To Prove That I Can Fit - World Radio History

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09164/C' Me 20 likektiTo Prove That I Can FitYou for $3,500 to $10,000ELECTRICAL JOBS ---

A14,71earlifF

S. V. SMITH

AmarinInYour

Chief Engineer Smith of the famous S. & H. ElectricalWorks, Chicago, is the man rt the left. He is the inven-tor of the wonderful new way of training in actual shoptype electricity, so that you can become an electrical ex-pert in a very short time. By this remarkable new sys-tem Mr. Smith has trained such capable men that hehas been able to place them easily with some of the big-gest concerns in the country. His personal instructionis now within your reach.

ICAN train you in amazinglyshort time to be an electrical ex-pert commanding $3,000 to $10,-

000 a year and up. I say this to youwithout a single reservation, be-cause I have trained hundreds ofmen who now hold big money posi-tions in the electrical world. S & Hmen are in constant demand in thebig electrical shops, everywhere.Many had never gone beyond theeighth grade in school-and yet theyhave stepped into big pay and inde-pendence.

When I discovered this newsimple easy way to carry practicalshop type electrical training to youin your home, I knew I had at lastsolved the one big difficulty of teach-ing men electricity outside of col-lege. And electrical men everywherequickly recognized this. They havehailed my method as the one, sureway of training for the thousandsof big money jobs that await theelectrical expert in this fast grow-ing field. Since making my discov-ery I have turned out hundreds ofmen who are succeeding. In allbranches of big money electricalwork they are proving that the S.& H. shop type training is the great-est system ever devised as a quick,easy way to the best jobs in elec-tricity. You can get S. & H. actual

READ THESE"You will remember that before Mr.Unholz and I took your course of train-ing we were doing common labor. Tojump from this to a prosperous busi-ness of your own Is some jump, butthanks to your wonderful training we'vedone It."

D. Farina, U. & F. Electrical Co."Alhough I have only finished 20 les-sons of your training I have received apromotion and am getting a third moresalary, I am grateful to you."

Anthony Der:an:tar.

pekainhigalbum- META"

shop type practice nowhere else. Itis fully protected by U. S. copyright.

All Branches of ElectricityNo matter what branch of electri-

city you want to learn my traininggives it to you. In a few months Imake you a thorough, competentelectrical technician, with the titleE. T. I train you so that when youare graduated there is no phase ofelectrical work you are not familiarwith-and know a lot more aboutthan the other fellow. My trainingcovers every type of work in elec-tricity.

Men Are NeededDo you know that more than half

the business of the United States iselectrical in nature? This greatfield pays big money and is alivewith countless opportunities. Everyday we have the opportunity to placemen in the better jobs. When youenter the profession you can't affordto be without the prestige and back-ing of the S. & H. Electrical Works.

Free OutfitIf you will mail coupon at once

you will be entitled to my remark-able offer of a complete outfit ofelectrical apparatus, instruments

and appliances for experimental andpractical home shop work. Just asthe famous EMPLOYMENT SERV-ICE and UNLIMITED ADVISORYSERVICE of the S. & H. ElectricalWorks is without cost so is thisCOMPLETE OUTFIT, ABSO-LUTELY FREE to my students-but for a short time only. And eventhat isn't all. I have yet anotherremarkable offer, but haven't spaceto tell it here. You must act ATONCE. Send coupon right now.

S. V. SMITH

S. & H. ElectricalWorks

Dept. A-21422 W. Monroe

StreetChicago, Ill.


Science and Invention for January, 1924 841

Mea like you are needed right now to fill big -paying jobs in the electrical field.There never was a time when opportunities for money -making were as good as theyare now. Good jobs are open everywhere to men who know "what's what." Elec-trical Experts earn from $12 to $30 a day. Even the ordinary electricians get top-notch pay. Why don'tyou get in on this and get a real man's size job now? With my simplified Electrical Course I can quicklyfit you to hold one. Read W. E. Pence's letter below. This is only one of thousands of suchletters I have received.

You Can Be a Big Money MakerI have trained over 20,000 men in electricity-thousands of successful men all overthe world attribute their success to my training. I can make you successful too. Infact I will guarantee your success. If you will follow my home study course you can become an expert, draw-ing a fat salary, in the same time it takes you to get a little raise in the work you are doing now.

lumpsr 125A Month to

$750 Ova nedr

READthe Story of

W. E. Pence

W. E. Pencein his working togs

Age or Lack of Education No HandicapNo matter how old or how young you are, or what education you have, there is a realfuture for you in electricity. If you can read and write I can put you on the road tosuccess. I can help you to a position that will make people admire you and look up to you.

Cash In onYour SpareTimeUse your spare time to get a better job. Mostof us have enough spare time every day to sella little at about $10.00 an hour. Sell some to

yourself at this price. Watch how quickyou will earn the money back if youput the time into study.

Electrical WorkingOutfit Free

Every man who enrolls formy electrical course getsa big outfit of tools, ma-terial and instruments free.This includes an electricmotor and other thingsnot usually found in a be-ginners outfit. These arethe same tools and thesame material you will uselater in your work. Every-thing practical and goodright from the start.

Chehalis, Wash.,Mr Cooke:-

When I enrolled with you less titan a yearago I was a common mechanic earning $25to $30 a week. Today I am an "Electrical Ex-pert" with a business of my own that gives mea clear profit of over $750 a month.

I have more work than I can do. The peoplearound Chehalis come to me to fix their start-ers, generators and ignition troubles becausethey know that I know how to do it right.

My success, I owe to you, Mr. Cooke. Thethorough practical training which you gave methrough your Easily -learned Home StudyCoursein Electricity has made me an independent,highly respected business man in this com-munity. Sincerely yours, W. E. Pence.

L. L. COOKE, ChiefCHICAGO ENGINEERING / part.

WORKS, Dept. 21 Name

2150 Lawrence Ave., Chicago Address

I Guarantee YourComplete Satisfaction

I am so sure I can make a big pay electricalexpert out of you that I guarantee your suc-cess. I agree under bond to return everycent you pay me for tuition when you havefinished the course, if you are not satisfiedthat it is the best investment you have evermade. If you don't make good, this milliondollar institution will.

Act Right Now ILet me send you my big free book /giving details of the opportunitieselectricity offers you and a sam-ple lesson also free. Mail thecoupon and get this at once. jLearn how other men "got -vthemselves ready to hold L. L. Cookegood paying jobs" and Chief Engineer, Chicagohow I can help you do Engineering Works,the same. This is your Dept.21 2150 Lawrence Ave.,big chance-take it. 4/ Chicago, Ill.

Dear Sir: Send at once Sample Les-sons, your Big Book, and full particulars

Engineer of your Free Outfit and Home Study Course-all fully prepaid without obligation on my


IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIa

(.4

Vol. XI.Whole No. 129

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demFORMERLY

ELECTRICAL EXPERIMENTER

Lon January, 1924No. 9

itY11.1101.1111.111111111111111114111111111111111111111111111,

PUBLICATION OFFICE: EDITORIAL & GENERAL OFFICES:542 Jamaica Ave., Jamaica. N.Y. 53 Park Place. New York City

Published by Experimenter Publishing Company, Inc. (H. Gernsback. Pres.: S. Gernsback. Treas.; R. W. DeMott. SWF/.Publishers of SCIENCE AND INVENTION. RADIO NEWS, and PRACTICAL ELECTRICS

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17 Tabile off' Contents for janualry

SOLAR ECLIPSE PHOTOSBy W. E. Burton

COKE AND OIL AS COAL SUBSTITUTESTURBINE -LIKE MACHINE FOR TIDE POWERAUTOMOTIVE IMPROVEMENTS OF THE YEARMAKING BUTTERFLY TRAYS

By Dr. Ernest BadeRADIO POWER ASSURED (Cover Article)

By H. GernsbackFIRST PRIZE WINNERS IN $1,000.00 AWARD FOR

PICTURESTHE AIRPLANE OF THE FUTURE

By H. Winfield Secor.THE MAN ON THE METEOR

By Ray CummingsDR. HACKENSAW'S SECRETS-No. 25-THE SF,

CRET OF THE SUBMARINE CITYBy Clement Fezandie

ZEV-PAPYRUS RACE, CAMERA WARBy \V. B. Arvin

"SURE THINGS" AT THE COUNTY FAIRBy W. C. Kelly

POPULAR SCIENTIFIC ARTICLES PRIZE CONTESTSEDITOR I A I, 849 FIRST AWARDS IN $12.000.00 CONTEST FOR PICGLASS ENCLOSED CITIES OF TO -MORROW 850 TURES 856MOVIES MANUFACTURE OWN LIGHTNING 851 PRIZE AWARDS IN "TOY" CONTEST 873By Phil Gersdorf. CIGAR BOX CONTEST 876BLACK LIGHTNING 851 HOW -TO -MAKE -IT DEPARTMENT-$30.00 IN PRIZES

By T. L. Walker MONTHLY 887851 SCIENTIFIC HUMOR-PRIZES FOR BEST JOKES 900

STEAM DRIVEN AIRPLANEBy Dr. Armin Demuth

"DAYLIGHT" FOR THE STAGEBy A. P. Peek

ENGINEER PREDICTS RAIL FUTUREMILLION TON METEORITE FOUNDSMALL TURBINE DRIVES HUGE. GENERATOR

By Dr. Armin DemuthGIGANTIC ARIZONA CAVERN

By John W. WellsTHE CHEMISTRY OF BREAD MAKING

By lsmar Ginsberg, B.Sc., Chem. EngCHART OF THE DEVELOPMENT OF MAN

By Dr. 0. HauserHUGE WIND POWER SYSTEM

By Raymond Francis YatesA MILLION VOLTS UNDER CONTROL!REVERSIBLE TURBINEPARLOR, BEDROOM AND KITCHENETTEHORIZONTAL INDICATOR FOR PLANES

By Stanley Y. BeachMAGIC FOR EVERYBODY-NO. 10 OF A SERIES

By Prof. Joseph DunningrrTHE HEAVENS IN JANUARYBy Isabel M. Lewis, M.A., of the U. S. Naval ObservatoryMEASURING THE STARS' HEAT

By Edison Pettit, Astronomer, of the Mt. WilsonObservatory.

CAN YOU ANSWER THESE PROBLEMS?.By Ernest K. Chapin

SCIENTIFIC MISCONCEPTIONSBy Raymond B. Wailes

852852853854

855

AUTOMOBILESAUTOMOTIVE IMPROVEMENTS OF THEDEMONSTRATION CAR "CUT IN HALF"RADIO POWER FOR AUTOS ASSURED

By H. Gernsback.ELECTRICITY

ELECTRICITY FROM THE TIDES856 ELECTRIFIED RAILROADS OF TO -MORROW857 SMALL TURBINE DRIVES HUGE GENERATOR

HUGE WIND POWER SYSTEM DEVELOPS ELEC-858 TRICITY

A MILLION VOLTS UNDER CONTROI 'RADIO ARTICLES

HOW. TRANS -ATLANTIC RADIO MESSAGES ARETRANSMITTED AND RECEIVED 888

RECENT ADVANCES IN RADIO APPARATUS -.889-890RADIO MAKES TRANSOCEANIC CIRCLE 891LATEST DESIGNS IN RADIO CABINETS 891SENDING PHOTOS BY RADIO 892THE BIOGRAPHY OF A VACUUM TUBE 893

865 By Jack KayUNTUNED PRIMARY RECEIVER 895

860 By W. L. Pearce867 RADIO FOR THE BEGINNER-NO. 23-INDUC-867 TANCE 896

By Armstrong Perry868 RADIO ORACLE 897.898

RADIO WRINKLES-Edited by A. P. Peck 931

'CONSTRUCTOR ARTICLESGHOST SPECTACLE FOR Ni.vrEult STAGESTAGE EFFECTS FOR NI I I ATUR E THEATRE

By Dr. Ernest BadeSTEREOSCOPIC DRAWING METHOD

872 By Ernest K. Chapin874 HOME-MADE LABORATORY FOCI PM ENT875 By Chas. D. Tenney875 CHEMISTRY ARTICLES

860

862

863

864

YEAR.. 853853855

869

870

871

THE CHEMISTRY OF BREAD MAKING877 By Ismar Ginsberg, B.Sc., Chem. EngHOME-MADE CHEMICAL LABORATORY EQUIP -878 MENTWRINKLES, RECIPES & FORMULAS-Edited by S879 Gernsback

852866867

871872

882883

88"

884

869

884

886ASTRONOMY ARTICLES

880 SOLAR ECLIPSE PHOTOS 851MILLION TON METEORITE FOUND 867881 THE HEAVENS IN JANUARY 878MEASURING THE STARS' HEAT

110W TO SUBSCRIBE FOR "SCIENCE AND INVENTION." Send yourliaise, address and remittance to Experimenter Publishing Co., 53 ParkPlace. New York. Mention the name of the magazine you are ordering.We also publish RADIO NEWS and PRACTICAL ELECTRICS.RATES AND TERMS. The subscription rate for SCIENCE AND IN-VENTION is 82.50 per year. (12 numbers.) When remitting do soby check, money order or registered letter, if cash is enclosed. Avoidsending cash through the mail if possible. Subscriptions for less thanone year are not accepted. Subscriptions may be made in combinationwith RADIO NEWS or PRACTICAL ELECTRICS with considerable sav-ing. Send postal for special rates. Subscriptions start with the currentissue. unless otherwise ordered.I'OSTAGE. We. prepay postage in all parta of the United States, Men -

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cannot be returned unless full postage has been included. ALL accepted con-tributions are paid for on publication. A special rate is paid for novel experi-ments; good photographs accompanying them are highly desirable.SCIENCE AND INVENTION. Monthly. Entered as second-class matterat Jamaica, N. Y., Post Office, under act of Congress of March 3, 1879.Title Registered at the Patent Office. Copyright, 1923, by E. P. Co., Inc.,New York. The Contents of this Magazine are copyrighted and must not bereproduced without giving full credit to the publication.SCIENCE AND INVENTION is for sale at all newsstands in the UnitedStates and Canada; also at Brentano's, 37 Avenue de l'Opera. Paris. Memberof the Audit Bureau of Circulation.New York City. Western Advertising Representatives. Pacific Coast Advertising Representatives, Kansas City Advertising Representative.Finuean & McClure, A. J. Norris Hill Co.,General Advertising Dept.. George F. Dillon.53 Park Place. 720 Cass St.. Chicago. III. Hearst Bldg.. San Francisco, Calif. Republic Building. Kansas City. Mo.

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842



Discovers AmazingWayto Grow Hair

Alois Merke, Founder of Famous Merke Institutes, PerfectsMethod Which Brings Results in a Few Days

WILL baldness soon be a thing ofthe past? So it would seem-atleast if we are to judge by the re-

markable results being performed dailyat the Merke Institute, Fifth Avenue,New York. For here hundreds of menand women-many of whom were almostcompletely bald - are rapidly acquiringfull growths of wonderfully thick luxuri-ant hair, without even a trace of baldspots. As for dandruff and falling hair,these ailments are often banished afterthe first few treatments with this newmethod.

The discoverer of this new treatmentis Alois Merke, a hair specialist of inter-national reputation. His discovery, whichfor the first time provides a method ofpenetrating to the hair roots and bringingnourishment direct to them, is the resultof a long experience in treating baldness,which included many years at Heidelberg,Paris, Berlin, Cairo, Buenos Ayres andother centers of dermatological research.It works on a plan entirely different fromany known or used before.

At the Merke Institute, Alois Merkehas treated scores of prominent stage andsocial celebrities, many gladly paying $500or more for the marvelous restoration ofhair effected. But, desiring to place hisdiscovery within reach of rich and pooralike, he recently perfected a method

whereby these same results can be se-cured for only a few cents a day right inyour own home. The treatment may betaken in any home in which there is elec-tricity.

Free Booklet About NewHome Treatment

Through special arrangement readersof this publication may secure withoutcost, all details of this new home treat-ment to make hair grow. A 32 -pagebooklet fully describing the Merke treat-ment, will be sent postpaid on receiptof the coupon below, properly filled in.No matter how long you have been bald-no matter if you are completely bald-no matter how many different treat-ments you have taken without results,this booklet will prove of the deepestinterest to you. Sosend for it to -day.Merely mail t h ecoupon and it willbe sent you by re-turn mail.

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844 Science and Invention for January, 1924

JUST OFF THE PRESS1 2 th Edition

WIRELESS COURSE IN 20 LESSONSBy S. GERNSBACK, A. LESCARBOURA and H. W. SECOR

Very Greatly Enlarged

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WIRELESS COURSE20 LESSONS

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This new edition contains over 100 pages more than theprevious editions, of which over 100,000 were sold. It isprinted in a larger type, on better paper and has better andmore illustrations.Lesson No. 1: Principles of Electricity:

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Explanation of Construction and Operation of each of the above, etc.Lesson No. 4: Principles of Wireless Telegraphy:

History and Explanation of the Wave Transmission and those con-cerned in the development of early radio, etc.

Lesson No. 5: Amateur Transmitting Sets and Apparatus:Apparatus and Circuits used by Amateurs in the early days of radiotelegraphy, etc.

Lesson No. 6: Transmitting Sets (Continued):Apparatus and Circuits of Transmitting Apparatus, etc.

Lesson No. 7: Commercial Transmitting Systems:Apparatus and their operation, etc.

Lesson No. 8: Aerials and Underwriters Installing Regulations:Explanation of the Antenna System and Constructional details of thevarious types used. Official regulations, etc.

$Pric:200Postpaid

Lesson No. 9: Radio Receiving Apparatus:Description of the Various Types of Receiving Apparatus with anexplanation of their operation, etc.

Lesson No. 10: The Detector:An explanation of the various types of detectors used for receptionpurposes, including circuits, etc.

Lesson No. 11: The Vacuum Tube as a Detector:Principles of operation of the vacuum tubes, etc.

Lesson No. 12: Regenerative Receiving Set:Description and explanation of various vacuum tube circuits, etc.

Lesson No. 13: The Vacuum Tube as an Amplifier:Operation of the types of amplifiers as in conjunction with tuners.Loud Speakers, etc.

Lesson No. 14: Practical Vacuum Tube Circuits:An explanation of various up-to-date Circuits used in Radio, etc.

Lesson No. 15: Super -Regenerative Receiver:Operation of the Super -Regenerative Receiver, etc.

Lesson No. 16: Vacuum Tube Transmitter:Vacuum Tube Transmission and Broadcasting Systems, etc.

Lesson No. 17: Radio Compass-The Wavemeter-Radio Control!The Radio Compass. Principles and operation of the Wavemeter andRadio Control, etc.

Lesson No. 18: Learning to Operate-The Codes-The Wireless Law:Methods of learning the International Code. Appendix: Detailedregulations of the wireless law. etc.

Lesson No. 19: History of the Development of Radio:A progressive history of radio and those concerned in its progres3. etc.

Lesson No. 20: Mathematics of Wireless Telegraphy and Appendix:Formulas for the Calculation of Wavelength, Inductance, Capacity,and other measurements, etc.

Sent postpaid upon receipt of $2.00If your Dealer cannot supply you, order direct from us, giving Dealer's name and address

Experimenter Publishing Co., 53 Park Place, New York, N.Y.


Science and Invention for January, 1921

A Problem in InventionCan You Solve It?

This simple test will show whether or not youhave inventive ability ; thousands have it anddo not know it, or do not develop it. Yet inven-tion is the easiest way to earn a fortune. Notechnical or scientific knowledge necessary.Read below a few instances of how little ideashave made millions of dollars for their inventors.

HOW would you like to get the royaltypaid to the inventor of the tin capused on millions of bottles? Howmuch money would you have now

had you thought of the simple idea of put-ting rubber tips on pencils ? Wouldn't yougladly be the inventor of the Gillette SafetyRazor, who it is said made as much asTWO AND ONE-HALF MILLIONDOLLARS a year?' The inventor of thetiny snap -fastener recently paid an incometax of $29,000, or be the man whoinvented the President Suspenderswho is now worth $5,000,000. Theinventor of the autographic attach-ment for cameras sold his patentrights. for $300,000.

Ideas Worth FortunesOne single idea-as simple as any

of these - can make you indepen-dently wealthy in a short time. Otherinventors have made hundreds ofthousands of dollars from such com-mon things as the crimped hair -pin,the metal -tip shoe lace, the papersafety match, the ordinary wirepaper clip. These are certainly notcomplicated inventions-they are sosimple, in fact, that probably thou-sands of people thought of them butonly one man DID anything aboutthe idea when it came to him.

You, too, probably have ideas forneeded inventions - and the onlyreason you have not turned yourideas into gold is because, like thousands of otherpersons, you doubt your own ability to invent.Or, like most persons, you believe that an inven-tor must be horn; that every inventor is a manof genius who invents things as naturally as otherpeople do their work as bookkeepers, mechanics,doctors or farmers.

Raymond FWith fourfamous int.makes it easlearn howyour spare t

Invention Can Be LearnedBut this is not true. What were our great in-

ventors before they invented anything. Bell wasa teacher. Edison was a telegrapher. Gillette andWaterman were traveling salesmen. Better proofthan this is that you can satisfy yourself that in-vention is not limited to geniuses or that it ismerely guesswork, luck or chance. You can proveto yourself that invention-any invention. fromthe collar button to the colossal railroad engine-is the result of the same kind of thought that youuse in adding a row of figures.

Just think, for a moment, what you do in anyexample in addition. You see a problem-the rowof figures. You recognize that a result is wanted-the sum of the figures. From these two factsyou go ahead and get the result. And becauseonly one answer can be correct for that particularexample, you know you solve your problem whenyou find that answer.

Proof YOU Can InventExactly the same thing is true in invention.

This is the proof. At the top right-hand cornerof this page is shown a simple problem in inven-tion. What would you put on a shaft "A" toforce members "B B" to move back at the sametime. A little thought will show you the cor-rest answer within a few minutes.

This test of your inventive abil-ity, simple as it is. illustrates thethought behind every invention.Like your arithmetic example yousee first, a problem to be "fixed."Then you think of something whichwill "fix it," something which isthe only correct answer to yourproblem. That is all-that is everything-to inven-tion. Brought down to its plainest definition, in-vention is merely the science of "fixing things,"

And how many times a day you do "fix things.'A leaking faucet, a rattling window, a wabblytable-you fix hundreds of things like these everyyear. And, though you may never have realized

it, every time you "fix things," youuse the very definite exact principleswhich are the basis of InventiveScience!

A

/titde

Here is an interesting little problem in inven-tion. Its solution will be found very simple, ifwe really think.

"A" is the end of a shaft. The two members"B B" are free to move in either direction indi-cated by the arrows. If they are pushed back,the springs "CC" will immediately pull themforward again.

Our problem is to put some kind of an at-tachment on the revolving shaft "A" so that th,members "B B" will be pushed back both at thesame instant every time the shaft "A" makes asingle revolution. The device on shaft "A"must also allow the two members "B ll" tocome forward once in every revolution. Whatwould you suggest putting on the shaft "A"?

. Vales, whoteen otherentors, 1ZOW

for you toto invest inime at home.

What Edi-son SaysCould you ask

the advice of anygreater authoritythan Thomas A.Edison? He says:"Invention is aScience and shouldbe taught as a pro-fession."

And now for thefirst time, you canprofit by Edison',advice. You canactually learn in-vention as a pro-fession - exactlyas other people are

learning electricity. mechan-ics, law, medicine. It doesn'tmatter who you are, or whatyour present work is - youhave the native ability to in-vent. No special knowledgeof mechanics or science is nec-essary.

The Bureau of Inventive Sci-ence offers you the first coursein practical invention ever devised. It has writtenclown the easy -to -learn principles of Inventive Sci-ence so that everybody can read them and learn touse them. The ability to invent was born in you.You already possess the instinct to fix things.What you need now is to develop this ability. thisinstinct so you can use it to pro-duce inventions. All you need, tobecome successful, is this easy, fas-cinating training which will developyour abil-tv so it will be worth realmoney. Fifteen famous inventorstell you WHAT TO INVENT andHOW TO INVENT. They tell youthe secrets of invention which everysuccessful inventor knows. They

New FREE BookThe most fascinating part of this great new

course is. that it teaches invention by actual prac-tice, right in your own home. With each lessonyou are sent sonic problem in invention-just likethe one you worked out here. This fascinatingexercise in solving actual problems in inventionsharpens your instinct to fix things. Better thananything else it gives you an onforgetable, in-stinctive habit of thinking inventively which is

worth more than you realize. Infact, the lessons and exercisesare so simple. so easy to under-stand. so interesting, that theyseem more like a pleasant gamethan like instruction which canmake you a successful inventor.

A wonderful new book, justprinted, tells you more aboutthe Bureau of Inventive Sci-ence and its simple new coursein invention. It costs nothing,so send the coupon at once.Hundreds of years ago. theworld needed only few things,so few inventions were made.But now the world has moreneeds, more things to lie"fixed." Every day you seethings which must be improved.Every day you run into prob-lems which a simple idea cansolve. It may be a new toy foror your children. The man whoinvented the Kiddie-Kar. it isreported, made over $5,000,000.It may be a new kind of soap.E. T. Babbitt is worth millionsof dollars today. It can evenbe a new kind of broom tomake housework easier for mil-lions of housewives. But noTatter what it is-if your ideais practical, if it solves a prob-

lem, if it satisfies a need-a fortune may be wait-ing for you. This bureau is not connected withpatent attorneys or manufacturers. Its only pur-pose is to teach you the principles of practicalinvention used by every successful inventor.Write for the FREE BOOK now.

15 great inventors teach

science,step in inventive,

-How to developimagination

-How to developideas

- How to get the facts youneed for inventions

--How to keep legal recordsof ideas

-- How to use scientific prin-ciples of mechanics

- How to avoid wastingtime on impractical inventions

- How to apply for a patent-How to organize a com-

pany-How to protect your

rights-How to market a patentand hundreds of othervitally important fact,which EVERY successfo'inventor knows and use-.

your

your

explain how to originate ideas, howto develop and perfect them, howto get patents. But they tell youeven more: Thousands of inexper-ienced inventors have been de-frauded of their rewards becausethey did not know how to protecttheir patent rights. This greatcourse tells you everything youwant to know-how to sell yourinvention, how to get royalties-how to get the most money foryour ideas.

Wisner

Bureau of Inventive ScienceDept. 71

Building Rochester N. Y.

Bureau of Inventive Science,Dept. 71, Wisner Building,Rochester, N. Y.

Please send me your free book, "TheScience of Invention,"

Name

Address

City State



ViA'AVT-IVAVAWCYAVAV

BUILD YOUR SET BETTER --AT LOWER COSTSUPER 180° VARIOCOUPLER

H52I Each 98cA wonderful value,

produces excellent re-sults. Green silk wind-ings on black fibretubes. Rigid mountingsupport for table orpanel mounting. Pri-mary tapped for fin -

tuning. Vs inch shaft. Range 200 to 600meters.H522 Variometer-same style. Each 98e

SUPERIOR VARIOCOUPLERH523 Each $3.15

A handsome instru-ment of superior designand construction. Sta-tor tube and rotor ballof moulded red brownbakelite. Large sizegreen silk windings in-sure highest efficiency.Table or panel mount-ing. % Inch shaft. Superior results in cir-cuits for 180 to 650 meters. Tapped pri-mary for finest tuning. Noiseless contacts.

14526 Special single circuit type....$3.60SUPER MOULDED VARIOMETER

14412 Each $2.60Polished black

moulded rotor andstator forms. Maxi-mum inductance withgreatest efficiency andminimum distributedcapacity. A high gradeinstrument that willget the best results.

Wave length 180 to 600 meters.EXCEL MOULDED VARIOMETER

H524 Each $3.68A wonderful value atour price. Properlydesigned and con-structed. ' Polishedblack bakelite rotorand stator forms.large size. Green silkwire insures greatest

efficiency.% inch

haft. Noiseless pigtail connection. Tableor panel mounting.

SUPERIOR VARIOMETERH525 Each $4.45

Forms moulded of redbrown bakelite. A neathandsome instrument.Green silk windings cal-culated for highest effi-s ciency. .4 Inch shaft.Noiseless pigtail canine -lions. Table or panel

mounting. Produces superior results in anytype circuit 180 to 650 meters.

RADIO INDUCTANCE COILSCarefully made - finelooking coils. Highestefficiency. Low distrib-uted capacity effect, lowresistance - high selfinductance. Very firmimpregnation. Rangegiven is in meters whenused with .001 variablecondenser. Mounted coils have standardplug mountings. Art Not Art PriceTurns Range No. kintd. No. Mntd.

25 120- 250 14301 $0.39 H320 $0.8035 175- 450 H302 .42 .9450 250- 720 14303 .49 H323 1.0075 390 910 H304 .54 14324 1.06

100 500- 1150 14305 .58 H325 1.11150 600- 2000 H306 .53 H326 1.15200 900- 2500 H307 .72 H327 1.24250 1200- 3500 H308 .78 H328 1.33300 1500- 4500 H309 .82 H329 1.34100 2000- 5000 11310 .97 H330 1.55500 2800- 6100 H3I1 1.12 H331 1.60600 4000-10000 H312 1.27 H332 1.75750 5000-12000 H3I3 1.43 H333 1.90

1000 7900-15000 H3I4 1.70 H334 2.251250 9750-19500 H315 1.92 H335 2.401500 14500-26500 14316 2.18 11336 2.55

INDUCTANCE COIL MOUNTINGSH340-3 Coil.

14341-2 Coil.$3.40E

Ea. 2.75Sturdy, rigid dur-

able construction.Made of polishedblack bakelite.

Mount on front of panel.BACK OF PANEL MOUNTING

Mounts back of panel, with knobs Scdials on front of panel. Helps make aneat efficient set. 14342 -Each $4.45

COIL MOUNTING PLUGSMade of genuine bakelite.

H344 Plug for mounting"honeycomb inductance coils

39eH345 Stationary plug to fastenmounted coil stationary toPanel 42e

H346 Movable plug to fasten mountedcoil to panel so it can be masted 89eH343 Fibre strip to hold rolls for mount-ing. Two foot piece 15e

SPIDER WEB COILS$4290- 25 turn 39e H292-50 turn 47eH29I- 35 turn 47c H293-75 turn 54c14294-100 turn. Each 68e

A new popular type of inductance of high-est efficiency. Lowest distributed canaeityandlowest high frequency resistance. Flmm greensilk windings with fibre mounting strips.

OUR SPECIAL VARIOMETER AND VARIOCOUPLERBuild into your

set reliable instru-ments. You can de-pend on this vario-meter and vario-coupler to give youthe best results inany circuit workingfrom 180 to 650.meters. In designa n d constructionthey are the best.Only the highestgrade materials areused. The pricesquoted save you 30to 40 per cent.Wh ore?

14418 Varlocoupler. Each $2.45The most efficient type of coupler, insuresbetter tuning and louder signals. Primaryand secondary wound on natural uncoloredgenuine bakelite tubes. Handsome greensilk windings. Primary tapped for finetuning. Can be panel or table mounted.y. inch shaft.

ULTRA AUDION COILH297 Each 85e

Spider web wound of green silk coveredwire. Four taps. Produces wonderfulresults. Fibre strips and wooden rodfor mounting included. Directions fur-l' ed.

STRANDED ANTENNA WIRECabled of fine copper strands. Very flex-

ible. High tensile strength. Rest for aerials.11948 100 ft. roll 58c H249 500 (Leal $2.75

MAGNET WIREInsulated copper wire. Best quality even

drawn wire, one piece to a spool. Pricesquoted are for 8 oz. spools unless other-wise stated.DoubleCotton Enameled Green

Covered Insulation Silk CoveredNumber H990 NI.,nber 11992 Number H99IGauge Price Gauge Price Gauge Price1820

43e 2220 39e 20

26 30

21 2450e 22

24 2655e 2460e65

2360 (4 oz.) 1.2528 ....$1.05 3230 .... 1.45

70e 32 (4 oz.) 1.6590e 30 (4 oz.) 2.20

55170e80e90e

ANTENNA INSULATORS11260 Size lx3%. Compo-sition, metal eyelets. Two°C20 for I7eH263 Ribbed Porcelain M-um sulator. 2% in. long. Ea. 6eDozen 55c

LEAD-IN INSULATORSH270 For 4 inchwalls or less 42eH27I For 9 inchwalls or less 69e

The only practicallead in insulator for aerial wires. Small.neat, effective, durable. Fits % inchhole. Securely locked by two adjustable nuts.

OUTDOOR LIGHTNING ARRESTER11980 Price $1.55Protect your instrumentswith this lightning ar-rester. Weatherproof por-celain case. Air gap type.Permanent. Durable. 'Un-derwriters approved.

HIGH-GRADE LIGHTNING ARRESTERH981 Earls 79eA dependable protector, al-ways on guard. Small andcompact. Weatherproof por-celain rase. Easily fastenedand connected. Underwritersapproved.

BINDING POSTSn Brass, polished nickelas finish. Washer and 6-32

In. screw extending %in.H370 Large size -bar-rel and knob %" long.

H370.2-4 DAE7e2n Stonier size85c

11376-8barre' and knob 9-16" long. Dozen....70e

DozenH-ysLarge size with composition knob.

45eH170 Large size with hole for phone tipor wire. Dozen 800H378 Small size with hole for phone tipor wire. Dozen 350

y pay n$2.10

Perfect in design and construction. Accu-rate wood forms thoroughly seasoned. Cor-rect inductive ratios. Solid baked windings.Plenty of large sized wire insures highestefficiency. A strong high grade instrumentthat will give you lasting service. %, inchshaft.

11410 Variometer. Each

SOLID BARE COPPER WIRESolid bare copper wire for aerials, leads

or wiring instruments.

Solid Bare Copper Wire, size 14.H240 100 ft. coil 48e H242 500 ft. coil $2.25

Solid Bare Copper Wire, size 12.H244 100 ft. col 67e H245 500 ft. roil $3.05

REINARTZ INDUCTANCE142 SI IS

Made of green silkcovered wire, spider -web wound to producegreatest efficiency andlowest losses. 21 tapsso arranged thatcrossing is avoided.Two fibre strips andwooden rod furnishedpermit various styles

of mounting. With this coil a high grade setcan be built at a low cost.Directionsincluded

RADIO SOLDERING IRON

H540 $1.50Soldered connections in radio sets pro-

duce better results. This guaranteed ironis exactly right for radio work. A neatsolid connection quickly and easily made.Operates on any lighting current 100 to120 volts. 8 ft. cord with attaching plug.Length 13 inches. Heats quickly will notoverheat.

Heavier irons for general repair work.Wonderful values at our prices.

H541 Medium size $3.48H542 Large size 4 25

AUTOMATIC BLOW TORCHH543 Each $1.19

Burns denatured alcohol.Automatically generates point-ed flame In a few seconds.Easy to solder joints in hardplaces. Lights with a match.Burns 20 minutes on one fillIng. 5% inches high. % inchdiameter cylinders. Works finewith Tinol listed below.

SUPER BLOW TORCH11544 Each 390

Burns denatured alcohol. VestPocket size. Blowing on tube pro-duces a hot pointed flame. Lightswith a match. Works fast. Burns10 minutes on one filling. Easy tosolder joints in hard places. 3 in.high. 'ifs in. cylinder. Long rub-ber tube. Produces fine jointswith Tinol listed below.

I<I,1

ENCLOSED VARIABLE CONDENSERSOne of the best made con-

densers. Rigid, accuratelyspaced aluminum plates.Formica ends. Engravedscale. Knob and pointer.Clear transparent case.H806 43 plate .001Mfd. $2.80

H808 21 plate .0005 Mfd. $2.45

PANEL MOUNTING VARIABLE CONDENSERSThese are especially high grade con-

densers and we guarantee them to be me-chanically and electrically perfect. Finepolished end plates of heavy bakelite.Shafts % inch diameter. Sturdy, heavyaluminum alloy plates perfectly spaced toinsure smooth, even, reliable capacity.Our low prices save you money. These

- Icondensers are of the very best make and

r or,r- condensers offered. guar -are not to be compared with many infe-

cheap- antee them the please you or your mane]back. The rnier style has one

We

sepa-rately controlled plate which permits ofthe finest tuning.

H8I5- plateeGULAR STYLE

58c14816- 5 plate 97eH8I4-11 plate .00025 mfd. $1.28 H825-14 plate .00025 mfd.H813-21 plate .0005 mfd. 1.35 H824-26 plate .0005 mfd.H812-43 plate .001 W.I. 1.58 H826-16 plate .001 mfd.

VERNIER STYLEIncluding Dial and Knobs

$2.452.753.15

OUR SPECIAL AUDIO FREQUENCYAMPLIFYING TRANSFORMERS

H550 Each $2.25The result of years of

research work and experi-enced engineering. Inquality of tone and vol-ume of sound, the thingsa transformer is built for, we guarantee itto equal or surpass any other transformer.Neat in appearance. Carefully made. Fullymounted with plainly marked binding postconnections. 5 to 1 ratio. Wonderful re-sults on one, two or three steps withoutdistortion or howling. A quality item inevery respect. Not to be compared witharticles built for price only.

OUR SPECIAL SHIELDEDTRANSFORMER

1155I-5% to 1 Ratio.Each $2.55H552-6 to 1 Ratio.Each 2.75

The same high gradestyle of transformer as aboveenclosed in a metal case

which completely shields it from any out-side magnetic influences. Very attractiveappearance and sturdy construction. Freefrom howling and local disturbances.

OTHER STANDARD BRANDS AUDIOFREQUENCY TRANSFORMERS

Fresh, clean stock in original containers.H232 Thardarsen Ratio 3% to 1 $3.40H233 Thordarson Ratio 6 to 1 3.80H553 Acme. Each 4.45H554 Coto. Each 4.45H555 Federal. Each 4.45117I2 Radio Corp. Each 6.40H234 All American 10 to 1 Shielded 4.15H239 All American 5 to 1 Shielded 4.10H236 All American 3 to 1 Shielded 3.95

RADIO FREQUENCY AMPLIFYINGTRANSFORMER

11560 For 201A or 301ATubes $1.70H561 For 199 or 11 or 12Tubes $1.70

Due to its special designthis transformer will producewonderful results in any type

of regular or reflex radio frequency circuit.While law in price we believe It equal orsuperior to higher priced transformers.Perfect for one, two or three stages. Com-pact, convenient form, easily mounted.Range 175 to 600 meters. Try R. If youare not satisfied return it and get yourmoney back.

OTHER STANDARD BRANDS RADIOFREQUENCY TRANSFORMERS

H568 Our special -as good as any ofthem $ .48H562 Dubilier. Each 4.45H563 Ccto. Each 4.45H565 Acme. First stage. Each 4.45H568 Acme. Second stage. Each 4.45H567 Acme. Third stage. Each 4.45H714 Radio Corp. Each 5.95H995 All American. Each 3.9511575 Erla. First stage. Each 3.55H576 Erla. Second stage. Each 3.55H577 Erla. Third stage. Each 3.55H578 Erie. Reflex. Each 4.45

NEUTRODYNE TRANSFORMERSH57I Per set of three $4.95

An air core transformer for use in neu-trodyne method of reception. Can also beused for tuned radio frequency or as a fixedcoupler with condenser across secondary.Proper design for results and efficiency.Green silk windings on bakelite tubes withadjustable mounting brackets to fit mostany condenser.

NEUTRALIZING CONDENSERSH572 Per set of two 40c

Simple, inexpensive, effective precisiontype. Micrometer adjustment is attainable.Easily mounted in circuit.

SPECIALH573 Neittrodyne Jack. Each 89e

LONG NOSE PLIERSH970 Price 95e

32.-T h e handiest

pliers for radiowork. Made of

finehardened steel.Length, 5 in.

DIAGONAL JAW NIPPERSH972 Price. ...$1.05

For fine electricalwork, made of hard-ened steel. Length, 5aches.

FOUR -IN -ONE

0 oll NR

H974 Each

Serew.

Especially suitable for radio work. Willligna Dr Ivgcr.Innesa=a,

handle any size screw used. Smaller driv-ers neat inside larger one and are held inplace with screw cap. Made of steel, nickelfinished,

TINOL H969 Per tube...19eA combined solder

and flux In handyform. Put a little onthe connection, heatwith a match, torch

or solder iron and you have a nest elec-trically and mechanically perfect joint.

THE BARAWIK C I Beware of Imitators

Chicago's OriginalRadio Supply House 102 South Canal St., Chicago, Ill.

!%%%%%%%%%%%%%!.eWedleleedWAVWWWWWAVV1WeWeeeis


Science and Invention for January, 1924 Sq7

s'e weeeiliNVAIWANWMAWIPMeeieleierneeeemio Y. MiWireei%

WITH BARAWIK STANDARD RADIO GOODSVACUUM TUBES

Standard Brands -Cunningham,

"Radlotron. Every one guaranteednew and perfect. e will ship

1 brand In stock unless you speci-fy otherwise.H105 Detector 1'5'200 0300Each $4.38HI12 Amplifier, CV201AC301A. 5.85H118 Ts -Watt Transmitter 7.70H107 %VIM Cll. Each 5.85H101 WDI2 C12. Earls 5.85

H102 UV199 1'299. Each 5.85HIG4 UV199 Adapter fits 199 tube tostandard socket .42H108.\VDI1 Socket. Each .31

H 109 WD11 Adapter. Earls .45

1111

STANDARD TUBESOCKET

H14.1) Each 39cMoulded of genuine red

brasses Bindingpost connections. F o rtable or panel mounting.Neat and strong.

METAL TUBE SOCKETH 146 Each 39c

A strong durable socketfor panel or table mounting.Metal tube and base. Plain-ly marked binding post con-nections well insulated.

TWO AND THREE GANG SOCKETST 11 e e e socketssnake it easy to lryfrprill,build detector .:4and amplifierunits and makea neat, compact workmanlike job.11147 Two -gang socket 95cH 149 Three -gang socket $1.3n

199 SOCKETH 145 Each 490

Moulded of high insulatingmaterial. Sponge rubber baseprevents ringing in tube.Plainly marked binding postconnections. Neat and compact.

FILAMENT CONTROL RHEOSTATSHI32.6 ohm. Each 45cH 129 20 ohm. Earis 52cH131 30 Wins. Each 59cHI35 6 ohm Vernier 95c

Best grade. Will givereal service. Durable andlasting. High heat resist-ing base, diam. 2% in.

.Tapered polished black knob II, diem.Potentiometers. Match above rheostats.

Sante high grade construction.H 151 201) Mins. Each 79eH152 400 ohm. Each 79c

SUPERIOR RHEOSTATSHI53 6 ohm. Earls 69cHIM 20 ohm. Earls 76cH 155 30 ohm. Each 83c

The finest rheostat. Smooth,even action. Best design, bestworkmanship. Supplied with at-

tractive dial and knob. A rheostat for highgi adds sets.

Potentiometers to match above rheostatswith dial and knob.H 156 3011 ohm 98c

QUICK ACTING RHEOSTATH124 6 ohm. Ea....79cH 125 15 ohm. Ea...88cHI26 30 ohm. Ess...99c

Vernier adjustment atevery degree of resistance.Pushing knob in turns offthe filament.

THREE INCH DIALH923 For 3-16 inch shaft.

Each 22cH924 For 1s inch shuts.Each 22c

A handsome neat lookingdial moulded in one piece of

polished black composition. 180° scalemarked 0 to 100 finely engraved in con-trasting white enamel. Diameter 3 inches.

TWO INCH DIALH92I For 3-16 inch shaftEach 168H922 For 1/2 inch shaft.Each I6c

A handsome dial moulded inone piece of polished black com-position. 270" scale marked 0 to 100 finely H766engraved in contrasting white enamel. Fine H619for rheostat or switch control. Diem. 2 In. H618

VERNIER DIAL ADJUSTERH941 Each 19cEasily installed at edgeof dial, gives finest ver-nier adjustment of con-denser or inductance. A

great value. Polished black knob.BAKELITE DIALS

H93I-2 In. Mans. for3-16 in. shaft. Each 35cH932-2 in. Diem. for% in. shaft. Each....35gH933-3 in. Diam. fuse

3-16 in. shaft. Each..39eH934-3 In. Diem. for% In. shaft. Each...39e

H935-4 in. Diam. for Y. in. shaft. Ea. 48cMoulded in one piece of genuine bakelite

In polished black finish. Finely engravedscale in contrasting white enamel. Suregrip knob that fits the fingers. Highergrade dials for good sets. Sizes match per-fectly.

WE PAY TRANSPORTATION CHARGES EAST OF THE ROCKIESPRESERVE THESE PAGES - ORDER FROM THEM AND SAVE MONEY

FAST SERVICE -TRY US AND BE CONVINCEDTHE PRICES QUOTED DELIVER THE GOODS TO YOUR DOOR

OUR GUARANTEE PROTECTS YOU -We handle only the best goods, carefully testedand checked by expert radio engineers. You are assured of getting guaranteed appa-ratus that will give superior results. And while our goods are best. our prices are low-est. Our goods equal or surpass the claims we make for them. We do not attempt todeceive or mislead. Our reputation for fair dealing is our most valued asset.

HOW TO ORDER -Write your Order plainly, state Article Number, Description andPrice of items wanted. Send Postoffice or Express Money Order, Certified Check orBank Draft for Total of Order. Prompt Shipment is assured when these directions arefollowed.

ENCLOSED DETECTOROne of Use finest crystal

detectors on the market,supersensitive galena crys-tal enclosed in heavy glassshield. Quick, positiveadjustment. Brass partspolished nickel finishH730 Each 89t

GALENA DETECTOREasy fine adjustment.

Crystal mounted in cup.Moulded base and knob.Brass pasts polishednickel finish. An un-equaled value.

H732 Essrls 59c

GREWOL CRYSTAL DETECTORH742 Each $1.69

DETECTOR CRYSTALSH736 Galena, Arlington tested niece 19e14738 Silicon. Arlington tested, piece 19e14735 Tested. Galena, Mounted, piece 9c11737 'rested, Silicon, lice Dime 9cH739 Genuine million point crystal. Ea 29cSUPERIOR VARIABLE

GRID RESISTANCEHI67 Earls 80cH 168 1N'ith .smo25 Con-denser 959Eliminates hissing, clar-ifies signals. Capacitysmoothly varied from 0 to 6 megohms byhalf turn of knob. Easily mounted on anypanel.H I71 Freshman said mounting variablegrid leak with .00025 condenser. Each 69eH 172 Durham variable grid leak withmounting. Each 89eH 173 ('RI. Variable grid leak. Earls $1.19

TUBULAR GRIDGRID LEAKS ANDCONDENSERS

Very convenient.Permit of quickchange of leaks orcondensers of varyingcapacity. Cut showsleak mounted, Leaks

and condensers have same appearance. Eachpart priced separately.H849 Grid Leak. Each 18e

Resistances -34, 1, 11/2. 2. 3. 5. 7, and10 megohms. Specify which size is wanted.

H831 Grid and I'lato Condensers. Ea. 39cCapacities -.00025, .0001, .00025, .0005

mid. Specify which size is wanted.

Mountings. Bakelite base.wain Single mounting. Each 28eH842 Double mounting. EachH844 Triple mounting. Each

47p67c

SUPERIOR INDUCTANCE SWITCHH288 Earls 74c

Quickly and securelymounted by drilling onehole. Only knob andpointer show in front ofpanel. Connections ranIse soldered before fast-ening switch, makingassembly much easier.Metal parts nickeled.Bakelite knob and supporting base.STANDARD BRAND LOUD SPEAKERS

AND UNITSH610 MurdockH611 RiroH613 Baravik with Italdnin unit..11.25H615 Pattie 19.50H616 Atlas 21.50H612 Magnavox R3 32.50H614 Magnavox 311 32.50

Music Master 27.00Genuine Baldwin type C unit 5.35Stitrdock Special Unit 2.60Brandes Table Talker 8.75

H620 Baldwin Loud Speaker 22.50

$4.384.85

ing contacts.

SUPERIOR RADIO JACKSFinest grade jacks.

Improved design.Best materials.Phosphor bronzeaprings. Silver con-tact points. Nickel finish. Mount onpanels % to % in.H390 Open circuit. Each 36cH391 (lobed circuit. Each 45cH392 Two circuit. Earls 54cH393 Single circuit filament cont 58c11394 Two circuit filament cont 74c

COMPETITOR JACKSH387 Open circuit. EachH388 'rwo circuit. Each 35c

Well made, durable, smooth working.nickel finished frame. Well insulated.

SUPERIOR RADIO PLUGSH395 With s e tscrews for fasteningcord. Each ...35eH397 Two -war -takes two pair anystyle cords. Each 59eHighest grade plugs. Fit any standardPicks. Polished round barrels.

SWITCH CONTACT POINTSBrass polished nickel finish. All

have % In. long size 6-32 serest/and two nuts. All prices the same.Dozen 15e Hundred $1.00

Order by Article Number.H360 Head, 54" dians.; a" I, I gh11362 Head, 3-16" dians.; 14" high14363 Head, 3-16" diens.; 1-16" !sigh

Solder Lugs to Fit Contact PointsAlso for connecting wires to

binding posts, etc.ce

H365 Dozen 8e Hundred 30e

SWITCH LEVER STOPBrass polished nickel finish.H386 Dozen 18c Hundred $1.05

27c

SWITCH LEVERSVery neat polished black com-position knob. Exposed metalparts polished nickel finish.Fitted with panel bushing andtwo set nuts. A high gradeswitch.H381 11/4" Radius. Earls 15c

INDUCTANCE SWITCHH285 Price includingknob and dial..$1.29Mounts switch pointsand contact lever be-hind panel. Only onehole needed to mount.15 switch points, anynumber of which maybe used. Smooth win -

Attractive tapered knob.CABINETS

Fine looking cabi-nets solidly built.Elegant hand rub-bed dark mahoganyfinish. You will heproud of your setmounted in one ofthese cabinets.Hinged tops. Front rabbeted to take panels.Panels not included. Prices are transpor-tation paid.Panel I inside Dimensions Art. 'PriceSize I High 1 Wide 1 Deep No. I Each

65 7" 514"I 61/2" 7" H4201 $2.156:101/2" 51/2"I 10 " 7" 144221 2.657:10" 6,40,I 9th" 7" H421 2.907x12" 61,4" 111/2" 1 7" H424 I 3.057214" fi1/2"1 131/2"

I 7" H423 I 3.207s18" 61/2" 171,4" 7" H426 3.457521" 634" 2034" I 7" H425 3.857524" 6%"I9514" 01/4"1 131/4

2334" I 7" H429 4.65" I 10" 14428 .55

12x14" 11%"I 1334" I 10" 1143034.V

12x21" 111/2"1 204" 1 10" H432 5.45BARAWIK QUALITY HEADSETS

11770 1 er Set, 2000 alms 53.25These headsets have proven on rigid tests to be one of the

eery best on the market. The tone quality is excellent withan unusual volume. Skil ed workmen make them from onlydie best selected material . The receiver cases are fine pol-ished finish with polished black ear pieces. Fabric coveredhead band comfortably and quickly fitted to the head. Suss -Plied with 5 -foot cord. These sets were designed to sell Tom

much higher prices than we ask. and at our price are a won-derful bargain. We guarantee that you will be pleased withthem and agree that they are the best value by far yet offered./f they don't suit you we will cheerfully return your money.

STANDARD BRAND HEADSETS11754 Baldwin Type C withuniversal jack plug $10.955756 Red -Head, 3000ohm 5,785768 Brandes, 2000ohm 4.905769 Brandes, 3000ohm 6.75

H751 Murdock 56, 2000ohm $3.59H752 Murdock 56, 1000ohm 3.95H764 Frost, 2000 ohm 3.59H766 Frost, 3000 ohm 4.15H758 Western Electric 9.50

PLATE CIRCUIT "B" BATTERIESYou can make real sav-ings on these batteries.Don't pay more. Weguarantee them to equalany on Use market re-gardless of price. Ab-solutely uniform. Ex-tra long life.HI80 Signal Corps type, small size. FS

cells, 22% volts. Each $1.1014182 Large size. 5 taps 16%, 18, 1914.2I and 22 volts. Each $1.59H184 Variable Large Navy size, 16%5453inches 5 taps, giving range from 16% to22% volts in 134 volt steps. Each 51.9511188 Combination Tapped 45 volts, NIcell, 13'453 battery'. Tapped to give 45,22%, 21, 19%, 18 and 16% volts. Handlesboth detector and amplifier tubes. Ea. $3.65

"B" BATTERY METERHI89 Earls 98c

Reads 0 to 50 volts. Accu-rately tells you the exact Cats-dition of your It Battery. Con-venient watch size. Polishednickel case with wire lead.

STORAGE "A" BATTERYA very Isiah gradebattery made es-pecially for radioservice. Guaranteedfor t Is r e e years.Properly cared forwill give many moreyears of service forfilament lighting.Made of best newmaterials. Full ca-pacity. The bestbattery buy on the market. Try one of thesebatteries on your set for 10 days. If at theend of that time you are not fully satisfiedwith the battery return it and we will re-fund the. purchase price.H194 6 volt, 40 ampere size. Earls $10.75HI96 6 volt, 80 ampere size. Each 13.25

HOMECHARGERBATTERY CHARGING RECTIFIER

Charge your battery at home overnight for a few cents. Simply con-nect to any 110 volt 60 cycle lightmarket, turn on current and recti-' flee does the rest automatically.Will work for years without at-

tention. Simpleconnections. Give,a taperingcharge which bat-teries shouldhave. Yost c a n

it aProfit chargingSt o ts r friends'auto batteries.Long connectingcords with pairof battery clips.

H201 For 6 volt battery $12.95H203 For 12 volt battery 12.95

HYDROMETER11190 Each 48c

Accurately tells you the condition ofyour storage battery. Helps you keep yourbattery in better condition.

BATTERY CLIPS

Clip onto storage battery28cHI98 Two for

terminals, lead coated. MakePositive non -corrosive contact at all times.

WIRE CONNECTING CLIPSHI99 Per dozen 30c

Small connecting clips forQuickly fastening leads on-to binding posts, etc. Handy

and useful. Every radioiot should have atleast a dozen.

oo,

RADIO "BAKELITE" PANELSNotice our very loss prices on this fine

quality material. Others ask as much forhard rubber panels which are worth muchless. We supply genuine Bakelite, Con-densito Celeron or Formica, all of whirlsare materials with practically identical me-chanical, chemical and electrical proper-ties. Machines well without chipping.Won't warp. Waterproof. Highest me-chanical and dielectric strength. Attractivenatural polished black finish which can besanded and oiled.

Panel 34" thick 3-16"thiekSi" ArtInches No. Price No.' Price

65 7 H450 $0.57 H460 $0.8, 11470 $1.156:001/2 H451 .86 H461 1.27 H471 1.737:14 H458 1.38 14468 2.07 H478 2.767:18 H453 1.78 11463 2.65 H473 3.567:21 H457 2.05 H467 3.05 H477 5.107524 11459 2.42 H469 3.569:14 H454 1.85 H464 2.65 H474 3.56

12514 H455 2.42 H465 3.56 H475 4.7812:21 H456 3.62 H466 5.35 11476 7.13

1/2" thickArt.No. Price

RUBBER COMPOUND PANELSMade of a special compound having a rub-ber base. Equal in appearance and in allessential points to any other class ofpanels. Fine smooth polished finish. Canbe drilled or cut without chipping. Guar-anteed not to warp and to be a perfectinsulator for radio use. Smooth, cleanedges. Thickness 3/16 inch. Size givenis in inches.H481 1xio ..$ .88 H484 7x18...51.6011482 -x12... 1.05 H485 7x21... 1.85H483 7:14... 1.22 11486 7:21 . 2.10

THE BARAWIK CO. v'Bteillor7sie117:14t!'bi:r!s 102 South Canal St., Chicago, Ill.


84E Science and Invention for January, 1924

New York Electrical School29 W. 17th St., New York N. Y.

Please send FREE and without obligation touse your 64 -page book.

NAME

STREET

CITY STATE

Master Electricity ByActual Practice

The only way you can become an expert is by doing thevery work under competent instructors, which you will becalled upon to do later on. In other words, learn by doing.That is the method of the New York Electrical School.

Five minutes of actual practice properly directed is worthmore to a man than years and years of book study. Indeed,Actual Practice is the only training of value, and graduatesof New York Electrical School have proved themselves tobe the only men that are fully qualified to satisfy EVERYdemand of the Electrical Profession.

The Only Institution of the Kindin America

At this "Learn by Doing" School a man acquires the artof Electrical Drafting; the best business methods and ex-perience in Electrical Contracting, together with the skillto install, operate and maintain all systems for producing,transmitting and using electricity. A school for Old andYoung. Individual instruction.

Over 8,000 Graduates are Successful Menin the Electrical World

No previous knowledge of electricity, mechanics or mathematics isnecessary to take this electrical course. You can begin the course nowand by steady application prepare yourself in a short time. You willbe taught by practical electrical experts with actual apparatus, underactual conditions.

The N. Y. E. S. gives a special Automobile Ignition Course as anadvanced training for Auto Mechanics, Garage Men and Car Owners.The course covers completely all Systems of Ignition, Starters, Lightingand other electrical equipment on automobiles, motor boats, airplanes,etc.

Let us explain our complete courses to you in person. If youcan't call, send now for 64 -page book-it's FREE to you.

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29 West 17th Street, New York


ell$1111111,11111111.11111111.111,111, ttttt III tttttt

Volume XIWhole No. 129

AN1111/111/14110011114111111 llllllll

Editorial

H. GERNSBACK, LDITOR AND PUBLISHERH. WINFIELD SECOR, ASSOCIATE EDITORT. O'CONOR SLOANE, Ph.D., ASSOCIATE EDITOR

and General Offices, - - - 53 Park Place, New York

tet

JANUARY1924

No. 91111111111111101l1111111111111111111111111111.111.11111111111111111111111.1.

k11.1.Lui.......0111114.111140.11a,MlLIdtJI.1.11111.411.1.1111.1111.1.51 lllll 111.11 lllllll 111111111111111,1111111111111111111111111111111111111111111111111111.1111.. ,

... .,1.111.1111

"Those Who Refuse to Go Beyond Fact Rarely Get As Far As Fact HUXLEY

GERNSBACK

New York City.Dear Sir:

The pleasure which I derive from your editorialscan never be determined. They are the best I have

ever read, yet there is one thing which I11' have often wondered about, and which I

have never seen treated on your editorialpage of SCIENCE AND INVENTION.It is mans evolution. Many of the sciencemagazines have completely over -stressedthe question.

I am sure your readers arc earnestlylooking for your opinion concerning this

1Y11WYWWw11WYW1 ,1111,1,1 subject. It would be very much appreci-ated if we could read your views of the

above in the next issue of SCIENCE AND INVENTION.Thanking you I am ,7 ery truly yours,

(S) FRANCIS L. WADSWORTH, JR.Radio Editor of Macon County School Review,

Tuskegee, Alabama.The writer must thank the sender of the above for his letter.

The writer had no idea that so much attention was paid to his edi-torials. He has been writing them for years as a sort of hobby,which was hard to abandon, but it is gratifying to see that there arereally people who read them.

The reason the writer has never written an editorial on man'sevolution is, that the subject is so vast, that it is almost impossibleto treat it successfully in a short editorial. One of thebest works on man's evolution that the writer ever cameacross is H. G. Wells' "Outline of History," with whichthe writer is very much in sympathy. In the main, itexpresses the writer's ideas. The following, however,will give a few of his own observations on man's evolu-tion at random.

Life began on this planet the minute the earth hadformed a solid crust and had cooled off so that waterwould not boil on its surface. At that time evolutionon this planet commenced. Just how life actuallybegan at first it is impossible to tell now. The reason is that we donot know now what life really is. But it seems probable that the firstliving creatures came from the muck and slime collected bysea waters on beaches. In other words, life first came out ofthe depths of the ocean. This seems pretty well established today.Man is a descendant of fish. Man's spine and the spine of a fish arein principle the same. Even man's hair can be directly traced to fishscales.

Of course, all this evolution is extremely slow. From the firstfish to the first prehistoric man, you will findthat the time must be measured in millions,if not billions of years. Evolution on thisplanet in general is very slow and verygradual. It takes tens of thousands of yearsbefOre a change can even be detected. TheEgyptian mummies that we find today,although perhaps five or six thousand yearsold, are practically the same anatomicallyas ourselves. In other words, a span of5,000 years in man's evolution means nothingat all. How could it be otherwise when only58 generations have elapsed since Christ was

I BELIEVE¶ THAT you can'tbelieve everythingyou see with yourown eyes.

L." THE GOLDEN AGE OFSCIENCE

is now symbolized by the goldencover of SCIENCE & INVEN-TION. LOOK FOR THE GOLDCOVER every month!

. I I 1 I 1 I I ILI I L 1.1 I I 1,1. I 1., I I 1.1 1 1 I I I I I I .11 I, 1.1 II I I 11 1 1.1I I I, I, I I 1 1 1.1 1 I I I 1 1 I I I 1 I I I I I I I I I

wermittintiumegunTrummti

BELIEVE¶ THAT there isnothing more mindennobling in thewhole world thanastronomy.

lllll 11111W1111111.111111:11.11111111111111111111.1,...,........1

born nineteen hundred and twenty-three years ago, and only 178generations have elapsed since the earliest Biblical times, figuringthe average life at one-third of a century. Every breeder of horsesand dogs knows that the process of evolution is extremely slow.Many generations must be passed before even the slightest changeis possible.

Before man had acquired speech, it isvery probable that he roamed the prim-eval forests much as wild animals do to-day. He probably was entirely coveredwith hair and there is no question that inmany respects he resembled a large mon-key. This does not mean that man hasdescended from monkey or that monkeyhas descended from man. During theprocess of evolution there probably camea time when a so-called "split" arrived, of which the human race isone branch and of which the monkeys are another branch; butthat both descended from the same common ancestors there is noreason for doubt. All of our ancestors originally came from thesea.

Our abode then was probably the primeval forests. That theearliest man dwelt in trees, there is today no doubt. Down toour present day, the instincts still lead back to the forests. Nearlyevery human being still dreams of falling through space. This canbe traced directly back to the time when we were still living intrees and when one of the greatest dangers to the race was thefalling from a tree into the fangs of some prowling beast.

Nearly every man, particularly those who go hunting, know thestrange feeling that comes to them when followed inthe dark. The hair of the back of the neck begins tobristle in a disagreeable manner. This, even today, iscommon in many animals such as monkeys, dogs, etc.

Even the panic -stampede of human beings can betraced directly to the forests. A man when alone hasan entirely different psychology than a man in a crowd.The collective stampede of the human race is an exactcounterpart of the animal stampede as it exists withmany animals.

One surprising thing that the writer has alwaysbeen concerned with is: How many times has a "human" racebeen evolved during the past millions of years. By that ismeant animals-not necessarily resembling man-that couldtalk and REASON as human beings do. But there is apossibility that such a race lived on this planet, having longbeen supplanted by other species under Nature's own law ofthe "survival of the fittest."

Of course, it might be said that under this classification, suchhighly developed insects, as for instance the ants and the bees, would

come. Many entomologists are of the opin-ion that both of these insect classes reallydo reason, which the writer does not deny.But it might be said that there can be severalclasses of reasoning. For instance, it may bedoubted if either the ant or the bee knowsanything of astronomy, of scientific researchwork, of chemistry, etc. In any event, bothof these classes of insects are much olderthan the human race, but neither of themseem to have made use of the planet's treas-ures. So far, only the human race seemsto have had this "gift."

I BELIEVE11 THAT most suc-cessful inventorsare made - notborn.

J

849



GARAGEAND

PARKING,LEVEL

Glass

lass Enclosed CityEnclosed Community to Have Artificial Heat and Rain.

MOVINGthe tropics into the heart of New York, or even further north, is the vision

of the American Society of Heating and Ventilating Engineers. A plan for enclos-ing an area of more than a half mile square in one great heat insulating shell and heat-ing and ventilating it-even providing artificial rain-so that the weather may be at alltimes convenient to the inhabitants is published in the current number of the officialorgan of the Society, the Journal. The structure is to be enclosed in gypsum, or otherheat insulating material and glass. Note in the plan how the sky -lights are arrangedso that during each day there will he sunshine over the whole area of the enclosure,The tops of the buildings within will have artificial lakes which will further help tokeep the temperature constant. All transportation will be carried on in subway tun-nels and on roadways on the roofs of the houses. The street areas will be given overto parks where trees and shrubbery will be grown. It will be possible for the house-holder to grow two or three crops of vegetables on his truck patch on account of theregulated temperatures and the well regulated showers. The houses themselves withinthe community will be built upon the tropical principle-mere shells for privacy only.The plan is the idea of a well known Chicago heating engineer and $16,500,000 is the

estimated cost of the project of the dimensions shown.

ELEVATOR FROMSUBWAY LEVEL TO

ROOF ROADWAY

./-l1;11illID ,,

Aril 4'"'

OrTith '14'i ...ci.-7--biol,;,.11, ,,,pi, il III ,,

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ir.' s ,,

NAPARTMENT HOUSES

'1 STORIES HIGH. HAVINGA POPULATION 4,4

OF 65,000 Nt_

.e.i

DOUBLE GLASS.CAN BE OPENED

IN SUMMER

ROOFPROMENADE_ (CISTERNS UNDER

00F. WATER USEDFOR FIRE ANDARTIFICIAL RAIN.

POWER:HEAT AND

LIGHT PIPES

sit SMALL HOUSESWITH GARDENS

141

r(

X11 X111

Drawn 'sy L. Biederman e -1923-11y Science & Invention



ovies anufact

Here is shownthe machine de-vised by t h eMetro Studios,f o r producingartificial light-ning effects. Itshoots a flametwo feet in di-ameter twentyfeet in the air.The flash is made bya mixture of gyro -aluminum powder,acetylene, oxygen andcompressed air.

re wn LightninMachine Shoots Two -Foot Flame Twenty Feet In Air.

Above is shown the machine in operation with the truck andbuilt-in air compressor. Only two men are required tooperate the device. At the top right is shown the largepowder tank, oxygen and acetylene containers and controls.

131acls Phtning

In spite of the fact that practically no explanation whichreally explains the nature of the so-called black lightniig hasbeen brought forward there seems to be no end of evidenceas to its actual existence. Above is a photo of the phenome-non taken recently at Spokane, Washington. by T. L. Walker.The original photo was taken or a five by nine plate and ina perfectly ordina-y way. It was taken at night with a smallexposure and the lightning furnished the only illuminationfar the plate. The smaller reproduction shown her is a re-duction from the original plate. Some scientists have goneto great length to prove that this phenomenon is the workof some defect in the photographic process or due to somepeculiarity in the plate or in the camera

In the diagram: A -Acetylenet ank, B -Oxygen tank,hi -Small acetylene tank

for pilot light. E -Compressedair tube. D-Pyro powdercontainer. 0, P, Q and R.Gas and powder mixers.Powder is forced up tube.

Control for thepowder is atthe bottom ofthe funneltank. Gases arereleased aroundthe spray ofpowder at thenozzle opening.Phil Gersdorf.

Photo 'raphs of Eclipse

111

s

A complete photographic record of the eclipse of thesun last September 10, taken at Akron, Ohio, by W.E. Burton. The camera was set in a fixed position,stopped as far down as possible. One of the images

is partly interfered with by a tree.

At the left above is shown another composite photograph of the eclipse that was obscured for a period of thirty minutesby a passing cloud. This ogres was made at Scranton, Penn. The cloud moved in the way after nine, five-minute ex-

posures had been made:. The exposures began at 4:10 P. M. The last one was made at 5:25 P. M.


85') Science and Invention for January, 192-/

CoRe and Oil As Coal' Su stitutesBy -Product Coke and Oil More Efficient Than Coal.

HARD COAL BY-PRODUCT(ANTHRACITE) COKE

8(020'10LOWER EFCIENCY

1/

SOFTCOAL

RELATIVE EFFICIENCY -HARD AND SOFTCOAL AND BY-PRODUCT COKE

YOURFURNACE

COST OF OIL BURNER.EQU1PMENT-$ 150,00 to

$ 550.00

YSMOKE ANDGAS

SOFT COAL

OIL FILLINGCAP

AW0,:-HflainTim

BURIEDTO.5 FT

0 > 52 DIA

STEEL TANK,I777 GALS.OI L CAPACITY:(74 GAL. RATE) '

TANK 5 FT. LOTIG X 3FT.DIA.CAPACITY.264 GAL FOR 104 GALRATE

130 GALS.011.1TOtiCOAL{:41.4ic',14,213TorloCIt'h EPOV.110LWA LENT

NO SMOKEOR SOOT

BY-PRODUCTCOKE I I

18 DEPTH GOODAVERAGE FOR.COKE FIRE.

DONT LET ASHESPILE UP ANDTOUCH GRATE

BURNED GRATES RESULT

OIL BURNER ATTACHE() TO FURNACEWith the ever-increasing difficulties connected with burning coal and the attendant dirti- (between 10 and 20 per cent more than bituminous). Their method suggested to burnness, the U. S. Bureau of Mines, after a full investigation state that it is not only the by-product coke is shown in the upper right corner. Careful regulation of themore economical but cleaner and easier to fire coke and oil in homes and small build- draft is necessary. In burning oil, the main problem is that of securing a tankings than coal. Their tests show that coke burns with the efficiency of anthracite coal large enough to get the cheapest rate on the fuel delivered. Details are shown above.

TUR INE-LIKE MACHINE FOR TUDE POWERBY DR. H. BECHER.

_-By housing a common design tidal turbine within a case arranged with a system of valves, German engi-neers have completed a machine for the utilization of the power of the sea that works as the tide flowsin both directions. When the tide is incoming the water flows in through the valve V1, through the cyl-inder, into the turbine and out at valve V4. When the tide changes direction the other two valves ofthe appliance come into use and the water follows the path from V3, through the cylinder, over the turbine andout at V2. Thus the direction of operation of the turbine is the same at all times. Above is shown a view ofthe complete arrangement as it looks installed. At the right is a diagrammatic arrangement showing the pathof the water as it passes through the machine. The device shown in the illustration is used for pumping water.



Autorarnofive Emprovementa of the Year

I BALLOON TIRES

Recent Advances Shown at New York Auto Show.

ONE SPEEDCONTROL LEVER(NO GEAR \

SHIFT) 1

LIOUIDIDIOPUMP LIQUID

/ TURBINE(MOTOR

EQUALIZINGTANK - 4

HYDRAULIC `'.16414j*-- TO4 TRANSMISSION REAR WHEELS

GEAR SHIFTLEVER

TO REARPROPELLER

SHAF7

low, TO CLUTCHSHAFT

4lSLIDING KEYS

THAT LOCK GEARSIN PROPER ::;EQuENC

2 NEW GEAR SHIFT

GEARS-ALWAYS\ MESH

Most of tl-e radical changes in the design of motorcars and their equipment, during the past year, have

been in connection with braking and gear transmis-sion. At 3 are shown the new -Balloon" tires, sevenand one-half inches in diameter for the ordinary tour-ing or closed car and inflated to only 25 pounds pres-sure. The manufacturers claim that cars equippedwith these tires have more braking surface than thenew four -wheel -brake cars. A comparison of thebraking surface of the balloon tires and the ordinarytype is shown in the illustration at ].A. The four-wheel -brake type car is shown at 3. At 2 we havethe new constant mesh gear. They are shifted in theregular way by the driver, but in operation, instead ofactually shifting the relative position of the gears

in the gear box he merely shifts the keys fasteningthe gears to their shafts. This allows a perfect shifton hills since the gears are always in mesh. At 4we have the new hydraulic transmission. At 5 is

shown a new gear shift mounted on the steering wheel.The emergency brake terminates on the dash. Note

the ample space. -11. W. Secor.

GEARSHIFT

FOUR WHEELBRAISES

EMERGENBRAKE

IDEMOHSTRATITOK CAR 66 CUT RH aTAll,fr"

At the recent Paris Automobile Show an enterprising manufacturer, in order to show a full sized car cut completely in half. The car is shown above. Note that every parthis clients exactly how his wares are made and what they are made of, exhibited to view can be plainly seen. A good hint to American car exhibitors.

THE FIRST PRIZE WINNERS IN OUR $1,000 CONTEST

LT1121111.1111.,11,11,,,Lliontoriii..11m111/1.1111.111 wnaulumalutm.411.11.,,,Illt114,111111,11/11111.1:11111111111111110 ". HI. MI111.111/ IL111.11,1111111/111111111111111111..1,1.1,1M11111111111111L411111rj

are announced in this issue! Do not fail to read the list on page 856. Each month for the coming year this series of'prizes will be given for the best articles appearing in SCIENCE AND INVENTION. And nearly every article publishedwill receive one of them. The competition is open to everyone. It is only necessary for contestants to submit their ideaswith a short description accompanied by pencil sketches. Be sure to rush YOUR ARTICLE so you may win YOUR

PART OF THE $1,000.



10) /-Lc -9 -

One of the ,iinplest way, in e,nich to obtain butterfliesfor experimental purposes is to lure them with the aidof dried apples and valeric ether. It is only necessaryto hang the fruit, on which a little of the ether hasbeen sprinkled, on a convenient fence or twig. It willonly be a short time until the collector will have asmany of the insects as he can use.

After the butterflies have reached their full developmentand are ready for the final mounting, they sometimes be-come too dry for ease in handling. If such is the caseit is only necessary to put the dried insect on a smallplate shown above and then tomoisten the sand with a bit of water. It might benoted that when dry they become extremely brittle.

I t of the insect in thespace between the two boards and with the aid of pinsand strips of paper flatten the wings as shown above.For ease in handling the specimen it is best to thrusta pin through its abdomen, being careful not to disruptthe legs or the form of the body. By using this pin asa handle there will be many less mishaps.

When making decorative backgrounds with the aid of theinsects for such articles as serving trays or novelty dec-oration designs the well dried insects are placed on afoundation of evenly spread absorbent cotton. In orderto heighten the effect the cotton may be covered withsilk or other soft material. If the article to be deco-rated is a serving tray. the back is removed and the cot -

,r' rad evenly neer it.

In iai,ing butterflies and moths from the eggs laid bythe mother it is only necessary to find the twigs andleaves upon which the eggs are laid and then surroundthem with gauze or netting to protect them from theirnatural enemies, and to keep them from falling to theground as soon as they are hatched. Any variety oflight netting may be used.

After the insects have been plaza on the sand and ithas been moistened the whole is covered with a glasscontainer and allowed to set for a few hours. It is adangerous practice to handle the dried butterflies sincethey become so brittle that the slightest touch willshatter them. For this reason if there is ary sign ofdryness it is safest to dampen them.

After the h,,t, of paper have brought the wings intoplace pin them thoroughly to the board. A very conven-ient tool to use in this process is made by fixing a fineneedle into a wooden handle. This will help the opera-tor to move the fragile subjects with a great deal lessdanger to them. A fine pair of tweezers wir also hefound to lend ease to many operations.

After the foundation has been prepared, the dried speci-mens are removed directi from the box and with theaid of the tools described above are placed on the back-ground in the preconceived design. If the effect is tobe heightened milk -weed seeds and dried grasses and insome cases dried flowers may be used in connection withthe insects. It is best to mark out the location wherethe specimens are to appear 011 the completed design soas to do anon with a, much handling as

e..411ayS

In case it is found desirable to watch the developmentof the larva more closely, a small glass housing such asshown in the above photo may be constructed at a smallcost by the investigator in which the development ofthe eggs may take place. The housing should be con-structed so that the stems of the plant food suppliedthe insects may protrude into water.

The drying board for the final process is shown in theabove photo. It is made of two pieces of thin boardmounted so that they take the shape of a flattened "Y"with a small crack between them. The separation be-tween the two boards should be large enough to accom-modate the abdomen of the insects to be mounted.These boards may be made in any length desired.

After the peaces. of fixing the ,nef iniciis to the dryingboards is complete and all the pins and papers are foundto be tightly fixed to the board so that they will not beremoved by vibrations the whole is set away in a di,cool place for about three weeks. At the end of thisperiod it will be found that the specimens are thorough-ly dried and are in perfect shape for display.

Here is shown the completed design after the insects,the flowers and the seeds have been put in place on thebackground and the whole is placed under the glass of theserving tray. An infinite variety of designs may be putinto effect through this method and the complete prod-uct will have colors and a purity of design that anypainter might well envy since it is made of the naturalproduct of Nature.-Dr. Ernest Bade.


Science and Invention for January, 1924 S55

10 OWCIC AosuredHigh Frequency Induction Assures Radio Power Transmission.

By H. GERNSBACK

FrRENCH radio engineers have re.cently experimented with a new

sort of radio power. Our diagram4 shows how a substation wouldconvert the direct current into highfrequency alternating current which,in turn, would be led to an under-ground conductor resembling a

third rail, located three or fourinches below the level of the streetor road. Automobiles, (Figs. 1 and2), or a car as illustrated on ourcover and Fig. 14, would carry a

number of wire convolutions in whichthe energy from the undergroundconductor would be induced. Theelectric motors to drive the wheelswould derive their energy from thesestationary loops mounted under-neath the car. On the train shownin Flo. 3. the energy is taken fromthe overhead wire without a trol-ley being used. The energy is in-duced into a stationary wire on top FRSTENEOof the train. TO WHEELThe only draw -back to the scheme SHAFTheretofore was the use of tremend-

ous frequencies of 20,000 cycles persecond but with the advent of thevacuum tube (audion), it is nowpossible to solve the problem andFrench engineers who have con-structed models along this lineexpress themselves as satisfied withthe tests.The next step is to transform thehigh frequency current as inducedin the atuomobile coil to the orderof 15 to 50 periods per second.This result is obtained by meansof mercury vapor rectifiers. Regula-tion of the speed of the vehicle isaccomplished very simply by meansof a little self-induction coil ofseveral turns of copper wire woundinto a helix. This coil acts uponthe current as a faucet on water,passing more or less current. Futureautomobiles or cars of the typeshown will carry auxiliary storagebatteries for traveling away from theelectrified roads. We understandthat this system is to he tried outin France very shortly.

/4 A CONDUITSWIRE 2UP -ZnOvvr41

FORK

STATORCO/L

ROTOREAR/NG

3BUTTONMOTOR CON-TROL BOX

CURRENTCOLLECT OR

LOOP

N

INSULATORSUPPORTS

STEAM OR WATERPOWER CENTRALSTATION

CURRENTCOLLECTING

WIRE

T r

COLOREDLINE

HIGH VOLTAGFHIGH FREQUENCYWIRE IN CONDUIT

la

AUXILIARY STORAGEBATTERY FOR EMERGENCY

STORAGE

AUXESMAGE BATT. SWITCH

RECTIFIERE. SPEEDFREQUENCY CONTROLCONVERTER TR/MR/RNM.4 DIFFERENTIAL

GEAR

COPPER COLLECTORCOIL ON AUTO

HIGH VOLTAGE D.C.

OR LOW FREQUENCYA.C.

+-REAR WHEEL';

SUB -STATIONCONVERTS D.C.TOHIGH FREQ A.C.



Aw r s of 1000 Monthly 7rAzes.FIRST PRIZE $100.00

Name PageEdison Pettit 879

TWO PRIZES $50.00 EACHW. C. Kelly 863John W. Wells 868

TEN PRIZES OF $25.00 EACHDr. Ernest Bade 854Dr. Armin Demuth 864Dr. Armin Demuth 867I smar Ginsberg 869Dr. Alfred Gradenwitz 870Raymond Francis Yates 871Raymond B. Wailes 881Jack Kay 893W. L. Pearce 895Armstrong Perry 896

FIVE PRIZES OF $20.00 EACHPhil Gersdorf 851Dr. H. Becher 852Edwin Haynes 874Dr. Ernest Bade 883Ernest K. Chapin 884

TEN PRIZES OF $15.00 EACHW. E. Burton 851T. L. Walker 851Stanley Y. Beach 875L. B. Robbins 882C. R. Mullin 882Chas. D. Tenney 884Chas. Mohr 885L. B. Robbins 885J. T. Garver 885Geo. G. McVicker 885

TWENTY PRIZES OF $10 EACHG. A. Luers 882Mrs. Florence Swallow 886I. D. Burkett 886W. A. Kyle 886C. A. Oldroyd 886B. Williard 886J. N. Morrison 886G. A. Luers 887Nelson Edwards 887Chas. Vivier 931Carl Webb 932W. W. Johnson 933William Williams 933Guy Simmons 933David Kennedy 934Einar I. Rand 934Arthur Landman 935T. L. Stalker 936Chas. L. Higgins 941Edward W. Lens 943

TEN PRIZES OF $5.00 EACHHarry Cooper 931P. T. Reglade 932Walter Ridgwell 935Philip M. Zimmerman 935Maynard G. Columbe 936Jack Kay 938Warren Fleenor 93811,'," r,

$12,000 or More in GoldBeginning with the January issue,

SCIENCE AND INVENTION will pay$1,000.00 or more each month of the yearin prizes. Every article published in theregular news section will receive one ofthem.(The departments have awards of theirown which they will continue to give.)

Ideas are what the editors want. Theymust be told simply-so your mother orsister can understand them-in picturesand sketches. Be sure they are NEWand have something to do with science orinvention. The editors want pictures and

Above

ic.A.,,..-ed,,,4:age

atoll/C,Oel-Weed 7 VaCi/eczye;,,

ceps. 1923

tn." it°,:.;,t°SS Park Place.

Se York CItY*titer Ur. tonnbook:

I have roInolyear letter of Sept.23th, eat aloe,

the any, of the 'Re, sot.terse,. peruInn/Alen. ohloh I here

eed wIth ouch

think you havemade greet advanceby the nee of

ea Inoroamedounoer of plottingand In dIrsInlehne

the amount ofreadles natter.

une ere

treat oJorltrOfe111

no* Se able totand subjeotaohlob the,

would netstead If snobsubjects sere

dee4rIbed by the oldSettled.

I think youare 000duatteg rert, In.

trying ItterestIng esserlaent

and Metreyour bol OOOOO la

Tours very t

TA& p2a

THOMAS A. EDISON'S OPINIONis a letter received by SCIENCE AND INVENTION from the great inventor,giving his opinion on the new picturized magazine. It speaks for itself.

1,0.11111

Jason Crain 941H. N. Loeb 941Stephen Goff 942

TWENTY PRIZES OF $2.00 EACHE. RosewaterE. M. AbbotEdward L. FooteL. KranziJ. PhillyssA. FerrandJ. Arthur CalkinsC. W. Fancher

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88 monthly prizes will be givenfollows:

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I N Connection with our 512,000.00 prize contest announced last month, it goes without saying that you willI have to hustle to win a prize. The Editors do not wish to make it hard for you; quite the contrary. We wantthe pictures and want them badly. Herewith is reproduced our reporter's card. We shall be glad to send it toanyone who makes an application. By means of this card you will he able to secure entre into industrial plants,business houses, motion picture studios, steamships, mines, etc. This card will prove an open sesame to you inmany instances. Each card is numbered and only one is given to a correspondent. A postal card from you anda request for this reporter's card is all that is necessary for obtaining one. It will be sent you by return mail.Address Field Editor, SCIENCE AND INVENTION, 53 Park Place, New York City.

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937 Harry F. Gammeter937 John L. Kenickell937 Kenneth Kesterson939 L. B. Robbins939 Author Article, Variocoupler939 Bases940 Author Article, Increasing940 Capacities

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sketches-must have them-but ideas arewanted most of all.-And they will behandsomely paid for. The rules of thecontest will be found on page 534 of theOctober issue. If you haven't a copy, onewill be mailed you free on receipt of yourname and address. It will give full de-tails of the rules and hints on submittingarticles. The closing date for all prizecontributiOns will be the 15th of themonth preceding date of issue, i.e., 15th ofDecember for the February number; the15th of January for the March number,etc.

Science and CORRESPONDENT -...Invention IDREPORTERENTIFICATION

NO. 999THE BEARER OF THIS CARD_

IS AN AUTHORIZED CORR ONDENT . REPORTER OF

SCIENCE and INVENTION MAGAZINETHE - PUBLISHERS OF SCIENCE AND INVENTION WILLAPPRECIATE ANY COURTESY EXTENDED THEIR

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The Man on tI

Jdo not know where I was born. I amignorant of the country-I do not evenknow on which world it was. Theyare trying to tell me now that I wasborn here on Earth. That is absurd

And when you read what I have done, the

e MeteorBy RAY CUMMINGSThe night was calm without a breath of

air stirring Lucky for me for I wouldhave blown away had there been any wind!I sat there puzzling over my very existence. Iknew nothing, not even my own name. Ihave since named myself Nemo. They tell

Nona was in midair. Then, like a wasp she darted at that thing on the rock. The lizard-I shall call it that-saw hercoming. It leaped, and sailed across the cave. I saw that it had webbed membrane connecting its six outstretched legs.

Nona turned in the air after it, her slim body as sinuous as her waving hair.

extraordinary experiences I have undergone,you will realize that I am the product ofsome greater civilization than any you haveon this Earth. I doubt even that I wasborn on any planet of the Solar System.

I must be at least eighty years of agenow-as you on Earth measure time. I aman old man and my memory is full ofstrange lapses. There are blank periods inmy life for which I cannot account. Butyou will bear with me, I am sure.

I shall tell you my history exactly as Iremember it.

THE FIRST RECOLLECTIONII

The first recollection that I have waswhen I was a young man at the full heightof my physical strength. Let us say, I wastwenty, with dark hair and eyes, a slenderbody, but muscular and powerful. The dayI have in mind is clear to my memory now-but everything that happened to me beforeit is a blank. I found myself lying on theground. It was dark and there was a skyfull of stars and strange flashing lights.

I sat up, stiff and sore, and bruised allover. I was encased in some sort of arubber suit, with a pack on my back; myhead was enclosed in a helmet of transparent,rigid material.

I felt as though I were smothering; andI tore off the helmet and .flung it from me.I drank in a deep breath of the night air.It was pure and sweet, but heady. It mademy senses reel like some potent wine.

I say that I sat up. That is not strictlytrue. I pushed my elbow against the ground.and my whole body went into the, air. Ifloated back to a sitting posture. I waslight as a feather I

me there was once a famous sea captain bythat name here on Earth. I assure you thatis coincidence merely, for I have no connec-tion with your Earth other than that I amat this moment unfortunately imprisonedupon it. -

This place where I found myself thatstarry night showed a barren landscape withonly a few queerly -shaped stunted trees.The horizon was very close to me-almostat hand, in fact-for the ground was curved

. with an enormous convexity.

xdlet -

I saw her eyes once the mustles of my arms and >boulders, and her admiration pleased me. I stretched my arms for her,showed OEr the muiclei of my legs: and locked aoout for some way el displaying my pi owes>. There were many boulders

around that could be loosened. One by one I flung them into the air, sent them into Space never to return.

It was indeed, as though I were clingingto the top of a ball, whirling through Space.The stars were swinging across the sky withvisible movement.

I had been conscious no more than a min-ute when a moon swung up into view. Thenanother. And then, without warning, a mil-lion tiny worlds flashing silver with reflectedsunlight, burst up from below the horizonand swarmed the heavens. Behind them Isaw a tremendous, glowing silver sphere,with dark bands upon it-a sphere so largethat as it rose it almost filled the sky.

I want no mystery in my narrative; I haveno desire to puzzle you. I was on a tinymeteor-one of .the myriad that swarm incircular orbits about the planet Saturn andform its rings.

No doubt you are ignorant. Most Earth -people are, I find. Let me enlighten you f ur-

.ther.Saturn, in position outward from the Sun,

is the sixth major planet of the Solar Sys-tem. Its mean distance from the Sun is887,098,000 miles. It is a globe almost aslarge as Jupiter -74,163 miles in diameter,to be exact. It has, however, a trifle lessthan half Jupiter's density and only one-ninth the density of the Earth.

With Saturn's rings you are perhaps fa-miliar in a general way. They are concen-tric, and encircle the planet like a flat hat-brim-a brim more than 37,000 miles broad.These rings are, composed of billions uponbillions of tiny meteors revolving aboutSaturn all in almost the same plane andeach maintaining its separate orbit-each atiny satellite, each glowing silver from itsreflected sunlight.

And it was upon one of these tiny meteorsthat I found myself. Do not imagine thatI knew all these facts at the moment. Farfrom it. I had no knowledge of any kind.My body was developed to manhood but Iwas ignorant of everything with only instinctand a dawning reason to guide me.

I had tossed away my transparent helmet.It left my hand and went through the airlike a stone from a catapault. The last Isaw of it it was sailing out over a line oftrees.

My brain was still confused but I knew



that my body was over -warm. I took offthe rubber garment and pack, finding myselfin _a white knitted affair like a bathing suit-sleeveless shirt and trunks.

THE FIRST GLIMPSEI stood up unsteadily, and found that I

had just enough weight to maintain my foot-ing. My head was reeling, I suppose, largelybecause of the quality of the air.

Air, you say ! Air on a meteor like that!bo you call yourself an astronomer? If so,you show your ignorance by such questioning.Air, or at least something that served mypurposes of breathing, was there and thatI am here alive to tell it must be yourproof.

I could see perhaps a quarter of a mile.The land curved away, dropping down inevery direction so that the sky at the horizonshowed seemingly below the level of my feet.I was visibly on the top of the world.

Overhead those billions of tiny worldswere swarming. Sometimes fragments ofstar -dust would enter my atmosphere-flam-ing red shooting stars, burning themselvesout in an instant. And behind everythinghung that gigantic silver ball that was Sat-urn.

The whole firmament was swinging side-wise. In a few moments half of Saturn wasbelow my horizon. The Sun rose behind me-a smaller Sun than appears to you hereon Earth, but still the same yellow -red color.'

It was daylight, with the Sun mountingtoward the zenith so quickly in less than anhour it would be there, and my day wouldbe half over.

I saw myself now to be standing on aslight rise of black, sandy ground. Therewere metallic rocks lying about, a low, scantyvegetation in patches on the ground-vegeta-tion of a bluish color ; and flimsy, stuntedtrees. These had broad, angular blue -whitetrunks with spreading tops ten feet up, andfoliage that was bluish -white. Behind mewas a jagged, metallic peak perhaps a hun-dred feet in height.

There was no water in sight, no sign oflife of any kind. Quite suddenly I discov-ered that I was both hungry and thirsty.

What was I to do? This world was so

small I could have started walking in anydirection and come back to my starting pointin a very short time. Walking! It wasimpossible to walk! I weighed almost noth-ing. I stood teetering on tip -toe, straining

859

dred feet away and behind them, over thatdizzying curve downward of the world, wasthe azure of cloudless Space.

I was frightened, and now I know it waswith good reason. Had I leaped recklessly

The girl took light Her ams struck out, and like a swimmer mounting through water she boated up to the ceiling,landing upon a ledge of rock. Through a tangle of her hair her face peered down at me. And though her eyes were

frightened, there seemed an impish, mocking expression to her tremulous smile.

every muscle to maintain my balance, feel-ing like a balloon poised ready to sail away.

I make these speculations now. At thattime I had not the reasoning ability to specu-late. All I knew was that I was hungryand thirsty-with a hunger and thirst thatwas maddening. But was young andstrong, and youth fights.

I took a step forward. Under the impulseof my gentle leg -thrust, my body rose intothe air in a broad arc. I suppose I went upa hundred feet, sailing forward toward theline of trees at the horizon. I lost mybalance; my arms and legs were flying. Ifloated gently down and landed on my facenear the base of a tree!

You smile! I assure you it was not hum-orous to me. I stood up again, tremblingwith surprise and alarm. A new vista ofland beyond the former horizon had opened.I saw other little jagged peaks a few hun-

Nona watched int with awe, encouragingme with little syllables of .pleasure as I selected larger and larger rocks. SomeI dug up and tore loose, until at last I ripped off the top and side of a hill. It was a mountain of rock. I staggered

like Atlas.

into the air I might have left my tiny worldentirely-escaped from its slight gravitationsufficiently to become its satellite, or perhapseven completely to depart its vicinity andbecome a satellite of Saturn!

AN INHOSPITABLE WORLDThis tiny world upon which I found my-

self was inhospitable to the extreme; andyet if I had been conscious of the choice,I would not have wanted to abandon it forempty Space. Out there, worse than suf-fering hunger and thirst, I would not evenbe able to breathe. Thus, if you are ofphilosophical mind, you may find consolationin any unhappy plight. There is, indeed, al-ways something worse to contemplate.

Whatever my life before this day mayhave been walking evidently was part of it.I know that because my instinct was to walk.I decided to weigh myself down with rocksand thus be able to maintain a footing.Futile conception! I seized a huge rock ofblack metallic quartz in each hand-only tofind that the rocks themselves were merefeathers in my grasp! Angered I flung theminto the air. They sailed away, out overthe horizon. Undoubtedly they left myworld never to return.

The Sun was now past the zenith. It wasmid -afternoon. Shortly it would be nightagain.

I was clinging to the tree -trunk for sup-port, when quite near me I saw what seemedto be the mou:h of a cave. I was staringat it when a figure appeared from below.I did not move, and this thing evidently didnot see me.

It was a girl, fashioned in human formlike myself. She stood there cloaked in thelong waving masses of her golden hair. Imust have made some slight sound for aftera moment she -looked my way. I caught aglimpse of a beautiful oval face framed inthe golden tresses, lips full and red, eyesblue, wide now with fear.

Without warning, she left the ground.She went swiftly past me, lying in the airgracefully on one side, her arms movingrhythmically. She was swimming in the airwith all the grace and skill of a mermaid!

I stood spellbound. In a moment she hadpassed over the curve of the world anddisappeared.

III

Can I say that the sight of this girl in -(Continued on page 904)



Doctor Hacliensaw's SecretsBy CLEMENT FEZANDIi

MAN has conquered the earth and theair. There still remains, however, thevast unexplored regions at the bottom

of the ocean, that haze so far eluded his do-minion. Yet they must contain untold treas-ures in mineral wealth, coal and petroleum.This story of a submarine city, which seemsa wild fantasy today will be a cold fact inthe not distant future.

No. 25The Secret of theSubmarine City

this submerged land is more than I canfathom. The only thing I see that might bemade useful are the fish."

Five minutes later the hydroplane had alighted on the surface of the ocean. Then it came to a complete stop, and alarge yawning metal mouth came sio out of the depths of the water and closed over it. Then it was dragged downinto the ocean by means of a cable. Again there was a halt, followed by a click. "We are now in one of the receiv-

ing compartments," explained Doctor Hackensaw.

" ILAS," said Doctor Hackensaw, im-pressively, "I'm going to initiate youtoday into one of my greatest secrets-one that I have so far revealed onlyto those whose co-operation was

necessary to carry out my plans. Silas, Iam a king !"

"What!" cried the reporter, gazing at thedoctor in amazement, and wondering if hehad suddenly gone mad. "What did yousay?"

"I said I was a king, and it is true. Iam the supreme ruler of a large country-in fact I am really monarch of a domainlarger than all the other kingdoms on earthput together."

"What in the name of the Seven Won-ders do you mean?" asked Silas, perplexed."Have you discovered a new continent in thePolar regions?"

"No," replied the doctor, "but I havefound the means of conquering and bringingunder my dominion immense unexploredregions in the ocean's depths. For years ithas seemed to me foolish that man, over-crowded as he is on land, should allow theenormous tracts under water to remain un-used. Do you realize, Silas, that the oceancovers far more land than all our four con-tinents put together? It is this land that Ihave sought to make use of-these submerg-ed tracts that so far have. been allowed toremain idle, and that are yet capable of pro-ducing immense wealth, and of supporting apopulation greater than that now in exist-ence. I have no competitors. My secret hasbeen well kept, and I am absolute mon-arch of my own dominions. I make my ownlaws and I enforce them myself."

Silas Rockett looked puzzled. "Please ex-plain yourself, doctor," said he. "I gatheryour idea in a vague way; but not veryclearly. I suppose you have explored aportion of the ocean's depths with submar-ines, but how you can make any real use of

"The fish, of course," returned DoctorHackensaw, "are of great importance-Ihave my submarine fisheries and my sub-marine flocks if I may so call the immenseschools of fish and marine animals thatI keep penned up. The returns are highlyprofitable. I learn the fishes' habit andtheir habitats. I place immense traps at theproper places, bait them carefully and securethouands of tons of fish with very littletrouble. My canning factories run nightand day. The fish are cleaned, cooked andpacked by machinery, while absolutely fresh,and so have a flavor unequalled by the or-dinary commercial grades."

"You have flocks of fish, too?"

"Here are Perfectspecimens of all kindsof marine plants andanimals, specimens suchas you will not find inany museum on earth,for my men go out indiving suits and selectonly the finest speci-mens. My workers arefree to move about asthey use my artificialpills to furnish themair for breathing. Thenhere are relics fromsunken ships. Thesecoins and jewels camefrom a Roman galleythat sank here hun-dreds of years ago,and was deeply imbed-ded in the silt. Wecome across very curl-

om things here."

SUBMARINE FARMS

"Yes, domestic herds. I hatch fish fromthe spawn and keep them penned in suitableplaces. Then, too. I have my submarinefarms. You probably know that many sub-marine animal and vegetable growths have areal commercial value. Iodine and bromineexist in quantities in certain sea weeds andcan be extracted with profit. Then I havewhole acres planted with sponges of thefinest quality-my oyster farms cover milesof surface and I even raise the pearl oystersand can produce pearls of the largest sizeand most wonderful lustre. You see. Ihave scoured the world to secure the beststock."

"But who attends to these submarinefarms ?"

"I have no lack of help. My submarinecities have a large population-not only self-supporting but every member certain of be-coming wealthy in the course of a very fewyears."

"Submarine cities?" cried Silas, more andmore perplexed. Am I to understand thatyou have found means of enabling men tolive and work in the ocean depths, and thatyou have found men willing to so live?"

"Yes to both questions. Silas. Yes, Ihave found means of enabling men to liveindefinitely under water in perfect comfort,and I have had no trouble in finding menand women willing to work for me. Un-fortunately there is still a great deal of mis-ery in the world, and men and women gladlycome to me to escape from it. Then thereare enthusiastic young people in search ofadventure, and they form the elite of myworkers. The inducements I offer are great-for I guarantee to all my workers whoremain a few years with me, a comfortablepension for the rest of their lives. But, ifyou are to understand the matter, I wouldbetter begin my story at the beginning-What first gave me my idea of a submarinecity, was the study of the gasoline problem."

HOW THE DOCTOR STARTED

"Gasoline?" echoed Silas Rockett."Yes. With the increasing use of gasoline

fuel-oil for automobiles, aeroplanes andships the supply of petroleum is certain verysoon to become inadequate. The conse-


Science ant! Invention for January, 1924

quence will be a great rise in the price ofgasoline and the need of some substitute.During the World War a number of substi-tutes were tried with more or less success.Alcohol gives good results and can be madein laige quantities. Hydrogen gas was tried,the automobile carrying a balloon of this gas.But the scheme was not found very prac-tical. Liquified hydrogen in tanks mightanswer' better. Electricity will some daysupersede gasoline, but not for some timeyet. I resolved to turn my attention first toincreasing the available supply of gasoline.Gasoline, as you know, is made from petrol-eum, and the petroleum is found deep underground.' In fact, petroleum is a by-productin the natural formation of coal. The liquidsinks from the coal -beds deep into theground, forming underground pools. Theseare often under pressure, and when tappedwill spout up above ground like artesianwells.

"Such being the case, and England posses-sing very rich coal mines, how was it thatEngland had no oil wells? Petroleum mustexist in Great Britain in large quantities-why was it not made use of ? I found theanswer in a London Museum, where I wasshown samples of petroleum obtained byborings made in different parts of England.But this petroleum, probably owing to thechalky nature of the soil, was deep underground, and could not be profitably util-ized at present.

OIL BENEATH THE SEA"I consulted several distinguished geolo-

gists, carefully studied the geological maps,and became convinced that there must existlarge deposits of petroleum below the bot-tom of the North Sea. The question thenarose as to how to dig an oil well underwater. The answer was obvious. We mustsink one or more caissons and work fromthese. There was nothing new in the method-it is used daily in building bridges.

"I began by sinking two caissons andjoined these together by a tunnel which Iexcavated deep under the sea bottom. Thistunnel was gradually enlarged in spots toform large chambers. One of these servedfor the drilling operations and the othersformed store -rooms and sleeping rooms.

"The great trouble was to keep matterssecret. To achieve this, I bought an Eng-

lish power plant. Conducted the electricalpower to the work by cables. The air sup-ply is obtained from above by means ofextensible conduits. A ship of my own onwatch informs me of the approach of strangevessels and my air -pipes are then pulled

861

saw in England. about to embark in oneof the doctor's hydro -aeroplanes for a visitto the secret under -water city.

The aeroplane was in good condition, anda thirty -minute flight brought the two menout over the North Sea.

While Silas and the doctor were waiting for their turn to pass through the door, the doctor showed the reporter an irongrating through which the ocean water was descending into an unused mine -shaft.

down below the surface, and compressed air,stored in reservoirs, is used until the strangerhas passed. I obtained my water supply, ason shipboard, by distilling the sea -water. Iexpect soon, however, to obtain an amplesupply of fresh water by means of artesianwells. But what's the use of talking! Youhave a month's vacation. I am sailing forEngland tomorrow. Come along with mefor a visit to my submarine city, and Ipromise you that you will be well repaid foryour trouble."

And that is how, some days later, SilasRockett found himself with Doctor Hacken-

At this momenta shriek from the woman with the baby called their attention to the fact that the mother burdened withthe child had been unable to provide herself with life preservers or helmets. It was only with the greatest difficulty that

Silas and the doctor managed to secure helmets for the two, and get the pair safely protected.

"We are now somewhere near Submarina,as I call the city." said the doctor, "so I willwireless the radio station to notify them ofour arrival." Sitting down to his machine,he sent off alarief message and received theanswer.

"All right," said he. "They say they willpilot us to our destination. See. The com-pass is turning to point the way."

Silas looked at the instrument indicated.It was different from any compass he hades er seen. It was a needle suspended on auniversal joint, and it was surrounded by anumber of electro-magnets, each designed tobe rendered active only by a radio -waveof a special length. The operator in Sub -marina could thus turn the compass needleon the aeroplane in any direction he desired.The needle had now assumed a sloping di-rection, and the pilot of the aeroplane turnedthe machine in the same direction.

"We shall soon be in port, now," remarkedDoctor Hackensaw.

"But what's the use of this guiding instru-ment?" asked Silas.

TO SUBMARINA"This arrangement is absolutely necessary

at present," replied the doctor, "because, as Itold you, I am keeping the existence of thissubmarine city a complete secret. I myselfcould scarcely hope to find it, in this wasteof water, without some guide."

Five minutes later the hydroplane hadalighted on the surface of the ocean. Thenit came to a complete stop, and a large yawn-ing metal mouth came up out of the depthsof the water and closed over it. Then it wasdragged down into the ocean by means of acable. Again there was a halt, followed bya click.

"We are now in one of the receiving com-partments," expained Doctor Hackensaw."This receiving chamber has closed over us,and we must wait until the water has beenpumped out before we can emerge."

The pumping out did not take long. Themetal mouth that enclosed them opened, and

(Continued on page 910)


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in th

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.T

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for

the

priv

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kee

p th

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out

and

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he le

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com

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fairl

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r ca

ps.

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m.

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arm

y of

spi

es to

wee

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t the

cam

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ho m

ight

slip

in a

t the

gat

e.T

hey

rent

ed a

ll th

e ho

uses

aro

und

the

cour

se w

here

thei

rri

vals

mig

ht s

et u

p ca

mer

as w

ith lo

ng d

ista

nce

lens

es a

ndev

en h

ired

a c

oupl

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airp

lane

s to

pat

rol o

ver

the

race

cou

rse.

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n th

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ent a

pai

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mir

rors

arou

nd th

e re

ar o

f th

e co

urse

and

fla

shed

ligh

t bea

ms

alon

g th

e ra

il of

the

gran

d-st

and

in o

rder

to b

lind

any

disg

uise

d pi

ctur

e -t

aker

s'ca

mer

as. T

hey

even

pro

tect

edth

e co

urse

with

sm

oke

pots

, giv

ing

off

grea

t clo

uds

of o

paqu

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they

wer

e ou

twitt

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ven

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two

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ne c

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ired

two

mov

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ctre

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with

cam

eras

hid

inva

nity

cas

es.


Science and Invention for January-, 1924 863

"Sure Thin S At the County FairMethods of the "Con Men" for Parting the Yokel and His Money

BY W. C. KELLY.

The little game played with thearrow spinning around over a listof numbers is known to every onewho ever attended a street fair.It looks honest-and so do a lotof hold-up men. The trick issimple. By pressing an incon-spicuous nail head at the end ofthe table the operator works abrake on the whirling arrow stop-ping it approximately where he

wants it. These games are oftenworked with a confederate.

Here the fish puts the marble in one of thetwo hohs at the top of the case and it fallstown though a set of pins fivally falling intoone of the holes at the base of the contraption.The oplirator moves the baseboard slightly,making the marble fall into one of the slotsbearing a useless Orion.

This gambling device is one of those in

which the arrow flips against a number ofbent wires. The wires are stout a quarterof an inch thick and can be turned in theirsockets. The operator can turn the wiresand tell you long before the wheel spins ifit will stop on odd or even.

This arrow game ispracti,ally the sameone as described above.It ha! the bent wiresagainst which the arrowruns. The player is al-lowed to spin the indi-cator and the indicatorwill stop in the correctpositien no matterwhich way the spin ismade.

eMLILit\ \obi -.

sr'

rThis one is on the same order hotslightly more refined. The crookmust know his business a littlebetter to operate it. The arrowsets on a spindle that can bemoved about over tire table top,giving the tiling a quite innocentair. The secret is in setting thearrow. There are two s m allbumps. one on the arrow and oneen the spindle that stops the arrowat the right place.

Almost identical with the firstarrow game is this one sup-ported on three legs and stand-ing above the table. The brakeon the wheel's motion is sup-

plied by a rod running upthrough one of the legs of thesupport. A lever connectingthis rod runs through the table ""in the same manner as the ar-row brake, so that the oper-ator only presses the nail.

How many dollars have gone the way of all theearth through this clever piece of palming! Itis all very simple and now most everyone knowsit. But what a history it has had in the annalsof the "sure thing" man! The trick is simple.The operator simply palms the pea after showingyou that it is under one of the shells. He then,by the same method, puts it under another andtakes your money.

"Take any Jack, King a n dQueen," the barker says-buthe doesn't. He takes a Queenand Jack and another cardwith a Jack on one end and aKing on the other. He turnsthem face down, shuffles them,and asks you to indicate theKing. You do. But his thumbcovers the King mark and theJack shows.

The three colors are arrangedfor betting. Then when thebets are down Are red, fivewhite and five blue balls areplaced in the dealing box witha striped ball, the "housepercentage." One of the col-ored balls rolls out. The betsire paid. A switch connectedto two electro-magnets at thehoz outlet is closed. Theseattract the striped ball be-cause it is the only iron one.

Many cigar stores and pool rooms have aboard where dice are thrown for cigars.Notice that beneath the glass of the show-case there is what appears to be an in-nocent _humidor. Usually six dice are

used., The winnings are figured on thetotal number of points thrown. The se-

cret is that the humidor contains a power-ful magnet and that one side of the diceare loaded. Thus if the total shows signsof becoming too high the operator has

only to connect the magnet, taking the"chance" out of the game.

The bottle pool gamsisn t so well known.It takes some bit ofdexterity for operationand is very easily de-

tected. Two whiteballs and a black oneare placed in the bottle.All are numbered. Thesuckers bet on which ofthe three balls will rollout of the bottle. Thelittle hold -out arrange-ment in the side of thebottle, which is madeof leather, is very easilyoperated by a slightpressure or. the side ofthe bottle.


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of 1

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se a

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e id

eas

of o

ne o

f the

fore

mos

t rai

lroad

eng

inee

ring

auth

oriti

es in

the

coun

try.

Asi

de fr

om th

ead

vanc

emen

ts th

at w

ill b

e m

ade

in th

e lu

xurie

s th

at w

ill a

ccom

pany

trav

el, t

here

will

be

grea

t str

ides

take

n in

the

The

re is

no

end

to th

e ta

les

of g

reat

adv

ance

men

t mad

e in

the

auto

mot

ive

and

airp

lane

spee

d re

cord

s.B

ut li

ttle

is h

eard

abo

ut th

e ad

vanc

emen

t mad

e by

the

railr

oads

. No

less

an a

utho

rity

than

F. H

. Har

din,

Chi

ef E

ngin

eer

of M

otiv

e Po

wer

and

Rol

ling

Stoc

k of

the

New

Yor

k C

entr

al R

ailr

oad,

com

es f

orw

ard

with

the

anno

unce

men

t tha

t the

nex

ttw

enty

-fiv

e ye

ars

will

see

the

grea

test

adv

ance

men

t in

the

fiel

d of

rai

lroa

den

gine

erin

g.-I

f w

ater

pow

er is

dev

elop

ed to

the

exte

nt w

here

ele

ctri

cal

pow

er c

an b

e bo

ught

che

aply

'eno

ugh,

we

may

look

for

the

com

plet

e el

ectr

ific

atio

n of

the

railr

oads

. With

the

wid

enin

g(o

f th

e cu

rves

long

er c

ars

will

com

e in

to u

se a

nd th

e tr

ains

pulle

d w

ill h

e lo

nger

.A

lso,

radi

o w

ill c

ome

into

use

on

long

fre

ight

trai

ns.

At t

he p

rese

nt ti

me

som

e tr

ains

are

mor

eIt

lihn

a m

ile in

leng

th a

nd w

ith th

e co

nsta

nt p

erfe

ctio

n of

the

loco

mot

ive

it is

entir

ely

pos-

sibl

e th

at in

the

next

twen

ty-f

ive

year

s w

em

ay lo

ok f

or f

reig

ht tr

ains

two

mile

s in

leng

th.

The

y m

ay b

e eq

uipp

ed w

ith r

adio

at b

oth

ends

so

that

the

two

part

s of

the

crew

may

be

dire

ctio

n of

spe

ed a

nd s

afet

y.M

ore

atte

ntio

nIs

giv

en to

the

safe

ty o

f the

rai

lroad

trav

eler

than

is g

iven

to th

ose

trav

elin

g by

any

oth

er m

eans

.T

houg

h sp

eed

may

be

mat

eria

lly in

crea

sed

itw

ill a

lway

s be

sec

onda

ry to

the

safe

tyof

the

pass

enge

rs.

cons

tant

ly in

touc

h w

ith e

ach

othe

r. O

ne o

f th

e ch

ief

fiel

ds f

or a

dvan

cem

ent,

says

Mr.

Har

din,

is in

the

fiel

d of

sig

nals

and

saf

ety

devi

ces.

Con

stan

t exp

erim

ents

are

bei

ng m

ade

to r

emov

e th

e hu

man

ele

men

t in

oper

atio

n as

far

as

poss

ible

.T

his

will

be

done

by

som

efo

rm o

f el

ectr

ical

equ

ipm

ent t

hat w

ill e

nabl

e th

e de

spat

cher

in th

e si

gnal

tow

er to

stop

the

trai

n w

ithou

t the

ass

ista

nce

of th

e en

gine

er in

the

cab.

It is

als

o po

ssib

le th

at a

ll lo

ngdi

stan

ce p

asse

nger

trai

ns o

f th

e fu

ture

will

he

equi

pped

with

rad

io s

o th

at th

epa

ssen

gers

may

kee

pin

,to

uch

with

thei

rho

mes

and

offi

ces

all

the

time.

Gra

de c

ross

-in

gs w

ill b

e re

mov

ed a

nd a

ll gr

ades

in th

e lin

e w

ill b

e re

duce

d to

thre

e pe

r ce

nt.

At p

res-

ent,

man

y of

the

fast

trai

ns h

ave

to r

un in

sec

tions

nec

essi

tatin

g an

eng

ine

and

crew

for

each

sec

tion

ther

eby

incr

easi

ng th

e op

erat

ing

cost

s.W

ith th

e im

prov

emen

ts in

the

road

bed,

long

er a

nd la

rger

car

s m

ay b

e us

ed d

oing

aw

ay w

ith th

is in

effi

cien

cy:

Car

s eq

uipp

edfo

r m

ovie

s, r

adio

con

cert

s an

d va

udev

ille

will

be

the

regu

lar

serv

ice

on th

e fa

ster

trai

ns.

00 ON

ON

ef



Million To Meteorite FoundDRILLING RIG,.4 DIAMETER % MILE

THE CRATER TODAY AVERAGEDEPTH 570 FE ET

_ti&

ORIGINAL BOTTOM OF BORECRATER 1150 FEET DEEP 1400 FEE Ty,

THE METEORITE

160 FEETABOVE PLAIN

OR POSSIBLY 4 TIMESBE 300 FEET IN DIAMETERSMETEORITE THOUGHT TO

THAT SIZE, WEIGHT "ergo.,1,000,000 TONS

A mining company has just started prospect drilling in Canyon Diabolo, Arizona, in an with which it fell from the sky made the crater shown in the sketch. 'It is four -fifthsattempt to discover the dimensions of a meteorite buried 1,400 feet underground whiff of a mile in diameter and originally went to the depth of 1,150 tett. The Navajo Indianscontains 90 per cent pure iron, 8 per cent nickel and quantities of platinum. The toile deify the meteorite. Its value is estimated at $15.000,000.

Small Turbine Drives Huge Generator

LOWPRESSURETURBINE

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HIGHPRESSURETURBINE

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GENERATOR

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At first the small engine driving the electrical generator seems ridiculously inadequate. lb. per sq. in. steam pressure) turbine is coupled to the low pressure turbine, which latterBut the engine actually develops one thousand horse -power. The new high pressure (LOW makes use of the exhaust steam. Both are connected through gears.-Dr. A. Demuth.



Graphic Depiction of the Rise of Man from the Anthropoid ApeBY DR. 0. HAUSER

Chart of the Developm.-nt I Man

S.i.ii5inning with the close ofthe Tertiary period (whichto the present time hascontributed no fossilized re-mains or evidence of man)this chart, translated byDr. Alfred Gradenvoitz,shows the various stapes ofthe development of thePithecanthropus (which wasnot of the species Homo noryet Anthropoid Ape) downthrough the beginnings ofthe Quartenary period anddown to the present time.

(NAGDALENIENSOLUTRE'ENAURIGNACIEN

THIRD GLACIALPERIOD

040uSTE'RIENACHEULEEN

01925 BY SCIENCE AND INVENTION



Huge Wind " ewer SystemCambridge University Professor Submits Plan to Harness Wind.

FEEDERS

LIQUIFIER4-

ELECTRICMOTOR

SUPPLY

U LE -WALEGAS STORAGE TAM

1. UNDERGROUND)

6t41.i.

AIRCOMPRESSOR

WATER DRIVENPUMP

FEED PIPE TOGENERATING

PLANT

LIQUID GASPRE -HEATER

BY RAYMOND FRANCIS YATES

WINDDRIVENDYNAMO

WATER ELECTROLYTI CALLvSPLIT UP INTO u

AND

FEEDERS

WIND DRIVEN iGENERATORS

- I I

1

WITH the ever increasing demands madeon the natural resources that are used

to develop energy, by the constant enlargingof the scope of industry, all technical men aresearching for new fields of energy production.Professor J. B. S. Haldane, of CambridgeUniversity, England, has designed the powersystem shown here. He would erect a largenumber of small wind -mills which would becoupled to small generators. To care for thegreat fluctuations in the demand for power,the scheme includes a system using the elec-tric current generated to break up water intoits component parts and then liquifying thetwo gases, hydrogen and oxygen. These gasescould be stored in huge vacuum -lined, under-ground tanks and their stored energy usedwhen the current demand became too greatfor the wind -mills to carry. These would alsoserve to furnish power during quiescence ofthe wind. The power of these gases is usedthrough the medium of internal combustion en-gines coupled to a generator. Oxygen and hy-drogen mixed in certain relations form a veryexplosive compound. They form one of themost perfect fuels known. Plants would beerected in all parts of the country and con-nected by means of high tension transmissionlines. Great waste spaces that are now put tono other use could be utilized for the erectionof the power stations. Even the tops of hillsand cliffs could be used for this purpose.

- -ELECTRIC

SWITCHBOARD

1

11,1/

LIQUID GAS A. C.DYNAMO

TURBINE

ELECTRIC, PO ER'TO HOMES WAINDUSTRIES

(01923 BY SCIENCE aINVENTION



A !Edon Volts Un r Control!Experiments In Home-made Lightning Flashes

It is hard to vizualize lilt actual sire of the spark shown in the abovepicture, made in one of the experiments at the high potential laboratoryof the Westinghouse Electric and Manufacturing Co. The spark hereliberated is more than twenty feet in length and represents 850,000volts. This spark, representing literally thousands of horse -power, wasused in testing the dielectric value of an insulator. The insulator wasplaced in the transmission line from the high potential transformer andthe voltage gradually raised until the current became snore than theinsulator could stand, which was indicated by the spark jumping acrossthe terminals to the conductor at the other end of the insulator

A forty-two foot controlled arc! It hardly seems necessary to add that this is

the longest controlled arc ever made. One million volts transmitted to the endsof the conductors between which the arc occurred was necessary to produce thisarc. It was drawn in tests for "Wet Flashover," which is a test applied to theconditions under which high tension lines must operate in rainy weather. Accu-rate comparison of the hugeness of this discharge may be gained by comparingthe thickness of the flash as well as its length with the size of two men shownstanding in the photograph. The arc was held under perfect control.

Interior of the high -voltage laboratory of the Westinghouse Electric andManufacturing Co.. at Trafford City, Pa. The huge million -volt transformercan be seen in the right of the photo. This is the only transformer of thekind in the world. A good idea of the size of the apparatus used in theexperiments with the so-called artificial lightning can be pained by compar-ing the size of the man standing by the huge spark gap shown in the extremeright of the picture. A traveling crane has to be used in the building formoving the various pieces of apparatus from one part of the laboratory toanother. An even larger gap can be seen just beyond the smaller one. One

puint pap is supported from the ceiling by the huge steel frame -workof the building while the other is mounted on a treat insulating pillar. The

noise of the sparks released by the high potential currents is deafening.

This photograph is another flashy:veer test made in the laboratory. It reread800,000 volts gone on the rampage. In taking this photograph a series ofquartz lenses were used, thus bringing into prominence the ultra -violet rayswhich would not be recorded using the common method of making the photo-graph. By this method the flare -out at the top of the spark column is shownthat would otherwise be invisible. The spark here, as in the first picture,is breaking over the capacity of an insulator. With the use of the ultra-high voltages used in the laboratory the engineers of the company are able

to ascertain with almost exact certainty just how any piece of high tensionapparatus is going to work when it is put into actual operation and just whatits limit of strength is. Experiments are constantly being carried on

looking toward ultra -Iona distance transmission of power service.

.1.11.11111M1111.111.1W



$RO Toy Cont

MERCURY

First prize, $25, goes toW. C. Michel, for GolfGame. Numbered corkdisks are to be placed onnumbered circles with a

drop of mercury.

CONTACT

EIECTRO MAGNETS

Fourth prize, $10, is paid to Jerry Sehnontka, for the automatic see -saw shown at the left above. Magnet pole -pieces make contact.Fifth prize, $5, goes to Walter Markowski, for the paddle wheel oil can steam engine shown center above. The oil can acts as aboiler; spout directs steam against tin paddles. Sixth prize, $5 to Franklin Cathell for the miniature steam shovel (right, above),constructed of scrap tin and wood. The shovel is operated by the wise windlasses seen protruding from the sides.

rkze WhcAneTraResults of Contest Announced in October Issue.

ARMS PIVOTEDTO BODY

BODY "PIVOTEDTO LEFT LEG WHICH 15STATIONARY AND SECUREDALFOOTTABT0 BASE

5 OT

DEPRESSION

SCREWEYE

NUMBEREDSPOTS Second prize, $20 to RUBBE

NUMBERED CORK, W. S. Hendren forDISCS foot ball kicker as

shown.

0 --RIGHT_FA.51=10 BODY

_RIGHT LEG AND LEVER_ALLAN _ofsE PIECE EX-TENDING DOWN THROWNSLOT 50 A TO GIVE No

A SWINGI5 NGMOVEMENTLEVER.

SOFT IRONARMATURE

-7;Ivo10°OAR. BOA

TINSUPPORTS

STEASCREWTOP

WIRESUPPORT TO

CAN

TIN WHEELf-CORK PULLEY

E-10-0 WiFtE NAIL.SOLDER TO_NAIL.

BAND

OX

VINESTRING

COIL OF WIREwOUND

AROUND GLASSTUBE AI MI3+5

0CONCEALEDWIRING

DOTTED UNESHOWINGPOSITION OF

COILKEY

GLASS Third prize, $15,(ONNE1'"BE taken by A. Melvin

WIRES L y IRON Skellett, Solenoid andPLUNGER iron plunger in doll

OTTON FOR shift weight so dollSEAT PLUNGEIZTO swings when key is

FALL ON pressed.

01111(10SOLENOID 11110/

IRON COREMP IJ...1.03

REVERSELEVER.

CRANKSHAFT

Seventh prize, $5, is awarded to Alfred Clark for the electric engine shown at the left. It is motivated by an iron core running in a solenoid which is magnetized

by the contact of the fly -wheel axle against a brush wire. The eighth prize, also $5, goes for the submarine diver, (center; above), which is actuated by rubber

bands. Diving planes, propeller and rudder are of tin. Ninth prize, of $2, is given to Mrs. Erwin, for the roach operated toy shown at the right. A small card -board

box, three inches in diameter, is covered with a piece of cardboard on which short paper extensions have been glued as shown. The don is fastened with a pin to thetop. The roaches moving in the box cause the doll to spin.

rURN TABLE BUCKET

PASTE BOARDDOLL

PIN

PASTE BOARDSTRIPS

7 7PROPELLER

RUDDER DIVING PLANES -\R.VESSER BANDS

METALSTRIPS

10-

0 ERECTORkV NEELS

RUBBER BAND

ROBBER2AND

NAIL

ROACHES

SAND-333NTAINERrC TH

CLIP

WIRE PIVOT

NVI1G.HT

The tenth prize, $2, is awarded to Lawrence Benson for the rubber band gun. When fired the band flies off its barrel. The eleventh prize, $2 goes to Roy Hale,for the alarm -clock tractor. The twelfth prize, $2, is given to Casimir Mazur for the sand -operated fan mill as shown. The thirteenth prize, $2 is awarded to AdolphF. Lank, for the swinging "Kiddie Horse" (right, above). The horses' heads are cut out and set on wire pivots. The counterweighted wires cause the horses to swing.



New Deakgn.f ReveicaAb_c TuaIDA.me

ABOVE at the left will be seen aa completed model of the reversi-ble steam turbine invented by Mr.Bonom. The gentleman in the photo-graph is holding two of the rotorsand one of the separating rings. Itwill be noticed that the two rotorshave their blades set at different an-gles so that with steam passingthrough them in the same direction,the two rotors are revolving in oppo-site directions. This is what takesplace continuously in the turbine, thecompensating gears transmitting thepower to the shaft so that it revolvesin the same direction, even thoughthe rotors are revolving in different

ways.

.31=11l111111111.11111111111111111111,1111111.i.lii111111.0...

Rotors Running in Opposite Directions Are Geared to Shaft.

PINION FORINSIDE SHAFT

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PINION FOROUTSIDE SHAFT p.mizimasm

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EQUALIZINGPINIONS

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OMMMMIMM\, ENGAGINGOimd GEAR

DRUMS REVOLVING IN OPPOSITE DIRECTIONSAND FASTENED 10 INNER AND OUTER SHAFTS.

REVERSINGLEVER

GEARS FASTENED/TO SHAFTS

PULLS,

1111111111111111111r1111111.1111111,11,1.1111111,...1.111111711711,111,111111,111

THE above photograph is a close-up view of the two rotors used in

the reversible steam turbine. Notethe angles of the blades. At theleft is a simplified view of the dif-ferent parts of this reversible tur-bine. Note how the two rotors re-volve in opposite directions and howthey are neared to the main shaft bymeans of beveled gears and a hollowand a solid shaft. By means of onesliding gear connected to a handle atthe extreme right, the direction of therotation of the pulley may be changedat will without stonoino the turbineor changing the direction of the ro-tation of the hlades. This is sim-ilar to an ordinary reversing device,the novelty lying in the rotors travel-

ing in opposite directions.

Unique UniverazL Letter Sign

i ii"ie

By slotting a solid background and fitting it with shutters to cover theslots the unique universal sign, shown above, is made. The shutters andthe background being of the same color, when the shutters are closed thesign face presents a solid appearance. The letters are made by turning the

Above are shown samples of the same letter which may be made with thenew advertising device. At the extreme right is shown the method of mov-ing the shutters. The whole thing is made of a light grade 'of sheet steeland when once in place is little trouble to the advertiser. The inventor.

74

"V41 Ya4

11.

shutters one -eighth turn on their pivots which permits light to shinethrough the slots making the letters. Any design may be executed on theboard. The shutters are light and require only a touch of the finger tomove them, making the changing of the sign a very small bit o work.

v VsoAA I A

vvAA

v

avv, a.

7,7711, V

AAILIAAAAv I IIVITAAAAAAA

Rowland N. Chubb, of Los Angeles, made the original model of cardboardcarving all the parts with the aid of a pocket knife and a pair of scissors.The shutters are fitted with a small wing on one side which is used toopen them. -Edwin Haynes.


Science and Invention for innw:ry, 1924 875

YalrileT, BeeTeem and Kfitchenette

A new complex apartment recently opened in Newark. N. J.The apartments consist of one large room, a small foyer,dressing alcove and bath. The large room becomes living

room, bedroom, kitchen and dining room with a few twists ofthe wrist. The beds fold from doors, at night.

The kitchen in the apartment. Curtainsare drawn in front of it when it isn't inuse. It has stove, ice -box and sink with

hot and cold water.

- `MX10111110M - -

LOOK PLAN

7.6

:IiiVierieVa'aVeleeireianiania'aViedVaVaneeaWeaVANIVWaNNVie s'AIWAVEWVa'amemmamaVameale":*

Norizonta

Both the roomsshown here are thesame. To the left is

the living room whenthe tenants are readyto retire. In themorning it becomes

again the charmingliving room seen atthe right. The li-brary table, by sim-ply pulling a leverconcealed beneath it,becomes a diningtable. The telephoneconnects through a

baseboard plug.

Eneficatelr foi PlanetsBy STANLEY Y. BEACH

TO WIND DRIVEN DYNAMO

ELECTRICLAMP

LE NS

GEAR

GROUND GLASSDIAL ,,,,,

OF LIGHT\BRIGHT SPOT

PIVOT RELEASESCREW

WIND DRIVENDYNAMO

One of the greatest dangers to aeroplane pilots is thetotal loss of sense of direction. A ray of light froma wind driven dynamo strikes the surface of the mirrorwhich forms the top of a miniature gyroscope. Thebeam reflected on the ground glass shield tells theaviator of his angle with regard to the horizontal.The gyroscope is started by means of a small tubeconducting air from the edge of the fusilage againstsmall notches cut into the periphery of the gyro.

scope wheel.



"Cigar Box" Conteat--$1100.00 Il m Prize5Think of All the Devices You Ever Saw Made from Cigar Boxes.

CIGAR BOX VIOLIN

PIN HOLE CAMERA*SLOT FOR BRASS GUIDES

PLATE HOLDER BRASS PLATE

VELVET ORFELT FLAP

O

PIN HOLEOR LENS

''//etewii.'

rai-» O

CIGAR BOX FILING CABINET*

O*TOYS*

(....'-'N--....7-.-..s,

1 --4- '

RABBETEDFRAME STRIPS

TUNING CIGAR BOX WOOD

*FORK GLUED IN PLACERESONATOR

CIGAR boxes are cheap. As a matter offact in most towns they are thrown

away by storekeepers. Why not make gooduse of these? The wood may be used forvarious purposes, and the cigar box, eithercut or whole, finds numerous uses. On thispage we are showing examples of variousdevices in which cigar box wood is usedentirely in their construction. We wantmore ideas and will pay for these sugges-tions. Of course,. none of the uses for cigarboxes or cigar box wood depicted uponthis page, will be awarded prizes.

It will be seen that you may constructanything using cigar box wood exclusivelyin the building of the device. It can be atoy, a table, a piano or a watch charm.Fig. 8 on this page is a cigar box tele-phone. A hole has been cut in one side ofthe cigar box, and the string passes fromthe other side to a duplicate box at a neigh-bor's house. The string must be tightlyheld. Fig. 9 is a simple stereoscope con-structed as illustrated. Fig. 10 is a methodof using a cigar box so as to permit the en-tire family to enjoy the radio concerts froma receiving set of relatively low power am-plification.

The conditions of this contest are:Contest closes in New York on March

10th at 12:00 o'clock midnight.All material must be in our hands at

this time.Participants are not limited as to the

number of entries.Everybody, man, woman and child, is

eligible.A sketch and a 100 -word article are all

that is necessary, although models shouldpreferably be submitted.

In event of a tie for any of the awards,participants so tying will be given prizesidentical to those tied for.

$100.00 will be awardedTHERE ARE TWELVE PRIZES

AS FOLLOWS:First prize $25.00Second prize 20.00Third prize 15.00Fourth prize 10.00Four prizes, each of 5.00Four prizes, each of 2.50

RECEIVER

a LOUDSPEAKER

AA

*POST CARD PROJECTOR*

BRASSTUBE.

POST CARD

CIGAR BOX DOUBLECONVEXLENS

CIGAR BOX TELEPHONE*

LIGHT

POSTCARDETC.

0MIRROR

EYE 1,

GLASSLENS



- p

\r\d- CA AC fo Everyslacod'BY PROF. JOSEPH DUNNINGER.

NO. 10 OF A SERIES.

877

t

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I ;

DUPLICATE SHEETPASTED BENEATH

TEAR ALONG114. DOTTED LINES

-.

AND PLACEPIECES ONOPPOSITE SIDE 1. .t FOLD

N..

A ,

i

OF FOLDED SHEETTHEN PLACE ON

,

'''',

141,.7.--

c-;--.1-

ni w III'\

4/ TABLEWITH

l'iti/ SIDEFOLDED

UP AND UNFOLD/I P I,i \ TORN

PIECES1 4-/ Dat. FOLD

A sheet of paper is held up and then torn longitudinally in three pieces. These are

placed in front of each other and then folded in hirds. Some one is requested to

initial the paper, and when it is opened, the paper will be found whole again. Two

papers of identical size are pasted together. One of them, however, has been folded upas shown in the illustration. When the paper is torn, the performer is careful not to showthe folded piece. These torn parts are folded up. The whole sheet is opened.

A box of matches is removed from the pocket and he trickster lights his own cigarette.His friend is waiting for a light and asks for it. The book of matches is closed andhanded to the waiting guest, so that he can light hi own cigarette. When he opensthe match book he finds it empty. This stunt is ea ily performed, it being necessary

to tear two match books so that one will be complete, except for the cover, and theother will contain no matches. The group of matches is then placed within the cover,and after a light has been obtained, the matches are slipped out of the cover and thecover is closed.

HOLE THRUSTEM OFGLASS AND

STAND-

PISTON

SPRING

SPRING

STRINGATTENDANTOFF STAGE

PULLEY PULLS STRING

IA glass may be seen resting on a small magician's table. Into this is thrown a bor. jumps up and down in it. Two leaps signify "yes" and one "no.'' A knitting needlerowed coin. The glass will now answer any questions because of the fact that the coin passes through a hole in a glass. An assistant off-stage, operates the mechanism.

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111 lll q((/ /If/ ////'The performer takes a sheet of paper and rolls it up to form a tube. To demonstratethat it is empty, he holds a flashlight at one end, and permits the beams of light to passthrough the tube. He drops the flashlight through it, and removes flags and ribbons from

this empty tube in vast quantities. The flashlight is fitted with but one section of theusual battery. When the flashlight is d opped through the paper tube, the handkerchi fcontainer remains within it.



The Hezvena jznuzlryBy ISABEL M. LEWIS, M. A.

of the U. S. Naval Observatory

0N

oc

I-In6.1

JAN. I; 9 P.M.,, 15;43 '1

" 34-7

SOUTHERN HORIZON

ECLIPTIC

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If this map is held over the head with the "Northern Horizon," north, the position of the stars in the heavens will coincide with their position on the map. It may be used any timeduring the month between 7 and 9 P. M., though at other hours and days than indicated the stars will have slightly different locations.

WINTER evening skies are the mostbrilliant of all the year. Seven starsof the first magnitude and more

than twice as many of the secondmagnitude will now be found in theeastern sky. Ruddy Aldebaran in Taurusand golden Capella in Auriga are close to themeridian The far-famed cluster of thePleiades is due south of Perseus which isdirectly overhead at this time. The Hyades,another noted group in Taurus, lie a little tothe southeast of the Pleiades. They are eas-ily distinguished by their distinctive V-shapeand by Aldebaran, marking one point of theV dnd the eye of the Bull. Just to the southof Auriga will be found the two stars, one

of the second magnitude the other of thethird. They mark the tips of the hornsof Taurus.

Orion is now high in the southeast andno constellation in the heavens can rival themagnificance of this mighty celestial hunter.All of the principal stars in Orion. with theexception of the red giant star, Betelgeuse,of which we have heard so much in the pastfew years, are members of an associatedgroup of stars that are involved more orless in a vast nebula that is probably aboutsix hundred light years from the solar system.This great nebula is most strongly concen-trated around the star Theta in the Swordof Orion which is a sextuple star, that is,

it is made up of six stars in a connectedsystem. Four of these-considerably bright-er than the other two-form the well-knowntrapezium of stars in the heart of the GreatNebula. It is generally granted that thereis no finer object in the heavens than thisGreat Nebula in Orion which can be seen toadvantage even in a small telescope. It takesa powerful telescope, however, to reveal thebranches and ramifications of the nebula thatenvelope the entire constellation in its folds.

Diagonally opposite to Betelgeuse is Rigel,a true diamond of the stars, and probablyone of the super -giants of creation. It is anexcessively hot and massive star of the us -



Science and Invention for Janata -L.1924 879

ersureArchg (he Eitalea'Sensitive Thermocouple Creates Infinitesimal Current From Their Light.

BY EDISON PETTIT,Astronomer, Mt. Wilson Observatory

TO GALVANOMETERMIDDLE WIRES PERMIT OFUSE OF ONE OR BOTH COUPLES

1FOCLULT WINDOW

-JUNCTION OP.2ria-Rmocotr.PLE,

ASTRONOMER OBSERYESSTAR & COUPLE THROUGHTHIS WINDOW'

Above is the double thermocouple on whichthe star image falls for heat measure-

r ment.

Tie dome of the Mount Wilson Observatory where the present measurements

were taken. The thermocouple was inserted at the focal place of the telescopeand the wires run to galvanometers.

LIGHT FROM'.5rms ENTER,

SKELETON TUBENERE

-.FOCAL

PLATFORMS FOROBSERVER

MIRROR IOCC/ArDIAMETER

_TELEPHONE'TO COMMUNICATEWITH OBSERVERAT CALI/ANOMETE"IN BAsgm2NTTHERMOCOUPLEcitszrEYA' PIECETHERMOCOUPLEATTACHED BEHINDTHIS.

LEVER PLRsarprnva IMMOXOR s.FrcritamGUIDING HANDLE,FOR TREBNOCOUNE

At the left below is shown the Hooker 100 -inch reflecting telescope with which the pres-ent measurements were taken. The reflecting inirrcr is at the bottom of the skeletontube. It is concave and focuses the beam of light to a point. The thermocouple is in

BLACKENED IN AECEIVERS

BISMUTHg

TIN -BISMUTHALLOY

Top: Telescope eyepiece showing the

thermocouple in place. Bottom: Wiringof double couple.

serted at this point on movable supports. The couple is made in two parts and eacpart may be used separately, each deflecting the galvanometer in the opposite direction.Thus checking the results.

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; ,`BETEL GE MX ELM"

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THE SIZE OF THIS DOT1,....:i.. ,..

11111111 11111111.111111,11111.111111111111111111 III i11111i11111.111111

COMPARISONS

THE observer can see the thermocouple at alltimes. He focuses the point of light first

on one junction of the coupe and then on theother, the deflection in each case being in theopposite direction. Thus he checks each meas-urement. Above is shown the eye -piece of thetelescope. The couple is placed directly be-hind it. The telescope is also equipped with aspectroscope, used with the couple. so the heatemitted by each color of the star's light may

be measured.

AT the left are shown comparisons of the heat11 from the stars that falls on the earth. Ifthe whole orbit of the earth around the sunwere shrunk to the size of a pin head, AlphaCentauri, the nearest star, would still be 225feet away. Its heat has the same effect as

the heat from a candle at the distance of amile. If the heat from the star Betelgeux,absorbed by the United States were concentrated it would hardly equal the heat of the

st.n on one square foot of its surface.


titiO Science and Invention for January, 1924

. Can IvoIn. rohsvn-r These PTC079 ems?Everyday Scientific Problems Involving General Laws.

THE DRUGGISTS BALANCE

SHORTARM

F

LONGARM

1

A certain druggist is accustomed to weigh his powderson a beam balance one arm of which is slightly longerthan the other. Of this defect he is ignorant sincethe short arm is properly loaded by a set screw tomake the beam balance. Suppose he places his weightsJust as frequently on one pan as on the other will he

gain or lose on account of the defect?

mlllllll'" I

PLATFORM SCALE

annenrcual,n,.

ff,5CAC

A man wishes to weigh a load of coal but finds thatthe platform of the scales is too short to accommo-date the whole wagon. He decides to obtain theweight with the front wheels on the platform andthen with the rear wheels on the platform. The sumof the weights thus obtained, he figures, should be

the total weioht. Is he correct in this assumption?

BY ERNEST K. CHAPIN, M. S.

Il

WHITE _nil

RUBBER

11

SAIL

R QUEST/ON OFELA577CITY

Take two balls, one of rubber and the other of solidglass. Release them from the same height and letthem fall to a cement sidewalk, or better yet to a flatniece of sheet iron or other metal with an absolutelyflat surface. Let them be of the same size. Whichwill bounce higher, the glass ball or the rubber one?

CONSTANTDOWNWARD

SPEED

SCALE

PITCHEROF WATER

A FEW EXPERIMENTSIN AN ELEVATOR 5

Suppose an elevator drops quietly and at constantspeed, could an individual tell if it were in motion?Suppose a man in the elevator stood on a weighiiscale when it started to drop, what would be theresult? Suppose the elevator were dropping at thespeed due to the action of gravity, what would happen

if a pitcher of water were inverted in the cage?

THE PROBLEM OFTHE SWIMMERS

Two swimmers of equal strength and ability race acrossa river. One swims half a mile and returns across theriver and the other swims half a mile down stream andreturns. They start and finish from a raft in midstream. If they are of equal power and of equal skillas swimmers which should win the race. Both are

forced to combat the current of the stream.

WHY PUT BOILED EGGS IN COLD WATER 6

It is said that if hard boiled eggs are immersed in abath of cold water immediately after they come out ofthe boiling kettle they will be much easier to peal.Is there any scientific foundation for this fact? Is it

actually the case?ANSWERS TO THESE QUESTIONS AND THEIREXPLANATIONS WILL BE FOUND ON PAGE 929.



Scneninfic M`conceptnonaBY RAYMOND B. WAILES.

COULD YOU DROWN THESE FISH ?

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DOES THE HEAT OF THE SUN

N SMOKER: S FINGERS REALLYN/COT/NE ? CAUSE SUNBURN?

Strange as it may seem, fish may be drowned by simply tak-ing the dissolved air out of their aquarium. This can bedone by boiling the water and then cooling it. It is be-cause of the necessity of dissolved air in the water that astream of fresh water or a jet of air is forced into artifi-

cial fish ponds where there are numbers of fish.

Very little, if any, of the rich brown stain that appearson smokers' fingers is nicotine. The stain is composedchiefly of tar as formed by the burning of the carbon inthe cigarette. Nicotine is a deep brown oily substancebut there is little of it that is not volatilized with the

extreme heat at the end of the cigarette.

Most people who sit long on the beaches in the hot sunthink that it is the solar heat that causes the tan, orsunburn, as it is called. The effect is caused by the ultra-violet rays in the sunshine and not by the extreme heat.This is proved by the fact that if these rays are filtered

out there is no tan even in the hottest sun.

,r,AREYEASTaBlE7.5WHICHAN

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.

PRODUCEALCOHOL/CBEVERAGEWHILEYOU,alk,winr,PO

lil

SIBLE?

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DYNAMO MOTOR

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COULD YOU SEE THEBONES IN YOUR NANDIF HELD BEFORE ANX-RAY TUBE/NTH/5

INNER?

al

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Ilme isimaatp, \layjragt.

ro iicHrs m.(-- namismair

WHY NOT RUN ,7 DYNAMOWITH A MOTOR AND USE CURRENTPRODUCED BY THE DYNAMO FOROTHER PURPOSES?

With the advent of prohibition there were many firms whoclaimed to manufacture yeast tablets that could be drop-ped in a drink and would produce alcohol content "whileyou wait." This is impossible as it takes some time forthe live yeast organism to perform its work of making

alcohol from the sugar in the drink.

The scheme shown above would work if it were possibleto manufacture a dynamo and a motor that were mechan-ically and electrically perfect. The loss in friction takesbetween ten and twenty per cent of the power of thetwo machines. Aside from this loss, the machines cannot

be made electrically perfect.

X-rays affect a photographic plate but are invisible to thenaked eye. In order to get their penetrating effect, i.e.,to see the bones in the hand with the aid of an X-raytube, it would be necessary to use a fluoroscope screenbetween tl.e eyes and the hand. This screen would show

the effect of the rays.I...

IS A BRASS" P/N POISONOUSIN REMOVING SPLINTERS?

,

'\ \\

YELLOW SOAPS ARE CALLED1205/N SOAPS-

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irr_

if)k 40,

IS' A PO4-N )

9 4 17 v1V )

DOES" IT MEAN THAT ROSIN`

IS USED A5 AN ADULTERANT?

II111111111:11111111

I 1DOE SALT THROWN ON A F/RECAUSE IT 70 BURN WooRousLY?

A brass pin or needle is no more poisonous to the bodythan a steel one. The danger in both cases arises from theuse of an unsterilized pin which may have micro-organismson the point which is used to prick the splinter or to openthe blister. These organisms cause the infection, not the

nature of the metal used.

Many of the heavy yellow soaps have a comparatively highresin content. This element used in the manufacture ofthe soap is not, as is sometimes thought, used as anadulterant. Its addition causes the soap to produce arich, highly detergent lather that is very useful in dis-

soiving greases and oils.

When it is wished to make a fire blaze up freely, saltsometimes thrown into the flames to cause the effect. TheBureau of Mines, in a recent series of tests, has conclu-sively proven that the flare-up following the dosage of saltis simply a result of the sodium flame and not because of

a better burning fire.

- li II/\\ /_-__.-

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WHAT MAKESA COLD GLASSCRACK /F HOT *WATER /5POURED liINTO /T? ;,;

'

(

WHAT CAUSES THE SOUND WHEN A-.:,. 5E17-SHL /5 HELD

e TELO THEEAR?

1 '''''''i°

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OF THE SEA?

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---'-",--- .,-ao -------7 - - -- --- 4u,vir :;% ....,In.-%:- _.-,-Ar---in-:- '----

12itasmr...?Wh'Y DOES AN OIL LAMP GIVE BET-TER LIGHT WITH THE CHIMNEY ON?

M 1

The lamp burns much brighter with the chimney because A glass breaks when hot water is poured into it because A sea shell sounds when held to the ear simply because Its

the chimney causes a draft which allows the carbon to be of the difference of expansion between the outside and the form magnifies the sounds of the room and pulses in the

more high), heated giving a brighter flame. inside due to the higher heat on the inside. head. The least vibration causes an "echo."



VaMMOSIVerl. VMS XiMSSintaSt.v." INVOMMINIellasisi5tiZIOIXV.Ks:OSelSiSVOSWFOs7iCsCOMtiSAVisViss.ssCa\wi

Ghost Spectacile for Amateur 5tage

11

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CUTOUTPORTION

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TACKED TOWOOD STRIPS

PABINWTHESD ONBLACK ---1--AUZE

SCENE

DEAD BLACK CLOTHBEHIND OPENING

FIGURE

OVER OPENING 4111.1 LIGHTRHEOSTAT

tzt.

GAUZE

Many times amateur productions on the stage are put to it to show a ghost or appari-tion. A simple method of creating the illusion is to take a spot in the back drop, saya book case, cut out the regular canvas upon which it is painted and substitute theatricalgauze. Paint the same piece of furniture on the gauze and drop a solid black drop be -

USES

hind it. When the apparition is supposed to appear it is only necessary to place thfigure behind the gauze, darken the stage lights and throw light on the figure. Thusthe figure is seen through the piece of furniture. He disappears when the lightsare turned up, and the light is taken off the figure.-L. B. Robbins.

R SCRAP CONDUITHand protection oreropes and cable

OltPail handles 4Adjustable

4,/

students lamp

Fri

Chesthan es

Tool loops for heavytools

Hot airatake

i loll/ ludllllu

011111111111111111111111'" An anti kink or ant;Protection against pinch forhoselineschaFin4 or vvires,Ohains,

-ropes

fr if:, rt.

Fexible -small machine

well oiled.

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Id

Coupling formust be kept

All amateur electricians are confronted with the problem of disposing of scrap bits of conduit. Amateurs do not like tothrow away anything-that's why they are amateurs. Above is shown some of the many ways scraps of flexible conduit, tooshort to use in regular wiring, may be put to use. Any number of handles may be made by placing short strips of theflexible metal over stiff wire or cord. If there is a piece of larger diameter available it will be found very handy in con-structing a hot air lead for the carburetor of the car. If a couple of the end fittings are handy, a very presentable studylamp can be made, as shown.-C. R. Mullin.

CLEANER KIINK

,11 f 11 sir

.2h0'llexi a #iiiegitensan

1Pipe runthroucjhwall pot.

titoon

fl

witchOutlet

Vacuum o eerie

11 pipe,brass orwroughtiron

Outlets

Connection for sweenerrnotta

By passing a pipe line up through the partitions of a houseand fitting it with plugs on each floor and attaching it tothe vacuum cleaner in the basement and using a hose with

a nozzle time can be saved.-G. A. Luers.



St Effects for MiniaturMiniature Theatre in Which Wonderful Effects Can Be

All of the parts of the electrically operated toy stageshown above are found in the box. This is hinged atone end and grooved on top, so that the various scenescan be slid in and out. The proscenium consists of four

separate pieces.

One of the scenes as it appears from the front of thestage with the footlight turned on fully. These scenescan be made from paper cutouts, Sunday supplementsor other art pictures. The dimming light is then turnedlow by means of the rheostat, which causes the frontstaoe illumination to be produced entirely by the bluelight. A beautiful firework scene is now in evidence, andthe surprising feature is that it moves and is colored.

Even the picture shown above can be employed in thisminiature theatre, in which the curtain rolls up anddown for each change of scenery. The night effect ofthe picture is shown at the right and is easily attained.

Those portions of the scene which are to be illuminatedfrom behind, are generally made of thin paper. Aboveis a night ocean effect. As the roller curtain us movedfrom one end to the other, the waves move and the rain

pours down.

BY DR. ERNEST BADE.

Rheostat

insFOrtner

Another back view in which the tissue paper part of thescene is clearly shown. This is a rising sun effect overa lake. The method of producing wave ripples simu-lating reflection upon water is effected by rocking the

wave device back and forth.

The treWorked.

Back stage two T-shaped pieces of wood containing fourdeep Grooves are erected. At the rear a V-shaped pieceof wood, having several miniature incandescent lightsmounted upon it, may be seen. The back drop is the

most important part of the scene.

Two cardboard wheels are cut out as illustrated above,and covered by tissue paper which has been colored withcrayon pencils, are rotated by means of the small driv-ing wheel also made of cardboard. A cord belt con-nects the three wheels as shown. When illuminatedfrom behind, the effect is startling. The circuit diagram

is shown at the left.

The manner in which the effect is produced is hereillustrated. The rising moon is merely a hole cut in aroller curtain. The waves are cut into black cardboard

which rocks back and forth.

In the back scene effect illustrated above, lightningflashes through a dense forest. The lightning flash cutinto the picture, is clearly illustrated. The shutter

merely cuts off the rays of light.



5Treoacopiic nrrawling Method.

-FOCUS THE EYES ON A DISTANT OBJECT-

elif

ipnolIntnr

ef

- ,11.1

rill IT.t

Iftr

The making of relief drawings is a comparatively simple matter. As shown above, it is only which is to appear in the right side a little to the right. If the above drawings are heldnecessary to make duplicates of the drawings, offsetting that part of the image that is to in the plane of the eyes at the regular reading distance and the eyes are then focused aton the left side of the completed drawing a little to the left and that part of it some distant point they will stand out in stereoscopic relief.-Ernest K. Chapin.

ome-Made Laboratory EquipmentCa/ ondotted Mies

Iron Coss tubes fromCrucible medicine dropper

5//d/iy rnein6er-

f/ask kanhp/ hal,

Ring sands ben, Tongs and friang/eAVM wire beef from wire

Sand baM forheating f/a5A-

110/ch crystalevaporator.

Water bath

lie/A/ fuone/Pram or/ (-aft '

Alcohol. /amp fromoil can

01/ paper filter -paperholder or funnel

Many experimenters living away from the larger cities encounter much trouble in getting cap. Short lengths of glass tubing may be made from ink droppers. A serviceable flask isthe kind of apparatus necessary for their experiments at a reasonable cost. Above are made from a large light globe. An alcohol lamp and funnel is made from an oil can.shown some of the ways the experimenter may manufacture his own apparatus from mate. Ring stands, triangles and tongs are made from stiff wire. Filter paper holder is maderials found at home. An iron crucible is made from a short length of pipe and a pipe from waxed nauer.-Charles D. Tenney.



Cork

Novel Wet Cell

Magnesium'a'1/fit;

\ ICarbon

_ -

Brass strips toholdCarbon

2025Solution ofAmmon iLrnt '

Chlorhydrate

Wood screwMaigrtesiwin

Rod.1:8Volts per

t

A does not touch the Solution_when rack is straight

When/- touches the Solution -Current flowsA simply constructed battery that will deliver 1.8 volts per cell. It is constructed ofcarbon and magnesium rods in Ammonium Chloride. The thumb -screw takes the mag-nesium out of the solution when the cell is not in use.-Chas. Mohr. At the right areshown several uses for discarded valve stems. A-As a bolt. B-As an adjustmentscrew for book -type variable condenser. C-As an intake valve for a compressed air tank.D-As an air valve in the top of the fuel tank. A few strokes of the pump helps the

car over the hill. E-Compression tester. F-Sugar tree spile.-J. T. Garver.

Pipe Sige Chan es

Uaes TOT Valve Core

-A

Auto holybat

0-,*(1

I ---

I -C-1'

Compressor

I

reriner condenser

Vaccu,unt. Cleaner Use

Cei/AV brockel

A Hi&Wall br2ctet_-

Hanci/e---

Rheo57101'

0o

o

Deta/7 ofrval/ brarke/

At the left is shown a simple method of finding a large pipe that will carry the sameamount as two smaller pipes and vice versa.-Geo. G. McVicker. Above is shown amethod of using the vacuum cleaner to force fresh air into rooms where ventilation is

impracticable by ordinary methods, such as dark rooms.-L. B. Robbins.



,V./...4,241" J...034410ger444021/24V .4.241/7/1411141/' .444^.42^,

Fruit trainer

A very cheap strainer for fruit juices is made by stitchinga sugar sack to a barrel hoop and supporting it on threeslats over a butter tub, as shown in the sketch above.Wires hold the slats in place. -Mrs. Florence Swallow.

Temperin Thols

To keep the heat from running too far up a small tool whentempering it, insert it in a raw potato. -W. A. Kyle.

Pin HoJ ViSfiCkri

...,:rue:/01./' .444,

Edited by S. GERNSBACKFOR PRIZES PAID SEE PAGE 856.

CoffiTee Grinder

When in camp or away from home, a convenient coffeegrinder is made with a beer bottle and a large can, asshown in the above sketch. -I. D. Burkett.

"siiveTed Egg

If an egg is thoroughly blackened in a flame and droppedin water it takes an iridescence like silver.-Ethel Amine.

Dancin ° Wire

If two glasses are filled with water so that they emit thesame musical note and a short bit of wire is placed atopone of the glasses and the other is caused to sound themusical note by rubbing its top with resined fingers thewire on the other glass will be found to dance. This isdue to the fact that both glasses vibrate in unison tothe musical note sounded. If a violin is handy and the

With a pencil point punch a small hole in a bit of paper. same note is struck on the violin and wires are placed onSmall print may be read through it easily.-J. N. Morrison. top of both glasses they will both vibrate. -P. Rolatom.

CorM. Screw

Wood -screw-

Cork

When the cork screw is lost or misplaced try using a largesized wood screw in its place. If the screw is passedthrough a wooden handle it works better. -B. Willard.

llneTtia ETsperiment

If a dime is placed on top of a stiff hoop of paper whichrests on a bottle top as shown, and the hoop removed by aquick sidewise blow the dime falls in the bottle...a. Zyl.

Win.n-o' -the-WispWire - - - - .,-Flame

Carbonicada gasin jar

Nate -Sa,Ouricacid

Candle

Sotto crs7ialsIf a lighted candle is placed in a bottle containing solutionas shown above, a flame will burn on top of the bottle aslong as the candle remains hot. -C. A. Oldroyd.



IFIO' V -TOe4f41.4444,e4444141Wer. .V.6444414,S.4,e/Pe/gre.,...0,?40^

This department will award the following monthly prizes: First prize, $15.00; second prize, $10.00; third prize, $5.00.The purpose of this department is to stimulate experimenters toward accomplishing new things with old apparatus or old material, and for the

most useful, practical and original idea submitted to the Editors of this department a monthly series of prizes will be awarded. For the best ideasubmitted a prize of $15.00 is awarded; for the second best idea a $10.00 prize, and for the third best a prize of $5.00. The article need not be veryelaborate, and rough sketches are sufficient. We will make the mechanical drawings. Use only one side of sheet. Make sketches oil separate sheets.

Auto Tool NitFIRST PRIZE $15

A few strokes of the hammer and saw will save the troubleof digging the hammer and the rim wrench out from underthe back seat and untangling them from the skid chains ifthe above shown idea is put into practice. A short lengthof board is sawed to fit the space under the front seatcushion. It is then equipped with metal clips to hold thetools. -John Blank[11 author will send address, pri;c will be forward-

ed.-ED1TOR.

fr) ench AnvilSECOND PRIZE $10

1111' 1F 111111111 1 11

By sawing the handles off an old flat -iron and cutting a

receptacle to fit the body of the iron on the work bencha very useful bench anvil is made. -Chas. T. Allen.

Col ''iptrizag Used Tot,- Emirate' 5: 11)M to,

Long ' enible Springa, a used lot -Screen Doors Paper ra.ste'rter

Ertlarged. Duplicate

A long, flexible spring, such as the type used to hold screen doors in check, may beused to make enlargements of drawings by the process shown in the sketch above. A

stout nail is lined in one corner of the drawing board and a pencil stub or paper fas-tener is placed in the center of the spring as an indicator. The drawing pencil isthen attached to the other end and used as shown. -G. A. Luers.

p©n Te6lcherTHIRD PRIZE $5

For those children who seem prone to use the left handin spite of the daily admonitions of mother and father thelittle device shown in the above sketch will do more toteach them the correct usage than all the scoldings theparents can hope to give. It is only necessary for thefather to bend one of the old teaspoons in the shapeshown above. The shape makes it impossible of use

except with the right hand. The small part of the spoonhandle is heated over a gas jet and the bowl of the spoonbent at right angles and to the left. -Otto A. Koehler.

UniVe7a.a.11 IIMd1nca.tor for Poison1W)

The young lady to theright is putting thesandpaper on thebottles. Note thatmost of the body ofthe bottle is covered,so that the warning

is certain.

ottIlesAny number of schemes formarking poison bottles havebeen suggested to this de-partment in times past. Thisscheme seems, however, to beone of the best submittedsince it is easily installed andwill lead to no discomfort tothe person grasping the bottleas is the case with some ofthe ideas submitted. It isalso obvious that it is prac-tically impossible to touch thebottle without receiving thewarning as to its contents.

By the simple means of pasting a strip of sand paper over the face of bottles contain-ing poisons the danger of getting the bottle by mistake on account of darkness is elim-inated. The flint paper is pasted clear around the bottle. -Nelson Edwards.



' eraster''7,7:c 7, .e

../44,"?..." 4.4.4./44^../`

Path of Tram-Atilanac Radio MeazageHow Messages Are Handled by World's Largest Radio Stations.

ROCKY PT.C)

<_9 RIVERHEADL.I.

18

AURAL AND VISUALRECEPTION

6V-E/Ach, 'NEW YORK

NEW YORK

- - -11110. - -ATLANTIC OCEAN

MONITORREC.AERIAL 1Thinarla

THE path of a trans -oceanic radio message may be readily fol-lowed by referring to the numbers on the diagram given

herewith. Either by telephone, 1, or by messenger, 2, thetelegram is delivered to the desk, 3. It then goes to anoperator who types it diagrammatically on a tape which goesto an automatic transmitter, 5. Pulsations are sentthrough a 70 mile wire circuit to the alternators shown at 6.The station at Rocky Point, L. I., controlled from NewYork City, is taken as an example. The alternator thensends out the message from antenna 7, and it is received at8, in Europe. As a check on the outgoing messages an aerialin New York City receives them from Rocky Point. They'go through the radio frequency amplifier, 9, the tuner, 10, thedetector, 11, and the audio frequency amplifier, 12. Thesignals are then reproduced on a loud speaker and also on atape recorder for check purposes.Incoming messages from Europe are received on the antenna16 at River Head, L. I.; they are tuned, amplified at radiofrequency, detected and amplified at audio frequency at 17.They are then transmitted over a land line to another audiofrequency amplifier in New York City indicated at 18. Fromthis the signals are recorded on a tape at 19 and also repro-duced audibly in the phones as at 20. The operator typesoff the message, which then goes to the desk, 21, fromwhence it is routed to the addressee either by telephone, 22,or by messenger, 23. At times the messages are sent bymail, when the addressee cannot be reached otherwise.The photograph in the center shows a typical receivingoperator's desk. The operator in this instance is receiving byreading the message directly off the tape. The men whodo the receiving find this to be the fastest method of work-ing, being even more rapid than audible reception.

I vi`

, - 011

INVENTIONCI EKE Fe "j\-

II 1141

(C)I923 BYI



adko Nnvasi n ContinuesIts Entertainment Goes Everywhere.

New Equipment for Life Boats.

RADIO has become so much a part of the life of the United Statesthat a few weeks ago there was held at Grand Central Palace, New

York, the American Radio Exposition, showing every kind of equipmentand the latest advances made in the craft. It promises to be a yearlyaffair. Above is shown one of the most interesting pieces of apparatusexhibited at the show. It is the new English invasion of the Americanloud -speaker market, the Amphion. Going back to the old principle ofthe long air column and equipping it with a very hardy diaphragm thehorn produces voice and music with surprisingly little distortion and the

device is capable of taking a very strong current.

The young lady shown below is taking the boredom out of gray squirrelhunting by carrying her radio set on her Nimrodian adventures. The graysquirrel is most easily seen just at dawn and dusk and the wait for himto put in his appearance sometimes becomes tedious. With the simpleaid of a small dry battery set and a loop antenna the Maryland girlin the photograph is whiling away the last half hour before her quarrycomes to play. She was one of a large hunting party that took the set

with them into the woods so as to while away spare moments.

THE Worid's Series was a serious time for thisyoungster (above) for he lived a long way

from the village score board and the wood pile

needed attention. But he took the disaster outof his position by moving the radio set from up-stairs so that the two great events-the Series and

the wood pile both were attended to.

By installing small one -quarter kilowatt radiosets (left)-and a small gasoline motor with al-

ternator lo furnish power-aboard life boats, anEnglish chandlery firm hopes to reduce the loss

of life caused by the loss of open life boats in

heavy storms. The aerial is directional.

In the Amateur Built radio set contest at therecent Radio Show in New York, one of the mostpopular entries was the set of Miss G. Alexan-der, whose set (below) was built as a replica ofEiffel Tower. All the apparatus is concealed with-in the tower with the exception of the honeycomb

coils.


Science and Invention for Janvary, 1924

J[dist in to NewsNovel Designs; New French Power Tube.

A NOTHER exhibit that created a great deal of attention at the Radio Show was a set in aplate plass cabinet. It is shown above. The loud speaker accomcanyino it is also of note-worthy design. Below is a step forward in the manufacture of power tubes brought out by aParis scientist and put into use in the famous Eiffel Tower station. It is built up of anumber of parts and can be instantly taken apart for repair. With the constant increase

in the price of the larger power tubes it has become necessary to repair old tubes.

Above is a view of the demountable tube with the fixed elementson the cap and the glass case. The metal cylinder is air -tightand acts as the water-cooling shield. It is also the plate element.

The tube is always connected to a mercury vac-uum pump. (Above) It runs continually whilethe tube is in operation. After a repair is made

the tube can be exhausted in fifteen minutes.

One of the most noteworthy features in examining the apparatu, shownat the Radio Show was the tendency of the manufacturers to wo,k theirsets into some form in which they could be put into the well furnishedhome, without impairing the aspect of the rooms in which they areplaced. The careful householder demands that the furnishings of hishome be ornamental as well as useful. Above is one of the radical de-partures in cabinet design. The set, designed primarily for the useof the broadcast listener is housed in a lamp -like case. It consistsof three stages of radio and two of audio amplification. The loopaerial appears at the side of the cabinet. Batteries a' e in case below,

Distance fiends (or DX hounds, as they are called in the parlance), p'ease note. Above is the newand enlarged transmitter of the amateur station 2CTQ, known to many amateurs throughout thecountry. Mr. Leo Johnson, owner of the station, is shown sitting at the microphone of his new outfit.The improvement in the transmitter is the installation of a new 20 -watt C.W. outfit using four five-watt tubes. Many amateurs outside of the first, second and third districts (the East Coast) will nowbe able to hear 2CTQ, although he already has an enviable record for long distance work and hastaken part actively in the work of the Amateur Radio Relay League. Note the accessible arrange-

ment of the instruments.



Radio Makes TTransoceanic Cfircle

ROCKY PT.L.I.

ORIGINAL DOTSTARTED AT THIS

I.- -4

NEW YORK

RIVERHEADL.I.

- - - - - - -

ATLANTIC OCEAN

-PAPER TAPE

v RECORD OF DOTS

aS

(B)/913 By SCIENCE 4-breeler/o,y

Recent experiments started a radio dot from the United States sent it to Europe and re- It was recorded on S. Then it went through 9 and 10, came back to the United States to

turn many times, covering an actual distance of 4,500,000 miles, without the assistance 11, through 12 to 13 and then actuated relay 1, starting itself all over again. At the

of an operator. The signal originated in New York City on relay 1. It traveled to 2 foot of the diagram is the tape record of dots showing how they varied in duration be -

and 3 and then across the ocean to 4, through instruments 5 and 6 and actuated relay 7. cause of the mechanical lag of the relays, becoming shorter until they died out.

Lat st De ft (01 ns hi Raffle Cabinets

Above is a combined side table and radio set.As will be noted the right end drops downexposing a complete receiving set. The loud

talker is also included in this cabinet.

The radio set illustrated at the left could well grace any living room. Bylifting up the front shelf, the set sinks down out of sight and the cabinetfolds up and makes a very nice decorative table. Right: A hand carvedantique model cabinet which houses an up-to-date radio set with power am-

plifier and loud speaker. It is entirely self-contained.

krLOUD TALKER

FOLDING SHELF

COVERS SET

WHEN CLOSED

DRAWER

FOR SPARE PARTS

AND TOOLS

SPACE

FOR

-----NBATTER/ES

In the above illustration is shown a suggestion for amateur constructors whodesire to put their radio set into the best possible form. The loud -talker is

located directly above the set, which latter is covered by cloth. A drawer is pro-vided for tools and spare parts and at the bottom is a space for the storage "A"

battery and 'the "B" batteries.

Above: A sturdy, serviceable model of a radioreceiving set cabinet. A novel system of dialcontrol is used in which the figures may beseen through slots in the face of the cabinet.



a 10 omission o hot° raphsA Recently Developed and Simplified, Yet Accurate Method of Transmission.

Below and to the right will be

seen the transmitting apparatusused for sending photographs byradio. As will be noted, the ap-paratus takes up little more spacethan the average receiving set.A cylinder is rotated by means ofan electric phonograph motor, a

governor being used to maintain aconstant predetermined speed.The photograph, made into a halftone on copper or zinc with a

one -line screen is placed on thecylinder with a stylus in contactwith it. The stylus moves in a

spiral course at a rate of 175turns to the inch. The stylus,working over the indented surfaceof the half -tone causes fluctuations

in the current.

COPPER SCREENCUT OF PICTUREPREPARED FOR

TRANSMISSION

COPPER SCREENON ROLLER

Above: The original photograph and reproductionafter being transmitted by radio. The top photo-graph is the original and the bottom one the re-production. At the receiving end, no trace of thescreen used in making the half -tone is visible,

the only effect being a few vertical lines.

BY A. P. PECK

TRANSMISSION

STYLUS

Above: The inventor of the system of radioand wire transmission of photographs, MarvinFerree.Below at left: A diagram of the transmittingcylinder and stylus contact. The half -toneis prepared on either a copper or zinc plateand then formed on the cylinder so as to fitthe perfectly. The turns atthe same speed as the receiving cylinder pic-turned below at right. The receiving stylusacts on a chemically prepared paper which

turns black or gray, forming the picture.

RECEIVER

STYLUSCYLINDERSREVOLVED

SYNCHRONOUSLY

STYLUS

r-

CHEMICALLY PREPAREDPAPER AROUND

CYLINDER RECEIVING- -

PHOTO BY RADIO

RADIORECEIVER

Above will be seen two unretouched photographsof America's most beautiful girl, Miss CatherineCampbell. The original is at the left. The re-production at the right was telegraphed over a 400mile line. The entire time of transmission is in

all cases less than live minutes.

Above: The receiving apparatusused by Mr. Ferree in the repro-duction of photographs transmit-ted by radio. At the right inthe above photograph is a stand-ard radio receiving set and at theleft will be seen the apparatus forreproducing the transmitted photo-graph. Mr. Ferrie has perfectedhis apparatus to a very great ex-tent and claims that it will beextremely useful in newspaperwork for transmitting photographsof current events. With this ap-paratus, it is possible to carry oncommunication over the same lineson which the photograph is beingtransmitted, both transmissions

taking place simultaneously.

REPRODUCING PHOTOON CHEMICALLY PREPARED

PAPER ONCYLINDER

The scene of an automobile accident transmitted- 900 miles by radio. The original is the lower.. photograph and the transmitted copy is at the

- 1:11 top. With later developments along this line bet-i 0% ter transmission will undoubtedly be accomplished

I and practically perfect photographs Will be repro-duced.



too e BAo)DPTapk-vv- of a VacuumIt c' it v rri the \Looitaco_re of a Dry Cell Vacuum Tube.

1

Above: A blown glass globe as itis received by the manufacturersof the vacuum tube, from theglass blowers. This bulb goesfirst to the machine shown at theeight where it is cut to size and

1,1 a mailer tube.

Above: The machine which pertorms two operations on theglass bulb. At C, a hot flame is directed on the topand a hole blown therein. At A, a glass tube fromhopper B is sealed to the ripening thus formed. This

tube is to be used on a later step for evacuation.

The above illustration shows a smallfoot -fed arc, the electrodes indi-cated by A. This arc is used toweld the filaments into vacuumtubes. The elements are indicatedby B. It is impossible to use

snider in this place.

10 The bases are now sealed on the tubas and theconnections made to the prongs. The younglady in the above illustration is testing theconnections. At this stage many tubes are

0,440 rejected because of defects in the filament.

-.MW111W

The glass tube as shown at 3 andthe elements as at 5 are now sentto the machine illustrated aboveand welded together. A is the long

thin tube and B the glas,_ bulb.

ost"'""`"etoozuhe

Left: The form on which theelements-the grid, plate andfilament- are placed. Notethat five wires extend above o

the glass tip while onlyfour go below. The odd

wire supports the grid.

Left: The embryonicvacuum Inbcwhen it leaves the machine illustratedet 2. The narrow glass tube is nowNi integral part of the bulb, and theunit is ready to receive the el.ments.

Above: The ap-pearance of thebulb and glasstube with theelemc:te sealed in.

51

Above at right: The elements of thetube firmly mounted on the live penjetting wires. The lower wires aresoldered to the prongs on the haze

of the tube

IAbove is shown the testing table where bulbs are tested for plateand filament consumption. After being burned for are hour- on this table, the bulbs are set aside to age and are testedagain, whereupon, if they come up to the stridard, they are

packed for shipment.

A indicate, the vacuum tube. B

shows the connection between thetube and the exhaust pump. C

shows a coil for exhaustion by

heating and D an electric furnacefor baking to assist in exhaustion.

12 Above: T h e finishedvacuum tube as it ap-pears when ready for theconsumer, carefully tested

and ready for service.

4111111111111111MMIIIIMI


89 -1 - Science and Invention for January, 1924

BROADCAST__ STATIONSlip

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iTHE two photos directly above show the interior ofthe operating room and the studio of station WSY,

Birmingham, Ala. The studio follows the regular linesof construction with the exception that the main mi-crophone leading to the modulators is suspended withelastic from the ceiling of the studio. There is a spe-cial small microphone that is used to pick up thepiano and the Victrola when they are used in connec-tion with programs. The operating room seen in thelower of the two photos shows the neatness and theskill that has been used in assembling the station.All controls for the set as well as the motor -genera-tors are gathered together in order to make for idealoperating conditions.The top photo at the right shows the operating end ofstation WOS, the State Marketing Bureau of Missouri,located at the capitol of the state, Jefferson City.

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MOMSitting in the photo is J. M. Wittem, announcer andprogram director. Standing, is R. J. Engler, the en-gineer in charge of the operation of the station. Al-though the broadcasting of the station has principallyto do with the announcing of prices on farm productsand general market conditions, programs are broadcastunder much the same schedule as obtains in otherMiddle -Western stations.At the bottom of the page may be seen the PeoriaStar Company's station (WJAN) located at Peoria,Ill. The photo shows the interior of the operatingstation and the talking machine with microphone at-tached which is used in some of the programs. Notethe neat arrangement of the apparatus.

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n Ustun d im ryA Two Control Set With Extreme Selectivity

BY W. L. PEARCE.

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The above photograph shows a front view of the assembled set which is fully described The above photograph is a rear view of the untuned primary receiving set, taken at

and illustrated below. There is one tuning control, the second dial from the left. a slight top angle. Notice the relative positions of the two audio frequency trans -The first dial on the left controls regeneration. Only two rheostats are used, one formers and how the cores are turned at right angles to each other so as to avoid

for the detector and the other for controlling both amplifier tubes. inter -action. The three tubes are placed just behind the two transformers..

Ifir3 To I RATIO. AUDIO 3 TO I RATIO AUDIOFREQ TRANSE FREQ TRANSF. VACUUM

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The above circuit diagram shows all the connections for this very selective yet three degrees on either side of a certain point on the condenser scale will tune out asimply tuned radio receiving set. The primary is "aperiodic," or so designed that station. This allows quite good selectivity. Note that a single rheostat and 41/2 voltit will respond to practically all wave -lengths over a certain band. The secondary "C" battery are used on the amplifier tubes. With U. V. -199s, or C -299s, the "C"is then sharply tuned to the incoming signal. It has been found in tuning this set that battery is very necessary in order to cut down tube noises.

At the right is given the panel lay -out for the set,Photographs of which are shown above. The ex-treme simplicity of the panel should appeal to

everyone; only Mx holes aside from those forthe binding posts being necessary. The posts forconnections can be mounted either on the endsof the panel as illustrated in the above photo-graphs or on the cabinet as desired. If the lot-ter method is used, it will be found that it willdo away with unsightly wires on the front of theset. The two jacks take care of the phone

connections and are so placed that either thefirst or second stage of audio frequency amplifi-cation may be used as desired. Rheostats witha resistance of 0 ohms should be used in thiscircuit if vacuum tubes drawing only .06 am-

pere are used.

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Sometimes when a set of the type described herewith is hooked up, and the set placed positions. It is sometimes found that by placing an amplifier tube in the detector

its operation, a loud noise like the sounding of a deep toned bell will be heard socket and the detector tube in place of the amplifier, this difficulty will be remedied.when the set is tapped or even touched. This is due to the vibration of the elements Mount sockets on felt. The above applies to the dry cell tubes, which have very small

of the tubes and can usually be eliminated by trying different tubes in different' elements, and which are recommended for use in this set.

'TICKLER_-_ ,/4WAXED PAPER

LAYERSD OF

,....-- i/-----PRIMARY/ ---- - - - .

10 TURNS OFi / N2.18 S.C.C.

------.

At the left are shown all the constructional details of the variocoupler used in connectionwith this very selective receiving set. It is of the 180 degree type and any well madeinstrument will answer. The primary winding must be removed and 40 turns of No. 22

wound on the stator. This acts as the secondary of the tuner. In mostScasees. the rotor,rotor, which is to be used as the tickler coil, need not be changed. Directlyover the secondary winding, place four layers of waxed paper or oiled linen. Over thiswind 10 turns of No. 18 S. C. C. wire, fastening the ends of the winding with sealing wax.It is quite essential that large wire be used on this latter winding so that the distributedcapacity will be kept down as much as possible and so that the tuning of the set will besharper. In connecting the set, the movable plates of the variable condenser are con-nected to the filament side of the secondary. This method of connecting eliminatescapacity effects when tuning. It is sometimes advantageous to ground the metal frameof the variocoupler for the same reason. When the rotor is horizontal, the plate leadshould be taken from the bottom of the coil wound on the rotor, and the grid lead shouldbe taken from the top end of the secondary. If care is taken to keep this connectioncorrect, it will not be found necessary to reverse the leads to the tickler coil as usually

must be done when first hooking up a circuit using feedback regeneration.

.

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CIO TOT the 3eginn rARMSTRONG PERRY

No. 23-INDUCTION.

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Upon the magnetic lines of force depend induction.These lines of force if visible would take the form

of circles surrounding the wire as an axis.

When wire is wound in a oil form, the lines of forceintersect adjacent wires as shown above and induce

currents into each other. This is self-induction.

The difference between the two sparks produced as il-lustrated above is caused by the lines of force from

the turns in the coil acting on the next.

I

VLINESREPRESENTS SECONDARY

AT MINIMUM COUPLING ---0-OF' FORCE

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AIR UNDER PRESSUREFORCE V- AIR UNDER PRESSURE

In practical radio work, inductionforce having the property ofmake a transference of energy

An analogy

is made use of in the variocoupler. The lines ofinducing a current into conductors which they intersect

from the stator or primary to the secondary or rotor.is shown for this at the right.

In thecouplerat the

angles.

above illustra ion the rotor is shown at right angles to the stator ofand the amount of current in the secondary circuit is very small. In theright the piston is removed from the cylinder and suspended above it

The current of air striking the curved surface exerts little pressure.

a vario-analogy

at right

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ONE SLIDETUNING COIL

SwITCHES ,".,T,,,

UNITS AND TENSTAPPED COIL

SECONDARY ..-2/i --_- -TO

GROUND TO GRID & FILAMENT1.

The current in the primary honeycombthe coil. cutting the secondarysends out its own lines of force

coil sets up lines of forces. These emanate fromcoil and inducing a current therein. The tickler coilwhich again effect the secondary and set up what is

known as regeneration.

.

Twobaresections

methods of varying inductance are shown above. A slider moves over awire and makes contact thereto. At the right taps are taken off at

along the coil of wire and connected to switch points. Arms makewith the switch points.

path ofvariouscontact

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Both honeycomb and soider-web coils are very efficient. The distributed capacity ofthe coils is low, an advantage in radio work, and the inductance is high. A greatamount of the latter can be obtained in a small space. At the right is shown a flat

view and an edge view of a spider -web coil.

Large inductance coils used to be necessary to receive long wave stations, which thendid most of the transmission. Today their form has changed considerably. The longcoil illustrated above is the old form and at the left is shown a honeycomb coil

of the same inductance, but only an inch or so thick.



In this Department we publish questionsto this Department cannot be answered

mcheand answers which we feel are of interest to the novice and amateur. Letters addressedfree. A charge of 25c is made for all questions where a personal answer is desired.

TO END 7. COIL

TOGROUND

LRIAL

ONE SLIDETUNING COIL

45-90 V B' BATTERY

POTENTIOMETER

.001 MR VARIABLECONDENSER

5 TO I RATIO, AUDIOFREQUENCY TRANSE

C R -51

TO BATT. CONNECTIONSON REAR OF CABINET

45-90 V. BATT.

PHONES)

No. 208. To increase the receiving radius of a standard signal circuit tuner of practicallyany type, radio frequency amplification may be added by following the circuit diagramgiven above. The remarks relative to the series antenna condenser which are given in thetext should be carefully noted, as inattention to points given there will result in the

R. F. AND A. F. WITH STANDARDRECEIVER

(208) George Siedel,writes to the Radio Oracle:

Q. 1. How can I connect one stage ofradio frequency amplification with my typeCR-5 receiver and place after the same onestage of audio frequency amplification?

A. 1. The diagram given in these col-umns shows all the necessary connections.It is imperative that the variable condenserwhich is connected in series with the an-tenna binding post on your set he short cir-cuited or else removed from the circuit sothat the aerial binding post will be con-nected to the grid end of the stator. If thisis not done, the set will not function. Itis advisable to connect this variable con-denser in parallel with the stator so as togive sharper tuning although in some casesit will be found that such a procedure willraise the waye-length to a point wherebroadcasting stations cannot be received.Thereupon the condenser should be removedfrom the circuit.

STORAGE "B" BATTERY QUERY(209) Joseph Karl, Pittsburgh, Pa.,

asks:Q. 1. In making a storage "B" battery

should the plates be pasted in the same man-ner as those in a large storage battery suchas used in automobiles?

A. 1. Yes.Q. 2. What kind of wood should be used

for separators?A. 2. Practically any kind of wood

could be used, but white pine or spruce isbest. Even better than wood are perfor-ated sheets of thin hard rubber.

set's failure to operate. If desired, a honeycomb coil may be substituted for the oneslide tuner indicated in the diagram. Various coils will have to be substituted to coverthe band of wave -lengths desired. The inductance used in the antenna circuit should besuch that its wave -length will tune in the incoming signals.

MULTI -AUDI -PHONE(210) Jan/es McCarthy, Bayonne, N. J.,

Q. 1. Is the apparatus known as themulti-audi-phone still on the market?

A. 1. To the best of our knowledge thisapparatus is no longer manufactured.

io-M1111111111111111A111111111111141.41111111a1uv Mar NM

V,_aururiwinsiiLinammplMOO PM

IIIFAMI=111

One of the first successful types of microphone amplifiershown above. This is the cross section view so that

the solenoid and the location of the compound may be

readily seen.-No. 210.

Q. 2. What is the principle of the multi-audi-phone and how is it constructed?

A. 2. You will find in these columns across sectional diagram of the microphonicamplifier known as the multi-audi-phone.As will be seen, it consists of a solenoidwithin which is a movable core, which inturn is connected to a diaphragm. On the

opposite side of the diaphragm is a projec-tion, the end of which is cup shaped. Closeto this is another cup shaped projectionwhich can be moved closer to and furtheraway from the former by means of a screw.Between these two surfaces and held inplace by an insulating tube is found a com-pound which we believe is carbon in a gran-ular form. The action of this instrument issimilar to that of the microphone and be-comes obvious upon studying the accompany-ing diagram.

A. F. AMPLIFICATION WITH AREINARTZ TUNER

(211) T. L. Jacoby, Detroit, Mich., wantsto know :

Q. 1. Can I add four stages of audiofrequency amplification to a Reinartz tuner?

A. 1. We would not advise you to usefour stages of audio frequency amplifica-tion on a Reinartz or any other type oftuner. Furthermore, if you desire to useamplification with this circuit, it may beadded in the standard way, no change beingnecessary for this particular type of set.Two, or at the most only three, stages ofA. F. amplification should be used.

RADIOPHONE TRANSMITTERTUBE

(212) Gilbert Joyce, Kansas City, Mo.,asks:

Q. 1. Can a U.V.201 vacuum tube beused as a radiophone transmitter?

A. 1. A U.V.201 vacuum tube with 100to 150 volts on the plates will act as atransmitter over very short distances. Anyone of the 5 -watt tubes will give goodresults.

nelio.t$inio111111111111111111111:1211rillirstittm.,.,.,;,...o....11,...111111iititco$FIlitiilliriniumiiiitilitiiii.l...to,.,k .........."..,,,......,,,,n,""...............".."'''''',.''''''

WANTED!!! RADIO ARTICLESWE want descriptions of new radio ideas which you have desirous of obtaining new hook-ups and descriptions of single

worked out in practice. Take photographs of the im- tube sets, reflex and other types which have proven satisfactory.portant parts and make pencil or pen and ink sketches of the We want articles on the latest single tube receptors which re- Ihook-ups or mechanical details, et cetera. We are particularly quire a minimum current from the filament battery.-Editor.



TO AERIAL

VACUUMTUBE

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In some cases it is possible to use radio frequency amplification without any tuningarrangement between the R. F. amplifier tube and the antenna. Such a circuit diagramis shown above. At times it will be necessary, however, to place a one slide tuning coil

in series with the antenna-No. 213.

UNTUNED ANTENNA CIRCUIT(213) Charles Burg, Riverside, Cal.,

asks:Q. 1. How can I place one stage of radio

frequency amplification in front of my sin-gle circuit tuner without an apparatus fortuning the antenna circuit?

A. 1. The diagram in these columnsshows all the necessary connections for sucha circuit. It is advisable to place the gridleak in the position shown rather than iiithe conventional place in parallel with th(grid condenser. An amplifying tube is usedat the extreme left and a detector tube inthe other socket. The potentiometer may ormay not be used as is found best by ex-periment.

SQUEALING(214) Elmer Kayler, Dayton, Ohio, says

that his set howls and squeals continuouslywhen his hand is brought ear any of thecontrols. He asks :

Q. 1. How can I eliminate this and willa vernier condenser be of any assistance?

A. 1. You can probably eliminate thetrouble you mention by shielding the backof your panel with aluminum and groundingthe shield. The trouble is due to the capa-city of your body and can be eliminated asmentioned above. If this work is done avernier condenser shunted across your an-tenna condenser will be of assistance in ac-curate tuning.

VARIOMETER WITH SINGLE CIR-CUIT TUNER

(215) Robert Fitch, Lakewood, Ohio,asks:

Q. 1. How can a variometer be added to

In districts where there is not much radio congestion and very little interference fromnearby broadcasting stations, louder signals will be obtained by using a two slide tuningcoil as shown in the above diagram instead of more complicated and expensive apparatus.

For broadcasting the wave -lengths a small coil may be used.-No. 216.

my present standard type of single circuittuner?

A. 1. The circuit diagram herewithshows how a variometer may be connectedin series with the plate of a standard singlecircuit tuner. Recent experiments haveshown that such an addition to a standardsingle circuit set makes it more selectiveunder almost all conditions.

f a variometer is placed in series with the plate of aacuum tube in a standard single circuit tuner, much

greater selectivity will result as a combination of thefeed -back and tuned plate system.-No. 215.

FIRST!

TWO SLIDE TUNER WITH DETEC-TOR AND AMPLIFIER

(216) C. Saracool, New Hudson, Mich.,requests :

Q. 1. Can you show me how to connecta two slide tuner with a vacuum tube detec-tor and one stage of audio frequency am-plification?

A. 1. The diagram will be found in thesecolumns.

AMPLIFIER TROUBLE(217) Frank Prell, Osceola, Nebraska,

sends diagram of his detector and two -stageamplifier and says that he has placed histransformers quite a distance apart, but thathe still gets whistling noises during recep-tion. He asks :

Q. 1. Can you tell me what is the troublewith my circuit?

A. I. The whistling noise is probablycaused by the way you placed your trans-formers in an endeavor to cut it down.The long leads necessary between your trans-formers have a capacity effect on the cir-cuit, thereby causing the howling. In con-necting up your set, do not have the gridand plate circuits cross each other. Alsotry reversing the leads on the transformers,grounding the filament, and shielding all theapparatus.

Your circuit diagram is 0: K., but wouldsuggest that you connect the fixed phonecondenser directly across the primary of thefirst amplifying transformer.

Variable grid leaks and condensers are al-ways preferable in any type of set, and wewould advise you to try various resistancesand capacities until the correct value isobtained.

RADIO NEWS is the FIRST radio magazine in the world today. It is FIRST in circulation, printing over 250,000 copies a month. It is FIRST inadvertising patronage, carrying a larger amount of advertising than any other Radio magazine in the world. It is FIRST in size, printing more mat-ter than any other radio magazine. And last but not least, it is FIRST in quality. The greatest radio writers invariably write for RADIO NEWSfirst.And befor-, we forget it, RADIO NEWS prints radio news FIRST. Important news can always be found in RADIO NEWS ahead of all otherpublications.

SOME OF THE INTERESTING ARTICLES APPEARING IN JANUARY,Pioneer Pathfinders of Radio,

By Jesse Marsten.The Radio Police Car,

By Armstrong Perry.Some Suggestions for Radio Beginners,

By Bernard Steinmetz.

Break -In Radio Relay Communication,By Lieut. Col. J. D. Mauborgne.

A Balanced C.W. Circuit for Quick Wave -Length Changes,

By John L. Reinartz.A Well Designed Short -Wave Receiver,

By James Wood, Jr.

1924, ISSUE OF RADIO NEWS:Some Suggestions in the Design and Construc-

tion of Aerials,By L. W. Hatry.

C.W. and Radiophone Transmitters-Part IVBy L. R. Felden.

A Practical Neutrodyne Receiver,By Allan L. Hanscom.

111111101i


899Science and Invention for January, 1924

..,awasaatz4440-avvvoopecGr.,2^...a.^..41,01.44.011/24^-,

..e./1/741:1?"'

Auto-AirplayAe

(Pat. No. 1,445,953, issued to Rudolph B. Illpen.) Byequipping an automobile with wings and an air rudder asshown above, the bulk of the car's weight is removed from

the wheels and very sharp turns are possible.

Reverse la.vidder

l- - i ,...----,- . -- ---- ' )....

-----'2-----' .--- - - - - 7 ---'::

*CUP SHAPED RUDDERSWHICH ARE CLOSEDFOR REVERSE

PROPELLER

(Pat. No. 1,449,803, issued to Johnston Robertson Alexander.) When the cup shaped rudders are closed behindthe propeller the force of the water reacts against themand the boat goes backward. The rudders are also used

for steering.

Shoe Salesman's Ventilated St ol

PROTECTINGSCREEN

HEATINGCOILS

Pat. No. 1,460,915, issued to Smith L. Luton.) To do away with the unpleasantness connected with the shoe

alesman's profession, this invention places a fan under the foot rest of the salesman's stool. A current of air is

forced over hot coils and against the perspiring foot. The hot coils and the fan are both electrically operated.

Perspective Movies

MIRROREDSHUTTER

OPENING INSHUTTER

LENS LIGHT

(Pat. No. 1,461,133, issued to Thomas Henry Marten.) (Pat. No. 1,447,893, issued to Irene Leroy.) This tankTwo proiectors. operated alternately, both using the same constructed with collapsible ends, forms a bridge over

film, are claimed to produce movies in perspective. large gulches for whippet tanks, as shown.

f,if!Tf- r .

WM11111111 Ltflint

U.S.PATENT OFFICE

Water Shoes

(Pat. No. 1,463,330, issued to Henry Meyer.) Smalpontoons made of a collapsible substance treated so as tobe water -tight are furnished with foot rests. When noin use they may be folded on their steel frames so as tofit into a small box for transportation. The pontoons maybe inflated and are provided with rudders for maintaining

a straight course.

Amphibious Toy

(Pat. No. 1,456.429, granted to Joseph L. Duggan.The body of this toy is made of light metal. It is fittedwith wheels, although it is built in the form of a boat.The spring motor it contains is connected to the wheelthrough a chain of gears and to an upright piece fastenedto the figure in the boat holding the oars. When on landthe boat is driven by the wheels; when it is in water theoars move it. Both the wheels and the oars move con-tinuously. The figure holdnig the oars is pivoted where itis attached to the seat in the boat. The oars are also

pivoted.



Scilentific lumorcMaybe He Will Meter There.-The

announcer at Broadcasting Station \YZ hadhad a hard day. Besides his duties as an-nouncer, he operates a Radio Supply Store.He had many things on his mind.

He was reading the news bulletin : "JohnDoe, who was arrested here last month ona charge of robbing the mails, was todaytransferred to the Federal Potentiometer.-Leslie J. Smith.

While Hydrogen Tans Hide.-.BOBBY :"Is oxygen what the oxen breathe all day ?"

PAPA: "Of course, and what most every-thing else breathes."

BOBBY : "And is nitrogen what everyonebreathes at night?" --Ed'w'ard Fleege.

The MissingLink . - BILL:"Why the gloomylook, Joe?"

JOE : "I'm introuble. My wifeoverheard m etelling SteveJackson that Ihad had t w omisses in my carthe evening be-fore."

BILL: "But that is no excuse for a row.Why everybody has engine trouble."

Joe: "But she found out that only one ofthem was in the engine." -147. A. Loveridge.

The Mechanics of It. -CRAWFORD:"There's an old fellow with a lot of jack."

CRABSHAW : "No wonder. He's a landlordand makes it jacking up rents."-J. J.O'Connell.

And We Must Pay $1.00 For TheseJokes.-MR. BROWN : "What's the idea ofthese china dishes on my radio?"

MRs. BROWN : "You ought to be glad Iput them there because you can tell Mr.Jones that you got China on your radio."-Jessie Walters.

A DelightfulJoke. - Invent-ors are nevertaken seriously.

No, even Edi-son made lightof his theories.Bradford Smith.

And the Arch of the Foot Is NeverBuilt.--WIsE ONE: "It's funny that thepupil of the eye never learns anything."

WISE Two: "Yes, and it's curious thatthe bridge of the nose is never crossed, andthe roof of the mouth never repaired.-J. Areuss.

Nutley, N. J., Papers Please Copy.-BILL: "That new automobile manufac-

tured by Jones and Company should provequite popular."

Tom: "How so?"BILL: "It requires only one nut."Tom: "How wonderful! But why not

eliminate all of them?"BILL: "Well, you see, one must sit be-

hind the steering wheel."-Rev. D. C. MacLeod.

A Ringer.-"It asks no questions, butyou have to answer it frequently."

"What is it?""A door bell."-Julia Gross.

-11't!.11111!IlliitilillrillIIIIIIIIIIIIItt1111111111,11!i11111111tIIIIMM11111111111111111111111111111E1IIIIIIIHMIIIV_,

tireproof.-SidneyP..iliwwwwfflummfflunimmuwwwwilitswElliiiiiiiiwwwfflummummuffliwwwwwwiiiii.

Ffirst Prize $3.00Most ofOurs Is.-L U N ATIC :

"I've inventeda coal thatwill last for-ever."

KEEPER :"How did youdo it?"

L U N ATIC:"I made it

Rochelson.

Ought to Be Sold by Stationery Stores.No 1 :. "They make engine wheels out of

paper now."No. 2: ''That so? Use them for station-

ery engines I suppose."-Everett Pardell.

A New Tune.-WIFE (to husband operat-ing new radio set) : "Henry, what are youturning all them black wheels for?"

HUSBAND: "Why, it needs tuning."WIFE: "Well that set can't be new if it

needs tuning already."-Karl L. Martin.

E receive daily front one totwo hundred contributions tothis department. Of these only

one or tzco are available. We desire topublish only scientific humor and allcontributions should -be original if pos-sible. Do not copy jokes from oldbooks or other publications as theyhave little or no chance here. By sci-entific humor 2t e mean only such jokesas contain something of a scientificnature. Note our prize winners. Writeeach joke on a separate sheet and signyour name and address to it. Writeonly on one side of sheet. No lettersacknozoledged unless postage is in-cluded.

All jokes published here are paid forat the rate of one dollar each, besidesthe first prize of three dollars for thebest jokes submitted each month. Inthe event that two people send in thesame joke so as to tie for the prize,then the sum of three dollars in cashwill be paid to each one.

En-light-ened.-"Law is -the oldest sub-ject matter in the college," said the law stu-dent, "because Adam was evicted from Para-dise for non-payment of rent."

"You are wrong," said the future doctor,"before that happened he was operated on."

"You arc both wrong said the electricalengineer, "before all of that happened, theLord pressed the button and said 'let therebe light."-Peter P. Udre.

Seeing ItThrough.-PROFESSOR (toSoph.) : "Explainthe difference be-tween transpar-ent, translucentand opaque."

S 0 P H : "Thewindows in thisbuilding wereonce transparent.

They are now translucent, and if they arenot washed pretty soon, they will be opaque."-Sadye Kauffman.

Why, of Course.-"With all due defer-ence my boy, I really think our Englishcustom at the telephone is better thansaying 'Hello!' as you do."

"What do you say in England?""We say: 'Are you there?' Then, of

course, if you are not there, there is nouse in going on with the conversation."-The Continent (Chicago).

The Saturday Evening GhostFATHER : "At last I've found a way to makethat young scamp of ours stop winking hiseyes."

MOTHER: "How?"FATHER : "I'll show him the article in this

Science Magazine where it says that everytime we wink we give the eye a bath."-Ilfrs. R. Rowe.

The Mock-Turtle.-Wrecked motor-ist at phone:"Send assistanceat once. I'veturned turtle."

Voice (fromthe other end):"My dear sir, thisis a garage. What

you want is anaquarium."-Julia Gross.

Eclipsed.-During the recent solareclipse so much publicity was attached withthe proposed flight of Army aviators in Cali-fornia to ascend 20,000 feet and take picturesin the path of totality, that around manynewspaper offices the eclipse was usuallythought of in connection with this flight.

About a week before the eclipse was due,a young newspaper reporter in Washingtonwhose education had been more literary thanscientific, telephoned the War Departmentand asked:

"Can I interview some one there who willgive me the details of this eclipse that theArmy Air Service is putting on out in Cali-fornia ?"-Ehait. C. P. IllcOarment.

A Case in theShort -CircuitCourt-A chapwas arrested forassault and bat-tery and broughtbefore the judge.

JuncE (to pris-oner) : "What isyour name, youroccupation a n dwhat are youcharged with?"

PRISONER : "My name is Sparks, I am anelectrician, and I am charged with battery."

JUDGE: "Officer, put this guy in a drycell."-The Inland Merchant.

Easing Up the Jar.-As Rastus was ledto the electric chair, an attendant asked himif he had a request to make.

"Well, boss," replied Rastus sadly, "Ahknows I'se goin' on a tough ride, and maybeI could use one of dese here shock absorb-ers !"-Chas.

And Seasickness.-TEACHER (to class inchemistry) : "What does sea water containbesides the sodium chloride we have men-tioned?"

SMART BOY: "Fish, sir."-James Rogers.


Science and Invention 'or January, 1924 901

44,4, Vi././744/.

A (--'1'1

.024cr 41:44,:14/7.4./.

The "Oracle" is for the sole benefit of all scientific students.Questions will be answered here for the benefit of all, but only matter of

sufficient interest will be published. Rules under which questions will beanswered:

1. Only three questions can be submitted to be answered.2. Only one side of sheet to be written on ; matter must be type-

written or else written in ink, no penciled matter considered.

3. Sketches, diagrams, etc.. must he on separate sheets. Questionsaddressed to the department cannot be answered by mail free of charge.

4. If a quick answer is desired by mail, a nominal charge of 25cents is made for each question. If the questions entail considerableresearch work or intricate calculations a special rate will be charged. Cor-respondents will be informed as to the fee before such questions arcanswered.

ARCHIMEDES PRINCIPLE(1599) Jesse Phillips, Philadelphia. l'a., asks:O. 1. If a cube of metal is suspended in a

liquid, is the pressure exerted upon it by theliquid equal in all directions?

A. I. Referring to the illustration herewith,faces A and B will be equally pressed upon in

The perpendicu-lar faces of ablock of any ma-terial suspendedin a liquid haveexerted thereonequal pressure.The pressure onthe upper facedepends on thedistance to "N"and that on thelower face onthis distance andthe thickness ofthe block.caurram,mm-rmmurmmun

opposite directions. It will also be found thatthe other pair of lateral faces will have the samepressure exerted thereon. On I), there will be adownward pressure equal to the weight of a col-umn of water whose base is the same size as faceD and whose height is equal to the distance fromI) to N. On the bottom of the cube, C, therewill be a pressure equal to the weight of a

whose base is of the area of Cand whose height is the distance of C to N.This is one of the principles of the mechanicsof fluids discovered by Archimedes and from itis deduced the fact that upward pressure on theimmersed body at any particular point is thesame as that on the fluid which it replaces.

TREATMENT OF CANCER WITH X-RAYS(1600) John W. Arnold, Urbana. Ill., asks:O. 1. Is a patient undergoing the X-ray treat-

ment for the cure of cancer likely to developother cancers from the use of the rays?

A. 1. With ordinary care a person subjectedto cancer treatment by X-ray does not developX-ray cancer. It is only those who work withthe rays continuously that are likely to become soafflicted, but with modern machines this possi-bility has been reduced to a negligible degree.In the olden days, when tubes were not shielded,such cases were rather frequent.

Radium rays can likewise cause a sort ofcancerous growth but the action of radium on anX-ray cancer case is very slight. The bestmethod of treatment of cancer today is excisioncombined with both radium emanation and X-raytreatment.

SOMETHING NEWCAN you build a telephone receiver less

than .3.4. of an inch big, or a loosecoupler, or a vario-coupler, or a variometer,or a radio outfit of this size? $200 in prizeswill be paid for actual working models ofthe smallest electric and radio apparatusand appliances. The most novel conteststaged in a long time. For full particulars,see page 951 of this issue.

This is only one of the big features of theslew and enlarged PRACTICAL ELEC.TRICS for January. Other features are:MEASURING CELESTIAL TEMPERA-TURESRADIUMAERIAL RAILROAD

By Raymond F. YatesANALOGIES AND OTHERS

By T. O'Conor Sloane, Ph.D.ELECTRIC TIMING OF HORSERACES

By Jacques Boyer, Paris Correspondent1 1 ,1 ,1 ,I i 111111

100 -WATT STEP-DOWN TRANSFORMER(1601) Jos. P. Rodriguez, New York City,

asks:Q. 1. Can you give me the necessary data for

building a step-down transformer giving 6 voltsat approximately 16 amperes on the secondary,to be operated on 110 volts A.C.?

A. 1. The illustration herewith gives all the

PRIMARY.- '700 TURNS OFN9.15 D.C.C.WIRE

SECONDARY. - 38 TURNSOF N.9..8 D.C.C.W1RE

At the left willbe seen construc-tional details fora 100 watt step-down transformerdelivering sixvolts at approxi-mately sixteenamperes on thesecondary. Thetwo coils shouldhe thoroughlyinsulated fromthe core.

411.111.111111111111111111111.1111111111111i

necessary data for such a transformer. The coreshould be built tip of laminated silicon steel andthe legs should he 1 inch square in cross-section.

REFLECTION OF LIGHT(160D John Harvey, Boston, Mass., wants to

know:

O. I. In speaking of the reflection of lightwhat is meant by the saying that "The angle ofincidence equals the angle of reflection?"

A. 1. The diagram herewith illustrates thisrule very clearly. The angle X is the angle of

Whenever a beamof light strikes areflecting sur-face, such as amirror, at a cer-tain angle, it isalways reflectedaway from thatsurface at anangle exactlyequivalent to thefirst. At theright, angles Xand Y are equal.

incidence and the angle Y is the angle of reflection. These two angles are equal in all casesof the reflection of light from a plain surface.

MOTH BALLS(1603) Mr. Norman Atkinson, Jordan, Minn.,

requests:Q. 1. Can you give me a formula for snaking

a preparation similar to that used in making mothballs?

A. 1. If you will melt together four ouncesof naphthaline and eight ounces of paraffine waxyou will have a production very similar to theordinary moth balls.

TROUBLE WITH FREEZING MIXTURES(1604) Anthony Azzopardi, New York City,

says that he used the freezing mixture mentionedin this department of this magazine some timeago which consists of ammonium chloride andpotassium nitrate. He says that with this hehas had no results. He asks:

Q. 1. Can you tell me why the freezing mix-ture does not work and give me some pointersfor using the same?

A. 1. It may be that your chemicals were in-sufficient in amount and for this reason your freez-ing mixture will not work. However, if the ini-tial temperature of the water used is about 32°C it will not freeze because the temperature de-pression of the mixture you mention is only30° C. Would advise you to try this mixtureagain using water with a temperature of about25° C, or even lower. If your chemicals arecorrect you should have no trouble in obtainingthe results you desire.

lr

Mr.

zuit su,c)(x) PRIZE CONTESTINVENTION. All you need to do is to keep your eyes open. Evenif you were totally deaf or blind. there would still he a way foryou to win a prize simply by using your head and sending usideas and suggestions of a scientific nature, or of a nature directlyor indirectly touching on new inventions.

YOU will note from this issue, our prize contest has gone overbig. Over $1.000 has heen paid this month for worth -while

contributions to this magazine, either in pictures, suggestions,ideas or articles. There is something doing all the time, nomatter where you live, that can he written up for SCIENCE AND

ARTICLES FOR FEBRUARY SCIENCE AND INVENTIONTaking Photos of the Earth with a Sky -rocketCamera By Raymond Francis YatesThe Secret of. Perpetual Youth

By Clement FezandieWhy the Elevation of Our Naval Guns ShouldBe Increased

By Graser Schornstheimer, Naval Expert TidesScience Serves in New York's Newest Hotel

Electricity and Science in Stock ExchangeOperationsA Day with America's Master Model Makers

By Joseph H. KrausA Gigantic Scheme for Utilizing Power of the

Announcement of Winners in the "SingleTube" Radio Receiving Set ContestThe Story of Lime By Ismar GinsbergDoes a Ship Sailing East Weigh Less ThanWhen Sailing West?Burning Coal Twice By Ismar GinsbergMatch Tricks --Second Article

By W. B. Arvin Choosing a Vocation by Machine Methods By Walter B. Gibson

eeeee

FREE INFORMATION.F you want additional information concerning any of the subjects illustrated and described in this number of SCIENCE AND INVENTION, we

Ishall be glad to give you other data we have at our command. To make this work as easy as possible for our editors, please be brief. Writeonly on one side of the paper and state exactly in a few words just what it is you desire further information on. We have the original manuscripts

and drawings of many of these articles in our files and can furnish much additional data in most cases. Please do not fail to send stamped andself-addressed envelope.

Address all inquiries of this nature to INFORMATION EDITOR c/o Science and Invention, 53 Park Place, New York City.


902

PERISCOPE PRINCIPLE(1605) John Blake, Vv'entham Mass., asks:Q. 1. Can you show, in simple form, the

principle of the reflecting periscope?A. 1. The illustration in these columns shows

the principle of the periscope and also how avery simple type may be constructed. A long

SLOT INBOX

MIRRO

11111111111.011111111111111111111111

A simple peri-scope may be

"'- made by usingtwo mirrorsplaced in an ob-long box at theangles illustrated.They can be heldby means of ad-hesive tape orglue. Slots areto be cut in thebox on oppositesides as illus-

trated.111i1111111111111111111111/1111111111111

narrow box of square cross -sec ion is obtainedand two mirrors fitted therein at the ends asillustrated. The surfaces of these mirrors mustbe parallel and the angles at which they areplaced will depend upon the location of the slotsin opposite sides of the box. This can best bedetermined by experiment. By looking in the slotat the bottom of the box, objects can be seenover other objects higher than the level of theeye by turning the periscpoe in the desired direc-tion.

MIRROR

SLOT INBOX

EYE

TRANSFERRING OF PICTURES(1606) Paul Redman, Kansas City, Mo., says

that he has seen a liquid which is supposed totransfer pictures from newspapers or magazinesmerely by coating the photograph with the li-quid and placing over it a clean sheet of paper.The illustration is then supposed to be trans-ferred to the clean sheet. He asks:

Q. 1. Can you give one any information onsuch a liquid?

A. 1. There have been various liquid solu-tions exploited on the market which the makersclaimed would transfer newspaper and magazine'print to plain paper. However, none of these havebeen found to give satisfactory results, and asan added drawback, the reproduced printing wasreversed. If you have any clippings or othermaterial which you desire to have reproduced,we would advise you to use the photostat meth-od.

2 M. F. CONDENSERS(1607) Richard Romaine, Iowa Falls, Iowa,asks:

Q. 1. Kindly give me the directions for mak-ing a 2 mf. condenser?

A. I. A 2mf. paraffin paper condenser wouldbe of too large a size for the average amateurto construct. This construction requires about 35feet of paraffin paper 4 or 5 inches wide, threeof these sheets being necesary. Two sheetsof tin foil, two inches shorter and inchnarrower than the paper, are also required. How-ever, trouble will almost always be experiencedin rolling this condenser up unless it is doneby machinery. These condensers can be pur-chased very cheaply from any electrical supplystore.

PNEUMATIC TIRE VALVES(1608) Robert Mellons, Canton, Ohio, wants

to know :Q. 1. What is the principle of the valve such

as used in the stems of ordinary pneumatic tires?A. 1. The illustration puts forth the construc-

tion of the standard type of tire valve. It willbe noticed that the valve proper is placed on acentral rod and held against its seat by a lightspring. Incoming air passes through the openingsindicated. The entire mechanism is so placed thatthe pressure of the air from the inside of the tire

I/ AIRRUBBER .4r ''"17 PASSAGE

1 ,41Cill 4 ESEAT

.$PRING i, a

i 0'STEM

GUIDE

,111.111111M1011,111111.1011M

The valve used inthe ordinarypneumatic tire isvery simple yetPositive in oper-ation. The pres-sure of the airwithin forces thevalve up againstthe seat therebysealing the airpassage and pre-venting the es-cape of air. Thespring is used totold the valve in

place.

IIINLIII(.111.11.1111l111111.1111..

forces the valve against the sea , thereby retain-ing the air in the tire. The spring used is ofsuch a tension that it will allow the incoming airfrom the pump or compressor to force the valveopen. The valve has its cap with rubber packing.This cap is screwed on by hand.

POTASSIUM PERMANGANATE(1609) Lewis Baldwin, Croton, N. Y., wants to

know:Q. 1. How may potassium permanganate be

made?A. 1. To make potassium permanganate, you

should fuse together equal parts of manganesebinoxide, caustic potash, and potassium chlorate.Dissolve the resultant in water and pass carbonicacid gas through the liquid. Filter, and thebright purple solution will be potassium per-manganate.

Q. 2. What js formed when hydrochloric acidacts on copper?

A. 2. Hydrochloric acid will act slowly on cop-per in the presence of air, forming cupric chloride.

9. 3. Will iron pyrites treated with sulphuricacid form hydrogen sulphide?

A. 3. No.

REDUCTION IN WEIGHT(1610) 0. Shimeton, Oakland, Cal., asks:Q. 1. If a piece of iron weighing three pounds

is placed in a vessel and the air exhausted there-from, will the vessel weigh three pounds heavierthan it would without the iron?

A. 1. If a piece of iron weighing three poundsis placed in a receptacle and the air exhaustedfrom the latter the entire weight will still bethree pounds more than the weight of the recep-acle alone. This is speaking approximately, forthe weight will be slightly less due to the weightof the air which was drawn out of the jar. Thiswould very slightly reduce the total weight.11111.1.1111711111f111,11111111,011111111,1111111111111111111.1M1:1111111111111,1111111P11111M111/11111111111,

IMPORTANTTO NEWSSTAND READERS

TN order to eliminate all waste and un-sold copies it has become necessary to

supply newsstand dealers only with the ac-tual number of copies for which they haveorders. This makes it advisable to placean order with your newsdealer, asking himto reserve a copy for you every month.Otherwise he will not be able to supplyyour copy. For your convenience, we areappending herewith a blank which we askyou to be good enough to fill in and handto your newsdealer. He will then be in aposition to supply copies to you regularlyevery month. If you are interested inreceiving your copy every month, do notfail to sign this blank. It costs you noth-ing to do so.

To Newsdealer

AddressPlease reserve for me copies of

SCIENCE & INVENTION every monthuntil I notify you otherwise, and greatlyoblige,

Name

Addressiiii 1111111111111.111111111111111119i111111111,1111111111.111t1.111111.1111111111111111111111111.1=11Y1112111U11.11111.1111MIIIM

AMMONIUMNITRATE

NITROUS081DE Nitrous oxide

may be preparedvery easily forexperimental pur-poses by settingup the apparatusas shown. Ni-trous oxide isgiven off by theapplication o fheat and col-

lected.

1111111.11 .$ t

NITROUS OXIDE(1611) Ralph Stevens, Brooklyn, N. Y., asks:Q. 1. How can nitrous oxide or laughing gas

be produced in small quantities in the chemicallaboratory?

A 1. The apparatus should be set up as illus-trated in the diagram herewith and a small quan-tity of nitrate of ammonium placed in a flask.Upon heating, it will be found that a gas is givenoff which gas will replace the water in the tallglass cylinder. Some will be lost by solution inthe water. This is nitrous oxide.

The nitrate of ammonium necessary for use inthis experiment can be bought; it is a regularcommercial product.

MOTOR LUBRICATION(1612) J. Simpson, Springdale, Pa., asks:Q. 1. How are the various parts of the aver-

age gasoline engine lubricated? That is, the wristpins, the crank pins and the cylinder walls andpistons?

A. 1. In the majority of internal combustionengines there are small channels in the crank caseat right angles to the line of the crank shaft. Into


these dip small oil scoops, one of which is locatedon the end of each connecting rod as illustratedherewith. These scoops throw the oil around in-side the crank case and, together with heat, forman oil vapor and spray which penetrates to everypart of the engin,. The oil also enters the small

QIIIIMIlirrn I r

The oil scoop il-lustrated at thebottom of theconnecting rod,shown in part atthe right, throwsoil around insidethe crank case ofa gasoline engineand lubricatesthe various mov-ing parts by whatis known as the"splash system."

oil hole shown in the illustration herewith, lubr'-casing the crank pin. This pin is also partiallylubricated by the hole placed by the oil scoop as

shown. The vapor and spray are continuouslyforming and keep in circulation throughout thevarious parts and lubricate all the sections ofthe engine mentioned in your question. It istermed splash feed.

CHARGING STORAGE "B" BATTERIES(1613) Edward Reynolds, Cazenovia, N. V.,

says that he has an airplane generator which willdeliver 13 volts at 33 amperes and wants toknow:

Q. 1. Can I charge a 22% volt storage "13"battery with this generator?

A. 1. We would not advise the use of theairplane generator you have for charging 22%volt "B" batteries. Its voltage is too low for thiswork unless you desire to charge your batteryin three different sections, which would of course,consume considerable time.

Q. 2. What is the proper speed for runningsuch a generator?

A. 2. Regarding the correct speed for runningyour generator, we would have to refer you tothe manufacturers.

GENERATOR QUERY(1614) E. V. Porter, Henniker, N. H., says

that he has a D. C. generator rated at 13 voltsand 33 amperes and desires to operate the samefrom a water power plant located 1,300 feet fromhis house. He asks:

Q. 1. What size wire should I use for con-ducting the current from the generator whichwill be located near the water power plant to thebuilding?

A. 1. If you will use No. 6 rubber coveredwire for conducting the current from your gen-erators to the house we believe you will have notrouble in lighting the buildings with the resultingcurrent. Of course, in order to insure stableoperation of the installation you should use astorage battery, to be charged by the generatorand which will deliver current to the house whenthe generator is not running.

SHIMS(1615) Jack Bartlett, Chicago, wants to

know :Q. 1. What are "shims" and of what use are

they in automobile engines?A. 1. A shim is usually made in a form such

as shown here and consists of many sheets of verythin copper lightly soldered together so that theleaves can be peeled off leaving a shim ofthe desired thickness. The leaves are usually oneone -thousandth of an inch thick. They are veryuseful in adjusting bearings to shafts if they areiteliit.i.rtrirrurfrIllorlomiltmuer

Very thin sheetsof copper, sol-dered lightly to-gether and cut asshown at thebottom of the il-lustration at theleft come invery handy whenadjusting c o n -netting rod bear-ings on automo-bile engines.They are knownas shims and oneor more areplaced as shown,so that the bush-ing and the con-necting rod mayhe made to fit

snugly.

11111111111.111111111111111111111111111111

placed in a manner such as illustrated herewith.As can be readily seen, the shims can be removedand peeled down to the required thickness so thatthe two halves of the bearing will fit snugly onthe shaft.



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The Man On the MeteorBy RAY CUMMINGS(Continued front page 859)

spired in me any emotion stronger than mypassions of hunger and thirst? Not so. Iwas in the full bloom of my manhood, yetthe sight of this beautiful woman thrilledme because now I knew instinctively I mightfind food and water.

I scrambled forward, holding myself tothe ground with difficulty, and entered themouth of her cave like some maraudinganimal seeking the sustenance I craved.

The cave -mouth gave into a tunnel leadingat an angle downward. The walls weresmooth. I forced myself down, half sliding,half gently falling. For an instant thethought came to me that I would encounterother living creatures-things to keep mefrom the food and drink I wanted. Had Imet them-humans or beasts-I know Ishould have fought desperately.

It was dark in the tunnel ; but soon I sawthat the rocks were glowing with a phos-phorescence. This grew brighter as I ad-vanced.

EXPLORATION

I went down perhaps two hundred feet;then the tunnel opened. I was in a subter-ranean chamber of indeterminate size, pos-sibly five hundred feet square, with a blackrocky ceiling some fifty feet above me. Thewhole place was dimly lighted by the red -silver glow which came from the rocks.The air was denser, with a pungent, aromaticodor. It seemed to strengthen me and clearmy head.

The sides of the cave were rough andbroken with overhanging rocks like shelves.Here and there were other small tunnel -mouths. Most important of all, a small sub-terranean stream crossed the cave, openingup into a little lagoon near the center. Itwas a thin -looking, milk -white fluid. I flungmyself down to it with a splash.

It tasted, not like milk, but like pure, coldwater, though very thin and light. I drankmy fill. The joy of it I

There was a pile of blue fabric-wovengrass-on the bank beside the stream. Thegirl's couch, it proved to be. The robes werevery soft, gossamer in weight. I started todry myself upon one of them. But thewater-I shall call it that-evaporated likealcohol, and I was dry in a moment.

There was food here. A patch of blacksoil had queer, fungus-like growths in it.I had no doubt it was the girl's food. Therewere the remains of a fire, though I did notknow what it was at the time. On a stonewas some of the fungus which had beencooked. Of this I ate.

Upon the couch I lay at ease. Theblue robes lay around me like swan's down.My slight weight made me seem floating inthem. It was my first conscious momentof physical peace.

With hunger and thirst appeased mythoughts turned to the girl. She was notonly the first woman, but, to my memory, thefirst living thing I had ever seen. Wherewas she now? Could I capture her?

Across the cave I saw something move.The mouth of a passage -way was there be-yond the stream; and in the dim glow oflight I could make out the girl standingthere. She was watching me as I lay inpossession of her couch.

I held myself motionless. After a momentshe began coming forWird, timidly, yet cur-iously to inspect me. She stopped at theedge of the stream no more than fifty feet

away. Her hair fell in waves to her knees.She stood hesitating, frightened, yet drawnby a power greater than her fear, I couldsee the muscles of her limbs tensed for in-stant flight.

I had intended to leap suddenly acrossthe stream but a strange shyness came overme. Instead, I called to her. Words? I hadno spoken language. I called some syllable.It startled her; but she answered-a softlittle call of shy friendliness.

I wanted her to come to my side of thestream, but she would not. I beckoned toher; but she moved backward on fairy-liketip -toed steps. It angered me. I waved myarm vehemently and tried to climb to myfeet, struggling with the airy, half -floatingrobes of the couch.

The girl took flight. Her arms struckout, and like a swimmer mounting throughwater she floated up to the ceiling, landingupon a ledge of rock. Through a tangle ofher hair her face peered down at me. Andthough her eyes were frightened, thereseemed an impish, mocking expression to hertremulous smile.

Shyness dropped from me. She wouldobey me; I would make her. I kicked my-self into the air and swam as I had seenher swim. But it was not as easy as itlooked. I turned over in the air, losing mybalance in spite of myself.

THE CHASEI reached the ledge, striking my shoulder

violently upon it as I landed in a heap. Butshe was not there. Across the cave, downby the couch she stood poised on tip -toe,looking at me. And this time her red mouthand dancing eyes were openly mocking.

For half an hour I pursued her about thecave; but she eluded me as easily as thoughshe had been a butterfly and I one of yourEarth -children in eager chase. She couldhave escaped from the cave, but she had nofear of me now. At last, bruised and ex-hausted by my futile efforts, I sank upon hercouch; and again she stood nearby, regard-ing me.

I was angry and sulky. I pretended to dis-regard her. At last, utterly worn out, I fellasleep.

IVWhen I awoke, the girl was sitting beside

me. Her soft fingers had been stroking myhair ; it was their touch which awakened me.As I moved and opened my eyes, she instant-ly withdrew beyond my reach.

I was hungry again and when I motionedto her and indicated the food, she seemedto understand. I sat quite still, and withina few minutes she was deftly preparing ameal. But I was aware that she watched menarrowly and seldom came within my reach.

The fire she produced by rubbing twostones together. It seemed to ignite thestones, with a tiny flickering flame like theburning of sulphur. She had gathered a pileof dried vegetation from the surface abovethe cave; and when that was blazing sheadded rocks that glowed like coal. The fireinterested me tremendously. It alarmed me:but only at first, for I saw that the girl hadno fear of it.

I need not go into details. Her mannerwas proud when presently she indicated thehot food ready to eat and she watched meexpectantly while I tasted it. I smiled myapproval and beckoned her to take some ofit with me. At which she curled up on the




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The Man e the Meteor(Continued from page 904)

robe beside me, eating the food I pushedtoward her.

We were friends. Like myself, she hadno spoken language. But when we tried totalk it came fast. I indicated myself andtold her I was Nemo. The word seemedto spring readily to my mind; I have nodoubt it was some part of my earlier life.She had no name. I called her Nona. Itseemed to please her. She repeated it afterme half a dozen times, and clapped herhands delightedly.

LEARNING TO TRAVELA little later we went up to the surface

of our tiny world. It chanced to be day-light ; and Nona taught me how to swimthrough the air, how to handle myselfagainst this lack of gravity.

The art came to me quickly. I was soonable to swim about with swift, powerfulstrokes. My stronger muscles gave me anadvantage over her. I could swim morequickly; but I could never attain her deft-ness, her agility. She would swoop about,dive head downward in a graceful arc, rightherself and land on tip -toe.

We circled our little globe, swimming atan altitude of a hundred feet, and followingthe Sun; and within half an hour were backat our starting point. Everywhere I saw thesame bleak landscape. It was night whenwe returned, for we had overtaken the Sunand passed it. But in a few moments day-light came again.

Then Nona showed me how to jump,.With arms folded, she leaped vertically intothe air. Straight up her body shot, her hair

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brushed flat against her by the downwardrush of wind. She held herself upright bythrowing out a hand occasionally. Like anarrow she mounted; until standing on theground I could see her only as a tiny darkspeck against the blue of the sky.

She came swimming down a few momentslater, her hair waving like a cloak behindher, spun gold with the sunlight on it. Shewas laughing and flushed from the exertion.

Then at arms length with fingers clasped,we leaped upward together. The tiny worlddropped away. Looking down, it showeditself as a ball. I could see far around it.

We seemed to mount endlessly. The airgrew so rare I gasped for breath. My headwas roaring. I was cold. Below, I couldsee the spherical meteor turning under us.We were in Space, no longer a part of ourworld. And we had almost reached the limitof its atmosphere.

Nona's fingers clutched mine tightly. Sud-denly she twisted me downward and droppedme. A strong side wind had sprung up.We swam down against it, fighting our wayuntil at last we were back to the meteor'ssurface.

I was tired, for through my clumsinessI had used far more energy than Nona;but I would not let her see it. I saw herlook upon the muscles of my arms andshoulders, and her admiration pleased me.I stretched my arms for her, showed her themuscles of my legs; and looked about forsome way of displaying my prowess. Therewere many boulders around that could beloosened. One by one I flung them intothe air, sent them into Space never toreturn.

MOVING MOUNTAINSNona watched me with awe, encouraging

me with little syllables of pleasure as I se-lected larger and larger rocks. Some I dugup and tore loose, until at last I ripped offthe top and side of a hill. It was a moun-tain of rock. I staggered like Atlas, withit over my head, and then launched it intothe air. It rose a short distance, and fellback to form another hill.

Nona gazed at me with new respect andwith a look in her eyes that made my heartpound. I was casting about for some largerburden, but she drew me away.

I was pleased. A sense of my own powerfilled me. I was master here on this worldof mine. I could have taken it apart bit bybit and tossed it into Space. I could teardown mountains, build others in their stead.

Facts and figures? I am in a position nowto give them to you. My meteor had a diam-eter of five miles, a circumference of somefifteen. Its density relative to Earth was.67. Its surface gravity-again relative toyour Earth-was .00039 placing Earth as 1.00.My weight at the surface of my meteor-neglecting other factors which I shall namein a moment-was slightly over one ounce.

Without undue exertion I could leap up-ward nearly ten thousand feet-that is tosay, almost two miles. And the mountainof rock I tossed into the air on your Earthwould have weighed some 320,000 pounds!

I have said that the boulders I tossed up-ward left the surface of the meteor neverto return. At an initial velocity of 13 feeta second, all objects became satellites of themeteor, revolving about it comparativelyclose to the surface in perfect circles. Thevelocity of escape was but 18% feet a sec-ond, i.e., that velocity which would causean Object to pass into outer Space, movingonward until it found some larger body toencircle.



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The Man on the Meteor(Continued from page 906)

1.1.11.111M11.1.1.1.1.11.11.1.111111111.11.4114111111111101111111111111111111:1111111111111111111111/111111111111111.

I give these figures without correctionsfor atmosphere, axial rotation of the meteor,or the attraction of other bodies. Theoret-ically they are accurate, though in practicethey were altered somewhat. During ourbrief days we weighed more than I havestated ; while at night, less. Indeed, had weessayed to jump into the air at night, weshould doubtless have been unable to strug-gle our way back.

How can that be, you ask? Our proximityto Saturn ! Around this great planet wewere revolving at a distance of no morethan thirty-five thousand miles. Saturn'ssurface gravity is a trifle greater than thatof your Earth -1.07 to be exact. Saturn'sdensity is only one -ninth that of the Earth;but the difference is made up because of itstremendous size. Saturn's gravity-to uson the meteor-was an appreciable pull,even though diminished by the distance be-tween us, and further offset by the meteor'srapid rotation.

Thus, you see, when Saturn was below us-in daytime-its gravity was added to ours.But at night, when it was in the sky above,it was subtracted.

These conditions applied to the days I amdescribing. Our meteor was then betweenSaturn and the Sun. Later in our year,when we had passed around Saturn, theSun was blotted out. There was then nodaylight-merely alternate periods of a skyfilled with Saturn's silver disk and the azure,star -filled outer Space.

I have not mentioned the time of ourmeteor's axial rotation. It was, as you onEarth measure time, 2 hours, 58 minutes.A complete day and night in less than threehours!

GLORIOUS NIGHT

When I had finished showing Nona mystrength, it was night again. And such anight! Saturn no more than thirty-fivethousand miles away ! The darkened bandswere plainly visible. When fully overhead,the circular limb of the planet came downin all directions almost to our horizon. Thesilver light from it was dazzling. Andeverywhere in the sky, meteors like ourselveswere whirling past-silver in Space, flamingred when fragments of them struck our at-mosphere.

Occasionally a meteorite would strike oursurface, but we had no fear of them. For anhour perhaps, we stood together, silent, gaz-ing with awe at these mysteries of the sky.Until at last Nona gently drew me backto her cave.

V

Within the cave the air seemed warmerthan before perhaps because I was flushedand tired from my exertion. The radiantlight from the rocks was soft. Here all wasquiet and peace.

At once I threw myself upon Nona'scouch, stretching my limbs, head pillowedupon my crooked arm. For a time, as beforeshe stood regarding me. There was in hergaze now no fear, but a curious softness.I sensed it. With sudden thought she smiled,and swam across the cave. She got a stone,hollowed out like a cup. She filled it at thestream and offered it to me. I drank grate-fully.

Again I was conscious of hunger. Thefungus-like food was unsatisfying. I madeNona understand, and she seemed distressed.I could see she wanted to feed me but hadno other food.

Finally she motioned me to lie quiet. Iwatched her as she stretched herself prone

1.1.11111111bilii.

on the ground near me. Her head wasraised ; she was looking keenly, carefullyabout the cave. Then she began swimming,slowly, stealthily no more than a foot or twcabove the cave floor circling about, up alongthe walls, back overhead following the lineof the ceiling.

Once, when she was hovering over by theside wall, I saw her grow suddenly alert. Ifollowed her steady gaze; and on a rock fiftyfeet from her I made out the outlines ofsomething lying motionless. It was the exactcolor of the rock itself. It looked like alizard some three feet long, with white eyesstanding out from its forehead. It was be-cause of the eyes that I first saw it.

Nona was in midair. Then, like a waspshe darted at that thing on the rock.

MEAT FOR FOODThe lizard-I shall call it that-saw her

coming. It leaped, and sailed across thecave. I saw that it had webbed membranesconnecting its six outstretched legs.

Nona turned in the air after it, her slimbody as sinuous as her waving hair itself.She was faster than the lizard, but again,on the opposite side of the cave, it eludedher.

Back and forth across the cave they went.Often the reptile would dash for one of thepassageways but Nona with her greater in-telligence, always anticipated it and wasthere to bar its way.

The lizard seemed jointed all over, and itcould turn in the air with extraordinaryswiftness. But not so swift as Nona. Oncethe reptile whirled back and forth on a sus-tained flight. Nona followed its every twistand turn as one bird follows another.

At last she had it in her arms, in jnidairat the center of the cave. Calling to me intriumph, she struggled with it, fighting herway down to the ground.

I started toward her, but her voice andgesture waved me away. The lizard wasscreaming-a shrill, hideous scream. But shehad its back bent across her knee. Its spinebroke with a crack. It lay still.

By one foreleg she held its quiveringbody up to me ; she was laughing with hap-piness as she sought my applause.

We ate the meat of its tail and legs; andsatiated, I lay somnolent on the robes andwatched Nona moving about the cave. Sheextinguished the fire, and at last approachedme timidly. I did not notice her. My eyeswere half closed. I was vaguely planningmy own hunting for food-wondering ifthere would be other reptiles larger, for meto capture.

A twitch at the coverings on which I waslying aroused me. Nona was pulling a robeout from under me for herself. I pushed ittoward her.

I did not move. It was very soundless inthe cave with only the murmuring of thestream. Nona curled up on her robe nearme. Thus we lay silent; but I felt her shygaze always upon me and suddenly I cameback to complete wakefulness.

We stared wordlessly at each other untilher gaze timidly dropped. With heartracing, I moved myself slowly toward her.I was afraid to frighten her; but she moved,not away, but to me. Abruptly my armswere around her.

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The Man on the Meteor(Continued from page 908)

VINOTE TO READER

The foregoing manuscript was written byan old man-known only as Nemo-who isat present an inmate of one of our StateHomes for the Aged. His case is a curiousone. The Institute authorities inform methat two years ago he was found wanderingon the streets of Chicago, the victim, appar-ently, of amnesia. He had no idea who hewas, nor could he give any details of hispast life. No papers of identification werefound upon him.

I talked with the old man personally forsome hours. He is undoubtedly cultured, andwith a wide, though eccentric scientificknowledge. He speaks English with an ex-traordinary indefinable foreign accent-anaccent which leaves one wholly in doubt asto his possible nationality.- His memory has never returned. No trace

of friends or relatives has been found. Atthe Institution, because of his pleading, he isknown simply as Nemo.

Though the events of his later lite are

still a blank, Nemo insists that he can re-member, with a clarity which increases daily,the events of his youth. The authoritiesscoff ; they tell me he was doubtless at onetime some obscure scientist, possibly ofEurope. Efforts are being made to identifyhim.

You have read Nemo's written narrativeof his first conscious memories. He gave itto me at my request ; and with a cynicismfor which I cannot blame him, assured methat no one would credit it. I have madealmost no changes; you have it practicallyas he wrote it.

For myself, I liked the old man. His per-sonality is distinctly likable, and his mannerconvincing. I can testify that his sole ap-pearance of irrationality lies in the extraor-dinary things he has to tell. And in thesepresent days of science when nothing seemswholly impossible-and when, as alwaysthrough history, the thoughtless find iteasiest to scoff-I can offer no opinion. Ileave you to be his judge.

RAY CUM MINGS.

Dr. ackensaw's secretsBy CLEMENT FEZANDIg

(Continued from page 861)LuolumulitU1111111.1mIlimuctrantrummumMillnintimullinunumunlmsumtm.,...........1.1111m,.

they found themselves in a small closedchamber. A door in this chamber immedi-ately opened and gave access into a streetof Submarina.

"You see, Silas," remarked Doctor Hack-ensaw, "we're pretty safe here. Even if anenemy discovered our hiding place, he wouldfind it difficult to injure us. We couldeasily protect ourselves against attacks fromsubmarines, and I doubt if even depth bombscould do us much damage. In fact the wholecity, like a ship, is built in air -tight compart-ments. If one is damaged we can takerefuge in another. The central city is somedistance away. In fact we must take theelectric trolley car to get there."

"What !" cried the reporter, amazed. "Atrolley car here, under the ocean ?"

"Of course. You don't suppose I am go-ing to give my men any more work than isnecessary. Every labor-saving device I canthink of is installed here."

THE SUB -SEA CITYIt did not take Silas long to realize that

he had come to a real city. The streets,lighted by diffused electric light, were asbright as if the sun were shining overhead.They bore names and numbers, and werekept spotlessly clean. The air was pure andsweet-a regular ocean breeze pervading.

"How is it the air here is not under pres-sure?" asked Silas. "I understood that theair pressure on the earth is about 15 poundsto the square inch. Every thirty-two feetdepth of water adds 15 pounds more. Hencehalf a mile under water the pressure shouldbe 1,252/2 pounds per square inch."

"You are right about the water pressure,Silas, but my air taken from the sea levelhas barely little more weight than normalair. Half a mile more of air in the columndoes not greatly increase the weight."

"But how do your receiving chambers andthe roof of your city stand the enormouswater pressure?"

"My receiving chambers and my entrancewells have thick walls of the strongest metalsI can obtain. The city itself is excavatedso far under ground that there is little dan-

11111111111111,1i11111.1miliwilliiiiiiiltoilm111111111111111:1111.11.111111111.11.111.11111.11.111111111111.111.111111111111

ger. You will notice that the car is goingdown a rather steep incline."

To say that Silas was amazed would be toput the matter mildly! He could scarcely be-lieve his eyes as he went from one surpriseto another. The streets were filled, not onlywith laborers, but with clerks, stenographersand other professional people, and evenwith children. Theatres, moving -pictureshows, restaurants and ball rooms advertisedtheir various attractions. There was a bank,and there were even stores, but, as the doc-tor explained to Silas, all the stores and rec-reation centers were under his own manage-ment and were run at cost. The storeswould furnish anything wanted, sending toEngland for it if necessary. Only two thingswere noticeably different from the ordinarycity-here there were no automobiles and nohorses

BOTH WERE TABOOEDSilas was deeply impressed. "I wondered

how it was," said he, "that you were ableto get help in your submarine city, but nowthat I have seen it, I am not surprised.Your workmen have all the comforts ofhome here."

"Yes, we receive all the principal books,newspapers and magazines, and we evenpublish a journal of our own. 'The Sub-marine Daily Swash.' We have telephonesand electric lights and all modern conveni-ences in every house, even including radioreceiving sets to receive the `broadcasts' fromEngland. But here we are at the oil wells.Let's get out and visit them."

THE OIL WELLS"How do you dispose of your crude oil?""I have a secret pipe line which carries

it to an English refinery I have started. Wealso refine oil from Europe, though ourgreatest supply comes from here. I furnishgasoline to England and France cheaperthan any one else can supply it. My onlydoubt is whether or not I am benefitting theworld by so doing."

don't understand you.""What I mean to say is that I am a firm




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(Continued from page 910)Et11111111:1111111111111111111111111111111111111111111111111111.11.11.11=1.11111101111.

believer in the conservation of natural re-sources. It has taken Nature millions ofyears to store up her supplies of coal andpetroleum, and there is no hope of thembeing renewed. It seems a wanton waste touse these up for pleasure trips in automo-biles. We ought to make use of alcohol orair or water -power or some other such in-exhaustible source of energy, instead of con-suming these invaluable natural hydrocar-bons. My only consolation is that chemistryis making such rapid strides at the presentday, that the time is bound to come whenwe can make the petroleum products syn-thetically, 'from carbon dioxide and water.'"

Have you had a coal mine here?""Yes, and a very rich one. We are work-

ing it now. As soon as I perfect my devicesfor burning the coal without smoke, I shallgenerate all my own power here and shallthen send electrical power by cable to Eng-land. 'Turn about is fair play.' Up to date,I have placed the coal, as mined, in largebuoyant steel vessels, hermetically closed,allowed them to float to the surface and thentowed them to some convenient spot wherethe water is smooth where the coal can betransferred. to ships."

"Your city ought to be useful as a sub-marine base in war time," suggested Silas.

"Yes, indeed, especially as its existence isnot suspected."

"I don't see how you can keep it secret.""All my help are under contract to remain

here five years. Only those I know I cantrust are allowed to attend getting suppliesand provisions. Of course, Submarina could,in a pinch, furnish all her own food; asfish, oysters and seaweeds of many kindsabound. But I find it easier to import meat,flour, and vegetables rather than attempt toraise them here."

"How could you raise wheat here, withoutsunlight ?"

THE MUSEUM"I think it could be done by means of ar-

tificial light, but until I manufacture myown electricity I shall not do any experi-menting in this line. But here we are at theMuseum. Come in with me and I'll showyou some of the curiosities we have discov-ered in the ocean's depths. Here are per-fect specimens of all kinds of marine plantsand animals, specimens such as you will notfind in any museum on earth, for my mengo out in diving suits and select only thefinest specimens. My workers are free tomove about as they use my artificial gillsto furnish them air for breathing. Thenhere are relics from sunken ships. Thesecoins and jewels came from a Roman galleythat sank here hundreds of years ago, andwas deeply imbedded in the silt. We comeacross very curious things here."

The journey was continued and Silas wasshown one new marvel after another. Noth-ing that might lend to comfort or recreationof the inhabitant was neglected.

The pair stopped at a restaurant and hadan excellent dinner, and then took rooms inthe hotel-for a hotel had been found aconvenience for many, especially those en-gaged in the transportation of supplies. But,in the middle of the night, Silas Rockett wasawakened by the loud ringing of an alarm.An instant later, Doctor Hackensaw, in hisnightshirt, was at the door.

"Grab your clothes, quick!" he cried, "andcome with me ! Submarina has sprung aleak!"


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HOW I SAVED MY HAIR!THE TRAGEDY OF BALDNESS

WHEN the barber told me my hairwas getting thin I merely smiledand let it go at that. When mywife said, "Bert, I do believe you

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Dr. Hackensaw'sSecrets

(Continued from page 912):,,,,11111111111111111111111111111111111111111111 ===== 1111111111Y11111111111111111111111111111111111111111110111111111111V1111111110-,

Silas Rockett lost no time. He made onegrab for his clothing and then followed thedoctor out into the street where they foundnumbers of lightly clad men, women andchildren splashing through a small stream ofwater that had suddenly made its appearance.Among the number was a woman with ababy in her arms-the first child born inSubmarina.

"Follow the water !" cried the doctor, andSilas obeyed. He realized only too well whathad happened. The enormous pressure ex-erted by the ocean above, had caused theearth, that formed the roof of the city, tocave in at some spot, and it was evidentlybut a matter of minutes before the flyingpeople would all be drowned like rats in at rap.

"Good bye, doctor," cried Silas, but thedoctor did not hear him. Meanwhile thestream had rapidly risen and the water nowreached their knees.

"Grab a life preserver!" cried the doctor.Silas now noticed that life preservers in

large numbers were hanging within reach, onthe sides of the houses. Evidently an emer-gency like the present one had been fore-seen and prepared for, and the reporter'sspirits rose. The fleeing crowd were allbusily engaged in putting on their life pre-servers, and Silas and the doctor were not amoment too soon in adjusting theirs. Evi-dently a new portion of the roof had givenway, for the water came pouring in, andthe stream became so rapid, they were bornealong at a terrific pace.

TO SAFETY

"Put on your helmet I" commanded thedoctor.

To each life preserver a helmet containinga reservoir of compressed air was fastened.Provision had of course been made so thatthe air would be reduced to normal atmos-pheric pressure before being inhaled.

Silas lost no time in adjusting his head-piece, and, before he got it on, he realizedthe need of this protection, for the air in thestreet, compressed by the inflowing water,attained a pressure which made breathingdifficult. It is a sudden change of pressurelike this, that in under -water caissons, givesworkmen attacks of "the bends."

At this moment a shriek from the womanwith the baby called their attention to thefact that the mother burdened with the childhad been unable to provide herself withlife preservers or helmets. It was onlywith the greatest difficulty that Silas andthe doctor managed to secure helmets forthe two, and get the pair safely protected.

By this time the water was so high thateveryone was afloat, borne rapidly forwardby the swift current. Luckily their journeywas nearly finished, for they came suddenlyto the end of the passage where about athousand persons were floating about, await-ing their turn to pass through a revolvingdoor somewhat similar to those used in de-partment stores.

The purpose of these doors was soon evi-dent. Doctor Hackensaw, in planning Sub -marina, had foreseen the possibility of acatastrophe like the present one, and hadbuilt his city in water -tight compartments,like our modern trans -Atlantic liners. Theocean might burst its way into one of thesecompartments, but the inhabitants could takerefuge in the others.

Communication between the compartmentswas made by means of revolving doors. Oneach side of the door was a completely en-


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Dr. Iffackensaw'sSecrets

(Continued from page 914)

closed platform hermetically tight, whichheld one hundred persons. Revolving thisplatform half way, brought it safely to thenext unflooded portion of the city-the smallamount of water in which the persons floatedwas of course carried with them, but wasof no consequence.

While Silas and the doctor were waitingfor their turn to pass through the door, thedoctor showed the reporter an iron gratingthrough which the ocean water was descend-ing into an unused mine -shaft.

"You see," he explained, "I constructedmy door here, in order that the current ofwater, flowing down into this shaft, shouldcarry all refugees safely to this spot-theonly place where safety lies."

Silas admired the ingenuity of the scheme,but he was shivering with the cold and gladto get somewhere where he could obtain dryclothing. But he had had enough of sub-marine cities, and when the doctor suggestedreturning to London, he acquiesced withalacrity.

"Submarine cities are very interesting,"said he, "and they offer some novel experi-ences, but as for me, give me the sunlightand the open air !"

Correct Postures forVarious Workers

The ill effects causedby the strain onworkers who a r eforced to hold oneposition for hour onhour on account ofthe nature of theirwork or of the ma-chine they operatehas long been known.The U. S. Depart-ment of Health isconducting a cam-paign for the relief

of this condition. Intheir circular letter"DBF," some of themost harmful of thepositions are illus-trated and remediessuggested. At theleft is shown one ofthe most harmful.The woman at themachine is forced tostand with one sideof her body contract-ed and the other

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When workers are forced to sit on chairs too high to admitthe feet touching the floor, a foot -rest on the order ofthe one shown above should be provided. If it is not,

fatigue will result.


Science and Invention for January, 1924MMTIMP11/111111111 frItrrrnI/m rmrm 11E, 77111/111TIIIT1.11114

The Heavens inJanuary

By ISABEL M. LEWIS, M. A.(Continued from page 878)

lllll

ual Orion or "helium" type as its bluish -white light indicates. The three evenlyspaced stars that mark the Belt of Orionand the two stars Saiph and Bellatrix thatform, with Betelgeuse and Rigel, the hugequadilateral that outline the body of Orionare all second -magnitude stars. No otherconstellation contains so many brilliant starsor so many objects of exceptional interest.Most of the brightest stars in the group areeither double or multiple stars and the pos-sessor of a small telescope will find this arich field to explore. The line of faint starsto the west of the quadrilateral representsthe lion's skin that is flung over the leftshoulder of Orion while the line of faintstars running northward from Betelgeuseand then turning sharply to the westwardrepresents the uplifted arm of Orion andthe club that he is brandishing. Its tip liesclose to the horns of Taurus. Betelgeusewhich is Arabic for armpit, is the star inthe right shoulder of Orion.

It was the first star to be measured withthe Michelson interferometer and its diameteris about two hundred and seventy-five timesthat of the sun. As to its distance from theearth there is some uncertainty but it isprobably between one hundred and fifty andtwo hundred light years. In addition to itsinterest as a giant star, Betelgeuse is an ir-regularly variable star by as much as half amagnitude The cause of its light varia-tions are so far unexplained.

Close at the heels of Orion follow the twodogs, Canis Major and Canis Minor. Sirius,the brightest star in the heavens and one ofthe nearest stars-only eight and three-fourths light years away-is the principalstarin Canis Major.

Venus is now a beautiful object in thewest at sunset but sets about two hoursafter the sun. It is gradually approachingthe earth and is slowly increasing in bright-ness. Mars, Jupiter and Saturn will all befound in the eastern sky before sunrise. Itwill be spring before they will be seen inthe evening hours.

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The Month's, ras cooksA digest of the general scientific publica-

tions issued during that period,with brief criticism.

THE OUTLINE OF SCIENCE. In fourvolumes. By J. Arthur Thompson. 1220pages, profusely illustrated. Board. G. P.Putman's Sons, New York.It would be one of the most profitable steps

ever taken in education if the plan of the book-and the book itself, for that matter-were madea compulsory study in every college course. Thefirst chapters of the work are given over to abrief survey of the universe and how the earthcame into existence. Then follows a discussonof the theory of evolution and the ascent of manover the mammals and reptiles. Being written inthe paragraphed form, it is very easily understoodand the continuity of the discusson and the pre-sentation of facts is clear and concise.

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Following this, at the beginning of the thirdvolume, comes a chapter under the name of SirOliver Lodge on "Psychic Science," in which thefamous Englishman presents his views. The factsare merely presented, the reader is asked to takenothing for granted. He may take it or leave it,according to his own opinion.

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The work is printed in large type and its pro-fuse illustrations lead to ease of assimilation ofideas, some of which may be new to the reader.The fact that it takes up the science of the worldin its logical order and inter -relates all branchesof it, makes it very valuable. Everyone interestedin science should read it, if, for no other reason,than because it will help greatly to classify themaze of information he may collect on scientificsubjects. It will organize his knowledge.

THE GLANDS REGULATING PER-SONALITY. By Louis Berman, M. D.,Associate in Biological Chemistry, Colum-bia Universty. Cloth. 300 pages. TheMacMillan Co., N. Y.Although a great deal that is bizarre and a lot

more that is idiotic has been said about the glandsof internal secretion, lately, in connecton withthe so-called youth restoring operations, there isnothing but close scientific discussion in thisbook. There is a short introduction on the gen-eral attitude toward human nature leading to adiscussion of how the glands affect it. A shorthistory of the discovery of the ductless glandsfollows and the research finally leading to thediscovery of their important relation to the form-ation of character is described.

The thyroid and pituitary glands (the twomost important of the ductless glands) are dis-cussed. Here the situation, fluid of secretion,and their place in the scheme of evolution arecommented upon. In each case, data, experi-ments and theory concerning them are set downin the manner of a scientist. There is nothingof the florid journalistic craze about the treat-ment of the subject.

Finally, toward the latter part of the book, agreat many of the characters of history are dis-cussed in relation to their glandular equipment-a new light in which to analyze the brilliant menof the world, possibly, but one that explainsthem quite thoroughly and accounts for manyof their shortcomings and failures that otherwisehave to be credited to "human nature."

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Now we are on the eve of a great awakening. Ourheritage from the World War has been an intense devel-opment of the chemical industries in the United Statesand a tremendous interest In all the applications of

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Remember that you do not need to study ChemtstrYwith the idea of actually practicing as a chemist, al-though a great many of our students are taking ourcourse with this object In view. If you want to , knowmore about what Chemistry will do for you, if you wantto know what our home study course offers. sign andmall the coupon today for FREE BOOR "Opportunitiesfor Chemists."

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FUNDAMENTALS OF RADIO. By J.L. Thomas. 207 pages, illustrated. Board.D. Van Nostrand Co., New York.Beginning with a chapter that is called "Reviewof the Principles of Radio," the author explainsvery tersely, but in terms perfectly understand.

able to those who have the amateur's knowledgeof electricity, the primary laws of radio. Fol-lowing this, instruments and methods of measure-ment are taken up. The style of the book is conciseand clear throughout, giving the reader the factsunadorned. There is no trouble in understandingthe principles set out. Following the chapter onmeasurements he goes on through the theory ofcapacity and inductance and then into the prin-ciples of transmission and reception of signals.The book is very complete with tables and glos-sary, making it exceptionally valuable for theyoung amateur.

RELATIVITY AND MODERN PHY-SICS. By George David Birkhoff andRudolph Ernest Langer. Cloth, 283 pages.Harvard University Press, Cambridge,Mass.Here we have a mathematical treatise on therelations of the Einstein theory to modern and

classical physics. Although the two college pro-fessors who are its authors definitely assert inthe preface that the minimum of technical matteris used in its presentation, the book, nevertheless,is composed by building one formula on another.The chief work of the book is a postulation oftime and space in such a manner as to be aworking basis for both the Einsteinian and clas-sical theories.

The latter part of the book is given up to adiscussion of various points of the two theoriesin connection with the problems of gravitation.

FUEL OIL IN INDUSTRY. By Stephen0. Andros. Cloth, 198 pages. PetroleumExtension University, Fort Wyane, Ind.With the ever increasing vicissitudes that arebesetting tire coal industry and making the fuel

supply for industries, as well as for householders,more and more hazardous, oil as a fuel is corn-ing very much to the fore.

This little book discusses the problems of com-bustion and shows how commercial needs may besatisfied with oil fuel. Beginning with a sort ofelementary treatise on combustion-inserted so theproblems treated later in the hook may be morethoroughly understood-the author passes on intothe field of heavy oil as a fuel. There arechapters on the heat content of oil, the makingof tests to ascertain the correct amount of airto be used with it and the correct design of fire-box in which the oil is to be burned.

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This is the second edition of the book, rewrittenand revised on account of the new factors addedto the problem by constant fluctuation and almostever-present instability of the coal market.

THE TYRANNY OF GOD. By JosephLewis. Board, 122 pages. Published bythe Truth Publishing Co., New York.This little volume directed against God andNature is quite the silliest, inane thing that hascome to the attention of this department inmonths. Not that the reviewer is not open minded

to any system of proof. Quite the contrary.Whether the department believes in the state-ments and conclusions drawn by an author or not,it always respects straight thinking, and that isprecisely what this book lacks. There's no think-ing in it, at all; it's simply a collection of blindspleen.

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threw the book into the waste -basket and went intothe park across the street to let the sunshineand this same nature that Lewis deplores so,keep him from doing murder.

THE EARNING POWER OF RAIL-ROADS. By Floyd W. Mundy. Leather.442 pages. Jas. H. Oliphant and Co., NewYork.This little book of statistics and notes deals

with the financial engineering side of the railroadproblem. In the financial statements, set out



at the opening of the book, is given the totalcapitalization, bonded indebtedness, and the yearlyearnings, gross and net, of the roads of the UnitedStates and Canada. In the notes following thetext, there is a large fund of information as tothe present organizations, changes that have takenplace during the last year, and comments on thegeneral financial condition of the roads.

This volume is the seventeenth annual edition.

BY WIRELESS FROM VENUS, or THEPRIMAL ELEMENTS. By CharlesHenry Taylor. Board, 391 pages. ThePlanet Book Distributers, Los Angeles,Calif.It is all settled, this question of Spiritualism.

"By Wireless from Venus" settles it. In the in-troduction, the author states that the book iswritten in fictional form so it can more easilyreach the minds of the readers. Why take it asfiction? It settles everything.

The author divides all life into two forces,namely electricity and viticity. The first is wellknown, the second is the author's great contribu-tion to science. It's the vibration of life, he says,and the motive power of all life. All materialthings are electricity, all animate things are mo-tivated by viticity, the author's discoveries.Simple, isn't it? He says the alleged phenomenaof spiritualism, the work of mediums, spiritwritings, and all such, are not miracles at all;says there is nothing mysterious about them,that they are simply the natural workings of theviticity.

But he not only settles the problems of themind but also the problems of astronomy. Theuniverse, we are told by him, is built around onecentral star about which all the suns revolve intheir orbits and around which, in turn all theplanets and their satellites revolve. Quite simple,the universe.

INSECTICIDES AND FUNGICIDES;SPRAYING AND DUSTING EQUIP-MENT. A Laboratory Manual with Sup-plementary Text Material. By 0. G. An-derson, Professor of Horticulture, PurdueUniversty and F. C. Roth, Instructor inHorticulture. Purdue University. Cloth,337 pages, illustrated.This manual offers instruction in preparing in-

secticides and fungicides as applied to horticul-tural crops. A detailed study of spraying anddusting equipment is also included, and this sub-ject is treated from the standpoint of those whomust use these appliances. Aside from its valueas a general reference, that portion of the bookwhich deals with appliances, and their efficient op-eration, will be of special interest to park superintendents, nurserymen, and county agents. A newtreatment of the subject is also offered to thoseengaged in the manufacture and distribution ofspray and dust materials and machinery.

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HANDBOOK OF CHEMISTRY ANDPHYSICS. By Charles D. Hodgman,M. S., and Norbert A. Lange Ph.D.,size 63"x4'4". Flexible cloth covers,803 pages. Published by ChemicalRubber Publishing Co., Cleveland,Ohio.This book, now in its ninth edition, has been com-

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Light is also dealt with in a very comprehensivemanner and under the chapter on MiscellaneousTables are found such things as R8ntgen Rays,Meteorological Data, Acceleration of FallingBodies, etc. Two chapters are devoted to Form-ulas, one to Laboratory Receipts and the otherto Photographic Formulae.

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THE FACE OF THE EARTH ASSEEN FROM THE AIR. By WillisT. Lee. Illustrated, 110 pages. Hardcloth covers, size 10"x7". Published byAmerican Geographical Society, NewYork City.Within the covers of this book is found oneof the most complete collections of aerial photo-graphs ever gathered together in one volume. The

book is printed on coated stock which lends itselfvery well to the reproduction of the various photo-graphs. The pictures are by far the outstandingfeature of the work and as an introduction, thefirst photograph in the book is one of the NationalCapitol, at Washington, D. C., taken from theair. The details in the photographs are marvel-ous and the methods of taking the various onesused for illustrations are thoroughly covered.Composite photographs are also dealt with and therelationship between landscape -gardening andaerial photography is well put forth. A furtherchapter deals with the making of maps from aerialphotographs and the value of such pictures iswell put forth. Maps of portions of mud flats in-accessable to surveyors are shown.

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PROBLEMS OF MODERN SCIENCE.Edited by Arthur Dendy, D.Sc. F.R.S.Size 8..>"x5,/2". Hard cloth covers, 236pages. Published by Henry Holt &Co., New York City.In this work the editor has brought together

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PRACTICAL PRINTING PRO-CESSES. By Frank R. Fraprie, S.M.,F.R.P.S. Size 7,/2"x434" Hard clothcovers, 56 pages. Published by Ameri-can Photographic Publishing Company,Boston, Mass.

This book, No. 10 of the Practical Photographyseries, has already run over 18,000 copies and inthis latest edition has been completely revised andenlarged.

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most complicated. The book opens with severalpages on general instructions, cautioning the photo-grapher on the importance of cleanliness in photo-graphic work. Blue prints and printing -out papersare then dealt with and formulas given for themaking of blue print paper and transparencies.This method of presentation is continued through-out the book and it is replete with formulas set-ting forth the methods for preparing various print-ing papers as well as other formulas for the prep-aration of developers and fixing baths. Directionsfor sepia toning processes are also given as aredirections for applying the same to all kinds ofpaper.

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DISCOVERIES AND INVENTIONSOF THE TWENTIETH CENTURY.By Edward Cressey. Illustrated, 453pages. Hard cloth covers. Size 8%"x51A". Published by E. P. Dutton &Co., New York CityThis book dealing with the various inventions

and discoveries of the past twenty-three years isvery well compiled and illustrated. Some of thesubjects touched on are the development of steam,gas and oil for power, the various developments ofgasoline engines, the latest advances in generationand transmission of electricity, improved electriclighting and heating systems, new developments inartificial refrigeration, the latest discoveries inchemistry, the motor car up-to-date, aeronautics,wireless telegraphy and telephony and high speedphotography. The chapter on aeronautics is wellworth special mention as not only the theory oftransportation through the air is dealt with, butphotographs of the various latest types of air-planes and dirigibles are shown. The chapter onwireless telegraphy and telephony is practically thesame as found in the first chapter of any standardradio hand -book, dealing as it does with the earlydays of radio history and touching lightly uponsome of the newer developments.

Taken as a whole, the book is one which shouldinterest any student of general science.

THE BOOK OF WIRELESS TELE-GRAPH & TELEPHONE. By A.Frederick Collins. Illustrated. 227pages. Hard cloth covers. Published byD. Appleton and Company, New York.This book is one which should appeal to every

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THE MEANING OF RELATIVITY.By Albert Einstein. 119 pages. Hardcloth covers, size 71/1"x5". Publishedby Princeton University Press, Prince-ton, N. J.This is a book written as only Professor Al-

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U.S PATENTS

Don't Lose Your RightsBefore disclosing your invention to any-

one vend for blank form "Evidence ofConception" to be signed and witnessed.A sample form together with printed in-structions will show you just how to workup your evidence and establish your rightsbefore filing application for patent. Asregistered patent attorneys we representhundreds of inventors all over the U. S.and Canada in the advancement of inven-tions. Our schedule of fees will be foundreasonable. The form "Evidence of Con-ception" sample, instructions relating toobtaining of patent and schedule of feessent upon request. Ask for them,-a postcard will do.

255 OURAY BLDG.,WASHINGTON, D. C.

"Originators of form Evidence of Conception"

TO THE MAN WITHAN IDEA

I offer a comprehensive, ex-erienced, efficient service foris prompt, legal protection and

the development of his proposi-tion.

Send sketch, or model and descrip-tion, for advice as to cost, searchthrough prior United States patents,etc. Preliminary advice gladly fur-nished without charge.

My experience and familiarity withvarious arts, frequently enable me toaccurately advise clients as to prob-able patentability before they go toanioeoxpeenseBooklet o.f valuable informationand form for properly disclosingyour idea, free on request. Writetoday.RICHARD B. OWEN, Patent Lawyer164 Owen Building, Washington, D. C.2276-8 Woolworth Bldg., New York City

PATENTSC. L. PARKERFormerly Member Ex-amining Corps, U. H.

Patent Offices.PATENT LAWYER

McGill Bldg., Washington. D. C.Patents,Trade Marks, Copyrights,Patent litigation

Handbook for Inventors. "Protecting. Exploitingand Selling Inventions." sent upon request.

Edited byJoseph 11-N. Kraus

In this Department we publish such matter as is of interest to inventors and particularly to those whoare in doubt as to certain Patent Phases. Regular inquiries addressed to "Patent Advice" cannot be answeredby mail free of charge. Such inquiries are published here for the benefit of all readers. If the idea isthought to be of importance, we make it a rule not to divulge all details, in order to protect the inventoras far as it is possible to do so.Should advice be desired by mail a nominal charge of $1.00 is made for each question. Sketches anddescriptions must be clear and explicit. Only one side of sheet should be written on.

NOTE:-Before mailing your letter to this department, see to it that your name and address are upon theletter and envelope as well. Many letters are returned to us because either the name of the inquirer or pisaddress is incorrectly given.

TURN INDICATOR(759) A. Levine, Los Angeles, Cal., requests

our opinion of an automobile right and left turnindicator made as shown.

A. We do not advise applying for a patentupon your automobile extension light, for indicat-ing right and left turns, for the simple reasonthat such extension arms have not met with verygreat favor. Here in New York signaling devices ofthis nature, entirely automatic, and operating fromthe clutch for the stop signal, and from the wheelfor the right and left turn, are being sold verycheaply. Indicators of the nature you describehave not met with very favorable markets. At-tempting to place this device upon the market is agambling venture which we do not advise you toundertake.

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"1.

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Some auto turn indicators similar to the above are manu-factured at present and haven't found a healthy market.

DOUBLE PHONOGRAPH RECORD(760) Samuel H. Landis, Lane, Pa., asks why

phonographic records are not made so that onesong can be played with a hill and dale producerand another with a lateral cut producer, both onthe same face of the same record.

A. We can answer your question very simply.Take a hill and dale record, place it upon yourphonograph, and set your needle to play laterallycut records. You will find that, regardless of whatyo:i do, you will get a sound. Reverse the process,and use laterally cut record with a hill and dalereproducer, and again you will reproduce music

INVENTORS PROTECTYOUR IDEAS

Write for our Guide Book, HOW TO GET A PATENT, and Evidenceention Blank, sent. Free on request. Tells our terms, methods, etc.

model or sketch and description of g.your invention and we will give ouropinion as to its. patentable nature.

RANDOLPH & CO.Dept. 172, WASHINGTON, D. C.

Name

of In -Send

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with a great many distortions and scratching noises.Consequently, your device, although of interest,could not very well be perfected, because of thefact that both records would be heard simultan-eously, one a little weaker than the other.

Tie -pins with removable heads like the above could hardlybe sold "by the millions" as the inventor asserts.

REMOVABLE TIE PIN STONES(761) William King, Wonessen, Pa., asks us

what we think of the idea of making tie pins sothat the stones or fronts can be removed.

A. We have recently advised four individualsagainst trying to patent either removable stones fortie pins, or removable tie pin fronts. We do notagree with you when you state that the pins couldbe sold by the millions.

HIGH POWER LIGNTREFLECTOR

Ht11"1":2

RECTIFIED war

WHITE LIGHTOr-

RAYS...

T

lerOBJECTILLUMINATED

OBJECTILLUMINATED

For portraying articles in their day -light colors the abovedevice is good if it will work, actually.

NATURAL LIGHT REFLECTOR(762) Don Lowery, Moundsville. Fla., asks

whether a lamp for interior decorating made asshown, would give objects their true lustre.

A. We do not believe that the reflector whichyou have designed will have any effect whatever,and it is our opinion that instead of giving objectstheir true lustre, the reflector will throw a seriesof concentric colored bands upon the object towardwhich it is turned.

The experiment is nevertheless, not too costlyto try and we would suggest that you build amodel before proceeding further. An absolutelyperfect parabolic reflector and pure white lightarc necessary in this test.




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ATREGISTER ED IN UNITED STATES PATENT OFFICE

MEMBER OF THE BAR OFSUPREME COURT OF UNITED STATES, COURT OF APPEALS DISTRICT OF COLUMBIA,SUPREME COURT DISTRICT OF COLUMBIA. UNITED STATES COURT OF CLAIMS.

PRACTICE CONFINED TO PATENTS AND TRADE MARKS,

PROTECT YOUR IDEASANY NEW article, machine, design or improvement thereof, or any new combination of partsor improvements in any known article which increases its efficiency or usefulness, may bePatented, if it involves invention.

Drafting and Specification Room of Clarence A. O'Brien, Registered Patent Attorney, Washington, D. C.

IF YOU HAVE ANY NEW IDEASwhich you feel are useful, practical and novel, takeprompt action to protect your rights. If you haveinvented any new machine, or new combination ofparts of improvement, or any new design or process,SEND DRAWING, MODEL OR DESCRIPTION ofit for information as to procedure to secure protection.

Write Today for Blank Form"Record of Invention"

USE THE COUPON attached, and immediately uponits receipt I shall send you this form to be returnedto. me with drawing, description or model of youridea; promptly upon receiving your idea I shall writeyou fully as to procedure and costs.

No Charge for This InformationAll communications are held in strict confidence. Mypersonal, careful and thorough attention is given toeach case. I offer you efficient, reliable and promptservice-based upon practical experience. Highestreferences.WRITE TODAY for free book "How to Obtain aPatent."' This book will give you valuable informa-tion, and it may save you much time and effort. Sendfor it, NOW.My practice is devoted exclusively to United Statesand Foreign Patents and Trade Marks. Write mefreely, frankly and with full confidence; it is veryprobable that I can help you. Write TODAY.

CLARENCE A. O'BRIEN, Patent Attorney, 53A Security Savings & Coml Bank Bldg.Directly across street from Patent Office, Washington, D. C.

Please send me your free booklet "How to Obtain a Patent" and blank form "Record of Inven-tion" without any obligation on my part.

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Pateult Advice(Continued from page 922)

';11111111IL

INDIVIDUAL CRACKER CRUSHER(763) John Lisinski, Mt. Carmel, Pa., asks our

-minion of an individual cracker crusher for res-taurants.

A. Modern restaurants have regular crackercrushers. Some of the smaller restaurants areusing a small ringer for this purpose. In neithercase are these cracker crushers put to any greatuse because crushed crackers are not being servedin restaurants, it being considered more refinedto serve the whole cracker, and except in cakesor stuffings, the crushed material is not of value.If crushed crackers are desired, restaurants canpurchase them in cartons all ready in a crushedand sifted form, so that all the granules are uni-form in size.

We would not suggest applying for patent onthe invention here described.

Since whole crackers are served in restaurants and sincevery few people crush them when eating, the above idea is

hardly valuable.

VACUUM WINDOW GLASS(764) S. A. Lind, Alameda, Cal., asks us for

our opinion on a window glass made of two panessealed at the edges and the air exhausted.

A. Our opinion of a double sheet pane of glasswith a vacuum between the individual sheets isvery poor indeed.

In the first place such glass could not be cutand made to fit varicus sized window frames.Consequently, an immense amount of glass wouldhave to be kept in stock.

In the second place, this glass is liable tobreakage to a greater extent than ordinary windowglass, due to the fact that the point at whichthe glass is exhausted must be much thinner thanother portions of the glass. Furthermore, glass ofthis nature cannot be tr.r.de to fit ordinary frames,because of the exhausting projection; the sheetsof glass, unless very thin indeed, would have dif-ferent amounts of expansion, due to the fact thatcne side is being heated while the other is keptcool. Last but not least, the expense of manufac-ture is prohibitive. Atmospheric pressure wouldtend to break the panes.

The idea is, as stated before, not practical, andwe would not advise applying for a patent.

AIR EVACUATED HERE

VACUUMA window pane made of two glass sheets sealed and the

air exhausted is not practical for a number of reasons.

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A THEORY BASED ON MISTAKENIMPRESSIONS

(765) M. Knickerbocker, Mokena, Ill., hasevolved a theory in which radio waves are to hefocussed to one spot. He assimilates radio wavesto light waves and sound waves and asserts thatwireless waves are reflected by a convex mirror.

A. Radio waves transmitted through the ethercannot be focussed the same as light or heatwaves. The waves pass through glass veryreadily. The vibrations differ from sound inwave -length, medium of transmission and speedof travel. Sound waves travel at a rate ofroughly 1,190 ft. per second through the air, withan additonal speed of 2 ft. more per second forevery degree rise in temperature of the surround-ing atmosphere over zero C. Electricity on theother hand, travels at 186,500 miles per second.Temperature has no effect upon its speed oftravel; at least normal temperature variations donot effect it. The ether is the medium of itstransmission.

Sound travels better in denser mediums, travel-ing 1,315 ft. per second in water at 0° C, whereasradio does not change its speed, as it always hasthe same medium of transmission.

CLOTHES HANGER AND REMOVABLESTONES FOR TIE PINS

(766) William E. King, Monesseu, Pa., asksfor advice on two ideas. The first is a hanger forgarments; the second is a suggestion for removablestones for tie pins.

A. In our opinion, the suggestions advanced byyou are about half good. Coat hangers such asyou have designed, may without a doubt, be veryeasily constructed, but the grip arrangement whichyou intend to use for holding light clothes, is avery undesirable feature. A slight tug at the flimsygarment, if held on one of these coat hangers,would tear it, thus destroying the garment's furtherusefulness. A far better suggestion would be toemploy a rubber pad, fitted with a steel spring,under which the garment could be held. Needlessto say, the garment hangers of your particular de-sign and construction, are rather expensive, eventhough you have worked out the manufacturingdetails to a very great extent.

Less favorable is your idea of inter -changeabletie pins. It is much easier to retain a tie pin whichis a complete unit, than it is to hold on to aseparable device. The cost of the shank alone inthese tie pins is practically negligible, and it isthe stone or the finer design or figure which is themost valuable part of pins. Therefore, your inter-changeable mechanism, will not reduce the cost ofthe tie pins to a very great extent, and the un-desirable feature is that each change has to con-form general tie pin shape. Open-work tie pins could not be employed or attached toyour device.

You see, therefore, that we do not have verymuch faith in either of your two ideas, and wouldbe skeptical toward advising you to apply for apatent on either.

CLOCK -WORK OPERATED MECHANISM(767) Everett A. Manning, Decatur, Ill., asks

if he can patent a device depending on a clockmechanism for its operation.

A. Of course, a device using the works of analarm clock for its functioning, and dependingsolely upon the running of the clock for its opera-tion could be patented if otherwise conforming tostatute.

If it depends upon one particular style of clock,then it is an entirely different matter, but inasmuchas nearly all clocks run and most are equippedwith alarms, and inasmuch as the patents on clocksor clock mechanisms are so old that they havelong become public property, we see absolutely noreason for your not placing your device upon themarket, if it is worth while.

IGNITION CUT-OFF(768) L. L. Meyer, Lead, So. Dakota, has de-

signed a thermostatically controlled device for auto-mobiles which will cut off the ignition as soon asthe temperature of the water of the cooling systemreaches a predetermined point.

A. In your communication, requesting patentadvice, you have given a design of rather ingeniousprinciple, but upon which we cannot favorablycomment. There are many reasons for this, a fewof which may suffice.

It would be very undesirable, for instance, toinstall one of these systems upon a car, and afterdriving in low gear, as through country towns, soas to heat up the motor considerably, and afterfinally reaching a ferry pier or railroad crossing, oran intersection in a busy street, to have this auto-matic device turn off the ignition and stop the cardead. It may be that the driver had attempted tocross the railroad tracks before the gates werelowered, and an approaching train was bearingdown upon him, enabling him to cross the trackordinarily in safety, but because the ignition wentdead, to stall, and perhaps send the car's occu-pants into the region of the Great Beyond. Thisis not a very satisfactory outlook, we can assureyou. If your device is merely to sound an alarm,then it will have no value either. The system isfar more expensive than the motometer, both toinstall and to operate, the latter requiring noenergy of any sort, while your system consumescurrent constantly.

In our opinion such a system would never finda favorable market.

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IV

OUR OFFER ation and InstructionsNo Charge for Examin-

YOUR FIRST STEPBefore disclosing an invention the inventor should write forour blank form "Record of Invention". This should besigned and witnessed and returned to us together withmodel or sketch and description of the invention for ex-

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PERPETUAL MOTION(769) Joseph McDonal, Providence, R. I., asks

to whom he could apply for bona -fide advice onperpetual motion.

A. You may feel free to discuss your perpetualmotion plan with us, and we will give you the bestadvice possible. We do not hold the inventor ofa perpetual motion machine up to ridicule andscorn, and neither do we deride an inventor for hisopinion. We try to explain the matter as clearlyas possible, although at times we find it ratherdifficult to convince perpetual motion inventorsthat the machine they have designed is impossibleof operation.

If you will make your sketch clear, and give usyour own reasoning on the subject, we will at-tempt to point out your error, if such exists.

PATENT ATTORNEY VS. INVENTOR(770) R. J. Mark, Lincoln, Neb., asks if a

questionnaire which he has received from a patentattorney, should be filled out and if the attorney in-tends to steal the idea if it should be filled out.

A. We do not believe the patent firm meansanything in sending you the questionnaire. Allquestionnaires of this nature are required by cer-tain firms to be executed merely for convenience,not because of any attempt to steal the idea. Themain point at issue is that they desire to determinewhether or not you have fully protected yourself,so we would advise you to make a truthfulreply to the questions, and if the device originatedfourteen or eighteen years ago, state so. Be sure,however, that you claim the day of the making ofthe first sketch, etc., and also the date when themodel was built.

HOTEL LOCK AND TIE PINS(771) A. I.ippert, Toronto, Canada, asks us

for advice on a duplex lock for hotels which can beopened from the outside even though the key isin the lock, and if he should patent two safety tiepin shanks.

A. We do not believe that your idea of a hotellock will have any value for the simple reason thatif the hotel lock can be opened from the outside,regardless of whether patron's key is in the lockor not, thieves with pass -keys could easily openthe lock. If electric circuits were placed upon thelock so that any attempt to tamper with it whilethere is a patron sleeping inside the room wouldalarm the sleeper, then those circuits, or the bellcould be destroyed. Besides there are about four-teen different attachments made for ten centseach to he slipped between the door jams and thedoor, which permit the placing of a small catchacross the back of the door, securely locking thedoor and preventing intrusion. Consequently, yourdual lock would be worthless.

With reference to your wavy pins, and your otherstick pins, we would state that the former style isnot new at all, having been in use a great manyyears. It is now practically obsolete. The pinwith the small V may be of some value, but wedoubt very much if it will meet with any degreeof favor, in that the structure of the pin is suchas to tear ties in an attempt to extract the pin.It would require considerable fussing to loosen agood quality silk tie from the pin, and even morefussing if the user were wearing a heavy crochetedneck tie.

ROTARY GAS ENGINE.(772) A. H. Phillips, Hulberton, N. Y., sub-

mitted a model of a rotary gas engine, the de-tails of which are omitted for the protection ofthe inventor. The blades of the turbine revolveand form their own explosion chambers, butthe manner in which they did so, was very unique.

A. Of the thousands of patent advice inquirieswhich we receive, regarding rotary gasoline mo-tors, the one submitted by you is better than anywhich have thus far been called to our attention.

We do not doubt that if this patent is properlyhandled, a very clever motor would be developed,which is bound to "take" but it will require con-siderable money to do this. We would suggestthat you have a full-size model built after you havesecured the proper patents. There are severaldetails which will have to be worked out, namely,the method of making the vents tight and thecontrol of the gears. Your descriptions are ex-tremely clear, and for the crude model you havedesigned and built, its working principles areclearly explained. We wish you the best of suc-cess in your venture.

STATIC ELIMINATOR(773) Leonard Peulter, Fort William, Ont.,

Canada, has designed a static eliminator for radiosets made in the form of ebonite and wax rods.He states that these substances conduct static elec-tricity and are used as insulators in radio sets.He then illustrates his theory by a physical ex-periment.

A. The static eliminator which you have de-vised may suggest a possibility to you, but is acomplete absurdity to any one who knows whatstatic electricity is. Static electricity is notconducted by hard rubber, bakelite. glass or resin.It is, nevertheless, charged upon the surfaces ofthese materials when they are rubbed with propersubstances, and metal is used to lead the chargeoff. Consequently, metal combs and brushes areused in static machines to collect electricityformed on the plates.

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Book Review(Continued from page 921)

said many times, that there are only twelve menin this world that understand relativity, here iseach one's chance to learn of this subject if theyare willing to go through the deep calculuscomputations given in this book. A completeindex gives ready references to the various cal-culations and other rules set forth in the book.

LABORATORY MANUAL OF PHY-SICAL CHEMISTRY.. By Davisonand Van Klooster. 182 pages, hardcloth covers, size 91/4"x6". Publishedby John Wiley & Sons, New YorkCity.This book is one which is used in the physical

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The last few pages of the book are devotedto tables which will be of constant use to the

performer of the experiments outlined in thevolume, and following these tables will be foundblank pages of graph paper for the constructionof curves plotted from the experiments performed.For easy reference, each experiment is listed

with its page number in the table of contents.In order that the experimenter may have full

information on the work, a list of referencebooks is given from which he can obtain furtherinformation on the work at hand.

RADIO -PHONE RECEIVING. ByErich Hausmann, Sc.D., Alfred N.

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This book, written by nine experts in the radiofield is a clear and concise explanation of thephenomena and theory of radio. Each experthas written on a subject for which he is mostnoted and, therefore, the cream of radio knowl-edge is presented to the reader. The tuning ofthe radio receiving circuit is very clearly ex-plained as is clso the theory and practice of re-ception with the use of crystal detectors.

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(Continued front page 916)GOWUUMWMMUMUUWMWMP.11 lllll MUMWUMWUW.AUUMUMIMUW11111111m.M.Imiall,w

Aside from foot rests, one of the most important thingsto the worker who is forced to sit 'n one place in more orless the same position for a whole day at a time, is a backsupport of some kind. Where the e is no back rest andthe feet are forced to hang without touching the floor morefatigue may result from sitting all day than from stand-ing. Aside from the tiring effect of the position it has atendency to form a curvature in the body that causescramping of the upper organs on the diaphragm and the

digestive tract.

One of the most advisable arrangements that can be madefor the health of the workers is to arrange the benchesor work tables so that they may be used either in thesitting or the standing position. Above is shown such a deskfitted to the proper height and supplied with the properfoot rest. The stool, it will be noticed, also has a con-venient back rest. This is the best design for certainoffice and laboratory or shop furniture. It will cause the

minimum of fatigue.

When workers are forced to sit in cramped positions it isbest to change the nature of their work at short intervalsand to change it in such a way that each succeeding posi-tion will tend to rectify the effects of the previous one.For instance, if the worker is required to lean forward onone piece of work, it should be arranged so that she maystand more or less straight at the next one. Also there

should be frequent rest periods in the day's routine.


YOU TOO CAN PLAY THE

HAWAIIAN GUITARJUST AS THE HAWAIIANS DO!

PLAY ALL THE LATEST HITSAfter Your FIRST LESSONWill Play a Complete Selec-tion. We Guarantee That --Our method is eo simple, interestingand appealing that you begin in yourfirst lesson to learn the famous Ha-waiian FolkSong"ALOHA".Thinkhow happy you will be when yousurprise your friends by playingthe fascinating Hawaiian Guitar.

Only Four Motions --and You Master Them Quickly!'Ina few minutes you acquire the four motions Decease...3, to play anstt

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.beauttrul HawaiianGuitar, necessarypicks, steel rar, etc. No entree.No Previous Musical Knowledge Necessary

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ff our remarkable FREE Hawaiian Guitar Of-er -simply write: 'I am Interested" -but do it today.First Hawaiian Conservatory

eye tat eaaraea of Music, Inc.Violin,TrnDe, 19 -23:0-v.va

jo. Banjo__Scua NDesk.- 131,1g.)

and Ukulele. New York City

A BeautifulHawaiianGuitar

VACCU-PUMPSNeeded by reel y Doctor. Dentist,Chemist, Mechanic, garage repairshop, radio experimenter, college andlaboratory.

Many UsesWill exhaust vacuum tubes, start a syphon,empty auto gas tanks by suction, drawliquid from inaccessible places, transferacids, and supply a vacuum for any med-ical or laboratory use. Price with gauge,hose, and bottle, $10.00. Without gauge.$6.00. Circulars on request.

A. B. C. LABORATORIES CO.100 Lawrence St., N. Y.

West 120th St.

Develop Your Ideas At HomeWith a

Boice JuniorBench Saw

Do your ripping, mit-ering, grooving, rab-bettin g. tenoning,sanding, grinding, andmany other operationswith surprising ease and accuracy.Top 10"x13". Saws 1%" stock. Dadoes 55"s%". Machinebuilt entirely of metal. Driven by '4 or 1/3 hp. motor.Portable. Attaches to any light socket. Extremely accurate.Write for descriptive literature on Bolce-Built Bench Saws.lathes, drills, jointers, band saws, and motors.

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E BXEP E %REPAIRMANOn MOTORS and GENERATORSRepair and Maintenance Men Are in Big

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SCHOOL of ENGINEERING of MILWAUKEESAL -124A 415-17 Marshall St., Milwaukee, Wis.

LATHES9 to 18 -inch SwingList price 9135.00 and up,according to size. Whenready to buy, send forLathe Catalog and prises.

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The Tone and Quality Long Looked ForUsed by Hoiletz, Kreisler, easels and all other great artistsThis Modern Scientific Con-struction has improved thealmost perfect instrumentssincetheirCreation.Try itand compare. If not satis-factory money refunded.

Free Catalog of 1923-1924 on request.J. & 1. VIRZI BROS., 503 Fifth Avenue, New York City



.111WIIIITITIMIIIIMTIIIIIII1M111111111111111111111.1111111,10/11:1111m11111111111,11111111111iHm117111,7111111M1111"4

Airhsvversto ScienaficFuzzIles

(Continued from page 880)101111111111114.11110111111111111111111.111111111M1111111111111111111111111111111111111111111.111111111111111111.1111111111

THE DRUGGIST'S BALANCEANUMERICAL example will perhaps

illustrate most clearly the effect of in-equality in length of the arms of a

beam or platform balance. Suppose for sim-plicity that one arm is 12 inches long and theother only 6 and that the druggist wants toweigh out 10 oz. of material. If he places aten ounce weight on the long arm of thebalance he will have to counter -balance itwith 20 oz. of material which he will sell forthe price of 10 oz. But if he places theweight on the short arm he will have to bal-ance it with only 5 oz. of material whichagain he will sell for the price of 10 oz. Onthe average, then, he will dispense 25 oz. ofmaterial at the price of 20 oz. which meansa constant loss on account of the imperfectionin the balance.

A QUESTION OF ELASTICITYIn general a glass ball will bound much

better than a rubber ball provided of coursethat the former does not chip or break in theprocess. This is because glass, contrary tocommon opinion, is far more elastic thanrubber. By elasticity, it should be remem-bered, we do not mean stretchableness, forin that sense taffy would be very elastic in-deed. To be elastic a body must have a tend-ency to recover its original shape quicklyafter being distorted, in which sense glass issurprisingly elastic notwithstanding its greatbrittleness which sometimes gives us a con-trary impression.

THE PROBLEM OF THE SWIMMERSLet V be the speed of swimmers in still

water,V1 the speed of the stream,

and D the distance to the turning point.Then the speed of the swimmer going

downstream is V + Vi and his speed up-stream V - V1. The time required to makethe complete trip downstream and back will

D Dbe t1= V+ + V - V2 -

DV -- DV, -I- DV + DV, 2 DVV' - V12 V'- V,'

The other swimmer, who swims across thestream, makes the same speed both ways, buthis net speed is not equal to that in stillwater, for he must constantly swim up-stream a little to avoid being carried downby the current. Adopting the notation usedabove, the speed of the swimmer goingacross the current will be V2 = V V' -and the time required to make the complete

2Dtrip will be t2 - V V' -On dividing the expression for ti by the ex-pression for t2 we see that

2 DVV' - V,' V

2D V V'- N/12V V' -From an inspection of this last equation it isapparent that the denominator of the righthand number is less than the numerator forany positive value of V1, the velocity of thestream. Hence t2 is less than t, which indi-cates that the swimmer going across thestream should win the race.

WEIGHING THE COALThe answer to this problem depends upon

whether the platform of the scales was abovethe level of the ground, on the level of theground, or below the level of the groundwhen two of the wheels of the wagon were

Giving the Telephone LifeWherever your thought goes your voice may go.

You can talk across the continent as if face to face.Your telephone is the latch to open for you anydoor in the land.

There is the web of wires. The many switch-boards. The maze of apparatus. The millions oftelephones. All are parts of a country -widemechanism for far -speaking. The equipment hascost over 2 billion dollars, but more than equipmentis needed.

There must be the guardians of the wires tokeep them vital with speech -carrying electricalcurrents. There must be those who watch themyriads of tiny switchboard lights and answeryour commands. There must be technicians ofevery sort to construct, repair and operate.

A quarter of a million men and women areunited to give nation-wide telephone service. Withtheir brains and hands they make the Bell Systemlive.

"BELL,,SYSTEM"AMERICAN TELEPHONE AND TELEGRAPH COMPANY

AND ASSOCIATED COMPANIES.One Policy, One System, Universal Serviceand all directed toward Better Service

WHY SPEND MONEYTO GO TO A TRADE SCHOOL?

Train with a real company that will use you when your training is finished.Here's a company that will train you; put you in one of their shops forpractical experience and go into business with you after you finish.Some day we are going to control the Automobile Electrical Service gameand are training men for our own use.Will you be with us? For information write to

MOTOR CAR IGNITION CO., Inc. 5036C-R.ENT2A5LthDsIty,IgilcOeNro,,Dehpitc.a2g006,

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EARLE E. LIEDERMAN as ho is today

Start the New Year RightWill 1924 Bring

SUCCESS or FAILURE?Right now is the time to decide. I f you

had started right one year ago you would beon the high road to success this very minute.Dont let another year pass you by. It is with-in your power to make yourself just what youwill. Make this day the beginning of a newlife and a better one.

I WILL GIVE YOU WEALTH,HEALTH AND HAPPINESS

I will transform that body of yours andPhysically perfect. I will make a real HE man outof you. I will build out your chest so that everybreath means increased life, purifying your bloodand sending vim and vitality throughout your entiresystem. I will broaden your shoulders and give youtire huge muscular arms and legs of an athlete. Iwill put pep in your old backbone and strengthenevery vital organ within you. You will be just bub-bling over with life, having the keen, alert brain,the bright flashing eyes and the spring and step ofyouth. You will be admired and sought after in boththe social and business world. You will be a leader ofmen, and the good things of life will naturally comeyour way.

I CHALLENGE THE WORLDIf a man stood on the house -tops and shouted to

the people that he was the strongest man on earth,it would avail him nothing. Someone would makehim come down and prove it. But records speak forthemselves. I will gladly show anyone personalletters from the leading strong men in the worldtoday that my course is absolutely the best and thequickest to acquire physical perfection. Come onthen and make me prove it-I like it. I have themeans of making you a perfect physical specimen ofmanhood, of making you a successful leader of men.You will be a credit to your community. I have donethis for thousands of others. What I have done forthem I will do for you. I don't care what your pres-ent condition is. The weaker you are, the morenoticeable the results. Come on then, start theNew Year right.

Send for My New 64 -Page Book

MUSCULAR DEVELOPMENTIT IS FREE

It contains forty-three full -page photographs of my-self and some of the many prize-winning pupils Ihave trained. Some of these came to toe as pitifulweaklings, imploring me to help them. Look themover now and -you will marvel at their present physi-ques. This book will prove an impetus and a realinspiration to you. It will thrill you through andthrough. All I ask is 10 cents to cover the costof wrapping and mailing and it is yours to keep.This will not obligate you at all, but for the sake ofyour future health and happiness, do not put it off.Send today-right now, before you turn this page.

EARLE E. LIEDERMANDept. 201, 305 Broadway, New York

EARLE E. L1EDERMAN,Dept 201. 305 Broadway, New York City.Dear Sir: I enclose herewith. 10 cents. for which

too -are to- send me, without any obligation on Invpart whatever, a copy -of your latest, book, "MuscularDevelopment." (Please write ut print plainly. )

Name

Street

City State

on the platform. The man's method ofweighing would be all right provided theplatform were even with the ground whenthe weighing was being done, otherwise apreponderance of the weight of the wagonand load would be thrown either upon thescales or upon the ground, in one case mak-ing the apparent weight too great and in theother too low.A FEW EXPERIMENTS IN AN ELEVATOR

(a) According to the theory of relativitya person moving with a constant velocity ina straight line cannot possibly detect his mo-tion without performing an experiment onsome other system. For example, though thesolar system is in motion toward a certainstar in the constellation of Hercules not onlyare we not in the least conscious of this fact,but no apparent departure from the laws ofmechanics can be noted on account of thismotion. The only knowledge we have of thisvelocity comes from observations of the lightfrom various stars, that is, from an experi-ment on another system. So unless the manin the elevator has some means of getting in-formation from outside his cage, he might hetravelling with a terrific speed without sus-pecting it.

(b) If a man were standing on weighingscales when the cables supporting the eleva-tor broke, the cage would at once fall by theacceleration due to gravitation (32.2 ft. persec.). All objects in the cage would have atendency to fall at the same rate and hencefor the time they would lose all weight. Thesprings of the scales would then recoil andprobably drive the man from the platformto the top of the elevator where he mightremain for the rest of the trip.

(c) If the man in the elevator tried topour out a pitcher of water while the eleva-tor was falling it is evident that the pitcherand water would both fall at the same rateand so no water would flow out. He might,of course, invert the pitcher and then raiseit suddenly, thereby leaving a sheet of waterapparently suspended from the mouth of thereceptacle.

WHY PUT BOILED EGGS IN COLDWATER?

All objects have a tendency to contract onbeing cooled. The contents of an egg, how-ever, will contract more than the shell andhence will pull loose from the latter whenthe hot egg is placed in cold water. This,obviously enough, makes the egg easier topeal.

A CAUTION TO RADIOPHONEFANS

The radio signals which are obtainedIt ith telephone and telegraph line aerials areusually very inferior and great interferenceis often encountered from the currentswhich are carried by these wires. Even con-densers cannot always cut out this inter-ference.

The use of electric light lines is, of course,permissible providing that condensers areused as protective devices because about theonly trouble that can come about through theuse of such a line, even if something goeswrong, is the blowing out of fuses. Thiscauses inconvenience to the amateur himselfand usually to no one else. Several methodsof using condensers for this work were de-scribed in a recent past issue of this mag-azine. However, use discretion in all suchacts and do not rely upon any make -shiftantenna composed of wires which werenever intended to be used for this purpose.Always erect a standard antenna if possible,or, if not, employ an indoor aerial or a loopwith sufficient radio frequency amplificationto build up your signal strength. By sodoing you will avoid all appearances of tam-pering with other persons' property and willget much better results and greater satisfac-tion from your receiving set.

Halfpre-warPrices

Joliet Gibson Club Dance °reheats*

Pleasure and Profit forYou With a GIBSON

You can master a Gibson quickly and soon be playingthe kind of music you like best, alone or in an or-chestra formed among your friends. There are Gibsonorchestras everywhere like the one pictured above, whosemembers have wonderful opportunities for pleasure and

profit. Gibson Orchestras are alwaysin demand.Gibsons are easiest of all string in-struments to learn because of theirscientific construction. Scradivariousarching gives tone of wonderfulsweetness and great carrying power.Guaranteed for life and possessingmany exclusive patented features, yourGibson will be a real "pal" to you.EASY PAYMENTS on any Gib-son instrument, including Mandolin,Mendota, Mando -Cello, Guitar. Harp -Guitar, Mando-Bass, and the new Gib-

son Mastertone Banjo, the supremeinstrument in the field. Send cou-

pon NOW for Free Book andcomplete information; mention in-

strument you prefer. Teacher -Agents Make Big Money; checkcoupon if interested.

INN MI NM =II NM

GIBSON MANDOLIN -GUITAR Co.110 Panora St. Kalamazoo, Mich.

Please send me complete information about

(Instrument)Name

Street or R RP 0

U interested in becoming a teacher -agent check

Genuine German

MAUSERLatest model 9 shot auto-matic. Shoots standardcartridges - lies flat in

cal. $15.65.Hand Ejects!. Revolver, $ 1 0 25

pocket, special at $10.75World's famous Luger DO

swing out cylinder, 32 cal. cal.$14.50: 38 cal.. $15.50. 32 cal. S11,15Brand new latest models. Guaranteed genuine imported.Pay on Delivery SEND NO MONEYPlus Postage

Satisfaction guaranteed or money promptly refunded.Military Trench Auto-matic, 32 cal., 1 shot,extra magazine FREE.Just like you $8.45used over there.,

Glue Steel Army Automatic,25 cal., $7.95: 32 cal., $9.75

Pocket Automatic05 Shoots 7 quick straight

shots (illustrated) regular25 820.00 value, spe-

$6`.05cal. dal sale price....Top Break Revolver, 32 or 38 cal. Special at $8.25.

Watts Trading Co., II Warren St., Desk 65, New York

FREE-This Book on(WOOD FINISHING)

This book, explains how you can easilyand economically refinish and keep fur-niture, woodwork, floors and linoleumin perfect condition. Includes color,harts, cites covering capacities, etc.we will gladly send this hook free andI ostpaid for the name of .your dealer.

S. C. JOHNSON & SON.Dept. S. I. I, Racine, Wis.

"The Wood Finishing Authorities"

en $200,000 equipmentI in great.n shops of Coyne.Complete8 1-2 months. En -

I BirA'ele lAW,71a.°Ti NOWT

eter anytime. Radio course fre-OL

Coyne Electrical School Dept. $3-312300.1310 W. Harrison St.. Chicago. In



OoOOOORTIMMMONPOPIOnallinoonnmorconnoolcmomilioccitoollitOOOMO11111111nococ

A ff0WRINKLES

EDITED BYA. P. PECK,

Associate Member Institute Radio Engrs.

UNDER this heading we are going to pub-lish items of interest to everyone who

likes to build radio instruments. In orderto continue this department it is necessaryfor our readers to tell us about their latestexperiments. Write us a short descrip-tion of some time- or money -saving kinkyou have discovered and send it to us alongwith a few sketches. Our regular prizeswill be paid for this material. Be brief andtry to put everything in the drawing.Don't be too elaborate. Address "RADIOWRINKLES" editor, care of Science andInvention.

Lamp Socket Aerial

FIBER

CASE

BINDING POST --

LEAVE GLASSSTANDARDINTACT

SMALLFIXED

CONDENSER

TO AERIALPOST ONRECEIVING

SET

By constructing a device as shown above and plugging itinto an ordinary electric light socket, a fairly efficientsubstitute antenna will be obtained. The fixed condenserused should have mica as a dielectric. In some cases itwill be found best to connect the shell of the lamp baseto the fixed condenser. This must be determined by ex-

periment.Charles Vivier.

Polarity Indicator

The little instrument indicated above should be kept onhand at all times. By connecting it to a flattery a redspot will be noticed near the negative terminal. By shak-ing the tube, this spot will disappear and the indicator

may be used again.-Harry Cooper.

HowNew Method Makes CartooningAstonishinglyEasy to Learn.

Cartoonists earn from $50 to over $250 a week! Whydon't you make big money in cartooning when newmethod makes it so easy to learn-at home in spare time ?

T HOUSANDS who neverdreamed they could make car-

toons, can now earn big money inthis fascinating field. Right at homein your spare time, you can noweasily learn to make all kinds of car-toons-comic, sport, political, humaninterest and animated. You can nowearn some of the big money paid forcartoons of every description.

And cartooning does pay enormousmoney! Briggs, Bud Fisher, FontaineFox, George McManus, SidSmith and all the other head-liners earn more than thePresident. A single cartoonidea can easily mean a splen-did life -salary for you.

The World's Easiest,Pleasantest and Best

ng ProfessionHow could money be earned

more pleasantly? A f e whours a day at workthat is as enjoyable asplay-and there is al-most no limit to the

C.money that can beearned!

Never before havethe opportunities incartooning been somany or so varied.Never has there beensuch a splendid chance to earn big moneyfor cartoons. And regardless of what youare doing at present or how poorly youdraw now, you can easily and quickly learnto make cartoons through this new easymethod.

New Easy Way to LearnCartooning

It'e fun learning to make cartoons this newway. It's just like a game. You learn at home,yet it is just as if an instructor stood at yourelbow. You don't need to know a thing aboutcartooning. You start with straight lines andcurves. Then you learn the little secrets of orig-inating cartoon ideas, the methods of exaggera-tion, of action and expression-all the littletricks that make cartooning amazingly easy tothose who know them.- And soon you are mak-ing real cartoons. Many of our students havecartoons published before they are half thrutheir courses.

When learning to make cartoons is so easy,why shouldn't you too make big money andenjoy the fun of cartooning? Graduates of thisschool are to be found in every section of thecountry. Read in the panel what they are doingand what they say about this training.

WHATSTUDENTS

SAY:I am now working formyself and find all I cando. I find no trouble incleaning up in thsneighborhood of $250week. I have my ownsyndicate and am grad-ually branching outinto a good field.

R. P.Lawrence, Mass.

Free EmploymentBureau

I want to thank youfor the personal in-terest you haetaken in me whilereceiving instruc-tion from your schooland for referring me to thismagazine.

F. M.-Memphis, Tenn.$125 a Month Spare Time

I wish to take this oppor-tunity to recommend yourschool. I have been doing agreat deal of commercial work-making on the average of$125 a month In spare time.T. W. P.-Charlotte, N. C.

Mail Coupon for Free BookLearn more about the wonderful oppor-

tunities for making money in Cartooningand how this new method makes it easy foryou to learn. Read about our students, howthey make money while learning, and big sal-aries after they graduate. Our handsomelyillustrated booklet is crammed full of interestingfacts on Cartooning and describes in detail thisremarkable method of teaching cartooning. Itwill be sent to you without obligation. Mailthe coupon for this booklet now.

Washington School of CartooningRoom 261, 1113 -15th St. N.W., Washington, D. C.

WASHINGTON SCHOOL OF CARTOONING,Room 261, II 13 -15th St. N. W., Washington. D. C.Please send me, without obligation, your Free Booklet

on Cartooning and full details on your new easy home -study method of teaching Cartooning.

(Please Write Plainly.)

Name(State whether Mr., Miss or Mts.)

Address

City State(If under 16, please give age

Big 3 -Ft. Telescope Utelisi and Entertaining(in Five Sections)

See people and objects miles away, on land or sea, as if they were close. WonderTelescope gives new pleasures to home, farm, camp, travel, sport. See moon andstars as never before. Opens out over 3 feet long; measures 12 inches closed.Brass bound; has powerful lenses. Thousands pleased-"Could tell color ofaeroplane 4 miles away."-Mrs. Yarbrough. "Saw Provincetown Light,28 miles away, as clear as if in front of me."-Clyde Scribner.

SENDNoMONEY''l have bee watching submarines 9 milescif the coaat.n "-P. Grush. "Can seechildren playing in school yard 6miles away.' '-g.HHenning-ton. "Read the numbers onfreight cars mile away.sea mountains opPalmer.As 0.

SRill the fear of stammering. Re-educatIon thekey. The widely famed Hatfield Method fullyoutlined In an accurate, dependOble, worth.while book-"HOW TO STOP STAMMERING." Ahas inspired thousands. Free copy today.

THE HATFIELD INSTITUTE, 109 N. Dearborn, Chicago, Ill.

Because of a fortunate purchase horn a large Europeanmanufacturer we can give you a big bargain. Be first in your

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deposit with Postman only $1.85 plus a few pennies postage. Satisfactionguaranteed or money refunded. Order today while the supply lasts.

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TAMMERNO

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575t,5200a week as an

electrical expertYou can do it! Electricity is the biggest, fastest grow-ing industry in the world today. Hundreds of mil-lions of dollars being spent in development yearly!Mil lions of dollars to be paid for TRAINED BRAINS.A big, high -pay job waiting for you just the minuteyou are ready. Earnings of $15 to $35 and up perday by trained electrical experts are common.

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You start on practical work with our big FREEworking outfit of electrical appliances, so you arenot delayed in getting into actual money -getting work.Associated Electrical Engineers Training includesthe complete courses in RADIO and AUTOMO-BILE ELECTRICITY-the best to be had anywhere-given under the direction of SPECIAL-ISTS, who show you how to make big money.

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Mail the Coupon NOWAssociated Electrical Engineers

OF AMERICADept. C-3 S37 S. Dearborn Street, Chicago

ASSOCIATED ELECTRICALENGINEERS of AMERICADept. C.3 537 So. Dearborn St., Chicago, Ill.Without any obligation, please send me FREE, your 64 -pagebook on Electricity and full details of how I can make bigmoney as a member of the Associated Electrical Engineers.

Name

Address

lesistalceelements

Freeends

Vermeer elementOfigroave"--

!esistance--elements

Pheosiat_.contact

Coarseevement-

Vernier Rheostat

Insadting form for vernier ogre

Sina/e wirevernier

element

/terse -shoe shgoeosector for rheostat

IF EI

IIIWashers

Pamet

Verniercontact armfar fineadjustment

MOM

Shafts10Fil

for coarseadjustment

I the control of a soft detector tube, a vernier rheas atc pable of very close adjustment is an absolute necessi y,particularly for DX work. A combination vernier ands andard rheostat can readily be made following the dir c -Cons shown above. Two forms are used, one in a hor e-s De shape on which is wound the standard rheostat wireto the desired resistance. On the edge of another fo mo the shape shown, is placed the vernier wire. The horse-shoe shaped form is superimposed on the vernier form asillustrated and the connections made as shown.

T. Reglade.

Efficient Grid Leak

Compositionbinding post

t knob

\, Pointer

NutWasher

-StopGraphite fromlead pencil

Solder

Binding Post

The above illustrated variable grid leak is patterned some-what after one of the manufactured type, but it has theadded advantage of making its own resistance path whenvaried. The contacts consist of short pieces of graphite froma lead pencil and the paths are made of the same materialby revolving the arm one or twice. Contact to the bindingposts is made by rubbing a pencil on the panel directlyunder the post and then putting it in place. The resist-ance paths are then connected with the marks which extendunder the binding post and a continuous circuit therebymade. -Carl Webb.

13 wEEK.is,JOR

15 cor4

ePATHFINDER, 555 Langdon Sta., Washington, D. C.

stories. s;e7ds157(cvloil6no:riliirotdi3:5:1"-th°13frgtaper 13weeks. Money bark If not satisfied.); Sample copies free.

You've beard yourneighbor praise the Path-

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half a million subscribers. Unbiased digestof national and world affairs. Chock full of Just the kind of read-ing you want. Fun, fashions, question box, books, health-entertainment and instruction for all. Exciting serial and short

FARN MONETAT HOME

VOU can make $15 to $60 weekly in your sparetime writing show cards. No canvassing

or soliciting. We instruct you by our newsimple Directograph System, supply you withwork and pay you cash each week. Writetoday for full particulars and free booklet.WEST-ANGUS SHOW CARD SERVICE LIMITED

Authorized Capital $1,250,000.0007 Colborne Building, Toronto, Can.

Electrical men with training are in de -mend. For more than a quar-ter of a, century this school has

been training men of ambition and limited time for theelectrical industries. Condensed course in Electrical

Engineering -uatesenables grad -

to se-cure good

positions and promotions. Theoretical and Practical Elec-tricity. Mathematics.SteamaindGas Engines and M echan-heal Drawing. Students construct dynamos, install wiringand test electrical machinery. Course with diplomacomplete In One Year

Free catalog.

3000 men trained. Thoroughlyequipped fireproof dormiterien, dininghall. laboratories, shops.

Free catalog. 31st year begins Sept. 26, 1923BLISS ELECTRICAL SCHOOL

106 TAKOMA AVE., WASHINGTON, D. C.

STUDYAT HOMEJirecte

Int tittibersitp of ebicagoCourses in English. History, Chemistry, Business,Mathematics, Education, Psychology, and 35 othersubjects command credit toward a Bachelor degree.Begin any time. Address 27 Ellis Hall, University ofChicago. Chicago, Ill.

125'By'MAIL

QUESTIONS,..J-41NSWERSElectricians' Examination

Diagrams. symbols, tables.notes and formulas for prep-

aration for license.READE PUB. CO..

296 Broadway. N. Y. CRY

You ::an be quickly cured, if you

STAMMERcured myself after stammering 20 yrs. B. N. Bogue.

Send 10 cents for 288 -page book on Stammering andStuttering, "Its Cause and Cure." It tells how I8100 Bogue Bldg.. 1147 N. III. St., Indianapolis.

restlirtg Book FREETells how to be a great athlete and BoonUbe wrestler-bow to WIN. Startlingsecretstaught In wonderful lessons by world's cham-pions Farmer Burns and Frank Botch. Bestrong. healthy. athletic. Randle big men withease. Learn eelf defen.. Bea leader. Men end

boys, write for Free Book today. State your age.arum Barnach0041251RailwayBhig., Omaha, N

WHY NOT spend Spring, Summerand Fall gathering but -

terfiys, Insects? I buy hundreds of kinds forcollections. Some worth $1 to $7 ea. Simpleoutdoor work with my instructions, pictures,price -list. Send 10c. (not stamps) for my Il-lustrated Prospectus before sending butter -dies. Mr.Sinclair, Dealer in Inseets.Dept.33. Ocean Pk, Calif.

ea FEMALE

WANTED!The Editor requires for his personal use inhis library, the following copies of theELECTRICAL EXPERIMENTERDecember 1915, February, March and April1916. If you have these copies, kindly com-municate with the Editor, stating the valueyou place upon them. Address

Mr. H. GERNSBACK,53 Park Place, New York City



Tapped Honeycomb Coil

For efficient work it is sometimes necessary to have a

tapped inductance coil with a low distributive capacity.This can be made very readily from a honey -comb coil, inthe center of which is mounted any one of the manystandard back -panel mounting switches. If a switch of alarger circumference than the hole in the center of thehoneycomb coil is obtained, a wooden plug may be placedin the hole and the switch mounted thereon. Taps can betaken off from the edge of the coil and connected to theswitch points. The tapping can readily be done by scrap-ing the insulation from a single turn and tinning the ex-posed surface with a light soldering iron. A thin, fairlyflexible wire can then be placed along the tinned portionand soldered thereto. As little solder as possible shouldbe used to avoid short-circuiting other adjacent turns.

-W. W. Johnson.

Honeycomb Coil Variometer

Ilaneyearnb coils

co//S

Dia/ freeto turn

milimrawn( -

Painter

Lott nuts CFour honeycomb coils mounted as shown above and con-nected as a standard variometer as shown at D make avery efficient variometer. Two of the coils are mountedon the base as at A, in which is drilled a hole for theshaft. Two other coils are then fastened to a large dialas at B, and the two units assembled as at C. The shaftis locked to the base as shown, and the dial is free toturn on the other end. The distance between the twosets of honeycomb coils may be regulated by the twolock nuts. -William Williams.

Mounting of Vario-Coupler

Dia/-

Pane'

Bend andotted //he

r214r /0

BracketStator

Brae/Yet BOri// for 06-37

mac/7. screws-74

14-

Prill far,shaft

BRACKET A 1._[.;4

Or& for shaft

(1i(3forli6V1 AtucKer "8" Dri/I for

,0(-376011

---Length of the sifea?'

When a variocoupler is to be mounted on a panel at apoint where the base cannot rest on the base board,quite a problem is presented. However, by making uptwo brackets from strip brass as shown at A and B above,the problem is readily solved. Bracket A is bent to theshape shown in the upper part of the illustration andclamped to the rotor and the shaft. Bracket B is boltedto the stator and alsd to the panel, thereby making a

rigid mounting. The shaft bearings are the panel andthe center hole in bracket B. -Guy Simmons, Jr.

933

LET US

TRAIN

YOU TO BECOME ANAUTO MECHANICAND ELECTRICIANAfter years of careful planning and research

we have developed a method whereby YOU maylearn to be an auto electrician and mechanic inyour own home.

Expert auto mechanics earn from $50 to $100per week. You can do the same. We can secureone of these positions for you.

No matter what your education may be ourengineers, Mr. E. W. Towne and Mr. A. Metela,will teach you thoroughly and quickly to becomeexpert in this line.

Each student will receive our personal attentionand individual help as required.

The benefit of our twenty years' experience isyours for the asking.

"Chicago's Best Automobile School" is the quo-tation that expresses the opinion of thousands ofsatisfied students.

For particulars write

SIMPLEX AUTO SCHOOLCHICAGO, ILLINOIS

1834-1836 West Van Buren Street

"How 'Became PopularOvernight!"

"They used to avoid me when I asked for adance. Some said they were tired, othershad previous engagements. Even the poor-est dancers preferred to sit against the wallrather than dance with me. But I didn't'wake up' until a partner left me standingalone in the middle of the floor.

"That night I went home feeling pretty lonesome and mightyblue. As a social success I was a first-class failure. At firstI wouldn't believe that you could teach by mail because I al-ways bad the ides, that one must go to a dancing class to learn.But I figured I could risk 10c-especially since you guaranteedto teach me.

How Dancing Made Me Popular"Being a good dancer has made me popular and sought after.1 am invited everywhere. No more dull evenings-no bitterdisappointments! My whole life is brighter andhappier. And I owe it all to Arthur Murray!

"I was astonished to see how quickly one learnsall of the latest steps through your diagrams andsimple instructions. I mastered your course in afew evenings, and, believe me, I surely did give thefolks around here a big surprise when I got onthe floor with the best dancer and went through thedance letter perfect. Now that I have the Murrayfoundation to my dancing I can lead and follow per-fectly and can master any new dance after I haveseen a few of the steps.

"My aster's family have all learned to dancefrom the course I bought from you, and it woulddo your heart good to see how fine her little kiddiesdance together after quickly learning from your newmethod of teaching dancing at home without music orPartner."

Learn Any Dance in a Few HoursWhether you want to learn the Foy -trot, One Step. Waltz

or any of the new dances, you won't have any trouble indoing it through Arthur Murray's new method. More than90,000 people have learned to dance by mail, and you canlearn just as easily.

Arthur Murray is America's foremost authority on socialdancing. Through his new improved method of teachingdancing by mail he will give you the same high-class instruc-tion in your own home that he would give you if you tookprivate lessons in his studio and paid his regular fee of$10 per lesson.

Five Dancing Lessons FreeBe sure as Arthur Murray that you will be delighted with

hie amazingly simple methods of teaching that he has con-sented for a limited time only to send FIVE FREE LES-SONS to all who sign and return the coupon.

These live free lessons' are yours'to keep-you need not re-turn them. They are merely to prove that you can learn todance without music or partner in your own home.

Posed by MissAnn Forest,

Famous MovieStar, and Ar-thur Murray

Write for the five lessons today-they are free. Just en-close 10c (stamps or coin) to pay cost of postage, Printing,etc., and the lessons will be promptly mailed to you. Youp ill receive: (11 The Secret of Leading. (2) How to Followsuccessfully. (3) How to Gain Confidence. (it A Fascinat-ing Fox-trot Step. (5) A Lesson in Waltzing. Don't hesitate.You do not place yourself under any obligation by sendingfor the free lessons. Write today.

ARTHUR MURRAYStudio 971, 290 Broadway, New York

Arthur Murray. Studio 971,290 Broadway, New York City.To prove that I can learn to dance at home in one evening

you may send the FIVE FREE LESSONS. I enclose 10c(stamps or coin) to pay for the postage, printing, etc.

Name

Address

City StateAlso at 150 Southampton Row. Loudon.


934

$3 brings genuine

UNDERWOODYes, only $3 down puts this genuine

standard Shipman -Ward Rebuilt Under-wood in your home. Then-small monthlyPayments, or if convenient, pay cash.Either way you get the world's standardtypewriter at a big cash saving.

WHY PAY RENTAL?Think of it! You pay little more than rental,

and the machine Is yours! We offer the samethree models of the Underwood Typewriterwhich are being made and sold by the UnderwoodCompany today. The only difference is thatShipmar -Ward machines are priced lower andare rebuilt like new by experts. You can't tellthem from brand new machines. Visible writing-the FULL LINE of typewriting is visible at alltimes. STANDARD 4 -ROW SINGLE SHIFT KEY-BOARD. Two color ribbon, back spacer, stencil de-vice, automatic ribbon reverse, tabulator, etc.

TEN DAYS' FREE TRIALSee for yourself! 'Pry the typewriter ten

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=FREE TRIAL COUPON.=Typewriter EmporiumViiiPMAN-WARD MFG.CO

2161 Shipman Bldg., CHICAGOSend by return mail Bargain Offer No.216Iof a Standard Visible Writing Underwood.This is not an order and does not obligateme to buy.

Name

Street or R. F D. No

Postoffice.

BANCEAndbe

PopularLearn In ONE HOUR at Home

There's now no need of being a wall-flower. In one hour-at home-by mail-I can make you an easy, confidentdancer-popular in any ballroom.

NEW EASYMETHOD

No Partner Needed-No EmbarrassmentOver 60,000 men and women have be-

come popular dancers of Fox Trot, OneStep, Waltz and all the latest up-to-the-minute society dance steps through my newFoto-tell and Fono-tell Method set tomusic. Amazingly easy-fascinating. Noother course like it. I teach you perfecttime and rhythm - the secret of gooddancing. Your success Guaranteed.

SENT FREE ON TRIAL-No A itConvince yourself at my expense how amazingly

easy it is to learn modern dancing with my newmethod. Fora short time only I'll send the firstsix lessons of my course (in plain wrapper), in-

cluding 10 -inch dance instruction record, freeand prepaid for live days trial. See, test andprove this remarkable new method in your ownhome. Then, if not delighted at your success,simply return record and leases. within five daysand you'll owe me nothing. Write quick beforethis phonographer expires. Please mention makeof you have.

WILLIAM CHANDLER PEAK, M. B.

4601-4611 Broadway Chicago, Ill.

rSend To -day for the"Electrical Worker's Friend"

R Ind lag- and reconnecting A. C. motors.inns with complete Instructions for re -

An electrical book of 66 motor draw- $

Special atOr write for full particulars of this valuable book.

SMITH & SMITH PUBLISHING CO.Dent. B., 7428 Hermitage St., Pittsburgh. Pa.

Unique Lightning Switch

fibre NocA-s,

to Antenna

Brossblock

Woodscrew

to groan

Brass rod

two clips ofspring brass

Windowframe

to set

11

Ping ofbrass

or copper

If a hole is drilled in a window frame and through a fibreblock screwed to the outside of the frame, and other mate-rial arranged as shown above, an efficient lightning protec-tion device will be formed. Two heavy spring brass clipsare so bent that they may be mounted as shown. A plugis then made which can be passed through the hole in theframe and the fibre block and which will separate the twoclips so that they will not touch the binding post which isconnected to the ground. When the plug is withdrawnthe clips close and clasp the binding post and the antennais grounded. With the plug inserted, the antenna is con-nected directly to the receiving set....David Kennedy.

Compact Double Switch

lJeBend andotted biles

Semi-circa/or i"cbrass strip

Se1- 1:

The units and tens switch on a variocoupler can be com-bined into one unit by following the data given above. Thedetails of the two switch arms are given at A and B andthe assembly is made as shown. A front view of thecompleted switch will be seen at the top of the above illus-tration. The short arm makes contact both with a row ofswitch points and with a semi -circular brass strip whichcompletes the circuit. The circuit of the long arm is com-pleted through the mounting. Arm B is fastened to thelarge knob so that it is insulated from the shaft.-EinarI. Rand.


Now to Ycllook - Up ATransmitter Button to

MaRe an EMicientLoud TaRker

A Transmitter button with a few drycells and a telephone receiver will make aremarkably simple and efficient loudtalker. A Microphonic amplifier of thistype is just the thing for use with a radioset. The weak music and signals may beamplified many times their original value.It is possible to entertain a large audiencewith a simple radio equipment if a trans-mitter button is used in the circuit as ex-plained in diagram A.

The cost is extremely low and the re-sults are comparable with those producedby highest grade of expensive loud talkers.

As may be seen in the diagram, twodry cells or a small storage battery areconnected in series with the transmitterbutton and a 4 to 75 ohm telephone re-ceiver. The transmitter button is securedto the diaphragm of the telephone in theradio receiving set. To accomplish thisproperly, scrape off the enamel (if dia-phragm is enameled) on the face of thediaphragm and solder the small hexagonnut supplied with the button to the exactcenter. Care should be taken that thethin diaphragm is not bent or otherwise

' ///:qh rex 4-73:ohm/phone receiver \

1500 Ohmrests. phone

4V/500 Ohm

(receiver

harmed. The transmitter button is thenscrewed into place. Connections, asshown in the diagram, are made with flex-ible wire. A horn may be placed over thelow resistance receiver if desired. Whenthe radio set is properly tuned and signalsare being received, the transmitter buttonis operated by the vibration of the dia-phragm of the receiver. As the receiverdiaphragm vibrates, the mica diaphragmon the transmitter button also vibrates.The carbon grains are compressed atvarying pressure; the current flowingthrough the local battery circuit is thusvaried and results in an amplification ofthe sounds in the low resistance telephoneloud -talker.

Diagram B, which includes a step-uptransformer, is to be used with loud talk-ing receivers of high resistance. The pri-mary of the transformers should have aresistance of about 75 ohms. An ordi-nary telephone induction coil will serveas the transformer in this circuit.

You can get the above -described trans-mitter button FREE in subscribing to"Practical Electrics Magazine" at $2.00per year (12 months). Send your sub-scriptions today.

Make all remittances payable to Prac-tical Electrics Co., 53 Park Place, NewYork City.

-Adv.



A Novel Tuner

Sectorsg/ued.-to pane/and

Pane/

B

PrimaryW/ /7a11/7g

-0/a/

Secondarywinding

hole /%7 pane/

By winding two coils on cardboard sectors and mountingas illustrated above, a serviceable and compact tuner wilresult. It may be connected either as a variometer

variocoupler as desired.-Walter Ridgwell.

Wave -Trap or Series Condenser

VARIABLECONDENSER

HONEYCOMBCOIL -

AERIAL POSTOF RECEIVING

SET

DEAD SWITCHPOINT

SWITCH

SWITCH

By connecting a variable condenser and a honey -comb coilwith a three point switch as illustrated above, either aseries variable condenser or a wave -trap may he used inseries with the antenna or the latter may be connected

directly to the set.-Philip M. Zimmerman.

Switch for Flewelling Circuit

OUTSIDE AERIAL

LOOP AERIAL-)

TOGROUNDGROUND

SERIES -PARALLELSWITCH

0

o

0005MF

TOSET

INDUCTANCE

On a Flewelling set it is often desirable to change fromaerial to loop or to ground alone. This may be accom-plished by means of a series parallel switch. All the con-

nections are shown above.-Arthur Landman.

Generations of travelers in Europe haveseen women washing clothes, like the womanin this illustration, on the banks of livers.

Back of every greatstep in woman's pro-gress from a drudgeto a free citizen hasbeen some labor-sav-ing invention. Backof most inventions inelectricity's progressfrom a mystery to autility has been the re-searchof General Elec-tric Company scien-tists and engineers.

Shall the river work--or shall you?

Too many women, abroad, arestill washing clothes like this.

They go to the river. OurAmerican rivers are beingtrained to come to us. Water-wheels drive electric genera-tors-thus water is suppliedto your home, and electriccurrent runs the washingmachine which has banishedso much toil.

935

GENERAL ELECTRIC

Here'syour opportunity. Radioneedsyou. Win success in thiS fascinating field_

Trained men in demand at highest salaries.Learn at home, in your spare time.

Be a Radio ExperfI will train you, quickly and easily, to design.construct, install, operate, repair. maintain, andsell all forms of Radio apparatus. My new methodsare the most successful in existence. Learn to earn

$1,800 to $10,000 a YearFREE Wonderful, home -construction. tube

receiving set, of latest design.Write for"Rad lo Facts" free. Engineer Mohaupt.

American Electrical AssociationDept. 61 4513 Ravenswood Ave., Chicago

IMPROVED GROUND CLAMP

Equippedwith

FahnestockPatent

WireConnectors

EasilyAttached

No Soldering-For Radio Use OnlyAT YOUR DEALERS.

FAHNESTOCK ELEC. CO.Long Island City, N. Y.

Insure your copy reaching you each month. Subscribe to Science and Inven-tion-$2.50 a year. Experimenter Publishing Co., 53 Park Place, N. Y. C.


936

and Now a Complete RadioReceiving Set

Consisting of

RadiogemPhoneand Aerial

$ 50Shipping Charges Prepaid to Any Point in the U. S.

This outfit is absolutely complete. Itincludes everything you need to hear theBroadcast Programs, market reports, timesignals, ship calls or land station messages.Nothing more to buy-no batteries or tubesneeded-no upkeep cost of any kind.

The Complete Outfit Consistsof Three Parts

(One)

The RADIOGEMThe simplest radio outfit made-yet as prac-

tical as the most expensive. A crystal receiv-ing set that you can operate and enjoy eventhough you know absolutely nothing aboutradio. You receive the RADIOGEM unas-sembled, together with a clearly written in-struction book, which shows you how toquickly and easily construct the set, usingonly your hands and a scissors. The outfitcomprises all the necessary wire, contactpoints, detector mineral, tube on which towind the coil, etc., etc. The instruction bookexplains simply and completely the principlesof radio and its graphic illustrations make theassembling of the RADIOGEM real fun.

(Two)

The GEMPHONEAn adjustable, 1,000 -ohm phone complete

with 3 -ft. cord-the first inexpensive adjust-able receiver made. The Gemphone is ofstandard type and made of the very bestgrade of materials throughout. The case ismade of turned wood, an exclusive featurewith the "GEMPHONE." This is respon-sible for its exceptionally rich, and mellowtone. Like RADIOGEM, the GEMPHONEis sold unassembled. Our Instruction pam-phlet shows how to assemble it in two min-utes, using only a screw driver.

(Three)

The AERIAL OUTFITConsisting of 100 ft. of standard copper

aerial wire and two porcelain insulators.

Complete Radiogem Outfit $ 2.50The Radiogem, only 1.00The Gemphone, only 1.00Aerial Outfit, only .50

Order Direct or FromAkron, Ohio Da!las, Texas

Federman's Dept. Store Cullum & Boren Co.Astoria, Ore. Texas Furniture & filter -

Cook & Foster age Co.Atlanta, Ga. Freeport, I.. I.

Miller's Dollar Store Alexander GoldBaltimore. Md. Hamilton, Ont., Canada

A. A. A. A. Co. Radio Supply Co..Boston, Mass. Hartford, Conn.

Radio Specialty Co. Sage Allen Co.Brooklyn, N. Y. Hawera, New Zealand

Levy Brothers H. H. BlakeWeber Talking Mach. Co. Havana, Cuba

Buffalo, N. Y. Compania RadiotelefonicaElec. Sup. & Equip. Co. de Cuba

Chicago, Ill. M. MassoneBarawik Co. Manuel Nodar, Jr.Home Supply Co. Radio NoveltyLevitus & Flansberg Hoboken, N. 1.

Cleveland, Ohio C. R. Prieman Co.Anderson Elec. Co. Laurel Springs. N. J.Service Publishing Co. Stone & Kean

$250 Com.plete

$ 00 WithoutPhone orAerial

(Patents Pending)

What They Say About RADIOGEMI am enclosing herewith $1.00 to pay for the Radio -gem. I had it carefully wound by our wirelessoperator and find that it works beautifully-fully asgood as any crystal set we know of.

Radiogem received, which we assembled and werevery much astonished at results obtained and theclearness and volume of tone produced.

The greatest distance I heard on one of your setsis 1000 miles, having heard WOY at Schenectady.N. Y. I think your set Is the best I have ever soldat any pries.

Herewith P.O.M.O. amt $1.00 for another "RA-DIOGEM." The one received is O.K. Placed about15 ft. of picture cord under front porch and ground.ed to a gas meter, and heard the Sacramento Beeand Sacramento Broadcasting Union much betterthan with my large crystal set.

Your RADIOGEM RECEIVER is a wonder. I havereceived every station in Philadelphia with it muchlouder than with a high-priced crystal set.

Your two Radlogem sets received last night, andone was wired up for testing. WOC is about 40miles away, and their signals could be heard withheadphones on table. After they quit KYW atChicago about 170 miles east was heard. Everyword could be plainly heard here.

You claim a radius of 20 miles over your "Radio -gem" is sometimes a possibility. You should ad-here to the truth. I constructed one for my mother,installed it with an aerial, and she listens not oncein a while, but at her will, to Schenectady. New-ark, New York. or Providence. R. I., and her homeis Attleboro. Mese. I can't give your set too muchpraise.

(Names end Addresses en Request)

the Following Dealers:Los Angeles, Cal. Philadelphia, Pa,

Lester's Radio Shoppe Jos. J. MillerMedford. Ore. Philipsburg, Pa.

Virgins Radio Service A. 0. CurtisMedia, Pa. Poughkeepsie, N. Y.

Media Elec. Co. Chas. P. RaymondMelbourne, Australia Providence, R. I.

Marks&Abrahams,Pty,Ltd. The Outlet Co.Newark, N. J. Pullman, Wash.

L. Bamberger & Co. Electric Supply StoreSaginaw, Mieh,

J. A. iouberi & Co.St. Louis, Mo.

United Auto SUMAS' Ce.St. Paul, Minn.

Hill District Radio SheetMetal Co.

Seattle. Wash.Frank B. Wilson

Springfield, Mess.Johnsons Book Store

Oregon City. Ore. Washington, D. C.Singer Hill Radio Service Chae. Kiaben Co.

New York City, N. Y.Dixie Supply Co.Eastern Radio Corp.Radio Specialty Co.Harold M. Schwab

Northampton, Mass.Parsons Elec. Shop

Norfolk, Va.F. J. Sawyer

THE RADIOGEM CORP., 66 -S -West B'way, N.Y. City

WANTEDRailway Postal Clerks$1600 to $2300 Year /-/ Franklin Institute, Dept E182, Rochester, N. Y.

MEN-BOYS 18 Up + Sirs: Send me without charge. (1) Sample Railway0 Postal Clerk Examination questions. (2) List of Gov -

Mail Coupon Immediately ornment jobs nowtwainoiable.

(3) Send free Mus-etasted book, "How to Government Jobs."

Steady work. No layoffs. Paid vacations.

Common education sufficient. / Name

Travel - See the country. / Address


Tapping Coils

In tapping a coil it is usually common practice to makea small loop in the wire and twist it slightly and continue with the winding. However, when coils are used

which do not have any parts within them, a much neaterjob will result if the taps are taken off as illustratedabove. Holes should be drilled in the tube at the pointswhere taps are to be taken off. The wire is then woundand when a hole is reached, a loop about five or more

inches long is made in the wire and pushed through thehole. At ,the point where the wires enter the hole, theinsulation should be scraped and the two points soldered.The end of the loop is then freed from insulation andsoldered to the switch point. A kink for fastening theend of the wire is also given above. Three holes aredrilled in the tube and the wire laced in and out throughthem so that it will hold itself. -Maynard J. Columbe.

An Efficient Grid Leak

-4V

AO \ I

'4

/loci/ head.

ay/ spring

Brass orcapper

Shalt/

1/75a/atitya/ack

igowiliky hales,

Pmci/ mark

An efficient variable grid leak is one of the most ellusi eof instruments and very seldom can be made to functionproperly. However, by following the constructional detailsgiven above, a variable grid leak will result which willhave very few of the drawbacks of the average type andmany advantages. One of the greatest advantages is thatit renews itself by placing carbon on the line which formsthe high resistance instead of scraping it away, as is doneby the usual type of contact. -T. L. Stalker.



Tremendous, big -paying opportunitiesare open for ambitious men in Mod-ern Photography. This is the pictureage. Magazine and newspaper pub-lishers buy thousands of photographseach year. Every manufacturer sendsout high priced pictures of his prod-ucts. Every home wants portraits.

Photography is a business run-ning into millions of dollars eachyear. And there is a great short-

.. age of trained photographers.

EARN $3,000 to 10,000 a YearHundreds of men are earningbig money and establishing theirown businesses. Even duringspare time, while training, youcan make $75 a week easily -no matter where you live!Amazing New Easy Method

I show you, at home, how to dethe kind of work turned out bythe big studios in New York andChicago! I show you how tomake big money within 30 days!C. M. Cole bought a home withmoney he bad made when onlyhalf way through his training.So well do I know what I can do

for you that I guarantee undermid to return every cent of your tuition if you are notthoroughly satisfied.

Professional View Camera FREE!WritO at once for Free Camera Offer-I give yoti, free, a splendid pro-fessional view camera. You will beastonished and delighted. This offeropen for short time only - so artquirk! No obligation.INTERNATIONAL STUDIOS, Inc.

Dept. 74513601 Michigan Ave., Chicago, U.S.A.

Got $100 forFlood Pictures -

"I took picturesof a flood andsold them for$100. I have beenable to buy myhouse a n d lotfrom the sale ofI ictures."

C. M. Cole,Washington.

$97 in Two Days!"I inade $235 inDecember. \Ventout two days lastweek n n homeportrait work and

wade $07."A. G. Hitches,

Kentucky.

COAST TO COAST

The best -yet simplest set made. Onedial controls everything. Endorsed byTribune Institute. Uses an ordinarydry cell battery. Takes all wave lengths.Royal Portable Receiver complete with phones,tube and aerial $19.75

Royal 2 stage amplifier; best type of amplideationfor our 1 tube set 17.50

Royal Ware Trap, improves considerably the selec-tivity and reception of any set 6.00

Get our catalog of Standard Radio Parts

ROYAL MANUFACTURING COMPANYDept. 27 World Building, N. Y.

ON ONETUBE

1;. \Iaefonaldof Bangor.Me.. heard

K ZV, Win a t

on the

ROYALPortable

Broadcast

Receiver

$10.°0

"B" BATTERIES51.75-22./2 v. $ .80$3.00-22'/, v. Large 1.35$3.00-45 v. 1.3064.00-45 v. 1.75$5.50-45 v. 2.75

STORAGE BATTERIES$18.00- 80 Ampere Hours $9.75$24.00-100 Ampere Hours $12.75$28.00-120 Ampere Hours $14.75

051ffi

tweRkeeltns Coll. 700 meters $1.45

I I5a

artz

5V 1co4K

APIrisri

t40

Phones $5.75phontaldwin S 1 n

8000 Ohm

5 ti °TP

I11Dr Seibt

1 .30

$4.2

13.00-180° Coupler. 700 meters 1.4818.00 -Audio Transformers, 10 to 1 ratio 4.25

$8.50-0/2 Volt Tube 2.95Indoor Aerials .85Three Tube Set -Guar. All Distances 40.n0One Tube Set -Operating Loud Speaker 22.00

SEND FOR SPECIAL XMAS BARGAIN LIST

Set of 3 Neutrodyne Transformers withNeutrolising Condenser ...$14.75$5 Gold Aerial 7 Str. $2.50$25 Loud Speaker $12.50$30 Musotone $16.

Useful Soldering Kink

The average soldering iron used by the amateur is much

to heavy for line work. If a piece of copper wire is

twisted around the iron and pointed at one end a useful

appliance for small work will be formed. The wire maybe of any length necessary to do the work on hand and

the healy soldering copper will keep it hot. -E. Rosewater.

Easily Made Template

Locate and markholes to be drilled

N

/ 1 \

T0,0 of variaoleC0/7 aenser

Sheet of celluloid

A sheet of celluloid may he laid over the top of a vari-able condenser and the locations of the various holes to

he drilled marked thereon. The holes are then drilled in

the celluloid and a template will result which will givevery good results for locating the mounting holes for thecondenser on the panel. -E. M. Abbot.

Vernier Rod

RUBBERHEADED

TACK

WOODENROD

8' LONG

KNOB

'A rod constructed as shown above may be used for turningthe dials on a receiving set by placing a rubber headedtack on the panel in frictional contact with the edge ofthe dial. -Edward L. Foote.

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Reducing Body Capacity

VARCOND_

ANY STANDARD TI

FILAMENT/CIRCUITGROUNDED

One of the greatest annoyances to the average amateur isthe effects of body capacity which are found when the handis brought near the tuning controls. This is particularlyannoying in tuning in DX stations. Sometimes even

shielding of the panel will not eliminate the trouble.Under such conditions it is advisable to try the kink illus-trated above wherein the filament circuit is groundzd. Thiswill very often eliminate trouble caused by body capacity,and make the set easier to tune. -Jack Kay.

Phone Tip Jacks

Par7e//

Spring

fig. 3

r-8

fig. 2

1" No/e/6

yov stemInner

vetube

cal' offfig i

Phone tip jacks are rather expensive to purchase, but canreadily be made by following the instructions given above.All the material required is the valve stem from an oldautomobile inner tube and a sheet of spring brass cut tothe shape shown in Fig. 2. The valve stem is first cutoff as shown in Fig. 1 and the hole enlarged for a distanceof about one -quarter of an inch as shown. The strip ofbrass is then bent as illustrated in Fig. 3. The twoparts are then mounted with a nut as illustrated. Itwill be found that the phone tip can be plugged into thehole and will make excellent contact with the spring brassstrip. -Warren Fleenor.



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Neutralizing Condenser

,-Double binding pasts..,.,Threaded rod

"234

43"

Brass tubeBakeki`e nnob

Threadea' baife/i/e knob

In the Neutrodyne circuit, very small capacities which canbe critically adjusted must he used. By following the abovediagram, a condenser results which will give good resultsand at the same time susceptible to close manipulation.

-L. Kranzl.

Loop Connection

LOOP AERIAL TO R FAMPLIFIER

TO AER1AL

JACK

001 MF VARIABLECONDENSER

VAR10- COUPLER

.TO GROUND

By connecting a loop to an ordinary phone plug and con-necting a twocircuit jack as shown, either a loop or an

outdoor antenna may be used as desired. Inserting theplug in the jack disconnects the antenna, ground and coup-ler and connects the loop in the circuit. -J. Phi Ilyss.

Bare Wire Coils

/are Copper wire

tube

Cotta,,chalk //he

Coils wound with bare wire are found to be very efficientin radio receiving sets, but spacing the turns is a rathertedious job. However, by first winding the coil with alayer of ordinary cotton cord and then winding the wire,an efficient coil will result in which the turns will be

spaced very evenly. -A. Ferrend.

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Changing Socket Slot

-A"" bailer! x 21" battery

z y

Plate GridA

CAW" for /77aPhltly posts afterchange of slot

ieff slatcu/ of

+ A1

- A2

Nate.7

Grid4

X 6 P -A +A

y -A 6 + A P

Z P +A 6 -A

gralrew hacIr saw,blade ground oft

o ...,...,./..10,- cuftmg slot

Where moulded sockets ale used it is often found tllathe slot into which the prong fits bends outward, and nolonger holds the tube securely. When this happens, newslots may be cut at points X, Y or Z and the bindingposts changed to the designations shown in the chart. Ahack saw blade ground as shown will give excellent resultsfor cutting the slots. Arthur Calkins.

Mounting Honey Comb Coils

Honeycombcoil

Wire ortape aaa

bloat

/54earahle e/ec-trio light plug

A separable electric lighting plate may he mounted asshown, one half on a honey comb coil and the other halfin a wooden block. An efficient variable honey comb coilmounting will result. The base of the plug may hecemented into the hole in the wooden block if a tight fitcannot be made. The wooden support should he keyedsolidly to the shaft. -C. W. Fancher.

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Filament Control Circuit

The standard filament control jacks are very difficult to connett, as many leads are necessary. If a double circuitjack and a single circuit, jack are used and connected aillustrated, they will function as filament control jacks veryefficiently. With the plug in the two circuit jack, thedetector will light when the rheostat is turned on. Withthe plug out, or in the other jack, both filaments willlight. -.Jason Crain.

Solderless Connections

Wire thrueye ofbinding post

Small binding posts may be fastened to ordinary taps takenfrom inductance coils and connections made thereto, therebyeliminating the necessity of soldering. At B is shown howtwo wires may be connected together by means of a bind-ing post. N. Loeb.

Variable Condenser Cleaner

By bending a pipe cleaner and inserting the ends into awooden handle as illustrated a cleaner will be made whichcan be run between the plates of variable 4condensers whichwill remove any dust or any foreign material which mightcause trouble by short-circuiting the plates. This cleanershould be used frequently to keep the condensers at maxi-mum -efficiency. -Charles L. Higgins.

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Such power, selectivity and ease of control, withthree tubes, are attainable only through Erla reflexdesign, incorporating Erla synchronizing radio andaudio frequency transformers.Guaranteeing the perfect synchronization ofreceived and reflexed currents having the samephase characteristics, Erla transformers enablevacuum tubes to do triple duty, as simultaneous am-plifiers of received radio frequency, reflexed radiofrequency and reflexed audio frequency currents.For complete details, ask your dealer for Erla Bulle-tin No.14, giving Erla one, two and three -tube reflexhookups. Or write direct, giving your dealer's name.

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APPEO POLESFOR PANEL,MOOTING

5150103POST

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This condenser marks a revolution in condenser build-ing. It is Use simplest and most practical type of con-denser as yet developed for broadcast and amateur work.This condenser has been developed by our engineersafter considerable research work and has been pronouncedPerfect by experts.

15 Outstanding Features1-Large capacity (.001 MI.). 2-Replaces a 93 -plate condenser. 3-Uses a minimum of space, size 3%"x21/2"x114".

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AND EXPERIMENTSwith instructions

K. ELECTRIC CO.15 PARK ROW NEW YORK


Vernier Condenser

Pane/

Rotor contact goring

SIM 0

A

Stationary,;ewer //ale

Rote be -hymn lock

nuts

c

3414\

Pane/ gushing

,Sivitcharts/ntopointer

Verniercontra/

A vernier variable condenser is one of the handiest instru-ments to place on a receiving set and an exceedinglysimple, yet efficient type may be constructed as shownabove. The variable condenser is partially dismounted andone of the stationary plate separators removed. Twothinner washers are then put in place of the separator, thetotal thickness of the two washers and the vernier station-ary plate to equal that of the separator. A rotary plateis clamped between two nuts on a shaft and mounted asshown. The regular condenser dial is then used for coarsetuning and the small vernier control when fine tuningresults are desired. -Harry F. Gammeter.

Mounting Switches

,- Switch armInsulating material

Hollow shafts,

k

Brass supportSwitch rod

;

Rotor controlling knob-''Switch control knob./

In order to eliminate the number of parts on a dial of aradio receiving set and at the same time centralize thecontrols, the switch points for controlling the inductancein the primary circuit may be mounted on a panel andfastened to the variocoupler as shown. The shaft on whichthe coupler secondary rotates must be hollow. Throughits center passes a rod which controls the switch arm.This red is rotated by means of the small knob.

-Stephen Goff, Jr.



Soldering Furnace

When an ordinary soldering iron is exposed to a gas oralcohol flame it usually becomes sooty and the tin is

sometimes burned off. This is done away with by makinga small soldering furnace as shown above. Place over agas flame. -John L. Kenickell.

Lock Filament Circuit

It is very annoying when, at times, it is found that in theabsence of the operator, the filaments of the tubes in a

radio set have been turned on and left burning. It is

possible to overcome this annoyance by connecting up a

Ford switch as shown above. By turning off the switchwhen leaving, it can be locked in position and one whohas no key cannot move it. -Kenneth Kesterson.

Dial Indicators

Neat and effective indicators of dial settings may be madefrom flat head machine screws by filing two slots in theirheads and mounting as shown above. If the heads arepainted black and the slots filled with engravers' white, a

much better looking job will result. -Edward W. Lens.

(Continued Oft page 945)

Model K(SHOWN ABOVE)

$29.50It is a two -tube outfit consisting of onestage of tuned impedance radio -frequencyamplification with a tuner and vacuum tubedetector.This radio -frequency receiver amyl I ties be-fore it detects, eliminates interference toa marked degree and has much more vol-ume than most one -tube eets.

Model MW(SHOWN BELOW)

$54.50The Model MW consists of the same high-grade units as our Model K, with the ad-dition of a two step audio -frequency am-plifier in a single beautifully finishedsolid mahogany cabinet. It is a four -tubeset, comprising one stage of tuned impe-dance radio -frequency amplification, detec-tor and two stages of audio -frequency.

943

Gets 'em FromCoast to Coast

Just like the sweet, mellow tones of a flute or violin floating infrom afar out on a lake-that's the way concerts come in through1,11RACO receivers-and-Not only front the nearby stations either. For our users tell usthat Cincinnati hears 'Frisco, Denver hears Schenectady, NewYork hears Havana! Scores of long-distance records were madeon these instruments last year so, with the many new refinementsincorporated, the results obtainable will he far better now than ever.

HIGHEST QUALITY AT LOWEST PRICEWhen the radio craze swept the country like a storm late in 1921,M IRACO was one of the first real successful sets to be placed onthe market. Highest quality at the hylvest pricehas always beenour keynote, and the thousands of sets now in use all over theworld are a fitting tribute to Miraco's excellent performance. Manynew improvements have just been made in the MIRACO Models Kand MW, such as new sockets resting on shock absorbing, pads is arefinement found only in the most expensive and elaborate sets.Improved rheostats with multiple resistance windings makes it pos-sible to use any type of tubes.and a new aluminum shield preventsannoying body capacity effects.The cabinet is of solid mahogany, workmanship throughout is thefinest while its operation is extremely simple yet always dependable.

Write for our new bulletinTODAY

DEALERS - JOBBERSWrite for proposition quickly.

AGENTSThere's still some territory open

-write or wire.

THE MIDWEST RADIO 09 MAIN STREETCO. CINCINNATI, OHIO

CATALOGPE Al 9G- 1E0s0

FREEEVERYTHING IN RADIOOne of the largest complete stocks in theworld. 40 diagrams of latest Hookups.

DEALERS ALL OVER THE U.S.Making big profits handling our supplies. 24 -hourservice. Goode shipped same day order received.

WHOLES iLE RADIO DISTRIBUTORSDept. F. 6 West 14th St. Kansas City, Mo.

BOYS! BOYS! BOYS*,,""H ROW

URVOICE

Into a trunk, under the bt.,1 oranywhere. Lots of Fun foolingthe Teacher, Policeman orFriend.

THE VENTRILO,a little instrument, fits let the mouth out

of slit, coed with above for Bird Calla, etc. Anyone can use it.NEVER FAILS. Also a 82 PAGE BOOKwhich gives full 1 natructions on Ventriloquism. Formula forSecret Wnting [Invisible Ink], 10 phoney Making Secretsand 10 BIG TRICKS ON MAGIC all for 1UROT. NOV. CO., Dept. 323 So. Norwalk, Coon.LARGEST and OLDEST Man Order House In Connecticut.

Insure your copy reaching you each month. Subscribe to Science and Inven-tion-$2.50 a year. Experimenter Publishing Co., 53 Park Place, N. Y. C.



The Complete Book ofAll Radio Information 00$PRICE POSTPAID 2

PRACTICAL ELECTRICS COMPANY

RADIO FOR ALLBy H. GERNSBACK

Editor 'Radio News," "Science andInvention" and "Practical Electrics"

With over 130 illustrations and diagrams, and 12photographs, 300 pages, size 81/2" .r 51/2".

What the novice in radio needs is a book in which he can get all the informationnecessary for him to understand radio telephony and telegraphy, to make or buy areceiving set suitable to his means, to know how to operate his set, and after he hasan understanding of the radio art, information that will enable him to advance andget the most out of his outfit. All this must ordinarily be dug out of text -books,pamphlets and government publications, but the aim of this book is to have all thedata and information that the beginner will need from the time that he takes up radio.It is a permanent, comprehensive reference book for the dyed-in-the-wool dabbler inRadio.

What the Book Is.A combination of a radio course for the novice in radio telegraphy and telephony with a refer-

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For the Beginner.The theory of radio carefully explained with drawings.Description of and instruction for operating instruments of receiving and sending sets, with all

picture diagrams of the wiring of the apparatus.How to make your own receiving set, costing from $3.00 to $50.00.How to read diagrams; for every picture diagram there is a corresponding technical diagram

twine the symbols instead of drawings.How to tune sharply and eliminate interference from other stations.How to protect your set from lightning and the laws regarding installation.Explanation of time and weather signals.

For the More Experienced Amateur.How to make a practical vacuum tube detector, two stage amplifier set costing less than $50.00,

that will work.How the radio compass works.All about underground aerials, loop aerials and directional aerials.Formulae for.finding wave length; miscellaneous formulae for finding capacity of condenser andothe_ instruments. Tables of wire resistances, wave lengths and their corresponding frequencies,approximate wave lengths for different aerials, tuning coil data, and much more invaluable in-formation.

Special Features.Lists of all the broadcasting stations in the United States and Canada for concerts, timesignals, weather reports, press, stock market reports, eta., with their call, wave length and timeof sending.Detailed description of Washington weather signals and their translation.Description of a modern broadcasting station and its operation.Large map showing location of all U. S. radio telephone broadcasting stations suitable forbanging up In radio room.Collection of miscellaneous radio information for the amateur.

In Other Words.The information that you ordinarily have to dig out of government publications, text -books,pamphlets, etc., is handily combined in this one book.

The New

Science and InventionIn Pictures

THE STORY IS TOLD IN PICTURESunder the new policy of SCIENCE& INVENTION. Comprehensive,timely and self-explanatory illus-trations make the NEW SCIENCE& INVENTION more interestingthan fiction.

SCIENCE & INVENTION combs theworld for scientific news. It isrepresented by correspondents atevery world capital, in every im-portant laboratory- in fact atevery place in the world wherescientific development or achieve-ment may occur.

EARLY A N D ACCURATE REPORTS,careful handling by its editorial

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Radio News"The Largest Radio Magazine

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GREATER IN CIRCULATION, numberof pages, articles and illustra-tions, it is the indisputable peerof radio magazines.

WHETHER You ARE a radio ama-teur, experimenter, dealer, manu-facturer or layman, you will findmuch in RADIO NEWS of interestand value.

RADIO NEWS keeps you in touchwith all new radio develop-

ments, new hookups, achievement:, apparatus and with thefield in general.

IF YOU HAVE ANY INTEREST WHATEVER in radio you shouldread RADIO NEWS every month. It will pay you to do it.

RADIO NEWS CONTAINS more articles by radio experts-morespecific information - detailed drawings - illustrations andnews-than is published in any other radio magazine.

EXPERIMENTER PUBLISHING CO.,53 PARK PLACE, NEW YORK

'EnClosed find dollars for

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SUBSCRIPTION RATESRadio News-One Year $2.50Radio News-Two Years 4.25Science & Invention-

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25 cents Per Copy



3

Radio Wrinkles(Continued from page 943)

Simple Connectors

Clip fits either71' batterytad, dry Ce// alb

,0051' or5orhy cofiotrtor

Ordinary paper clips of the type illustrated above make v rygood connectors for use on different radio apparatus. Theillustration shows how they can be used for clipping on to"B" batteries, machine screws, or spring connectors.

-L. B. Robbins.

VarioCoupler Bases

STATORWINDING

HOLES FORBINDINGPOSTS 's\

ROTORWINDING

SHAFT

SCREWHOLES

SCREW' HOLES FOR /HOLE BINDING POSTS

PLASTER OF PARIS BASEMOULDED IN SQUARE BOX

P aster of Paris makes a very good base for mountingvariocouplers and it may be made as shown above. Theholes for the binding posts and mounting screws should bemoulded directly into the base. The stator of the couplershould be put into place before the plaster of Paris sets.

Increasing Capacity.0ouNe pole, sii7g/e ihroir push

INCREASE/

PUSH

CAPACITYmeg

VARIABLECONDENSER

.0005 mid. .0005 info:

The capacity of a variable condenser may be increasedplacing in parallel with it a small fixed condenser oft esame capacity. This is connected with double -pole sing) -

throw switch which should preferably be of the push-pu Itype. By closing the switch, the total capacity will be

variable from .0005 to .001 mf.

zkaa sLOUD SPEAKER

ENTHUSIASTIC TESTIMONY straight from animpartial authority. Re -PRODUCTION is a

pct. The delicate overtones which give musicits roundness, resonance and timbre, are faith-fully re -born through the modern magic of thepatented "double diaphragm." This extremelyresponsive device is adjustable to the exact re-quirements of your set and individual receivingconditions. Write for Illustrated Booklet "7'"

Atlas Loud Speaker UnitWith Phonograph Attachment $13.50Without Phonograph Attachment . . $12.50

Letters From Users RequestedWhat have you accomplished with your Atlas

Amplitone? Tell use about it.

Sole Canadian DistributorsThe Marconi Wireless Telegraph Company

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ttloeMilvARVARVARVARVANNIV/WARVARVARVIIRWYSINIVAAvieW1SUM114/11104

Ask Your Dealerfora

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a

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unlimited Morse or Continental messages, at any speed, just as an expertoperator would. Adopted by U. S. Government, and leading Universities,Colleges and Telegraph Schools. 3 styles. $14 to $30. Catalog free.If you own a Radio Phone Set and don't know the Code, you are.4.

missing most of the fun.OMNIGRAPH MFG. CO. 22 Hudson St., NEW YORK

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HB 8HOUR if "14117aWallegSmall cash payment puts kill Constant Potential Outfit inyour shop. Your increased profits easily carry the small $20monthly terms, with good surplus besides. HB 8 -Hourservice builds trade, beats competition. An HO saves you$35 to $115 over any other outfit on purchase price alone.Sold on 30 days' free trial with money -back guarantee.HB Constant Potential saves current, labor and rental bat-teries. HB Patented Voltage Regulating Winding abso-lutely eliminates reversing. Write today for Bulletin :121.HOBART BROS CO., Box SI4, TROY. OHIO

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"Make Your Own" withCONSRAD PATTERNSNeutrod ne

9 Receiver.

PilitoPtrs Receiver

A Short Wor Rmym\.ativcrkt-eivrr

A Nl2 1

Detector and amplifier unitN

Phone Crystal Set

kPanel Type

r.r!

AReinartzRene,N24 iver.NO 5 A itsflex

ReceiverIIMI10 C014.111.111.1Mit SERIE,

COCIMAYMAIM

mewling. MOM

NO14 rAdio Formular.ind Iiiatrams

44riditionol

4; Their. o

11

A

man

vaseweeisfiaisiTvawsso.cs

How to Make aShort Wave Regenerative Receiver

This set was designed by a foremost radioengineer to faith the wants of an all-roundbroadcast receiver. It covers wave- 5calengths up to 800 meters

How to MakeDetector and Amplifier Units

This ',attests was designed for detector andamplifying units especially adapted for usewith our regenerative receiver. It is stronglyrecommended when the attachment of rAcea loud speaker to that set is desired. aid

How to Make a Cockaday ReceiverThe Cochaday four -circuit tuner is one of thelatest advancements in radio. Its main ad-vantage lies in the fact that the set can beadjusted to the highest point of regeneration,and tuning accomplished over a wide band ofwave -lengths without Use necessity for read-justing the regeneration control. .411 dimen-sions, size of wire, number of turns, etc.,are given leaving nothing to the 5c.imagination.

How to Make the S. T. 100This is a two tube and crystal dual amplifierbrought out by an Englishman, Scott -Taggart. This is a very stable circuit andabove all, very easy for the amateur to con-struct. Complete blue prints for 50cadrilling and wiring

14 Radio Formulae and DiagramsWith this packet you need never worry aboutschematic wiring diagrams, measurementsand radio tables. All formulas and cncdiagrams are printed on heavy paper. SOU.

20 Radiophone Diagrams and Hook -UpsThese diagrams shot, limn to get the best Pos-sible efficiency from the instruments you makeor purchase. They cover hook-ups from thesimplest to the roost complicated, in a wayUsat any amateur can understand and followwithout difficulty. Printed on heavy paper,2%1114 Inches. and together with KEYCHART OF SYMBOLS and pamphlet "Howto Read Diagrams", are contained socain a heavy two-color envelope

How to Make a Reinartz ReceiverThe original Reinartz Receiver is the mostpopular type of set in existence today due toits simplicity of operation and capability oflong-distance reception. Full directions forbuilding this receiver are given in thisfolder. Two blue prints and instructionpamphlet in two-color manilla envelope. Theconnections of the set are shown 50c aplainly.

All About Aerials and their ConstructionThese blue prints were made after practicalerection of each aerial, and point out hornsimple It is to erect not only the properaerial for your particular need, but how toerect this aerial in the most practical man-ner and at the least expense. Consists of12 blue prints 84x11 Inches and onefour - page instruction pamphlet84x11 inches.

How to Make

A Radiophone Crystal SetDesigned for those without technical knowl-edge. This set has a range of 30 miles.Packet consists of 4 page illustrated directionpamphlet and full size blue print (A,for drilling end wiring.

How to Make an Autoplez ReceiverThe long expected one -tube set that willwork a loud speaker. Will operate whereverplaced and requires but a ground connec-tion. Every station within its range is am-plified sufficiently for a loud speaker. Tun-ing is very simple, there being but two con-trols. Any tubes from the "peanuts" up tothe "big ones" can be used. This receiverknows no such thing as "critical hutmentadjustment " The complete plans consist offull sized blue print for wiring and drillingand also a four -page instruction pamph-let giving complete details even as 50cato tuning.

How to Make a Neutrodyne ReceiverThis pattern gives the complete assembly,wiring, adjusting and tuning of a five -tubaNeutrodyne receiver. This type of receivingoutfit was brought out after extensive ex-perimenting and is noted for Its very efficientradio frequency amplification. All the dis-advantages of ordinary radio receivers, suchas distortion and re -radiation are elimi-nated. The circuit is also noted for keepingthe tubes from oscillating. Put up in packet,with full size blue prints for drilling andwiring and four -page instruction 50capamphlet.

How to Make a Reflex ReceiverThe plans for the reflex receiver were gottenout only after considerable research work byour engineers. Most people have troublewith reflex receivers. It takes an expert tobuild one that will work satisfactorily. Thetrouble lies in the values of condensers, etc.,in the circuits. If they are incorrect. theset is a dismal failure. The construction de-tails of a reflex receiver, contained in thisfolder, are the results of their suc-cessful efforts. 50C.

Order Direct From These Dealers Or If Your DealerAbilene, Kans.

Union Elec. Co.Albany, Ga.

Lonsbergs Book HouseAkron, 0.

Itadloart Supply Co.Albany, N. Y.

Ilavens Elec. Co.Ignition Service Supply Co.Cooper & llotchkissKimball Bros.Peoples Radio StoreStandard Elec. Co.Wenger Bros.

Amsterdam, N. Y.Anderson Elec. Co.

Allentown. Pa.Bess Bros.Buchman Book Store

Altoona, Pa.Altoona Elec. Supply Co.

Anthony, Kans.LeRoy Hughbanks Rad. Co.

Astoria, L. I.Astoria Radio Shop

Atchison, Kans.Low & Blythe Elec. Co.

Atlanta. Ga.Capital Elec. Co.Millers Book Store

Atlantic City, N. J.Paramount Radio Co.Eastern Hdwe. & Sup. Co.Sport ShopJust Elec. Co.Sea Coast Radio Co.

Auburn. Me.G. L. Foss

Baltimore, Md.Jos. A. BeckerJos. M. ZamoisklWilbur Elea Co.liacharach Rosin Co.W. W. Hen tzchelS. B. BerkowichJoel GutmanHerdas Elm.Little Jnes Dept. OteroC. D. Kellert.1. MeyerMurdock CO.E. I. Rosenfeld SI CO.

Batavia, N. Y.H. F. Smith

Bethlehem. Pa.Lehigh Radio Ce,

Billings. Mont.Torgerson Bros.

Birmingham, Ala.Interstate Elec. Co.

Bluefield. W. Va.Burgess Elec. Co.

Boston, Mass.Atlantic Radio Co.Cutter & Wood Supply Ce.Seth Fuller Co.International Radio Corp.I.ewis Elec. SupplyF. D. Pitta Co.New Eng. Elec. Spec. Ce.Williams Book StoresJ. B. Hunter dia Co.Samuel J. BeckwithChandler & Farrffinar Co.A. P. Merchant Co.Eugene Proctor Co., Inc.Radio Sales & Service Ce.Farrington & ClarkBerman Radio

Bridgeport. Conn.Morison Radiophone PartsFlynn & PowerConn. Radio Supply Co.

Brooklyn, N. Y.A rthoraBrooklyn Radio Serv. Co.0. OlsenTollner Elec. Co.Bklyn. Radio CenterBobs Radio ServiceIlklyn Elm. Lamp & Nov.Born Hall RadioGlobe Radio & Bat. ShopHaag & Vince Co.G. HleinteichC. G. RosewallJ. StreiffDenmarksAmerican Phon. Exch.Arlington Radio ServiceBarneys Radio ShopBengo Elec. Co.3. D. CunninghamDelta Elec. Co.H. A. DietzDurkmans MUSIC StoreKelley & FeistHalpern Elee. Co.Kensington RadioE. C. & H. B. LagerholmG. MoskowitzG. Scharff Sons

H. Schur & SonVictor Radio Sport ShopWalker Elec. Co.Breuer Bros.20th Century Radio Co.March RadioM. UlrichB. HauptDavid M. IsaacStarr Radio

Buffalo, N. Y.McCarthy Bros. & FordRobertson Cataract0. Ulbrich Co.

Burlington, N. J.Burlington Elec. Co.

Butte, MontanaMontana Elec. Co.

Cambridge. Mass.Clapp-Eastham Co.University Book Store

Canton, III.Frank White & Bros.

Camden, N. J.Neisner Bros.

Carrollton. Mo.Carrollton Radio Shop

Centerville, Ia.H. E. Luther

Champagne. Ill.H. C. Swanell & Son

Charleston, W. Va.John It. Each

Charlestown, S. Car.S. C. Radio Shop

Charlotte. N. C.Smith Novotny Elec. Ce.Caroline Radio Co.

Chester, Pa.Neisner Bros.

Chicago.Harry Alter & CoBarawik Co.Beckley -Ralston Co.Chicago Radio App. Co.Elec. Appliance CO.Inland Elec. Co.Marshall -Field & Co.A. C. McClurg & Co.Montgomery Ward & Co.Newark Elm. Co.Henry Paulson & Co.Sears -Roebuck & CO.Chicago Cut Rate Book

Community Book StoreIzenstark Radio Co.Follett Book Co.McArthur Elec. CoP. 0. News Co.Max SteinE. J. StringosFireside Radio Co.

Cincinnati, 0.Midwest Radio Co.Milnor Elec. Co.Reuter Elec. Co.

Cleveland, 0.Radio Electric ShopRadio Eng. & Sales Co.H. Lesser & Co.Oliver C. SchroederRadio Sales & Rep. Co.

Columbus, 0.Hall Elec. Co.

Coraopolis, Pa.T. C. O'Donovan

Cumberland. Md.J. A. Fulton & Co.

Dallas. TexasHuey & Philip Hdwe. Co.Southwest Radio Sup. Co.Radio Equip. Co.

Denton. Tex.Evers Hdwe. Co.

Denver. Colo.Electrical Auto App. CO.Pratt Book StoreReynolds Radio Co.

Des Moines, Ia.H. W. KingIowa Radio Co.

Detroit, Mich.Federal Elec. Supply Co.Twentieth Century Radio Co.Crowley Milner Co.McCaulay Bros.Detroit Elec. en.Wolverine Radio Co.Northwestern Radio Co.

Duluth, Minn.Kelley Duluth Co.

Easton, Pa.F. & W. Grand Stores

E. Orange. N. J.Essex Radio ShopUnited Radio & Sport Shop

Elisabeth, N. J.H. Richmond & SonElizabeth Elec. Sup. Co.

Eureka. III.Klaus Radio Co.

Fergus Falls, Minn.Grande & Sether

Far Rockaway, L. I.Dunlap Sptg. Goods Co.Scientific Radio co., lux.

Flushing, L. I.The Electric Shop

Ft. Worth. Tex.H. C. Meacham Co.

Galveston. Tex.Galveston Wireless Sup. Co.

Gardner, Mass.Gardner Hdwe. Co.

Gloucester, N. J.Lenny's Variety Store

Granite City, Ill.Rosenberg Dept. Store

Great Bend, Kans.Great Bend Radio Co.

Greensburg. Pa.H. Hamilton

Hamilton, 0.Radio Co.

Hartford, Conn.Elec. Sup. & Equip. Co.F. & W. Grand StoresG. Fox & Co.

Havana, CubaDiamond News Co.Liberia de Jose Albele

Helena, Mont.Van Blaricom Co.

Hoboken. N. J.International Book StoreEagans Radio

Holyoke, Mass.Haskell Elec. Co.

Independence, Mo.The Melodian Co.

Hackensack. N. J.Wurtz & Fuchs

Jacksonville, FIR.Southern Elec. Co.Holt Elec. Co.

Jamestown. N. Y.Willis Switch & Inst. Co.

Jamaica Plain. Mass.Conrad Radio Co.

Jamaica. L. I.Scientific Radio Co., Inc.Merrick Elee. Co.

Jersey City. N. J.Arrow Elec. Co.

M. SchleinGuarantee Elm. Co.

Johnson City, Tenn.Bishop Elec. Co.

Johnstown, Pa.W. T. Grant Co.

Joliet, Ill.Juliet Book & Sta. Co.

Kansas City, Mo.Vulcanizers Supply CO.Donaldson Radio Co.

Lancaster, Pa.Radio Outfit. & Sup. Co.

Lawrence, Mass.Schwarzenberg, W.

Los Angeles, Cal.Leo J. aleybereS. California Elec. Co.West Radio Elec. Co.Radio Concert & Equip.Natick Book StoreProde Elec. Co.

Lewiston. MontanaChas. Williams

Lock Haven, Pa.Burkett Bros.

Louisville, KY.Sutcliffe Co.

Lowell, Mass.G. A. 11111 Co.

Lyons. Kans.R. I. Case

Maeon, Ga.J. W. Burke Co.

Memphis, Tenn.Street Elec. Co.

McKeesport, Pa.F. C. Wampler & Son

Milwaukee, Wis.Julius Andras & CoDewey Sport Goods CO.Badger Radio Co.

Minneapolis, Minn.Jacob Andressen Co.Findley Elec. Sup. Co.Nagel) Hdwe. Co.Reinhard Bros. Co., Inc.Sterling Elm. Co.Peerless Elec. Co.

Missoula, Mont.Missoula Elec. Sup. Co.

Montgomery. Ala.Alabama Radio Mfg. Ca.R. P. Rams

233 Fulton StreetPublishers of Consolidated Patterns

Formerly The Consolidated


Science and Invention for January, 1924 94i

Solve Your Radio Problemswith E Co. Books

How to Make Radio-Ptioue

Receiving SetsA non -technical book for the beginner. Givescomplete constructional data on the buildingof a complete Crystal Detector Set, TuningCoil, Loose Coupler and a Single AudlonTube Set with Amplifying Units. It fur-nishes all dimensions and working drawingsof every part that must be constructed bythe amateur. 98 pages, 26 illustrations.Bound in beautiful two-color cover. 25cSize. 519z71/2 in. Prepaid

Loud TalkersHow to Build Them

Gives complete data for building too dis-tinct types of loud talkers. One chapterdeals with improvised loud talkers, and givescomplete instructions on how to build suit-able horns for use in loud speakers of theBaldwin and other types. With this bookanyone can build a successful loud talker,equivalent to the commercial types, costing$10.00 or more. 48 pages, profusely

2n5c.illustrated. nrepaid

Radio Questions AnsweredThis book is proving as welcome to theradio public as our "100 Radio Hook-ups",which is now the fastest selling radio pub-lication on the market. "Radio QuestionsAnswered" was gotten up after a thoroughcanvass of dealers to find out which topicstroubled most of the amateurs. Almost 100questions are answered very fully and inlanguage so simple that even the most in-experienced layman can easily understand.Put up in the style which has made theE. I. books famous all over the world. 52lieges, 2 color cover, 25 illustra- errtions. Seragoie

How to Tune Your Radio SetCovers in comprehensive form, the fundamen-tal principles of tuning. The characteristicsof radio waves are fully described and illus-trated. Several chapters are devoted to theuse and functions of all radio apparata.The book describes how to tune such setsas the Reinartz, Flewelling, Neutrodyne,radio frequency amplifier receivers andothers. 52 pages, 25 illustrations. 25cPrepaid.

100 Radio Hook -UpsContains a varied selection of hook-ups fromthe simple crystal to the more elaborate cir-cuits. %lin a circuit for every requirement.Crystal hook-ups, combined crystal withradio and audio frequency amplifiers, non -regenerative, and regenerative vacuum tubecircuits with and without radio and audioamplifiers. Amplifier units. with straightjacks. filament and switching arrangements,pruner amplifiers. choke coil, resistance Coon -led and transformer coupled radio frequencyamplifiers. Includes all the latest types ofReflex, super -regenerative, super -Heterodyne,Neutrodyne, Reinartz. Flewelling,and Bishop. 52 pages, two-color cover &ogiroi

Radio Frequency AmplifiersShows the construction of the Radio Fre-quency Amplifying Transformer and givescomplete constructional data. It shows theapplication of Radio Frequency to amplifyingunits that the amateur may already possessand gives 15 hook-ups showing practicallyevery use Radio Frequency Amplifying Trans-formers can be put to. 32 pages, 15 illustra-tions. Rotund In beautiful two-color e3Cc.cover. Size, 55/,x75/, in. Prepaid.. Sofia

07 Here is Your Chance to Learn All You Can About RADIO t n7$ 1 W The $10.00 "RADIO READING COURSE" Special at 40 1 tAll the ,e, kilical details and a thorough explanation of radio receU-tion, written In easily understood, non -technical language by a fore-most radio engineer and inventor. The five Lecture Books with over100 graphic drawings give YOU the knowledge to intelligently buy,design, build, operate and maintain radio receiving apparatus. Tellsyou how to locate and correct troubles, how to make your apparatusmore efficient and gives you a thorough knowledge of radio science.This set of five handsome Lecture Books are a complete radio library.To own them is like having a trained engineer or instructor at your

side, answering questions. pointing the way. :No :natter what yourinterest In radio, take advantage of this attractive special offer andbe the owner of this fine set of books.

SEND NO MONEYBy special arrangement YOU can own this $10 Course comprised in theset of five books for only 81.97-If you act at once. Simply send usyour name and address. Upon receipt pay the postman only $1.97plus postage and the books are yours. The supply la limited soorder at once.

Cannot Supply YouMt. Vernon, N. Y.

Stephens SitupNashville, Tenn.

Zlbart Bros.Newark, N. J.

Bomberger & Co.Bassett Radio Sup. Co.Davis Elec. Co.Eddies Wireless Ex.Bannister & PollardEssex Mfg. Co.W. T. Grant Co.United Elec. Sup. Co.Priedmans Music Shop

New Brunswick, N. 1.Schneider Bros.The Elec. Shop

Newburgh, N. Y.Reuss & Davis

New Orleans, La.Interstate Elm Co.Nola Radio

Newport, R. I.Gen. II. Chase

New Haven, Conn.W. W. Gale & Co.

New York CityFenno & Co.Frank Radio Co.J. J. KelleherDavid Kilioch & Co.Liberty Radio Co.R. H. Stacy & Co.Manhattan Elec. Sup.

Overland Radio & Equip Co.Peerless Light Co.Radio Specialty Co.Stanley & PattersonViking Radio Co.The Winchester StoreArmy & Navy Dist. Co.Chamberlain Elec. Co.Economy RadioElec. Service Eng. CcGoldftnger Bros.Gimbel Bros.R. G. HaslingerHerbert & HuesgenAllied Radio Co.J. BelmuthJ. H. Bunnell & Co.Butler Bros.Carnahan & Dalzell. Ire.Bway. Radio Corp.

P. M. Dreyfus' Co., Inc.Delta Elec. Co.Fordham Radio Spec. Co.F. & W. Grand StoresJ. L. Lewis & Co.Lowe Motor Sup. Co.Rosa Radio StoresLive Wire Elec. Co.Marks Radiollodelis-8 StoresPhillips Sport Shoptchman Bros.A A. Elec. Co.Acme Radio Co.Am. Elec. Tech. App.Atlas Elec. Supply Co.Atlas Radio Co.Bergmaier Bros.Franklin Radio ShopJ. GablerGlobe Radio ShopHYgrade Elec. Co.International Radio StoreJ. KelleherStarless Hdwe. Co.Nassau Radio Co.Times Sri. Auto Sup. Co.TriggersAce Elec. Co.Baker & Taylor Co.Borough Elec. Co.Comb's' Elec. Co.J. EdelsonICey,tene Battery ServiceS. S. Kresge & Co.Lancers Radio StoreA. MarcusG. Ii. Masten & Co.Mentz StoreMilbro Radio & Elec. Co.Radio & Mech. Trad. Corp.Radio ParlorRadiophone Equip. Co.Rialto Elec. ShopSt. Marks Radio Co.K. R. SchullstromF. E. SilvermanWoelfer

WorksmanPerfection RadioCortlandt RadioJames GearA. J. Goldman

Send UsT. Eaton & Co.Progressive Book StoreS. AstorM. & T. Elec. Co.Borough Elec. Co.Marvel Elec. Sup. Co.0. It R.A. E. ZimmermanDavidson Radio Co.Mogul Elec. Co.Brunswick Supply Co.Stuyvesant Radio Co.Oscars RadioFordham Sup. Co.M. H. Elec. Co.The Heights Radio Sup. Co.Eclipse Elec. Co.Fordham Radio Co.Crescent Radio Co.Terminal Rad. & Mtn. ShopUnited Anchor Tire Co.Inter Clty Radio Co..tnsephsonRedifon Corp.Greenwich Radio Co.H. GoldsteinIsador Fajans, Inc.Grand RadioM. RubinHanes & Co.Madison Hdwe. StoreAmerican Radio Co.Electrical Eng. & Con. Co.

Niagara Falls, N. Y.H. Messersmith & Son.

Norristown, Pa.E. Si. Law

Oakland. Cal.Warner Itros.E. NI. Sargent Cc

Omaha, Nebr.Wolfe Elec. Co.

Onset. Mass.W. C. Spring

Passaic. N. J.J. L. DavidSimon Bros.Passaic Radio Shop

Perth Amboy. N. J.Smerling, J.Amboy Lighting Co.Amboy Radio

New York Cityand Sales Agents for E. I. Co. BooksRadio Call Book Company, Inc.

His NamePaterson. N. J.

Federal Radio & Elec. Co.Pawtucket, R. I.

Delancey Fetch & Co.Peoria, Ill.

Peoria News StandPhiladelphia. Pa.

Gimbel Itros.H. C. Roberts El. Sup. Co.Sayre Level Radio Co.Goetz Music StoresF. & W. Grand StoresIt. P. Noll & Co.Trilling & MontagueNeisner Bros.Schltnniel Elec. Co.Radio Sales Co.John Wanamaker

Phoenix. Ariz.Nielson Radio Sup. Co.

Poughkeepsie, N. Y.C. P. Raymond

Pittsburgh, Pa.Goldsmith & Son Co.Ludwig Hommel & Co.Gain -a -Day Elec. Co.Liberty Incan. Sup. Co.Pitts Radio & App. Co.U. S. Radio Co. of Pa.Doubleday Hill Co.

Pittsfield, Mass.W. T. Grant Co.

Plainfield, N. J.II. It. Gayle Hdwe. Co.

Plattsburgh. N. V.H. E. Atwater

Portland, MeChisholm Bros.

Portland, Oreg.E. L. Knight Co.Hynson Elec. Co.Hylands Old Book Store

Pottstown, Pa.T. S. Reidenhour & SonPottstown Radio Sup. Co.

Princeton. N. J.Princeton Cycle Shop

Providence, R. I.B. & H. Supply Co.R. I. Elec. Equip.The Shepard Co.The Outlet Co.

ANSWERED

RADIO FREQUENCYAMPLIFIERS

AND 1-lOnITOMAKETHEM

HOW TO MAKERADIO -PHONERECEIVING SETS i

HOW TO TUNEYOUR RADIO SET

100RADIO

HOOKUPS

LOUDTALKERSHOW TO BURP THEM

11 WINFIELD SECORL

THE C. co.

PRICE25C

and AddressBoston Store

Reading. Pa.F. & W. Grand Stores

Rochester, N. Y.Hickson Elec. Co.Rochester Elec. Sup. Co.Wheeler Green El. Sup. Co.Eastman Radio Co.R. Schmidt & Co.E. C. Sykes & Co.Neisner Bros.Miller Drug & Elec. Co.

Ridgewood. L. I.Ridgewood Radio Shop

Rock Island. III.H. E. Gelhart & Co.Beardsley Specialty Co.Valle Co.

St. Joseph, Mo.Empire Elec. Co.Mannschrecks Book Stores

St. Louis. Mo.The Benwood Co.Linn:, Elec. Supply Co.Foster Book & Cigar Co.

St. Paul. Minn.North-West Elec. Eq. Co.Premier Radio Mfg. Co.Pioneer Elec. Co.St. Paul Book & Sta. Co.Crist Book Shop

San Francisco. Cal.Richter. Cnniad

Schenectady. N. Y.Albany St. Radio StoreJ. Tiger

Seattle, Wash.F. B. Wilson

Stamford, Conn.Arthora

Stillwater, Okla.Stillwater Elec. Shop

Syracuse, N. Y.Grant's Alexander SonsHughes Radio Corp.M. H. Salmon Elec. Co.

Toledo, 0.Ktiehter Radio Co.W. J. Nagel Elec. Co.Aitken Radio

Toronto. Oct., Can.H. M. KippT. Eaton & Co.

Trenton. N. J.Fieron & Son. Inc.Radio Chain Stores

Troy, N. Y.L. H. Cooper & Son

Tyler, Tex.R. E. Bryan

Union Hill. N. J.N. W. Friedman

Uniontown, Pa.Frederick Piano Ce, W. F.

Utica, N. Y.Dent, Co.. M. F.Olds Book StoreUtica Elec. App. Co.Utica Elec. Sup. Co., Inc.

Waco. Tea.Jackson's Radio Eng. Lab.

Washington. D. C.Continental Elec. & Sup. Co.Radio Auto Sup. Co.

Watertown. Wig.D. & F Kusel Co.

Watertown, N. Y.F. A. EmPsall & Co.

W. Hoboken. N. J.The Heraco Exchange

W. New York. N. J.W. N. Y. Heraco

Wheeling, W. Va.Gee Electric Co.

Wapakoneta. OhioHeine & Nagel Elec. Co.

Waupaea. Wis.Waupaca Radio Sale. Co.

Wausau, Wis.Janke, Kurth Co.

Wilkes-Barre. Pa.Foster Radio & Elie Co.

Wilmington. Del.I. X. L. RadioL. P. MooreWilmington Elec. Spec. Co.

Worcester, Mass.Neisner Bros.

Williamsport, Pa.Wilhelm Book Store

Yonkers, N. Y.Knepfer, F.Westchester Elec. Eq. Co.

York, Nebr.Bullocks

Youngstown. Ohl'Robert F. Phillips

radsad



Opportunity Ad -letsOU will find many remarkable opportunities and real bargains in these columns. It will pay you to read and investigate the offeringsmade every month by reliable firms, dealers and amateurs from all over the country. No matter what you may be seeking, whether

PPiles, automobile accessories, the opportunity to make money, or anything else, you will find listed here the best and most attractivespecials of the month.

Advertisements in this section twelve cents a word for each insertion. Name and address must be included at the above rate. Cashshould accompany all classified advertisements unless placed by an accredited advertising agency. No advertisement for less than 10 wordsaccepted.

Ten per cent. discount for 6 issues. 20 per cent. discount for 12 issues. Objectionable or misleading advertisements not accepted.Advertisements for the March issue must reach us not later than January 15.

The Circulation of Science and Invention is over 160,000 and climbing every monthEXPERIMENTER PUBLISHING CO., INC., 53 Park Place, New York City, N. Y.

Agents Wanted

Agents-Best seller; Jem Rubber Repair for tires andtubes; supersedes vulcanization at a saving of over 800 percent; put it on cold. It vulcanizes itself in two minutes,and is guaranteed to last the life of the tire or tube; sellsto every auto owner and accessory dealer. For particularshow to make big money and free sample, address AMASONRubber Co., Dept. 601, Philadelphia, Pa.

Big money and fast sales. Every owner buys goldInitials for his auto. You charge $1.50; make $1.35. Tenorders daily easy. Write for particulars and free samples.American Monogram Co., Dept. 71, East Orange, N. J.

Make $25 to $50 week representing Claws' Famous Phila-delphia Hosiery, direct from mill-for men, women, children.Every pair guaranteed. Prices that win. Free book "Howto Start" tells the story. George Claws Company, Desk 27.Philadelphia. Pa.

Wonderful Invention-Eliminates all needles for phono-graphs. Saves time and annoyance. Preserves records.Lusts for years. 12,000,000 prospects. $15.00 daily. Freesample to workers, Everplay, Desk 17. McClurg Bldg..Chicago.

We want Salesmen and Agents, either whole or side line.to sell our low priced radio books to the trade. Eminentproposition for live wires. The E. I. Company, Publishers.333 Fulton Street, New York City.

Write and learn hew to start profitable business withoutcapital or experience. Silvering mirrors, refinishing autoheadlights, tableware, plating. Outfit furnished. Inter-national Laboratories. Dept. 25. 309 Fifth Ave.. New York.

Earn big money fast applying gold initials to autos.Every owner buys-$1.35 profit on $1.50 sale-particularsand samples free. Write quick. Lithogram Co., Dept. 19,East Orange. N. J.

Only one sale a day means $200 per menet Flee solos.$1,000 per month! Marvelous new adding machine. Retails$15. Work equals $350 machine. Adds, subtracts, multi-plies, divides automatically. Speedy, accurate, durable,handsome. Five-year guarantee. Offices. stores, factories.garages, buy one to dozen. A fortune for live agents.Write quick for protected territory and free trial offer.Lightning Calculator Co.. Dept. W., Grand Rapids. Mids.

$60-$200 a week. Genuine Gold Letters for storewindows. Easily applied. Free samples. Liberal offerto general agents. Metallic Letter Co.. 441 B. North Clark.Chicago.

Agents-$15 a day-Easy, quick Sales-Free Auto -111gweekly bonus - $1.50 premium Free to every customer.Simply show our Beautiful. 7 -piece, Solid AluminumHandle Cutlery Set. Appeals instantly. We deliver andcollect. Pay daily. New Era Mfg Co., 803 Madison Bt..Dept. 880, Chicago.

Aoents-Big returns, fast office seller; partieulsro andsamples free. One Dip Pen Co., 12 Dalt, Retard Bldg..Baltimore, Md.

Rummage Sales make $50.00 daily. We start you. Rep-resentatives wanted everywhere. Wholesale Distributors,Dept. 32, 609 Division Street, Chicago.

Earn $10 daily silvering mirrors, plating and refinishingmetalware. chandeliers, bedsteads, headlights. Outfits fur-nished. N. Deets Laboratories. 1133 Broadway, New York.

Agents-Our soap and toilet article plan is a wonder; getour free sample case offer. Ho-Ro-Co.. 2719 Dodier. St.Louis.

We start you without a dollar. Soaps, Extracts, Per-fumes. Toilet Goods. Experience unnecessary. CarnationCo., Dept. 232, St. Louis.

A business of your own; Make sparkling glass nameplates, numbers, checkerboards, medallions, signs, big illus-trated book Free. E. Palmer, 313, Wooster, Ohio.

Agents Wanted to Advertise our goods and distribute treesamples to consumers; 90c an hour; write for full particulars.American Products Co., 1538 American Bldg., Cincinnati. 0.

New Wonderful Seller. Over 100 per cent profit on everysale of Harper's Ten -Use Set. Needed in every home.Washes and dries windows, sweeps, scrubs, mops. etc.Greatest year 'round seller. Write Harper Brush Works,152 -2nd St., Fairfield, Iowa.

Rug Salesmen-Get next to the biggest seller of the year-Loomrite Felt Rugs. Sell at sight at $2.50, cost $15dozen. Big, complete Rug Catalog, Free. Maieley-PayneMfg. Co., 104-S Hanover St.. Boston, Mass.

Agents sell Wolverine Laundry Soap. Wonderful repeaterand good profit maker. Free Auto to hustlers. WolverineSoap Co., Dept. B46, Grand Rapids, Mich.

Start your own business as our sole agent, selling 380famous home products. All or spare time. Dr. BlairLaboratories. Dept. 535. Llnehburg, Va.

500 Percent Profit: Free Auto. Whirlwind Seller. Tre-mendous Repeater. Sample Free. Barterer Products1943-8 Irving Park, Chicago.

Agents Wanted (Continued)Formulas. Processes, Trade-Secrets-Different, depend-

able, profitable. Catalog free. D. Thaxly Co., Washington,1). C.

An agent wanted in every town to sell double -suctioncups. For sample and full details send ten cents. HawaiianRolling Bar Co., Sayville, N. Y.

Every person playing Hawaiian guitar should use aRollers -Royce Rolling Bar. They don't slide, they roll.Agents wanted. Hawaiian Rolling Bar Co., Sayville, N. Y.

$10 daily silvering mirrors. plating ana refinishing lamps.reflectors, autos, beds, chandeliers by new method. Outfitsfurnished. Write Gunmetal Co., Ave. D, Decatur. Ill.

Agents Wanted Full or Part Time To Sell on liberal com-mission new Thermostatic Automatic Carburetor control At-tachment for Ford cars. Increases mileage 100 per cent. Noholes to drill. Attached in 2 minutes. Does automaticallyexactly what Ford Manual instructs driver do by hand.Cadillac now using Thermostatic Carburetor Control underBlancke license. Write at once. A. C. Blancke & Co.,Dept. 21 602 W. Lake St., Chicago.

Start clean business manufacturing our Acme DoughnutFlour. Makes pure, wholesome, delicious doughnuts. ReadySales. Full directions Two Dollars. American CerealCompany, Everett, Washington.

American Made ToysManufacturers on large scale, also homeworkers, wanted

to manufacture Metal Toys and Novelties, Barking Dogs.Wag -Tail Pups. Wild Animals, Automobiles, Indians, Cow -Boys, Baseball Players, Cannons, Toy Soldiers, CrowingRoosters. Statues of Liberty, Miniature castings of Capitol,Bathing Girl Souvenirs and others. Unlimited possibilities.Guaranteed Casting forms furnished manufacturers from$5.00 up, with complete outfit. No experience or machinerynecessary. Hundreds made complete per hour. We buygoods all year and pay high prices for finished goods. Cashon Delivery. Contract orders placed with manufacturers.Enormous business waiting to be taken care of in 1924.Catalog and information free. Correspondence invited onlyif you mean business. Metal Cast Products Co., 1696 Bos-ton Rd., New York. Established since 1912.111111111110MMINI

A utomobiles

Automobile owners. earagemen, meehanies, send for freeespy America's popular motor magazine. Contains helpful.money -saving articles on repairing, overhauling, Ignition,carburetors, batteries, etc. Automobile Digest, 541 ButlerBldg., Cincinnati.

renvertemenerremerrrese,

Battle Photos and War RelicsFor Dens: Relics Collected from Europe's Battlefields.

Firearms, medals, helmets, etc. Illustrated catalogue andsample War Photographs 25c. Lieut. Welch, 2117 RegentPlace, Brooklyn, N. Y.

Books

Free-Upon request will send you my literature illustrat-ing tho following books. Astrology. Character, Clairvoyance,Concentration, Healing. Hypnotism, Magnetism, Medium -ship, Personal Magnetism, Personality, Physiognomy. Sales-manship, Seerthip, Success, Sex, Will. Yogi Philosophy,Gazing Crystals, etc. A. W. Martens, E.E. 6, Burlington.Iowa.

"Lights, Colors, Tones and Nature's Finer Forces," in-cluding Vibrations; Odic -Auras; Electro-Magnetons, Cold -lights; Radio; Coming Inventions, 270 pages. SatisfactionGuaranteed; $2.00, Circulars Free. Stevens Research Lebo-ratories, 242 Powell Street, San Francisco, Calif.

Perpetual Motion, by Percy Veranee. A history of theWorts to discover same from earliest days to the present.together with a scientific discussion ding the possi-biliM of Its ultimate achievement. Profusely illustrated,357 pages. Price postpaid, $2.00. The EnlightenmentBosnian., Co., 305 Fourth St., Edwardsville, Ill.

Diseases and Their Innate Healer. Book 50 cents.Arthur Stevens. Wauseon. 0.

"Master Key" $2.50. "Power of Will" $3.00. Coue's50c. Phipps, 1014 Belmont, Chicago.

Hypnotism Astounds, eontrels. Wants gratified. 25 easyLessons $2.75. "Mindreading" (Any distance) Wonderful.Genuine. Guaranteed $2.75. "Book of Wonders, Mysteriesand Disclosures" $20.00 worth for $2.00. All three $5.00.Catalogs free. Science Institute, SV1014-Belmont, Chicago.

Shwa Quickly Produced. Self or others. Infallible.Priceless. Guaranteed $1.10. "How to Live Right" 10c."Way to Win" 10c. Prof. Deprado, EIV357 Oak, Chicago.

Business OpportunitiesSell us your spare time. You can earn Fifteen to Fifty

dollars weekly writing show cards at home. No canvassing;pleasant profitable profession, easily, quickly learned by oursimple, graphic block system, artistic ability unnecessary; weinstruct you and supply work. Wilson Methods, Limited,Dept. 51-81, Toronto, Canada.

You can have a business -profession of your own and earnbig income in service fees. A new system of foot correc-tion: readily learned by anyone at home in a few weeks.Easy terms for training, openings everywhere with all thetrade you can attend to. No capital required or goodsto buy, no agency or soliciting. Address StephensonLaboratory, 18 Back Bay, Boston, Mass.

Stop Plodding! Be Sueeessful. Operate a Tire RepairShop. Make big profits in any locality. We teach you andfurnish complete equipments $100 up. Book of Opportunityfree. Ilaywood's 1312 South Oakley Avenue, Chicago.

Wanted-County Distributors for World Fastest SellingAutomobile Accessory. Write A. Benross Co., 384 East144th Street, New York.

$50 to $150 Weekly Writing Yokes, Epigrams and Humor-ous Stories for publications. Write for details. AmericanInstitute of Humor. Office E. 414 Park Bldg.. Cleveland,Ohio.

Dollars yearly In your baekyard. No mushroom dope.Particulars free. Metz, 313 East 89th, New York.

For $5 we'll write three catchy, classified advertisementsthat will simply have to bring you business. We'll namerates of most profitable magazines, how to use them,etc. Martinek Company, 54 Humphrey Street, Corona, N. Y.

Free Book. Operate little Mail Order Business homeevenings, Pier, 515 Cortland St.. N. Y.IIIIIIMMIMMTM.11111311911111MT1111

1110111111

Chemistry

Learn Chemistry at Home. Dr. T. O'Conor Sloane,noted educator and scientific authority, will teach you.Our home study correspondence course fits you to take aposition as chemist. See our ad on page 917 of this issue.Chemical Institute of New York, 66 W. Broadway, New YorkCity.

Any Product. formula. duplicated, improved, cheapened.Harding, P.O. 1029, Chicago.

Experimenters. We carry a complete supply of chemicalsand glassware for your laboratory. Catalogue 5c. NationalScientific Supply Co.. 241 Pa. Ave., Washington, D, C.

Experimental Chemicals and Apparatus. Price list 5c.George Ott, 1218 Chestnut St., Reading, Penna.

Chemical Laboratory Supplies. Catalog 5 cents. UnionLaboratory Supplies, 518 Syms St., West Hoboken, NewJersey.

Chemicals-Amateurs and Experimenters, we can supplychemicals and apparatus that you need. Prices reasonable.Write for list. Midwest Chemical Co., 2752 Armond Place,(rear) St. Louis, Mo,

Correspondence CoursesCorrespondence courses sold complete, 1/3 usual prices

because slightly used; easy terms; money back guarantee.All schools and subjects. Write for Special Free Catalog.Courses bought for cash. Economy Educator Service, H202West 49th St. New York.

Used correspondence courses bought and sold. Bargaincatalogue 1000 courses free. Students' Exchange, Dept. 4,47 West 92d St.. New York.

Used Correspondence courses of all schools sold, rentedand exchanged. New 1924 catalogue free. (Courses bought).i.ee Mountain, Pisgah, Alabama.n11011TIMM110111111111111117111111111MIMMT.111111111111=111MMINIMIIIIIIIIIIMIIIIIIIMill

Duplicating Devices"Modern" Duplicators save Time, Labor and Moser.

Gets Business. Reproduces Typewritten or penned letters,Drawings, Lessons. Music, Menus, Bids, Notices, Sped-fleations. Maps or anything in one or more colors. Printstwo per minute. Special Sale On. 30 Daya' Free Trial.$2.25 up. Booklet Free. B. J. Durkin -Reeves Ca, PlUs-burgh, Pa.If fff/WI4141311111111111111.1111*

Ford OwnersSport Can. Fast, saner, hug the turns and stick to MN

mad-snake you glad you're a Ford owner. Can easily bebuilt by aid of life size "Red -I -Hut" patterns and Virtuesinstructions. The "Pal" delivered complete withPressed metal streamline all for $6.40. G men makebig money building them. Send for prospectus en makingsport ears-Jifdy Tops and Gosum windshields. SuelalielCe., 1100 Huompol Bldg., Guttenberg. Iowa.



Exchange

Gundlash Telescope, three inch objective lens. seventydollars. real bargain. Edward Prentice, Binghamton, N. Y.

For Sale. Complete outfit for the manufacture of RadioVariable Condensers, including dies, jigs, parts, finishedand unfinished condensers. Exceptionally cheap. Write fordetailed information. Zeunert Mfg. Co., 1752 North ParkAve., Chicago, 111.111/.111111111111 ?????? 111.111111111111/Milm1111111/11111111111,1111111.7111,111,111111,1r11111111111111111,11111111111110111,11

For InventorsPatent Application, including one sheet drawings, prepared

for $15. Further particulars. Arthur AL Benner, Olympia,Washington.

Get your own patents. Application blanks, complete in-structions $1. Cutting Bros., Campbell, Calif.

Your Chemical problem solved and working process fur-nished for Five Dollars. Write me. W. Stedman Richards,Consulting Chemist. Box 2402, Boston, Mass.

Specialized service for inventors. You furnish the idea,we'll work it out. Expert machine designing. Drafting.Opinions given on practicability of ideas. Confidential deal-ings. Your ideas fully protected. Write for full particulars.Otis Engineering Co., Desk EF, Omaha, Nebraska.MIIIITIMIORINIMINTIXIIFFIR11111111111411111.1.1111111111

FormulasMoneymaking Books, Plans, Formulas. Catalog Trom.

Ideal Book Shop, 5501-Z, North Robe), Chicago.

For the PhotographerHave you a Camera? Write for free sample of our big

magazine, showing how to make better pictures and earnmoney. American Photography, 118 Camera House, Boston,17, Mass.

Games and EntertainmentTasks. Puzzles. Jokes, Mesital Apparatus,Plays. Stags

S upplies, Mind -Reading, Acts and Sensational SAMOSBend 10e for 160 -page illustrated 1933 professional sats-umas Oaks Magical Co. Dept. 549, Oshkosh. Wis.

HealthStudy Sexology-Publication dealing forcefully wffh the

vital problems of intimate marital sex life will be sent onreceipt of 20c-Health and Life Publications, Dept. 108.1133 S. Dearborn Street Chicago, Illinois.

Free to Men-Information of a selentitle nature CM gmbrought physical vigor and happiness to thousands. No*ergs; no obligation. Enclose stamp fee rely. C. 1.Wood ik Co.. Colorado Springs, Colorado.

Help WantedWe want salesmen and Agents, either whole if side line

to sell our low priced radio books to the trade. SuellenProposition for lire wires. The E. I. Company.IPUNISOON.233 Fulton Street, New York City.

fleteetIves Earn Big Money. Travel. EICO1100i oppes-Sanity. Great demand everywhere. Experience unneelesare.Particulars free. Write, American Detective System. 1974Broadway. N. Y.

Get posted-Gond prices paid for butterflies, insects. SeeSinclair display advertisement, page 932.

Railway Postal Clerks-Start $133 month. Railroad pass;expenses paid; questions free. Columbus Institute, H-9,Columbus. Ohio.

Bo a DeteetIva; Excellent opportunity: good pay: travel.Write C. T. Ludwig. 1417 Westover Bldg.. Kansas CM.Ms

Make Mossy In spare time mailing lettere. Rare mei-:unity now. Men, send add d envelope for opesial OklaNormande 11, 197 W. 23d St.. New York.

All men, women. boys. girls. 17 to 65, willing to motGovernment positions. 91174250, traveling or stationary.write Mr. Clement. 293, St. Louis. Mo., immediately.

Silvering Mirrors, French plate. Easily learned. linmeson profits. Plans free. Wear Mirror Works. ExcelsiorS prings, Mo.

Earn $25 Weekly. spare time, writing ter nowerapers,magazines. Experience unnecessary; details (tee. massS yndicate, 5665 St. Louis. Mo.

Firemen, Brakemen. Baggagemen, Sleeping eat trainporters (colored). 81404200. Experience unnecessary. 897Railway Bureau, E. St. Louis, Ill.

U. S. Government wants help. Men -Women 18 up. $92-$250 month. Steady. Vacation, influence unnecessary. Listpositions free. Write immediately. Franklin Institute,Dept. E24, Rochester, N. Y.

South America Needs skilled help. Write EmployersDirect. 388 Addresses Si. South America InformationBureau, Portend, Oregon.

Wanted-Railway Mail Clerks. $1000. Experience orcorrespondence course unnecessary. Write, Mr. Selby. D78,Willow Hill, Ill.

lllllll 4.111114111 llllllll 111110111 llllll 11.11111111111011.1110111111

Improved Made ToysWanted Manufacturers and Houseworkers to manufacture

Metal Toys and Novelties. Wonderful opportunity. Mil-lions needed. In Whistling Birds, Wild Animals. Wag Taill'upe, Crossing Roosters. Automobiles, Baseball Players.Statue of Liberty, Indians, Toy Soldiers, Barking Dogs;and 50 others. No experience or tools necessary. Guaranteedcasting forms with complete outfit, at cost. From $3.50 up.We buy goods all year. Cash on delivery. Higher price forfinished goods. Contract orders placed. Send for catalogand information free. The Improved Metal Casting Co..S92 East 145 St.. New York,

InstructionInstruct Yourself for desired Suseessee. Illustrative chart

shows Successiive) Steps. Postpaid 50 cents. 1. I. Morro',Beg 304, Madison SQ. Sta.. N. Y.

Learn Chemistry at Heme. Dr. T. °Tenor Sloane.noted educator and scientific authority, will teach YOU.Our home study correspondence course fit. you to take aposition as chemist. See our ad on page 917 of this issue.Chemical Institute of Ness York, 66 W. Broadway, NewYork City.munemmuolvrms.nemaerro

Insects WantedGet posted-Good prices paid for butterflies, insects. See

Sinclair display advertisement, page 932.

LanguagesWorldRomic System, Masterkey to All Languages. Prim-

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ManufacturingTo order: Metal articles, simple, or complicated machin-

ery. Models. tools, patterns. Experimenting, Parma Engi-neering Works, Brooklyn Station, Cleveland, 0.

Machinery and ToolsConcrete Building Block Machines and Molds. Catalogue

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MiscellaneousFree Complete Price List. Aitken Radio Co.. 504 Su-

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Kodak Hospital. Camera -Exchange. Used Camerassold, exchanged, bought (any condition). Expert CameraRepairing a specialty. Send your broken Camera. Turner.1679 Ave. A, N. Y.

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Get posted-Good prices paid for butterflies, insects. SeeSinclair display advertisement, page 932.

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Motion Picture Business

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Patent AttorneysPatents. Send for free booklet. Highest references. Dom

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Inventors write me about patents. My fess payablemonthly. Booklet free. Frank Fuller. Washington. 1). C.

Herbert limner. Patent Attorney and Moshanleal Engirt124 F Street, Washington, D. C. I report if patent obtain-able and exact cost. Send for circular.

Limey Patent -Sense. "The book the inventor keeps."Free. See page 924,

M. P. Laughlin. Patents. Engineer -Attorney. 98 Eaet91 Street, New York.

H. F. Lowenstein, Registered Patent Attorney, Radio Ex-pert, 825 McLachlen Building, Washington, D. C.

"Inventors' Guide" free on request; gives valuable in-formation and advice for all who have original ideas orimprovements. Frank Ledermann, Registered Attorney andEngineer, 15-E Park Row, New York.

"Inventor's Advisor," the valuable Patentbook with 139mechanical movements and illustrations, sent free upon re-quest. M. I. Labiner, Patent Attorney. 3 Park Row.New York.

Patents, Trademarks, Copyrights procured; all countries;very reasonable; 20 years' experience; booklet Free. H.Sanders, Registered Patent Attorney, 13 Rand McNallyBuilding, Chicago.

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The Patentome is Free. A liberal education in patents.Anderson & Son, attorneys, estb. 1865. 637 F St., N. W..Washington, D. C.

Monroe Miller, Ouray Bldg., Washington, D. C. PatentAttorney; Mechanical, Electrical Expert. Free Blue Bookgives candid advice.

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Inventors-Send for form "Evidence of Conception" to hesigned and witnessed. Form, fee schedule, information free.Lancaster and Allwine, 242 Ouray Bldg., Washington, D. C.

Millions spent annually for ideas! Hundreds now wanted!Patent yours and profit! Write today for free books-tellhow to protect yourself, how to invent. Ideas wanted, howwe help YOU sell, etc. American Industries, Inc., 212Kresge Bldg., Washington, D. C.

Personal150 "Funny" Jazzy Parodies on the Latest Popular Songs.

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Wilson Common -Sense Ear Drums"Little Wireless Phones for the Ears" require nomedicine but effectively replace what is lacking ordefective in the natural ear drums. They are simpledevices, which the wearer easily fits into the earswhere they are invisible. Soft, safe and comfortable.

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BE COMFORTABLEWear the Brooks Appliance, the modernscientific invention which gives rupturesufferers immediate relief. It has noobnoxious springs or pads. AutomaticAir Cushions bind and draw togetherthe broken parts. No salves or plasters.Durable. Cheap. Sent on trial to prove Mr. C. E. Brooksits north. Beware of imitations. Look for trade -mark bear-ing portrait and signature of C. E. Brooks which appears onevery Appliance. None other genuine. Full information andbooklet sent free in plain, sealed envelope.BROOKS APPLIANCE CO., 172 State St.. Marshall. Mich.

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Straightens Shoulders-Increases Pep

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Costs nothing to try itWrite for 30 days free trial offer and free book.

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trl SELF-CONSCIOUS?Embarrassed in company,lacking in self-control? Letme tell you how you can overcome these troubles.VERITA S, Desk 15. 1400 Broadway,New York City

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illustrated in natural colors, etc. Notthe cheap sort. Contains everything one shouldknow both beforeand after marriage to insure health and happiness. Large catalogfree. A. K. SMETANA & COMPANY, OWOSSO, MICH.

Photo plays, Stories, Etc.Wanted. Men and women ambitious to make mow

writing Stories and Photoplays. Send for wonderful FresBook that tells how. Authors' Pros. Dept. 131, Aubone,N. T.

Big money writing photoplays, stories, poems, song.Send for free copy America's greatest magazine for writers.Tells you how to write and sell. Writer's Digest, 637Butler Bldg., Cincinnati, Ohio.

$ $ $ For Ideas. Photoplay Plots Accepted any form; re-vised, criticised, copyrighted, marketed. Advice free. Uni-versal Scenario Corporation, 223 Security Bldg., SantaMonica & Western, Hollywood, California.

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Radio EquipmentGenuine Edison Elements (new) for making "B" Bat-

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Salesmen WantedSpecialty Salesmen! New Ford Money Maker. Kirstin

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$742 Last Month for Beek of Buffalo introducing Iadvertising plan; nothing else like it; every merchant wantsit; easy sales; no deliveries; tie collections; specialty sales-men write quick for offer. National Adv. Service. P.O.Dos 43, La Grange. Ind.

"Salesmen Wanted." Amazing Invention-almost hu-man. The Little Draft-Man-a wonderful labor -saver, auto-matically opens furnace or boiler while owner sleeps. Paysfor itself in fuel saved. Simple, efficient, can be installedby anyone in five minutes. 100 percent profit. Thousandsbeing sold. $25 daily easily made. Act quick, AddressLittle Draft -Sian Co., Dept. C, Grand Rapids, Michigan.

Make $120 Weekly In Spare Time-Sell what the publicwants-long distance radio receiving sets. Two sales weeklypays $120 profits. No big investment, no canvassing.Sharpe of Colorado made $955 in one month. Representa-tives wanted at once. This plan is sweeping the country-write today giving name of your county. Ozarka, 825 Wash-ington Blvd., Chicago.

Short Stories, Manuscripts WantedEarn $25 Weekly Spare Time writing for newspapers.

magazines. Experience unnecessary; details free. PressSyndicate, 566 St. Louis, Mo.

Stories, Poems, Descriptive Articles, Plays, etc. AreWanted for Publication. Monthly cash prize. Submit kiss.or write Literary Bureau, 165. Hannibal, Mo.

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Song Poems WantedWrits the Words for a Sem We compose music. Our

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Poems wanted-Sell your song -verses for cash. SubmitMss. at once, or write New Era Music Co., 145, St. Louis,Mo.@norm. ne

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Stamps -20 Unused. All different. Free. Postage 3c.Mention paper. Quaker Stamp Co., Toledo. Ohio.

California Gold, quarter size, 27c; half -dollar size. 53..Columbian nickel and catalogue. 10c. Neiman Schulz. Box146. Colorado Springs, Colo.

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Telegraphy

Telegraphy-Both Morse and Wireless taught thoroughlyand quickly. Tremendous demand. Big Salaries. Wonder-ful opportunities. Expenses low; chance to earn part, Schoolestablished fifty years. Catalog free. Dodge's Institute,Bane St., Valparaiso, Ind.ilin/1711111,171.1.11111IIIIR11111111111/11111T111111111.111111111111111MIMTITIIITIVIIIII111111/11111111M11111111/13111111tino

TypewritersTypewriters sold on ;laments. Free trial. Porno Com-

pany. Rosedale. Kansas.

All standard makes, $10 up. Fully guaranteed. Freetrial. Write for complete Illustrated lists. NorthwesternExchange, 320 Goethe St., Chicago.

WantedDeteetives Earn Big Money. Work home or travel. Ex-

perience unnecessary. Particulars free. American Detec-tive System, 1974 Broadway, N. Y.

WirelessAttention! 50 Vacuum Tube Hook -Ups. The greatest

collection of Vacuum Tube Circuits ever brought under twosevere at such insignificant cost. These diagrams will befound in the great "Rasco" catalogue which contains rawmaterials and parts in a greater profusion than any ethoscatalogue. lie in stamps or coin will bring the catalogue toYou. Radio Specialty Company, 100 Park Place. New YorkCity.

Boys, don't overlook this! The "Basco" Baby Detector.Greatest detector ever brought out with molded base. Fullyadiustable. See former advertisements in this publicationor our catalogue. Detector with Galena Crystal complete,Ste; the same Detector with Radiocite Crystal, 75c, pre-paid. Send for yours today. Radio Specialty Co., 100 ParkPlace, New York City.

Radio Generators -500 Volt 100 Watt $28.50 each Bat-tery Chargers $12.50-High Speed Motors, Slotor-GeneratorSets all sizes. Motor Specialties Co., Crofton, Penna.

Motors-G. E. HP. $15.00-% HP. $32.50-1 HP.$02.50. Generators 8 volt 10 amp $15. 32 volt 500 watt$30. Other sizes. Low prices. Motor Specialties Co..Crofton, Penna.

BoundVolume No. 9

MAY. 1921-APRIL, 1922CONTAINS

1200 Pages with over 1500 Illustrationsand

Over 700 Articles by the ForemostAmerican and Foreign Writers

We have also a limited amount of the followingBound Volumes of SCIENCE AND INVENTION(Electrical Experimenter) :

Vol. No. 6-May, 1918, to April, 1919.Vol. No. 8-May, 1920, to April, 1921.

Each volume bound in stiff board covered with greenvellum and gold stamped.

Price for Vol. No. 9 $2.25Price for Vol. 6 or 8 2.00

ALL THREE VOLUMES 6.00Send Express Collect.

EXPERIMENTER PUBLISHING CO.53 Park Place, N. Y.

GentlemenEnclosed find $ for which send mbound vol. of S. & I. No. 6 ( ). No. 8 ( )No. 9 ( ), by express collect.

Name

Address

Town State



$200 Miniature Electric Prize ContestTHIS prize contest conductedby PRACT 1CALELEC-TRICS magazine, promises to

be one of the most interesting thathas been staged in recent years.

Here at last is something worthwhile. Not only can you win an at-tractive prize, but you will derive atremendous amount of personal satis-faction from this contest. The illus-tration on this page shows the smallestelectrical motor that has been built.Its dimensions are as follows: 11/64"high ; 19/64" long. It weighs 5.5grains.

This little motor is along the linesof our new contest except that we willnot be quite so hard on the particip-ants. We require miniature electricmodels, the largest dimensions ofwhich must not be more than 3/4".

Any electrical appliance, any electricalapparatus, any radio instrument thatwill be reproduced in a working condi-tion in miniature, is eligible for entryin this contest.

World's Smallest Electric Motoroil

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.2- 11-64" high. When connected to a small flash light bet-a. tery, the motor runs at a very high speed.

$200 (N GOLDFirst PrizeSecond PrizeThird PrizeFourth PrizeFifth PrizeSixth PrizeSeventh Prize .Eighth Prize .Ninth Prize

$755020201010555

The judges will welcome miniaturemodels of the following: Electric bells,switches, all kinds of electric heatingappliances, electric generators, tele-phones, microphones, telephone deskstands, telegraph instruments, any andall radio apparatus, static machines,electric lamps, batteries, rheostats,measuring instruments, fans, trans-formers, in fact any electrical appara-tus or electrical appliance. One of therules of the contest is that the minia-ture models must work. Dummiescannot be entered in this contest. Thebuilders of these miniature modelswill come in for a goodly share of pub-licity as many newspapers and peri-odicals will feature these models.

Full particulars, for entering theminiature models ill this contest, clos-ing date, rules and restrictions, etc.,will be found in full in the Janu-ary issue of PRACTICAL ELEC-TRICS.

The Electrical Magazinefor Everybody

Now Greatly Enlarged

One-third More Text andReading Matter than

Heretoforemnpr,.........,,,olinninrincrrilinumnfrtnrnvil/ITttnIvoririil.......,,l(1111111111111111111111111111.Uti

This Magazine is Edited by

H. GERNSBACKAlso Editor of

Radio Newsand

Science & Invention

100 ArticlesOver 100 Illustrations

For Sale At All News Stands

25c. the Copy$2.50 a Year

Canada and Foreign

$3.00 a Year

411

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PRACTICAL ELECTRICS is probably themost novel magazine of its kind ever con-ceived. It is personally edited by H. Gerns-back, editor of SCIENCE & INVENTION

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The Wonders of RadiumMeasuring Celestial TemperaturesAerial Railroad. by Raymond F. Yates.Analogies and Others, by T. O'Conor Sloane, Ph.D.Electric Timing of Horse Races, by Jacques Boyer, Paris

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Throw Switches

Mounted on compositionblock. Small enough forall radio purposes.14100 Single pole ...1.2514101 Double ThrowSingle Pole

Brass Strip and TubingBrass strip %" wide;1-16" thick; 6" long.11430 Per length....$.1011431 Brass tubing, dia.'/"' 6" long; length .5.15

Threaded Brass RodsSold in 6" lengths only.18032 8-32" thread $.0816032 6-32" thread .4.06

3150

Bakelite 180° CouplerDe Luxe Style

Tubes of natural colorbakellte, w o u n d withgreen silk. Aluminumbracket. Y.," shaft. Pri-mary 13 taps. 180 to 550meters.

35 13150 Coupler $2.45

"Rases" Bezels

Finest Bezel on the mar-ket. Bezel comes entirelynickel plated. Can be usedon %" or 3-16" panel.11700 Basco bezel 1" 3.15J1701 Bezel 1%"diam. 20

Phonodapter

Will fit any phone. Makeyour phonograph a loudtalker. Fits all phono-graphs. Made entirely ofpure soft rubber withbrass tube insert.

11310 Phonodapter...5.40

Alcohol Blow TorchesBest made. Give intensehot flame. Great for finework.18981 5" Torch 3 8518982 3" Torch 5014104 Rosin Core Solder.A non -corrosive solderwith flux inside.18" length

17925

$ 0

(Adjustable) Loud -Speak-er Phone

Has rubber gasket under-neath diaphragm, makingphone fully adjustable.Gives amazing results asloud -talker on 1 and 2stages of amplification.125d25 Speaker with 5 ft.cor $3.70

Rues 180° VariocouplerSilk wire wound on bake-lite tubes. Six taps.Wave length 150 to 600meters. For panel mount-ing. 11." shaft. Yourmoney refunded if it isnot all we claim.13100 Variocoupler pre-paid $1.50

Melotone Loud SpeakerBest popular loud speaker.Fibre horn, heavy metalbase, live foot cord. Nickelgoose neck. Greatest tuned(adjustable) talker. Hornlength 11%"; bell 6%";total height 0".1255 Melotone Speak-er $4.90

. Skinderviken Button .

Famous Micro -Phone forTransmitters. Sold allover for $1. This is thegenuine article. No imi-tation. Smallest and most

en sitiv e microphonemade.19595 Microphone ..5.75

J3500

Soft Rubber Ear Cap

At last) Ear caps thatwill relieve headaches,earaches, and undue pres-sure on the ears. Fit allreceivers.

13500 Ear caps; pair 5.50

Dileetryte PanelsHighest dielectric strengthas per Bureau of Stand-ards.17100 7x10x3-16" ..$ .9017120 7x12x3-16" .. 1.0517140 7x1413-16" 1.2017180 7x18x3-16" .. 1.6017210 7x21x3-16" .. 1.8517246 7x24x3-16" 2.10

Loop AerialMade entirely of well sea-soned hard wood. Com-plete with all parts andbase. Total height ofloop 36". Can be put to-gether by anyone in lessthan 5 minutes.12600 Two ft.- loop aerial.con:valets $1.15

"Rase*" Switch PointsNickeled and polished.1301, 3/4,"x/,", 6/32",doz. 181304, 1/4" dia., 1/4" thick;6/32", doz 181305, 1/4" dia., 3/16"thick, 4/16", doz. ... 18J375, IA" long, 4/36"with nut, doz 18

Series Parallel Switch

Quick change from onecircuit to another. Blackcomposition knob, nickle

dPiuslated 11/4"

fittings. Blade ra-.

12950 Series parallelswitch 25

Short WaveRegenerative

Receiver1-0710 Mahogany Cabinet

7":10" $2.601-J7100 Dielectryte Panel

7"x10" .90l-13150 DeLuxe Variocoupler 2.451-ses43 43 Plate Condenser 1.602-13075 3" Dials .501-1200 Switch Lever .251-Doz. 1305 Switch Points ' .18

2-1375 Switch Stops .04l-16500 Vacuum Tube Socket .351-15060 Grid -Leak Condenser .301-14311 30 ohm Rheostat .651-11000 Double Circuit Jack .658-1201 Binding Posts .808-16000-8, Binding Post

Name Plates :2424 Ft. 16400 Bus Bar Wire .60Blue Prints and directions for

assembling .50

Total $12.61

Our Price $12.00

Reinartz Circuit1-1710 Mahogany Cabinet

7"s10" $2.601-17100 Dilectryte Panel

7"x 10"x3 -16" .901-12660 Reinartz Inductance

(225 to 600 meters) 1.901-16500 Vacuum Tube Socket .351-14311 30 ohm Rheostat .652-12121 21 Plate Variable

Condensers 2.501-15059. Grid Leak Conden-

ser ' .308-1201 Basco Binding Posts .802 Doz. J305 Switch Points .36

3-1200 Basco Switch Levers .752-13075 3" Dials .502-11450 Vernier Attach-

ments .6024 Ft. 16400 Bus Bar Wire .601-11000 Double Circuit Jack .651-01003 Basco Plug .558-16003 Binding Post Name

Plates .241-11430 Brass Strip

6"x%"x1-16" .101-Consrnd Assembling

Pattern .50

Our Price '$1411ig

2 Stage Amplifier1-17 1 0 Mahogany Cabinet ..$2.601-17100 Dilectryte Panel .. .902-11100 A.F. Transformers. 4.002-11000 Double Circuit Jacks 1.301-11003 Basco Plug .552-16500 Tube Sockets .702-14311 30 ohm Rheostats 1.3010-16060 Post Name Plates .3010-1201 Basco Binding Posts 1.0010 Int.-16400 Bus Bar Wire .75Blue Prints and directions .50'

Tntal. $10 90

Our Price $13.50

RADIO SPECIALTY CO., 100 Park Place, New York CityFactories: Brooklyn, N. Y. Elkridge, Md.

This advertisement copyright 1923 by R. S. Co., N. T.


Let These Guides

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FtC


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Name

street

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Dept. 14 -AA, Wrtehington, D. C.


To Prove That I Can Fit - World Radio History

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Transcript of To Prove That I Can Fit - World Radio History