither eastw ard o r w est

w ard,pro vided it ke eps apo sitio n paralle l to the n e edle

,w itho ut

any o the r change o f effect than as re spects magn itude ; an d thusthe e ffe ct can by n o mean s be attribute d to attractio n , for the same

po le o f the magn e tic n e edle w hich approache s the jo in in g w irew hile it is place d at the east side o f it o ught to recede from the

same w he n it o ccupie s apo sitio n at the w e st side o f it if thosede clinatio n s depe n de d upo n attractio n s o r repulsio n s.

The jo in ing co n ducto r may co n sist o f se ire ralme tallic w ire s or

bands co n n ected toge ther. The kin d o f me tal do e s n o t alte r thee ffe cts

,except, perhaps, as regards quan tity. We have employed

w ith equal succe ss w ire s o f platinum,go ld, silve r

,co ppe r

,iron,

bands o f lead and tin,amass o f mercury. A co n ducto r is not

w ho lly w ithout effe ct w he n w ate r in terrupts, un le ss the in te rrup°tio n embrace s aspace o f seve ral in che s in length .

The effects o f the jo in ing w ire o n the magn e tic n e e dle passthro ugh glass

,m e tal , w o od

,w ater

,re sin , earthe n w are , sto n e s ; for

ifaplate o f glass, me tal, 0 1°

w o o d be in terpo sed, they are by nomean s de stroyed, n o r do they disappear if plate s o f glass

,metal,

an d w o o d be simultan e o usly in terpo sed inde ed, they se em to be

scarce ly le sse n ed . The re su lt is the same if there is in te rpo sedadisc o fambe r

,aplate o f po rphyry

,an earthen w are ve sse l

,even if

filled w ith w ate r. Our experime n ts have also sho w n that the effectsalready me n tio n ed are n o t changed if the magn e tic n e e dle is shutup in acopper box fille d w ith w ater. It is un n e ce ssary to state

that the passing o f the effe cts thro p gh allthe se mate rials in e lectricity and galvan ism has n eve r be fo re be en obse rved . The e ffects,

the re fore , w hich take place in e le ctric co nflict are as diffe re nt aspo ssible from the e ffects o f o n e e le ctric fo rce 0 1° an o the r.

If the jo in ing w ire is place d in aho rizo n tal plan e un der themagn e tic n e edle , allthe e ffects are the same as in the plan e overthe n e edle

,o n ly in an in ve rse directio n

,for the po le of the

magn e tic n e edle under w hich is that part o f the jo in ing Wire

(ERSTED’S DISCOVERY OF ELECTRO-MAGNETISM . 467

w hich re ce ive s e le ctricity mo st immediate ly from the n egativee nd o f the galvan ic apparatus w ill de clin e to w ards the east.

That the se things may be mo re easily remembere d le t us use

this fo rmula: the po le o ver w hich n egative e lectricity e n ters is

turn ed to w ards the w e st, that under w hich it e n ters to w ards theeast.

If the jo in ing w ire is so turn ed in aho rizo n tal plan e as to fo rmw ith the magn e tic meridian a gradually in creasing angle , thedeclinatio n of the magn e tic n e edle is in creased if the mo tio n o f the

w ire te nds to w ards the place o f the disturbed n e edle , but is le ssen edif the w ire go e s aw ay from this place .

The jo in ing w ire placed in the ho rizo n tal plan e in w hich the magnetic n e edle mo ve s balan ced by mean s o faco un terpo ise

,and paralle l

to the n e edle,disturbs the same n e ithe r eastw ard n or w e stw ard but

on ly make s it quiver in the plan e o f in clinatio n,so that the po le

n ear w hich the n egative e lectric fo rce en te rs the w ire is depre sse dw h e n it is situated at the w e st side and e levated w hen at the east.

If the jo in ing w ire is placed pe rpendicular to the plan e o f the

magn e tic meridian , e ithe r above o r be lo w the n e edle , the latterremain s at re st, un le ss the w ire is ve ry n ear to the po le , fo r thenth e pole is e levate d w hen the e n tran ce is made from the w e ste rn

part o f the w ire and depre ssed w he n it is made from the easte rn .

W hen the jo in ing w ire is placed perpe ndicular to the po le o f the

magn e tic n e edle , an d the uppe r e nd o f'

the w ire re ce ive s e lectricityfrom the n egative e nd o f the galvan ic apparatus, the po le is move dt o w ards the east ; but w he n the w ire is placed oppo site to apo in ts ituated be tw e en the po le an d the middle o f the n e edle it is drivent o w ards the w e st. Whe n the upper e nd o f the w ire rece ive se le ctricity from the po sitive e nd reve rse phen omenaw ill o ccur.

If the jo in ing w ire is so ben t that it is made parallelto itse lf atb o th parts of the be nd

,o r fo rms tw o paralle l legs, it repe ls o r

attracts the magn e tic po le s according to the diffe re n t co nditio n s o f'

t h e case . Let the w ire be placed oppo site to e ither po le o f the

n e e dle so that the plan e of the paralle l legs is pe rpe ndicular to themagn e tic meridian , and let the easte rn leg be jo in ed w ith the n egat ive e nd of the galvan ic apparatus, the w e ste rn w ith the po sitive ,an d w he n this is so arranged the n eare st po le w ill be repelled


e ither eastward or w e stward according to the po sitio n o f the planeo f the legs. Whe n the eastern leg is jo in ed with the po sitive end,

an d the w e stern w ith the n egative , the n eare st po le is attracted.

Whe n the plan e o f'

the legs is placed perpe n dicular to a spotbe tw e e n the po le and the m iddle o f the n eedle the same e ffects

o ccur,o n ly inverted.

A n e e dle o f coppe r, suspen ded like amagn e tic n e edle , is n ot

moved by the effect o f'

ajo in ing w ire . Also n e edle s o f glass, o r ofse -called gum-lac

,subje cte d to the like expe rimen ts, remain at rest.

From allthis it may be allo w able to adduce some co n side rationsin explanatio n o f

'

the se phe n omena.

Ele ctric co nflict can o n ly act upo n magn e tic particle s o f matter.

Alln o n -magn e tic bo die s se em to be pe n e trable thro ugh e lectricco n flict ; but magn etic bodies, o r rather the ir magn e tic particles,se em to re sist the passage o f this co nflict, w hen ce it is that theycan be moved by the impulse o f con te nding fo rce s.That e le ctric conflict is n o t in clo sed in the conducto r, but as w e

have already said is at the same time dispersed in the surro un dingspace , and that somew hat w ide ly is clear e n ough from the e hser

vatio n s already se t fo rth .

In like man n er it is allo w able to gathe r from w hat has be enobse rved that this co nflict pe rforms gyratio n s, fo r this se ems to be a

co nditio n w itho ut w hich it is impo ssible that the same part o f the

jo in ing w ire , w hich, w hen placed be n eath the magn e tic po le , carriesit eastw ard , drive s it w e stw ard w hen placed above ; fo r this is thenature o fagyratio n , that mo tio n s in oppo site parts have an oppo sitedire ctio n . Mo re o ve r, mo tio n by circu its combin ed w ith progre ssivemo tio n

,acco rding to the le ngth o f the co n ducto r, se ems bo un d to

fo rm aco chleao r spiral lin e , w hich, ho w eve r, if'

I am n o t m istaken ,co n tribute s n o thing to the explanatio n o f phen omena hithe rtoobse rved .

Allthe effe cts o n the n o rthern po le , he re se t fo rth, are easily

understo od by stating that n egative ly e lectric fo rce o r matter ru ns

through aspiral lin e be nding to the right, and prope ls the n o rthernpo le

,but do e s n o t act at allupo n the southe rn . The effe cts o n the

so uthern po le are similarly explain ed if w e attribute to fo rce or

matte r po sitive ly e lectrifiedaco n trarymo tio n and the pow er o facting


ing to pay atribute to the memo ry o f the ce lebrated philo sopher.To the membe rs of the So cie ty o f Te legraph Engin e ers the ce lebratio n in memo ry o f this emin e n t man must pro ve peculiarly in te resting, as he , by the discovery o f e le ctro -magn e tism

,laid the founda

tio n o f the ele ctric te legraph . It is thought,there fo re

,that a

sho rt ske tch o f his life w ill n o t prove un w e lcome .

H. C . (Erste d w as bo rn in the to w n o f Rudkjobing,o n the island

o f Lange lan d, at the Great Be lt, on the 1lth o fAugust,1777 . He

and his yo unger bro the r, the sin ce famo us jurist an d state sman ,

Ande rs San doe (Ersted, rece ived in the ir childho od arather iadiffe re n t e ducatio n , but by the ir eage rn e ss and thirst fo r kn owledge ,as w e ll as from the ir remarkable natural gifts

,they w e re so far

succe ssful that they,after asho rt time o f in structio n in Co pe n hagen ,

e spe cially in the classical language s, co uld already, in 1794 , submit

themse lve s to the academical exam inatio n and be accepte d at theun iversity . The fo llo w ing year H. C. (Erste d passe d the philosophical examinatio n

,and in 1797 the pharmaceutical in abrilliant

man n e r. A stro ng love and se n se fo r the study o f natural sciencew as early aw ake n ed in him , the first impulse to w hich w as perhaps

give n w he n as aboy o f thirte e n years o f age he w as appre n ticedto his fathe r

,w ho w as an apo thecary but

,be side s natu ral scie nce ,

he o ccupied himse lf w ith great in te re st w ith aesthe tics an d philosophy. In 1796 he w o n an academical prize fo r an aesthe tic treatise ,an d in 1798 fo r amedical o n e . In 1799 he w as create d Do cto r of

Philoso phy , afte r having de fe n ded his Disse rtatis de fo rmame ta

physice s eleme n taris natures e xte rnae . Whilst abroad (Ersted

published at B e rlin his first great w o rk,w hich afte rw ards appeared

in Fre n ch unde r the title o f R echerche s sur l’ide n tité de s fo rcesele ctrique s e t ehemique s.

”In this w o rk is to be foun d the fo un

datio n o f the e le ctro -chemical system ,w hich the famo us Sw edish

chemist B e rzelius afte rw ards more fully deve loped. (Ersted w as

at that time, and pe rhaps n o t e n tire ly w itho ut justice , lo oke d upo n

by many mo re as anatural philo sophe r than as o n e de vo ted to thestudy o f natural scie n ce ; but late r, it clearly appears from his

w o rks that he mo re and m o re o ccupied himse lf w ith trying exp

me n ts,w hich so on led him to the highe st ren o w n and se cured for

MEMOIR OF PROFESSOR (ERSTEI) . 471

his name apromin ent place in the histo ry o f science . In 18 18 he

began to make in ve stigation s o n the compre ssio n o f w ater, an d

co n structed fo r this purpo se an apparatus w hich is n o w to be fo un din allphysical co llectio n s, and is as remarkable fo r its e legan ce asits corre ctn e ss. In the same year he improved the galvan ic troughapparatus, making many in tere sting expe rimen ts by its mean s

,the

mo st n o ticeable ofw hich, pe rhaps, w as his employme n t o f it fo r the

explo sio n o f min e s by heating aw ire placed in gunpo w der ; but itw as n o t un tiltw o years late r that he realised the ideaw hich earlyo ccupied , and in fact filled his mind , viz .

,that o f finding the true

co n n e ctio n betw e en e le ctricity and magn e tism,by the actio n o f the

galvan ic curren t o n the magn e tic n e edle . In July,1820, his

labo urs in this directio n w e re brought to aco n clusio n,and on the

2lst o f July,1820

,he published his disco very in his treatise

,

Expe rime n tacirca effe ctum co nflictus ele ctrici in acum magn e ticam ,

”w hich w as sen t to allo f the mo st re n ow n ed natural

philo sophers and scie n tific so cie ties;From this momen t his great w o rth as anatural scien tist was

un iversally ackn o w ledged, and ho n o urs poured thick upo n him

from allquarte rs. He became membe r an d ho n o rary membe r o fa

multitude o f learn ed so cie tie s. In 1823 he w as created Membero f the Ro yal So cie ty and Ho n o rary Member o f the R oyal In stitutio n o f Great Britain

,and C o rre spo nding Member o f l’In stitut de

Fran ce (1872 Asso cié étrange r).What immen se influen ce (Ersted’

s discovery exe rcised,and ho w

it w as further deve loped, partly in athe o re tical dire ctio n an d

partly in apractical dire ctio n , n e ed n o t he re be refe rred to ; itw ill in this and o the r re spe cts be snflie ie n t to observe that the to talo fallhis treatise s an d publicatio n s reached the fair n umbe r o f 2 18

,

embracing the w ho le fie ld o f natural scien ce .

The last w o rk published by (Erste d,and n o doubt the mo st

impo rtan t, as an expressio n o f that view o f the w orld w hich hee n te rtain ed from his earlie st time , and in w hich he by degre e s be came

o n ly more co nfirme d,w as his w o rk

,

“the Sou l o f Nature . Fo r

him Nature w as aman ife statio n o f the De ity’s combin ed w isdom

an d creative pow er. The law s o f Nature are reaso n ’s law s. The


true and the beautiful are but differe n t view s of w hat is ratio nal,

and the'

w ho le existen ce fo rms an all-comprehen sive ratio nalw ho leo fDivin e o rigin .

Particular ly for his o w n coun try did (Erste d w o rk in aben eficialman n er

,n o t o nly as ateacher at the Un iversity, w here his w arm

and an imated le ctures e n raptured his audien ce , and w o n manyvo tarie s for the study ofNature , but his in tere st w as as many-sidedas his learn ing, and in many in stan ce s have his le cture s and w ritings give n in structio n and guidance to his fe llo w -citize ns . He

w o rked e n erge tically fo r the purpo se o f making the scie n ce of

Nature mo re acce ssible to the public at large , as w e ll as that theinflue n ce o f

"

scie nce o n daily life should be deve loped in his o w n

coun try in apractical directio n . It w as w ith this idea that hefoun ded the So cie ty for Advan cemen t o fNatural Scie nce , and thathe succe ede d in 1829 in establishing the Po lyte chn ic In stitutio n atCope nhage n

,fo r w hich he , as dire ctor and teacher, w o rked w ith

un tiring e n ergy up to his deathOn the 7th o f November, 1850, he had be e n teache r at theUn iversity fo r fifty years

,andalarge numbe r o f his frien ds

,pupils,

and hearers prepared afe stival fo r him o n that day . Ho n ouredby his King

,loved and re spected by allw ho had expe rie n ce d the

go od fo rtun e o f coming in co n tact w ith him,(Ersted lo o ked upon

that day as the happie st in his life . A few mon ths late r, o n the

9th o f March, 185 1, afte r an apparen tly light illn e ss, he passedquie tly aw ay, de eply mourn ed by all. Emin en t as a scho lar,equally great w as he as aman , modest and len ie n t in his judgmen t o f o thers, strict w ith regard to himse lf

,be n e vo le n t

,alw ays

ready to he lp o thers w ith advice and de ed ; himse lf truthful in thehighe st degre e , he deman ded truthfuln ess from o the rs as the irfirst duty .

(Ersted visited Englan d seve ral time s, and he w as o n afi' ie ndlyfo o ting w ith mo st o f its re n o w n ed scie n tific men . In 1823 he made

the acquain tan ce o f Davy,lVollasto n

,and o thers in 1846 he to ok

part in the me e ting o f Natural Philo sophe rs at So uthampto n,and

o n that o ccasio n he w as particularly distinguished. Amo n gst o thersSir John Hersche l spoke at the co n cluding me eting in the most


earth may be applied w itho ut affecting the defle ction o f the

galvan ome ter n e edle G ; w he n P is thus found the re sistan ce sA B E and B w ill be propo rtional, that is

A E

s n

T he applicatio n o f earth at the po in t P, w hile leaving the gal

van ome te r undisturbed , must co n side rably mo dify the curre n t se t

up in R by the e le ctromo tive E, and he re w e have the first step

to w ards aduplex te legraph .

Apparatus w as arranged as in fig. 2. A B,AI B1 , an d R w e re

re sistan ce co ils o f o n e fo rm o r an o the r,G G1 w ere polarise d re lays,

and w e re so co n n ecte d up that w he n the curren t flo w e d thro ughthem the to ngue o f G w as attracte d to the co n tact sto p

,w hile that

o f GI w as repe lled. In the circu it o f each re lay the re w as afairlyse n sitive galvan o scope n o t sho w n in the figure . K K

l w e re o rdinary Mo rse keys, E w as abatte ry o f 30 ce lls o f small in te rnalre sistan ce , and L w as the artificial lin e o f abo ut 3000 ohms. The

lo cal circu its differe d in n o w ay from tho se fo r o rdinary singlew o rking

,and

,fo r the sake o f clearn e ss

,are omitte d from the

figure .

Fair w o rkable re sults w ere obtain ed w he n A B w as equal tothe re sistance o f the batte ry E added to that o f the lin e an d o f the

distan t statio n ’

s apparatus, AI B1 2 G1 , an d R equal to the

lin e an d the home statio n ’

s apparatus. The re sistan ce o f the re laycircuits w as abo ut 800 ohms.

The adjustme n t w as e ffected in the fo llo w ing man n e r. The

to ngue o f G w as made to re st w e ll again st the in sulate d o r agate

sto p,so that the curre n t passing thro ugh the system sho u ld be

unable to draw it o ve r to the co n tact stop . The to ngue o f G,on

the o the r hand, w as so placed as to re st again st the co n tact stop

w he n n o curre n t w as passing, an d to be pushe dagain st the in su latedsto p by the curre n t from E. The w ire s from K K

1 , be ing fitted

w ith trave lling pegs, w e re the n mo ved alo ng A B and AIB1un til

apo in t w as fo un d in each at w hich making and breakin g co n tact

w ith earth by mean s o fthe levers had n o effe ct o n the defle ctio n s ofthe ir co rre spo n ding galvan o scope s, that is to say, w orkin g K had


Thus w e had w hen K1w as at re st,

and w hen K1 w as depre ssed,2A

:

E A Eas be fo re

B L + Y + R B L +Y + E

2

This compe n satio n w as n o t required w hen K w as depre ssed,because the de crease in the re sistan ce of the home apparatus causedthe reby w as so small compared to the to tal resistan ce that the

%1 ITTET E' w as practically co rrect fo r this po sitio n of

1

the lever.

Subsequen t experime nts show ed that the re sistan ce R could becon ve n ie n tly replaced by ase co nd batte ry E, fig. 4

, and the

automatic arrangemen t dispen sed w ith. This battery w as e qual,approximate ly, in in te rnal re sistan ce and e lectromo tive fo rce to E,and w as co nn ected up in the o ppo site w ay as sho w n in the figure .

A B and AI B1 w ere made equal, and w e re each abo u t o n e

e ighth o f the re sistan ce o f the batte ry (E o r E1 ), plus that o f the

lin e and o f the o ther statio n ’

sapparatus. The adjustmen t w as e ffe ctedas in fig. 2

,except that the to ngue o fG w as also made to re st against

the co n tact stop w he n n o curre nt w as passing. This arrangemen tw orked w e ll o n bo th artificial and actual lin e s, and is superio r tothe first.

Its actio n is as fo llow s : Fo r the sake o f illustratio n le t A B

G 620 ohms, AI B1 G

1620

,E E

1100

,and L

2590 . Whe n the keys are at re st acurre n t circulates in the

system ,the strength o f w hich is the added e ffe ct o f Eand E

, ,— viz.

34 10’

1 1 the sum o f the e le ctromo tive fo rce s. Of this o nly o n e -halfl

3410

to ke ep them w e ll ope n . Le t K be held do w n , calculatio n andobse rvation alike show that the curren t in G is n o taffe cte d thereby ;

3410 be ing the sum o fallthe re sistan ce in the circuit, and

go e s thro ugh the re lays,and

,as w e have se e n

, just suffice s

ON DUPLEX TELEGRAPHY. 477

E1 still sends a curren t to lin e , w hich 18 practically the same as

1the slight m

crease,w hich w e n e ed n o t stop to appre ciate

,be ing due to the to tal

re sistan ce in circu it be ing n o w le ss than befo re the depre ssio n of

K . But the greater part o f the curren t from E n o w go e s to earth

maAan d K and G B and K, and o nly

40320 go e s to lin e , o r o n e

be fo re , though in reality alittle stro nger

tw e lfth o f its o riginal strength. The curren t in the lin e is there fo re

40320 o r31

1

48 ’ and sin ce but o n e-half o f this traverse s G1

62

1

96in stead o f

34

1

10repre sen ts the curren t by w hich the distan t

re lay is actuated,and this by reaso n o f the adjustmen t is in sufficie n tto ke ep the to n gue from falling o ver to the con tact stop asignalis therefo re reco rded. The same reaso n ing applie s w he n Kl is helddo w n , G1 is unaffe cted, w hile the curre n t in G is reduced to n earlyo n e -half

,an d pe rmits the to ngue to fall o ver to the co n tact stop ,

an d reco rd asignal. When bo th keys are dow n at the same timethe re lays rece ive acurre n t w hich is almo st the same as w hen they

are w o rked singly, w hile acurren t o f o n ly 20460 go e s to the lin e .

Acco rding, there fore , to the po sitio n s o f the lovers the lin e is1

traversed by curren ts of the fo llow ing strengths1705

w hen bo th

leve rs are at rest, 311

48w hen o n e upand o n e do w n ,and 20460 w he n

bo th do w n . On e advan tage o f this arrangeme n t is that as it dispe n se s w ith the artificial lin e required by o the r systems it alsodispe n ses w ith the use o f co n den sers.

The system has be en in successful o peration o n the Shiraz-Teheranlin e , Persia, 600 miles long, No . 5 w ire . Any tw o statio n s po sse sse d o f arhe o stat can easily jo in up duplex w ith the o rdinaryapparatus, and if they po sse ss slide s so much the better.


ON THE CONSTRUCTION OF CABLE-KEYS.

It very se ldom happen s that in strumen t-make rs turn o ut acablekey ready to me e t the practical requiremen ts o f ope rators. No

do ubt this arise s from the w an t o f kn o w ing w hat is really requ ired.

The mo st beautiful w o rkman ship is o fte n spo ilt by some,e rro r in

the arrangeme n t o f the parts o f the key, and I w illhe re en deavourto po in t o ut the e rro rs w hich are usually made in the co n structiono f keys fo r cable-w orking, and the remedies w hich can be appliedin future .

Diffe ren t pe ople have differe n t Opin io n s, and do ubtle ss there w illbe some w ho w ill differ from me e ve n in the co n structio n o fakey,but I think I may claim as great an experie n ce in the matter ofcable -keys and cable-operato rs as any o n e , and the remarks I amabo ut to make are the re sult o f upw ards o f ten years’

care fu l e hservatio n o f pe rso n s andapparatus ; and although there may be excep

tio n s to every rule the fo llo w ing is the average re sult o f my exporicuce .

The e rro rs in co n st ructio n areI . The springs in the o rdinary fo rm o f cable -key are to o stiff

and requ ire an amo un t o f pre ssure to in sure go o d co n tacts, w hichso o n tire s an ope rato r

’s finge rs,and cause s him to se n d irregularly

,

mud in asho rt time to co n side rably reduce his spe ed o f se n ding .

I have n o w be fo re me an e w key , and it w ill pe rhaps be scarce lycredited w he n I state that to bring the “do t key do w n to the

unde r co n tact require s aw e ight o f 15 oun ce s, an d to bring do w nthe “dash key it require s 17 o un ce s. No w imagin e an o pe rato rw o rking at the rate o f o n ly tw e lve w o rds am in ute

,five le tte rs pe r

w o rd, an d thre e signals pe r le tte r, fo r o n e hour,w ith his finge rs

o n ly,each signal be ing pro duced by afinger-pre ssure o f o n e po und

w e ight,plus alittle fo r firm co n tact

, and the re sult surprise s you,fo r 12 x 5 x 3 x 60 lbs. pe r ho ur ; multiply this by e ightho urs fo r aday’

s w o rk,and it w ill be se e n w hat an e n o rmo us

amo un t o f muscu lar po w er is exe rted, in the aggregate , in aday’

s

duty at the “light o ccupatio n o f cable w o rk . It w o uld be ve rylittle sho rt o f crue lty to an imals to fo rce aman to w o rk such akey for aw ho le duty, se tting aside the fact that such akey mu st


this arrangeme n t during an e ight hours’spe ll o f se n ding , as com

pared w ith an equalspe ll of w o rking w ith akey of the o rdinaryco n structio n , can o n ly be e stimate d by tho se w ho have to man ipalate it.

IV . The shape o f the tappe rs is, as arule , w ro ng the edge sareto o thin and sharp,and they by n o mean s find favour w ith o perators;the uppe r surface s are , mo re ove r, to o co n cave . The tappe rs shouldbe made but ve ry slightly co n cave o n the top ; the e dge s should bemade thicke r, and ro unded o r beve lled o ff, and the diame ter foundto be mo st co nven ie n t is that o fabro n ze halfpen ny.

It may be tho ught by some pe rso n s that the keys m ight haveco nvex kn o bs like the lan d-lin e keys ; but this w ould n o t do . In

the Morse key there is but o n e leve r w o rked by o n e han d , and thekn o b is usually grasped in the han d, o r in clo sed by the fingers,w he reas in the cable -keys there are tw o leve rs

,o r springs

,w orked

o f n e ce ssity by the fingers o f o n e hand,and slightly co n cave tappers

are fo und mo st co n ve n ien t fo r the finge rs in sen ding. Upo n aconvex surface the re w o uld alw ays be aliability o f the finge rs to slipo ff in sen ding, and o perato rs there fore pre fer the slightly con cavetappe rs w ith an 8 o z. spring.

It must be bo rn e in m ind that the han d is n o t shifte d from keyto key in se nding

,but the w rist is statio nary, re sting upo n the table

o r upo n araised blo ck a little abo ve the leve l o f the table,and

freque n tly upo n ame ssage -pad, so as to give mo re fre edom to the

finge rs. Whe n the springs are to o stro ng (such as the 1 lb . springsabove re fe rred to ),and in ve ry quick se nding, the w rist can n o t be atre st

, and the n it is raised , bringing the assistance o f the arm in toplay to provide fo r the extrapo w er required

,the fingersalo n e be ing

in sufficie n t fo r the purpo se .

V. The distan ce from the cen tre o f o n e tappe r to the ce n tre of

the o the r sho uld be abo ut o n e in ch and thre e -quarte rs.

By in tro ducing the se little improveme n ts in the co n structio n of

the o rdinary cable -keys,

” Me ssrs. Smith, Jo n e s, Bro w n andR obin so n w ill co n fer some comfo rt upo n cable o pe rato rs

, an d re

ce ive the ir go o d w ishe s in re turn .

JAS . GRAVES .

Valen tia, November 9, 1876.

QUADRANT ELECTROMETER WITH BIFILAR SUSPENSION . 481

QUADRANT ELECTROMETER WITH BIFILARSUSPENSION .

“

During the last n in e mo n ths w e have be en regularly using aThomso n

’s Quadran t Ele ctrome te r, that arrive d in this coun try a

year ago . In May o f this year w e first o bse rved that w hen aco n stan t differe n ce o f po ten tials w as measured the primary defle ctio n D slo w ly increased to alimit D 8 in about ten m inute s

,8

be ing asmall in crease . Whe n the quadran ts w ere sudden ly co nn ected the zero w as 8 in advance o f its primary po sitio n

, to w hichit o n ly re turn ed after some time . 8 is alw ays o f the same sign asD . This actio n has slo w ly in creased as the w eathe r has become

ho tte r, an d n o w (August) isas much as o n e -fifth if the n e e dle be

kept defle cted fo r about o n e ho ur. When it w as first obse rved, the

in strume n t w as take n to piece sand tho ro ughly clean ed, to avo id thisabn o rmal actio n be ing complicated by shreds causing any lo ssfrom the n e edle to the quadran ts. After charging the Leyden jar,an irregular w ande ring o f the zero w as observed w hen allthequadran ts w ere kept co n n e cted . This may have been due partlyfrom the air abo ut the silk fibre s drying

,and partly from the lo ss

o f charge o f the jar, be ing appare n tly (greatat first) due to soakingin fo r w e had se e n that at any time if the charge in the jar w eresudde n ly altere d the e lectric ze ro altered

,eve n although it pre

v io usly co in cided w ith the mechan icalzero , that is, the zero o f the

in strumen t w hen the quadran ts, the in side and o utside o f the jar,are at the same po ten tial. After this irregular mo tio n o f the ze ro

had to agreat e xten t subsided the previous “yie lding e ffe ct w as

again man ife sted . At first sight it appeared like an in crease o f

differen ce o f po te n tials be tw e e n the quadran ts, due to some e le ctrom o tive fo rce acting through agreat re sistan ce , and as in Jun e w e

o bserved that the in sulating paraffin -w ax o n the ebo n ite o f the

ele ctrodes had slightly me lted, and had spread itse lfas athin laye rove r the uppe r surface o f the quadran ts, w e hoped that w e haddiscovered the cause o f the phen omen o n in this paraffin havingin serted itse lf be tw e e n the fe e t o f the e lectro de s and the quadran ts.

A paper on Unifilar Suspension by the same authors w ill appear in afuturen umber.

VOL. V .


Ho w ever, taking the e le ctrome te r to pie ce s and carefully clean ingthe quadran ts and the e lectrode s produced n o impro veme n t

,anda

direct measuremen t w ith aWheatsto n e ’

s bridge sho w e d the absenceof any re sistan ce be tw een the quadran ts and any o f the ir con

n e ctio n s. Quan titive experime n ts pro ve that for agive n charge

in the jar, and fo r agive n po sitio n of the quadran ts, the deflectioncorre spo nding w ith any fixed differen ce o f po ten tials is con stant,and that the marked steady mo tio n o f the deflecte d n e edle is reallydue to aco rre spo nding mo tion o f the zero .

The phen ome n o n , therefo re , bears the appearan ce o f aviscous

yie lding o r in crease of the silk fibre s under con tinued stre ss still,as w e are n o t aw are of any such yie lding be ing obse rve d in anyo the r quadran t e le ctrome ter, an d as w e have n o t expe rie nced ito urse lve s in any o f the e le ctrometers that w e have use d in England

,

w e put fo rw ard this suggestio n w ith diffidence , and are anxious toe licit the view s o f the Members o f the Socie ty o f Te legraphEngin e ers o n this subject.In bifilar suspe n sio n s adefle ctio n of the n eedle ncreases the

te n sio n o f the fibres, co nsequen tly, if this in crease d te n sio n be

main tain ed fo r atime , there w ill be probably a lengthen in g o f the

fibre s. If,the refo re , the n e edle

.

and fibres w ere pe rfe ctly sym

me trical , the effect o f this w o uld be to slightly low e r the n e edle ,and

,if w e n egle ct fo r amome n t any alte ratio n o f e lectricattraction

produced by this lo w ering o f the n e edle re lative ly to the quadran t,

this lo w e ring w o uld n o t alte r the ze ro po sition . But if the o riginalte n sio n s o f the fibre s are slightly un equal , o r if e ither o f the fibres

te nds to yie ld mo re than the o the r fo r the same stre ss, the n then e edle

,in additio n to be ing lo w ered, w ill remain slightly de flected

afte r the removal o f the defle cting co uple . And n o w,in addition

to this,the lo w ering o f the n e edle may probably, eve n if the yie ld

ing o f the fibre s w ere exactly equal,cause an alteratio n o f the zero ,

from change o f the e le ctric attractio n s produced by the approach ofthe n e edle to the lo w e r half o f the quadran ts due to w an t o f perfectsymme try o f the n e edle an d quadran ts.

The effect o f in equality o f te n sio n w e have verified to a certaine xte n t by adirect experime n t o n asilk bifilar suspen sio n

,in con

n e ctio n w ith w hich there w e re n o e le ctricattractio ns ; co n sequen tly,


ON A NEW MODE OF STUDYING EARTH CURRENTSAND THE VARIATIONS IN TERRESTRIAL

MAGNETISM.

A very small magn et w ith attached m irro r is suspe n ded by asingle fibre o f silk . Exactly unde rn eath this magn e t

,but about

fo ur in che s be lo w it, is suspended by afe w fibres,amuch larger

magn e t, w ith copper dampers applied in the usualw ay .

Things be ing thus arranged, it is eviden t that the small magnetis n early in an astatic state as regards the earth’

s dire ctive force ,w hereas the large magn e t is scarce ly affected. If n e w the dailyvariatio n s o f the suspended magn e t are due to change s in the

directive fo rce o fthe earth as aw ho le , in o ther w o rds chan ge s in thedirection o f the terre strial lin e s o f fo rce , bo th magn e ts w ill beequally affe cte d by such variatio n s, con seque n tly the variatio n s of

the small magn e t w ill be n o greater in co n seque nce o f its astaticco n dition than they w o uld be if the lo w er magn e t w ere removed.

If,o n the co n trary, the daily variatio n s are due , n o t to changes in

the directio n of the te rre strial lin e s o f fo rce , but to the actio n of

lo cal cause s, such as earth curren ts, w e shall have the daily variatio n s large ly magn ified. I had an in strume n t o f the fo rm de scribedabove co n structe d about tw o years ago , and fo r a co n side rabletime had half-ho urly readings take n , simultan e ously , o f the po sitio n o f the smallmagn e t o f the earth curre n ts in a lin e run n ingdue n o rth and south, and o f the po sitio n o famagn e t in amagn etome ter co n structed o n Gauss’s prin ciple . I fo und

,

1st,That the variatio n s o f the small magn e t o f the astatic

magn e tome te r w e re greatly amplified2md, That the variatio n s agre ed e n tire ly n e ither w ith tho se of

the earth curre n ts n o r w ith tho se o f the o rdinary magn e tome ter ;

3rd,They w ere gen erally much mo re regular than the variations

o f the earth curren ts.

Afte r I had be e n some time at w o rk w ith this in strumen t I fo und

that amethod o f observing o f asome w hat similar nature had beenpractised many years ago by Me ssrs. Barlo w and Christie but the

me thod they used diffe red in this importan t po in t from min e : in

NEW MODE OF STUDYING EARTH CURRENTS. 485

the irs the large magn e t w as fixed, w hereas in min e it is fre e ly suspe n ded. When the magn e t is fixed the slighte st change in the

dire ction o f the lin es o f fo rce o f the earth w ill make alargealte ratio n in the po sitio n o f the small magn e t

,just as the slighte st

alteratio n in the po sition o f the large magn e t,re lative ly to the lin e s

o f force o f the earth, w ill cause alarge angular displaceme n t o f thesmallon e . We are n o t able there fore by using afixed magn et

,

Fig. 1.

afte r the me thod o f Barlo w and Christie , to separate the effe ct o flo calactio n s from that o f the variatio n s in the dire ctive fo rce of the

earth ; n eve rthe le ss there is an impo rtan t result to be gatheredfrom the ir obse rvatio n s, w hich may n o t be gen erally kn o w n .

These able observers w ere n o t co n te n t w ith observing the variat io n s o f the astatic n e edle in the po sitio n o f the magn e tic meridian ,but observed them also in an umber o f o ther po sitio n s, the magn e tbe ing defle cted from its n o rth and so uth po sitio n byathird magn e t.They thus fo und that the amplitude o f the variatio n s diffe red indifl

'

eren t azimuths, and they further determin ed that the po sition


in w hich the amplitude w as greate st w as that sho w n in the following diagram ,

w hich is copied from Barlow ’s paper o n Magn etism

in the Encyclope diaMetropo litana.If n e w this diagram be compared w ith the follo w ing, w h ich is

copied from C. V. Walker’s diagram,

sho w ing the directio n of

maximum earth curren ts (Philo sophical Transactio ns for the year1861

, vol. 15 1, part it w ill be se e n that the po sitio n o fmaximum

variatio n o f the astatic n e edle , as determin ed by Barlo w and

Christie, co rre s

po nds very n early w ith the dire ctio n o f maximum

earth curren ts as de te rmin ed by Walker, years late r, and as represe n te d by the lin e R R’

in his figure .


strumen t, and pre ssed upwards again st the co n tacts b y m e al

the spiral springs.To the e nd o f the levers A and B , and fo llo w in g t h e ir u p

do w n moveme n ts, are attached the n e edle s M and S ,o f w h icl

regulate s the marking curren t and S the spacing curr e n t .

The se n e edle s are n o t fixed to any o f the movin g par ts o f

in strume n t, but they are simply fo rced upw ards by th e p re ssu r ethe spiral springs upo n the levers Aand B ,

and the se le v e rs rem :

in co n tact w ith the co n tact-studs so long as the n e e dle s are p :

mitted to move fre e ly up and do w n .

The n e edle s M and S thus de te rmin e w hether th e co n n e ctic

be tw e en battery and lin e shall be direct and w ith fu ll p o w e r o r n o

They rise alternate ly, un til they touch the perfo rate d r ibbo n ; if thn e edle en ters aho le

,the curre n t go e s to earth w ith fu llstre ngth

but if it do e s n o t hit upo n aho le its mo tio n and that o f th e le vel

is sto pped by the paper, and, as the stud o n the ro cking-beam co n

tin n e s to rise,con tact is broke n be tw e e n the stud and the lever,

an d w he n this takes place are sistan ce R is in serted be tw e e n batteryand earth, co n side rably w eaken ing the curre n t and its effect.As the ro cking-beam and the levers o scillate , the disc D is

pushed from o n e side to the.

o ther, and the small ro ller E, w hich is

fixed o n aspring, jerks it o ver after it has be en pushed over thecen tre . Tw o pin s preven t the disc from be ing pushed any furtherto the sides than n e eded. The disc D con sists o f an ebo nite piecew ith asemi-circular me tal pie ce o n each side . On each half isa

me tal stud 1cand ate rminal f, thro ugh w hich co ppe r or zinc is putm co n n e ctio n w ith earth o r lin e . The small ebo n ite piece e pre

ve n ts the leve r Z from coming in to co n tact w ith the leverK, andthus putting the battery o n sho rt circuit.In fig. 1 zin c is in co n n e ctio n w ith lin e and copper w ith earth,

in fig. 3 coppe r is to lin e and zin c to earth .

Whe n the in strumen t is in the po sitio n sho w n in figs. 1and 3,the curren t flo w s through the lever B , the springs F, the frame ofthe in strumen t, and the leve r A,

direct to earth ; but when thein strume n t is in the reverse po sitio n

,w here o n e o f the needleshas

be e n oppo sed in its l‘

lSlllg mo tio n by the paper ribbon,andconseen tly the co n tact be tw e e n the co rre spo nding leverandstudon


strumen t, and pre ssed upwards again st the co n tacts b y m e

the spiral springs.To the e nd o f the levers A and B ,

and fo llo w ing t h e ir 11

do w n moveme n ts, are attached the n e edle s M and S ,o f W h i

regulate s the marking curre n t an d S the spacing curr e n t .

The se n e edles are n o t fixed to any o f the mo vin g par ts 0

in strume n t, but they are simply fo rce d upw ards by th e p re ssthe spiral springs upo n the levers Aand B ,

and the se le v e rs re

in co n tact w ith the co n tact-studs so lo ng as the n e e dle s are


The n e edle s M and S thus determin e w hether th e co n n e c

be tw e en battery and lin e shall be direct and w ith fullp o w e r o r

They rise alte rnate ly, un til they touch the perfo rate d r ibbo n ; ifn e edle e n ters aho le

,the curre n t go e s to earth w ith fu llstre n

but if it do e s n o t hit upo n aho le its mo tio n and that o f the la

is stopped by the paper, and, as the stud o n the ro cking-beam c

tin ue s to rise , co n tact is broke n betw e en the stud and the lev

an d w hen this take s place are sistan ce R is in serted be tw e en batteand earth, con side rably w eaken ing the curren t and its effect.As the ro cking-beam and the leve rs o scillate , the disc Dpushed from o n e side to the

.

o ther, and the small ro ller E, w hich

fixed o n aspring, jerks it o ver after it has been pushed overcen tre . Tw o pin s preven t the disc from be ing pushed any furtlto the sides than n e eded. The disc D co n sists o f an ebonite piw ith asemi-circular me tal pie ce o n each side . On each half isme tal stud 1cand ate rminal f, through w hich coppe r or zinc is putm co n n ectio n w ith earth o r lin e . The smallebo n ite piece e pre

ve n ts the lever Z from coming in to co n tact w ith the leverK,and

thus putting the batte ry o n sho rt circuit.In fig. 1 zin c is in con n ectio n w ith lin e and copper w ith earth,


Whe n the in strume n t is in the po sitio n sho w n in figs. 1and3,the curre n t flo w s thro ugh the lever B , the springs F, the frame ofthe in strumen t, and the leve r A

,direct to earth ; but when the

in strume n t is in the reverse po sitio n,w here o n e o f the needles has

be e n oppo sed in its rlsmg mo tio n by the paper ribbon,andconse

“i en tly the co n tact be tw e e n the co rre spo nding leverandstudon


strumen t, an d pre ssed upwards again st the co n tacts by

the spiral springs.

To the e nd o f the leve rs A and B , and fo llo w ing th e irdo w n moveme n ts, are attached the n e edle s M and S, o f

regulate s the marking curre n t and S the spacing curre n t .

The se n e edle s are n o t fixed to any o f the moving pain strume n t, but they are simply fo rced upw ards by the pmthe spiral springs upo n the levers Aand B , and the se le ve r sin co n tact w ith the co n tact-studs so lo ng as the n e edle s


The n e edle s M and S thus determin e w he ther the co

betw e e n battery and lin e shall be directand w ith full po w e r

They rise alternate ly, un til they to uch the perfo rated ribbo nn e edle en te rs aho le

,the curren t go e s to earth w ith full 8

but if it do e s n o t hit upo n aho le its mo tio n and that o f

is stopped by the pape r, and, as the stud o n the ro cking-betin ue s to rise , co n tact is broken be tw e e n the stud an d thean d w he n this takes place are sistan ce R is in serted be tw e e n

and earth, co n side rably w eaken ing the curren t and its effe ct.As the ro cking-beam and the levers o scillate , the discpushed from o n e side to the o the r

, and the small ro ller E, wfixed o n aspring, jerks it o ver after it has be en pushed o r

cen tre . Tw o pin s preven t the disc from be ing pushed anyto the sides than n e eded. The disc D con sists o f an ebo n itw ith asemi-circular me tal pie ce o n each side . On each hmetalstud lo and ate rminal f, thro ugh w hich co ppe r o r zincm co n n e ctio n w ith earth o r lin e . The small ebo n ite piece eve n ts the lever Z fi'

om coming in to co n tact w ith the leverK,thus putting the batte ry o n sho rt circuit.In fig. 1 zin c is in co n n ectio n w ith lin e and coppe r w ith e


Whe n the in strumen t is in the po sition sho w n in figs. 1

the curren t flo w s thro ugh the lever B , the springs F, the frthe in strume n t, and the leve r A,

direct to earth ; but w henin strumen t is in the reverse po sitio n , w here o n e o f the needlesbe e n oppo sed in its rising mo tio n by the pape r ribbon

,and co

quen tly the co n tact be tw e en the co rre spo nding leve r andstud


strumen t, and pre ssed upwards again st the co n tacts by

the spiral springs.To the end o f the lovers A and B ,

and fo llo w ing th e i rdo w n moveme n ts, are attached the n e edle s M and S , o f

regulate s the marking curre n t and S the spacing curre n t .

The se n e edles are n o t fixed to any o f the moving par

in strume n t,but they are simply fo rced upw ards by th e p

the spiral springs upon the levers Aand B ,and the se le v e r

in co n tact w ith the co n tact-studs so lo ng as the n e edle s

mitted to mo ve fre e ly up and do w n .

The n e edle s M and S thus determin e w he ther the co

be tw e en battery and lin e shall be dire ctand w ith full p o w e r

They rise alte rnate ly, un til they touch the pe rfo rate d ribbo nn e edle en te rs aho le

,the curre n t go e s to earth w ith full 8

but if it do e s n o t hit upo n aho le its mo tio n and that o f

is stopped by the paper, and, as the stud o n the ro cking-be ertin n e s to rise

, co n tact is broke n betw e en the stud and thean d w he n this take s place are sistan ce R is in serted be tw e e nand earth, co n side rably w eaken ing the curren t and its effect

As the ro cking-beam and the levers o scillate , the dipushed from o n e side to the o ther, and the small ro ller E, vfixed o n aspring, jerks it o ver after it has be en pushed o

ce n tre . Tw o pin s preven t the disc from be ing pushed anyto the side s than n e eded. The disc D co n sists of an ebon itw ith asem i-circular me tal pie ce o n each side . On eachme tal stud lo and ate rm inal f, thro ugh w hich coppe r or zincm co n n ectio n w ith earth o r lin e . The small ebo n ite piece ave n ts the leve r Z from coming in to co n tact w ith the leverKthus putting the batte ry o n sho rt circuit.In fig. 1 z in c is in con n e ction w ith lin e and copper w ith

in fig. 3 coppe r is to lin e an d zin c to earth .

Whe n the in strumen t is in the po sitio n sho w n in figs. 1

the curren t flo w s through the lever B , the springs F, the fitthe in strumen t, and the leve r A

,direct to earth ; but w hen

in strume n t is in the reverse po sitio n, whe re o n e o f the needles

be en oppo sed in its rising mo tio n by the paper ribbon,andcom

quen tly the co n tact be tw e e n the co rre spo nding leverandsun“


strume n t, and pre ssed upwards again st the co n tacts by mean s of

the spiral springs.

To the e nd o f the levers A and B ,and fo llo w ing the ir up

-and

do w n mo veme n ts, are attached the n e edle s M and S, o f w h ich Mregulate s the marking curre n t and S the spacing curre n t .

The se n e edles are n o t fixed to any o f the moving parts o f the

in strum e n t, but they are simply fo rced upwards by the pre ssure ofthe spiral springs upo n the love rs Aand B ,

an d the se le vers remainin co n tact w ith the co n tact-studs so lo ng as the n eedle s are per

m itted to mo ve fre e ly up and do w n .

The n e edle s M and S thus dete rmin e w he ther the co n n ectio nbetw e e n battery and lin e shall be direct and w ith full po w e r o r n o t.

They rise alte rnate ly, un til they touch the pe rfo rated ribbo n ; if'

the

n e edle e n ters aho le,the curren t go e s to earth w ith fu ll stre ngth,

but if'

it do es n o t hit upon aho le its mo tio n and that o f the lever

is stoppe d by the paper, and, as the stud o n the rocking-beam con

tin n e s to rise , co n tact is broke n betw e e n the stud an d the lever,an d w he n this take s place are sistan ce R is in serted be tw e e n batteryand earth, co n side rably w eaken ing the curren t and its effe ct .

As the ro cking-beam and the levers o scillate , the disc D is

pushed from o n e side to the o the r,and t he small ro ller E, w hich is

fixed o n aspring, jerks it o ver afte r it has be en pushed o ve r the

cen tre . Tw o pin s preven t the disc from be ing pushed an y furtherto the side s than n e eded. The disc D co n sists o f an ebo n ite piecew ith asem i-circular me tal pie ce o n each side . On each half isame tal stud It and ate rm inal f, thro ugh w hich coppe r o r z in c is putm co n n e ctio n w ith earth o r lin e . The small ebo n ite pie ce e pre

ve n ts the lever Z fi'

om coming in to co n tact w ith the leve r K, and

thus putting the batte ry o n sho rt circuit.In fig. 1 zin c is in co n n e ctio n w ith lin e and coppe r w ith earth,

in fig. 3 co ppe r is to lin e and zin c to earth .

“711ml the in strume n t is in the po sitio n sho w n in figs. 1 and 3,the curre n t flo w s thro ugh the leve r B , the sprin gs F, the fram e of

the in strume n t, and the leve r A,direct to earth ; but w he n the

in strume n t is in the reve rse po sitio n,w he re o n e o f the n e edle s has

be e n o ppo sed in its rising mo tio n by the paper ribbo n,and co use

que n tly the co n tact be tw e e n the co rre spo nding leve r and stud o n


pe rfo rate d ribbo n w ith the le tters A,B, and C ready for trans

missio n .

PERFORATED R IBBON

m amas cusscursoa‘

,

spac mo co n curs (s )

S IGNALS AS R EC G 'VED

Fig. 6.

In fig. 7 is sho w n aperforated ribbo n w ith the le tters A,I, and

T,and if the se le tte rs are se n t the curre n ts w ill flo w as fo llo w sFirst

, the marking-n e edle M passes through the ho le 1 in the

perfo rated ribbo n , putting zinc to lin e and copper to earth, as infig. 1 . This curren t acts upo n the armature o f the re ce ive r in adirectio n to pre ss the w riting disc again st the Mo rse slip

,and the

do t has be e n commen ced . No w the spacing-n e edle S rise s throughthe ho le 2 in the perfo rate d ribbo n

,putting copper to lin e and zinc

to earth as in fig. 3,and this reve rsed curre n t acts upo n the

armature so as to take the w riting disc aw ay from the Mo rse slip,an d the do t is fin ished.

To comme n ce the dash,the marking-n e edle again rise s through

the ho le 3, putting zin c to lin e and coppe r to earth as in fig. 1 .

Z

L L £ £ L L E L £ L ! E L E L £

o n I2 as se ts can

The spacing-n e edle n o w rise s, but as it do e s n o t h it upo n aholein the pape r at 4 (fig. 7) the rod H do e s n o t push the dice D o ver,

WHEATSTONE ’S AUTOMATIC INSTRUMENT. 491

and as the rocking-beam V co n tin ues its ro cking mo tion the

po sitio n w ill be such as to place zin c to lin e an d coppe r, thro ughthe re sistan ce R

, to earth,and co n seque n tly a curre n t o f le ss

stre ngth passe s to lin e . Again the marking-n e edle rises,but as it

is o ppo sed by the paper at 5 (fig. 7) the disc D is n o t pushe d o verand the directio n of the curre nt is n o t alte re d.At last w hen the spacing-n e edle rise s thro ugh the ho le 6 , putting

copper to lin e an d z in c to earth, as in fig. 3,the dash is fin ished.

The marking-n e e dle n o w rise s w itho ut to uchi ng upo n aho le at7, the disc D is n o t pushed o ver, and, as the ro cking-beam V con

tin n e s its mo tio n, the po sitio n w ill be such as to place copper to lin e ,

and z in c, through the resistan ce , to earth .

IL— Ho w TO CLEAN THE INSTRUMENT.

Every mo rn ing the clerk in charge o f the in strumen t sho uldsubje ct it to athoro ugh o uter clean ing, by mean s o f duste r, brush,an d w ashleather. The con tacts sho uld be clean ed by an expe rie n cedhan d on ly . Paper dust in the slit under the star-w he e l and ro un dth e top o f the n e edle s must be removed w ith afin e brush.To clean the in side o f the in strume n t it must be take n to pieces,

but previous to this the proper po sitio n o f alldiffe ren t parts o f thein strumen t should be very carefully n o te d.

Allste e l parts are to be clean ed w ith w ashleather. Allpivo tho le s to be clean e d w ith hardw o o d and then o iled . All o the rparts, subject to friction , should be o iled as w e ll. If there is anybrass-coating on the pivo ts it sho uld be carefully removed w ith alittle emery paper .

Whe e ls, axle s, &c.

,are clean ed w ith brush , soap, and co ld

w ater, then dipped in to dilute spirits o f w in e , rubbed w ith fin e drysaw dust, and finally brushed w ithadry, clean brush ; o r still be tte r,brush the parts in dilute spirits of w in e , clean the te eth w ith cardboard, and finally brighte n w ith chalk, brush, and w ash-leather.

The co n tacts are clean ed as follo w s — Dust them w ith aso ft

brush and observe that n o hairs o f the brush are left be tw e en o r

about the co n tacts, the n scrape lightly w ith ablun t pen -kn ife . It

should be remembered that the co n tacts must n ever be scraped

492 ORIGINAL COMMUNICATIONS,

w ith a sharp in strume n t, as this w o uld so on w ear away the

platinum .

The pe n-kn ife , o r w hateve r e lse may be used

,should at the same

time act as ascraperand aburn isher.

When the tran smitter is to be take n to pie ces, first remove fromthe fro n t side o f the in strumen t1 . On e e nd o f each o f the spiral springs w hich pre ss the levers

again st the studs o f the ro cking-beam .

2 . T he small ring , w hich is fixed upo n the main axle .

3 . The pre ssing-dow n ro ller.

4. The star-w he el, and5 . The sto pper.

Whe n this is do n e , place the in strume n t on its back, take out

the fo ur main screw s, lift the fro n t w all, but w ith great care , and,if n ece ssary, lo o sen the tw o scre w s w hich fasten the in strumentupon the mahogany base .

When eve rything has be en w e ll clean ed,and it isascertain e d thatthe sw itch undern eath the in strument is in proper w o rking o rder,

putallparts in the ir right place , put on the fro n t side , an d w ith careguide every pivo t into its co rre spon ding ho le .

When areceiver is to be take n to pie ce s, first take o ff the ink

reservo ir, and allw o rking parts o n the o utside o f the fro n t ; as the

w o rking disc and the gro oved w he e l are n o t fixed w ith scre w s on

the ir axle s, they are easily remo ve d by mean s o f apair o f plye rs.Whe n this is do n e

,place the in strume n t o n its back, lo o se n the

w ire s to and from the e lectro -magn e ts, and finally take o ut and

clean the differen t parts.

The co n structio n o f the punche r, the be ll , an d the key is so

simple , and they are so easily taken to piece s and pu t toge theragain , that any particular advice o n this behalf must be co n sideredun n e ce ssary . Carefuln e ssand patie nce o n ly are require d.

111.— HOW TO WORK

,REPAIR

,AND REGULATE Tn E IN STRUMENT.

A.— T ke Pun cher .

The pun ching clerk sho uld w o rk w ith alight an d springy stroke .

It is o fte n fo und that, w he n o n e clerk co n side rs apun cher quite


B .— The Tran smitter.

This in strumen t is the mo st de licate and complicated part ofWheatsto n e ’

s automatic apparatus, and should there fore be treatedw ith the utmo st care .

The w in ding-up should n o t be do n e in sudde n je rks, as thisw ould en danger the chain .

The stoppe r should n o t be turn ed abruptly, o r struck fi'

om one

side to the o the r, but gen tly put in the po sitio n requ ired .

When the in strume n t do es n o t start run n ing imme diate ly afterthe sw itch has be en put o n sen d,” it sho uld n o t be fo rced to doso . A ge n tle turn o r tw o of the pre ssing do w n w he e l w ill ge n erallyhave the de sire d e ffe ct, but, if n o t, the in strume n t sho uld beexamin e d to find o ut the cause .

The chain sho uld n o t fall upo n the mahogany base w he n the

in strumen t is w o un d up .

Allcon tacts should be clean ed every morn ing.

When a tran smitter stops, the cause is gen erally o n e o f the

fo llo w ing1 . Dirt in the pivo t-ho le s, & c. To clean this properly the in stru

me n t must be take n to piece s.

2. Oil, dirt, &c.

,o n the frictio n discs. In this case the clo ck

w o rk run s ve ry un even ly , be cause the flyw he e l do e s n o t

m o ve alo ng w ith the o the r parts. The frictio n discs sho uldbe cleared carefully w ith w ash leathe r

,w hich may be do ne

w itho ut taking the in strumen t to pie ce s.

3. Wan t o f o il, w hich causes the clo ckw ork to run w ith aw hizzing n o ise . In such acase apply a drop o f Oilto each ofthe small pivo t-ho le s, w hich are fo un d o utside the in stru

me n taroun d m o st o f the pivo ts and the bearings o f the fly,

and at the same time put the clo ckw o rk to run at its highestspe ed .

The axle o f the pre ssing do w n w he e l be ing dry o r dirty,so

that the w he e l w he n lifted up from the ribbo n by depre ssingthe o ppo site e nd o f the frame do e s n o t run fre e ly fo r ago odw hile , after o n ce be ing starte d. Take o ff the w he e l

, clean

WHEATSTONE’S AUTOMATIC INSTRUMENT. 495

the pivo ts and the pivo t-ho le s w e ll, and apply adrop of o il,

but be sure n o t to turn the w he e l o ver, as each pivo t se ldomfits bo th ho le s.

5 . Paper rubbish o n o r abo ut the star-w he el, w hich preven ts then e edle s from passing fi'

e ely up and do w n . If the slits arequite cho ked w ith rubbish; the in strumen ts w ill sto p altoge ther

,an d this o f co urse can so o n be se en and remedied .

It is mo re dange ro us,ho w ever

,if the slits are n o t quite

filled up, as the clo ckw o rk the n may stillrun,but the

n e edles be ing slightly o bstructed the le ve rs w illn o t be ableto fo llo w the mo vemen ts o f the ro cking-beam

,and couse

quen tly the co ntacts be tw e en battery and earth are unce r

tain , and the signals w ill be lo st. Afte r remo ving the topof the fron t part o f the in strumen t

,the star-w he e l and the

slits are easily clean ed .

6 . The pivo t o fthe fly-w he e l axle having drilled aho le in to the

diamon d (agate ) . The o n ly remedy in this case is to put

o n an o the r spring w ith an ew diamo n d.

7 . The chain broke n . Whe n putting the chain toge ther againit must n o t be tw iste d. The co n n e cting link should bean n ealed befo re ben ding it, and tempered again afte rw ards.

Whe n any o bstruction is fe lt in w inding up the w e ight, the cause

w ill be foun d to be o n e o f the follow ing1 . The stopping co n trivan ce at the back o f the in strumen t do e s

n o t readily sink do w n as the w e ight go es do w n, and the re

fo re it co n tin ue s to stop. Fo r a single time the stoppe rmight be depre ssed by mean s o fakn ife o r the like , bu t itis advisable to have the co n trivan ce properly clean ed ato n ce .

2 . The main axle dry , dirty,and rusty . First remove the drivingw e ight, take out the ho le w he e l

,toge the r w ith the axle

,

from behin d the in strume n t, then fo rce the axle out o f the

w he e l, if n e eded by hamme ring ; o n that e nd o f the axlew here the w in ding-up handle is put o n , but befo re usingthe hammer, allrings, screw s, &c.

,fixed upo n the axle must

be take n Off.

3 . When w inding up the w e ight the chain falls upo n the in stru


men t’s base , in stead o f go ing through the ho le i ntendedfor

it. The edge o f the ho le sho uld be ro un ded o ff,so as to

cause n o o bstructio n , but at the same time it should beascertain ed that the fo rked brass pie ce w hich is meant fortaking the links o ff the cams is in its pro pe r po sitio n .

The tran smitte r is regulate d by mean s o f1 . The tw o scre w s again st w hich the n e edle s M and S are

pre ssed.2. The spring upo n w hich the ro lle r E is fixed.

3 . The tw o in sulating co lle ts K,K’

,are the rods H and H’

, and

4 . The scre w above the ebo n ite pie ce e .

It is to be observed that the side w ay movemen ts o f the disc Dsho uld re semble the w riting w ith the Mo rse key, and be in accordan ce w ith the marks o n the pe rfo rated ribbo n .

Whe n regulating the tran smitter, put it in circuit, w ith agoodrece ive r

,andafew ce lls.

C . The R eceiver.

This in strume n t is n o t quite so complicated as the tran smitter,but n eve rthe le ss it o ught to be handled w ith care . The w indingup should be do n e w itho ut je rking.

If the clo ckw o rk do e s n o t start run n ing immediate ly after gentlyputtin g the stoppe r in to the pro pe r po sitio n , aslight pull at the

pape r slip ge n e rally has the de sired effe ct.

It sho uld be asce rtain ed that the Slip is draw n o ut o f the box

w ithout an y Obstructio n,and that the re ce ived marks are imprinted

o n the convex side o f the slip,w hich is Of particular impo rtance

w he n the re ce ived slip is paste d upo n the me ssage fo rm . As the

pape r ro lls are cut after be ing w o un d up, and co n se que n tly the cutstarting at the outside , aslight be n d w ill alw ays be pro duce d.

When the clo ckw o rk stops, the cause w ill be fo un d to be similarto that w hich is po in te d o ut fo r the tran smitte r. The clo ckw orkmay stop, be cause the Oilaround the spring (in the dr um) has beenused up o r has be come dirty , in w hich case le t the spring run o ut,

take o ff the fro n t w all o f the in strum e n t,w he n the drum w ill

readily come o ut, then unscre w the drum-cove r and put o n afreshsupply o f o il.


[ f or the Re ceiver

ldrum w ith spring and axle .

3 springs.3 sto pping co n trivance s (brake levers).1 do zen springsand agate s fo r the fly-w hee l.4 small axle s.

chain s.

2 spirals for the fly-w he e l .3 w riting discs.

3 larger discs w ith gro o ves.

Fo r the Transmitter

5 do zen chain s.

i star-w he els to move the perforated pape r-shp.

2 Spirals fo r the fly-w hee l.4 do zen small axles.1 springs w ith agate s fo r the fly-w hee l.Platinum fo r Con tacts — Spiral Springs o f differe n t size s.

For the B ell

2 sets o faxles .

4 springs.2 drums w ith axle .

Shiraz, Persia,To the Secretary, 20 July, 1876 .

Society o f Te legraph Engin eers.

SIR ,— In examin in g the discordan t re sults co n tain e d in Mr .

Grave s’s paper “On the In ternal Re sistan ce o f Batte rie s (vol. ii .

pp. 130 I find that theyare due to an o versight in w orkin go ut the datathere given .

By substituting the fo rmulaa:g (s S)

used in repro ducing the defle ctio n ), the apparent discrepan cie sw ill disappear.

CORRESPONDENCE. 499

Fo r example , take the first lin e in each se t, page 132, for shun ts1 an d 3 ohms re spe ctive ly

12000 x 1 x (5854 5-86)5854 x 1)

2471 ;

2360 x 3 x2478

And again , page 1335600 x 1 x (5854 5 86) 1153

1100 x 3 x (58541155

5854 x (5 86 3)

the re sults in each case , w ith a shun t o f 1 and 3 ohms,be ing

iden tical.Yours faithfully

,

J . J . FAHIE .

To the Secretary, Valen tia, October 25th , 1876.

Society o f Te legraph Engin eers.

S1R,

—In re feren ce to Mr. Fahie ’s commun icatio n , permit me to

State that w hen I made tho se experime n ts in 1873 the discrepan cie sin the results w e re so striking that I w as induce d to sen d them to

the So cie ty in the hope that some o n e might be able to re co ncilethem.

After alapse of upw ards o f thre e years Mr. Fahie has kin dlysupplied aformulaw hich comple te ly clears the groun d, and re co n

ciles apparen t co n tradictio n s, and it is satisfactory to have thusproved that Nature

’

s law s are true , ho w ever e rro n e ously w e areliable , at times, to in terpre t them .

Yo urs faithfully,J. GRAVES.

The Eastern Te legraph Company Limited,To the Secretary, May lst, 1877.

Socie ty o f Te legraph Engin eers.

DEAR SIR ,— Please allo w me to draw youratten tio n to aprin ter’

s

erro r w hich appeared in the So cie ty’s Jo urnal, No . XIII.and XIV .

2 x 2


vol. v . page 254,co n tain ing my paper o n A n e w me thod of

taking the Lo op Te st. ” At fo o t of page 254 yo u w ill find

Y ("12 3 1 3 9 Y

”

2 111 3 2

in stead o f the follo w ing, w hich it should have be enX

0

Y

The m istake be ing in the small figure s attached to r and R.

I should fe e l much obliged if yo u can draw atte n tion to the abovein your n ext n umber.

I am,dear Sir, yours faithfully,

ANDREW JAMIESON,Ele ctri cian .

s.s Chiltern , Malta.

BELL’S TELEPHONE.

With the obje ct o f stimulating inquiry in to the mean s o f im

proving the te lepho n e Of Mr. Be ll,w hich is the mo st beautiful

adaptatio n o f te legraphy eve r made,I de sire to draw atte n tio n to

afe w Simple m e tho ds by w hich any o n e may satisfy himse lf o f its

practicability , fo r n o o n e having w itn e ssed its pe rfo rmance can failto se e agreat future befo re it.The reco rder o f Sir W. Thomso n affo rds a ready m ean s o f

speaking, and give s o ut such clear to n e sas to make the liste n er atfirst in vo lun tarily lo ok fo r the speaker behin d the in strum e n t (w ho

may be m ile s aw ay) . It suffice s to take a tube tw o in che s indiame te r, and stre tch o ver o n e e n d am embran e o f parchme n t or

thin gutta-percha(the latte r is le ssaffe cted by the breath , the fo rmerbe coming some w hat flaccid afte r atime ). To the ce n tre o f the

m embran e cemen t astraw, and fix the tube in fro n t o f the in stru

me n t ; abo ut six in che s from the “mo vable co il ceme n t the o there nd o f the straw to the co il at the po in t w here the silk fibre is


avo ice at adistan ce —and the nearer you seem to bring the soundthe bette r your adjustment, and vice versa‘.I have Spo ken through four kn o ts of buried cable w ithout sensi

ble dimin utio n o f effect.Whe n the in strumen ts are n o t w e ll adjusted some w o rds w ill

come clear w hen o thers do n o t, and I have fo un d the se n te nce

are you ready,

” pro noun ced de libe rate ly, in telligible w heno thers w ere n o t.

The Object '

to be sought fo r is to augmen t the strength o f the

variatio n s of curren t. At prese nt it is limited by the po w er of

the vo ice to move an armature or co il, and un less it can be magn ified by putting in play areserve o f fo rce , as compre ssed air, &c. ,improveme n t cann o t go far.

The mo st hopefulfie ld seems to be the effe cting avariationthrough asen sible range of resistan ce at the se nding and to varythe strength o f curren t in aprimary co il by shun ting o r varyingthe re sistan ce o f abattery circuit— as for example a fin e w irein serted mo re or less in mercury.

St. Pierre , M ique lon ,March 24th , 1877.

ABSTRACTS AND EXTRACTS .

TRANSMISSION OF MUSICAL TONES BYELECTRICITY.

Although much has been said and w ritten o f late o n the subjecto f soun d tran smissio n by e le ctricity and its applicatio n to te legraphy, the re still remain s much o f in te re st to be said.

As soun d tran smissio n , e le ctrically, is like ly to play an impo rtan tpart in the te legraph o f the futu re , it w ill be o f in te re st and impo rtan ce , e spe cially to te legraphers, to have an in te lligen t un derstanding o f the prin ciple s invo lved.As far back as 1837 Page discovered that the magn e tisation or

demagn e tisation o f soft iron w as accompan ied w ith sound. Aboutthe same time Professo r Henry studied the acoustic effe cts o fa

galvan ic curren t upo n an e lectro-magn e t, and de te rmin ed that itw as due to the e longation and con traction of the iron , and n o t the

attraction o f o n e limb o f ahorse sho e magn e t for the o ther,as at

first suppo se d. He dete rmin ed this by making astraight magn etpro duce the same effect as the ho rse sho e shape .

This discovery stimulated research among the scie n tific me no f Euro pe for afe w years, but w ithout making any great advan cein the scie n ce of te lepho ny. We rthe im’

s apparatus fo r producingasimple ton e in an iro n rod by an automatic rhe o to n e

,and that o f

R e is, w hich tran smitted ton e s differing in pitch by mean s o fadia

phragm‘

thro w n in vibratio n by the vo ice,w e re

,pe rhaps

, the

furthe st advan ce in the w ay o fapparatus in that lin e un til w ithin avery few years. They w e re used as me re scien tific toys. NO

attempt, or at least n o succe ssful attempt, w as made to adapt this

504 ABSTRACTS AND EXTRAUI‘

S.

discovery to any of the usefularts o r industries. In fact,further

research and disco ve ry w ere n ece ssary before it cou ld be so

adapted .

Within the last fe w years aspirit o fre-inve stigatio n an d furtherdiscovery has started up, and, as in the first instan ce

,it starts in

o ur o w n coun try.

As abo ve stated, befo re this prIn p le o f sound transm issio n couldbe applied eco n omically and practically for te legraph ic purpo ses,there remain ed much to be discovere d and much to he inve n ted, inthe w ay o f de tails o fapparatus and me thods o f conn ecting the same

to the lin e an d batterie s, as w e llas the disco ve ry o f more funda

me n tal prin ciple s. All this w as n e ce ssary before the pre sentcapacity o f the system w as attain ed— that o f tran sm itting e ightme ssage s simultan e ously through aSingle w ire .

This re sult has be en accomplished by ElishaGray,o f Chicago,

an e le ctrician o f large experien ce as an inven tor and con structor of

e le ctricaland te legraphic apparatus.

P ropagation of aSound Wave.

Every-o n e has w atched the expan ding ring produced by apebbledropped in asmo o th she et o f w ater. Now

,imagin e aglobe in

the air starting from acommo n ce n tre an d expanding un iformlyin eve ry directio n at the rate o f fe e t per se co n d

, and you

have apicture o f the air w hen asingle sound w ave o r pulse passesin the o rdinary w ay . The w ave is set go ing by some force exer

cised at the starting po in t, as, fo r in stan ce , an explo sio n . The

heated ce n tre expands vio le n tly in eve ry dire ctio n,fo rcing the first

layer o r she ll o f air particle s again st the seco n d,w hich in turn

delivers up its blo w to the third,and so o n to infin ity. Whe n the

she ll o f particle s n ext the tympan ic membran e o f the ear is reachedit vibrate s by the blo w ,

and con veys to the brain the se n satio n of

soun d .

An ae rial w ave and an e lectrical are analago us in some re spectsand ve ry diffe re n t in o the rs. As w e have in timated be fo re

,iron

e lo ngate s w he n magn e tized an d sho rten s w he n demagn e tize d. If,

an iro n rod, surro un ded by ahe lix, is moun ted upo n aso un d-boardand magn etized by clo sing abattery through the he lix

, adistinct


to its po sition in the scale . On e end is rigidly fixed to the post b,w hile the o ther e nd is left free , and is actuated by alocal battery.

The magn e ts e andfare arranged in the same local circu it, magnet

f having are sistan ce o f about thirty ohms, and magn e t e aboutfo ur ohms. When the reed a is n o t in vibration the po in t G is ine lectrical con tact w ith it, w hich throw s ashun t w ire en tire ly aroundthe magn e t f ; thus, practically, the w ho le o f the lo cal currentpasse s t hrough magn e t e at the in stan t o f clo sing the key 0 . It is

w e ll kn o w n that w hen tw o e lectro-magn e ts are place d in the same

circuit the o n e w hich has the higher re sistan ce (o ther thin gs be ingequal) w ill deve lope the stro ngermagn e tism , and that, if the magn eto f highe r re sistan ce be take n o ut o f the circuit

,the f orce o f the

o ther w ill be in creased. ‘Vhen the key 0 , be ing depre sse d, clo sesthe lo cal circuit at d, the operatio n o f the re ed is as fo llo w s : The

w ho le o f the curre n t from batte ry L passe s thro ugh the magn e t e,w hich attracts the re ed

,say w ith apo w e r o f fo ur . Wh e n the reed

has moved to w ards I far e n o ugh to leave the po in t G, the shunt

circuit is broke n , and the curre n t flo w s thro ugh bo th the magn ets.Immediate ly the po w e r in f rise s from ze ro to five

,and that o f e

drops from four to o n e, and the re ed is attracted to w ardsf w ith an

TRANSMISSION OF MUSICAL TONES BY ELECTRICITY.

e ffe ctive force o f four, un til con tact is again e stablished w ith thepo in t G. The operation is repeated at arate de termin ed by theSize and length of the reed, and w hich correspo nds w ith the flmdamen tal o f the n o te it repre sen ts. The figure s give n above onlyapproximate the facts . The re latio n o f the magn e ts as to size andresistan ce , so as to give an equal impulse to the re ed in bo th dire ctio n s, w as determin ed by actual experimen t w ith abatte ry o fa

given size .

Fig. 1A.

It w illbe o bserved that by this arrangeme nt the cen tre o f vibratio n co incides w ith the ce n tre of the re ed w hen at re st, so that thepitch of the to n e is n o t disturbed by any o rdinary change o f

battery, as is liable to be the case w hen o n ly o n e magn et is used,o r w hen the impulse is n o t e qual in bo th dire ction s.

A se co nd battery, w hich w e w ill call the main batte ry, is co n

n ected as fo llo w s : On e po le is co n n e cted to the gro un d ; theo ther run s to the in strumen t, and, en tering at binding-screw 4

(fig. 1a), run s to the po in t H of key C ; from key 0 to po in t I,

w hich makes co ntact w ith the re ed a; from re ed ato binding


screw 1, and then ce to lin e . It w ill be seen that w hen the key is

at rest the batterie sare o pen at the po in ts d and H.

Allthe keys in the in strumen t, w he ther o n e o r mo re o ctaves,have co rre spo nding re eds and actuating magn e ts

,the o nly differ

e nce be ing in the tu ning o f the re eds. The re is but o n e main ando n e lo cal battery used

,and the co n n e ctio ns to each key are run in

bran ch circuits from the binding-scre w s,as Show n in fig. la. But,

since allthe se bran che s are ope n at the key po in ts, n e ithe r o f the

batterie s is clo sed un le ss akey is depre ssed.

If n e w the keys are man ipulate d, atun e may be played w hich isaudible to the playe r. When any key is depre sse d , the localbattery sets in vibratio n its co rrespo nding re ed, w hich so un ds itso w n fundamen tal n o te acco rding to the law o f aco ustics. SO far

the in strume n t is an e le ctrical o rgan , the mo tive po w e r be inge le ctricity in stead o fair. The main battery has had n o part w hatever in its o peratio n .

If,ho w eve r

,the main circuit is clo sed by comIecting the distant

e nd to ground,and the po in t I is properly adjuste d, so that it

makes and breaks co n tact w ith the re ed at each vibration,ase ries

o f e le ctrical impulse s,or w aves, w ill be se n t through the lin e ,

co rre spo n ding in number pe r se co nd to the fundame n tal of there ed .

No w,as the pitch o f any musical to n e is de termin ed by the

n umbe r o f vibratio n s per se co n d made by the substan ce fromw hich the so un d pro ce eds

,it is clear that if the se e lectrical w aves

can be co nverted in to audible vibratio n s at the distan t e n d o f the

lin e,w hether it be o n e mile o r five hundred mile s from th e player,

the n o te produced w ill be o f the same pitch as that o f the se ndingre ed .

On e me thod o f converting the se e lectrical w ave s in to audiblesoun d at the re ce iving end has be en de scribed— that o f the mo un ted

e lectro -magn e t. When it is prope rly mo un ted,so as to give the

best acoustic effect, the to n e is very lo ud, if the lin e is n o t to o longo r the batte ry to o w eak.

Fig. 2 sho w s o n e o f Mr. Gray’s musical rece ivers. It is a

w o oden box, w ith ho le s fo r acoustic effe cts,and having m oun ted

upo n it acommo n e le ctro -magn et, w ith aheavy armature made


w ould glide along the side fo r ashort distance . At these timesl

n o ticed asound pro ce eding from under his hand at the po int ofcon tact, w hich se emed to have the same pitch and quality as thato f the vibrating e lectro tome , w hich w as w ithin hearing. I immediate ly to o k the e le ctrode in my hand, and, repeating the operatio n

,to my aston ishme n t found that, by rubbing hard and rapidly,

I could make amuch louder soun d than the e lectro tome was

making. I the n changed the pitch o f the vibratio n,in creasing the

rapidity, and foun d that the pitch o f the soun d un der my hand wasalso changed

,it still agre e ing w ith that o f the vibratio n . I then

mo isten ed my hand and co n tinued the rubbing, but n o so und waspro duce d SO lo ng as my hand remain ed w et ; but as so o n as the

parts in co n tact became dry the sound reappeared, e a a

Fo llow ing out the ideasugge sted by the bath-tub experiment,I co n structed vario us device s w ith me tallic plate s fo r re ce iving thetun e by rubbing w ith the hand. A very co n ven ie n t m e thod fordo ing this is Sho w n in fig. 3.

This in strumen t has ametal stan d o f sufficien t w e ight to ke ep itin po sitio n w hile be ing man ipulated. Upo n the stan d aho rizontalshaft is moun ted in bearings, upo n o n e e nd o f w hich is acrank,w ith ahandle made o f some in sulating substance . Upo n the o ther

e nd is cen tred athin cylindrical so unding-box,made o f w o o d

,the


face o f w hich is covered w ith acap made of thin metal, spun in to aco n vex form to give it firmn e ss. This box has an open ing in thecen tre to in crease its son orous qualitie s. The metal cap is ele ctrically conn e cted to the me tal stand by mean s o faw ire .

If the ope rato r conn e cts the cap, through the stan d, to the

gro un d, and taking ho ld of the end o f the lin e w ith o n e han dpresse s the fingersagain st the cap, w hich he revo lves by mean s o fthe crank w ith the o ther hand, the tun e that is be ing played at theo ther en d of the lin e become s distin ctly audible , and may be heardthroughout a large audie n ce ro om . If the co nditio n s are allperfe ct, the faster the plate is revo lved the louder w ill be the music,and the slo w er the motio n the softe r w ill it become . When themo tio n stops the sound en tire ly ceases.

I have found that e lectricity o f con siderable ten sio n is n eededto pro duce satisfactory results, at least that o f fifty ce lls o f bat

tery . The n e ce ssary degre e o f ten sio n is mo st co n ve n ie n tly oh

tain ed by passing the lin e curren t through the primary circuit(adapted to the circuit w here in it is used) o f an inductio n co iland con n e cting the re ce iver in the seco n dary circuit.I n o ticed that w hen revo lving the plate w ith my finger in co n tact

the friction w as greater w hen a n o te w as sounding. I thencon n e cted 9. smallRuhmkorff co il to abattery, in serting acom

mo n te legraphic key in the primary circuit, in stead o f the se lfacting circuit breaker. I conn ecte d on e e nd o f the seco ndary co ilto the me talplate , and ho lding the o the r e nd in my hand I rubbedthe plate briskly, and had my assistan t slow ly making do ts w iththe key . I n o ticed at each make o f the circuit aslight soun d

,and

at each break avery much lo uder o n e,o w ing to the fact that the

terminal se co ndary w ave is much more in te n se than the in itial. I

n o w he ld my hand still, and, w hile I could fe e l the shock just asdistin ctly as before , there w as n o audible sound

,pro ving that the

mo tio n w as an e cessary co ndition in its pro ductio n . The se n satio nw hen the soun d w as produce d w as as though my finger had sud

denly adhered to the plate and then as sudden ly let go , producingaso un d.The n ext experimen t w as w ith o n e hundred ce lls o f gravity bat

tery. I conn ected on e po le to the plate and he ld the o ther in my

5 12 ABSTRACTS AND EXTRACTS.

hand, pre ssing my finger again st the plate and re vo lving it asbefo re . I in serted athin pie ce o f paper be tw ee n my fingersandthe plate to preve n t painful effe cts from the curre n t

, and myassistan t made clashes w ith akey in the circuit. I w as thusableto n o tice the effect o f an impulse o f lo nger duration . When thekey clo sed there w asaperceptible in crease o f the frictio n , so thatmyfinge r to ok apo sitio n further forw ard on the plate , w he re it w ouldremain as long as the circuit remain e d clo sed. As so o n as the keyw as ope n ed my finger suddenly dropped back o n the plate , makingthe same n o ise I had before heard. This o peratio n w as re peated soo ften that the re co uld be n o que stio n as to the effe ct it pro duced.From the fo rego ing expe rimen ts I find that the fo llowin g con

ditio n s are n e ce ssary to reproduce musical ton es th rough themedium of an imal tissue by mean s o f e lectric w aves tran smittedthrough ate legraph w ire1st. The e le ctrical impulses must have considerable ten sion in

o rder to make the effect audible .

2nd. The substan ce used for rubbing the re ce iving plate mustbe soft and pliable , and must be aconductor of e le ctricity up to

the po in t o f co n tact,and there are sistan ce must be in terpo sed, verythin — n e ithe r to o great n o r to o little .

3rd. The plate and the han d o r o ther tissue must n o t o n ly be inco n tact, but it must be arubbing o r gliding co n tact.4th . The parts in co n tact must be dry, in o rde r to pre serve the

n e ce ssary degre e o f resistan ce .

”

W e have n o w to co n sider,first

,the tran smissio n o f compo site

to n e s ; and, seco ndly , the analysis o f them,and the ir application

to multiple te legraphy .

R efe rring to the cut (fig. 1) it w ill be se e n that in this in strumen t the re are aserie sLo f keys co n n e cted w ith ase rie s o f re e ds

,or

ele ctro tome s,tun ed to the musical scale . If the batte rie sare properly

co n n ected to the in strumen t,and e ithe r o f the tun e -re ce ivers

de scribed be placed in the lin e , n o t o n ly w ill the to n e o f any single

key but to n e s from aseries o f keys be reproduced simultan e o usly,sho uld they be o perated at the same time

,w he ther the re sult o f the

combination be co n co rdan t o r disco rdan t. If allthe keys co rre

spo nding to an o ctave o f to n e s be depre ssed simultan e o usly,the


“Fig. 4 is aperspective of o n e fo rm of arece iving in strume nt,called an analyse r. The con struction o f the in strume n t is verysimple . It co n sists o fan e le ctro -magn e t, adapte d to the resistanceof the circuit w here it is in te n ded to be used, and o f aste e l ribbonstrung in fro n t o f this magn e t in aso lid me tal frame , an d pro videdw ith atun ing screw at o n e end so as to readily give it the properte n sio n . The le ngth and size o f the ribbo n depe n d upo n the n ote

w e w ish to re ce ive upo n it. If it is ahigh n o te, w e make it

thinn er and sho rte r ; ifalow n o te,w e make it thicker and lo nger.

If this ribbo n is tun ed so that it w ill give acertain n o te w he n madeto vibrate mechan ically, and the n o te w hich corre spo n ds to itsfundamen tal is then tran smitte d through its magn e t, it w illre spondand vibrate in un iso n w ith its tran smitte d n o te ; but ifan o the r n otebe sen t w hich varie s at allfrom its fun damen tal it w ill n o t re spond.

Ifacompo site to n e is sent the ribbo n w ill re spo n d w he n its ow n

n o te is be ing sen t as apart of the compo site ton e , but as so o n as its

o w n ton e is left out it w ill imme diate ly stop. Thus I am able tose le ct out and in dicate w hen any n o te is be ing se n t, in fact to

analyse the to n e s w hich are passing over the lin e .

”

The great obje ct to be attain ed in the co n structio n o f sucharece ive r is to rid it

,as far as po ssible

,o f allso un d-board qualities,

w hich w ould cause it to respo n d alike fo r allto n e s,and augment,

as far as po ssible , its ten den cy to vibrate for ace rtain to n e o n ly tow hich it is tun ed . An o the r me thod is sho w n at fig. 5

, w hich com

bin e s atun ed re ed, o r bar o f ste e l,w ith are sonan ce box.

The co n structio n is as fo llo w s : Suppo se w e w ish to co n structa

re ce ive r to re spo nd to ato n e made by 128 vibratio n s pe r se co nd.W

'

c first make abox in the fo rm o f aparalle logram,as sho w n in


the m“, w ith o n e open end. The box is made the right size topro duce amaximum resonance o f the desired tone . Upo n this bo xis mounted firmly o n e po le is faste n ed o n e

end of asw elbar having paralle l side s, w hich exte nds acro ss th eo the r po le , but do e s n ot touch it. This po le , for co nven ien ce , ismade adjustable . The tuning is alldo n e at o n e po in t

,n ear the

fixe d e nd of the bar, by filing aw ay un til it w ill vibrate 128 times

pe r se co nd, if excite d mechan ically. When thus tun ed and

moun te d, if by any mean s the bar is thro w n in vibratio n , it w ill becommun icated to the walls o f the box

, w hich in turn move theair in the box, and the re sult . is amusical to n e issuing from its

mo uth. In te legraphing this e ffect w ill be pro duced, w he n e lectrical impulses are sen t through the w ire o f the magn et, at the rate

o f 128 times per se co nd. If amuch greater o r less rate is sen t

thro ugh the magn e t n e ither the bar or box w ill respo nd. If n ow

w e make an o ther receive r in allrespe cts like the o n e described,

exce pt that the bar and bo x are tun ed to re spo nd— say w hen 200impulse s pe r se con dare se n t through it— it w ill be practically sile n tfo r the 128 series, but w ill speak out plainly fo r its o w n rate— 200

per seco n d. If the tw o rates o f vibratio n o r impulses are sen t

simu ltan e ously, bo th boxes w ill speak, but each adifferen t to n e .

If w e ste p the sending of o n e rate and n o t the o the r,the o n e re

ce iver made to respo nd to that rate w ill sto p so unding.

Ifat the sen ding end the transmitted n o te s are cut up in to lo ng2 L 2


and sho rt so unds , represe n ting the Mo rse code , w ith acommon

te legraphic key , each se t of signals w ill be heard on its re spectiverece ive r w ithout in terferen ce w ith each o ther.

Still an o ther fo rm o fanalysing re ce iver is sho w n at fig. 6 . Thisco n tain s allthe esse ntial parts of the last-de scribed in strument,w itho ut the re so nan ce box, but has an additio nal attachme n t

,by

w hich acommo n sounder o r recording instrumen t is w o rked bymean s o falo cal circuit. In this in strume n t t he magn e t is mou nted

upo n an ordinary base , and is provided w ith atun ed re ed o r bar ofdefin ite pitch— the same as the last described rece iver. On top of the

fre e end of the bar is aplatinum po int, slightly concave , so as to

form asmall cup fo r o il. Resting on this cup is aplatinum po intattached to alight leve r w hich is pivo ted at the o the r e n d. Thislever is provided w ith africtio n slide

,so that its balance can be

readily changed from light to heavy . This lever is so balan ced thatits natural rate o f vibratio n is slo w er than that o f the bar . Asa

co n seque n ce , w he n the bar is thro w n in vibratio n the po in t o f theleve r is n o t able to fo llo w ,

and so rattle s o r jars in the small cup.Ifaso unde r and lo cal battery are co n n ected to it

,so as to make

the bar and leve r apart o f the circu it, each time the bar is thro w nin vibratio n the circuit is practically open ed

,and the soun de r lever

falls o n its back po in t. As so o n as the vibratio n cease s the po intstops jarring, the circuit is e stablished

,and the sounder clo se s. If

the vibration is be ing in te rrupted at the sen ding end o f the lin e byaMo rse key, the effect o n the soun der is the same as tho ughare lay w ere in circuit in stead o f -the analyser. This is pro bably the


rece ivers, w ith the ir co n n e ctio n s. The lo calcircuits, w ith the irmagn e ts, are left o ff to avo id co n fusio n .

A and B repre se n t tw o transmitters, placed at o n e en d of a

lin e ; A’

and B’

,tw o re ce ivers at the o ther e nd. On e e nd o f the

main battery is co n n e cted to lin e and the o the r end to ground.

Each tran smitter is placed in ashunt-w ire , runn ing from its mainbattery comi ectio n s around o n e-half of the batte ry. A common

ope n circu it key is placed in each o f these shun t-w ire s. Suppose

n o w the tw o reeds o f A and B to be sounde d, A making 264vibratio n s per se cond

,and B 320, just tw o to n e s or amajo r third

above A. So long as the keys remain ope n the battery is allonthe lin e steadily. If the key o f tran smitte r A is clo sed

,half of

the battery is be ing thro w n o n and o ff the lin e at arate o f 264

time s pe r se co nd. This cause s asucce ssio n o f e lectrical w aves toflow thro ugh the lin e at the same rate . If n e w the ste e l ribbo n of

the analyse r A has be e n tun ed in un ison w ith the se e le ctri calw ave s it w ill re spo n d and hum the same note as the tran sm itter ;but if it is n o t in un iso n it w ill remain practically quie sce n t, sothat the n o te can o n ly be heard by submitting it to the mo st de licate te st. To bring it in un iso n it is o n ly n e ce ssary to turn the

Fig. 8 .

tun ing-screw up o r do w n, as the case may be . When the funda

me n tal o f the ribbo n co rrespo nds w ith that o f the se nding-re ed, it


an n o un ces the fact by sounding o ut loud and full. If (having thekey of tran smitte r A still clo sed

,and

,co n seque n tly, its co rre spo n d

in g analyser still sounding) w e clo se the key be lo nging to tran sm itter B , the o ther half o f the batte ry w ill be throw n o n and o ff

the lin e at the rate o f 320 time s per seco n d, and an o ther succe ssio no f e lectrical w ave s w ill flo w thro ugh the lin e

,this on e be ing at the

rate o f 320 time s per secon d. If the analyzer B is in proper tun e ,so that its fundame n talis the same as that o f its corre spo ndingtran smitte r B ,

it w ill hum its n o te as lo ng as the key is clo sed,making acho rd w ith A’

. In the same w ay agreat number o f

differe n t n o tes may be sounding at the same time at o n e e nd o f a

te legraphic lin e , and be heard simultan e ously at the o ther e nd,

each n o te soun ding upo n adifferen t re ce iving in strumen t.”

Of co urse , any o f the thre e re ce ive rs de scribed w ill operate inthe same man n er. The above diagram sho w s o nly tw o se ts o f

apparatus, but the system admits o f many mo re . Eight me ssage s— fo ur each w ay— have already be en se n t and re ce ived simultan e o usly through a single w ire betw e en Ne w Yo rk and Philade lphia, fo r an umber o f days.

In w o rking bo th w ays,amain battery is used at bo th en ds, and

divide d in to as many sectio n s as there are to n es used . The rece ivermay be placed in abridge o r w o und differen tially

,as in duplex.

The re are many applicatio n s yet to be made o f this system .

Already Mr. Gray has applied it to aprin ting system w hich is ato n ce rapidand re liable , and if in ge n e ral use w o uld greatly reducethe labo ur required to do agiven amoun t o f busin e ss

,as w e ll as the

n umbe r o f w ire s — Extracted from The Telegrapher.

”

BELL’

S ARTICULATING TELEPHONE.

Attempts have be e n made fo r many years past to tran smit

musical o r articulate sounds to adistan ce by mean s o f e lectricalcommun icatio n , and some o f the early experimen ts o f the late Sir

Charle s Wheatsto n e w ere accompan ied w ith so much succe ss that

it w as hoped that atime w ould come w hen.

an in strumen t might

be co n structed n o t o n ly to register graphically certain audible


so un ds but to produce upo n adiagram ase t o f signs by w hich thesounds o f the human vo ice could be reco rded ; in o ther w o rds, thatit might be come po ssible to co n struct an automatic repo rter ; and inthe Loan Co llectio n o f scie n tific apparatus at South Ke n sin gtonmay be se en several in strume n ts bearing upo n the se re searches,and in w hich the vo w e l sounds are reco rded by aserie s o f dis

tin ctive curve s.In the year 1860, Phip Re iss

,o f Friedrichsdorf, n ear Hom

burg,fo llo w ing the researche s o fWe rthe im

,Marian , an d He nry

upo n the productio n o f sounds by e lectricity, inven te d the te lephonew hich bears his name , and w hich also may be se e n at South Ken

singto n . The te lepho n e o f Re is is o f tw o parts ; atran sm itting instrumen t and a re ce iver. The fo rme r co n sists e sse n tially o f a

stre tched membran e , w hich, by vibrating in un iso n w ith the impulse s it rece ive s from musical so unds played n ear it, tran sfo rms

those impulses in to aserie s o f e le ctrical curre n ts byasimple makeand-break arrangeme n t, and these currents acting o n the re ce ivingin strumen t, w hich may be hundreds o fmile s distan t, re pro duce theco rre spo nding n o te s, so that atun e played at o n e statio n can be

distin ctly heard at the o the r.

The rece iving in strume n t is fo un ded upo n the w e ll-kn o w n phe

n eme n ou discove red by Page in the year 1837,that adistinct

so un d accompan ie s the demagn e tisatio n o f an iro n bar place d in ane lectro -magn e tic he lix. It co n sists o f aso ft iro n bar abo ut the sizeo fakn itting n e edle

,surro unded by ahe lix o f w ire w hich forms

part o favo ltaic circuit w ith the tran sm itting in strum e n t, an d for

in te n sifying the effe ct bo th in strume n ts are provided w ith so rmding

boards,o r re so nato rs. From the abo ve de scriptio n it w ill be se en

that ifan o te w hich make s (say) o n e hun dre d vibrations pe r se co nd

be soun ded in the n e ighbo urho od o f the tran smitting in strume n t,

its m embran e w ill make o n e hun dred co rre spo n ding v ibratio ns,making and breaking the vo ltaic curren t o n e hundred time s

,and

producing o n e hu ndred demagn e tisatio n s in the rece iving in strume n t fo r every se co nd o f time

,so that exactly the same n o te that

w as sounded in the tran smitte r w ill be audible at the distan t statio n .

It is obvio us that the duratio n o f,and time be tw e e n , tw o n o te s must

be iden tical at bo th e nds o f the con ducting w ire,and thus is re


Re iss and Gray, co n sists o f tw o parts , atransmitting in strumentand are ce iver, and o n e cann o t but be struck at the extreme sim

plicity of bo th in strume nts,so simple inde ed that w e re it n o t for

the high authority o f Sir William Thomso n o n e might be pardoued at en te rtain ing some doubts o f the ir capability o f producingsuch marve llo us re sults.

The transmitting in strume n t, w hich is represe n te d in fig. 1,

co nsists of ahorizo n tal e lectro -magn e t,attached to apillar about

2 in chesabo ve ahorizo n tal mahogany stand in fro n t o f the poles

o f this magn e t— o r,mo re co rrectly speaking

, magn e to e lectricinducto r— is fixed to the stand in avertical plan e a circular brass

BELL’S ARTICULATTNG TM HONE. 523

small oblo ng pie ce of so ft iro n , w hich plays in fro n t o f the in ducto rmagn e t w hene ve r the membran e is in a state o f vibration . Th ismembran e can be tighten ed like adrum by the thre e m ill-headedscrew s sho w n in the draw ing. The e nds o f the co ilsurroun dingthe magne t te rminate in tw o bindin g-scre w s, by w hich the in strument is put in circu it w ith the rece iving instrume n t

,w hich is sho w n

in fig. 2 . Th is in strume n t is n o thing more than o n e o f the tubularelectro ~mngne ts inve n te d by M. Niclés in the year 1852 , but w hichhas be en t e-invente d unde r vario us fancy name s ‘

se veral timessin ce . It co n sists o f avertical bar e lectro -magn e t inclo sed in atube o f so ft iro n , by w hich its magn etic fie ld is co nden sed and itsattractive po w er w ithin that area in creased. Over this is fixed

,

attached by ascrew at apo in t n ear its circumfere nce,athin she e t

iro n armature of the thickne ss o f ashe e t of cartridge paper, andthis w he n under the influen ce of the tran smitte d curre n ts actspartly as avibrato r and partly as aresonator. The magn et w ithits armature is mo un te d upo n alittle bridge w hich is attached to amaho gany stand similar to that o f the tran smitting in strument .

The actio n of the apparatus is as fo llow s : When an o te or a

w o rd is soun ded into the mouthpie ce o f the tran smitte r,its

membran e vibrates in un ison w ith the so und,and in doing so

carries the soft iro n inducto r attache d to it backw ards and forwardsin presen ce of the e le ctro-magn et, inducing ase ries of magn e toe lectric curren ts in its surroun ding he lix, w hich are transmitted bythe co nducting w ire to the re ce iving in strumen t, and acorre spo nding vibratio n is the re fo re se t up in the thin iro n armature sumcie n tto produce son o ro us vibratio n s by w hich articulated w ords can be

distinctly and clearly recogn ised .

In allprevio us attempts at producing this re sult the vibrationsw ere pro duced by amake -and-break arrangemen t, so that w hilethe numbe r o f vibratio ns pe r se co nd as w e ll as the time measures

w ere co rmctly transmitte d there w as n o variation in the stre ngtho f the curre n t, w hereby the quality o f to n e w as also reco rded . Thisdefect did n o t preven t the transmissio n o f pure musical n o tes

,n o r

eve n the discord produced by amixture of them,but the compli


cated variatio n s o f ton e , of quality, and ofmodulatio n , w hich makeup the human vo ice , required something mo re than ame re iso

chro n ism o f vibratory impulse s.

In Mr. Be ll’s apparatus n o t o n ly are the vibratio n s in the rece iv

ing in strume n t iso chro n ous w ith tho se o f the tran sm ittin g mem

bran e , but they are at the same time similar in quality to the so und

producing them,fo r, the curren ts be ing induced by an in ductor

v ibrating w ith the vo ice , difference s o f amplitude o f vibrationscause differen ce s in strength o f the impulses, and the articulatesound as o faperson speaking is produced at the o the r en d .

Of the capabilities of this ve ry beautiful inve n tio n , w e can n o t givethem be tte r than in the w ords o fan ear w itn ess

,and n o le ss an eu

tho rity than SirWilliam Thomso n , w ho in his Open ing addre ss toSectio n Aat the British Asso ciatio n at Glasgo w thus re fe rred to it :

“In the Canadian Departmen t I heard To be o r n o t to be

there ’

s the rub,’through an e lectric te legraph w ire but

, sco rn ingmo n o syllables, the e lectric articulation ro se to higher flights

,an d

gave me passages taken at random from the New Yo rk n ew spapers‘ S. S. Cox has arrived ’

(I failed to make out the S. S . Cox

the City of Ne w York Senato r Mo rton the Senate has

re so lved to prin t a tho usand extra copie s the Am e rican s inLo ndo n have re so lved to ce lebrate the coming 4th o f July.

’All

this my o w n cars heard, spoke n to me w ith unmistakable distin ctn e ss by the then circular disc armature o f just such an o the r littlee le ctro -magn et as this w hich I ho ld in my hand. The w o rds w eresho uted w ith aclear and lo ud vo ice by my co lleague judge , Profe sso r Watso n , at the far e nd o f the te legraph w ire

,ho lding his

mo uth clo se to astre tched m embran e, such as you se e befo re you

he re,carrying alittle pie ce o f so ft iro n

,w hich w as thus “

made toperfo rm in the n e ighbo urho o d o f an e lectro -magn e t

,in circu it w ith

the lin e , mo tio n s propo rtio nal to the so n o rific mo tio n s o f the air.

This,the greate st by far o fallthe marve ls o f the e le ctric te legraph,

is due to ayo ung coun tryman o f our o w n, Mr. Graham Be ll

,of

Edinburgh and Mo n treal and B o sto n,n o w becoming a naturalised

citize n o f the Un ited State s. Who can but admire the hardiho odo f in ven tio n w hich devised such ve ry slight mean s to realise the


po in ts d at each vibration . This in te rrupts the curren t flo w ingfrom the batterie s 3 as o fte n as the diaphragm vibrate s, an d there

fo re magn e tise s and demagn e tises the e le ctro -magn e t as often .

Hen ce , w hatever n o te be so unded in to the box athe diaphragm aw ill vibrate to that n o te , and the e lectro-magn e t f w illre spo nd an d therefo re repeat that n o te .

F L9 . 1 .

Musical sounds vary in to n e,in in te n sity, and in quality. The

to n e depe nds o n the number o f vibratio n s pe r se co n d o n ly ; thein te n sity o n the amplitude o r exten t o f tho se vibratio n s ; the

quality o n the fo rm o f the w ave s made by the vibratin g particleso fair.

It is eviden t that in Re iss’

s te lepho n e eve rythingat the re ce ivingend remain s the same

,excepting the n umbe r o f vibratio n s

,and

the refo re the so unds emitted by it varied o n ly in to n e, an d w e re

the refo re n o te s and n o thing mo re . The in strumen t remain ed apre tty philo sophical toy and w as o f n o practical value .

Cromw e ll Varley, in 1870, sho w ed ho w so unds could be produced by rapidly charging and discharging aco nde n se r.

ElishaGray,o f Chicago

,in 1873

,succe eded in pro ducing to n es

from the finge rs w hen rubbing adry so n o rous body,such as an

o rdinary tin can,w hilst the in te rmitten t curre n ts sen t by a

vibrating tun ing-fo rk w e re passing thro ugh it ; and by attachingan ele ctro -magn e t to aho llo w so un ding-box, ope n at o n e e nd clo sedat the o ther, he w as able to reproduce the ton e s o f the musicaln o te s tran sm itted. His e le ctro -magn e t had its armature rigidlyfixed to on e po le , and separated from the o ther by aspace o f

33th

THE TELEPHONE . 527

o f an in ch . He called it a reso nato r. The vibratio n s o f thisarmature are imparted to the sounding-boxand become therefo remagn ified. He co n structed akeyboard, o f tw o o ctaves compass

,

w ith ste e l re e ds, each of w hich w as tun ed to its prope r n o te and

main tain ed in vibration by e le ctro -magn e ts. When the key co r

re spo n ding to any n o te w as depre ssed its co rre sponding re ed w asco nn e cte d to lin e , and the proper n umber o f curren ts tran smittedto the distan t station , w here they operated the reso nator and

thus repro duced the n o te . In this w ay tun e s w ere played and thein strume n t became an ele ctric organ . By attaching o rgan -pipe sto his re so nator he magn ified the soun ds and w as able to fillalargehall w ith musicplayed at place s from 90 to 280 mile s aw ay . More

than that he proved the practicability o f transmitting cho rds andcompo site so unds to distan t place s. Gray also inven te d ame thodby w hich the in ten sity o f the n o tes as w e ll as the ir to n es could betran sm itted. Mr. Le o nard Wray also in troduced acapital rece ive r w hich emits the sounds rece ived from adistance by mean sof R e iss

’

s diaphragm.

It remain ed fo r Profe sso r Graham Be ll,o f Bo sto n

, w ho has

be e n w o rking at this que stio n w ith the true spirit o faphilo sophe rsin ce 1872, to make the disco ve ry by w hich to n e

,in ten sity

,and

quality o f so un ds can allbe sen t. He has re nde red it po ssible toreproduce the human vo ice w ith all its mo dulatio n s at distan tpo in ts. I have spo ken w ith ape rso n at various distan ce s up to 32

mile s ; an d throughaboutaquarter o famile I have heard Profe sso rBell breathe , laugh , sn e eze , co ugh , and in fact make any sound thehuman vo ice can produce. Witho ut explain ing the various stage sthrough w hich his apparatus has passed, it w ill be sufficie n t toexplain it in its pre sen t form . Like Re iss, he thro w s adiaphragmin to vibratio n , but Profe sso r Be ll

’s diaphragm isadisc o f thin iro n

,

a, w hich vibrate s in fro n t o faso ft iron co re I) , attached to the poleofaperman e n t bar magn e t N S (se e fig. This co re become s

magn e tised by the influe n ce o f the bar magn e t N S , inducing alla

'

roun d it amagn e tic fie ld, an d attracting the iro n diaphragm to

w ards it. Arou nd this co re is w ound asmall co il c o f No . 38 silkco vered coppe r w ire . On e end o f this w ire is attached to the lin ew ire , the o ther is co n n ecte d to the earth. T he apparatus at each


end is identically similar, so that it become salternately transmitte rand rece iver, first be ing put to the mouth to rece ive so un ds andthe n to the ear to impart them . No w the ope ratio n o f this apparatus depe nds upo n the simple fact that any mo tio n o f the dia

phragm a. alte rs the co nditio n o f the magn e t fie ld surro un ding thecore 6, and any alteratio n o f the magn e t fie ld, that is, e ither itsstre ngthe n ing o r w eaken ing

, mean s the inductio n o f acurren t of

e lectricity in the co il 0. Moreover, the stre ngth of th is inducedcurren t depends upo n the amplitude of the vibratio n , an d its formo n the rate o f vibratio n . The number o f curren ts se n t o f course

I n to

depends upon the number o f vibratio n s o f the diaphragm. No w each

curren t in duced in the co il 0 passe s through the lin e-w ire to the coilc‘,and the n it alte rs the magn e tisatio n o f the core 61

, in creasingo r dimin ishing its attractio n fo r the iro n diaphragm a

l. He nce the

diaphragm a’ is vibrated also , and e very vibratio n o f the diaphragmamust be repeated o n the diaphragm a‘ w ith astre ngth an d formthat must vary exactly to ge ther. He nce , w hate ve r so un d producesthe vibratio n o f ais repeated by a‘, because its vibratio n s are anexact repe titio n o f tho se o fa.

It is quite e vide n t, ho w eve r, that Be ll’

s te lepho n e is limite d in Its

range . The curre n ts ope rating it are ve ry w eak, and it is so sen

sitive to curre n ts that w hen attached to aw ire w hich passe s in then e ighbo urho od o f o the r w ire s it is subje ct to be acte d upo n byevery curre n t that passe s thro ugh any o n e o f tho se w ire s . Hence ,o n abusy lin e , it emits so unds that are ve ry like the patte ring ofhail again st aw indo w ,

and w hich are so lo ud as to o ve rpo w e r the

effects o f the human vo ice .

No w , Mr. T. A. Ediso n,o f Ne w Yo rk, has e n deavoured to

remedy the se defects in Be ll’s by in troducing atran smitter, w hich


in terfe ren ces o fw o rking w ire s w ill seriously re tard the employmento f his apparatus

,but the re is n o doubt that scie n tific in qu iry and

patien t skill w ill rapidly e liminate allpractical defects.To Pro fe sso r Graham Be ll must be acco rded the full cre dit ofbe ing the first to tran smit the human vo ice to distan ce s beyo n d thereach of the ear and the eye by mean s o f e lectric curre n ts.

THE ELECTRICITY OF LEAVES.

At the last me e ting o f the Ro yalSo cie ty Dr. Burdon -San de rsonreadapape r o n the mechan ical e ffects and the e lectricaldisturbanceco n se que n t o n excitatio n o f the leaf o f D io nceamusci p ula. The

m e chan ism by w hich the leaf o f Dio naeaclo se s has already be enstudie d by Mr. Darw in , but the experime n ts n o w made add muchto o ur k no w ledge o f the nature o f the excito -co n tractile pro ce ss inplan ts an d an imals. The first se t o f experimen ts w ere to de term in ethe time that elapse d be tw e en to uching o n e o f the sen sitive hairsan d the first perceptible mo tio n . The to uche s w e re give n atin te rvals o f tw o m in ute s. The first half-do ze n pro duce d n o

m e chan ical e ffe ct. Then 25 succe ssive to uche s produced e ffects

w hich vario usly to o k 7, 5 , and 3 se co nds be fo re they caused actualmo tio n . The 26th to uch pro duced mo tio n in 2 °

se co nds, and atthe 27th the leaf clo sed. It w as fo un d byattaching ao n e -grammew e ight that, w ith each to uch afte r clo sing

,the leaf cle n che d tighte r.

With regard to the e le ctrical con dition o f the leaf it is fo un d theexte rnal surface is po sitive to the in te rnal . The e lectrical disturban ce is strictly limite d to the surface o f the leaf

, and do e s n o texte n d to the pe tio le ; the pe tio le simply se rve s as an

0

o rdinarymo ist co n ducto r. Experime n ts w ere also made to asce rtain the

ce n tre o f greate st e le ctrical in te n sity in the leaf, and table s giving

the re sults o f many experime n ts have be en draw n up. In an imalsit has lo ng be en kn o w n that o n ly the n ervous an d muscu lar tissuesare e lectromo tive , an d it w o uld appear that in plan ts it is the leafalo n e that is e le ctromo tive . It w as found by shifting the n e e dle

THE ELECTRICITY OF LEAVES. 631

po in ts to differe n t parts of the leaf that w he n o ne part w as ex

hansted and w ould produce n o e ffects o the r parts w o uld,thus

in dicating that the excitability o f the plan t is a pro perty possessedinde pe n de ntly by the pro to plasm o f e ve ry ce ll in the excitable area.Expe rime n ts have also be e n made as to the time that e lapse sbe tw e e n to uchin g ahair and the man ifestatio n o f e lectric disturbance

,and it is fo und to be from o n e -sixth to o ne-e ighth o faseco n d.

Similar expe rimen ts o n o ther plan ts are promised.

TALL CHIMNEYS AND ELECTRIC CONDUCTORS.

There are fe w chimn eys w hich have any pe culiar histo ric in te re st,bu t an exceptio n is pre se n ted in o n e built at Glasgo w by Mr .

Joseph To w nse nd, and attached to that gen tleman ’

s chemicalw o rks. This chimn ey is to its n e ighbo urs w hat Mon t Blan c is tothe rest of the Alps— agian tamo ng pigmies. The fo undatio n of

this chimn ey w as laid in March, 1857 , and o n the 6th of Octo be r,185 9

,the coping w as added at the to p, at ahe ight o f 468 fe e t

from the fo undatio n , and 454 fee t from the leve l o f the gro und .

At the fo undatio n the o utside diame te r is 50 fe e t, and at the

surface it has dimin ished to 32 fe et , w hile at the top o f the co pingthe diamete r is 12 fee t 8 in che s. On the 9th o f Septembe r

,1859

,

and w hile the chimn ey w as still unfin ished, and therefo re be fo rethe mo rtar w as dry, asto rm occurred, and re sulted in sw inging thechimn ey ou t of the perpen dicular to the exte n t o f 5 feet at the top.

Thisacciden t. though pe rhaps dire ctly due to the sto rm, had its

origin in an egle ct in the building pro ce ss. Pro pe r allo w ance hadn o t be e n made fo r the co n tractio n o f the mo rtar used in se tting thebricks, and as aco nse que n ce a certain n umbe r o f planks w e re

under agreat pressure , be ingarched in the ce n tre . Sudde nly o n e

o f these at o n e side gave w ay in the o scillatio n caused by thesto rm ,

and w ith the un equal pre ssure the chimn ey w as the n fo rcedfrom the pe rpe ndicular to the exte n t abo ve state d . That theacciden t o ccurre d in this w ay Mr . Jo seph To w nse nd ascertain ed by


perso nal obse rvatio n . For atime some fear w as e n tertain ed that

the w ho le chimn ey w ould come do w n , but o n the 2lst o f the same

mo n th measure s w ere take n to preve n t this, and by the lst of

Octobe r the w ho le w as re stored to the o riginal upright form . Thisw as e ffe cte d by saw ing the chimn ey o n the side n eare st to an

imaginary straight lin e . The fo llo w ing figures give theat w hich cuttings w e re made

(D

mfl

c

fl

t-w

l'"

p—lp—d

H

O

u

n—sDO

N)

449 fe e t.

When the chimn ey w as o n ly tw o years old it w as struck bylightn ing

,and afire en sued , the compo sitio n gas-tubing be ing

me lted at adistan ce o f 100 fe et from the gas me ter, though this

latter w as situated 20 fe e t from the chimn ey. To unde rstan d howthis happe n ed it is n e ce ssary to state afe w additio nal facts. The

chimn ey w as pro vided w ith an e lectric co nductor o n o n e side, and

aco il , w hich un ited w ith the co n ductor n ear the ground, w here

toge the r they w ere bound to an iron rod and passe d thro ugh aw e ll o f w ate r

,situated n ear the side o f the fo undatio n

, 7 feet

square an d 2 fe e t de ep, and the n ce do w n abo ut 8 fe e t in to theearth. No w , in to this w e ll come s the drainage o f the w o rks

, and,further, the discharge pipe from aw ate r-clo se t

, and it w as foundo n inve stigatio n , that, altho ugh the pipe actually dischargin g in tothe w e ll w as o f sto n e w are , ye t, further back, it w as in co nn e ctio n

128 fe e t from the

49 fe e t be lo w 1

22 2

15 3

12 4

19 5

20 6

13 7

20 8

30 9

40 10

40 ll

41 12


Fo r be side s the expo sure o f the w o rkman to the gase s from the

chimn ey,the atmo sphe re is o fte n highly e lectric at that he ight

,and

fre edom from sudde n w in d can n o t be in sure d. The co n structionis n eve rthe le ss approaching completio n , and the w ho le o f it has

be e n do n e by o n e man , Mr. R . Hall .In con cluding this ske tch, w hich w e hope may pro ve o f some

in te re st to man ufacturers w ho have ~tallchimn eys attached to the irw o rks

,w e w ould me re ly po in t o ut that n o t a little succe ss o f the

w orking o f an e lectric co nducto r depe n ds upo n the w ay in w hichit is so ught to distribute the e le ctric curren t o ve r the earth. It is

n o t sufficie n t simply to pass the rod do w n so many fe e t in to theground, but it sho uld te rminate pre ferably in aplate o r shee t ofiro n so as to pre sen t ago od surface fo r diffusio n .

— Iron .

INDEX.

Address, Preside nt’s Inaugural

Automatic Curb-Sender, Thomso n and Je nkin ’s

Adjustme ntsAdvan tage s

Co n tact plateDriving po w er

Con n ection s

Preparato ry Curb

Punche s

Single lever

W o rking prin cipleAutomatic In strume n t, Wh eatsto n e

’s, Descriptio n o f

Ho w to C leanSpare Articles re quired

Aylmer, Jn o . On Lightn ing Co nducto rs employed in FranceAyrto n , W . E., Pro fe ssor, On B ifilar Suspen sio n

On Defe ctive In sulato rsNo tes o n Electro lytic Po larisatio nOn Lightn ing Co nducto rs

Batte ry, On Clamo n d’s Thermo -Electric

Batteries, On the In te rnal R esistance o fBe ll’s Te lepho n e , OnB e ll’s Articulating Te lepho n eB ifilar Suspe n sio n , Quadrant Electrome ter w ithB ro ugh , R . S . On .w inding B o bbin s

Butto n , E. On an o table Thun derstorm

Clamo nd’s Thermo-Electric Battery, On

Measuremen t o f Ten sio n s

R e lative commercial value o f various PilesTable o f co st price

Ele ctro -mo tive force , &c.

Principal me talsand valuesTime o ccupied in arriving at full po tential

Clark, L ., CE . On Clamon d’s Thermo-Electric Battery

Co nductors, Electric, and Tall Chimn eysCo n tributio n s to the Theory of Submergingan dTesting Submarine Te legraphs

VOL. V .

536 INDEX.

Co un cil fo r 1877Co vered W ires, On aNew Fo rm o f Jo in tCurb-Sender, Automatic

Earth Curren tsand the Variatio ns in Terre strial Magn etism, On aNew Mode

o f Studying

Efi ect o f L ight o n th e Electrical Co n ductivity of Silen iumElectric Pe n , Ediso n ’

s, Descriptio n o f.

Po int o f co nn ectio n w ith signalSignals, To w hat, to be applied

Electric Spark Expe rimen t to sh o w the directio n in w hich the , ten ds to

trave lElectricity of Leaves, The

Electro lytic Po larisatio n , No tes o nElectra-Magn e ts, The W ork-Value of, in clo sed in Iro nEle ctrome ter, Quadran t, w ith B ifilar Suspen sio nEw ing, J. A ., On Thomso n

’s Siphon Reco rder

an d Jenkin ’s Curb-Sender

Fahie , J . J On Duplex Te legraphyFle etw o od, C ., On Unde rground Te legraphs, D iscussio n

He ekin , C . ,M .A .

, On the Magn itude o f th e Signals re ce ived thro ugh aSub

marin e Cable w ith vario us co n n e ctio n s at each e n d, an d the be st R e sistan ce

fo r th e R eco rdin g In strume n t

On the Corre ctio n s to be applied to the appare n t R e sistan ceo f the Co nducto r an d In sulato r o f aTe legraph Lin e Whe n de te rmin ed inthe usual w ay by Wh eatsto n e ’

s Bridge

Inaugural Addre ss, Presiden t’s

In sulato rs, P o ro sity o f Defective

On an ew fo rm o f L ightn ing Pro tecto r

Jo in t, On aNe w Fo rm o f, fo r Co vered W ire s

Judd, W . , On the M irro r Galvan ome ter

Langdo n ,W . , On Ele ctric R epeaters

Lightn ing Co nducto rs

Lo ngridge an d B ro o ks, On Submarin e Cable sLo ngridge , J . A . , On Paying—o ut Submarin e Cable sL ightn ing Pro tec

to r, On aNe w Fo rm o f

B ertsch’s

in Use o n Devo n an d Co rn wall RailwaysLo o p Te st, On aNe w Me tho d o f taking the

Madsen , C . L.,Memo ir of Han s Christian (Ersted

538 INDEX.

Siph o n Re co rder, Thomson’s

Mo use M illAdjustment

Pape r R ibbo n , Mo tio n o f

Adjustme n t o fS ignal Co il and Sipho n , Suspensio n o f

Slater, G . B . , Observatio n s o n aThundersto rm 417

Smith , W illo ughby, On New Fo rm o f Jo in t 257

So ft-iro n Co re s, On the use o f, in Thomso n’s Mirror Galvan ome ter 248

Submarin e Cable s, Co n tribution s to th e Theo ry o f Submerging and Te sting o f 42

Submerging Te legraphic Cables, On 42, 269

B est mean s of saving Cable w h en fractured" 291

Co n sideration s in ch ecking paying o ut 287

Degre e o f ten sio n required in paying o ut 278

Deaideratain paying-o ut apparatus 290

Efi ect o f curren tsand waste o f 283

291

Efi ects o f vesse l pitching w hen paying out 289

Mechan ical co n structio n o f cables 297

Observatio ns o n laying 271

Re lative ve locities o f cable and vesse l 278

278

Tall Chimn eysand Electric Co n ducto rs 531

Te legraph Cables, On Submerging 269

262

Un dergroun d— The Lo n do n Stre et System 23

Te legraphy, On Duplex 473

Te lepho ny , On B e ll’s Te leph o n e 500

Tran smissio n qf Musical To n e s by Electricity 503

Te lepho n e , The 525

B e ll’s Articulating 5 19

Terre strial Magn e tism, On aN e w Me tho d o f Studying Earth Curre n ts an d

th e Variatio n s in

Te st, Lo op , On aN ew Metho d o f taking theTh e rmo -Ele ctric Batte ry, Clamo nd’

s, On

Th omso n Sipho n Reco rder

and Jenkin ’s Automatic Curb-Sender

M irror Galvan omete r, On the use o f So ft Iro n Cores in

Thun dersto rm , w hich passed o ve r Clevedo n ,No te s o n

Para, Observatio n s o n

Un dergro un d Te legraphs The Lo n do n Stre e t System

Walker, C . Addre ss

On Electro Magn e ts in clo sed m Iro n

Wheatsto n e , Sir C , Original Pro po sal fo r Anglo-Fren ch CableW heatsto n e

’s Automatic In strumen t, De scriptio n o f

Ho w to cleanL ist o f Spare Articles required

Work-Value ofElectro-Magn ets in clo sed in Iro n

It is particularly requested that any change o f R esidence

o r Addre ss may be commun icated at o nce to the Secretary .

NO T IC E.

LOCAL HONORARY SECRETARIES .

DON Jo si: APAR IC IO,70, dup . Calle dc Pclayo , Madrid

JOHN AYLMER, CivilEngine er,

4, Rue de Naples, Paris

W . E. AYRTON,

Profe ssor o f NaturalPhilo sophy,Imperial Co llege , Toke i, Japan

CHARLES BURTON ,Telegraph Engin e e r,Bucno sAyre s

J . M. COLLETTE

Engin e e r o f the Ne the rlandsTelegraphs, The Hague

E. C . CRACKNELL,Superintenden t Telegraphs,Sydn ey

Le Commandeur E. D’

AMICO,Directo r-Ge n eral o f the ItalianTelegraphs, Rome

FREDERIC DELAROE,Engin e e r o f the Belgian Tele

graphs, Brussels

C . L . MADSEN ,

Great No rthern Telegraph Com

pany, Copenhagen

C . NIELSEN,

Director-Gen eralo f the No rw e

gian Telegraphs, Christian ia

COL . D . G . ROB IN SON, R .E.

Directo r-Gen eral o f the IndianTelegraphs, Calcutta

Dr. WERNER S IEMENS , Be rlin

Do n RAMON VIAL,

Directo r-Ge n eralo f the ChilianTelegraphs, San tiago

G . G . WARD,

Gen . Supe rin tende n t Of th e Direct

Un ited State s Cable Company,New Y ork

SPAIN

FRANCE.

JAPAN.

ARGENTINE REPUBLIC.

The NETHERLANDS .

NEW SOUTH WALES.

ITALY .

BELGIUM .

DENMARK .

NORWAY .

INDIA.

GERMANY .

CHILI .

NORTH AMERICA .

Sarita; at Srlrgqsph (Emitters.

LIST OF MEMBERS,CORRECTED UP TO 3OTH JUNE, 1877 .

HONORARY MEMBERS.

SIB GEORGE B IDDEL AIBY, Royal Observatory, Gre enw ich .

LL .D ., Astronomer R oyal.

GEN . SIR EDWARD SAB INE, R .A.,13, Ash ley Place Westmin ster, S.W .

LL .D .

PROFESSOR W ILHELM WEBER , F.R .S . Go ttingen .

SAMUEL CARTER 3, Clgtor

l:Place , Sussex Square , Hyde

ar C

FRANK IVES SCUDAMORE, C.E. British Post Office , Co nstan tinOple .

TotalNumber ofHon orary Members,

FOREIGN MEMBERS.

AGUAYO, DON WALDO

AHUMADA, Don FRANCISCO

AILHAUD ,M .

AKRELL , Maj orAXEL

ALICE, Don Jo sE

ALTENECK ,F. VON “HEFNER

APARICIO, DON JOSE0

(Hon orary Secretaryfor Spai n .)ABENDBUP , Capt. C . H

Amez, L .

San tiago , Ch ili.Natio nal Te legraph Department,

Ro sario , Argen tin e Republic.

Inspector-Gen eral of the FrenchTe legraphs, Paris.

Royal Sw edish Telegraphs, Sto ckholm

Natio nal Te legraph D epartmen t,JesusMaria, Argen tin e Republic.

94, Markgrafen Strasse , B erlin .

7O, dup. Calle de Pe layo , Madrid.

R oyal Dan ish Engin eers, Copenhagen .

Divisio nal Inspector of NetherlandTe legraphs, Utrecht.

FOREIGN MEMBERS.

BACHELOR , CHARLES

BARON , H.

BATES, D . H.

BAzIRe urRANIAN, Col. CHARLES

BEJAR , Don ALExANDRE, DE

BLAVIER , EDOUARD

BLOKHUIS, G

BONTEMPS, CHARLES

BOYLE, R . K.

B REGUET, ALFRED NIAUDETB REGUET, M . Se n ' .

BR IEVE , C

BROOKS, DAVID

BROWN , A. S .

BURTON , CHARLES,

(Hon orary Se cretaryfor the Argentin e R epublic.)

CALAHAN , E . A .

CAPANENA,PROFESSOR

CAPPANERA, LAMBERTO

CARDARELLI , FEDELI

CARSTENS , P . BOGILAUS

CASTALDI , SILVIO

CHANDLER , ALBERT B .

COLLETTE, J . M .

(H o n orary Secretary fo r taN e therlands

COURTENAY, L. W .

DAKEBS, JAMES Manager, Mon treal Te legraph Company, Mo n treal, Canada.

Men lo Park , New Jersey, U .S.

103, Rue de Gre n e lle , St . Germains,Paris.

Atlan tic and Pacific Te legraph Company, 145, Broadway, New Yo rk.

Government Telegraphs, Teheran ,Persia.

Carthagena, Spain .

103, Rue de Grene lle , St. Germain e,

Te le ah De artmen t, V en lo , Thee t erlan s.

103, R ue de Gre ne lle , St. G ermain s,Paris.

73, B e ekman Stree t, New Yo rk , U .S .

39, Quai de l’Ho rloge , Paris

39, Quai de l’Ho rloge , Paris.

Divisio nal Inspecto r o f Ne th erlandTe legraphs, Ro o sen daal .

22, South Tw en ty-first Stree t, Ph ilade lphia, U.S .

W estern Un ion Te legraph Company,

Telegraph Engin eer, Bueno s Ayres.

New York, U .S .

Directo r-Gen eral o f the B razilianTe legraphs.

Flo ren ce , Italy.

4,Hurst Stre e t, Hern e Hill, S .E .

Royal Dan ish Te legraphs, R o n n e ,B o rn h o lm, Sw eden .

Te legraph Departmen t, Teheran ,

P ersia.

Atlan tic and Pacific Te legraph Company , 145 , B roadw ay, New Yo rk .

Engin e er o f th e Neth erland Te legraphs, The Hague .

45 , Rue de Luxembourg, Paris.

8

HAMILTON, GEORGE A.

HANSEN , EMIL A .

HELLAND, GEORGE T.

HENNINGSEN, JACOR

B EQUET, A.

HOFFM IEB , GUSTAVB OSKIE R , Capt. V .

HUGHES, Pro fesso r, D . E.

ISLA, Don PEDRO I DE LA

JAGER, T. DE

JOHNSON, EDWARD H.

KELLOGG , MILO G

LACOINE, EMILE

LADD , GEORGE J .

LAGARDE , JOSEPH

LAGORE, D o n LUIS

LARKIN , THOMAS J .

LASARD , Dr. ADOLPHE

FOREIGN MEMBERS .

W estern Un io n Te legraph Company197, Broadway, New Yo rk , U .S .

Royal Dan ish Engin eers, Co pen hagen .

Submarine Te legraph Company,

Threadn eedle treet, E.C .

Governmen t Telegraph Department,Barcelona.

Divisional In spector o f NetherlandTe legraphs, Leeuwarden

, TheNetherlands.

New Yo rk, U.S .

220, EastKinzie Street, Ch icago ,U.S .

North Western Te legraph Company,Milwaukee , W isco n sin , U.S .

Atlanticand Pacific Te legraph Com

pany, 145 , Broadway,New York,.S.

Great Northern Telegraph Company,Shanghai .

Great Northern Telegraph Company,Fo o cho w , China.

103, Rue de Grene lle , St. Germains,Paris.

D irecto r o f Telegraphs, Con stan tin o ple .

W estern Un io n Te legraph Compan y ,San Fran cisco

, U .S .

103, Rue de Gren e lle , St. Germains,Paris.

Natio nal Te legraph D epartmen t ,B e llaV ista, Argen tin e R epublic.

Imperial Governmen t Te legraphs,Japan .

German Un io n Te legraph (Company,Wcrder Strasse , B erlin .

FOREIGN MEMBERS .

Lo PEz, Don JUAN

Lo PEz , Do n PEDRO

LORENTZ EN , VALDEMAR

LUDERS , His Exce llency Gen . VON

LUTTEMAN , P. J. H.

MADSEN , C . L . .

(Honorary Secretary for Denmark.)MARTIAL, A. DE SAINT

MAYNARD , G . C.

MERRIHEW , J.

MEYER , B .

MONcEL, Co unt THEODORE DU .

MOOLENAAR , REEDER , H. A.

MOORE, GEORGE W .

MORA, Don ORESTES DE

MORI , Don EMILIO

NAVALLA,W . S .

NIELSEN , C .

(Hon o rary S w r zctm j for No rway .)NIELSEN , C . P .

N IELSEN , F. C . C .

N IELSEN , JULIUS

N IELSON , HUGHN I ERMEYER , J . F.

Natio nal Te legraph Department,B uen o s Ayres, Argentin e Re public.

Natio nal Te legraph Departmen t,R o sario , Argen tin e Republic.

RoyalDan ish Telegraphs,COpenhagen .

Directo r-General o f the ImmrialRussian Te legraphs, St. Pe te rsburg.

Sw edish Government Telegraph Admin istratio n .

16, FrederieksbergAllée , Copenhagen

Secretary o f the Inte rnational Bureau,B em e .

701, Fifte en Street,Washingto n , U.S .

Western Un ion Telegraph Company,Philade lph ia, U.S .

No . 1 , B oulevard St. Den is, Paris.

7, Rue de Hambo urg, Paris.D ivisio nal In spector o f Netherland

Telegraphs, Amaerdam.

Erie , Penn sylvan ia, U.S .

Directo r Of Span ish Telegraphs,Madrid.

Natio nal Te legraph Departmen tBuen o s Ayres, Argentin e R e

public.

Te legraph Department, Teheran ,Persia.

Directo r-Gen eral o f the Norw egianTe legraphs, Christiana.

Great Northern Te legraph Company,Amoy, China.

Great Northern Te legraph Company,Ho ng-Ko ng, China.

Great North ern Te legraph Company,Copenhagen .

Te legraph Engin eer, Toro n to , ,Canada.

Netherlan ds State Te legraph Oflice ,Amsterdam.

10 FOREIGN MEMBERS.

OLORIz, Do n ANTONIO Span ish Government Te legraph s,San tander.

OETON, Ho n . WI LLIAM Presiden t Western Un io n Te legraph

gomglany, 145 , Broadway, N e w

or

PAULSEN, NIELO M .

PELLEGR INO, Commander HERICO

PENTASUGLIA, Commander C .D.

PETERSEN , CARL A .

PETERSEN , JULIUS

PPORDEN ,FREDERICK VON DES

PHILLI PS , W ILLIAM J.

POPE, FRANK L .

PRESCOTT, GEORGE B .

RAN , EDOUARDRAYMOND ,

Mo n s.

RAYNAUD , JULEs

REDONET , Do n JOSEDE .

R ENTZ CH , FRED . JOHN

REPSOLD , J . G

ROUSSEAU, A . J .

RUSSELL , THORWOLD F.

SARGENT, W . D . American District Te legraph Com

pany, Philadelphia, U .S .

SALVATORI , F Italian Telegraphs, Rome .

SCHMITT, J. E. R oyal Dan ish Te legraphs, Nyborg,Denmark.

Great Northern Telegraph Company,Liban Russia.

Italian Te legraphs, Flore nce .

Italian Te legraphs, Florence .

Royal Dan ish Te legraphs, Fredericia,Denmark .

Great Northern Te legraph Company,Calais.

East Indian Te legraphs, Batavia.

Philade lphia, U.S.

Elizabe th , New Jersey, U.S .

Western Un io n Telegraph Company197, Broadway, New Yo rk, U .S .

75 , Rue d’AJ-lon , Brusse ls.

D irecto r o f Stores an d W o rks, 103 ,

Rue de Gre n e lle , St . G ermain s,

Paris.

103, Rue de Gren e lle , St. Ge rmain e ,Paris.

San tander, Spain .

East Indian Te legraphs, Ban jocw argie , Java.

25 , Alsterw eg, St. G e orge , Hamburg.

80, Nevsky, St. Petersburg.

Great N o rthern Te legraph Company ,Nagasaki, Japan .

12 FOREIGN MEMBERS.

V IANISI , Marquis L.

V INCHENT, JULIEN

VOGEL, CARL

Z ETZ SCHE, Professor, Dr. K. E.

Z IGNANO, Don LUIS

Totalnumber of Foreign Members

Messina.In spector

-General o f the B e lgiumPublicW orks, Brusse ls.

94, Markgrafen Strasse , B erlin .

Pro fessorOf Te legraphy,Royal SaxonPolyte chn icon , Dresden .

National Te legraph Departmen t, Frederacio , Argen tin e Republic.

149

MEMBERS.

ABEL , PROFESSOR , F.R .S . R oyal Arse nal, Wo o lw ich .

(P residen t .

ADAMS , Pro fesso rW G .

,

(Membe r of amnml.AHERN , JOHN

A LLEN , JAMES

ANDERSON , R ICHARD , F.C .S .

ANDERSON, S . Capt. R .E.

(M embe r of Co uncil.)ANDREW S, THOMAS

ANDREW S,W . S .

ANSELL , W ILLIAM T.

ARMSTRONG , ADAM

ARMSTRONG , R . Y . , Capt , R .l

(Member of Co un cil.)ASHURST, W . H. Ge neral Po st Office , E .C .

ATKIN SON , Dr. E., F.C .S . Po rte sbury Hill , Camberley, Surrey.

AYLMER , JOHN, C ivil Engin e er 4, Rue de Naples, Paris.

(H o n o rary Secretaryfo r Fran ce . )AYR

'

,I‘

ON W . E . Imperial Co llege , To ke i, Japan .

«Ho n orary Secretanyfo r Japan .

BAILEY, W . H. Albio n W orks, Salfo rd, n ear Manchester.

BARLOW , W ILLIAM HENRY, F.R .S . 2, Old Palace Yard, S .W .

BATEMAN-CHAMPAIN , J . U . ,Majo r 55 , Parliamen t Stree t, S .W .

R .E. We e-P residen t.)BELL , ANDREW

BENNETT, ALFRED ROSLING

B ETTS , A . S .

B ETTS , J . A.

B ETTS , J . F. H.

B IRD ,GEORGE

Phys

‘

i

‘

c

r

alLaborato ry, King’s Co llege

.C .

6 , Dale Stre e t, Lo w er Broughto n

Road, Man cheste r.

Te legraph Superin tenden t, GreatSo uth ern Railw ay, B uen o sAyre s.

R . S . New all and Co ., 130, Strand,W .C .

Jun ior Un ited Service Club, S .W .

Fren ch Atlan tic Te legraph CompanyBrest.

16, Te legraph Stree t, E.C .

66 , Old B road Stre e t, E .C .

R egen ts W o rks, Harro w ly Stre e t,Man chester.

Chatham .

Po stal Te legraphs, G louce ster Road,

10, Palmersto n R oad, Upto n , Essex.

Kurrache e .

Fo o chow , Ch ina.

109, Cann o n Stre et, E.C .

Te legraph Departmen t, Christchurch ,Can terbury, Ne w Zealand.

14 MEMBERS .

B ISHOP, JAMES DRAPERBLANCHFOBD , HUBERT

B LISSETT, T .

B OLTON , FRANK, LT.-COLONEL

(Iloao rary Se cre tary .)BORDEAUX, JOHN Submarin e Te legraph Company,

Dover.

B OTELER , R . Indian Go vernmen t Te legraphs, Caloutta.

BOYLE, R . V ICARS,B RASHER , A .

B RIGGS, JAMES A.

BR IGHT , SIR CHARLES,

BR ISTOW , G . L .

(Ho n o ra?y Solicito r .)BRITTLE

,JOHN R ICHARD

BROADBENT, T . E . , L ieut. , R .E.

B ROOKE , W ILLIAM R .

B ROUGH, R . S .

B ROWN , E . O.

BURKE , E. HAVILAND

BURKE, J . Indian Go vernmen t Te legraphs.

BURY, V isco un t, K.C .M .G. 65 , Princes Gate , W .

CANN ING , Sir SAMUEL , C .E.

CARGILL , W . W .

,

CECIL, Lo rd SACKV ILLE .

CHAMB RE ,ALAN E .

CHARLES , G . G .

CHAUV IN , GEORGE VON

(rllembe r of Co un cil.)CLARK, EDW IN ,

CLARK,LATIMER ,

(Past P reside n t .)COLLETT , R ICHARD

COOKE, SirW ILLIAM FOTHERG ILL

Shanghai.

Direct Un ited States Cable Co . , 116,Palmersto n Buildings, Old B roadStree t, E .C .

Indian Go vernmen t Te legraphs, Calcutta.

4, B road Sanctuary, W e stmin ster,

55 , Parliamen t Stre e t, S .W .

Indian Governmen t Te legraphs, Basse in , B ritish Burmah .

11, De lahay Stree t, W .

1, CopthallBuildin gs, E .C .

12, Queen Ann e’s Gate , W e stmin ster,

S .W .

Calcutta, India.

Indian Governmen t Te legraphs,B ombay.

Indian Go vernmen t Te legraphs, Calcutts , India.

Royal Arse nal, Wo o lw ich , S .E .

7 , Great W incheste r Stre e t Buildings,Old B road Stree t, E .C .

Care o fMessrs.Malco lm,B runle e s,and

Co . , 14, St. Mary Axe , E .C .

Hayes Commo n , Be ckenham , Ken t.

CameraLodge , South N o rw o o d, S .E .

Indian G o vernmen t Te legraphs, Calcutts .

6 , Half Mo o n Stre e t, P iccadilly, W .

6, W e stmin ster Chambers, W est

min ster, S .W .

6, W e stmin ster Chambers, W est

min ster, S .W .

25 , Burghley Road, Highgate R oad,N .W .

Farnham, Surrey.

16 MEMBER S .

FLEMING , J. C .

FLOYD , W ILLIAM HENRY

FORDE, H. C ., M . .I C .E.

FOSTER , A. LE NEVE

FOSTER , PROFESSOR G . C . , F.R .S .

Vi ce-Presiden t.

FRANCE , J. R .

FRANCIS, FRANK RICHARD

FRASI , FREDER ICKFULLER , JOHN

FULLER , JOHN W .

FULLER , THOMAS

FURzE , EDW IN

GALTON , Capt . DOUGLAS , C .D. , F.R .S .

GAVEY. JOHN C .

GERHARDI , CHAR LES A .

G ILBERT, EDWARD

G ILL , W . J Lieut. R E .

GLADSTONE , Dr. JOHN IIALL,GLOVER , T . G . , CO] . R E.

(.llembe r of Co un cil.)GOLDSTONE , CHARLES

GORDON , C . P . B .

GOSSELIN , G . A .

GRAVES , A .

GRAVES , E .

(illembe r of Coun cil.)GRAVES, JAMES

GRAY, MATTHEWGREENER , J . H.

GREENHILL, MATTHEW C .

Superin te nde n t Go vernme n t Telegraphs, Perth ,W estern Australia.

Go vernmen t Te legraphs, Tauranga,Bay o f Plen ty , New Zealan d.

6, Duke Stree t, Ade lphi, W .C .

East Hill , Wan dsw o rth .

12, Hilldrop Road , N .

27, Amherst Road , Hackn ey .

Cro w n Te legraph W o rks Com any,52 and 85 , Hatto n Garden , .C.

65 , B rew er Street, W o o lw ich , S .E .

Ne w castle W harf W o rks, Old Ford

Road, BOW , E .

Care o f Me ssrs . Case an d Lo ndo n sack,1, James Stre e t, Ade lph i, W .C .

B razilian Submarin e Te legraph Co .,

8, Great W in che ster Stre e t, E .C.

B uen o s Ayres.

Chester Stre e t, Gro sven o r P lace , S .W .

Direct Un ited State s Cable Company,Ballin ske lligs.

106, Cann o n Stree t, E .C .

Supe rin tenden t-in -Chie f, the G o vern

men t Te legraphs Of Japan , Yo kohama.

1, Edin burgh Man sio n s, V ictoriaStre et , S .\V .

17, P embridge Square , W .

B urw o od, IIersham, n ear Esher.

Lo ndo n and South W e stern Railw ay,So uthampto n .

Indian G o vernmen t Te legraphs, Calcutta.

Indian Go vernmen t Te legraphs,Co lombo , Ceylo n .

Po rt Darw in , So uth Australia.

Fren ch Atlan tic Te legraph Company,St. Pierre , N e w fo undlan d.

3, Prio ry Stre e t, Micklegate , Yo rk .

Po stal Te legraphs,Gen e ral Po stOffice ,E .C .

Anglo -American Te legraph Com

pany, Valentia, Ire land .

106, Can n o n Stree t, E .C .

14, St. Sw ithin’s Lane , E.C .

Po stal Te legraphs, B elfast.

MEMBER S . 17

GR IFFITH , G . Master o f Natural Science , Harro wScho o l , Harro w .

GR IMSTON , GEORGE SYLVESTER 227, Schadew achten Strasse , Sten dal,Germany.

GROVER , GEORGE E., Capt. R .E. Staff Co llege , Farnborough Road.

GUENzEL, ERNST

GUTTERES, J. Kingsto n , Jamaica.

HALL , W ILLIAM HENRY, Capt.

HALPIN , Capt. ROBERT C .

HANCOCK, WALTER

HARVEY, FRED .

HAWKINS, FREDERICK

HAYNES, FREDERICK T . IAGO

HENEAGE , F. W . , Capt. R .E.

HENLEY W . T.

HIGGINS , FREDERICK

(Associate-Member of Co un cil.)HOCKIN , CHARLES , M .A ., C .E.

(Member of Co un cil.)HOELTzER , C .

HOLMES , NATHANIEL JOHN

HOME, B ., Col. R .E.

HOOPER , J . P .

HOOPER , W ILLIAM

HOUGHTON , E.

HYDE, H., Col. R .E.

IRV INE, A . H. 37, Arunde l Garden s, Kensington ,W .

Messrs. Siemens Te legraph Works,Charlto n .

Go vernmen t Te legraph Departmen tMe lbourn e , Australia.

JAMIESON ,ANDREW ,

Eastern Te legraph Company, Malta.

B

19, Glo ucester R oad, Hyde Park, W .

38, Old Broad Stre e t, E.C .

10, Upper Chadw e ll Stree t, Myddle to nSquare .

Care o f Capt. Davidso n , Cassilla, N0 .

5 , Buen o sAyres.

India Rubber an d Gutta PerchaCompany, Silverto w n .

Great W estern Railway, Taun to n .

Fort Mo nkto n , Go spo rt .

Che sterto n Ho use , Plaisto w , Essex.

Exchange Te legraph Companv 17,Co rnh ill, E .C .

8, Avenue R oad, St. John ’sW o od.

Cambridge House , Old Charlto n V illage , Kent.

7, Great W in chester Street Buildings,Old Broad Stre e t, E .C .

In tel

éigence Departn Ient, War Office ,.W .

The Hut,” Mitcham.

B eechw o o d, Clapham Common .

Lo n don Brighto n and South CoastRailw ay Company, Londo n

B ridge , S .E.

I ndiaOffice , Westmin ster, S.W .

18 MEMBERS .

JRHYLL H., Lieut. R .E.

JENKIN Fle eming, F.R .S . ,M .I .C . .E

JER

EOIS

, Sirw .H., Col.

.B .

JOHN SON , J . THEWLIS

JOHNSON , WALTER C .

JOHNSTON , W . P .

JONES, J . C . D .

JONES, T . J .

JUDD , WALTER ,

KAI SER , E. F. 94, Markgrafen Strasse , B erlin .

KEMPE,H. R . Po stal Te legraphs, Te legraph Street,

(Associate-Member of Council. E.C .

KIESER , W . 112, St. Martin’s Lan e , W .C .

LADD , W .

LAM BERT, FRANK

LAMBERT, M . , Maj o r R .E .

LANCKERT, EDWARD

LANGDON , W ILLIAM

(Acti ng Secre tary .)LANE , J . M .

LAW S , J . C .

LEMON , C .

LE MESUR IER , F. A . , Capt.

LINDEMANN ,ADOLPH

LINDSAY, LORDLOEFFLER , LOUIS

LUKE , S . P . Y .

LUNDY, CHARLES

MACLEA\ ,F. G . Kurrache e .

MAITLAM ) , JAMES M . II . Maj o r R .E. B rompton Barracks, Chatham.

2, Mo rpe th Terrace , V icto riaPark .

3, Great Stuart Stre e t, Edinburgh .

Singapo re .

Bradfo rd Iro n Wo rks, Manchester.

W o o

glands,Lan sdo w n R oad,Charlto n ,.E .

67, Go w er Stree t, W .C .

Eastern Extensio n Te legraph Com

pany, Singapo re .

4, Ge o rge Stre e t, Han over Square ,W .

Eastern Exte nsio n Te legraph Company, Penang.

B eak Street, Regen t Stre et.15 , Great Castle Stre et, Regen t

’s

Circus.

Sho eburyn ess.

Siemen s B ro thers’ Te legraph W o rks,

Ne w Charlto n , S .E .

Po stal Te legraphs, Te legraph Street,E .C .

In dian G o vernmen t Te legraphs,Calcutta.

41, S t. John ’

s Park , Upper Ho llo w ay.

W e llingto n , New Zealand.

Aldersh o t .

Old Charlto n , S .E . , and Scien tific

Club , 7, Saville ROW .

47, Bro ok Stre e t, W .

12,Que e n Ann e ’

s Gate , W e stm in ster,


Direct Un ited States Cable Company,To rbay, No vaSco tia.

:‘l

SCHRAMM , O'

I'ro 12.Queen An e

‘s Gate. Wm inm ,

SCHWENDLER , L . , C .E.

(Membe r ofamn e il. )SCOTT, R . G . Capt . R E .

SCRATCHLEY , P . H .,Lieut.-C ol. RE.

SHEATH, ALFRED

SIEMENS , CARL ,M .I .C.E .

SIEMENS , CHARLES WILLIAM,

FR S . D .C .L . (Past

SIMMONS , S ir J . LINTORN ,Majo r-Gen .

R .E ,K .C .B .

SIVEWRIGHT , JAMES , M .A.

SKINNER . T .

SKINNER ,L ieut. W . M .,R.E.

SMITH ,THEOPHI LUS

R u m Fw d b dmuw xi

“ w as”o n“,War I } ‘

l i'r

M M ‘fi

‘li VII

! ‘34‘

/’1 4

‘h o

w ilder

o w f ol/m” !l/ fh o/ u :

“A M S i n -Ami

w -J ‘ o of a-7 0

w e

p'

l'

‘ ifi é‘ a/ / / t

12,ag n Anne‘

s Gate , Westminster,

12, Que en Anne ’s Gate , Westminster,

SW

Inspecto r-Ge neral o f Fortificatima

War Ofi ce , S.W .

Patti}!

(Te

legraphs, Te legraph Stree t,

3, Ho rbury Terrace , No tting Hill.Portsmouth .

6 , Merrick Square , Borough, S.E.

18, Wharf Road, City Road, N.

G . W . Railway, Paddingt on , W.

315 , Gree n Lane , Birmingham.

Jun io r Un ited Service Club,Waterlo o

Mano n , Hollingw n Park,

Mayo C ollege , Ajuw re , In d ia,

59, Wellingto n “and , b ubble

Boyd W Omar , ”all“ .

42A,W M , I! .W

20 MEMBERS .

PAGE, CHAS . JOHNPARSONS, Lieut. . Col. R .M . , R .E. ,

PELL, BENNETT .

PHILLIPS, SAMUEL E. Jun io r

POPE, J. G .

POSSMANN , J.

POULETT, The EARL

PREECE, JOHN R ICHARD

PREECE, W . H . ,

Vice-P reside n t.)PUNSHON , ROB ERT

RADCLIFFE, ARTHURRADCLIFFE , JAMESRAWSON , HERBERT., Lieut. R .E.

REYNOLDS, CHARLES

RHODES,E . F. , Lieut. R . E.

R ICHARDSON , G .

R IDDALL , EDWARD

ROB INSON , D . , Co .lR UE

(H o n o r-ary Secretaryfo r I nd ia.)

ROG ERS, R . W . S . Lieut. R UN

ROSENBUSCH , EDWARD

SAB INE , ROBERT, C .E.

SACH , IIENRY

SALOMONS, SIR DAVID , Bart , D .A.

SANGER , THOMAS HENRYSAUNDERS , II . C .

SAUTY, C . V . DE

SAWER , R . , C .E.

East Indian Te legraphs, Batavia.

Ordnan ce Survey Ofi ce , So uthampto n .

General Manager Australian 8e Ch inaTe legraph Company, Singapo re .

14, Charlton V illas, Church Lane ,Charlton , S.E.

Indian Governmen t Te legraphs, careo f Messrs. King 85 Co . , 45 , PallMall.

Indo -European Te legraph Departmen t, 28, W estmorland R oad;Westbo urn e Park .

7, Palace Gate ,andHin to n St. Geo rge ,Crew kem e , Somerse t.

Indo-European Go vernmen t Te legraphs, Teheran , Persia.

Go th ic Lo dge , W imbledo n .

Hatherle igh, Ann erley Park, Surrey.

7, Un io n Street, B irmingham .

Great No rthern Railw ay, R e tfo rd.

Fo rt Mo nckton , Go sport.Indian Governmen t Te legraphs , Cal

cutta.

Po rtsmo uth .

In dian Governmen t Te legraph s, Calcutta.

Old Charlto n , Ken t.Directo r-Gen eral o fIndian Te legraphs,

Calcutta.

II .M .S . V ern on ,” Po rtsmo uth .

Mediterran ean Exten sio n Te legraphCompany, Vale tta, Malta.

Gro smon t Ho use , Hampto n R ise .

Great Eastern Railway, Live rpo o l

Stre e t Statio n , E .C .

B ro om Hill, Tunbridge W e lls.

P o stal Te legraphs, Dublin .

Easter nTe legraph Co .,66

, Old B roadStree t. E .C .

Eastern Telegraph Company,G ibraltar,

Po rt Elizabe th, Cape Colo n v.

22 MEMBERS.

TODD , CHARLES, C . M. G.

TODD, K. R . , Lieut. R E.

TREUENFELD , R . VON . FISCHER

TROWER , M . R .

TRUMAN , EDWIN THOMAS(Associate-Member of amnoil.)

TUBE, H. H

TURNER ,H. F., Capt. R E.

TYNDALL, Pro fessor JOHN , LL.D.,

F.R .S .

VARLEY, C . F., 1, GreatW inchester Stree t Buildings,

(Membe r of Coun cil.) Old Broad Street, E.C.

VARLEY, F. H. Mildmay Park W o rks, Stoke New

ingto n , N .

VARLEY, S . A. 66, Roman Road, Ho lloway, N .

WALKER , A . O .

WALKER , C . V .

,F.R .S .

F.M .S . (Past-P reside n t.)WALKER ,

F.. J . DOUGLAS

WALSII , JOHNWALKER , S IDNEY T .

WALTON ,H. I .

WARBURTON ,E . C .

WARD ,G . G .

(Ho n 0 7a7y Sec7 e ta7 7y fm N . Ame 7 ica

WARDEN ,W . M .

WARREN , TIIOS T . P . B RUCE

W EAVER , HENRY

W EB B ,

‘

F . C . ,

W EB B ER , C . EDMOND ,Maj o r R .E .

WHITEHOUSE ,E . O . W ILDEMAN

W IESE , W

Directo r Gen eral So uth Australia;Te legraphs, Ade laide , Australia.

Aldersho t.12, Queen An n e ’

s Gate , W e stminster,

Co nservative Club, St. Jame s Street.23, Old Burlington Street, W .

Indian Government Te legraphs, Indore , Cen tral India.

Postal Te legraphs, Ipsw ich .

Roya‘lvInstitution , Albemarle Street,

Stockto n and Darlingto n Railw ay,Te legraph Departme n t , Darlingto n .

Fern S ide , R ed Hill, Surrey , andScie n tific Club, Saville R o w .

Indo—Euro pean Te legraphs, Sh iraz,Persia.

Po stal Te legraphs, Man cheste r.

18, Ge orge Stre e t, No ttingham.

Te legraph Departme n t,Lan cash ireandYorksh ire Railw ay, Man che ster.

D ire ct Un ited State s Cable Company,16, B road Stre e t, N ew Yo rk.

Broad Stre e t , B irmingham .

4, Lan sdo w n Terrace , Ilfo rd Road,

Essex, E.

1 , Albert Square , Clapham Road,S .W .

57, Maitlan d Park Road, N .W .

Po stal Te legraphs, Mo o rgate Stree tB uildings, E .C .

D o w n Place,Harting, Pe te rsfield .

Indian Go vernmen t Te legraphs, Fredericksw ork, D enmark.

MEMBERS.

W ILLIAMS, W .

W I LSON , W I LLIAM L , F.C .S .

W INTER , G . K .,

W INTER , W ILLIAM HENRY

W RAY, CECILWRAY, LEONARD, Jun ior

TotalNumber ofMe mbers

23

In dian Go vernmen t Te legraphs,Calcutta.

33, Addiso n R oad, No tting Hill.Arco num,

n earMadras.

Po stal Te legraphs, Gen eral Po st

Ofiice .

W o odend House , Walthamsto w .

Woodend House , Walthamstow .

ASSOCIATES.

ADAMS,ALEX. J. S.

ADAMSON , E. W .

AIRD , JOHN , JuniorALDIS , ROB ERT W .

ALDRIDGE, J.

ALLEN , C . E .

ALLEN , J. J .

ALMACH, EDWARD

APPLEGARTH , EDW IN

ARNOLD , GEORGE

ARNOLD ,JOHN

ASCOUGH , T . B .

ASH, W ILLIAM H.

ASHTON ,EDW IN

BADCOCK , JOHN J .

BAGNOLD , ARTHUR II . Lieut. R E .

BAI LEY, JOHNBAILEY, S . S .

BAMB RIDGE, G . H .

BANKER , S . M .

BARRY, J . D .

BARRY, P . F .

BATCHELDER , ROB ERT

BAYLY, B RACKENBURYBAZ ELEY , THOMAS

Po stalTe legraphs,General Po stOfiice .

Submarin e Telegraph Company, Eastdean , Eastbourn e .

B e lvedere Road, Lambe th .

Po stal Te legraphs, Co lchester.

British Te legraph Man nfae tory, 374,Eusto n Road, N .W .

Indo—European Go vernmen t Te legraphs, Bushire .

Indian G o vernmen t Te legraphs, Calcutta.

Faw ley Rectory, n ear Hen ley-ouThames.

116 , Palmersto n Buildings, o n B roadStree t, E .C .

Po stal'

Telegraphs, E.C .

Postal Te legraphs, E.C .

Po stal Te legraphs, Te legraph Stree t,E.C .

Eastern Te legraph Company, 66, OldB road Stree t, E.C .

Po stal Te legraphs; Camden To w n ,N .W .

Te legraph Message Branch , G .P .O.

Aldersho t.

In diaRubber Co . , Silverto w n, E .

Anglo-American Cable Company,Heart ’

8 Co n ten t.

Superin tenden t, D ire ct Un ited StatesCable Company , Lo n do n .

Po stal Te legraphs, E .C .

116, Palmersto n B uildings, Old B roadStree t, E .C .

Brazilian Te legraph Company , St.V in cen t.

88,B o lso ve r Stre e t, N .W .

Go vernmen t Te legraphs, Cape To w n .

Po stal Te legraphs, Cardiff.

26 ASSOCIATES .

BROGDEN , JAMES

BUCKNILL, J. T . , Lieut. R E.

BULL, EDWARD

BULLIVANT, W . M .

BULLOCK, THOMAS A.

BULMER , J. A.

BUTCHER , S .

CARLISLE, HENRY

CARPENTER , JAMES T.

CARPENTER , F. H.

CARR , GEORGE M .

CARSON , J. H.

CASTLE , E .

CAWOOD ,REUBENCHAMBERS, JOHN CHARLESCHEESMAN , H. G .

CLAPPERTON ,GEORGE

CLARKE , STAN LEY

CLEMENT , ADAM F.

CLIFFORD , Pro fe sso rW . B . , M .A.

COLLEY , B ENJAM IN W .

COLLINGS , CHARLES E .

COLLINS , W . C .

COLLIN S , W . II . Ma_10 1 , RHE

COLLMACHE, C . M . P . S .

COMPORT , GEORGE IIENRY

COOK , E . E .

COOKE , CONRAD W .

CORNER , C . R .

Cox,H. J .

CRAMPTON ,T. RUSSELL , M .I .C E .

CRAW LEY,JAM ES

Tea Bank Ho use , Po rthcaw l, n earBridgend, Glamo rgansh ire .

Chatham .

Eastern Te legraph Company , Pe rthcurn o , Penzance .

59, Fe nchurch Street, E.C .

Eastern Te legraph Company, 66, OldBroad Stree t, E.C .

Po stalTe legraphs, Hull.Indo-European Telegraph Depart

ment, Kurrachee .

Eastern Te legraph Company, Suez.

39, Milton Stre et, Dorse t Square .

Western and Brazilian Te legraphCompany, Para.

Po stal Te legraphs, Sunderlan d .

Anglo-American Te legraph Company,Lo ndo n .

4, B rick Co urt; Temple , E .C .

Po stal Te legraphs, Glasgo w , N .B .

Po stal Te legraphs, Sto ckto n -o u-Te e s.

Eastern Te legraph Company, Porthcurn o , Penzan ce .

Direct Un ited State s Cable Compan y ,Rye B each , U .S .

Dire ct Un ited States Cable Company,Ballin ske lligs.

No rth B ritish Railway, Edin burgh .

26 , Co lville R oad, Baysw ater.

Anglo-American Telegraph Company,Bre st.

Po stal Te legraphs, Plymouth .

24, Old Jew ry , E.C .

Chatham .

Anglo -Ame rican Te legraph Com anDuxbury , U .S .

p y

Po stal Te legraphs, No ttingham .

Po stal Te legraphs, Te legraph Stre e t,

57, Lan de r R oad, Clapham R ise , S .W .

3, CopthallChambers, Throgmo rto n

Stre e t.

48 , Arthur Road, Hollo w ay , N .

4 , V icto riaChambers S .W .

42 , Bro ughto n Road, Sto ke N e w ingto n .

ASSOCIATES . 27

CRILLY, JOHN HAMILTON Angl

lg-American Telegraph Company,rest .

CROSS, P . W . Po stal Te legraphs, Cardiff.CROSSLEY, LOUIS J. Mo o rside , Halifax, Yo rksh ire .

CUTTRISS, CHARLES Anglo-American Te legraph Company,Duxbury.

DALLAS, JOHN Geo logical Society,Burlington House ,Piccadilly.

DALLAS, THOMAS E. IndiaRubberW orks, Silverto w n .

DANVERS, F. C . IndiaOfi ce , S.W .

(Auditor)DAVIDS, R . G . B .

DAVIES, DAVID

DAVIES, F.

DAVIES, W ILLIAM HENRY

DE MARSAC , F. R .

DENNETT, W ILLIAM

DICKENSON , SAMUEL S.

DICKENSON , W .

DIESELHORST, W ILHELM

DOHERTY, JOHNDONALD , JOHNDONALDSON , J .

DORMAN ,THOMAS

DOUGLAS, SHOLTO McKENe

DOWNING , W .

DRAPER , GEORGE

DRESSING , CHRISTIAN

DRURY, W ILLIAM , Sen .

DUR BEN , GEORGE

DUCLOY , JACQUES F.

DUFF, B .

Estradade Ferro , Compan triaPaulista, Campestina, Brazil.

The RoyalPo lyte chn ic Institutio n ,

Lo ndon .

Anglo-American Te legraph Company,Valen tin .

Exchange Te legraph Company 17, a

Cornhill, E.C .

Indian Go vernment Telegraphs, Calcutta.

Post Onice Te legraphs, Dover.

D irect Un ited States Cable Company,To rbay, U.S.

Anglo -American Te legraph Company,Hearts Co n ten t.

Messrs. Siemen s Bro thers, Charlto nPier, W o o lw ich .

Po stal Te legraphs, Man chester.

Po stal Te legraphs, Stranraer.

Po stal Te legraphs, R eading.

Po stalTe legraphs, Sto ckto n on-Tees.

Australian and ChinaTe legraph Company, V esuvius, De li, Sumatra.

Te legraph Co n structio n and Maintenan ce Company?Gre enw ich .

Eastern Te legraph Company, 66, OldB road Stre e t, E .C .

Great Northern Telegraph Company,Aberde en , N .B .

61 , South Hill Park, Hampstead.


Submarin e Te legraph Company,Threadn eedle Stree t, E .C .

Go vernme n t Te legraph Departmen t ,Cape o f Go o d Ho pe .

28 ASSOCIATES.

DUNN , ANDREW S Te legraph Departmen t, Caledo n ianRailway Co ., G lasgo w , N .B .

DURNFORD , ARTHUR G . , Majo r, R .E. Aldersho t.DURRAN , W ILLIAM Easte rn Te legraph Company, Alex

andria.

EARLE, EDWARD

EARLE, SAMUEL A .

EB EL , JULIUSEDEN , AUGUSTUSEDWARDS, ERNEST W .

EDWARDS , J . R

EGG INGTON , ALFRED

ELLIOTT, THOMAS

EMMS , E . , Sergt. R .E.

EVANS , FREDERICK E .

RYMERS , F. C .

FAHIE , J . J .

FALCK , A .

PAQUES , JOHN

FAULD ING , ALFRED J .

FIELD , CHAR LES

FIELD , GEOR G E

FIELD ING ,Col. th e Ho n . W .

FI SHER ,FRANK

FI SHER ,HENRY F.

FLEETWOOD , CHARLES THOMAS

FLETCHER , JOHN W ILLIAM

FLETCHER , THOMAS

FOR SHAW , ALFRED C . D irect Un ited State s Cable C ompany ,Live rpo o l .

FORSTER , THOMAS Sparro w Hall, Streatham, Surrey .

Anglo-American Te legraph Company,Brest.

Anglo-American Te legraph Company,St. Pierre , New foun dlan d.

Messrs. Siemens Bro thers, Charlto n .

Po stal Te legraphs, Edinburgh .

23, S outhampto n Buildings, Ho lbo rn .

Po stal Te legraphs, Che ster.

Eastern Te legraph Company, Otran to ,I taly .

Po stal Te legraphs, B ishopstoke ,Han ts.

Ipsw ich .

Po stal Te legraphs, B irmingham.

V in e Co ttage , W o o lw ich .

Indo European Te legraph D epartmen t, Sh iraz, Pe rsia.

Great Northern Te legraph Company,G o th en berg, Sw eden .

Te legraph Departmen t, Te heran ,Persia.

W e st Drayto n .

Hithergre en , Le w isham, S .E .

Po stal Te legraphs, B righ to n .

23, B ro ok Stre e t, W .

W'

e stern an d B razilian Te legraphCompany, R io de Jan e irO.

B ritish In dian Exten sio n Te legraphCompany, Singapo re .

Po st Office Te legraphs, Gen eral Po stOffice , E .C .

Londo n an d N o rth W e stern Railw ay ,Te legraph Departmen t, Cheste r.

so ASSOCIATES .

GRANVILLE,W ILLIAM P .

GRAY, ROBERT K.

GREER , MACGREGOR , Lieut.

GREEN , G . A .

GRIFFITHS, CHARLES

GROVES, W ILLIAM

GURDON , W . B .

HALL , JOHNHALL , WALTER

HAN N INGTON ,FRED . M .

HAMILTON , F. A .

HARB OROW , HENRYHARDEY, ROB ERT J .

HARGRAVE , J . W .

HARR ISON , R . H.

HABWOOD ,FRANCIS

HASSARD ,H . S .

HAYES , W I LLIAM

IIAYNES, J .

IIEAV ISIDE , A . W .

HEAV I SIDE , O .

HENLEY, GEORGEHIB B ERD , CHARLES II .

HI LL,JOSEPH TR IPP

HILL , THOMAS

HI LLIARD , AUGUSTUSHOCKLEY, T . T.

HORNER , ALBERT B .

HOOK , GEORGE W .

HOOKEY, JAMES

HOWARD , COSMO G .

HOWE, J . Pernambuco .

12, Avenue Road, Regen t’s Park ,

St. Jo hn ’s Park, B lackheath , S .E .

Po stal Te legraphs, Walpo le Stre e t,New Cross, S .E.

Anglo-American Te legraph Company,Duxbury, U.S.

Elm Lodge , Che ltenham, G lo ucestershire .

89, B o lsover Stree t, Portland Place .

The Treasury, S.W .

Po stal Te legraphs, Manchester.

10, Lo ve Lan e , Wo od Stree t, E C .

12, Queen An n e ’s Gate , W estmin ster,

S .W .

Anglo-American Te legraph Company,26, Old Broad Stre e t, E.C .

4, Circus Street, Marylebo n e , W .

Governmen t Te legraph Departmen t,Cape o f Go od He pe .

Po stal Te legraphs, Carlisle .

The Grange , Ware , Herts.

Eastern Te legraph Company , L isbo n .

66th R egimen t, Messrs. Cox an d Co .,

Craig’s Court, Lo ndo n .

Direct Un ited States Cable Company,Ballinske lligs.

Po stal Te legraphs, G louceste r.

Po stalTelegraphS ,New castle -Ou3, St. Augustin e

’

s Road, N .W’

.

47, Essex Stre et, Islingto n , N .

Gen e ral Po st Office .

Po stal Te legraphs, Gen eral Po stOffice .

Po stal Te legraphs, Ge n eral Po stOffice .

IndiaRubber Company , Silverto w n .

In do -European Te legraph Departme n t, Kurrach e e .

Un iversity Club, S.W .

21, Trin ity Terrace , Brixto n , S .W .

Po stal Te legraphs, Gen eral P o stOffice , E.C.

4, Chalco t Cre scent, Regen t’s Park

,

ASSOCIATES. 31

HUMB LE , GEORGE Po stal Te legraphs, New castle-o uTyn e .

IIUM PHRI ES, W ILLIAM J. Po stal Te legraphs, Limerick.

HUNTER , J . E . Capt. R N . Un ited Service Club, Pall Mall, S .W .

HURLEY, EDWARD BUTLER Indian Telegraph Departmen t, Colombo , Ceylo n .

INGRAM , J. W .

IRM INGER , FREDERICK

I SHERWOOD , FREDERICK

ISLEY, THOMAS

JAMES , J .

JAMES, J . W .

JAMES , SIDNEY

JEFFERY, JAMES

JENKIN , JOHNJENVEY, HENRY W .

JOB SON , HOWARD C .

JOEL , H . F.

JOHNSON , W ILLIAM

JOHN STONE , THOMAS Y.

JONES , JOHN RYMER

JOSEPH , FRANK S .

KENNEY, F., Sergean t R E.

KERRY , C . H .

KILLINGB ECK, W ILLIAM A.

KING , W . F.

Po stal Telegraphs, Gen eral Po stOffice .

Great No rthern Te legraph Company,Ho ng Ko ng, Ch ina.

Po stal(

Te

legraphs, Te legraph Stre e t,

E.

Po stal Te legraphs, No rw ich .

Anglo -American Te legraph Company,Lo n do n .

Anglo -American Te legraph Company,Hearts Co n ten t.

Po stal Te legraphs, Gen eral Po stOffice , E.C.

The D irect Span ish Te legraph Company, The L izard, Co rn wall.

Po stal Te legraphs, Newark , No tts.

Go vernmen t Te legraph Departmen t,M e lbo urn e , Australia.

Dudley .

44, Lavender Gro ve , Dalsto n , E .

Po stal Te legraphs, Le eds.

Persian Gulf Te legraphs,Fao Statio n .

52, Co rn wall R oad, W e stbo urn e Park ,W

13, Clarew ood Terrace , Brixton , S .W .

Po stal Telegraphs, Walpo le Street,New Cross, S .E.

Postal Te legraphs, Bristo l ..7 W . T . Hen ley’

s Te legraph Wo rks,No rth W oo lw ich .

Western and Brazilian Te legraphCompany, R io de Jane iro .

32 ASSOCIATES.

KI NG SFORD , H Enderby’s Wharf, Green w ich , S .E .

KIR BY, GEORGE J . Cape Te legraphs, Po rt Elizabe th .

KN IGHT, JOHN HENRY Po stal Telegraphs, Do ncaster.

LAISTER , JAMES

LANGFORD , H . S.

LAUR IE, E . H.

LAVENDER , JOHNLAW SON , ED . G .

LEA, JOHN

LEE , ROBERT B .

LEONARD , W .

LESSELS , DAVID

LEW IS , R . J .

LLOYD , Lieut. NESHAH

LLOYD , WILLIAM

LOGAN ,JAMES K.

LONDON ,ROBERT

LOWE , THOMAS

LUCAS , F. R .

LYNE, CHAR LES

MACGREGOR ,J. COLLINGS , Lieut. R E .

MACLACHLAN , J . M .

MCDONALD , JAMES R .

MCGAURAN , D . J .

MCKINNEY, ALEXANDERMCLEAN , JAM ES .

MAIN ,DAVID

Po stal Te legraphs, Te legraph Stree t,E .C .

Anglo-American Te legraph Company,Valen tia.

Po stal Te legraphs, Te legraph Street.Fairy Lane , Manchester.

En trada du Cidade , 3, Fun chal,Made ira.

Care o f Mr. Hatcher, No rth CampStation , Lo ndo n and South

W estern Railway, Aldersho t.

South Easte rn Railway Te legraphs,Lo ndo n Bridge .

Po stal Te legraphs, Edinburgh .

Gen eral Po st Office , E.C .

The Jun ior Army and Navy Club,Grafto n Stree t.

Whitehall Club, Parliame n t Street,S .W . 85 19, Fin chley R oad, N .W .

In spe ctor o f Te legraphs, Dun edin ,N e w Zealan d.

84, Tyrw h itt R oad, Le w isham HighRoad, Ne w Cro ss, S .E .

8, GreatW in chester Stre e t Buildings,

3, Glen Mo hr Terrace , Hyde Vale ,Gre e n w ich .

Te legraph Departmen t, Teheran ,Persia.

Aldersho t.Po stal Te legraphs, Ge n eral Po st

Office, E .C .

The Po st Office , She ern e ss .

Manager Te legraph Office , Albury,New South Wale s.

Po stal Te legraphs, Man che ster.

2, Ovingto n Square , S .\V.

Direct Un ited State s Cable Company,Ballinske lligs.

OAKBHOT, A.

OATWAY , ARTHUR

0 0 0 , F. W ILLIAM

O'

HAIRE, J . M .

ASSOCIATES .

Indo -European Go vernmen t Tele

graph , Jask.

Eastern Te legraph Company , Aden .

b ew castle—o u-fi ne .

PostalTe legraphs, Lancaster

OLDEESHAw , J Sergean t B .E .

PAGE, ALFRED S .

PAGE , CHARLES J.

PARKER , J. E.

PARMITER , ALBERT

PAESONE, E . W .

PARSONS, The Ho n . R ICHARD

PARTRIDGE , G . NOB LE

PATER SON , EDWARD J .

PATTEN , FREDERICK A .

PAYN , JOHN J.

PAYTER , J. W .

PERRY, F.

PETERS , ALFR ED

PETERS EN , K.

PETTERSON , OSCAR F.

PHI LLIPS , W . R .

IndiaRubber Co ., Silvertow n .

Company, Bahia, B razil.

PHILLI PS , J . C . ,Qt-Maste r Sergt.PHILPOTT , JAMES J.

PIN CHIN , W ILLIAM HENRY

Po stal Te legraphs, Gen eral Post

Ofi ce , E.C .

ll, Barclay Terrace , Barclay Road,Leyto nstoue , Essex.

Go vernme n t Te legraphs, Cape o f

Go o d Hope .

Ipsw ich .

Po stal Te legraphs, Reading.

175 , Ade laide R oad , N .W .

10, Co nnaught Place , W .

Po stal Te legraphs, Exe ter.

Bedfo rd Co urt, Coven t Garden .

Indo -European Go vernme n t Te legraphs, Kurrachee .

6 , Rue Pavé D’Amo ur

, Marse illes.

Te legraph Departme n t , Me lbo urne ,V icto ria.

Anglo-American Te legraph Company,Hearts Co n te n t.

W estern an d Brazilian Te legraphCompany, Bah ia.

German Un io n Te legraph Com any,4,Werder Strasse , Be rlin .

p

Direct Un ite d State s Cable Company,To rbay, U.S.

Paumbaum, India.

Po rtsmo uth .

Po stal; CTelegraphs, Sto ck Exchange ,Postal Te legraphs, Exe ter.

ASSOCIATES . 35

POMEROY, HENRYPORTELLI , ROB ERT

PRICE , H. P . B .

PROB ERT , J.

PUGET, Lieut.-Col. GRANVILLE W .

QUILLEY, HENRY Ge n eralPo st Office.

RAMSAY, JOHN , Capt. R .E. Schoo l of M ilitary Engin eering,Chatham.

RAPE, L . W . Angig-American Te legraph Company,re st.

REID , FRANK Po stal Te legraphs, New castle-ou

REYNELL , C . H.

R ICH , H. R .

R I CHARDS, A . , Sergean t R.E.

R ICHARDSON , H.

B IEMENSCHNEIDER , FREDK . W . C.

R ISCH , GUSTAV

R ITso , F. C . G

ROBERTS, MARTIN F., F.C .S.

ROBERTSON , J.

ROB ERTSON , F. L .

ROLLS, EDWARD T.

ROSS , JOHN , Quarte rmaster-Sergt. R .E

ROSS, Walte r O.

ROSSE , LEW IS W .

ROWE, THOMAS

RUSHTON , W ILLIAM S.

RUSSELL, FRANK

SALE, M . T., Capt.R.E.

Postal Telegraphs, Ath lon e .

Eastern Te legraph Company Malta.

Eastern Telegraph Company, Mar

‘

se illes.

Po stal Telegragzhs, Mo orgate Stree t

Buildings, .C .

34th Regimen t, Carlisle .

Made ira.

Indian Go vernmen t Te legraphs, Caloutta.

Te legraph Service , South Camp ,Aldersh o t.

Po stalTe legraphs, Douglas, Isle ofMan .

Great North e rn Telegraph Co mpany,7, GreatW incheste r Stre et Buildings, E.C.

6, B righto n V illas, Cranfield R oad ,B ro ckley.

7 , Lo thbury, E.C .

Po stal Te legraphs, Gloucester Road,N .W .

Po stal Te legraphs, Bristo l.W est Coast o f AmericaTe legraph

Company, 98, Can on Street,E.C .

L . and S . W . Railway, Exeter.

Chatham.

Anglo -American Te legraph Com anSt. Pierre , New foundland.

p y,

Anglo-American Te legraph Company,Brest.

Po stal Te legraphs,Manchester.

Gen eralPost Office , E.C .

Wo odfield Road,Harro w Road , N.

36

SAUNDERSON , R . L .

SAx, JULIUSSCHAEFEB , LOUISSCHINDLER , ARTHUR H.

SCOTLAND, JAMES

SHAW , Captain W .

SHEPHERD , F.

SIEMENS , ALEXANDER

SIMMONS , CHARLES J.

SIMPSON , GEORGE

SLATER , W ILLIAM

SMALLP IECE, W ILLIAM D .

SMITH ,B ENJAM IN

SMITH , JOSEPH H.

SM ITH , A. TOULMINSMYTHE , JOHNSPAGNOLETTI , HYLTONSPARR OW , W .

SPRATT , G . O.

SQUIRES , FREDERICK

SQUIRES , GEORGE

STACEY, CHARLESSTACEY, GEORGE B .

STARKE ,HEN RY

STEET , S . G . ,

STELGES , J .

STERNE , LOUI S

STEVENS , FREDERICK P .

STEVEN S, HENRYSTEVENSON ,

ED . ALF.

STEVENSON , GEORGE

STEWART,D

STOKES , CHAR LES S .

STOKES , HENRY L . S .

ASSOCIATES.

Anglo-American Te legraph CompanyDuxbury, U . S .

108, Great Russell Stre et, W .C .

Te legraph Departmen t, Teheran ,Persia.

Anglo-American Telegraph Company,St. Pie rre .

102nd Fusiliers, Garriso n Instructor,Aldersho t.

Po stal Te legraphs, Brighto n .

12, Que e n Ann e ’

s Gate , W estmin ster.

106,W eddingto n R oad,Ken tish :l‘

o vrn .

Indian Go vernmen t Te legraphs,Man nar, Ceylo n .

W e ste rn and Brazilian Te legraphCompany, Para, Brazil .

Warren Ho use , Basingstoke , Han ts.

Eastern Te legraph Compan y, Malta.

Post Office , Se lby .

Se lborn e Chambers, Chance ry Lan e .

Valen tia, Ire land.

4, Circus Stree t, Marylebo n e ,W .

Putn ey.

Eastern Te legraph Company, Fo rt]!curn o , Penzan ce .

Anglo-American Te legraph Company,Bre st.

Anglo -American Te legraph Company ,B re st .

Eastern Te legraph Compan y , Aden .

Eastern Te legraph Compan y , B ombay.

Go vernme n t Te legraph D epartmen t,B risban e ,Queen slan d .

130, King He n ry’s R oad, Hampstead.

So uth Easte rn Railw ay Te legraphW o rks, Tunbridge .

9, V icto ria Chambers, W e stmin ster,S .W .



Te legraph Co n structio n an d Maintenan ce Company , En derby

’s

W harf, East Gre en w ich , S .E .

Eastern Te legraph C ompany, Alexan dria, Egypt .

Po stal Telegraphs, G lasgo w .

7 , No rth Terrace , B rompto n , S .W .

7 , No rth Terrace , Alexan de r Square ,S .W .

88 ASSOCIATES .

TUH 'IEM ) , T. S. 16, AngleseaRoad, W o olw ich.

TUNRRIDGE , W . T.

Stafi ord.

TURNER, W ., Sergt.-Major R.E.

UREN , JOHN GEORGE Penzance .

VENNDT, C . F.

VERNEY, Captain R N . Rh ianva, Bangor, North Wales.VYLE, SAMUEL Po stal Te legraphs, Glasgo w .

WALKER, W ILLIAM K. Sealdah Statio n , Calcutta, E. B . Railw ay, India.

WALPOLE, W ILLIAM BOWMAN 75 , Patshull Road, Ken tish To w n ,

WALTON , JOHNWARD, H. R . P .

WARNER , R . A.

WARREN W ILLIAM

WATERS , HERBERT M .

WATKIN , Capt. R .A .

WATSON , C . M . , Lie ut. R .E .

WATT , GEORGE W . M .

W EATHERALL , T . E .

W EB B,E. M .

WERB ER , T . B .

W EB STER , J . K .

W EEDON ,E.

W ELLS , W . LEW IS

W ERDERMANN , R ICHARDWEST, GEORGE

WHITE , F. H.

WHITMORE, MORTIMER , Lieut. R .E.

Po stal Te legraphs, B irmingham .

1, Basingbo urn e V illas, Albio n R oad ,Tunbridge W e lls.

Cdssilla, No . 777, Buen os Ayre s.

Ge o rge To w n , Tasman ia.

9, Park Terrace , Gre en w ich , S .E .

Sho eburyne ss.

War Oflice , W h ite hall .108, Ball’s Po nd Road, N .

Te legraph Co nstructio n and Maintenance Company, Gre en w ich .

Te legraph W o rks, Silverto w n .

Te legraph Departmen t, Great W e stern Railw ay Company, Plymo uth .

Anglo -American Te legraph Compan y ,B re st.

Anglo -American Te legraph Co mpany ,Hearts Co n ten t.

Submarin e Cable s Trust, 66 , OldB road Stree t, E .C .

4,Prince’s S tree t, Stamfo rd Stre e t, S .E

Easte rn Te legraph Company, Alexandria.

Anglo-American Te legraph Company ,St. Pierre .

Po stal(

Te

legraphs, Te legraph Stre e t,

E.

W IGAN , GORDON

W ILDE, EDW IN

W ILKINSON ,HENRY D.

W ILLIAMS; A . G.

W ILLIAMS , R . PRICE

W ILLMOT, JOSEPH

W ILMOT.T. J .

W INTER , CHARLES E.

WOOD , MAJOR ALEXANDER

W OOD , CHARLES BARKER

WOODCOCK, W .

W OOLLEN , C . H.

W RAY, LEONARD

YEATES, HORATIO

ASSOCIATES .

33, King Stree t, Coven t Garden .

t alNumber of Associates

39

2, Brick Court, Temple, E.C.

Po stal Te legraphs, Leeds.

Eastern Exten sio n Te legraph Com

Pally. Singapo reAnglo-American Te legraph Company,

Hearts Con ten t.Greaévg

're orge Stree t, We stminster.

Postal Te legraphs Gen eral Post

Oflice , E.C.

Direct Un ite d States Cable Company,Rye Beach , U.S .

5A, Ladbroke Gro ve , No tting Hill,W .

Abbey W o od, Ken t.

Superin tenden t Direct Un ited State sCable Company, Chester.

Anglo American Teh graph CompanyHearts Co n te n t .

Po stal Te legraphs, Exeter.

Wo odend House , Walthamstow .

GATEHOUSE, THOMAS 874, Euston Road, N.W .

WALROND ,THEO. C. T. 5 , Netherw o od Road, W e st Kensin g

WARREN . J. D 19, Pelham Street, South Kensington .

TotalNumber of Stude n ts

TOTAL NUMBER OF MEMBERS .

Journal of the Society of Telegraph Engineers - Forgotten Books

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