october - World Radio History

OCTOBER 25 CENTS :

cience ancinvention

AerialFire Fighters

When FateFooled Houdini

By Dunninger

Who Will Build the Fastest Ship?,By James C. Young

via ThNivistiGi4kaEtsIV, ligley Saving

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October, 1929 Science and Invention 481

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This Issue Contains These UP-TO-THE-MINUTEArticles by WELL-KNOWN Authors

General ScienceWhat Price Ship Speed ? 484Editorial 488Aerial Fire Fighters 490Inside the Graf Zeppelin 491New Hudson River Bridge 492Engineering Taught by Movies 492Who Will Build the Fastest Ship.' 494

By James C. YoungScientific Progress 496New Thrills by Science in Sports 498Can You Solve These Scientific Puzzles ? 500

By Ernest K. ChapinDo You Resemble the Typical American Genius ? 501Would You Believe It ? 502Noah's Ark Lives Again for the Movies 503

By Edwin SchallertWhen Fate Fooled Houdini 504

By DunningerTime and Labor Savers 506Coal Miner's Job Safer Than Yours 1 507

By Alvin F. HarlowPlaying With Death 508

By N. A. FoazrimDust ! 510Light Controls Machine. 511Rotary Auto Engine 511Making Sound Behave ! 512

QuinceyMagic-A Monthly Feature 514

By DunningerGermany's 120 -Passenger, Twelve-Engined, Trans-

oceanic Air Liner 51525,000 Miles Without Landing ! 516A Merry -Go -Round Demonstrates Einstein Theory 517

By Dr. Donald. H: MenzelGrow New Plants Without Any Seeds 518

By Dr. Ernest BadeWhat. Our Readers Think 532Scientific Humor 538Latest Patents. 539The Oracle. 540Financial Information 547

By Alfred 111. Caddell

AviationAerial Fire Fighters 490Inside the Graf Zeppelin 491Germany's 120 -Passenger. Twelve-Engined, Trans-

oceanic Air Liner 51525,000, Miles Without Landing ! 516A New German Glider 525

Chemistry and ElectricityDust ! 510Light Controls Machine 511Wrinkles and Recipes 530

Home MoviesEngineering Taught by Movies 492Movie Projector for Your Library 511"Home Movies"-A Monthly Department 521

By Don Bennett

AutomotiveRotary Auto Engine 511Motor Hints 520

By George A. Luers

RadioAttractive Dynamic Speaker Cabinet 534

By A. BrantsSoldering Iron Control for Delicate Work 534New Nine -Tube A. C. Receiver 535New Radio Devices 536Radio Oracle. 537

How to Make ItHow to Have Talking MoviesHome Wood Turning Provides Artistic Lamps and

Candlesticks 523Making an Air Lift Pump 524How to Make It Department 526Hints for the Home Workshop 528Wrinkles and Recipes 530

NEXT MONTHSolving Traffic Problems From the Air

Several ingenious schemes will be described wherebyboth town and country traffic problems may be readilysolved by aerial observation.

With the Aviation InventorsYou will be surprised at just what the patent office

records reveal when it comes to airplane and dirigibleinventions.

A Flying Hangar for AirplanesTraffic in the air is growing very rapidly and even

522

now our military authorities are experimenting with aflying hangar for planes.

Should I Buy an Oil Burner?An informative illustrated article on oil burners for

the home, written by an expert.

Are All Mediums Fakes?The author of a very interesting article in the next

issue of this journal tells of the many mediums he in-vestigated and their clever trickery.

VOL. XVII. \Vhole Number 198 Oct., 1929, Number 6

SCIENCE AND INVENTION. Publishedmonthly by Experimenter Publications, Inc., at184-10 Jamaica Ave., Jamaica, N. Y. En-tered as second class matter, at the Post Officeat Jamaica, N. Y., under the Act of March 3,

1879. Title registered at the U. S. Patent Office.Copyright, 1929, by Experimenter Publications,Inc. The contents of this magazine ,must not bereproduced without giving full credit to the pub-lication.

Subscriptions: $2.50 per year in U. S. and

possessions; Canada and foreign countries, $3.00a year. Mackinnon -Fly Publications. Experi-menter Publications, Inc. Novel Magazines Corp.Executive and Editorial Offices, 381 Fourth Ave-nue, New York City, N. Y.

482


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484 Science and Invention October, 1929

What Price Ship Speed ?

VECPET glimpse into tle ermine room of the "Ile deFrance,' one of our fastest ard mos! 1r:curious of modern

ocean This photo fives some Urn of the complexand mtssive machinery rewiirea to profref a large ship ofthis type across the ocean. Oil pie; is birmed in the boilersof this :hip. Steam turb_nez conc:ert the erergy in the steamto rota -y mechanical motion, winch is .rapsinitted in turn tothe preteners through steed reerection g7ars. The "Ile deFrance' develops 55,000 horse -power. Az the ship's speedis incretsed, the power required to efric-ie leer increases muchfaster an 0.-oportion, so that there is an economic limir tothe speed a! which an oeeaz gre,hot.ne trek.; be forced. The"Brem.rn" cutstripped ad other vcecn liners, but to gain afew m 'es more in speea per hoer the er*ine power had to

be raised to 120,003 f-12.


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Clarence Heffelfinger,Temple, Penna.

'SOO a month"When I enrolled with the N. R. I., I

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Richard Butler, 3535 Sheffield St.,Philadelphia, Pa.

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922 Guadalupe St.,Frank M. Jones,San Angelo, Tex.

READ what BigMoneymy men make in RADIO

$350, $450, $500 a month. That's making real money.What business other than Radio offers such oppor-tunities after six to twelve months training? Nonethat I know of. More proof-last year electricians,farmers, mechanics, clerks, railroad men, book-keepers, preachers, doctors, and men from 78 othertrades and professions enrolled with me .o preparefor the Radio field.

Big Growth Making Many Big JobsAWoNDERFUL business, you will say, to make

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Salaries Up To $250 a WeekWHY go along at $25, $30, $35 a week when the

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VOLUME XVIIWHOLE NO. 198

\` SARTHUR H. LYNCH, Editorial Director.

H. WINFIELD SECOR, E.E., Managing Editor.JOSEPH H. KRAUS, Field Editor.T. O'CONOR SLOANE, Ph.D., Associate Editor.

OCTOBER, 1929NUMBER 6

AUGUSTUS POST, Aviation Editor.ALFRED M. CADDELL, Financial Editor.WILLIAM F. CROSBY, Marine Editor.

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

TRANSATLANTIC TRAVEL

RECORDS for crossing the Atlantic are being broken almost asimpressively as flight endurance records. The following listindicates the actual manner in which this has been brought about

since Christopher Columbus blazed the trail.

1492-Columbus sailed from Palos, Spain, to the Bahamas in 71 days.1819-The Savannah, an American -built steamer of 350 tons, crossed

from Savannah to Liverpool in 26 days, being the first steamer tomake the Atlantic passage.

1838-The Great Western crossed from Bristol, England, to New Yorkin 13%, days. Subsequently she made a record of 10 days, 10hours and 15 minutes.

1866-The Scotia made the run between New York and Queenstownin 8 days, 2 hours and 48 minutes.

1882-The Alaska, New York -Queenstown, 6 days, 18 hours, 37 minutes.1891-The Majestic, New York -Queenstown, 5 days, 18 hours, 8 minutes.1910-The Mauretania, New York -Queenstown, 4 days, 10 hours, 41

minutes.1927-Col. Lindbergh flew 3,600 miles from New York to Paris in

33 hours, 29 minutes, 30 seconds.September, 1928-The Mauretania crossed from Cherbourg to New

York in 5 days, 2 hours and 34 minutes, beating her record ofAugust, 1924, of 5 days, 3 hours and 20 minutes.

1928-The airplane Bremen crossed westward from Ireland to northeastcoast of Province of Quebec in 36V, hours.

1929-The steamship Bremen crossed from Cherbourg to New York in4 days, 17 hours and 42 minutes.

1929 --The Graf Zeppelin flew from Lakehurst to Friedrichshafen in55% hours (4,200 miles).

In the conquering of the Atlantic, and the speeding up of communi-cation between this country and Continental Europe, a number ofromantic characters stand out in great relief. Possibly the charactermost in the public eye in this connection at the present moment is Capt.Hugo Eckener, who, if all goes well with him, will be just returningto Lakehurst as the magazine carrying this editorial reaches the news-stands.

It is, perhaps, the natural working of what many of us consider tobe an unjust fate that much of the hardship and study and planningfor a trip such as Commander Eckener's is borne by the ground crew.Walter Hinton, who, by the way, made the first transatlantic aircrossing in the airplane NC -4, is responsible for the statement that "forevery job in the air forty people are required on land." From thisstatement we get some idea of the immensity of the work entailed inpreparation for a transatlantic airplane flight, to say nothing of thework and planning necessary for the flight of a dirigible such as theGraf Zeppelin or the two English air Leviathans which will soonvisit this country. Much of the glamour of the conquest is centeredupon the captains and the pilots under whose command these wonder-ful results are accomplished, and we cannot refrain in passing fromsaluting the men ashore who stand behind every one of these success-ful undertakings.

Editorial Director488


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490 Science, and Invention October, 1929

A

Aerial Fire Fighters

t

pl6 It

2: 1

The illustration above and at right showshow the aerial fire -fighting planes wouldattack a skyscraper fire. The plane wouldfly to the scene of the conflagration and landon the roof of the nearest building. Thesuction hose will be attached to the building'sstandpipe and one or more hoses attached tothe delivery pipe of the pump, the pump acting as a "booster" andserving to throw streams of water several hundred feet beyond

the range ordinarily possible.

0 UR front cover and the accompanying illustrationalso illustrate the very latest idea for fighting fireswith the aid of airplanes. The airplane shown in

the accompanying picture is a' special new form of plane,known as the autogiro. The outstanding feature of this newtype of aircraft is that it can ascend or descend almost verti-cally on the order of a helicopter. One of our leading fire-fighting experts, a member of the New York City Fire De-partment, recently declared that the city is on the verge ofadopting the airplane as a part of its regular fire -fightingequipment.

The accompanying picture shows how the autogiro formof plane could be arranged to carry hose, as well as a firepump and accommodations for several firemen. A specialclutch would permit the airplane engine to be connected withthe water pump, this pump taking water from a standpipe

How Airplanes Will Increase Speed and Effi-ciency in the Oper-ation of Fire

Departments

By John Croller

terminating at the building roof.Where insufficient pressure of waterwas available to fight fires in tall build-ings in the vicinity, the pump on theairplane would act as a booster andenable the firemen to direct streams ofwater into much higher buildings inthe vicinity. Another distinct advan-tage of the airplane as one of theimportant links in our modern fire-fighting equipment lies in its greatspeed. Imagine how much faster afleet of fire -fighting planes could travelseveral miles to a large conflagration

compared to a number of automobile fire engines makingtheir way through the crowded streets of a large city likeNew York or Chicago. These fire -fighting planes wouldcarry, in addition to hose and pump, a goodly number ofhand -operated portable fire extinguishers, axes, scaling lad-ders and other equipment which readily permits its crew offiremen to put out any ordinary blaze. The cost of thesefire -fighting planes would be quite reasonable, consideringthe great advantage of speed with which these planes couldtravel to a fire. These planes can also land on the water. ifthey are designed as amphibians, and in this capacity theywill prove invaluable.

In fact it would not be unreasonable to assume that in tento fifteen years from now a major part of our fire -fightingequipment may have "sprouted wings." As our cities keepexpanding and our suburban sections multiplying, the prin-cipal desideratum will be speed, and the airplane seems tobe the best answer to that problem. For the small town fire-fighting equipment, the airplane will soon prove indispensable.


10SLEEPING

CABINS

OBSERVATION.PLATFORM

SECOND CORRID0'12-1- 44'

PASSENGER CABIN

PILOTS BRIDGE BALLASTLOWER

17 LIFTING" GAS CELLS

iilowllCORRIDOR SHIPS STORES.

FUEL TANKS r

=IT -1'-2 FUEL

GAS SAGS

INSIDE THE

Graf ZeppelinTHE sectional view of the Graf Zeppelin,

shown herewith, gives some idea of the corn-plicated internal structure of this large

"grown-up" balloon, which carries two kinds of gas,hydrogen for lifting her huge bulk and Blau gas asfuel for her five Maybach engines. Gasoline is alsocarried as auxiliary fuel for the engines, but onlya small quantity of this fuel is carried. A simplevalve enables the engineers to instantly switch theengines from Blau gas fuel to gasoline, and viceversa. The Blau gas is carried in twelve bagsalong the bottom of the frame, just under the hydro-gen "lifting" cells or bags. The Graf Zeppelincarried 22 passengers and a crew of 40 men, includ-ing three pilots and three navigators, when she leftLakehurst, August 8.

ENGINE 'EGGS. OBSERVATION WIN

Unusual "bottom" view of modern dirigible, showingHow the bottom of a

modern dirigible such as theGraf Zeppelin looks is illus-trated above ; note trap-door for lowering ropes andalso the observation win-dows.

Graf Zep compared to Wool-worth Building.

rrii7nrarM.gW

MOORINGRAIL

CONTROL CABIN

windows.

CORRIDORSALON

Sectional new of the Graf Zeppelin.

RADIOCABIN NAVIGATION

ROOMPILOTROOM

ELECTRICKITCHEN

LIGHTGENERATOR

Where the officers and passengers live.

GASCONTROL

The passenger cabins. dining salon, radioroom as %yell as the "bridge" are shown above.In stormy weather the commanding officerspends many hours on constant watch, togetherwith his officers, at this important key position

on the dirigible,where mechani-cal and electri-cal means areprovided foropening andclosing gasvalves, ballastdumps, etc.

23110.1422¢I.71".".

411;

Note second corridor in Graf Zeppelin, for inspection purposes.

To inspect the 17 "liftinggas" cells, also the 12 fuel gasbags. the designers of theGraf provided a lower and asecond corridor or catwalk.

If you saw the Graf Zep-pelin stood up on its tailalongside the WoolworthBuilding, it would reachnearly up to the dome of thatfamous edifice. Imagine thebending and twisting stressesin a "balloon" of this size.

-------------------------------------------- -4 --LOS ANGELES - 660 FT LONG. x00 Ft DIA.

(ENGLISH)- 730 130 - GRAF ZEPPELIN - 776 98--- ------------------------

Los Angeles, R-100 and Graf Zeppelin compared as to size.

Round -the -world mapat right shows path ofGraf Zeppelin on her25,000 -mile air journey,on which she will makestops only at Fried-richshafen, Tokio. LosAngeles, and Lakehurst.

LANDING of a large dirigible such as the Los Ange-les or the Graf Zeppelin is carried out as shown

below. The airship steers downward under her ownengine power and drops ropes down. When low enough,the ground crew grabs the ropes and pulls her down lowenough to anchor on a mast, or still lower, when she is"walked" into a hangar.Bringing down a large dirigible-ground crew grabs ropes

and walks Zep to mast. --------

----------------- " ----

I I.

------------------- ------

Grals round -the -world route.

---

-------------


home -study engineering student operating 16 mm. motion-picture projector and some of the "lesson" reels. He reads

the lesson and then projects the images on the screen.

Comparison of the Brooklyn Bridge with the newly proposed Iludson River Bridge at 57th Street, New York City.

New HUDSONNOTHER Hud-

son RiverBridge re-

cently proposed bythe North RiverBridge Company, inassociation with theBaltimore and OhioRailroad, is estima-ted to cost $180,000,-000 and would joinNew York City at57th St., with theNew Jersey shoreacross the Hudson.This gigantic proj-ect long contem-plated is intended to relieve the severe traffic situation acrossthe Hudson River, and also to afford the Baltimore and Ohioand other railroads direct access to the heart of the greatmetropolis. This huge bridge is designed to have two largedecks, one above the other. The upper deck would carrytwenty lanes of vehicles of all kinds, including trolleys, be-tween two promenades for pedestrians on either side. The

RIVER BridgeTo Carry Vehicles and Trains

N o t e the greaternumber of trainsand vehicles to becarried by new

bridge. BROOKLYN BRIDGE

NEW BRIDGE

Upper deck carries20 lanes of vehicles,lower deck 12 rail-

road tracks.

lower deck wouldprovide space fortwelve railway tracksand on either sideof these tracks therewould be space fortwo moving plat-forms for local pas-senger traffic. Atabout Tenth Ave.and 57th St. inManhattan it is pro-posed to erect a newunion railroad sta-tion at the bridgeterminal. The bridgedesign involves the

suspension principle and calls for a single river span of3240 feet, with two side spans of 1590 feet each. The totallength between abutments would be 7210 feet. The bridgedesign has been changed so as to give a clearance of 175feet above the river for boat clearance, but the War De-partment engineers are asking a clearance of 200 feet, en-tailing considerably greater cost (Continued on page 542)

Engineering Taught by MoviesHERE correspondence courses in engi-neering, not to mention resident courses,are concerned, there is probably no quicker

method than that utilizing motion pictures, forquickly unfolding to the student the elementary ac-tion taking place as a current flows through acircuit for example. To those who have neverseen an animated movie, such as those produced byBray and used to a large extent in army and navy

schools during the WorldWar, it is not perhaps ap-parent at first why themotion picture should be soastonishingly useful in de-picting the action of elec-trical and mechanical ap-paratus. Several scenesfrom one of the many"lesson" reels supplied tostudents by the NationalSchool of Visual Educationare reproduced in the pic-ture at the right. The twoupper pictures show thecircuits of an electric motor,while the two lower pic-tures show the action of a(Continued on page 562)


Artificial LightningBroadcast by WGY

CRASHES of artificial thunder, produced by the new 5,000,000-volt lightning generator of the high -voltage laboratory of theGeneral Electric Company, at Pittsfield, Massachusetts, were

heard recently during a talk on lightning delivered by F. W. Peek,Jr., consulting engineer of the General Electric Company, from sta-tion WGY. The photograph shows one of the high -voltage sparksjumping a needle -gap in the laboratory. In the inset are KolinHager, WGY announcer ( left), and F. W. Peek, Jr. A spark thislong produces a crash very similar to real thunder.

AltimeterUses Radio

EchoANEW type of al-

timeter, developedby Dr. E. F. Alexan-derson, uses a reflectedradio impulse to show al-titude. The distance ofan aeroplane f r o in theground is indicated bycolored lights. Green,yellow and red lightsgive warnings at 250, 100and 50 -feet altitudes.

Girder "Aerial" forHOW tci receive radio programs in

steel -frame buildings is a problemthat has held the attention of radio engi-neers for several years. Dr. F. L. R.Satterlee, retired X-ray experimenter,of New York, and Louis Kalosky, aHungarian engineer, have succeeded inworking out a system that uses the steelskeletons of such structures; retrans-mitting the program received over thesteel so that it can be picked up by setsin any part of any given building. At

The master set installed at theLincoln, which receives the radio programsand retransmits them via the steel -girderframework of the hotel. The guests of thehostelry have the choice of six programs.

Hotel

Broadcasting "artificial lightning" from station "WGY."

Inventors of building frame antenna sys-tem, with one of the four -tube receiving

sets.

the Hotel Lincoln, New York. wherethe system is in successful operation,six programs are received on six sets.All of them are transmitted via the steelframework of the hotel, giving to theguests the choice of six programs totune in on. In the tests made thus farat the Lincoln there has been no crowd-ing or heterodyning, and all of the re-transmitted programs are free of static.The sets used at the hotel are all four -tube, all-electrics, which operate fromthe house current. Attempts to pick upthe programs in other nearby steelbuildings were unsuccessful.

A Mystic RadioOPEN one connection to the loud

speaker of a radio set and bringout two leads as shown. The speakerwill operate when the leaf of the plant

TOSET

TO HANDBEHIND BACK

is grasped, if the set is working. Ondrawing the thumb and forefinger upthe plant leaf, the sound gets softerand softer ; and as the fingers are run tothe tip of the leaf, the music ceases, tothe astonishment of the spectators.-R. B. Wailes.

41)4 Science and Invention October, 1929

Who Will Build the FASTEST

"Ile Flan ,," of tle f shirr of today.

The fourgiantscrewsthat propelthe "Ile deFrance"across theAtlantic inlast time.Note themen in

A hove we seet h e "controlbridge" of the"lle de France."Note the loudspeaking t el e -phones, steeringwheel, compass,and other instru-ments. auto-matic oceandepth recorderis located here;also radio com-pass, etc. Left:main diningroom with "ar-tificial sunlight."

B y James

THE great ocean race is on again. Cherbourg break-water soon .will lie within four days of Ambrose light,off the port of New York. After fifteen years' delay,the world's big maritime nations at last have come

to the starting line for the race suspended in 1914.The last arrival in the Atlantic race turned into Ambrose

Channel when the Bremen crossed the finish line, fourclays, seventeen hours, forty-two minutes from Cherbourg,a matter of 27.83 knots for the voyage. Or eight minutes,port of nine hour, lager than the Atlantic ever had beencrossed before. 1)(m.n came the "blue pennant" of theCunarder Mauretania after twenty-two years as mistress ofthe seas. It was justice, in a way, because the Mauretaniatook her crown from a once famous German ship, theKronprinzessin Cecile.

Any one looking at the Bremen steam up New Yorkharbor could not doubt that her coming marked a period inocean navigation-in world transportation by any medium.Even a Zeppelin cannot be expected to make a better averagespeed. The passing of supremacy from the steamship tothe air has been definitely delayed. When no more than fourshort days-four revolutions of the globe-lie between thetwo hemispheres, it seems unlikely that we shall desert theleviathans of the deep for the motored monsters of the air.

And it well may come to pass that an American ship shallbe the first to cross the Atlantic in four days flat. TheodoreE. Ferris, designer of fast yachts, steamships and almostevery other sort of craft that floats, believes a speed of thirtyknots or better is now practicable. That would easily bring

The fastest ships on the seven seas in another two years maynew U. S. Lines proposed vessels, the appearance of which is

in the above naval architect's drawing.

be theshown

Science and InventionOctober, 1929 495

SHIP?C. Young

Hoch "Bremen!" the new Queen, of the Seas. This fast German ship broke all recordsin crossing the Atlantic, completing the time between Cherbourg and New York in4 days, 17 hours, and 42 mimutes. She develops 120,000 H. P., about twice that of the

"Leviathan." The "Bremen" is 938 feet long and displaces 46,500 tons.

Cherbourg breakwater within four days of Ambrose light.Mr. Ferris is engaged in planning the two new ships of theUnited States Lines, which, he says, "will be the biggest andfastest ships on the Atlantic."

The Bremen was a revelation to shipping men who havewatched the recent generations of ships pass throughAmbrose Channel, for some decades the highway of theworld. At the first glimpse she was seen to be a differentkind of ship from any that had crossed the bar of New York.One man compared her to that noted piece of Greek sculp-ture, the galley of Samothrace. where the figure on the howleans forward, literally drawing the ship behind. And theBremen seemed to "lean" to her task.

In fact, she is a ship of the "leanest" lines that has come into NewYork harbor for many a day. It is plain that the German designersprofited from a study of their submarine experience and the scienceof aeronautics. The Bremen embraces something both of the U-boatand of the airplane. Looking at her under way, the impression is notunlike that felt in watching an airplane rise. She "leans" into thewind, her long hull flattened at the bow until the size of the ship ishardly realized by one who watches her.

This flattening process has touched every detail of the Bremen out-side. Her forward superstructure, where the deck house rises fromthe hull, slopes gently backward, as though human hands had mouldedit from clay. Then the two big stacks, fifty feet long and twenty feetwide, have been flattened as well. The hull widens to a ninety -eight -foot beam, disguised by the lean design. It tapers aft to a stern aslean-almost-as her nose. The 938 feet of the Bremen make her thesecond largest ship in the world. (Continued on page 544)

The new proposed U. S. Lines ships are expected to be about 1,000 feetlong, exceeding the "Bremen," and their size of 55,000 tons is also

greater than the "Bremen's."

"Direction panels"on every deck ofthe "Bremen" en-able the passengersto find out how toreach any officer orpart of the ship, bysimply pushing alabeled button. Im-mediately the routeto the desired spot

is illuminated.

MOTOR -OPERATEDCRANE

TAKING -OFF

"Bremen,"first shipto sportan electric

sign.

The"Bremen's"

airplanecatapult.

114

rT


;-4

-1:1117

New Bridge Over Colorado RiverTHE new bridge over the Marble Canyon in Arizona

does away with the last of the old frontier. This bridgepresents the only automobile bridge across the Colo-

rado River, between Needles and Green River, and is located

The illustrationabove gives onea good idea ofthe bridge andthe topographyof the surround-

ing land.

=r0=0:41AR/ Z ONAi

~ran !

The map atthe leftshows loca-tion of thenew LeesFerry Bridge.

a few miles west of Lees Ferry and some 130 miles due northof Flagstaff, Arizona. At this point there was a ferry whichwas one of the few crossings of the Colorado River whenthe first settlers made transcontinental pilgrimages. Thebridge itself has a span of 616 feet and dwarfs the LosAngeles City Hall, which is shown compared with it.

The road to the bridge leads from Flagstaff, Cameron andother points in Arizona and on the western side to ZionNational Park and other points in Utah. A gorgeous view ofthe Marble Canyon of the Colorado River can be obtainedfrom this structure. How many stop to consider that, withthe constantly increasing strides in aviation. such bridgesmay in time become interesting landmarks only, even as didthe ferry at this point. A plane needs no bridges, no high-ways, and its road is kept in constant repair by nature itself.

ScientificThis Auto Will Sell for $200

THE tiny carhere shown is

the invention ofJames V. Martinof Garden City,L. I. There is nochassis, frame orsprings. Eachwheel is inde-pendently mount-ed and shock cordused in the placeof springs. It

The new poorman's car and howit compares withan average touringcar; its ridingqualities are saidto be even better.

weighs 600 lbs., does 50 miles on a gallon and is shipped ina weatherproof packing case with a hinged door. The caseserves as a garage, if the owner does not want to build one.

Moon Rocket Misses Moon

PROF. ROBERT H. GODDARDof Clark University, located at

Worcester, Mass., is continuing his ex-periments with his "moon rocket." Thisrocket was intended originally to ex-plore the higher atmospheres beyondthose heights already reached by man.The structure shown at the right wasbuilt for directing the trial flight. Aliquid explosive was used, but instead ofthe explosions expending their forcegradually, as was intended, the entirerocket exploded when it was but a shortdistance beyond the guide. If you areinterested in knowing how rockets reachthe higher altitudes where there is noair on which the gas can react, see theOracle Department in this issue.

This Machine Tests Fighters' HeartsHARRY FORBES,

the leading con-tender for the feath-erweight title, isshown here havinghis heart tested byhe new portable

electrocardiograph.This is the first timethe machine has beenintroduced into theprize ring for thispurpose.

1


AA

ProgressSixty -Mile -an -Hour Tank

ATHREE-MAN,armored combat

tank, capable ofmaking 42.55 milesper hour over roughplowed fields andsand dunes, whenequipped with cater-pillars as the photoshows, and whichcan make 69.23 mileswith caterpillars re-moved, amazed both

New "sixty -mile -an -hour" tank.

army and civilianofficials who witnessed the official armytest. This high-speed tank is equippedwith an anti-aircraft gun and presentsbut a small target to enemy aircraft.

"Look Pleasant" When You Turnin the Fire -Alarm

MO discourage false alarms, a newI fire -alarm system has been installed

which not only registers the alarm, buttakes a motion -picture of the individualwho turns in the fire -alarm. Thr pho-

The fire -alarm systemand the photos it takes.

tographs here show the apparatus itselfand also a reproduction of a portion ofthe motion -picture strip showing MayorWalker of New York turning in analarm at the fire -box.

Showing how the floodlights are arranged in

the building.

A Life -Sized Cave Man

THE first authoritative life-sized re-construction ever made of a cave

man, his family and his cave has justbeen completed at the Field Museum ofNatural History in Chicago. This is

one of the earliest types of prehistoricman who lived in western Europe some50.000 years ago and more. On the leftis a photograph of a hungry boy aboutl2' years of age of this Neanderthaltype.

Another "Death" Cage

HERE is a stunt being demonstratedin Berlin which is a great sensa-

tion. It shows the thrilling chase be-tween a lion and a motorcyclist in alarge ball -like wire cage.

Floodlighting

Dome ofBuilding from

the Inside

10 "I NI 0010 IV ll If

T N order to make the light "bend"around a curved surface so as to il-

luminate the top of the dome, it wasdecided to flood light the 36 -foot domeof the new Williamsburgh SavingsBank in Brooklyn from the inside. Thetop is not glass, but is built up of hori-zontal louvers. The gilded surfaces ofthese louvers are then illuminated fromthe inside by varicolored lights.

Foods You Can't Eat

THESE lamb chops, steaks, rolls andbread are made for display purposes.

The inside is sawdust and plaster ofParis; the outside wax, carefully col-ored and treated.


THIS MOTOR -D RI I" E N SKIB0.4 RDis an aquaplane, fittedwith an outboard motorpowerful en ough todrive it at a high rateof speed. Riding it isvery exciting and it re-quires great skill andmay cause many a spill.

14111111011,.

"ELECTRIC SUNLIGHT"-Beath wavesand sea breezes are the features of thisindoor Lido, located underground in Paris.

A NIP rOrn1Pc vsN,

t 6111,41..

"BARREL -ROLL" a la motorboat at Win-terhaven, Florida. The pilot now closes

the top and-see right.

THE PLEASUREFLOAT shownabove combines ametal floatingdock with slipsfor the entranceof motor -boats, aplatform foraccommodation ofguests and diving

boards.

New THRILLSby Science in Sport

Novelties That Give Us a KeenerAppreciation of the Playful Side

of Life

By Henry Wells

INVENTORS are doing their partto help us enjoy ourselves in therealm of sports and to entertain us

by various amusement apparatus whichmore often than not startle us by theirsheer novelty of effect. Of course, onewould naturally expect that most of

these novelties would take on a watery aspect, if we may bepermitted the pun. The outboard motor lends itself admir-ably to two new uses. We find the sponsors for these sportsat opposite ends of the continent. The first was tried out inLos Angeles recently and is a special skiboard driven bysuch an outboard motor, which is steered by tipping theboard slightly. A little too much tip and the riders get aducking. We have as yet been unable to learn what happensto the engine when this takes place. At Winterhaven, Flor-ida, an inventor used the outboard motor for operating anenclosed vessel with which he thrilled the crowds on theshore by making it perform a series of barrel rolls. A littlemore mild is the new-fangled surf -board, invented byE. Wright, of Los Angeles, California. This device is illus-trated on these pages. As can be seen, the surf -board has asedan top, with suitable openings in the sides of the hull,through which the swimmer i who lies flat on his stomach)can put his hands and, by going through the regular swim-ming motion, can propel himself out into the ocean, wherehe turns around and rides back on the waves. While speak-ing of water sports, we must not forget the one invented bya police captain at Avalon, in the beautiful Catalina Islands.This consists of a 14 -foot ball, which is inflated and whichhas been fitted with numerous short pieces of rope. Half ofthe ball is painted red, the other half is green. The objectof the game is for the competing teams to get their colorabove the water. The thrills are many and the duckings arefrequent, as one side suddenly decides to tug on the ropes oras quickly release them, plunging the opposing team belowthe surface.

It is not always possible for everybody to indulge inwater sports throughout the year,and for this purpose our modernindoor swimming pools come to therelief of the aquatic enthusiast.But where in this country can we

Shifting hisweight inside,the "BabyGrapefruit"causes it tomake a complete

roll.

A close-up of the inventor and his craft.


ROLLING WATER SPHERE de-fies you to preserve your balanceon its top, while others are at-

tempting to upset you.

GLOBE OF CHANCE isthis huge steel sphere, at theright, 57 feet in circumfer-ence, used by E. E. Phill-more, who drives his motor-cycle around the interior in

all kinds of loops.

find a pool as unique as the subterranean Lido in Paris.Here is a swimming pool which reproduces in miniature mostof the attractions of the famous Adriatic resort. It liesunder the beautiful arcade which is one of the most attrac-tive shopping centers in the Champs Rlysees. Here wefind a swimming pool with artificial sand, artificial sun-light which burns until 3 A. M.; a restaurant, a beautyparlor to relieve the ravages of the "sun," and the "winds,"provided by fans suitably arranged and concealed. And hereand there parasols of bright colors dot the undergroundbeach.

But we must not think that the inventors in this countryalone are making special efforts to amuse the populace. InBerlin, Germany, an airplane novelty merry-go-round wasrecently originated and is now becoming very popular. Theground pilots cause the machine to rotate at a high rate ofspeed by raising and lowering the wings. There is no otherform of drive. However, in order to get a certain co-ordi-nation necessary for maximum speed, there is a crankshaftarrangement at the center connected with the fan blades.This forces a regularity of the fan movement and necessi-tates a certain degree of co-operation.

Those who are inclined to partake of greater thrills willfind the invention of Gustave Melling, of Flushing, NewYork, of unique interest. We all know how roller coastersoperate. Well, this is something slightly different from aroller coaster, in that the body of each car is so mounted onthe chassis that it can swing from side to side and also isfree to move up and down. Due to offsets in the road, thebody of the car is given some severe bumps, even though thewheels themselves do not leave the track. Then, for addedexcitement, the body is whipped precariously back and forth,making the passengers feel that they are being thrown out

2

tbr.40,13W__ 1"114

- -

t.

UNUSUAL SURF-BOARD is illus-trated above. Theuser can propelhimself out into thewater by handpower. Ile projectshis hands throughopenings in thesides of the board.

MOTORLESSMERRY-GO-ROUND, illustrat-ed in the two pho-tographs at theright, was recentlybuilt in Berlin. Theoccupants operateit by raising andlowering the wings.This causes themerry-go-round torotate at a great

speed.

STARTLING ROLLER -COASTER here shown is an imitation automobile scenicrailway in which the bodies of the cars are swerved from side to side, and the pas-

sengers are further given a startling up-and-down movement.

or skiAding. Of course, ample safe-guards have been provided.

Something in the nature of a thrillthat is exciting both to the rider and thespectators is a huge "globe of death."as the inventor, E. E. Fillmore. ofOcean Park, California, chooses to callhis device. This is a latticed steel struc-ture 57 feet in circumference. In thisMr. Fillmore, who is a motorcycledriver, loops the loop in al directions.


BALANCE a baseball bat on a knifeedge. On which side of the knife

edge is the most material ? Are thetwo portions equal in weight?

LB0S

WE shall assume that weights inthe above pictures slide on the

scale without friction. Which of thetwo systems of weights will slide morerapidly? In which of the systems willthe tension of the cord connecting theweights be greater ?

Can You SolveThese

ScientificPuzzles?By Ernest K. Chapin

SUPPOSE that over a certain areathere is enough moisture in the clouds

and the surrounding atmosphere to causeone inch of rainfall. This would amountto over 70,000 tons of water to a squaremile. After all this water has fallen, isthe pressure of the air on the surface ofthe earth likely to be more or less than itwas before?

40,

THREE little girls, Lena, Lora, and Lettie,are playing on a teeter -toter board. Lena

and Lora are on one side and Lettie is on theother. They find that they can balance the board,when arranged as above, provided each one sitsas many inches from the pivot as she is poundsin weight. Taking all the weights as wholenumbers, if Lettie, who is alone on the one sideof the board, weighs 102 pounds, what do theothers weigh?

FADING manufacturers ofwatches recommend t h at

their products be wound in themorning instead of in the eve-ning. Why is it better for us towind our watches in the morninginstead of in the evening?

(.4nswers appear on page 564)

THE boy has his hand over half ofthe objective of the telescope. To

what extent will the boy's view be re-stricted when looking through the tele-scope under the conditions?

ICEBERGS are subject to depositionof layers of frozen sea water. Sea

water is salty. Is the interior of aniceberg salty ?

WHY do the negative plates of alead storage battery get very hot

if removed from the acid and allowedto stand in the air?


THOM F.DIS.N

DR. LEWIS PERRY Cu.. CHAS. LINDBERGD S. W. STRATTON GEORGE EASTMAN

Board of Judges who chose contest winner

Do You ResembleHENRY FORD

The Typical American Genius?0 NE chance in forty-

nine ! That was theodds facing young

Wilber Huston, I6 -year -oldAmerican genius and studentof science, hailing from theState of Washington. Sometime ago Thomas A. Edisonconceived an idea which wouldput the young science studentsof the country on their mettle.Mr. Edison said he would givea free scholarship in any tech-nical school or college the win-ner chooses, if he surpasses allthe other entrants in the test.

Elimination tests were car-ried on for many weeks byhigh-school teachers and pro-fessors, so that in each case theboy finally chosen to representhis state would be found wellequipped, both as to educationand character, in the na-tional tests to be conducted byMr. Edison at his famous lab-oratory in West Orange, N. J.Mr. Edison had the able assist-ance of several eminent men,including young America'sidol, Col. Lindbergh, in passingon the merits of the writtenanswers to the questions. Thejudges finally decided thatWilber Huston, son of BishopHuston, of Olympia, Wash.,had expressed the highest qual-ity of thought and judgment inhis solutions of the problemspresented. Some of the ques-tions involved mathematics,some chemistry, while others

THESE FIVE BOYS

Charles H. Brunissen, Con,nceticut, 'won scholarship

T h is compos?epicture of taetypical Am.rsccngenius embodies taefeatures of 49 boys

Bernard Sturgis, Indiana,also won a scholarship Wilber B.

Compare yourface with this

"ideal" study of49 young scientists

were intended to bring out thecharacter of the entrant in thetest. All in all, we think theidea was a very fine one. Mr.Edison presented each of theforty-nine boys, one from eachstate and the District of Co-lumbia, with one of his combi-nation electric radio and pho-nograph cabinets. WilberHuston, first prize winner, haselected to take up a chemicalengineering course at Massa-chusetts Institute of Technol-ogy this fall. All his tuitionand living expenses while tak-ing this course will be paid byMr. Edison.

Besides this Edison Scholar-ship awarded to Wilber Hus-ton, four other scholarshipswere finally decided upon, andthese were awarded to the fourboys who attained the nexthighest marks to Mr. Huston.Photographs of these fouryoung gentlemen, each wearinga pleased look, appear at thebottom of this page.

We congratulate WilberHuston, his f our associateswho also won scholarships. andMr. Edison. This contest hasdone a great deal to show thedeep interest being taken inscience by the youth of ourcountry. Another fact demon-strated by the tests was thatthe forty-nine entrants all ranclose together, the percentagesall being high. This speakswell for our high schools.

WON SCHOLARSHIPS

James Seth, New Mexico, As did Ivan A. Getting,representing Pennsyl7aniaHuston, Wash., Honor Man also won a scholarship


Would You Believe It?Truth Is Often Stranger Than Fiction.

Strange Things Are Here PresentedWith Photographic Proof.

Five -Dollar Yachts Always Fullof Water

A $5.00 reed yacht.

T NDIA balsas on Lake Titicaca1 are made of bundles of reedsor bulrushes tied together. Thesails are also of reeds. Theyare often of large size and willcarry several tons of cargo. Theyare exceedingly buoyant and safeand make excellent speed under sail.Lake Titicaca is over 12,000 feetabove sea level. It is on this Lakethat this type of boat can regularlybe seen. The cost of one of thesereed yachts of average size, sailand all, is less than $5.00. Theyachts invariably contain water.-Dr. A. Hyatt Verrill.

Crawling or Traveling DesertsONE of the most remarkable and

curious formations is the crawlingdesert of La Joya in Peru. Here thehard, dull -brown "puna" or high desertis covered as far as the eye can seewith white crescent -shaped mounds,which range in size from several hun-dred feet to a few feet in length, andare as perfectly symmetrical as thoughcarved. by hand. Each of the strangewhite crescents has its convex side to-wards the north and points towardsthe south and every one is beautifullysculptured with waving ripple -like lines.Wind invariably blowing from thesouth piles up the sand on the convexside and it falls on the opposite side.The deserts move at a constant rate of50 feet per year. This is the only placewhere such a formation is known.-Dr. A. Hyatt Verrill.

el fisherman standing up in the moutha whale.

of

Demonstrating the method of extract ny t,,,, Hill matterfrom the lungs.

Dummy Figure Helps TeachDoctors

IN order to demonstrate his method of extractingforeign bodies from the bronchial tubes and the lungs.

Doctor Franz Hasslinger, a Vienna doctor, employs amannikin. The chest of the mannikin is cut away to showstudents exactly how the instrument is made to pass downto the lungs and how it is manipulated when once in thisposition. A motor drive on the mannikin reproduces theaction of the heart and lungs just as if those organs werenormally functioning.

Above-The beautiful crescent formation ofthe traveling deserts in Peru.

Man in a Whale's MouthT T is quite possible for a man to stand1 up in a whale's mouth. Lest therebe some dispute about this statementthe photograph here will vouch for thetruth thereof. This is the open mouthof a 50 -ton whale caught recently out-side the Golden Gate in San FranciscoBay. The whale was towed into SanFrancisco, where it was to be convertedinto whale -oil soap and various other by-products of the whaling industry. Theproblem of getting the whale out of thewater was solved by using a derrickbarge. While the whale's mouth willeasily hold a man, the food of the whaleis very small.

Ever Hunt a Geoduck?WHAT is a Geoduck? Very few

people know this curious bivalve.For years there has been a ban onGeoduck hunting on the West Coast.The method usually adopted is to spearthe neck of the Geoduck when it pokesthis above the sand and then by diggingvery quickly one can get down to theshell. It is necessary to work very fastin order to capture them, because whilethey extend their necks to a tremendouslength, when frightened they draw themdown to a matter of but a few inches.The Geoduck is related to our soft-shellclam and its official title is Glytimerisgeneroso. It is found on the northwestcoast of this country and is much de-sired for its food value.

What a Geoduck looks like after it hasbeen captured.


CAMERAPLATFORM

CARRIEDON TRACKS

NOAH'S ARK LivesAgain for the MOVIES

By Edwin Schallert

N-T- OAH'S ARK was recently reconstructed by themotion -picture producer of the photoplay spec-tacle- bearing that name, and the pictures here-

with show some of the unusual engineeringand construction work that had to be per-formed before this remarkable film play couldbe photographed. Among the many spectacu-lar scenes in "Noah's Ark" there is shownthe complete destruction of a massive pagantemple, and the city of Noah's enemies isshown, as well as the survival of the patriarchand his followers, including the death of thefrantic, disbelieving multitudes who tried toseek refuge in the ark. (Coned on page 553)

PAINTED DROP 30FT HIGHAND 300 FT LONG

1090VAIWWAS51&.4--r_outo*:91'.X47,1KSWebriffe40217

Spillways lined the side of the tank andwere placed at other advantageous points.Hoses were used to agitate the water. .So

were numerous wind machines. There werealso overhead pipes to drip the rain. In thebackground (right) Was vista of mountainsand sky on painted canvas bark -drop. Reser-

voir was provided acith sluices.

In this temple set preliminary scenes of de-struction were first photographed. It wasoverhung with troughs and spillways. !losesand rain pipes were also used to producedownpour. Temple pillars were pulled downby wires. The idol was pulled down in the

same way.

Above we see ahuge tank inwhich artificialrocks and treeswere construct-ed and intowhich waterwas poured forthe flood scenes.Lower viewshows peoplefleeing fromfalling temple.

How huge millwheel was pulledapart at the propermoment by means

of wires.


/Move we s e e Houdinilocked in the "water -tor-ture" cell. This cell wasfilled with water and, ifall did not work right, themagician might lose hislife. The front of the cell

had a glass panel.

Houdini and his famous"milk -can" trick. In per-forming this dangerousact, a large brass m ilkcan was filled with water.Houdini then climbed intothe milk can, filled withwater to the brim, andthe top was locked on bya committee from the au-dience. If he failed torelease himself in a few

minutes, well . . .

When FATEHandcuff and Jail "Escapes" AlwaysEnthralled Us; but Suppose the Locks

Balked?

Houdini was anearly experimenterwith airplanes.Nearly 20 years agohe flew one in Aus-tralia with results

II a t nearly proveddisastrous. Duringthe filming of the"Grim Game," Hou-dini jumped fro mone plane to theother, hundreds offeet in the air, inorder to rescue the"beautiful damsel,"but it al m ost costHoudini his life. Nosooner had he jumpedfrom the plane,which flew abouttwenty feet a b o v ethe other one, whenthe top plane crasheddown on top of theother one. Thanks tothe quick thinking ofHoudini, no one wasinjured. "It was aGRIM GAME allright," said Houdini.

HOUDIN' !King of Handcuffs

showman superior . . . magi-cian supreme!

One of the greatest showmen of alltime, whose career was cut altogethertoo short by the Master Magician, whowields the magic wand and causes allliving things to come to an end.

Harry Houdini, accounts of whosesensational exploits throughout theworld have appeared in newspapers,magazines and even in motion pictures,used to hold his friends spellbound for

hours, telling of the many adventures, mishaps andexperiences that had befallen him during his years ofappearing before audiences the world over.

One day as we were sitting in Martinka's old magicshop Harry said to me, "Dunninger, one of the funniestexperiences I ever had was back in my old museum days.There was an old fellow who was a clever magician ofthe old school. Professor Schlamm was his name. Thismaster was one of the slow, patient, painstaking type ofconjurers, who went to any length to make things seemof a real magical nature and whose sleights were of thefinished sort. One night someone put tin plates in thebottom of the trap in his black art table. When theprofessor did his show, as each article vanished via theblack art well ( or trap in the table), an audible "click"was heard. The old fellow was beside himself, but putan unconcerned smile on his face until the show wasover. Then he set out on a still hunt to find the onewho played the trick on him. But his search was unsuc-cessful, and after that every time the professor wasabout to begin his performance one could see him care-fully inspecting the black art wells to assure himselfthat no practical joker had tinkered with his outfit."

Houdini also told about a magician, in Germany. whofeatured the production of live stock, such as hens,ducks and rabbits, from gentlemen's coats, hats andwhat-nots. One night this magician was performing,and, unbeknown to himself, one of the rabbits whichwas to be produced later from a high hat, got loose anddropped from the wizard's special pocket to the stage,

where it sat looking into the audience and blinkingits eyes. The audience howled, but the professor. . . well, a la Kipling . . . that's quite a differentstory.

The man who laughed at locks and bolts alwaysenjoyed a joke, whether he or the other fellowwas the victim. He was a good fellow always,and could laugh just as heartily at a joke on him-self as at the joke the other fellow had to stand

for.Many is the laugh lie had at the expense

of swindling spirit mediums. At oneseance Houdini, under cover of darkness,greased the trumpet and tambourine of thespirit medium, and when the lights wenton there sat the so-called communicator

with the great beyond, with handsand face well greased and smeared,much to the surprise of the gulliblebelievers and the hearty laughter ofI loudini's friends who attended thesitting.

While making one of his sensa-


Fooled HOUDINIBy Dunninger

DUNNINGER, the world-famousmagician and mentalist, who is

chairman of the Psychic InvestigationCommittee of this magazine, is con-tinuing the work of exposing fraudu-lent mediums as practised by the lateHarry Houdini. Dunninger has hada very similar career to that of Hou-dini, and it is not only the judgment ofthe Editors, but that of the theatricalprofession as well, that Dunninger isthe logical successor to Houdini, withwhom he enjoyed a very close friend-ship for many years, and we are surethat you will be delighted in readingthe many unusual and exciting experi-ences that Houdini related to hisfriend Dunninger, and which are hererevealed to the public for the firsttime.

tional escapes from an English prison,Houdini opened a cell door and con-fronted a prisoner who had been jailedfor imbibing too freely the night beforeand who wasn't quite recovered from thespree. Houdini, attired in a running suit,naturally frightened the intoxicated man,who let out a series of yells and shouted,"Never will I drink again ! Satan isafter me!"

Which, by the way, reminds me of alaughable incident that took place while Iwas appearing at the Metropolitan OperaHouse in Philadelphia some years ago,when I was heading my full evening'sshow of magic, mind reading and illusions.I presented during my performance an illu-sion known as Cremation, in which a younglady was placed on a small stand, coveredwith four large pieces of board; sides, frontand back, a shot was fired and the front ofthe assembled frame fell off and a grinningskeleton appeared.

On this night, before the curtain went up.there was a still hunt back stage and in factall over the house for three or four littlepickaninnies who had somehow or other suc-ceeded in getting into the theatre betweenthe matinee and evening performance. Theselittle imps had vanished completely, andneither the house, stage crew nor mem-bers of my own company could findthem in their hiding place.

Houdini played with fate thousands of timesduring his life, and it was always a battle ofwits to see whether Houdini would get out of acell like that above, when heavily manacled.Houdini often freed himself from these manacleswhen under water, and as a man can only stayunder water for a few minutes without breath-ing, it will be readily apparent that Houdini

took some mighty long chances.

During the presentation of the Cremationillusion, the front board had been put intoplace by my assistants, and I fired my re-volver, and when the skeleton came intoview, we on the stage, as well as the specta-tors out in front, heard a number of shrillscreams and a voice yelled out, "Lordy, bepraised . . .!" And down the steps, froman upper box, trooped the four black imps,startled out of their wits. The housescreamed, thinking it was part of the show.and my company laughed so heartily at theoccurrence that it took a few moments forthem to continue with the show.

Woven in with the heartaches and thetrials of the magician are also the laughsand moments of merriment. A good laugh isa stimulant, but the magical entertainerwould rather have the laugh on someone elsethan on himself, which after all is but natu-ral. But when anything goes wrong duringthe modern magician's show, seldom is itnoticed by the (Continued an page 556)


Time and Labor Savers

111110111111J111111111

111

Plug ProtectorPTI HE above illustration shows a use-

ful electric attachment which isreadily slipped on to standard plug capsof any size and is fastened in place bytightening a screw. No rewiring isnecessary and the two curved armsform a convenient grip for the fingers.The device also protects the plug capfrom breaking and is finished in 'blackto match the hard rubber or composi-tion plug.

Tripod HeadAN all -motion tripod head for ama-

teur moving picture owners, hasbeen illustrated above. This attachmentis fastened on to the regular tripodstandard and permits the camera to beswung in all directions. The arrowsindicate the freedom of movementwhich is accomplished by simply mov-ing the handle attached to the tripodhead.

Iceless CoolerTHE photograph at the

right shows an icelessbeverage cooler which issimilar in construction toa vacuum bottle. A chem-ical is poured into thesmaller cylinder at theleft, a small quantity ofwater added, and thechemical container placedwithin the cooler, whichcontains the beverage. Icecubes may be placed inthe chemical container ifdesired.

NON -AUTOMATICOUTLET

AUTOMATICOUTLET

SWITCH

Shadow BallPr HE illustration below shows a new1 type of punching bag which can beused as a substitute for shadow boxing.The ball is attached to an adjustablehead band, by means of a heavy elastic.When the ball is punched, the same

Automatic TimerADEVICE which auto-

matically turns off thecurrent supplied to an elec-tric toaster, percolator orsimilar appliance is shown atthe left. The time adjust-ment lever is set to any de-ired position and the switch

turned on. A clock -workmechanism flips the switchoff at the desired time. Anautomatic and a non -auto -

TIME matic outlet are provided.ADJUSTMENT

LEVER

action is obtained as in both shadowboxing and bag punching. Balls cov-ered with leatherette or sheepskin, arealso available.

Names of manufacturers supplied upon request

Ball -Bearing GearAGEAR DRIVE is shown in the

diagram above in which the ordi-nary teeth of the wheels are replaced bysteel balls. Turning the gear in the di-rection of the arrow, the balls fall fromthe right into the opening at the top,the lower wheel catches the balls andthese gear into the upper wheel, untilthey go to the left, where the balls arefree, and run through the housing tothe bottom of the wheel.-Tcchnikfuer Allc.

October, 1929 Science and Invention 5n7

(Conclusion)

Coal Miner's JobSafer Than Yours!

Listening, by meansof sensitive instru-ment, to sounds inanother part of mine.

REVENTABLE accidents," says the Bureau ofMines, "are generally attributed to carelessness, in-sufficient inspection, inexperience, unsafe practices,

lack of safeguards, violations of instructions, indifference.defective equipment, use of intoxicants, insufficient lighting.poor judgment and other indirect causes." It is thereforenot always and entirely the miner's fault that he is hurt.The campaign of education must extend to shot -firers, bosses,superintendents and even to some managers and employers-though there arc few mine owners nowadays who do notclearly realize the value of safety and do what they can topromote it. As a matter of fact, some of the largest miningcorporations have been leaders in devising safety methods,putting them into practice, educating their employees andinciting them by means of contests and rewards to usegreater care.

Self-preservation is supposedly the first law of nature, butthe surprising thing is that men cannot be induced to Nvorkfor safety for the sake of their own arms and legs and livesas enthusiastically as when their plant is put in competitionwith others in a contest for the lowest number of fatalitiesor disabling accidents. Wherever contests of this kind arestaged, accidents decrease in number much more rapidly.Of course it must be admitted that superintendents andbosses are also influenced by the spirit of the game to theextent of strengthening all safeguards and showing greaterzeal and overseeirv, and exhorting the men.

Contests of this kindare now going on all over America.The United States Steel Corporation throughout its morethan 250 operations (including mines, quarries, furnaces,mills, railroads and repair shops) maintains a "Star Bulle-tin." Each operation working for a month without a dis-abling accident is entitled to put a star on its bulletin at plantheadquarters and also appears on the printed bulletin regu-larly issued by the Safety Bureau of the corporation in NewYork. The rapid increase in the number of stars shown inthese bulletins is rather amazing when one considers that amashed finger which will keep a man away from his workfor one day will disqualify the plant for a star that month.Among their iron mines in Minnesota and Michigan, coalmines in Pennsylvania, Tennessee and Kentucky and bothcoal and ore operations in Alabama there are some whichhave been able to operate for a year without a disabling acci-dent. Trophies are given to the subsidiary company and tothe particular plant having the best record, and all sorts ofbronze tablets, banners and banquets to the departments and

Above -11 o w trackswitch is extendedinto a hole in thew all and prevents

danger to miner.

gangs which makethe best showing.And each y earsome plant erects atriumphal arch, in-dicating its su-premacy in satetyover all other op-erations of the cor-poration for theyear.

A trade journalhas prepared threereplicas of a bronzestatuette of artisticand symbolic de-sign. Which aregiven respectivelyto the plants mak-ing- the best yearlysafety record incoal mining, metalore mining andquarrying and openpit work. At a zincmine in Tennesseethe safety contestsbetween variousgangs are symbol-ized by a miniaturehorse race in thewindow of thecompany's st or ewhich arouses in-terest equal to thatof a world's base-ball series. Inthe Nlissouri-Kan-sas-Oklahoma leadand zinc districtthe miners h o 1 dwhat they call kan-garoo courts, t it emen themselves serving as judges and attorneys, and assessactual fines upon workmen guilty of caning accidentsthrough negligence, and thereby (Conh zitc,/ on page 569)

By Alvin F.Harlow

Photos likethis, show-ing how barmay touchtrolley 'wireand causedeath, areused to warn

miners.

Dune fore -m a n testingventilationcurrents in amine with afan -like in-

strument.

Telephone al-cove in a mod-ern mine. Tele-phone lines con-nect the variousgalleries w i t Ii

the surface.

Above photoseourle-y S.Bureau of Mines

Photo courtesy U. S. Sled rot 1..4 motion -picture a:Allot-item in a

mine, 215 feet underground.coal

50g Science and Invention October, 1929

.1 strange o, upation. The man in the center sup-ports two others by a sharp sword placed across his

neck and shoulders.

JUST why is it that sunk` people takechances with their lives? The answeris that some du it for economical pur-

poses and some for advancing the art of

A death -defying trick. With the point ofa sword plated against the back of hisneck, this artist holds a stick of dynamitein an improvised cannon in his mouth. Ifthe recoil jars his head back when thedynamite explodes, we can write "finis" to

this effect.

spurt. Not long ago, the audienceof a famous circus was astoundedwhen they saw a living human beingslide into the mouth of a cannonand a moment thereafter saw himhurtling through space, landing in anet a considerable distance away.I lyre was a case where a man sub-stituted himself for the shell as aload for a cannon. Of course, therewas some trickery involved, but ifanything went wrong with the ap-paratus, if the spring did not throwhim into the net, if he did not knowhow to tumble properly, or how toadjust his body so that he could

Playingu ith

DeathDangerous Perform-

ances for a Living orOutdoor Sports

By N. A. Foazrim

Looping the loop, while a man supports the unturatui, ,ombines both sk:11 and daring.


Should the jaws of the alligator dose atthis moment, the audience would nut ap-

plaud the prowess of the actor.

break the fall, there would have been many lapses betweenthe individual demonstrations, the rest of the time wouldprobably have been spert in the hospital waiting for thebroken bones to knit. In tis particular case the stunt wasperformed primarily for economical reasons, but there areothers where the stunt is performed purely because of

For exercise, this woman takes a leap from a third -story window to the pavement below. In this way she

!mint her livelihood.

deviltry, because of the publicity at-tending such a demonstration, becauseof the desire of "showing off," or forsome other physical or mental reason.The human being likes to acquire cer-tain faculties which have supposedlypassed the stage of normalcy. He likesto be noted for accomplishing one cer-tain act or one certain deed better thanhis fellow men. Some of us want thatact to be one of prowess, others findthat it takes a path towards sciences orarts.

We frequently hear of prodigies. Or-dinarily, these are individuals gifted inone particular field, usually they are notnormal in others. They know perhapsmore than a normal student of this oneparticular field, but the mentality runsin a channel widely divergent from theordinary course of intelligence. All ofthe person's energy is directed alongthis one set path to the exclusion of anyothers.

Thrill performances can frequentlybe likened to those which a prodigywould give. Such performances arenot new. Long before our presentcivilization, or in fact, any civilization,men have tried to do things that toordinary people would seem impossible.History will record many thrilling per-formances which have never been dupli-cated by any human being. Perhapsthese were exaggerated, as time handeddown the legends. Frequently thesethrill performances were mere figments

of the imagination. On rare occasions the stories aboutthem were based upon fact, but 1 Continued on page 575)

modernversion ofilliamTell. Jet -u-reic), of thearcher andnerve steadi-ness of hisassistant areprime requi-

sites.


The above illustra-tion shows the sizeof a pyramid of oneday's dust as com-pared with the Wool-worth Building. Onclear days 2,100 tonsof dirt, dust and cin-ders are present inthe atmosphere of

New York City.

DUST!2,100 tons of dust foundon clear day in NewYork City's trillion cubic

feet of air

The photographabove shows Prof.H. H. Sheldon, ofthe Physics Depart-ment of New YorkUniversity, settingin motion the clock-work of a machinewhich automaticallydetermines theamount of dust in

the air.

THE prevalency of pulmonary andrespiratory diseases in New YorkCity, which are most noticeable

during the windy months of the winterand spring, may be attributed to the tonsof dust, dirt, cinders and other foreignparticles which hover in the air of thegreat city. The one trillion cubic feet of air, which con-stitutes the atmosphere of New York City, contain at a mini-mum 2,100 tons of dirt, according to Prof. H. H. Sheldon,of the Physics Department of New York University, whohas been assisting the Health Commissioner in a campaignto rid the city of unnecessary smoke and dust. The calcula-tions are based on a study of New York City's air, madewith the assistance of the Carrier Engineering Company.

At the Roxy Theatre 62,500 cubic feet of air a minuteare purified, and during a week, figuring on a basis of seven13 -hour days, 341,250,000 cubic feet of air is cleansed. Inthe chambers where the air is purified there is an area of180 square feet, which is covered to a depth of three-quarters of an inch with dust, dirt and similar matter. Sincethe purifying device is about 96 per cent. efficient, it is cal-culated that the air sent through in one week actually con-tained 1L72 cubic feet of dust and dirt.

2,100 Tons of DirtCONSIDERING the square mileage of New York City

and taking a perpendicular distance of 200 feet as theimmediate atmosphere, the total equals one trillion cubicfeet. If the 341,250,000 cubic feet of air examined at thetheatre contain 11.72 cubic feet of dust particles, one trillion

Prof. Sheldon claimsthat the dust -ladenair is greatly respon-sible for respiratorydiseases. He is shownabove with the dust -recording apparatus. The amount of

dust floating overNew York Cityon a clear day isequal in weightto the weight of14 elephants of

average size.

cubic feet would contain about 3.000times as much or about 35,160 cubicfeet, which would weigh 2,100 tons.

As the tests were made in the vicinityof Times Square, which is relative!:free from smoke, there is every reasonto believe that the estimate is a con-servative one for the entire city. Inmanufacturing sections the density ofdust in the atmosphere is probably muchgreater.

The huge amount of dust present dur-ing one day in the atmosphere of NewYork City is equal in weight to theweight of 14 average -sized elephants,and if stacked in the shape of a pyra-mid, would reach a height of 400 feetwhen the base measured 200 feet. Thisis illustrated in comparison with theWoolworth Building.

What Is Dust?WHEN atmospheric dust is col-

lected and examined under amicroscope, it will be seen to containbits of vegetable fibre and all kindsof mineral fragments. When dust isallowed to settle upon cultures andkept in a warm room, a vigorousgrowth of bacteria usually is visiblewithin a few days. This shows thatliving germs are preSent in the at-mosphere, although they may be in-visible even under the microscope.Some of these germs are injurious toman and animals and others, when

brought to the ground by rain, may germinate on the wetsoil and produce fungi.

John Aitken of Scotland has shown that in the process offormation of a cloud or fog by cooling air the condensationof the moisture takes place first upon the particles of dustas nuclei. Every particle of dust collects moisture and uponthis principle is based the construction of the dust counter.According to Aitken's findings in the cities of London andParis, there are from 80,000 to 210,000 particles of dust percubic centimeter. The air having the least dust is that ofthe western highlands of Scotland, which has from 7,600down to 16 particles per cubic centimeter.

When dust is finely divided and the particles rather uni-form in size a beautiful optical phenomena becomes evi-dent, due to the diffraction and interference of light. Thisis noticed during the times of sundown and sunrise, whenred, green and yellow colors are mostly visible. After vol-canic eruptions, when much dust is present in the air, the sunappears blue during the daytime. (Continued on page 542)


Light Controls MachineTHE old electric pup which responded to a beam of

light-started, stopped, barked, and followed in responseto flashes of a light beam-has been brought up to date.The Westinghouse laboratories have conducted some recentexperiments on a new and improved method of control bylight. The results are more positive with thisnew apparatus and operation may be obtainedwith a weaker source of light than heretofore.This means that the apparatus can be con-trolled from a greater distance making thefield of usefulness greater. The selective relaymay be constructed to operate any number ofdifferent pieces of apparatus. The controlapparatus is very compact and light in weight.

MovieAbove-The li-brary Kodascope,open and ready for

projection.

At left-The li-brary projectorpresents an attrac-tive appearance,folded and enclosedin its neat -looking

walnut case.

AROTARY gasoline enginehas long been the dream

of scientists and inventors. Arotary engine without poppetvalves, gears, camshaft, push rods, orsprings, which is air-cooled would be con-sidered ideal. All thesefeatures are incorpo-rated in the AugustineRotary Engine. Thecompression, im-pulse, expansion,momentum and cen-trifugal force alltravel in one direc-tion; therefore, therecan be no poundingin any of the bear-ings, all forcescreating a constant torqueand producing power. Thelightness and efficiency ofthe engine make it a goodpower plant for airplanesas well as automobiles.

SELECTOR CELL

SELECTINGRELAY

.aCIPERATOR

CELL

IN

Diagram of thelight control appa-ratus set up to op-erate a lamp, ahorn, and a fam

selectively.

The complete apparatus as set up in the Westinghouse labora-tories. The light-sensitive cells are enclosed in boxes, so that they

operate only from a direct beam of light.

Projector for Your LibraryHERE is a motion picture projector that may be used

right on the library table. It is not necessary to havea clumsy separate screen which must be stood in a corner;everything folds into a small box which takes little moreroom than a reading lamp. The screen supplied with theLibrary Kodascope is translucent; pictures are seen throughthe screen instead of being reflected as heretofore.

Due to the fact that light is direct, the pictures viewedon the translucent screen are surprisingly brilliant andbeautiful.

Rotary Auto Engine

Diagram of the rotary mo-tor. Below-The motor in-stalled in a car, showing

compactness.

512 Science and invention October, 1929

THE Trading Room of theNew York Cotton Exchange-like all other rooms of that

nature-has always been a bedlamof sounds during trading hours.Today one cotton broker's raucousvoice can be clearly distinguishedfrom another's nasal drawl. Thechange provides an audible demon-stration that the baffling problem ofhall acoustics-the despair alike ofarchitects and speaker,-has beensolved. And appropriately enouzhthe solver of the problem is Emile

MakingBy John De Quincey

Berliner, whose invention of the tele-phone transmitter-known in radio asthe "mike" - and the gramophone-known now as the Victor Talking Ma-chine-has closely connected his name

with the subject of soundtransmission for over halfa century.

Up to the present timethe method generally used

The photograph ut thetop of the page shows theDrexel Institute Audi-torium. Directly above

is a workingman rip-ping off the panel-

ing, of heavy felt.

Every Room Like an Organ PipeAn organ pipe emits a certain note when a rhythmic vibrationis set up by the agitation of its air column. This principle alsoeon be applied to auditoriums or rooms. The illustration at theleft shows how the acoustic cells function. They transform areverberating "booming" hall into a chamber where everysound is clearly understood. The sounds upon striking the

acoustic diaphragms are "sprayed" back in a diffused form.

to remedy the reverberations in a ball was to pad the wallswith felt or hang heavy draperies about the room. Thishelped to relieve the reverberations, but in their place camea certain deadness of sound-the resonance was gone.


Sound Behave!How Emile Berliner's Vibrating WallCells Prevent "Booming" in Auditoriums

Berliner's invention not only eliminates the reverberationbut increases, instead of killing, the resonance. It is a mostsimple device. A section, or unit, of a wall treated with thisinvention gives the appearance of a smooth nine -inch squaretile of about a half inch thickness. The under side revealsa circular depression eight inches in diameter and a quarterof an inch deep, lined with a galvanized wire netting. Thesubstance of the "tile," or "acoustic cement cell," as Ber-liner describes it, consists of a special kind of porous cementmixture.

These acoustic cement cells massed -together form whatappears on the outside as a flat cement wall. The finishedwall thus consists of a series of concealed diaphragms, en-dowing an otherwise rigid wall with the same vibratoryquality possessed by a wooden structure. And it is theacquirement of this vibratory quality that transforms areverberating "boomy" hall into a chamber where everysound spoken is clearly understood. The sounds on strikingthese diaphragms are not reflected back as beams or shaftsof sound, as would otherwise be the case, but are "sprayed"back in a diffused form and with amplification of volume.The amplification is due to the fact that every sound emittedfrom the stage is "sprayed" back to each auditor from threewalls.

Berliner's patents in connection with this subject are verysweeping, covering any method of treating a wall with anumber of diaphragms or similar partitions, made of cemen-

A clarinetist playsan ascending scalein front of a violinencased in cement.When the note isreached which cor-responds with theviolin's body of air,it is sounded fortiswith several timesthe volume of othernotes. No resultsoccur with an ordi-

nary violin.

The above photograph shows Emile Ber-liner, the inventor, watching the manu-facture of the wire cells forming the

groundwork.

At left: The recently "treated" tradingroom of the New York Cotton Exchange.

Below is a close-up view of the "treated"wall and of a wire cell which forms the

base of the "acoustic cement cell."

titious material. The dia-phragms need not be round.They may be of any size, pro-vided the thickness is kept inproportion to the diameter.

The invention seems like simplicity itself-as valuableinventions often seem to be. But the work that preceded it,and the formulation of the principles on which it is built,has consumed a number of years. In fact, it may be doubtedwhether Berliner would ever have conceived or perfectedthis invention had it not been for his extended technicalknowledge of acoustics, which covers more than a half cen-tury. An understanding of this background is necessary toan appreciation of what Berliner has really accomplished.

His invention grew out of two basic propositions. Thefirst is this, to quote his own (Continued on page 551)


The magician makes use of a rubber tubeand a telescopic reaching rod, as shown.

The Wizard's MintTHE magician requests the limp of a

$20 bill, but his audience is not in-clined to give him this. In a nonchalantmanner he places a cigarette betweenhis lips and, showing his hands unmis-takably empty, he picks up a cigarlighter (or cigarette lighter, whicheverterm you prefer) and proceeds to lightthe cigarette. He puts the lighter on anearby table; then, cupping his handstogether, he produces a $20 note, appar-ently from the cigarette. Secret : Theconstruction of the lighter is responsiblefor the production. The bottom of thelighter has an extra fitting in the formof a receptacle which will hold a bill ora tightly rolled handkerchief, and theproduction of either the kerchief or thebill is from this portion of the lighter.The device can also be used as a vanish.

EMPTY

OTTOM

LIGHTER

20 DOLLARILL

111111111111111111 11111' 1111

4 pocket cigar lighter can be so changedthat it can be converted into a bill.

The magician, securely bound, is placed ina cabinet and a glass of water is put onthe table in front of him. He drinks thewater out of the glass from this position.

MAGICB y

NO. 74 OF A SERIES

The Spirit That DrinksTHE demonstrator, even though se-

curely bound, shows that he is ableto drink a glass of water, mounted onthe table in front of him and out of hisreach, just ex-tinguished. The bindings are nevertampered with. Secret : Concealed wherethe magician can easily get at it, he hasa telescopic reaching rod, to which along piece of rubber hose is attached.The rod is pushed through the curtains,the hose dipped in the water and theother end enters the magician's mouth.

Showing a paper of matches empty at first,a simple pass fills the paper with good

matches.

Mysterious MatchesFIRST, showing the paper of matches

empty, the magician closes theholder, makes a few passes over it, thenopens it and demonstrates the paper isfull. Secret : Paste the black strikingstrip across the lower edge of a fullcase; hold case so as to conceal matches.

How the rubber tube is attached to thereaching rod is here indicated.

Supreme Court MysteryACARD is chosen by a spectator,

then returned to the deck. Thedeck is completely shuffled, after whichthe individual cards are placed side byside on the rack. A spectator is thenrequested to blow a dart at any of thecards on the board. He is given freechoice. Upon removing the dart andshowing the face of the card to theaudience, it is found to be the one se-lected. Secret: On back of the board isa suitable bag and holder containing adeck of cards, all of one suit. The origi-nal card is forced. Under the act of push-ing the board in place, the magiciandrops the shuffled pack into the bag, ex-changing it for the prepared deck.

Naturally, any card the dart strikeswill be the ace of spades.

BACK OFBOARD

A shuffled deck is arranged on a rack. Anyspectator blows a dart towards the cards

and selects the ace of spades.


The largest flying boat in the world in its hangar.

Germany's i2_o-Passenger,Twelve-Engined, Trans-

Oceanic Air LinerTHE largest flying boat in the world has recently been

finished at the works of the German Dornier AircraftCompany on Lake Constance. This immense flying

boat required the services of 500 men who labored for morethan 2l:., years to complete it. The wings are covered witha new super -strong fabric and the 12 siemens -Jupiter motorsdevelop a total of 6.300 horse -power. which is more thantwice the available horse -power on the -Graf Zeppelin."The vessel 1x- i 1 1 carry a crew of ten men and 120 passengers,together with their baggage. Whilenot primarily intended for trans-oceanic flights t the average cruisingradius when fully loaded being 500miles). by cuttingdown the numberof passengers andincreasing thefuel supply. thevessel could easily cross the ocean.Light of the 12 engines suffice tocarry the vessel into the air andmaintain it in its flight. It is thusobvious that motor repairs could beaccomplished without the necessityof bringing the ship down. _

Interior view of world's most massive airplane. Numbers referto 1, pilot's compartment and bridge of captain and navigator;2. engine control room; 3, radio room; 4, commander's quarters;5, baggage and store room; 6, passengers' cabins; 7, com-panionway and hatch between k

decks; 8, dining saloon and if,social hall; 9. officers' quarters;10, galley; 11, crew's quarters;

12, fuel tanks.

11

' WE

This vessel will travel at aspeed of 155 miles an hourwith only eight engines go-ing. The ship is 149 ft. longand has a wing span of

157 ft.

3 top view of the 12 -motorhornier flying loaf now

undergoing trial tests.

On this board one can immediately see how,any one of the motors is acting.

Here is where the-n. 0. X. is eon -

trolled.


Risky moment in midair when oneof the pilots of the "St. Louis Robin"had to crawl out on a cat -walk torepair the engine. Unusual credit isdue to these endurance fliers, as theymust possess daring as well as

strength and skill.

If the "St. Louis Robin" hadflown in one direction, itcould have encircled the

globe.

25,000 MILESWITHOUT LANDING

ALL world records for flying an airplane by refuel-ing from another plane in midair were recently

broken by Dale Jackson and Forest O'Brine, whenthey flew their plane, the St. Louis Robin, over a con-tinuous flight of 420 hours, 21 minutes and 30 sec-onds, exceeding by more than 173 hours the previous

Nv or 1 d s record for endurance flightsset on July 12th at Culver City, Cali-fornia, by Reinhart and Mendell.The new record was established atSt. Louis.

1

Gasoline and oil! This picture gives you some ideaof the tremendous amount gasoline and oil usedin, such a remarkable 420 -hour flight as that of the

"St. Louis Robin."

Can You Answer These Science Questions?/THE following questions on general science can be1 answered, if you have carefully read the articles

appearing on the pages mentioned. If you have readthese articles, then you will find it a good test of yourmemory to try and answer the questions before turningto the page numbers cited. I f you have not already readthe articles, you will undoubtedly find it very worthwhile to study the articles referred to. for the very goodreason that practically no one today considers themselveswell read unless they possess a fair knowledge of scien-tific subjects. Here are the questions:

1-How long did it take the new German steamship Bre-men to cross the Atlantic Ocean? See page 488.

2-In what way would an airplane help to fight a fire in atall city building? See page 490.

3-Does the Graf Zeppelin carry one or two kinds of gas?If so, what is the purpose of the second gas carried? Seepage 491.

4-By what electrical means does a passenger on board thethe new German ship Bremen ascertain how to get fromone point to another on the ship? Does the Bremen burnoil or coal as fuel for the boilers? See page 494.

5-How many tons of dirt are there in the atmosphere of alarge city like New York on a clear day? What is yourdefinition of dust? See page 510.

6-How are "storm effects" produced in larger motion -picture scenes such as those appearing in "Noah's Ark"?See page 503.

7-How many passengers does the world's largest seaplanecarry? How long did it take to build it? See page 515.

8-What simple apparatus would you employ in order tosee the whirling blades of an electric fan as if they werestanding still? See page 534.

9-Where and what are the "crawling deserts"? What is a"Geoduck" and how are they hunted? See page 502.

10-Did you know that there is a new drink cooler whichoperates by means of chemicals? Did you ever see a geardrive for machines, the gear teeth being formed of ballbearings? See page 506.

11-Name five reasons why you think preventable accidentsoccur in coal mines. See page 507.

12-What railroad is interested in building a gigantic newbridge across the Hudson River at New York City? Howmany railroad tracks will this bridge carry? See page 492.

13-How can a beam of light be made to control machinery,that is turn it on and off? See page 511.

14-How did the late Emile Berliner solve the problem ofeliminating reverberation or echoes in auditoriums? Seepage 512.

15-As is well known, sea water contains a small percentageof salt. Would you conclude from this fact that the in-terior of an iceberg is salty? See page 500.

16-How would you grow new plants without the use ofseeds? See page 518.

17-If you were asked to make simple home "talkies," howwould you proceed to solve the problem? See page 522.

18-Did you know that compressed air can be made to liftwater from great depths in a very simple and economicalmanner? See page 524.

19-If you had to machine or turn a piece of metal whichwas too large to swing in the lathe at your disposal, howwould you proceed to accomplish the task? See page 529.


Fig.1-Therelativistplaces a suit -c as e on theseat of a mov-ing merry-go-round. Onthis he puts a ball. 'Which way does the

ball roll?

A Merry -Go -RoundDemonstrates

Einstein's TheoryBy Donald H. Menzel, Ph.D.

THE reader will recall that we left ourthree relativistic friends in an amuse-ment park, where they were finding

out that the theory of relativity is by nomeans out of their experience.

Layman-Although I have followed yourreasoning closely, there is always a littlevoice in the back of my mind that says,"Why bother with relativity? Isn't simple,old-fashioned gravitation good enough foryou?" After all, it doesn't make very muchdifference does it?

Relativist-I can sympathize, although Ido not agree with you. Until now I havescarcely dared to make this statement, forfear that you would laugh at me. But heregoes. Relativity is really more simple thangravitation!

L.-Astounding!Physicist-That's a new one to me. I

have heard it said that the Einstein theoryis so difficult that scarcely a dozen men inthe world can understand it.

R.-That last is all talk, of course. Thereal difficulty with relativity is not its appar-ent complexity but its new-ness.

Recall how the contem-poraries of Columbus ridi-culed the idea of a spheri-cal earth. "Do the peopleat the Antipodes walk ontheir heads?" they asked.Only the other day I over-heard two negroes arguingon a street car. One ofthem, apparently just re-turning from some scien-tific lecture, was saying,"Imagine him insultin'mah intelligence by sayin'that the earth is roun' like

Fig. 2 atright.

a ball an' spinnin' like a top. Imagine tellin'cue a thing like that. If we's on top of theearth now, why in twelve houahs we'd behangin' head down, an' tell me-why don'twe fall off !"

P.-If the question were put to popularvote throughout the world, there is no doubtbut that thereturns wouldbe overwhelm-ingly in favorof the ancientidea that theearth is flat.

R.-And whatpercentage ofthose that casttheir vote for'the sphericalearth have any-thing more thana blind beliefthat it resembles(Continued on

page 550)

Fig. 6-Arock andscale arethrown soas to leavethe earth.Scale regis-

ters zero.

Fig. 7-Anyonewould pre-fer the pathABC to thestraighterpath, .4DC.

Why? ..... -------- - "la

=/*

Fig. 2-The ball ona rotating merry-go-round tends tomove directly awayfrom the centerand in a straightline relative to thesuitcase. Centrifu-gal force might beexplained as at-traction from out-side or repulsion

from center.

Fig. 3-0 ne mightconclude that bandat center was re-

pelling ball.

Fig. 4-If, as illus-trated at left, thescenery were paint-ed on a backgroundthat could be ro-tated backward,anyone "riding" onthe merry-go-roundwould think thathe, rather than thescenery, is moving.


Grow N ew PLAN TS71frarritior

I\\

Right, propagating carna-tions. Split carnation stem

from node to node.

p!ANTS are usuallymultiplied and raisedwith seeds, and many

of them come true to type,but there are many otherplants so highlycultivated that itis impossible touse their seeds,for such plantswould then be de-generated and goback to their wildform. In order toprevent such anoccurrence, othermethods of mul-tiplying plantsmust be found,and. by experi-ments through the ages, twotypes of propagation withoutseeds have been developed.These are grafting and propa-gation through cuttings.

The method of propagatingplants with cuttings is one otthe most peculiar problems otthe plant grower, not becauseit is so difficult. it is simple,but because each type of plantrequires a little differentin ethod for its successfulcompletion. At present onlycertain plants may be multi-plied by this method. Furtherexperiments along this linewill undoubtedly increase thenumber of plants that may be so treated.

It was not so very long ago that a method for propa-gating hybrid carnations was developed. By this meansany form of carnation may be kept true to its type. a con-dition almost impossible when they are raised from seeds.as they are much too variable in form, color and shape.The cuttings are made from strong flowerless shoots dur-ing July or August. With a sharp knife the shoot is splitfrom one node to another. This forms a tongue. Theshoot is bent to the ground into a slight excavation and isheld in position with a small twig :laving a hook at itsend. The tongue is kept vertical and the depression istilled with soil. This cutting is still united with themother plant and it receives its nourishment from it. Theother end or tongue will develop roots in about four to six

'weeks. Then it may be cut from the mother plant and

Left, the splitend is sunk into

the ground.

Placing cuttings of privetin a ditch.

1,evir

Here the stem is being heldin position by means of a

small forked stick.

GardenPlants EasilyPropagated

By theEminentAuthority

kept in puts in some frost -free room or. cellarduring the winter. It is transplanted out of doorsin the spring. During root tormation any flow-ers that may develop should be pinched off.

The propaga-tion through cut-tings also enablesone to quickly ob-tain large andwc11 developedplants in a com-paratively shorttime. The Pelar-gonium. alsowrongly knownas the Geranium.is usually trans-planted from thegarden into potsand placed in afrost -free cellaror room. At thistime the shoots

are pruned back. the mature shoots being used ascuttings to propagate tile plant. These are placedin light sand in a hotbef I.. and i f a hot bed is notavailable, then they are placed in large flower

pots, the cuttingsbeing placed nearthe edge of the pot,at which point theywill produce rootsmore readily. Keepthe soil slightlymoist and cover witha glass globe. keep-ing the dish away

Left, a shoot of Pelargoniumbeing prepared as a cutting.

:Move, shoot is sunk into theground and held with a stick.

Propagating goose-berry. Girdle thegooseberry twig anddig a shallow trench.

Place twig in thesoil, cover with soiland hold twig with

forked stick.


Without Any SEEDSSystem of

Cuttings andLayeringExplained

DR.

ERNESTBADE

from the sun for thecuttings have rootedsmall pots.

A cutting willproduce its rootsmost readilywhen it containsa comparativelylarge amount ofreserve food andwhen it is plantedas soon as pos-sible after cut-ting. The onlyexceptions to thisrule are the vari-ous plants con-taining milky orresinous sapssuch as the succu-lent cacti. Theseplants must dry

Put t h e Begonialeaf in water andin a short time anew plant will

form.

Cut off the o Idleaf and trans-plant the new.This gives us a

new plant.

The rooted gooseberry is cutfrom the mother plant and

transplanted.

first two weeks. When thethey are transplanted into

Place Bryophyllumleaf on soil in aflower pot and cover

with glass.

Notch the leafof Bryophyllum.

Cut off the leaf of a Begonia.

Nev., plants developfrom this one notched

leaf.

.4 branch of Tradescantia isused as a cutting.

their cut surface before theybe planted, and this may

take a few days.It is best to drythe cut in the sun.and, when dry, itis placed into soilwhich should notbe too moist. Thisis the most rapidmethod of propa-gating such types.

A number oftrees will alsogrow from cut-tings, probablythe best knownthat will do thisare the willowsand poplars. Thetime to make cut-

tings is early in spring before the leavesbegin to grow. Cuttings may be a fewinches in length or they may be a fewfeet long; in fact, freshly cut poles sunkinto the ground root just as easily as thesmaller cuttings.

Many bushes and shrubs may be mul-tiplied by this method. Here shoots afoot in length (Continued on mg,. 568)

The Cutting and Layer Method offor Old

Cuttings to Be

Placed in Water

Coleus.

Begonia rex.

Oleander.

Rubber tree.

Cuttings to BePlaced in Shady

Places

Boxwood.California privet.

Poplar.Pelargonium.Cactus.Tradescantia.

Getting New Plants

Layers, BranchesHooked to theGround and

Covered with Soil

Gooseberry.Currant.Rose.Grape.Flowering bushes.Carnations.Barberry.


Car

FRONT VIEW

PIPE ELBOWS

PIPE TEES

PIPE

---- NOZZLESCONVERGE

NOZZLE

washer installed in the garage.

Labor -Saving Car WasherABETTER method for washing

was recently installed in a privategarage. At the entrance to the garagea pipe line was connected through avalve to the water supply. This piperuns along each side and across the top.Five nozzles are arranged to convergethe water. These nozzles are simplypipe with flattened ends. The car isdriven sloivly through this stream ofwater, which reaches practically all thesurfaces of the car. If the car is verydirty, it is sponged over after the firstrinse, with soap and water, and thendriven through the washer. Usually,however, daily baths with this washerare sufficient to remove

Flanging Copper PipesPr HE flanging of pipes for connecting1 joints in oil or gasoline lines is

simple enough if the owner selects theproper tools. Two examples of how toflare pipes are shown in the sketch.The first of these is a flare made byclamping the pipe between two blocksand tapping on a conical head wood or

HAMMER

CONICALDHEA

SCREW

VISE

COPPER

..------ WOOD41011'747 DLOCK5

COUPLING NUT -7°.

HANDLE

DENO TOFORM FLARE

PIPE

Showing two methods of flanging copperpipes.

machine screw, thus forcing the metalto flare outward. When it is not con-venient to remove the pipe, it is pos-sible to select a piece of steel having adiameter of that inside the pipe. Thisis bent as shown in the sketch. Holdingthe pipe in one hand and the tool in theother, the tool is rotated as an auger.This creates a good flare by a sort ofspinning process. Avoid the use oftwine or makeshift "leak" seals. Aproper flare makes a business -like job.

Motor HintsConducted by George A. Luers

Close Engine Hood in WinterHERE is a quick and ready method

to retain engine heat in winter,keep snow and rain out of the dis-tributor, off tires and off the carburetorand to insure ready starting. Twopieces of dense fiber board, large enoughto cover the louvers in the engine hoodsides, are secured with brass paperfasteners. The fiber board is preferablya heavy grade, such as is used for car -

The closures installed, showingare fastened.

tens and shipping packages. The paperfasteners hold this tight inside the en-gine hood, so that the paper does notshow except through the apertures.The board may be tinted some color thatwill blend with the trimming of thecar, adding a touch of color.

how they

Awning for Your GarageTHE intense heat while working in

a private garage during the hotmonths and unhealthy fumes from run-ning the engine may be avoided byequipping the garage with a largeawning. Oiling, greasing, and adjust-ing may be done under this awning.

AWNINGFULL WIDTH

FRONT

PORCH TYPE OF AWNINGON PRIVATE GARAGE

SIDE

Awning installed on the front of the garage.

This is a distinct advantage for wash-ing the car in the open as the sun willnot beat down on the car and cause un-even, streaky drying. An awning ofthe same colors as those used on thehome adds to the completeness andattractiveness of the surroundings.

Stethoscope Spots Engine NoisesRIVETED

DIAPHRAGM

TELEPHONERECEIVER

HARDRUBBERBUSHING

I DRILL ROD8 ,_....,

r---..4.---SHARP POINT

Stethoscope for locating engine noises.

AVERY sensitive form of a stetho-scope can be made from the ear

piece of a telephone reconstructed asshown. The electrical parts of the re-ceiver are discarded, and in place ofthis a small steel rod, aboutone-eighthinch in diameter and eighteen incheslong, is secured to the metal diaphragm,by riveting. The detecting end of therod is led through a hard rubber plugat the end of the ear piece. The rodend is made sharp or pointed so as topenetrate paint and grease. Care shouldbe taken not to allow the rod to be bent.

Fixing Broken Door Handle

;111111111

Diagram showing how door handle wasrepaired.

ABROKEN handle on a closed carmay be repaired as follows : Saw

off a short length ,of threaded stem of atire valve. Obtain two nickel -platedvalve dust caps. File out the hole inthe door handle knob slightly to accom-modate the threaded stem. The dustcaps are screwed on each side to com-plete the repair. This improvised handlemakes a good emergency repair job, butit will serve the further life of the carif desired.


HOME MOVIESHow Filters and New Color Attachment Enable You to

Capture True Color Values

By Don BennettMEDIUM GREEN

ORANGE

NEUTRAL

BAKELITE

DARK GREEN

YELLOW

LIGHT GREEN

LIGHT AMBER

LIGHT RED

LIGHT GREEN

LIGHT RED

NEUTRAL

-FLICKERBLADE"

GREEN

D0 you recall those snapshotsyou have made of beauti fulautumnal foliage, a veritable

riot of color, and the prints showedonly a mass of gray or black, with nodistinction between the shades or thecolors?

Would you like similar picturesthat showed every little gradation oftone, the gradations between parts ofa single leaf even, parts that varyfrom green to red, with all the shadesbetween? Even though your picturesare still black and white, thereforemonotone, you can have gradation ofthat monotone that will give you abeautiful scene.

Of course, for those amateurs for-tunate enough to have color equipmenton their movie cameras, autumn pre-sents an opportunity out of the reachof the "still" man, unless he possesseselaborate equipment and experiencefor the making of color plates, and heis not always sure of his re-sults.

George Blake, advisor -at -large to the Rockland MovieClubs, was asked to deliver atalk on capturing colors inblack and white:

"The prime necessity in get-ting true color value is pan-chromatic film. The use of thisfilm with the proper filters as-sures as nearly a correct ren-dition of color in monotone asis possible. Anelaborate set offilters is notnecessary. Someamateurs makeout with onlyone filter, grad-uated in densityfrom zero to afactor of aboutthree times.These filters

SPRING CLAMP

The most com-mon type of filter

in use.

Vitacolor camerafilter, which you at-tach to the mo v iecamera when takingpictures that are tobe reproduced in

color.

L

No alterationsmovie projector

add a

Taking pictures on a homemovie camera with the Vita -color filter. The colorfilter adds little weightand is so compact thatit does not interferewith the easy operation.

are made in the hometo show colors, except tol'itacolor filter.

FRONT REAR

Graduated filter and holder whichfits over the lens of the camera.

CLAMP (SPRING)

FRONT REAR

Holder for square filters. The springclamp fits over the lens and filters slide

in the frame.

come in various densities, and the sec-ond grade is a good filter for all-roundoutdoor work. This provides a rangeas specified above and is equivalent tothe plain filters up to K2. For specialeffects, other filters may be used ; there

Standard homemovie projector

with the Pitacolor projector filter at-tached. Without this filter attached, thepictures would appear like any ordinarypictures in black and white. The new4--a& filter adds the color.

The projector filter is like the cameraj. ter, except that the colors are arranged

differently.

DARK BLUE

GREEN

BAKELITE-,

DARK RED

BLUE

GREEN._L_

YELLOW

GREEN

N - 7 NEUTRALUGHT BLuE

ti.l_ __,,a NEUTRAL

DARK RED

are almost four hundred to choosefrom.

"Perhaps an explanation of the filter factor isdesirable. These factors, always given with a filteror in the catalog of the manufacturer, refer to theincrease over normal exposure that must be givenwhen the filter is used. For example: your expo-sure meter calls for an exposure of f11. You de-cide to use a 2x filter, requiring double the exposure.Doubling f11, we get f8, the proper exposure witha 2x filter."

"Mr. Blake, why do you say f8 is double theexposure of fll?"

"Because every stop is approximately twice theexposure of the next smaller stop. The rule is, that the rela-tion between stop numbers shall be inversely proportionateto their squares. If we square 11 we get 121, and the squareof 8 is 64, approximately half but photographically twice aslarge. It is safe to assume that every stop mark on yourlens represents twice the exposure of the mark next highernumerically."

"What would the correct exposure with a 4x filter be, Mr.Blake?"

"For a 4x filter we would again double, getting f5.6. Thesquare of 5.6 is 31.36, which is nearly half of 64. If thefilter factor were three instead of four, we would have thedifference between the two, f8 and f5.6, and our exposurewould be in the neighborhood of f6.3.

"For convenience, I will give you the stops from thesmallest to the largest with the squares so that the relationis apparent : For the amateur movie enthusiast who reallywants to get the best photographic results possible, it ishighly essential that he thoroughly understand this matter."

(Continued on page 567)


Thev:as

Repairing WoodenClock WorksBy

Samuel Bernard

\old clock movement shown above is made en/I, ty of wood andrepaired by using a preparation which when thoroughly dry

resembles wood. This compound can be used for making all sortsof repairs on wooden objects. The writer repaired the clock with

this plastic wood which can be molded easily.

New "Wood" Used for Mending Old Movements

THIS old clock movement, madeof wood-the wheels, the plates,the whole "works"-has been

ticking off the minutes in Americanhistory since the days of Adams andJefferson and Hamilton. The teethof a couple of wheels, and the leavesof a couple of pinions were brokenoff. The owner of this clock wasanxious to have it repaired-it washis family heirloom for more thanfour generations. But every watch-maker in New York to whom hebrought the clock for repairs turnedhim down-they did not want to"fool" with it. None of them evi-dently knows that there is a sort ofplastic wood that is an invaluable aidin repairing and strengthening woodof every description, and that holdsequally true with the old woodenclock.

During the early development ofdevices for telling time, there wereclockmakers developed from priests,blacksmiths and locksmiths. A lock-smith, by the way, Peter Heinlein,invented the first watch. He madeit possible by substituting a coiled1 mainspring to drive the geared mech-anism, and thus discarding the brickor stone they used for motive power.

In the early days of American his-tory, when wood was plentiful, and the carpenter was thegeneral mechanic, and who had frequently to make cases forclock movements imported from England or Holland, quite afew highly skilled carpenters set out to make clocks out ofwood. (Continued on page 555)

How to Have Talking Movies.IT is altogether

possible forh o in e movie -

makers to producemoving pictureswhich combinetalking and a "syn-chronized" score.The system used isone that will notrequire a large out-put of money, andone that when usedproperly will givegood results bothfrom an electricaland a dramaticstandpoint.

The requiredparts, besides a mo-tion picture cameraand a projector,are as follows:

A phonograph,an electric pick-up for the same,

By SAMUEL m. LOVENSTEIN

.-"ITCH(r M*1-0 ICROPHONE

LOUD SPEAKERBEHIND SCREEN

The amateur movie -maker can synchronize his pictures with voice and music as illustratedabove. A musical score can be added to any film by merely playing the phonograph record.

A microphone can be switched in when desired.

a good radio set,a microphone withsome sort of switchor an old tele-

- phone.Attach the pick-

up to the phono-graph, and connectit to the radio setin the usual way-as recommended bythe manufacturer.Connect the micro-phone in parallelwith the pick-up ;with the switch, ifexternal, in the po-sition shown. Ofcourse, if a tele-phone is used, thereceiver hook willact as a switch toopen the "mike"circuit.

(Continued onpage 554)


A finished wooden tablelamp, complete with

shade.

THIS month we il-lustrate a group ofsmall lamps, a few

candlesticks, and twodifferent vases, any or allof which will make verywelcome additional homefurnishings. In thewriter's experience hehas never seen a homeyet where another lampcould not be used to ad-vantage. Candlesticksare always in good form,on the table or mantle,and the vases will proveto be useful as well asornamental. They make particularly Xmas gifts.

Design in table lamps, as well as other furniture and fur-nishings, is changing. A few years ago the six-foot floor

lamp, with a huge umbrella-like shade, was quite the thing.

Now we have the bridge lamp and low floor lamp, withsmaller shades to take the place of the ponderous lamp ofyears gone by. So the style has also changed in table lamps,and the newer ones are plainer, smaller, not so slender inproportion, and the wood is moreoften painted or lacquer e d thanstained.

Dimensions, excepting a few gen-eral ones, have been left off of thedrawings that accompany this article,but the scale is indicated. Before be-ginning work on any one of thesepieces, take a narrow strip of paperand lay off the scale exactly to thesize that is in the magazine article.Using this, measure each part of thedrawing and make a full-size halfsketch on a sheet of white paper, usinga soft pencil. Fold this half over andtransfer the other half by rubbing over

Home Wood TurningProvides Artistic

Lamps and CandlesticksBy H. L. Weatherby

Article No. 14 in a Series

IAORTISE FOR POST)

HOLE FOR CORD

TURN BASE ONFACE -PLATE

THREAD FOR SOCKET

TURN POST BETWEEN CENTERS

A candlestick, similar tothe one below, is easily

turned.

IIRON PIPETHROUGH POST

Various styles of wooden table lamps which are easily turnedin the lathe.

the paper back of the lines,thereby giving a full patternto work by. Measurementscan be calipered directlyfrom this pattern.

The lamps illustrated areto be constructed in twoparts, as the drawings indi-

Wooden candlesticks are particu-larly in favor nowadays, especiallyas gifts at the Christmas season.Here are suggested styles of easilyturned wood candlesticks whicheven the amateur will find quite

within the limits of his skill.

611._1I 41-1

Glue or paste feltto the bottom ofany of the articlesturned, and trimthe edges with scis-sors after it h a sdried. In manycases a lead discshould be fastenedto the base underthe felt to give sta-

bility.

7'tIt takes a glass testtube to make a vaseof this kind. Thevase is turned in

6---4' -1 the lathe by thewood - worker.Pleasure and profitcombined m a y be

realized by the wood -turner.

cate. The base should be turned froma block fastened to a face plate, whilethe post is turned between centers.A mortise is turned in the base and


fine


iAIR PIPE

3"71.- PIPE

(NIPPLE

COCK

21ic 24"

REDUCER

1 -"AIR PIPE

DEEP wells require heavypumps, powerful enginesand complicated piping

systems where regular pumpingsystems are resorted to, andthese all mean great expense andmany moving parts to care for.While probably the efficiency ofthe air lift system is not sogreat as the pump system, yetits simplicity has a certain ap-peal and the rural dweller canraise water from a considerabledepth with but little complicatedmachinery. The discharge mustbe lifted either to an overheadtank or to a sump; pressuretanks cannot be used. A fewpipe fittings, a small gas engine,a discarded stationary or motor-cycle engine, belting and a tankcapable of holding up to 100lbs. of compressed air comprise the main features of such asystem. The principle of the system is simple. It consistsmerely of forcing air down to the water and forcing thelatter up a pipe to the reservoir arranged for it. By fol-lowing the instructions, it should be possible to build such asystem for only a few dollars against a much larger pricefor a regulation pump system.

The Air Lift System

er HE system in general consists of a large diameter pipe1. extending down to the bottom of the well. Inside it issuspended a second smaller pipe connected to the air-pres-sure tank on the surface. This is filled by an air compressoroperated by the gas engine. When air is injected from the

BELTED TO ENGINE*OR MOTOR

INTAKE

SAFETY VALVEGAUGE

AIR COMPRESSOR AIR EQUALIZINGMADE OF OLD GAS ENGINE TANK

4.G ATE VALVE 43NIPPLE

q ELBOW,

24BUSHING2"FLANGED COUPLING

2"CROSS

Z"OISCHARGEPIPE

2 EDUCTION PIPE

DETAIL OFWELL HEAD

2")034.BUSHIN6

"74,- PIPE

rA, .wo

GATE VALVE

FLANGED COUPLING

DISCHARGE

EDUCTIONPIPE

Making AnAir Lift PumpThe Air Lift System for Dee')Wells Is Not Unknown, butIts Use Seems to Be Confinedto Certain Limited Sectionsof the Country. It Is Exceed-ingly Inexpensive, and OneThat a Practical Man Can

Build for HimselfBy L B. ROBBINS

tank to below the level of waterit pushes a column of water upthe larger pipe to discharge itinto the tank above. These dia-grams are drawn with the ideaof lifting water from a deep,open well. With a driven wellit will only be necessary to sub-stitute a drive point strainer forthe ball strainer shown.

The well head is the firstthing to consider. For ordinarypurposes a 2 -in. eduction pipewill be sufficient. First attachthe strainer to the eduction pipeand sink it or drive it to the re-quired depth, so a good depth ofwater stands in the pipe. At aconvenient height above groundthread on a 2 -in. cross, one sideopening to face the reservoirtank. Fit a common pressure

cock into the opposite side opening by means of a 2"X3A"bushing. Thread a 2 -in. close nipple into the top of thecross and on top of that the lower half of a 2 -in. flangecoupling. Then arrange a firm support for this eductionhead and pipe and lead a 2 -in. pipe to the tank. Of course,a check valve in this discharge line will be of advantage toprevent the supply running back into the well. Run a2"M4" bushing into the top half of the flange coupling.Place the gasket between the halves and then you are readyfor the air pipe. The foot piece must be constructed first asfollows:

Cap one end of a length of ht -in. pipe. Then, at a dis-tance above the cap, at least 3 ft. greater than the height ofthe end of the eduction pipe above the strainer top, cut 3 or4 slots for air outlets. Their (Continued on page 560)

WATER

AIR PIPE

DEEP WELL

STRAINER

LONG THREADUPPER 2"FLANGEGASKETLOWER 2 FLANGE2" PI PE111

m

DETAIL OF FLANGED CONNECTION

iAIR PIPE

2EDUCTIONPIPE

SPACERPINS

3 OR 4 AIR SLOTSTOTAL AREA EQUALTO AREA OF PIPEAND AT LEAST 3 FT.ABOVE STRAINERHOLES

CAP DETAIL OF FOOT

PIECE FOR DISCHARGING,SUFFICIENTLY LARGE AIR INTO WATERBALL oR POINT

STRAINER END PLATE ADDED TO PISTON TOAID COMPRESSION

INTAKE VALVE LEFT ON rINTAKE PIPE AND' r=777777 CARBURETOR

REMOVED &PORT LEFT'OPEN

AIR PIPETO TANK

PISTON

CHECK VALVE EXHAUST PORT CLOSED

VALVE CHANGES TO MAKE ANAIR COMPRESSOR FROM AN OLD

GAS ENGINE

Here are shown the details for building an air-lift pump for deep inner pipe, and on rising to the surface, it carries the water inwells. As will be observed, there are two pipes; one within the the outer pipe with it. In driven wells the only change necessaryother, tl4e compressed air being forced out of the open end of the is the substitution of a sufficiently large strainer at the bottom ofthe outer pipe.


New Two -Seater German GliderIdeally Suited for Training Pilots

4111111 t. g UMW-"411111 11110

f= IMP MN WWI IIM IMO Mr ON mttnst mmirfirgellamin gana 1,=Z ;

Under view of glider, showing large wing spread.

THIS glider, of the Mecklenberg type, was developed byEngineer Krekel and was constructed from the standpointof a cheap, level ground glider, which also would answer

for school purposes and for test flights at low heights with littlewind. Above all, the machine was to answer as a two-seaterand to be light, in order to have the greatest advantages of atwo -seated gliding and school plane. With regard to carryingit back to the starting point, it is necessary for a two -seatedmachine to be very light when empty.

The machine was built in the workshop of the MecklenbergAero Club, in Rostock, Germany. Especially noticeable is theunusual extensive use of thin -walled welded steel tubing inbuilding the plane. The two -seated boat is made of steel tubing,covered with fabric, and is joined to the wing by wire. Thecabane strut is also made of steel tubing. The control cables,made of flexible wire cable, are attached to a spindle, whichputs it under tension and gives a very easytime of attaching is only twenty minutes; the time of detachinglasts but 15 minutes, which is done by dropping the spindledown into the central cabane tube. The time required forfreeing the cable from the plane and attaching the plane theretois very short.

The wing is in two divisions and is made of wood, veneer andfabric with two cross -beams. The beams are made of high,narrow boards with holes sawed out on the neutral line, in orderto reduce their weight without diminishing the strength. Theribs are 1.6 inches apart. The rudder has a differential schemeof control.

The elevating plane and the rudder are made of steel tubeconstruction. The pin is made out of wood. The steering is anormal, double steering, with duraluminum joy stick. Sidesteering is carried out by pendulum action.

The central skid is of ash and is strengthened by steel tubesand has India rubber cable attachment.

The principal measurements of the machine follow. If thereader has read the article on glider construction appearing inthe June and July issues, he should find no difficulty in con-structing this machine.

The weight unloaded is 209 pounds. The width is 39.7 feet.The length is 23 feet and the height is 8 feet. The area of thesail is 226 sq. ft. The depth of the wings 6 feet. The ratio ofthe sides 1 :68.

Several views of the Mecklenberg glider, giving agood idea of its general design. The diagram atthe left gives some idea of the rib construction and

fuselage suspension.

AIMMININIkw

_ _

fl

/

' 197'

Plans of Mecklenberg

T

tr.

T "

41111r._

glider, giving dimensions.

I

The two pictures below show a single -seated glider of theMecklenberg type that is manufactured in the United Statesand which sells for a very reasonable price. The pilot,a former German glider enthusiast, is ready to test the

machine.


COFFEE

CAN

SOCKETS

WOOD BLOCK

DISK OF BAKELITE

RED

CELLULOID

SLOTFORSHIELD

GREEN

CELLULOID

2 POINTS ABAFT THE BEAM

OPENINGS IN CAN

PAINTED OR ENAMELED

SUITABLE COLOR

RED

LUG I" PARTITION

FINISHED BOW LIGHT

Running Lights for Small BoatsNY small boat owner can build a set of port and star-

board running lights, at very little expense. and theywill be found to be serviceable in fair weather or foul. Thecovers for the lights are made from coffee cans, or anyclean can the right size.

Match BoxUsed as

MeasuringTool

ASMALL safe-ty match box

forms a convenienttool for measuringsmall distances andopenings. If thedistance is short.lay the box down

and slide the tray out to the limits desired. Mark the dimen-sion with a pencil on the side of the tray. against the edgeof the box. If the distance is greater than the tray andbox, take the length of the box first as part of the measure-ment, laying it down again and sliding the tray out to getthe distance accurately. The distances may be comparedwith a rule if necessary.-L. B. Robbins.

How toTangle -lessIron Cord

DUBBER bandslooped together

to form a chainabout two feet longmake a simple helpfor ironing day.The free ends ofthe chain are at-tached to the ironcord and plug withpieces of string.This arrangementis applicable toother electrical ap-pliances. - IV. E.Burton.

BRACE

JOINT

FIG.I

SPLITTING 4.SPLICED

BAMBOO JOINTrSPLIT BAMBOO FRAME WITH HACK SAW I I

OLD BROOM HANDLE 4. -6 -LONG RING &SCREW EYE

SLAT

CANVAS

SAIL

BEAM

HIGH

- LBR00M HANDLEBEAML SCREW EYES

FIG.2

Constructional details of the two sails andthe method of using them.

TUBE MADE OF PAPERGLUED AROUND A ROD

CARDBOARDRUDDER 1x21 -x3"

2

PATTERN FOR ALUMINUMPROPELLER

4"

- SQHOLEWIRE SHAFTGLASS BEADS

CORK FOR FRONT END

ASSEMBLY OF

THE SHOOTING ARROW

THIN SHEET\ ALUMINUM \PROPELLER

Ice SailingHints

TT'S fun to sail1 on the ice ! Hereare the construc-tional details oftwo types of icesails to be usedwith ice skates.The triangular sailmay be constructedso that it can berolled up, but thecircular sail islighter, more rigid.and more effectivebecause of itsgreater area ex-posed to the wind.The bamboo shouldbe soaked a fewhours to make itpliable.-D. R. l'anHorn.

A Toy Helicopter

ATOY that will rise fifty feet ormore over the spot from Where it

was launched can be quickly and easilyconstructed from readily obtainable parts.The construction of the propeller is im-portant. Care should be taken to see thatthe two blades are balanced. The wholehelicopter may be lightened by using acelluloid propeller. The toy will thenrise much higher on the same power.The power depends on the rubber band.From fifty to a hundred turns can usu-ally be made in winding the propellerwith an ordinary rubber band. A strongerband will permit a proportionately greaternumber of turns and the toy helicopterwill go higher into the air. They havebeen known to rise as high as 1z0 feet.The aviation student may well experi-ment with helicopter models, for the verygood reason that the future aircraft willundoubtedly be based on the helicopterprinciple.-D. R. l'on Horn.


Make It!Plastic Objects from Paper

PLASTIC objects can he made from paper so that theyresemble ornamental details made from plaster of Paris,

metal or even wooden carvings. These plastics from paperway be painted, varnished or. in fact, treated any way de-sired by the maker.-Dr. E. Bade.

..162411121Each sheet is pressed in separately and the whole is dried underpressure. When dry, the protruding edges may be cut as desired.

PIPE INCLINED UPWARD IF RUN TO BATHROOM

GLOBE

VALVE

FORCE

PUMP

NOT OVER

22 FT.

HOT WATER

TANK

STOVE

.L. DRAW OFF

tWELL OR PUMP STRAINER

PUMP IS USED FOR BOTH

HOT AND COLD WATER

Optical IllusionsTHE disks in No. 1 begin to turn when

the page is moved in a circular mo-tion. Spin No. 2 over black type and itwill appear red. In No. 3 white linestransverse the black letters, but appear ascontinuous white lines. Which is longerin No. 4? 1-2 or 3-4? Spin the diskin No. 5. The outer parts appear blueand the inner portion red. The "MonkeyTail" in No. 6 is made up of true portionsof circles of varying diameters. Severalinteresting effects may be noticed. Thoseinterested in optical illusions xyill findmany other surprising illusions describedin books to be found in their home orlocal libraries-D. R. V.

Hot Water forthe Farm

AHOT-WATERsystem *that

may be used whererunning water isnot available isshown. The forcepump supplies hotw a t e r as neededf r o m the reservetank, at the samet i m e replenishingthe water to beheated.-L. B.Robbins.

W

Moist sheets of paper are placed over the mold. Dilute glue isspread between each layer. Sufficient paper is put on to fill the

cavities.

Amusing ToyWindmills

WHY. not makeyour next

toy windmill onethat gives someamusing action?The diagram showsan Indian that pad-dles his own canoe.The blade of thepropeller a c t s asthe paddle. Theparts are madef r o in heavy gal-vanized sheet iron.The design isdrawn on paperand then traced onthe iron xvith trac-ing paper. Thewhole is painted tosuit. Many otheramusing arrange-ment s may beworked out with alittle thoug-ht.-D.I?. ran Horn.

ORANGE

BROWN

FRONT VIEW

VANE

YELLOW

RED

BLACK

BRASS TUBE WITHWIRE SHAFTRUNNING THRU

SOLDER

SCREW &:WASHER

x -SUPPORT

PADDLES OF TIN S "x 1;(41

CANOE II "LONG

Constructional details for the windmill.The effect is Mat of the Indian paddling.

THE SPINNING WHEEL

THE RAINBOW TOP

!! ! ! !-' if -M

TO SHOW BLACK RED

THE MONKEY TAIL

i_ a_

IMAGINARY LINES

/7- -\3 4

THE BOAT ILLUSION


Hints for the Home Work-VIM

"1"ralizall1111111

, */10104001.100404.Nie Iii

Knives made from hack saw blades. Thelarger knives are made from power hack

saw blades.

the rough scratches of the emery wheelif these marks are objectionable.

Good handles for these knives can bemade from leather or wood. The steelshould be softened at the handle part inorder to permit holes to be drilled for thehandle. This is done by heating thatpart to redness and allowing it to coolvery slowly.-R. B. Wailes.

Flexible Shafts for WorkingModels

DRIVENSHAFT

DRIVERSHAFT

-11-1',11111111111111kAiN

ANCHOR- M ir"!SPRING

Knives FromHack SawsSERVICE-

ABLE knivescan be made frombroken hack sawblades. The bladeshould be grounddown to the par-ticular style de-sired on an emerywheel. Careshould be takennot to allow theblade to becometoo hot whengrinding. Keepthe blade cool bydipping into waterwhile beingground. Aftergrinding, fine em-ery powder andwater will removeany dulness, and

IRON STRAP

Repairing the BraceACARPENTER'S bracewith a loose knob may

be repaired as shown. Drill3/16" holes for yi" stovebolts and countersink for theheads of the bolts. File theends of the bolts to a pointso that they will fit the threadafter the knob is in place.Stagger the holes, one a littlehigher than the other to per-mit each bolt to catch a dif-ferent thread. After the holesare drilled, screw in the boltsuntil they just show through,then screw on the knob. Thewhole may then be tightenedby screwing the bolts in tighter. Many a carpenter's bracehas been discarded after a long and hard usage. This ar-rangement will permit these tools to be resurrected and againput into service. Braces fixed in this way have been knownto serve their owners for many useful years.-A. I'. Kelly.

PRESSURE EXERTED

STEEL PLATE

WOOD LEVER

PIECE TO BE DRILLED

ikSHORTlength of

steel spring makesexcellent flexibleshafting for modelmachinery. It canoften be used toCOIL SPRING.advantage in the

place of belting and gearing. An ordinary screen doorspring can often be employed. The two regular sizes fittightly on 3/16" and 1/4" solid shafts, the diameters mostcommon on small motors and machines. The spring issimply forced onto the end of the shaft with a twistingmotion. In making turns, a radius of about six to eighttimes the shaft diameter is most satisfactory, usually, andruns without twisting and kinking.-R. Le Conzpte.

BLOCKOF IRON

Cutting a Left -HandBOLT Thread Without a Lathe

ALEFT-HAND threadcan readily be cut with-

out a lathe by drilling twoholes in a block of iron thesame size as the bolt to bethreaded. One of the holesshould be drilled slanted toenable the tap to cut on thebolt. The thread is cut on thebolt by turning to the left.-J. Grand.

Handy Portable Motor LeverIN order to bring sufficient pressure

upon a portable drill for rapid workan improvised pressure lever may be de-vised. The lever shown was made froma steel strap 1Y2 X h". It was bentover a strong wooden lever, and boltedto the same. One end of the strap wascurved to tit over the bottom flange ofthe channel iron, while the other wasmade to fit the top one. A steel platewas bolted to the under side of thewooden lever to hold the pivot of themotor. This arrangement will be founduseful whenever it is impractical to do the work at a drillpress.-J. Coyle.

Sensitive Calipers

SOLDERED

CROSS SECTION OF WORK

RADIO BATTERY

ASIMPLE arrangement for making a pair of caliperssensitive for precise measurements is shown above.

The contact point should be insulated from the leg of thecalipers on which it is fastened.-E. J. Pratt.

Welding Aid

PIECESof iron

may be held inplace for weldingby using electro-magnets. Theparts are spot-welded first, andthe welding iscompleted afterthe magnets areremoved.

ELECTRO MAGNETIC COILS

Fag.'r41111111 I II

!lg. 3

L; OINTS TO BE WELDED


ShopSmall Portable Grinder

First Prize $10.00ASMALL grinder that has many

uses around the shop and for the'home mechanic can be easily constructedfor less than three dollars. exclusive ofthe motor. This grinder is handy forgrinding small bushings, cylinders, pinsand lathe centers. It can also be fas-tened in a vise and used to sharpenknives, tools and (rills.

There are two pieces to he made toattach to the motor. Figures 4 and 15show the support which is held fast bythe tool post and vise. This should bemade of good material such as tool steel.The saddle is shown in figures 2. 12 and13. It is attached, as shown. to themotor. At figures 16 and 17 is the ad-justing bolt for the saddle and arm.The shaft on the motor shown in figure6 has a thread cut as shown. The sidecollars at 10 and 11 are made accordingto the size of the wheel to be used.Collar 11 is threaded and attached as at

0-

kp,

Constructional details of the grinder. The dimensions depend on the size of the motor.

figure 8. Collar 10 is not threaded.See 1.) The nut to hold the wheel

tight is shown at 9.A wheel about two inches in diameter

Doing a Large Job on a Small LatheWHEN a piece of

work has to bedone that is too large forthe lathe at hand, it is agood idea to have somemeans by which the workmay be done withoutsending it out to a shopwith larger equipment.It is possible to rig up thesmall lathe so that thejob may be turned on it.

First a spindle is

OLD LATHE BED

SLIDEREST

An old lathe bed is fastenedto the end of the lathe and

the tool rest run on it.

BRASSBUSH

JOB

BELT TO BE CROSSED

OF

LATHE

/THREADED TO FIT SELFCENTERING CHUCK.

COLLAR TO FIT BRASSBUSH ON LATHE END

The spindle and its arrangement in the lathe, shavinghow the large piece of work is fastened to the bead.

turned to fit through the hollow lathe mandrel. Itis threaded at one end to take the chuck. A collaris made to fit the brass hushing at the lathe end.The spindle is then putthrough the lathe mandreland the plain end is grippedin the chuck. The back headis brought up to the centre inthe spindle end to take theweight and to prevent chatter.

A chuck is then screwed onthe spindle end at the back ofthe lathe, and the job, whichis previously drilled and

pressed on to a mandrel, is placed in the chuck.An old piece of the bed of an old lathe is then placed

across the end of the lathe with the lathe rest attached.The job is then turned as far as the limit of the rest. Therest is then moved further along the bed.

In order to make the head turn in the proper direction,where no reversing arrangement is on the lathe. the belt iscrossed. The head will then turn in the opposite direction.

This arrangement will be found to be useful for theoccasional large piece of work and will obviate the neces-sity of buying a larger lathe.-II'. H. Conley.

works best on a small grinder of thistype.

Almost every shop has a small motorsuitable for a grinder of this type. Hereis a chance to make good use of it.-E. McDonald.

Hole Boring KinkPTO eliminate splitting when boring1 holes near the end of a piece of

wood. bore the hole through work firstand then saw to the right length.-R. Wailes.

Bench Grinder Made From Auto PistonAUSEFUL bench grinder may be made from a discarded

auto piston as shown. A snug -fitting rod or bolt isinserted in the wrist -pin. The shaft is kept from turningin the wrist -pin by grinding notches in the ends of the pinand inserting rivets in holes drilled through the shaft.-E. Thaddeus.

SHAFT BUSHING

WOODPULLEYPISTON

GREASE GRINDINGCUPS WHEEL

WRISTPIN

PIN

Irow,'

WASHERS777

BENCHs

SPACINGWASHER

Useful bench grinder made from old piston.


For Those Who "RollOwn"

THE small spring from an old tirevalve core worked over the band

around the usual book of cigarettepapers makes it easier to slip off theband.-F. Bentley, Jr.

Their

Paint Spray OutfitikHANDY paint spray outfit may

I is a weight which maintains a con-stant pressure in the inner tube so thateven spraying results.-F. H. Carl berg.

441, i '4)

Improvised HandleAN emergency handle for a cover or

door can be made with four nailsand some heavy cord or wire. A goodgrip results.-F. Bentley, Jr.

A Shop StoveTHIS stove is constructed of a four -

foot section of a steel smokestack.A few pieces of scrap lumber dropped

into a stove likethis will keepthe shop warmfor half a day.Draft is regu-lated by a damp-er in the pipe andby replacing abrick in the base.The stove shouldnot be placed ona wooden floorwithout properinsulation. - A.Wilson.

-PIPEDAMPERHINGE

COVER

CTIONOF

SMOKE-STACK

BRICKREMOVED

FORDRAFT

BRICKBASE

WRINKLESSimple Method for Making Cel-

luloid CementIn proportional amounts dissolve 5

square inches of sheet celluloid in aboutY2 oz. of lacquer or Duco thinner. Forbest results this mixture should be in atightly corked bottle and in a warmplace. This will make a syrup-like solu-tion, which can be diluted by addingmore thinner or made thicker by evapo-ration.

Celluloid drafting triangles and cellu-loid -edged scales and rulers often getchipped or cracked, making them use-less. These can be repaired nicely, asshown in drawings previously. Athick solution, as described above, isused.

Celluloid clock cases, celluloid fin-ished articles, auto side curtains canbe repaired by using a thick solution ofcollodion, and watch crystals whichhave become loose may be secured inplace by using this solution like glue.The SCIENCE AND INVENTION ReporterCard may be made more durable bymounting it between two sheets of cellu-loid and using the thick solution as anadhesive. The small ruler printed onpage 1122 of the April issue of thismagazine may also be made serviceableby mounting in the same manner.

A light, clear solution of celluloidcan be made into a beautiful transparentpaint by adding colored liquid clothing(lye, which can be bought in mostdepartment stores. By varying theamounts of dye and mixing the colorsalmost any color or shade can be ob-tained. This paint is very desirable forpainting on glass, coloring lanternslides and films, decorating lamp shades,coloring plain electric light bulbs andfor coloring drawings where certaindetails are to remain visible.

By spraying charcoal or pencilsketches with a light solution of clearcelluloid the lines will remain fixed andwill not smear nor affect the appearanceof the drawing. By using a thicker so-lution sketches, paintings, etc., may bemade glossy and waterproof.

Another service to which this for-mula may be put is as an anti -blot.A fairly thin solution is poured orsprayed over an erasure on a drawingand allowed to dry after all surplus hasbeen wiped off. Corrections can bemade over the treated spot without fearof the ink blotting or running. Porouspaper and even blotting paper may bedrawn on after treating with this solu-tion.-Contributcd by E. R. Vass.

Supports for Lamp CordSmall brass hooks screwed in the

baseboard near the top and spaced every2 to 3 ft. make a neat and convenientmeans for holding the flexible wirefrom that floor lamp. Tying the wireto the hooks with thread or string tomatch the color of the insulation alsoadds to the appearance. Pull the wiretaut before tying.-Edinund Mills.

b HOLES

FM2

STRIP BRASS

MEEz1--IFAHNESTOCK

CLIP

TWO STRIPS REQUIRED FOR PARALLEL

CONNECTION OF THREE DRY CELLS

It -HOLE - TWO STRIPS LIKE

BRASS STRIPTHIS FOR SERIES

CONNECTION OF

3 DRY CELLS

Quick Battery ConnectorsFOR the electrical experimenter or

worker a quick method of hookingup dry cells in either series or parallelis a labor-saving device. It can also beused permanently and will be foundhandy and neat.-L. B. Robbins.

NOTCH

Handy Bottle -Cap LifterACOMMON pocket knife may be

made into a convenient bottle -toplifter by filing a small notch in the heelof the blade. This increases the ser-viceability of your knife and does notinterfere with its ordinary use. -1'.Johnson.

Substitute "U" TackWHEN it is necessary to fasten in-

sulated battery wires, commonbrass safety chain can well be used.Open the link and close it with roundportion over the wire. Drive a tackthrough the two rectangular holes, clos-ing the link snugly over the wire andfastening it down.

This makes a cheap and attractivefastener that will not rust. It is easierto install wiring with this method thanwith the regular "U" tacks.-F. Bent-ley, Jr.


and RECIPESMEDICINE DROPPER

POT.BICHROMATEAND DIL.HNO3

'SILVER" SPOONUNDER TEST

NO STAIN -NO SILVER.

RED STAIN- SILVE

Is Your Silver Real?YOU may test your silver plate and

solid silver for purity by applyinga small drop of a solution of PotassiumBichromate in dilute Nitric Acid. where-upon real silver, whether plate orsolid, will give a red stain of silverchromate. Be sure to 'wash off thesolution immediately. The mixture ismade from a saturated solution of Bi-chromate with one-half its volume ofconcentrated Nitric Acid added.-D. Harris.

"Breaking In" Your PipeGENTLEMEN pipe smokers, here

is a way to avoid that varnishtaste of a new pipe. The pipe is filled,lighted, and placed before an electricfan. If you have no electric fan handy,try putting in a draft like that from awindow. In about fifteen or twentyminutes you can clean out the pipe andrefill it.-E. Moen.

CUTBINDERS

A New BroomBROOMS wear down unevenly, mak-

ing their life short. When thesplints wear down so short that it isdifficult to sweep. it is a good idea tocut out some of the binders, increasingthe effective length of the splints. Thebottom should be squared.-J. Ketchpel.

Good Service from Safety RazorBlades

A man who always has a smooth,clean shave gave us some tips he haslearned about the care of a safety razor.And incidentally he gets double and evenmore than double service out of hisblades. Cleanliness to prevent rust andvery hot water is the secret of his suc-cess!

He always uses hot water on theblade when through shaving, and whileshaving, as it dries the razor quicklyand thoroughly, leaving no moisture tomake rust and a dull edge. After ashave, he removes the blade and washesthe holder in hot water too, drying care-fully before putting the blade back.

After the blade is thoroughly washedunder a stream of hot water, he wipesit with a rough towel, toward the edgeof the blade, thus using the towel as asort of strop. Simple, it seems, but veryeffective as experience has shown.-T.B. Brownfield.

Cutting String BeansMuch time will be saved in cutting up

string beans by grouping a number ofthem in one hand, placing them on thebread board and slicing them simultane-ously.-Contributed by Edmund Mills.

A Simple InkAn excellent ink is made by dis-

solving the lead from a copying pencilin a cup of water. This pencil can bedistinguished from other pencils by theword "copying" on it.-S. J. Weicher.

Simple RheostatAn idea that will probably prove use-

ful to many readers is to use a "Dim-A-Lite" current -reducing socket tocontrol a motor, transformer, etc. Thesocket comes with a chain switch andreally works well. There are about4 steps of voltage and for a cheappower rheostat is hard to beat.-SimonCherry.

An Acid Test for Steel and IronFile, or grind, the pieces to be tested

and polish them smooth, then place themin a dilute nitric or sulphuric acidsolution for a day. Wash and dry thepieces, and if they are of the beststeel, the surface will have a frostyappearance. Ordinary steel will havea honeycomb surface, and iron willpresent a fibrous structure runningparallel to the direction in which themetal was worked.-August Jeffers.

Mending Rip in ClothHere is an excellent method of mend-

ing a cut or tear in clothing : Take apiece of adhesive plaster and cut it tothe right size. Apply it to the left sideof the cloth where it is damaged, andpress firmly with the fingers. The clothshould be on a smooth surface while theplaster is applied. The rip will bepractically invisible.-Frank Schmulo-witz.

WOODEN BOX 10 WATT

USED AS , CARBON LAMPCARRYINGCASE

Alternating Current IndicatorATEN -WATT carbon lamp and a

permanent magnet make a goodalternating current indicator. When thecurrent is on, if the filament vibrates,the current is alternating. On directcurrent the filament simply bends to oneside.-F. A. Ferri.

Impersonator. CardsACARD fixed up like the one above

will afford lots of fun for the eve-ning party. Many funny faces can bemade with the cord.-D. R. Van Horn.

An Automatic PipetteTHE pipette is filled by

suction until the liquidoverflows into D. Therubber tubing is then com-pressed when it will beobserved that the level ofthe liquid falls somewhatbelow the graduation mark.When the mouthpiece isclosed with the forefingerin the usual manner, theliquid rises again andoverflows once more. Thepipette now held by themouthpiece only is raisedout of the liquid and thecontents delivered into thereceiving vessel. W h e n.trap D is filled. rubber tub-ing and mouthpiece are re-moved and the liquid ispour e d out. Thus thepipette work s automati-cally.-F. Piontkowski.


Readers' Opinions and CommentsWill Be Welcomed by the Editors

How the Pyramids Were BuiltEditor, SCIENCE AND INVENTIN :

Reading the May issue of your maga-zine, you ran an article by J. H. Kraus,on "Ancient Versus Modern Wonders," onpages 20, 21-22, 23, 84 and 85 inclusive.The article on the "Pyramids of Gishe"and how built interested me most. Hereis my conception.

Were the stones for the pyramidsbrought to their present location by

ships and dumped over the sides?

It was more of a navigation feat thanan engineering feat. It also may be bornein mind that the pyramids are built at themouth of the River Nile, on one side ofthe bank. Since the Nile River overflowedits banks annually, it left a vast amountof detritus near its mouth.

The engineers let the detritus, mud andsand, pile up against some barriers, orsand dunes, provided for this.

After the waters receded, the mud wascollected and built up in the shape of acircle, forming a dam.

The torrid sun baked the mud and sand,and formed a strong wall like masonry.

The inside of this vast circle was thenfitted with special holes to take in water.The second year the river again overflowedand deposited more mud and driftwoodagainst this huge dam. After the watersagain receded, the work was begun. Box-.like boats were filled with water to thesinking point, then were drifted or towednear this huge circular dam. Fitted againstthe holes provided for this, they filled itto its first stage by emptying the contentsof the boats on the outside. Then themany boats inside this vast circular damwere raised to a certain stage, in much thesame principle as our own Panama Canal.Now these boats contained numerousblocks of stone for the pyramids. Thestones were rolled overboard into theirposition. Then another stage, some morewater was let in by boats on the outside,raising the boats on the inside; then thesecond stage. Stone rolled overboard intoposition, same as before.

This continued until the pyramids werebuilt, all in a short time, two years. Notmuch man power, or time, but a cleverway of harnessing the river, the wind,leverage, and navigation.

As the pyramids were "sunk" into place,before the next annual flood, the waterwas let out slowly, so as to wash awaythe entire circular dam, letting the manyempty boats on the inside flow out andinto midstream of the River Nile. Thenext annual flood (third year), practically

What Ourall the remains of the once huge circulardam were washed away, leaving the pyra-mids standing.

This is a logical conception, not touchingmuch on engineering, but on irrigation andnavigation, and not entailing much me-chanics, or machinery.

The bigger question is not how the pyra-mids were built, but how the huge stoneswere quarried up state and cut. Let'shave your opinion.

P. HILLBERG,Cincinnati, Ohio.

(Assuming that what you claim is cor-rect, how do you account for the mathe-matical position by which the interior ofthe pyramids was laid out? It is quiteevident that if stones were dropped over-board, they could not produce the passageand room found in the pyramid. It isscarcely likely that these rooms were builtup after a solid wall of stone had been putin place. If enough man -power werepresent to build the pyramids, it is quitelikely that that same man -power was ableto quarry the stones.

The cutting of those stones is a difficultquestion to decide upon. Perhaps theywere chopped up in huge blocks anddragged along the surface of other roughstones which smoothed them down. Ofcourse, this is all conjecture and your guessmight be equally as good as ours.-EDITOR.)

Space, Time and Relativity

Editor, SCIENCE AND INVENTION :

In your iSSue of SCIENCE AND INVENTIONfor April of this year, under the heading,"Space, Time and Relativity," by Dr.Menzel, page 1199, appeared the follow -

What will one see if he gets to thevery end of Einstein's limit of spaceand looks into the distance beyond?

ing: "Einstein, however, says 'no': theninety-sixth circle would be the last onethat can be drawn in our universe; . . .

after five hundred billion years, we shouldreturn to our starting point. The universeis, therefore, finite."

Now, while granting that Dr. Menzelis correct, and also that Einstein's theorymay be correct, I would much appreciate itif you could enlighten me-briefly-as tohow Einstein arrives at such a supposition,and also as "the universe" evidently in-cludes all space, what does Einstein sup-pose to be without this "ninety-sixthcircle."

While I am quite prepared to believethat, "by no possible method can we dis-

tinguish between the arc of one of thesehuge circles and our ideal straight line,"and also that it may not 'be possible forus to travel (theoretically) in anystraighter line than along this arc ; I quitefail to see how this is any argument thatthere is nothing without this circle, andanyhow, if that were so, how far doesnothing extend?

Am afraid that this letter will be ratherbelated in reaching you, but hope to seean answer in your publication a couple ofmonths hence.

Have been a reader of SCIENCE ANDINVENTION for about two years now andconsider it an excellent publication forfurthering one's general scientific edu-cation. D. A. RoomsoN,

Warburton, Victoria, Australia.

(Perhaps some of our reader supportersof Einstein's theory will give us some in-formation regarding what is beyond space.

We merely cite Einstein. We do notprofess to agree with him or his theoryin its entirety.-Editor.)

Insect Cradle BuildersEditor, SCIENCE AND INVENTION :

"Insect Cradle Builders" by Dr. ErnestBade most interesting-eagerly awaitingmore such articles.

A. H. Biss,Monte Carlo.

(Thank you and we will try to have Dr.Bade give us more articles on similar sub -j ects.-EnrroE.)

Spiritism

Editor, SCIENCE AND INVENTION:I was reading an article in an Indian-

apolis paper to the effect that your concernwas offering a prize of some $23,000 toanyone who can prove that Spiritisth orSpiritualism or Clairaudient Phenomenaor the like supernatural phenomena wereactual facts. I have not the article at handand do not remember the exact wordingbut I remember that a certain man at-tempted to give an exhibition of this sortof thing and failed to win the prize, thathe commanded a table to come to him andit refused to do so, so goes the article.I don't suppose any man living can makeinanimate objects walk from place to place.

What is required in order to win thisprize that you offer? I am not any sortof a spiritualist or dabbler in this sortof thing. I am an engineer and draftsman,

The table did not move toward thespiritualist, but merely rocked up anddown, in an attempt to answer ques-

tions.

October, 1929 Science and Invention 53:;

Readers Thinkand am interested in invention and patentsand patent practice, and also in homebuilding. I don't call myself a scientist butI am interested in scientific matters, whichyou are also or you would not be investi-gating this subject.

L. L. MEAD, Carlinville, Ill.

(The newspaper clipping which you readprobably garbled the facts considerably.SCIENCE AND INVENTION magazine has aprize contest of $21,000 for genuine spiritmanifestations of any nature. Prize con-ditions for this award have been repeatedlypublished in SCIENCE AND INVENTION maga-zine, and are also found in the introductionto the book "Spirit Exposes."

The man that appeared as a contestantfor this prize recently, did not cause atable to move. After four men were seatedat the table, the table was tipped and thenwas made to rap signals on the floor, indi-cating by the number of raps the letter inthe alphabet to which it apparently re-ferred. Actually, the effect is purely sub-conscious, but believers in spiritualism donot hold the same viewpoint which we hold.Results were void.-EDITOR.)

Handwriting Reveals Character?Editor, SCIENCE AND INVENTION:

I have been a reader of the SCIENCE ANDINVENTION for years but I have never seensuch "stuff" as this before.

What's the Grand Idea???On page 1215 of the SCIENCE AND IN-

VENTION for April 1929 you may read thefollowing :

"YOUR HANDWRITING indicates yourcharacter."

Now I doubt very much if anyone'shandwriting "indicates" their character, orever will. This person gives you a "samplereading" for the small sum of twelve cents.But I doubt if it is worth so much.

Just below this "ad -let" another reads:"LET ME READ YOUR CHARACTER."

Send birth date and twelve cents."They must have their conventional 12

cents first.I wonder what makes them think that

HANDWRITING indicates a person'scharacter.

I also wonder why you must send yourBirth Date to the sponsor of "ad -let" innumber two.

On page 1214 of the same issue I readthe following :

Objectionable or misleading adver-tisements not accepted.

Can a handwriting expert actually re-veal one's character? The answer of

the editor is an emphatic "no,"

Now exactly what does this mean?All this puzzles me because on page

Questions and Discussions ofGeneral Scientific Interest

1140 of SCIENCE AND INVENTION, April1928, I read this:

"We do not believe in graphology."Etc....The comment ends with this statement

by the editor.. . . "No, there is nothingin graphology." Did the editor meanthat???

Cordially yours,R. W. R.

Hollywood, California.

(The editor certainly did and stilldoes imply that there is nothing in graph-ology ! We do not think that you will findthese same "ads" now appearing.-Editor.)

A Trusted Test

Does the Wasserman test actually tellthe quality of the blood? For whatother diseases is it specific besides the

one well known?

Editor, SCIENCE AND INVENTION:I read an article in the May issue of (a

leading popular science magazine, namedeleted by the editor), which stated thata man by the name of Kane gave forty-two quarts of blood to save eighty-sixlives. The article stated that Kane's bloodwas of extraordinarily high quality. "Highin the 'Wasserman Test' by which physi-cians gauge the value of blood."

I was always under the impression thatthe Wasserman test is used for indicatingthe presence of syphilis. Please explain.

JOHN BERTHOLD,Philadelphia, Pa.

(The Wasserman test is a specific(opinions differ as to whether it is trulyspecific or quasi specific) for syphilis, andFrambesia commonly known as the yaws, acontagious disease of the skin, occurring inthe hot regions and generally marked byraspberry -like excrescences on the hands,face, feet, etc. It is caused by a micro-organism known as Treponema pertenue.

Positive reactions also occur in scarletfever, malaria, etc., but these reactions areatypical, and not to be confused with thetypical reaction of syphilis.

The important reaction in blood trans-fusion is to find whether or not thedonor's blood is compatible or incompati-ble with that of the recipient. Human be-ings can always be divided into any oneof four groups, depending upon the agglu-tinins present in the serum and the wayin which the cells agglutinate (clump to-gether). The article evidently had refer-ence to this agglutination test-Eurroa.)

Must Have College

A college education is certainly worthwhile, says this writer, who deplores

the fact that she didn't get one.

Editor, SCIENCE AND INVENTION :

Should the task be imposed upon yourchild to saw a huge limb off a tree wouldyou hand that child a saw with dulled andbroken teeth? Would you say-"If he hasperseverance he will get it off no matterwhat the handicap." Perhaps that is trueif he has the perseverance and the mettlein him he will. However, the task wouldbe enough with good tools, perhaps across cut saw and a fellow on the otherend of the saw to help.

A boy or girl now -a -days is like thechild with the old saw if he or she hasno college education. I know and I knowfrom experience. I am a High Schoolgraduate and had one year of college atIndiana University. That has counted butit is not enough.

Last year my husband, who is an Elec-trical Engineer, suddenly lost his positionas Superintendent of our Municipal Lightand Water plant. We have five children,we are paying on our home-it becamenecessary that I help to tide us over.

What could I do? I canvassed the situ-ation-I could not teach because I did nothave a college education. Although I havetaught everything from phonics up toLatin, French and Algebra for the pastsixteen years, that did not entitle me togo into a school room and thereby earneven a fair salary.

I turned toward Librarian work-thereagain I was faced with certain college re-quirements. It is true I have written afew articles and a bit of poetry for ourstate paper and they were printed, but Ilacked the technique they give you incollege and so that door reverberated as Iturned on to the next on my list.

In the Indianapolis Star there was anadvertisement-"Wanted-a graduate ofDomestic Science to take charge of andteach the making of tasty dishes."

You notice it said A GRADUATE. Ihave cooked for twenty years. I can doplain or fancy cooking and I can makerolls and breads and Lady BaltimoreCakes and French Dressings, etc.

I applied to a friend who manages aCountry Club for a job. You note I saida job, not a position. I told her-put meanywhere and everywhere. She has doneso because we were friends and I neededa lift. Had I had a college education Icould have given myself that lift.

Oh yes! I intend to succeed and evenam going to try for a Country Club to



Attractive DYNAMICSPEAKER Cabinet

By A. Brains

DETAILS OF SPECIAL B.B.L. DYNAMIC SPEAKER CABINET

18" -

--% BAKELITE

--I" CELOTEX

.---,..-___-_--

r.-4--- DETAIL OF CORNER

,I.BRASS-18"LONG.-4 SLOT FOR BAKELITE.

Ll-THREADED FOR

EX2xX SCREW.

HERE is a dynamic speaker cabinet which combinesthe features of attractiveness and compactness with-out sacrificing efficiency or quality. It can be made

up of many different materials and in different finishes.This is possible because the cabinet is lined with Motel-,which will prevent the vibrations that go through the wallsof the cabinet from reaching the back of the cone. Thecabinet shown is made of bakelite, but sheet metal, lightwood, celluloid or any other substance that is easily worked

Soldering Iron Controlfor Delicate Work

IT is not generally realized that an electric soldering iron,to he quick -heating, must operate too hot when in con-tinuous operation. Some means of control, therefore,

is desirable to prevent excessive heat and a marked shorten-ing of life. The simplest control is an adjustable resistancein series with the electric soldering iron. For this purpose,

the speed controlclarostat, capableof dissipating 80watts, yet provid-ing a resistancerange from 25 to500 ohms, is de-sirable. The short-circuiting pushbutton on the de-vice serves to in-crease the heatmomentarily, suchas for heating,while the resis-tance may be setfor the "idling"heat. In solderingvery fine wire,such as in loud-speaker repairsand audio trans-former secondaries,this heat controlwill be found in-valuable.The heat control mounted on the work

Showing the complete ornamental dynamicspeaker.

and gives an attractive appearance may be used.As the whole cabinet acts as a baffle -board, itis not necessary to make the front as large asusual, thus making for compactness and betterproportion.

The cabinet is constructed as shown in thediagram. The back is left open, or a back piecesimilar to the front may be made, being surethat there is an opening about equal in area tothe opening in the front. The speaker chassis

is mounted inside, the mounting depending on the make ofchassis used. Care should be taken to fasten togethersecurely the parts of the cabinet so that there is no vibrationbetween them. If ornaments, like those in the picture, areused, they should not be of the type that will vibrate andcause extraneous noises. The openings in the back andfront may be attractively covered with cloth or some formof grill work.

Better results may be had with a celotex lining on the topand bottom, but that is not essential.

Home -Made Stroboscope toStudy Moving ThingsHOW would you like to study different things in motion

as if they were standing still? That may be doneby means of the stroboscope --a device which causes

the periodic illumination or viewing of a subject, so thatit may be seen at the same point in its cycle of operations,cycle after cycle.

A B -eliminator feeds a neon lamp with a continuously vari-able resistance, the table type clarostat in series. In operation,the resistance is adjusted so as to obtain a periodic flickerfrom the neon lamp, and this flicker is used to illuminatethe object being studied.

Studying the whirling blades of an electric fan with thestroboscope.bench.

1


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DYNAMICSPEA.ER,

SET INPI,IT 4:0

FIELDS vSUPPLY

in. rris.1r4s. 4r. ie. isP 4111.41w dor 4IW 411

40 411111, 40. 41.1. 41110. .11.11, 4.0 4111.10 4.111, 41.10 r40. 40.

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PICK-UP 61-'7 c'

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R9 245RIO

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79 710 T

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New Nine -TubeA. C. Receiver

Gives Superior Tone Quality

ONE of the latest products of a well known phonographmanufacturer is a combination electric phonograph andradio receiver which is housed in a compact cabinet of

burl walnut veneer and bird's-eye maple. The electric phonographis as new as the receiver itselt and records are reproduced byutilizing part of the radio system.

The radio receiver employs nine tubes and is equipped withfive stages of radio frequency amplification. Two 245 -powertubes are used in push-pull in the last audio stage. A 227 is usedfor the detector and 226 tubes in the radio frequency and firstaudio stages. A full wave rectifier of the 280 type is used inthe power pack. A high degree of sensitivity is made possibleby the use of a mechanical system of micrometer adjustments onthe tuning condensers which permits automatic alignment of thetuned radio frequency stages throughout the entire broadcastspectrum. Each set of condensers is aligned at the factory andlocked into position. Anew method of stabili-zing the radio frequencycircuits permits a highdegree of selectivitywithout causing anydecrease in sensitivity.

Tuning is accom-plished by means of asingle lever controlwhich operates over afull vision illuminatedscale accurately cali-brated in kilocycles,with a space at the topfor marking the stationpositions. Accuratevernier adjustment can

At the right is a photo-graph of the front viewof the receiver and elec-tric phonograph showingthe new tuning control.

Circuits of new Victor 9 -tube a.c. receiver.

Above is a rear view of the combination showing thereceiver itself, power park, and dynamic speaker. Thecombination instrument is equipped with an induction disc

motor, 12 -inch turn -table and straight pi(k-up arm.

be obtained by turning the knob of the lever. Thereare three additional controls; namely, the volumecontrol, the radio record transfer switch and a smallsnap switch which controls the supply current.

Within the set is a harmonic modulator which en-ables one to regulate the emphasis on the base ac-cording to the listener's preference or to suit theacoustic properties of the room in which the receiveris used. This modulator is set at the factory for thebest reproduction over the entire musical scale. Theamplifier unit is placed below the set with the dy-namic speaker. Specially treated and metallizedcloth is used for the cone (Continued on page 562)


New Radio DevicesDe Fry com-binationradio-phono-grap and.talking moviecabinet,showing themovie equip-ment. Thesmall door atthe front ofthis compart-ment opensto permit therays of lightfrom theprojector toreach the

screen.

Combination Radio -Phono-graph and Talking Movie

NOW, in one cabinet, the American home may installthe four entertainment inventions of the age-radio,phonograph, movie and talkie. The QRS-De Vry

Corporation has recently put on the market such a combina-tion. The combination includes the latest model De Vry16 mm. motion -picture projector, which is connected to theadjoining phonograph turn -table mechanism by a synchroniz-ing shaft. The radio is an 8-9 tube a.c. set, using screen-grid tubes.

Well -Designed.Audio

AmplifierANEW audio

ampli fier,called the PAM,recently put onthe market, willsupply powerenough to filllarge halls andauditoriums withsound waves. "tcThis amplifiermay be used to -amplify radio signals after they are received for reproduc-tion of phonograph records and for public address systems.The unit is completely self-contained. It plugs into the110 -volt a.c. lighting circuit. Four tubes are used and theyare one 227, one 281 and two 245's. It operates directly intoa loud speaker; it is built by Samson Electric Co., Canton,Mass.

Short -WaveConverter

OF interest to theshort-wave en-

thusiast is the newshort-wave convertermanufactured by theWestside Radio &Elec. Co., of Miami,Fla. The converteris designed to workwith any receiver.

-4*

"Straight -Line" Tuning Dial

THE Master Engineering Company, Chicago, Ill.,nounces the Master Tuning Selector, which is intended

to replace the regular tuning knob on the set. The indicatortravels in a straight line instead of a circle.

an -

Device to RegulateVoltage

THE new Amperite self-adjusting line control regu-

lator is a recently perfected de-vice constructed in a glass -bulbform which is remarkable forits regulating efficiency. It isuseful for a.c. receivers andacts as an insurance againstburning out expensive tubes.

Super Volume ControlPr HE new volume control,.I. called Super TONATROL,

manufactured by Electrad, Inc.,New York City, is a long -lifecontrol especially designed forhigh voltages. It easily dissi-pates 5 watts without breakingdown or varying in value. Theresistance element is fused to anenameled metal base. A pure sil-ver floating contact is used. Themetal cover aids rapid heat dissi-pation. It has many applica-tions.

A New Push -Pull Power AmplifierTHE latest device of the Radio Receptor Company, New

York City, is this push-pull power amplifier, using thenew 245 tuber. Push-pull amplification has many friends.


A Monthly Question and Answer Department Conducted with aView Toward Helping Radio Constructors and Experimenters

Making the A -EliminatorWork

(728) Mr. Henry Doyle, Gal-veston, Texas :

Q. 1. Recently I constructed, anA -battery -eliminator, utilizing myold two -ampere charger as a sourceof power and rectifier. The filterconsists of a special condenser of2,000 mfds. manufactured for thatpurpose, and a large A -choke. Thefilter did not work satisfactorily and Ihad to connect up the old battery to theset again. There was a bad hum and therheostats on the set would not cut thecurrent down enough. What can I do toeliminate the hum and cut down the cur-rent?

A. 1. Eliminators of this type are notalways satisfactory, because the source ofsupply and rectifier are not designed forthe filter. In such a case it is usual toemploy a so-called brute force filter wherethe chokes and condensers are so largethat the hum is choked out. This is thetype filter you are using. The only waythat you will get satisfactory results is byincreasing the size of the filter.

You may use your old battery as anextra large condenser to increase the size

RADIOORACLE

Devoted Only to Queries ofGeneral Interest

2 -AMP

CHARGER

FILTER.r -24-1

LOLD STORAGE

BATTERY USED A5 ACONDENSER

TO FILAMENTS.

Connection of old storage battery as ahigh -capacity condenser.

of your filter. Give the battery a goodcharge, fill it up with distilled water, andconnect it as shown in the diagram. Asyou are only using the battery as a con-denser, and not as a source of current, itwill not be necessary to charge the bat-tery again. The internal resistance of thebattery will also keep the supply voltagedown to six volts so that you will haveno trouble with the filaments overheating.

Although you have not eliminated thebattery, you have done away with thebother of looking after the battery, forit will not be necessary to subject it toperiodic chargings. It will only be neces-sary to add water to the electrolyte abouttwice a year, for practically none of thewater will be lost through electrolysis.

What Farads and Henrys Are(729) Mr. F. C. Bosset, Houston, Texas,

asks:Q. 1. Among the various and numer-

ous technical terms used in radio are theexpressions - micro -farad and micro -henry. I have referred to numerous bookson these two terms and cannot seem toget a clear definition or conception ofthese two terms. I would be very grate-

ful if you could explain them. Possiblyyou can illustrate in some way, so thatthese two terms may become clear to me.

A. 1. Just as the gallon, pint or gill isa unit of measurement to compare ormeasure liquid, and the inch, foot or yarda standard to compare or measure size orlength, so the henry and farad are unitsof measurements to compare various sizesof coils and condensers, respectively.

The unit of capacity is the farad. Howlarge this unit is may be somewhat vaguelysuggested to our imagination by the factthat if everybody in the United States had18 each of the so-called .0005 micro -faradcondensers (usually equal to 18 plates),the total capacity of the whole lot con-nected in parallel would be one farad.The question naturally arises in every-body's mind why such a huge unit waschosen to begin with. A volt, the unit ofpotential, is a convenient size. An am-pere, the unit of current, is also con-venient. An ohm is an easily obtainedquantity of resistance. These three arethe basic units. Starting with these three,such a unit as a farad is a derived unit.That is, it follows as a matter of defini-tion.

A condenser is fundamentally a dielec-tric with a conductive plate on each sideof it. Connected to an electric source, thecondenser is charged. The larger thecharge, the greater the difference of poten-tials between the two conductive plates, andthe equation is Q = E times C. WhenQ is the charge, E is the potential, and Cis a constant for any particular dielectricand arrangement of parts. C is a ratio ofQ to E, and we call it the capacity.

The unit of capacity is the capacity ofa condenser charged to a potential of1 volt by a unit quantity of electricity.The name of a unit quantity of electricityis a coulomb, which is the charge trans-mitted in one second by a current of oneampere. Really, therefore, the farad isthe ratio of the unit of charge to the unitof potential.

Like the unit of capacity, the unit ofinductance is a tremendous unit. It is thehenry. While in capacity we usually dealwith the millionth part of a farad, ininductance we usually deal with thethousandth part of a henry, the millihenry.

The henry is also a derived unit and itssize is due not to design but to force ofcircumstances. It is the inductance in acircuit when the electromotive force in-duced in a circuit is one volt and theinducing current varies at the rate of oneampere per second. It, therefore, is de-rived from the unit of voltage and a unitof current.

Operating Radio ControlApparatus

(730) Mr. D. Brown, Washing-ton, D. C., asks :

Q. 1. In making radio controlapparatus, is it necessary to use acoherer and decoherer arrangementto operate the relay? I have seenseveral descriptions of radio con-trol apparatus and all of them usedsuch an arrangement. I should think

you could use a modern vacuum tube re-ceiver, rather than the old-fashionedcoherer and decoherer.

A. 1. Modern receivers with poweramplifiers may be used to operate relaysfor controlling objects by radio. Anytype of receiver that will produce an im-pulse clear enough to operate the relaymay be used.

The reason you have always seen thisapparatus connected to a coherer and de-coherer receiver is that such an arrange-ment permits the use of an ordinary lowohmage relay. It is possible to balancethis with the coherer and decoherer ar-rangement, which is itself of low re-sistance.

Vacuum tubes have a high resistance

TO B- 10,000-100,000 OHMS

GROUND J7OR

.5 MFD.atO

I-

O

IC -BAT.

OUTPUT.0

B+A volume control for AC tubes which does

mot cause distortion.

output and it is necessary to have a highresistance relay to function properly withthem. This makes the arrangement verymuch more expensive and complicated, forhigh resistance relays of this type are verydelicate and costly instruments and it isnecessary to arrange complicated protec-tion apparatus for them.

A simple type coherer receiver is un-reliable, except over a distance of a fewfeet. But it enables the experimenter tobuild apparatus by which he can studyradio control at a price within his reach.

Volume Control for AC Tubes(731) Mr. William Acker, Canton, Ohio:Q. 1. How can I make a simple vol-

ume control for a set using AC tubes?A. 1. You can make a simple volume

control for your set by using a variableresistance and condenser as shown. Anycondenser of half a microfarad or moremay be used, and the resistance shouldbe of the continuously variable type, andshould have a resistance of from 10,000 to100,000 ohms. Such a volume control willnot affect the quality of the receivedsignals.

538 Science and Invention ' October, 1929

Scientific HumorA Monthly Fun Page for Those

VICE VERSAA man saw an advertisement of a safety

razor with an automatic attachment for re -sharpening blades. He wrote to the com-pany-Gentlemen :

Enclosed find check for which please sendme one of your new scientific safety razors.

Very respectfully yours,Mr.

P. S. I forgot to enclose the check, butI presume that it will make no differenceto a company of your standing.

The company replied:Mr.Dear Sir :

Enclosed find your safety razor. We hopeit will give you good service.

The Co.P. S. We forgot to enclose the razor, but

we presume that a man with your cheekwon't need one.

-Sidney Gnann.

A BALE FOREVERY AVI-

ATORAL-Well, at

last a real usefor all our oldstraw -piles h a sbeen discov-ered.

TIM - Whatis it ?

AL-They spread them along underthe airplane routes to improve the land.

-L. S. Allen.

BUT MAN MANAGES HERSHE-"Woman is a great force in this

world. Even a big locomotive is referredto as 'she.'"

HE-"You are right-but it's because ofthe noise it makes."

-R. W. IV. Williamson.

HE'S A SAXPLAYER

PROF.-Howe,have you anyorganic trouble?

HOWE-No, Iam not the leastbit musical.-Miss M. M.

Roger.

Who

First Prize-$3.00NO MOONSHINE

Enjoy a Laugh

CORONER-Are you sure it wasmidnight when you heard the twoshots fired ?

WITNESS-Yes, I was in the gar-den and noticed the time by the sundial.

CORONER-And how could youdo that in the dark?

WITNESS-I had a flashlight.-Leslie F. Carpenter.

ALL jokes published here are paidfor at a rate of $1.00 each;

$3.00 is paid for the best joke sub-mitted each month.

Jokes must have a scientific strainand should be original.

Write each joke on a separate sheetof paper and add your name and ad-dress to each.

Unavailable material cannot bereturned.

THE CATSI had a cat. A tortoise shell.She died-and really dyed quite well.She made a muff that looks like mink ;And it is curious, I think,That though she no more care demands,That cat is still upon my hands.

-Grace E. Holman.

SCIENTY SIMON SCIENTIST

HAS HOLE ON OTHER SIDE"Look, you have your socks on wrong

side out.""Yes, I know. My feet were hot, so I

turned the hose on them."-Orville Vanderlip.

ALSO EATING HIS HAND"Is Bill a good chemistry student ?""Good, I should say he is. He's got the

acids eating right out of his hand!"-Margaret Clopp.

BUT IT DESTROYS THE CLOTHDid you know that: Limberger cheese

will remove the odor of onions. So willsulphuric acid remove ink stains from gar-ments.-Mason.

TRY PRUSSIC ACID"Have you some of that gasoline that

stops knocking ?""Yes."

"Then give my wife a glass."-Elisabeth Buerman.

SAND, OFCOURSE

SEA CAPTAIN-Over there isan ocean liner.

OLD LADY-My gracious,and pray tell mewhat they linethe ocean with?-Leslie F. Car-

penter.

ococeAni

1,,sNrs.J,,PoNst F

LINING/

WAS SHE BLINDFOLDED?DOCTOR-What did that flapper do

when you put the thermometer in hermouth ?

NURSE-She asked me if I had amatch. -Leslie F. Carpenter.

WITHER ORNOT

flowers are usu-ally pretty wellwithered.

T o m-Y e s ,

but they arenever pressed.-S. TV ill lams.

5A-4 JOE -- 11301-K.:HTTHIS OLD LIFT POMP DIRTcl-keAP YESTERDAY - - IT'SOUST THE THING. WE NEEDTo THG, UP A 'WATER SUPPLY34STENN FOR OUR LABUP in.1 THE

ATTIC !

O. lc. eFt-(3i;:)! - 140,4/r,5 .11 -UP THERE ).--,--'

-7 I'''ic." 7JSs- wictcs !eLN or Ev Ent Ai

°Don !

SC (ENCe LESSON4-40. 55

ToE OPERATION OF THELIFT POMP. A stAcUpt-I IS PRO-

DUCED IN THE PUMP BARRELB1 REPEATED UP -STROKESOF THE "PISTON, ANC/ THEOUTSIDE AIR PRESSUREFORCES WATER UP TO FILLTHIS EVACUATED PLACE THE PRESSURE OF THEAMOLWTINC, TO 14.7 1.15S- PERSQ. INCH IS 51-WriciEkT TOBALANCE THE WEIGHT OF AWATER COLUMN 37. FT. INHEIGHT... HENCE AN ORDINPP

LIFT 'POMP WILL NOT beAELE To ReAse WATER 1.-AW-1 HIGHER LEVEL.

October, 1929

Hosiery Mending Threads

.....

Science and Invention

Latest Patents

No. 1,716,007, issued to Frank Rosenthal.It is a well-known fact that stockings aresubject to runs. Ladies' stockings in generalare manufactured in such a wide varietyof colors that it is quite impossible to getthe shades of thread to correspond exactlywith the color of the material of which thestocking is made, and still more difficult tosecure this before the run gets beyond re-pair. For this reason the inventor hasprovided a stocking with thread which can

be instantly used.

Automobile Pontoon

No. 1,715,905, issued to Alexander L. Dmi-trieff. This is a pontoon of large enoughsize to accommodate an automobile. It isprovided with a series of rollers on whichthe rear wheels of the auto rest andwhich transmits the motion of these rearwheels to the propeller. The front wheelsare locked in place and the boat is steeredby an auxiliary wheel coming up along-

side of the usual driver's position.

Foam Bathing Apparatus

No. 1,716,109, issued to Gustav AdolfBruggmann. This device is intended to beattached directly to a vacuum cleaner sothat everyone can get a bubble bath at aminimum of expense. The tube is per-forated with holes and is connected to thevacuum cleaner at the point usually occu-pied by the bag. The air is thus forcedinto the bath and it produces a froth with

the soapy water.

Notice to Readers:These illustrated and described devices

have recently been issued patent protectionbut arc not as yet, to our knowledge, avail-able on the market. We regret to advisethat it is impossible to supply the correctaddresses of inventors of the devices toany of our readers. The only recordsavailable, and they are at the Patent Officeat Washington, D. C., give only the ad-dresses of the inventors at the time ofapplication for a patent. Many monthshave elapsed since that time, and thoserecords are necessarily inaccurate. There-fore, kindly do not request such informa-tion, as it is practically impossible to ob-tain up-to-date addresses.

Use for Old Cones

No. 1,716,215, issued to Charles K. Dunlap.In the textile industry fibre cones are manu-factured in great numbers and are used inconnection with knitting machines, thethreads being wound on these cones. Afteruse these cones are generally thrown away.They are sometimes sold to paper mills forreduction into pulp. The inventor hasmade use of these cones and he cementsthem together, producing a rod or a polefound particularly suitable for use as acarpet pole. The outer surface can alsobe ground and polished smooth and can beimpregnated to make it even more durable.

New Loud SpeakerNo. 1,715,886, issued to Frank M. Ashley.Here is a horn made of molded or plasticmaterial and provided on the front with asuitable design, extending above the topas a sound reflector; this is hinged to thebody of the horn and the angle can be ad-justed, so that the sound will be reflectedin any direction. It is claimed that thetones in such a horn are transmitted <with-

out material change in quality.

539

Golf Club Speed Indicator

No. 1,712,537, issued to Walter P. White.here is a device attachable directly to thegolf club which is intended to help the stu-dent to improve the effectiveness of hisstroke. As will be seen there is a vanemounted on the top of a golf club. Thisvane presents an angle with the air, exceptas the stroke nears its completion. At thispoint the vane is disposed directly acrossthe path of the air in the room, with theresult that it moves and causes a needle toregister the force of that stroke. Suitableprovision has been made for obtaining thegreatest amount of accuracy by adjust-ments which can quickly and easily be

taken care of.

Combination Sleigh and Boat

No. 1,716,230, issued to Clifton M. Ingram.This invention relates to a combined sleighand boat. The device is driven by airscrews and can be steered easily on eitherland or water. The portholes on the sidesare water -tight as is the door. The bodyis of laminated steel construction and con-sequently the device lends itself admirablyfor both winter sport and use. A periscopeis provided and the brake is intended for

use on the ice only.

A Toy Airplane

No. 1,710,219, issued to Ernst Paul Leh-mann. This is a gyrostatic toy, that is onein which the movement of the toy is pro-duced by spinning a fly -wheel by hand orin any other way desired. As will be ob-served in the diagram, the fly -wheel coupleswith the wheels of the toy through theagency of .gears. This causes the toy tomove forward, until the force originallyimparted to the fly -wheel has been ex-

pended.


A Monthly Scientific Question and Answer PageIs Gila Monster Poisonous

(2326) Mr. Charles D. Trone, Tampa,Fla., asks:

Q. 1. Is the lizard known as the Gilamonster found in the desert regions inArizona and New Mexico really poison-ous?

A. 1. There has been some question asto whether the Gila monster is actuallypoisonous or not. Nevertheless, manydeaths have been known to have beencaused directly by this lizard. It istherefore generally conceded as beingpoisonous.

, '7416c-7. 1.114401

Here is an illustration of the Gila Mon-ster, the bite from which often proves

fatal.

Lt. Comm. C. M. Cree, R.N., retired, in"Discovery" writes an interesting synopsisof the poison apparatus of this lizard inthe following way: "The poison apparatusof the Helodermis is quite unique anddiffers entirely from that of any of thethree main types of poisonous snakes. Inthe Gila monsters the poison glands, whichare two in number, are each formed offour lobes. These glands are situatedone on each side of the base of the lowerjaw instead of being either at the rearof the upper jaw or contained within thebody as in the case with the venomoussnakes. The means of utilizing the poisonis quite different. No fangs or groovedteeth, such as are found in snakes, arepresent in the upper jaw of the Gilamonster. Instead the poison of the animalis conducted from the glands through fourducts on each side of the lower jaw tothe bases of the eight grooved teeth whichare loose set in a somewhat forward posi-tion in that jaw. These teeth are groovedwith canals or channels on the insidethrough which the venom is fed. Whenthe reptile grips its prey it makes a grind-ing movement with its jaws which con-tracts the glands, thus forcing the poisonup through the groove in its teeth andinto the wound caused by the bite."

There are many cases on record wherepersons were bitten by the Gila monsterand suffered little ill -effect. These resultsin all probability were due to the factthat the lizard was only able to succeed inbiting with the front teeth, and was notable to enter the grooved teeth in thewound and inject the venom. The writerconcludes that quite different stories wouldhave been told had the Gila monstersmanaged to utilize even a small quantityof the venom.

Running from a Tornado!(2327) Mr. Thomas J. Alden, New Lon-

don, Conn., asks:Q. I. Is it not possible for a person to

get out of the path of a tornado when heor she sees the tornado approaching?

A. 1. Much depends on the tornado.

TheOracle

Not only is the size important but thespeed at which the tornado travels andwhere the person will be at approxi-mately the time the tornado reaches him.

According to the Monthly Weather Re-view, eight tornados were reported in thenortheastern portion of Arkansas dur-mg the afternoon and the early portion of

The "Oracle" is for the sole benefit ofall scientific students. Questions will beanswered here for the benefit of all, butonly matter of sufficient interest will be pub-lished. RuleS under which questions willbe answered:.1. Only three questions can be submitted

to be answered.2. Only one side of sheet to be written

on; matter must be typewritten or elsewritten in ink; no penciled matter con-sidered.

3. Sketches, diagrams, etc., must be onseparate sheets. Questions addressed to thisdepartment cannot be answered by mail freeof charge.

4. If a quick answer is desired by mail, anominal charge of 50 cents is made for eachquestion. If the questions entail consider-able research work or intricate calculations,

be charged. Corre-spondents will be informed as to the feebefore such questions are answered.

the night of April 10th. One of thesetornados covered a path 1,000 feet wideand 18 miles long. It moved at suchrapidity that it was reported at threetowns along the line of its travel at thesame time. It was only four minutesfrom the time it was first seen until itwas entirely gone. Thus, the 18 mileswere covered in the time of four minutes.

One can run away from a tornado, ifone runs in the right direction and thepath of the storm is not too wide or

rapid.

If the individual in the path of the stormran along the lines of the storm and inthe general direction in which it wastraveling, the individual would then haveto run at a speed of 4'A miles a minute.Of the twenty-three tornados in Arkansas

during the month of April 1929, one hada path of 3,500 feet wide and 65 mileslong. A much milder storm had a shortpath not over a mile in length and only225 feet wide. One could probably getaway from this, but then such small onesrarely do much damage.

The Moon Rocket(2328) Mr. J. A. Sturgeon, Los

Angeles, Calif., asks:Q. 1. How is it possible for the God-

dard rocket to reach the moon when thereis no air against which the explodinggases of this rocket can react?

A. 1. There seems to be a general mis-taken impression that the gases exudingfrom the rocket must react againstsomething in order to drive the rocketforward. This is not the case at all.The gases as they explode, pass outthrough the funnel of the rocket, or the

POWDERASE5 EXPANDING HERE

DRIVE ROCKET FORWARD

This explains the action of a rocketand shows why the rocket will traveleven in interstellar space. Gases do

not need to react on any air.

nozzle as it is technically called. In ex-panding, these gases react against thesides of the nozzle, causing the rocket tobe driven forward. Professor Goddardhas carried on extensive experiments atClarke University in Worcester, Mass.,wherein he has proven that the rocketgives even better results in a vacuum thanit does in an air -filled chamber. A com-plete article on this subject appeared inthe February, 1920, issue of SCIENCEAND INVENTION Magazine. Youwill find there a complete explanation ofhow the rocket works.

Colored Gasoline(2329) Mr. Homer Adams, Wain-

wright, Okla., asks:Q. 1. What is ethyl gasoline and why

the color found in some gasolines, suchas red or green?

A. Ethyl gasoline is an anti -knock com-pound made from the raw materials, ethylalcohol and lead. These two substancesare treated with other compounds, whichare not disclosed at the present time,and then reacted together and washed insulphuric acid after which the halogenbearing compounds are added.

The ethyl fluid is tetra -ethyl -leadtreated with halogen bearing compounds.The latter has been added to neutralizethe effects of the lead oxides which havea tendency to attack the spark plug ter-minals. Since the addition of the halo-gen bearing compounds in the form ofethyline bromide and trichlor-ethyline. thespark plug difficulty has been eliminated.The knocks due to carbon and pre-ignition are eliminated by using an anti-knock motor fuel such as this ethyl gaso-line. Gasoline is colored by special dyesusually red or green which in no wayaffect the efficacy of the product.


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542 Science and. Invention October, 1929

"The Boss WasStumped"

"Hs was trying to figure out a way to speed up themachines. I could see he was stumped and 1 askedhim if he would let me try my hand at it.

" 'Go ahead,' he said, but I don't believe you canhelp much. Looks like an outside job to me.'

"So I started right in and pretty soon I had thewhole thing worked out. The boss was watching meand I could see be was surprised.

"'How did you learn all that?' he asked in thatquiet way of 'his. And then I told him I'd beenstudying at home nights through the InternationalCorrespondence Schools.

"He didn't say anything more and I thought hehad forgotten all about it until he called- me in hisoffice a few weeks later and said he was going to makeme foreman and increase my salary $75 a month."

That's a true s'..,ry of what spare -time study has done forlust one man. There are thousands of others. Why don't youtake up a home -study course with the International Corre-spondence Schools and prepare yourself to earn more money f

INTERNATIONAL CORRESPONDENCE SCHOOLS"The Universal University"

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New Hudson River Bridgeto Carry Vehicles and,Trains'

(Continued front page 492)

and also extreme grades on the New YorkSide. This huge bridge design intendedto cross the North River and relieve agreat amount of traffic from New York toNew jersey, has been under considerationfor more than forty years,' and among itsoriginal charterers was Gustave Linden-.,thal,.

the',eminent bridge engitieer,i who is'president of the North River' Bridge Com-pany, the present proposers -in cinjunctionwith the .Baltimore and Ohio Railroad.

The bridge plans also provide that therailroad tracks after they leaire the bridgeon the -New York side, would pass downinto, a subway and remain' undergroundthroughout theloop, 'ver which 'the trainscould return after passing from the sta-tion. Only the station building would belocated above the ground. On the NewJersey side the through tracks would bediverted to .. a belt line, 'Ohnecting thevarious prominent railroads4rminating onthe river front.

New York City, a maze of tunnels andbridges! The site of the ttoposed newbridge, across the Hudson River at 57thStreet, is to be noted at the left center of

the mat.

Dust !(Continued from page 510)

Many volcanic eruptions send immensevolumes of dust into the atmosphere.

In 1883, when Krakatoa erupted 4 cubicmiles of solid rock were sent up into theair, the finest particles floated about forseveral years. The fact that meteors whenthey enter the earth's atmosphere areburned up and disappear leads to the con-clusion that the resulting dust or remainsmust stay.in the atmosphere in the shapeof very fine dust or larger particles whichgradually descend to the earth's surface.

CompleteShort -Wave

ManualUp -to -the -Minute Data-All

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Who Will Build theFastest Ship?

By James C. Young(Continued front page 495)

Mechanically and structurally theBremen marks an epoch-nothing less.Below the water line she departs a longway from accepted standards. Herbulbous nose extends outward twenty feetand backward fifty feet. bending down-ward, in the way of a heavy fin. And inthis fin is the secret of the Bremen'ssteady structure and swift pace, to nosmall degree. It was developed in partas a result of submarine experience. Atthe extreme bottom the hull practicallyequals in width the extreme width of themain deck. Thus, the Bremen's greatestdepth and weight being in the water,she might be called a submerged object,of which only the top skims the water.In effect, then, she is both airplane andU-boat.

Inside the big craft her mechanical ar-rangements command the first attention.She has two complete engine rooms thatmay be operated singly or in unison.Should accident affect the machinery inone, theother remains entire. Each has threeturbines-high, intermediate and low pres-sure-attached to four shafts-twelve tur-bines in all. They operate the propellershafts by single reduction gears.

The "Bremen's" electric fountain, withever-changing colors.

THERE is nothing especially new aboutthe Bremen's mechanical basis, but in

application a great deal has been accom-plished. Needless to say, the change fromcoal to oil reduces her weight of fuel andstorage space. And she has only twenty-one boilers, compared to the forty -odd ina ship such as our Leviathan, once aGerman craft. The Bremen's horsepower-120,000-is about twice that of the Levia-than, or twice as much power with half thenumber of boilers.

In a kind of well between stacks, standsthe catapult. It is eighty-eight feetlong, and operates as a device to shoot aplane off and upward. One and a halfseconds to start ! On the Bremen's firsttrip catapult and plane performed per-fectly. Both will be used in the regularmail service from ship to shore, and alsofor passengers who may desire to gocatapulting.

Toward the stern and bow, on everydeck, stands an instrutnent more humanthan an adding machine. Ask the machinewhere you want to go, and read your an-swer in its electric signal. Merely push abutton and the answering flash upon theglass diagram shows the way.

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10,000 Buttons Command Service

SPEAKINGof buttons-there are ten

thousand of them, to turn on lights,summon stewards, and what not. Aworld of buttons, as it were. The Bremendesigners installed an electric bulb inevery possible spot where a human wantcould need one. The ship is exceptionalin its lighting arrangements, easily thebest seen in the port of New York. Bring-ing, as well, some new conceptions toAmerican eyes, without being futuristic,the Bremen is modernistic. Its salonchandeliers take the form of clouded glasscut into long strips, medallions and designsunfamiliar to American eyes.

American Expert DiscussesBulbous Nose

MR. FERRIS. the American designer.discussed with the writer some of

the developments in steamship construc-tion.

"The bulbous nose was discoveredfifteen years ago by our Navy Depart-ment," he said. "It operates in the waythat a fish swims. Most members of thefinny tribe are flat or round, generally ablunt body. If they had to swim half sub-merged and half on the surface theywould make slow progress. But a fishswims submerged and the shape of thebody is exactly suited to that kind ofprogress. This principle is exemplifiedin the snub-nosed ship.

"After the Navy Department's discoverythe principle was applied to one merchantship, considerably improving her speedover ships of similar power. Then camethe war and an inclination to follow theknown paths. Ship owners were not in ahumor for experiments. Since the warwe have gradually reached the point wheremarine development may be expected to goswiftly forward. Four years ago I usedthe snub-nosed principle in building theIroquois and Shawnee for the Clyde Line.both of them faster ships than they wouldbe with the usual keels.

"The Saratoga and Lexington of ourNavy have bulbous bows, and both areturbo -electric drive ships. Undoubtedlythis principle will increase the speed offuture steamships. How fast can theygo? Well, it is not only a question ofphysical possibilities, but of profitableoperation. With our knowledge of struc-tures and power we can build ships to dothirty knots or better. That brings uswithin the possibility of four days toEurope. Whether it will prove a matterof practical operation remains to beshown.

Shall We Build Larger Ships?"TT is unlikely that ships will grow-I- larger. The Leviathan is just under

60,000 gross tons, and I doubt if we shallbuild a vessel much larger. The problemis compression of weight and power toraise speed. No doubt we shall havethousand -foot ships. They can be builtlonger and larger. What purpose wouldthey serve? A thousand -foot ship is along structure. Think of that-a thou-sand feet of solid structure drivingthrough the water at high speed.

"Marine construction is on the point ofvast development. Although the oceanrace halted on the coming of the war, andhas been delayed until now, we havelearned a great deal about ships in thattime. The science has not lagged. Why,it is no longer ago than 1910 that I builtcargo boats with sails as well as engines.The new ships of the United States lineswill excel any ever built. How could wedo less? The Germans have been daringin their departures on the Bremen, goingfarther in many particulars than any ofus have gone before." Their new ships

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are an evolution of several sciences, anatural product. Ours will go a step be-yond. In this country we have the ac-cumulated knowledge of the world's great-est power experts. What will prevent usfrom building faster ships than anybodyever built before?"

The United States liners will cost about$25,000,000 each and should be ready intwo years. Report places them at 55,000gross tons, and a thousand feet long. Ex-periments are under way in the modelbasin at Washington to determine mattersof construction. That they will be bigcraft-even the very biggest-is indicatedby the plans for a passenger carryingcapacity of 3,000 persons.

Other Nations in the RaceM EANWHILE the other maritime

powers are making ready to enterthe race, in which the Germans have ob-tained a signal start. Their two ships-the Europa and Bremen-and the FrenchLine's Ile de France are the only vesselsof the stellar class built since the war.Anything above 40,000 tons may be con-sidered of the first grade in ocean mam-moths. The Ile de France, though not sofast as the Germans, is a model of ele-gance. She is to be followed by a newqueen of her fleet, which French Lineofficials also have said will be "the biggestand fastest afloat."

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The British fleet, big and numerous infast ships, antedates the war in all par-ticulars and is German in no small partof its origin. The Bremen has scrappedthe speedsters of the British lines. Noneof them can get much nearer than a dayto the Bremen, excepting the Mauretania.And it may be affirmed that the Britishwill not stand idly by, for "Britannia rulesthe waves." Or she used to rule themwith her fast ships in the Atlantic trade.

The 'White Star Line has laid the keelof one super -ship and projected another,but the first was stopped when hardlybegun, and nothing definite has come ofthe second plan. Undoubtedly theBremen's performance was awaited be-fore pursuing construction. The Cunard,too, has discussed new ships, without ac-tion. Again the Bremen was the object ofattention.

Now come the two Italian lines of themajor class-the Lloyd Sahaudo and theNavigazione Generale Italiana - withplans for two monster ships. They ex-pect to cut the nine days, New York toNaples, by almost a third, six and a halfdays. Much lies behind this, Italian pride,for one thing, and a new bid to inducetourist travel, for another. The Italianships have done well in the last year ortwo and no one may doubt that they willbe behind in the ocean race. Among theirproposed innovations is refrigerated air tocool one in Mediterranean sunshine.

1

October, 1929 Science and Invention 54)

Financial InformationBy Alfred Caddell, Financial Editor

Question : What do you think of Elec-tric Investors as an investment? A. H. R.,Camden, N. J.

Answer: The common stock of thiscompany has a record of earnings thatentitles it to be classed as an invest-ment. For the twelve months endingJune 30, 1929, after taxes and interest werededucted, a net income of $12,272,028 wasreported, equivalent after dividends on the$6 no-par preferred stock, to $11.75 a shareearned on 948,364 shares of no-par com-mon. A split-up of the common, withvaluable rights, is predicted. The growthof this utility has been consistent and isindicative of the tremendous expansion inthe electric utility field which has been andis still progressing.

Question : I have noted the tremendousincrease in popularity in the outboardmotor field. What is your opinion ofJohnson Motors? C. A. M., Port Jef-ferson, L. I.

Answer: The Johnson Motor Com-pany, is one of the outstanding outboardmotor manufacturers. At the close of itsfiscal year which will end September 30th,it is expected that the company will shownet profit in excess of $500,000, which isequivalent to more than $5 a share on the95,000 shares of common outstanding.This would compare with $257,069 earnedin the fiscal year 1928, or $2.70 a share. Itis reported that sales are running nearly50 per cent in excess of last year..

Question : How does Bendix Aviationstand in your opinion? P. T., Wichita,Kan.

Answer: Bendix Aviation must ofnecessity be regarded as a speculation, be-cause it has yet to show earning power,having only recently been organized.However, this company is one of the mostattractive in the aviation field. Sponsoredby General Motors, it has absorbed someof the leading accessory companies in thecarburetor, magneto, wheel, instrument andallied aviation accessory fields. Inasmuchas all aircraft must embody this company'sor a similar company's products, Bendixmay be regarded as one of the fundamentalcompanies engaged in the aircraft fieldand its earnings should consequently growwith the growth of aviation.

Question : I own 100 shares of GilletteSafety Razor. I notice that there has beenconsiderable market activity in this stockbut not much of an advance. What do youknow about it? J. H. G., Springfield, Ill.

Answer: Gillette has undergone per-sistent liquidation on account of settlementof an estate involving large holdings. Butit is now believed that most of this sellingis out of the way, which places the coin -!Fly in a position to respond to the con-tinuous increase in its earnings. In thisconnection, it must be recalled that withone exception Gillette's profits have madegains yearly during the past 23 years.Gillette has met great success in recentyears in developing its foreign business,and is 7107C' developing new lines apartfrom razors and blades, such as officegoods, surgical instruments and other spe-cial devices.

Information on securities will be furnishedreaders of Science and Invention free ofcharge by mail and through these columns.A 2 -cent stamped, self-addressed envelopeshould be included in your letter. Addressyour inquiries toThe Financial Editor, Science and Invention, 381

Fourth Avenue, New York City.CORRECTION: Due to an oversight, copy-

right credit to New York Stock Exchange forphotos used on page 446 of the Septemberissue was inadvertently omitted.

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Ma IM ONO =I

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In this Department we publish such matter asis of interest to inventors and particularly to thosewho are in doubt as to certain patent phases.Regular inquiries addressed to "Patent Advice"cannot be answered by mail free of charge. Suchinquiries are published here for the benefit of allreaders. If the idea is thought to be of importance,we make it a rule not to divulge all details, inorder to protect the inventor as far as. it is possi-ble to do so.

OSEPH H. KRAUSShould advice be desired by mail, a nominal

charge of $1.00 is made for each question.Sketches and descriptions must be clear and ex-plicit. Only one side of sheet should be written on.

NOTE:-Before mailing your letter to this de-partment, see to it that your name and addressare upon the letter and envelope as well. Manyletters are returned to us because either the nameof the inquirer or his address is incorrectly given.

Power Wrench(1189) Leonard Gray, Livingston,

Calif., has designed a power driven speedwrench. He asks whether we advise himto apply for a patent.

A. 1. Power driven speed wrenches areemployed in practically every large factorywhere there is a use for such an apparatus.

While your speed wrench differs slightlyfrom other wrenches of a similar type, wedo not consider it to be an improvement.

We would not advise further action.

CLUTCH

eSOCKET

REVERSE GEAR

RELEASE TRIGGER.

FLEXIBLE SHAFT.

This is a suggestion for a power speedwrench to tighten and loosen nuts.

Film Box Fire Extinguisher(1190) D. H. Suitt, Palace Theatre,

Jacksonville, Texas, has designed a liquidfire extinguisher to put out fire in film -boxes. This consists of a fusible link con-nected with a tank of extinguisher fluid,the liquid in which tank is maintainedunder pressure.

A. 1. Why use a liquid fire extinguisherto put out the fire in film boxes when anordinary air -shut-off smothers the flameand is less likely to damage the film? Wecertainly fail to see any advantage in yourfire extinguisher principle.

Most projecting machines are so ar-ranged that they can take care of any

TANK HOLDINGEXTINGUISHER LIQUID.

PRESSURE GAUL

UT -OFF VALVE

MAGAZINEVALVE

THERMO HEAD

This dealce was suggested by a writeras a means for extinguishing fires in

motion -picture projectors.

film fire which may occur in either the topor bottom magazine. Furthermore, firesat these points very rarely occur. Theflame is generally started between theupper and the lower magazine and any shut-off which will prevent it from getting intothe magazines saves both rolls of films.

We see no advantage and would notsuggest further procedure.

Trouser -Pressing Device(1191) John Watt, Seattle, Washington,

has designed a system for the pressing oftrousers while the individual is wearingthem.

A. 1. Many attempts have been madeto develop mechanisms for creasing thetrousers while the person is wearing them.Up to the present time, no practical methodhas been devised.

We do not think that the system whichyou have suggested is any more service-able than those heretofore designed. Thereis, however, one way to determine this ;build a working model and give it athorough trial. Such a model will prob-ably not cost more than $25.00. Youshould have such a model in order tointerest the manufacturer. At the sametime, after building it, you might be con-vinced that patenting the system would

The rollers are to be heated and usedfor creasing trousers. Nothing is to be

done to the 'sides of the pants.

not be the best procedure until perfectedand you would consequently save manydollars.

You must further remember that manypeople like to have their trousers pressedin their entirety and are not satisfied withjust a sharp line down the front. If therest of the trouser leg is baggy it wouldlook foolish to have a straight front edge.One tailor some years ago devised a sys-tem for running a bead down the front ofthe trousers which was sewed permanentlyin place and which guaranteed a constantcrease at the front. We do not know whatbecame of this idea, but it is not verylikely that the method was successful.

October, 1929 Science and Invention . 549

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Einstein's TheoryBy Donald H. Menzel, Ph. D.

(Continued from page 517)an apple more than a pear, a doughnut, ora pumpkin pie.

If I had said, "Objects fall because oftheir heaviness, you would not think I hadexplained much. Yet, gravitation is derivedfrom a latin word that means just this.When you speak of the force of gravita-tion, you are speaking of the force ofheaviness. Thus analyzed, you see thatgravitation does not explain anything. Itmerely gives a name to the mystery.

P.-Aristotle's statement, "Anythingthat has weight is naturally endowed withthe power of moving toward the centerof the earth," then, is really not so far

ct\

Fig. 5a-Swing-ing the ballaround at theend of the scalein the fashionshown willcause the scale

to registerthe full ten

pounds.

removed from Newton's much more re-cent law of gravitation.

R.-That is true. Newton's real con-tribution was not so much the fact thathe supposed an attractive force existed (inwhich he evaded the issue) but that hegave mathematical form to his hypothesisand, notwithstanding the still mysteriouscharacter of gravitation, showed that hecould account for the motion of the celes-tial bodies by his law. But come! Let'sget on that merry-go-round, I ought tobe able to demonstrate Relativity there,pretty effectively. (Takes a billard ballfrom his pocket and lays it on the flatsurface of the suit -case he is carrying.)

R.-Note that while the merry-go-roundis standing still, this ball remains motion-less. Now watch.

(The merry-go-round starts.)L.-It is moving directly outward.

(Figure 2).P.-There is no secret about that. The

centrifugal force acts on the ball. Ofcourse it rolls away from the center. Themotion arises from the merry-go-round'srotation.

R.-You are, I fear, too prejudiced bythe fact that you see the trees of the parkapparently circling about you. If thoseouter regions were in total darkness, sothat you could not see the rotation, Idoubt if you would consider the problemso self-evident.

P.-Why not? Certainly I should stillfeel the effect of the centrifugal force!

R.-But it would not be so easy to de-termine that the force arises from truerotation. I venture to predict that youmight well consider that there is gravita-tional force, outside there, in the unknowndarkness, attracting you. The ball tendsto move outward. I am sure that it wouldbe quite possible to account for the motionof the ball by such a supposition.


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Making Sound BehaveBy John De Quincey

(Continued from page 513)

words : "Every partially or nearly whollyenclosed body of air assumes a rhythmicvibration which will resound either as atone or as a so-called reverberation when-ever that air -body is agitated; the largerthe volume of air the slower the rhythmof the tone or of the reverberation willbe." For example, an organ pipe emitsa certain note when a rhythmic vibrationis set up by the agitation of its air column.This principle was accepted so far asorgan pipes and the like were concerned.But Berliner declared that it applied be-yond these bounds, affirming that a hallis merely an enlarged organ pipe so faras this principle is concerned.

Accordingly, he reasoned, that the causeof the distressing reverberation of a hallis due to the agitating of its enclosed air -body by the speaker voice. In otherwords, that the reverberation in a hall isnothing less than the distinctive note of itsair column, which on account of its largedimensions has a vibration rate too low forthe human ear to distinguish as a dis-tinctive note, recognizing it only as avague booming sound.

His second proposition gets right to theheart of the problem : The harder or themore rigid the walls are which enclose anair -body the more intense will be its in-dividual tone or its reverberation."

He took a leaf from his experiencesin perfecting the gramophone, and pro-ceeded to illustrate the propositions justcited : "Many years ago when I began myinvestigations which led up to the Gramo-phone," he said, "I was bothered consider-ably by disturbing noises caused by thehorns which I used as sound collectors.Individual notes would be recorded andwould reproduce much louder than othernotes by the same singer or from thesame musical instrument. I soon dis-cavered that the disturbing sounds werealways in the same key and that theirnotes corresponded to the individual noteof the horn used for recording them.These horns were at that time usuallyseveral feet long and had flared openings,or so-called hells, from eight to twelveinches in diameter. Their individual notewas well within the register of the malevoice, so that hardly a song or a musicalcomposition could he recorded but thedisturbance took place. Soprano voiceswere not so much affected by it, but theinstruments used for accompanying thevoice were.

finally discovered that punching a cer-tain number of small holes into the sidesof the horns would destroy their indi-vidual resonance, thus removing the trou-ble. Such perforated, or as we used tocall them, 'ventilated,' horns faithfullytransmitted all sounds equally well to therecording diaphragm and permitted perfectrecording, and with all larger horns per-forations have been employed ever since.But when horns of this same large sizewere employed in reproducing machinesthe disturbance of individual resonancewas not noticed because the pressure ofthe sound vibrations came from thediaphragm outwards, and therefore thecause of the resonance, which is rhythmicelastic compression of enclosed air, didnot occur."

Remembering this experience he pro-ceeded to check on it with a lucid hit oflogic and a unique experiment. Take theviolin," he said, "it contains an enclosedbody of air. It ought therefore to havean individual tone, or note. But if that

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be true, then whenever the violinist struckthat particular note in his playing, itwould be greatly amplified by the sym-pathetic vibration. Now this is not thecase, for all notes from a violin are am-plified alike. The explanation must liein the nature of the walls that enclosethis body of air."

He therefore encased a violin in a half -inch coat of cement, thus making its wallsrigid. Presto, whenever a certain notewas played, the sound was greatly ampli-fied. While I was at his laboratory hehad a clarinet player seat himself in frontof this cement violin and play an ascend-ing scale. When the note was reachedwhich corresponded with the vibrationrate of the violin's body of air, it soundedforth with several times the volume ofthe other notes in the scale. No such re-sults occurred when a regular violin wasused.

From all his analysis and experimenta-tion Berliner finally reached the conclusionthat where the walls are able to vibratefreely they prevent the enclosed body ofair from developing A rhythm as a unit,thus eliminating reverberation and makingthe air -body neutral to all sounds. "Therewas nothing left then," explained Berliner,"but to invent some simple device thatwould cause the rigid brick or concretewalls of our modern halls to vibrate asfreely as the walls of a violin, or thesounding board of a piano." The "acousticcement cell," is the result.

The walls of his laboratory are brick.He struck a tuning fork and placed itagainst this wall. The sound could onlyfaintly be heard. He held firmly againstthe wall an acoustic cement cell, struckthe fork again, and then placed it on thisdevice. Clear and amplified, the note sangout over the large room. His investiga-tions led him to conclude that if evenone-fourth of the wall area is thus madevibratory with these "cells" a wholly satis-factory acoustic effect can be had.

The old school of acoustic specialists-and there are a number of eminent menwho have made this their life's study-looksomewhat askance at Berliner's analysisof the principles involved. They haveall built upon different premises-and havefailed to solve the age-old problem.

But Berliner chuckled a little and ob-served that real progress comes only whensomebody has originality enough to breakwith the orthodox ways of thinking. Hismind runs back some 53 years to the timewhen his application of the principle ofloose contact in the invention of the tele-phone transmitter violated a basic rulethat had rigidly governed electrical workup to that time. And why shouldn't he havesmiled? For though the skeptics may beable to argue plausibly against his logic,they are unable to refute the audibledemonstration of his theory, as illustratedby the New York Cotton Exchange, theDrexel Institute Auditorium of Phila-delphia, and other public halls.

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Noah's Ark Lives Againfor the MoviesBy Edwin Schallert


Lightning flashes and thunder rolls. Therain commences, first in a steady fall, andthen in cloudbursts and torrents. The seais churned into a frenzy by the wind.Great waves of water begin to dash overthe land. The skies and the ocean unitetheir force, building up a gargantuan tide,which sweeps the earth. During variousstages of the play, the toppling of thetemple pillars and the crashing fall of theidol of Mammon are shown.

Details showing how the picture wasmade are shown in the accompanying il-lustration. The two main sets that werebuilt comprised the tank and the interiorof the temple. The tank was much largerthan the type ordinarily used for suchscenes, and consequently had to be speciallybuilt. It is made of concrete, and wasequipped with several reservoirs, to beused for sluicing huge volumes of waterinto the scene. Wind machines wereplaced at numerous advantageous pointsto agitate the surface of the water, andhoses and rainfall pipes overhead wereused to increase the impression of the in-undation. Hundreds of men and dozensof horses struggled in the flood, or foundmomentary safety upon the "prop" rocksor portions of the reconstructed templewhich were placed in the tank. To addto the flood, troughs and spillways werearranged at advantageous positions bothin and around the tank. All views takenin the tank were supplemented with stockviews of clouds and sky photographedon rainy days.

The temple set was over 100 feet long,and more than half that width. Therewere steps leading down into the sunkenfloor.

The climax of the flood is the completedestruction of the pagan city. The crowdrushing toward the camera was separatelyphotographed and superimposed on thisview of the miniature city and inundation.

The entrance of the animals into the arkis also visualized in the photoplay. Onebeholds them coming from all directionsin a long shot in the film. In part thisshot was miniature (background) andpart real animals (foreground).

"Noah's Ark" as it 'was actually built fortaking the motion picture of that name.

Note the elephants in the foreground.

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How to Have Talking Movies(Continued from page 522)

Next arrange a method for putting yourmovie screen in front of your loud speaker.Having done this, you have merely to set theprojector in position when you are ready toshow your first "synchronized" films.

And now as to the actual filming and "syn-chronization." You have your choice of threekinds of sound effects, the first of which re-quires practically no preparation or appara-tus other than that described above, with theexception of an appropriate phonograph rec-ord. One advantage of this method is that youcan add a musical score or "theme -song" toany film you may now have, by merely play-ing the record chosen (via the pick-up)through the radio speaker, and at the sametime projecting the film on the screen, whichis in front of the speaker.

For example : in a love scene one mightuse "Kiss Me Again" or "I Can't Give YouAnything But Love," or any one of a thou-sand records that seems to fit the occasion.

Suppose you have a Spanish picture. Mu-sic from "Carmen," such as the "ToreadorSong" or "In a Little Spanish Town" mightgive just the proper touch.

A variation of this method is one that Itried when I first started experimenting withamateur talkies. I bought a wig and somegrease paint, and having seen Al Jolsonmake up as a black face comedian in his latestpicture, I proceeded to make myself up tolook as much like him as possible. Aftermuch rehearsal I put Mr. Jolson's record ofthe song "Sonny Boy" on the phonographand sang the song in accompaniment with thewords on the record, going through all thecharacteristic gestures and emotions. Allthis time I was being filmed. After the filmhad been printed, I projected it on the screen,and at the same time played the recordthrough the radio amplifier. Approximatesynchronization was easily obtained by ad-justing the speed of the motor, and I had asrealistic a talkie as any amateur could de-sire.

The second sound effect possible with thisapparatus is that of straight talking. Thesimplest way of producing this is to preparea short talk-a joke-a few introductory re-marks of some kind-or what you will.Memorize this, word for word, and reciteit slowly and distinctly before the camera.

When projecting the finished picture onthe screen, simply repeat the words into yourmicrophone, following the motions of yourown lips, and voila-you have a talkie !

Of course, two or more persons may be ina film of this sort. If so, it is advisable, butnot essential, that each one have a separatemicrophone in which to speak his part ; un-less a very sensitive one, similar to thoseused by broadcasting stations, is at hand.

The third method of applying sound ef-fects to a film is a combination of the othertwo ways : namely, to have musical accom-paniment and at especially dramatic momentsto have the actors speak their parts, as isdone in so many of the latest professionalfilms. It is an easy matter to switch fromvoice to music or vice versa. When youwish to talk, merely close the microphoneswitch. If you are using a desk type tele-phone, just pick the receiver up in order toclose the circuit. As soon as you have fin-ished talking, the opening of the switch willautomatically cut the pick-up into the circuitonce again. This effect is possible becauseof the difference in the electrical resistanceof the pick-up and the "mike." When theswitch is closed most of the current goesthrough the latter, as electricity alwaysfavors the path of the least resistance. Uponopening the switch, the "mike" is no longerin parallel with the pick-up, so the current -again flows through the pick-up.

October, 1929 Science and Invention 555'

Repairing Wooden ClockWorks

(Continued (ruin page 522)

A few pieces of cherry wood, a few piecesof wire, and a small piece of brass, andsome twine, is practically all the materialthis clock movement was made of. It wasmade in Winchester, Connecticut, at theclose of the eighteenth century. It wasworked out patiently by hand with a pocketknife and a few crude country tools, and itwas put together by the man who made it, acarpenter.

It was essential in those days to make aprospective customer depend upon a clockto tell time by ; that was in those days a sortof first requisite. And there were others ofthe rugged farmers who had first to beshown that a "wooden mechanism.' wouldactually work.

There was hardly any machinery used-infact, none, almost to the close of the eigh-teenth century-in the making of thesewooden movements. The cutting of thewheels and the pinions and all the "gears"was done with a crude saw and a jack-knife.These were usually marked out with asquare and compass and then sawed out withas fine a saw as they could get or perhapsmake for themselves.

To put in a tooth in a broken wheel or torepair a pinion where there are leaves brokenout, it was always necessary to use somekind of hardwood-mahogany or oak. Thewriter preferred to use fihre for its flexibil-ity ; but he mended this clock more easilythan many others, lesser repairs, by usingplastic wood-wood in a can, in the form ofa paste that can he moulded any way youwant, as easy as putty, and which in a fewhours hardens into wood.

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When Fate Fooled HoudiniBy Dunninger

(Continued front page 505)audience as the mishap is immediatelycovered up in some fitting way or manner.

A Close Escape in Mid -AirDURING the filming of the "Grins

Game," in which picture you willrecollect Houdini jumps from one planeto the other, hundreds of feet in the air, torescue the beautiful damsel from theclutches of the villain, the scene almostcaused the master mystifier his life. Nosooner had Houdini jumped from theplane which flew about twenty feet abovethe other one than the machine began todip, something had gone wrong, and thetop plane crashed down on top of theother one, which held the aviator, theleading woman and Houdini. Cameramen.actors and the director held their breaths.flow was it going to end? Quick thinkingcameramen continued to grind so a last -

.....111.11.1111111.11111.1.1...1111".1111111111%.wee

',at'

Houdini, handcuffed behind his back,leaping into river; second photo showshim coming to the surface with the cuffs

in his hand.

ing photographic record of that big mo-ment was preserved. And thanks to thegrit, quick thinking and steady nerve ofthe aviator, the actress and Houdini nosine was injured, but all of them receivedthe shock of their lives . . . except Hou-dini who was used to thrilling situations.for wasn't this sort of nerve-rackingbusiness part of his game? "It was agrim game, all right," said Houdini as hehelped the rescue crew untangle theaviator and the actress when the planesreached the ground.

An adventurous soul was Houdini. Hetook chances no one else would. Thereis a story told of this master of thrillsthat took place while he was returningfrom Australia. The steamer was in theshark -infested waters near Suva, in theFiji Islands. There is a supposition inthose parts that sharks, no matter howdeadly and ferocious, will not touch ablack man. So runs the tale and throughbelief in this more or less foolish fancy,native men and boys, without a thoughtof fear, dive deep for the coins throwninto the water by tourists. Houdini stoodagainst the deck rail with a number ofother passengers and watched the antics


of the native divers. Noticeable amongthe divers was a young fellow who seemedto always come up out of the water withthe coin, thrown by one of the men orwomen, in his mouth. Much talk wasindulged in about this man's remarkablediving ability, but Houdini, who had beenwatching him closely for some time, de-clared that the man dove into the water,grasped the coin with his hand and thenput it into his mouth. Others disputedthis but Harry finally wagered that ifthe diver's hands were tied behind hishack, which would not interfere withhis diving, that he (the diver) could notcatch the coin in his mouth as he wassupposed to have been doing right along,Furthermore, Houdini would allow him-self to be handcuffed and dive off the shipand would return with a coin in his mouth.

Members of Houdini's company didn'tcare to have an experiment of this kindtake place, but the master of magic de-cided that what he said was to be so. Andso it was. The captain warned Houdinito watch out for sharks, as they weren'texactly playful. The native diver wascalled aboard and an interpreter explainedwhat he was to do. The black diveragreed.

Houdini got into his bathing suit andbrought from his stateroom a pair ofhandcuffs. The black fellow's hands weretied behind his back while Houdini wasmanacled. Two forms hit the water to-gether after two coins were tossed over-board. A wait of a minute and the black'shead appeared. Ile needed air. A halfminute later, feet first, Houdini made hisre -appearance. The diver didn't have hiscoin but 1 loudini had both the coins inhis mouth. He won the bet but handedboth the coins to the diver for histrouble.

)id you see any sharks?" asked att,st-iiger. "Didn't I heave into sight

quick enough?" asked the handcuff king.-1 es, but why feet uppermost ?" "Well,replied I foothill, "I was deep down underthe water with one of my hands released.1 grabbed both the c. ,ins and shot theminto my mouth. It had to be done quicklybecause it would have been anything butpleasant to get a mouth full of that water.Then I spied a shark. It was a large,ferocious looking thing. So I shot my-self upward with as much force as I couldmuster. But I remembered I didn't putthe cuff back on my wrist so I shotaround and came up feet first which gaveme the required fraction of a second toreadjust the cuff." "A great stunt," re-marked a bystander. "Not at all," re-plied Houdini, "I did it because I wantedto have those Fiji Islanders know I wasas good a swimmer as they !" "Ilut thechance you took !" exclaimed another eye-witness, "My business is full of chances,and what would life be without its hun-dred and one thrills !" made answer theworld-thriller-Houdini.

The Mystic Handcuffs'O\E afternoon Houdini, and myself

were visiting a theatre owner of ouracquaintance, when Harry brought out apair of steel handcuffs and started totoy with them. Knowing he was up tosome prank we called in the special officeron duty at the house. As he entered the'room Harry made a pass at him and en-circled his wrist with a handcuff, lockingit as he did so. The officer was surpris, dfor the moment hut recognizing I I outli!'iand ourselves, laughed and told the hand

-

cuff king he would now have to teach himthe secret as to how he could release himself. Harry laughed and told him he'dcall around some other day and see ifhe had gotten out. Suddenly the specialofficer somehow slipped the cuffs from his

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wrists and handed them to Houdini say-ing, "Here. Open them." Houdini tookthe key from his pocket and opened thecuffs.

Quick as a flash the special officergrabbed the key and the cuffs and slippedthem on the manacle wizard's wrists,pressed them home and snapped the cuffsshut.

"And now that I have the key, let's seeyou get out of them, Mr. Houdini,"laughed the officer.

"Place the key on top of that desk," in-dicated Houdini, "and I'll see what I cando."

No sooner said than done. The key wasplaced on the manager's desk and im-mediately Houdini turned around, tossedthe cuffs on a typewriter desk and pickedup the key.

To the consternation and surprise of usall the officer picked up the handcuffs andthey had not been slipped from the wristsof Houdini, but had been unlocked!

I have time and again witnessed Houdiniescape from packing cases and trunks inas short a time, as it takes me to readthe mind of some skeptical fellow in theback row of the top gallery. I was alsopresent at the wizard's water burial, inwhich he outdid the much -heralded fakir,who first introduced the stunt. I truth-fully believe that had Harry Houdinilistened to my plea not to attempt thatfoolhardy stunt, he would yet be mysti-fying folks with his own full -evening'sperformance. He was in none too goodcondition when he attempted the testas he was complaining, now and then, ofa pain in his side.

Houdini had many imitators. Therewas never a tight corner that Houdinicouldn't escape from, but his imitatorsweren't so successful. One in particular,I won't mention his name, remains vividlyin my mind. This fellow was trying hisbest to out-Houdini Houdini. It waspitiful the extremes he went to in his effortto try and do this. One evening I wit-nessed his show and the funniest moment,vet most dramatic it was to myself as Iknew what he was trying to do as well asknowing what might have happened, waswhen this copyist was trussed up in afifty -foot length of rope from which hewas unable to free himself.

I had gone up on the stage at the be-ginning of the act with a friend, to actas one of the committee, but had nothingto do with the actual tieing of the per-former.

If it were possible for me to do it Iwould have helped the unlucky fellow outof his predicament, but I wouldn't havestood a chance with the other men, whohad challenged him that night. I spoketo an assistant, "Cut him out.' I whispered.The assistant disappeared around the backof the cabinet. Suddenly the would-beHoudini stepped from the cabinet free ofthe ropes. The escapeologist walked overtoward me and said in guarded tones,which only my friend and I could hear,"Thanks, Dunninger ! I'm glad you helpedme by tipping off my man. I was in adevilish mess!" Next day I received byexpress the length of cut rope with acard reading: 'No more lies, no moreties I'm going to do magic by and by !"And the card was signed by . . . well, he'sa good magician too . . . . now!

Was Houdini ever stuck with a pairof handcuffs, was he ever fastened intoany instrument of restraint, from whichhe failed to liberate himself ? These ques-tions have been asked by almost everyonewho ever knew or came in contact withthe wizard of escape. To those intimate

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with Houdini, would come a thought ofan experience which he often related. Ithappened in London, England. The DailyIllustrated Mirror, an English paper ofprominence, had challenged Houdini toescape from a pair of handcuffs, whichhad been made by a Birmingham black-smith, and which, it was said, had takenfive years to perfect. Houdini had ac-cepted the challenge, and a committee rep-resenting the newspaper brought the cuffto the handcuff manipulator, upon thestage of the London Hippodrome, wherean audience of over four thousand peopleawaited the much heralded event. Boththe pressmen and Houdini asked friendsto step upon the stage, to form a com-mittee to see that fair play predominated.

Those of my readers who witnessed thework of Houdini in any of the theatresthroughout the nation, will undoubtedlyrecall the speed and ease with which hewould free himself from all kinds ofmanacles. Ten or twelve handcuffs would belocked upon his arms at the same time.Houdini would kneel on the floor, anda small cabinet would be placed over him.The curtain would be drawn so as toconceal his hands, but not his face.Usually, it would take the escape wizardabout two minutes to free himself fromall of the irons.

But upon this fatal night, fate had de-cided differently. After the lone pair ofirons securely embraced the wrists ofHoudini, he retired into this cabinet, orlittle ghost house, as he called it, leavinghis committee anxiously awaiting results.Gracefully, the clock of time ticked on.Five minutes passed . . . then ten . . .

fifteen and twenty. . . . The audienceanxiously awaited results. Finally,Houdini's head peeped from out the ghosthouse. "He is free" shouted many in theaudience. They were, however, sadly dis-appointed. Houdini, still handcuffed,merely examined the locks beneath theglare of the footlights. With saddenedface, he re-entered the cabinet. Heavyperspiration trickled from his face. Heseemed worried, worn and uncomfortable.He asked that a pillow be placed beneathhis knees, as they were beginning to hurt.The request was granted by consent of thenewspaper's representative. Twenty min-utes more elapsed . .. the orchestra playedon, and once more, Houdini emerged fromthe cabinet. He was still handcuffed. Ap-proaching his challenger, he asked that thecuffs be removed for a moment, so as toenable him to remove his coat. This thejournalist refused to do, stating that hewould not unlock the cuffs, unless Houdiniwould admit defeat. He explained thatHoudini had seen the cuffs locked, but hadnever examined them unlocked. Conse-quently, he thought that- his reason forrefusal was obvious.

Houdini became somewhat angry. Hemaneuvered until he succeeded in remov-ing a penknife from his pocket. This hesucceeded in opening with his teeth, andturning his coat inside out, he proceededto cut the coat into pieces. Houdini oncemore entered the cabinet. Time sped on,and presently the timekeeper announcedthat Houdini had been in his cabinet, andunsuccessful in liberating himself, for onefull hour! Ten minutes more of anxiouswaiting . . . and out came Houdini, hold-ing the shining handcuffs in his hands.One hour and ten minutes had the wizardof escape nervously labored with one lonehandcuff. The strain had been so great,and his disappointment in the length oftime that he had labored, so keen, that heburst into tears. Houdini did succeed,but he had been stuck . . . and badly, too,and he never forgot this episode.

(Watch for the next article in the De-cember issue.)

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Making an Air Lift PumpBy L. B. Robbins

(Continued front page 524)

combined area should equal the cross sec-tion area of the pipe itself-about 1/2 sq.inch. Below these slits drill two holesthrough the pipe at right angles to eachother and drive through two steel pinsslightly less in length than the diameter ofthe eduction pipe. These act as spreadersto prevent the air pipe from blowing intoone side of the larger pipe. Do not makethem so long, however, that they will jamwhen lowering or raising the air pipe in orout of the eduction pipe. When this iscompleted, lower it down into the eductionpipe and thread on more lengths until thecap strikes the bottom of the strainer.Then measure carefully and cut off theair pipe and run on a thread at least 6 in.long so it can be threaded up through thetop section of the flange coupling and pro-ject an inch or two above it when seated.With that done let the coupling sectionscome together and bolt them in place tomake an air and water -tight joint.

Then pipe the % in. pipe to the outlet ofthe air pressure tank with an elbow andvalve as shown, using Y4 in. pipe for thepurpose.

The pressure tank can be purchased forthe purpose or can be made from a hotwater heating expansion tank or even ahot water boiler. The two latter, however,should be tested for pressure and anychancy ones discarded. Whatever style ofpressure tank is used, it should be suppliedwith a pressure gauge and a safety valvewhich can be purchased from any steamsupply company. The diagram shows themethod of piping.

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The DriveAS suggested, a small gas engine can be

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avoid slipping as the load becomes quiteheavy when considerable pressure has ac-cumulated in the tank.

A small one-horse power engine builtover in this manner should be able tocreate all the air pressure necessary. Aregular air compressor can be purchased,of course, if desired but is not necessaryif this idea is resorted to. Now, with theengine running and the compressor fillingthe air tank, you are ready to raise water.

OperatingTURN on the valve at the well -head

slowly. This will admit pressurethrough the nozzle slits into the water ofthe well. The natural outlet for the waterthus put under pressure will be up throughthe eduction pipe. As it rises, more willrush in to take its place and, with a con-stant stream of air flowing into the bottomof the pipe under sufficient pressure thewater will gradually rise until it flowsinto the tank above ground. A little ex-perimenting will soon determine the properpressure to admit to get the best flow ofwater. The valve can then be marked forthe number of turns necessary to open sothe right working pressure can always bereleased into the foot piece.

Do not be surprised if air rises with thewater as that will he perfectly natural un-der the circumstances. The great beautyof such a system is that there are noworking parts to become filled with silt orforeign matter. This will all be forced tothe surface and hence it would be wise toput a strainer in the supply tank outlet toprevent any dirt from entering the watersystem in the house. When necessary thewater pressure can be released by meansof the drain cock in the well -head as de-scribed.

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TECHNICAL AND INDUSTRIAL COURSES0 Architect El Automobile Work0 Architectural Draftsman 0 Aviation Engines0 Building Foreman IIJ Plumber and Steam Fitter

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New Nine Tube A. CReceiver

(Continued front page 535)in this particular speaker instead ofpaper. and a closed center replaces theopen center fiber construction. Flexiblevelvet is used for the outer suspension.The speaker is an entirely new develop-ment.

In the circuit diagram figure 1, is thehum control for the OF -227 tube. Thisis a twenty -ohm resistor. Figure 2 is thepilot lamp; 3, is the motor plug; 4, linesupply plug, and 5 is the hum control forthe CX-226 tube in the first audio stagewhich is a twenty -ohm resistor. Figure6, is the transfer switch which makes itpossible to change from the radio to thephonograph. Figure 7, is the record vol-ume control, a 500 -ohm resistor. Figure8, is the tone control which is a one-megohm resistor. The power switch isshown at 9.

An induction disc motor and a 12 -inchturntable are placed in the top portion ofthe cabinet. A new electric pick-up is usedand is mounted on the end of a straightpick-up arm which replaces the usual tone-arm. By the turn of a switch it is pos-sible to change from radio phonograph re-production in a second's time. The phono-graph records are reproduced through theaudio end of the radio receiver as shownin the circuit diagram. The instrumentwill operate from 105 to 120 volt, 50 to 60cycle alternating current lines and specialequipment is available for operation on 105to 120 volt, 25 to 40 cycle alternating cur-rent supply.

Engineering Taughtby Movies

(Continued front page 492)transformer. By means of these animatedmovies, the building up and the collapse ofthe lines of magnetic force in the field ofa transformer or a motor are clearlyshown in such a way that the student willnever forget the action so illustrated inpicture form before his eyes. The di-rection of an electric current in a certaincircuit is indicated very clearly.

$5,000 FOR PERPETUALMOTION

The editors have received thousands ofdifferent designs of perpetual motion de-vices, and have received hundreds of cir-cular letters soliciting finances for thebuilding of perpetual motion machines.

The editors know that if they receivethese letters, there are thousands of othersin this country who get similar lettersand who fall for the claims made in thenumerous prospectuses giving the earningcapacities of the various machines.

Most of the shares of stock for theseperpetual motion machines are being soldat a rate of $1.00 per share, although someinventors are trying to sell shares ofstock at $100.00 per share.

Therefore, the editors of this publica-tion say, "Just come in and show us-merely SHOW us-a working model of aperpetual motion machine and we willgive you $5,000.00. But the machine mustnot be made to operate by tides, winds,waterpower, natural evaporation or hu-midity. It must be perpetual motion."

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What Our Readers Think(Continued from page 533)

run next year myself, but if my saw badnot been dull and some of the teeth out,I could have qualified for one this year orsomething just as good.

A college education is the most wonder-ful gift a father and mother can give achild. I could spend time writing wholepages upon the good my High School andone year at Indiana University have donefor me. Everyone who succeeds musthave a college education or its equivalent.The equivalent is the hard and stonypath. A college education gives one atrained mind. The education I have hadhas enabled me to fit in anywhere andeverywhere at this country club, to adjustmyself to all situations-to meet peopleand please them, to work with the helpin the kitchen, to make every motion count.To work, work, work with my hands andat the same time anticipate with my brainthe next step. You can get there if youpersevere, college education or no collegeeducation ; you can also go to SouthAmerica by going to Canada and Europefirst. Why not take the direct route?

MRS. B. H. FREELA ND.120 E. 2nd St., Peru, Indiana.

(Perhaps some girl who has made goodwithout a college education, will now writeus and tell us how she overcame the handi-caps possessed by the college educatedgirl. We admire Mrs. Freeland's will-ingness to help. We feel sure that anywoman with as much spunk will succeed.The spirit "I'll make good in spite of all."is of keener metal than any "saw withbroken teeth" and has the peculiar prop-erty of becoming sharper with use.

We wish you, and others who think asyou and carry their thoughts into action,much good luck. You have our everywish for success.-EDITOR.

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To be sure of getting your copy each month,subscribe to SCIENCE AND INVENTION,$2.50 a year. Experimenter Publications, Inc.,381 Fourth Avenue, New York City.

Science and Invention

Answers to ScientificPuzzles


Balancing a BatIf a baseball bat is balanced on a knife-

edge, it will be found that the greaterproportion of the bat will be on the thickend. But while the weight is unequallydivided the moment, or leverage of bothportions is the same. This is because theheavier portion is closer, on the average,to the pivot, whereas the lighter portionis farther away.

Half Covering the Objective ofa Telescope

Covering a portion of the objective ofa telescope will not restrict the field ofvision because each part of the lensfocusses all of the light that passesthrough it and each part receives lightfrom all parts of the object. The imagethat we see is formed from the overlap-ping images formed by all of the separateparts of the lens. The only effect thatis noticed, consequently, is a diminution inintensity of the image.

The Sliding WeightsAccording to Newton's laws of motion

a body will accelerate in proportion to theapplied force and inversely as the massaccelerated. Since the masses acceleratedare 30 lbs. in both systems it follows thatthe acceleration of the systems is proportional to the applied force. In one casethis is 20 lbs. and in the other 10 lbs.Hence the first system will acceleratetwice as fast as the second.

When we consider the tensions in thecords we find that this is the force re-quired to accelerate the bodies movinghorizontally. The tension in one case ac-celerates a 10 lb. mass just half as fastas the tension in the other system accele-rates a 20 lb. mass. Since the productof the masses and their respective ac-celerations is the same it is evident thatthe tensions producing these accelerationsmust be the same.

Moist Air, Dry Air and AirPressure

It is common knowledge that a lowbarometer usually precedes foul weatherand a high barometer precedes and ac -1companies fair weather. This indicates,that moist air is actually lighter than dry'air, other conditions being the same. The'explanation of this is that as moisture'enters the air it displaces other com-1ponents, notably oxygen and nitrogen.Now an oxygen molecule is nearly asheavy as a water molecule and a moleculeof nitrogen is a little less than one ofoxygen m weight. Consequently an in-crease in water vapor means a decreasein density of the air,, whereas a decreasin water vapor is accompanied by a reof the heavier components and thereforean increase in density. Moist air is lighterthan dry air.

Icebergs Salty?Icebergs are not salty. In the first

place they are formed originally fromglaciers that slide down into the ocean andbreak off in huge pieces. Glaciers are'formed from snow, falling on elevationsfrom the sea. In the second place, ice -Ibergs are not salty because when saltwater freezes it is only the water thatfreezes out from a dilute solution such aswe find in the ocean. If the ocean weresaturated with salt the salt and ice might

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Balancing the Teeter -toterTo balance the teeter -toter the square of

Lettie's weight must exactly equal thesum of the squares of the weights of theother two girls. The problem, then, is tofind two whole numbers the sum of whosesquares will equal 102 squared. A straight-forward tho somewhat tedious way to dothis is as follows. Double the number(i.e. 102) Subtract one and to this num-ber add a number that is two less thanwhat you got after subtracting one. Thenadd a number that is two less than whatyou added before and keep on in thismanner until the last number that youhave added is 1. Now look over the seriesfor perfect squares and all numbers foundto be perfect squares will be solutions ofthe problem. In this case there is onlyone solution as the only perfect squaresthat appear in the series are 2304, 8100,and 10404. Thus we see that the weightsof the other two girls must be 48 and 90lbs. respectively. The beginning of theseries that leads to the solution is asfollows:

102 X 2=204 and 204 - 1=203203201

404199

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Winding WatchesIf a watch is wound at night the sub-

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Negative Plates Get HotThe negative plates of a lead storage

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A NEWEdition

Thoroughly revised - greatlyenlarged and offering awealth of new up-to-the-

minute information.

THERADIO

MANUALRevised Edition

Complete new chapters on aircraft radio equip-ment; Practical Television and Radiomovies withinstructions for building a complete outfit; radiointerference; 100% modulation; latest equipmentof the Western Electric Co.; the Marconi Auto -Alarm System; and many other developments ofthe past year. All this information is added in thenew edition and, besides, the entire book has beenbrought right up to date with much new material.The Radio Manual continues to be the one completeand up-to-the-minute handbook covering the entireradio field.

A CompleteCourse ina SingleVolume

20 big chapterscover: ElementaryElectricity and Mag-netism; Motors andGenerators; StorageBatteries and Charg-ing Circuits; TheVacuum Tube; Cir-cuits Employed inVacuum Tube

Transmitters; Modulating Sys-tems and 100% Modulation;W a v e -m et e r s; Piezo-ElectricOscillators; Wave Traps; Ma-rine Vacuum Tube Transmit-

ters; Radio Broadcasting Equipment; Arc Trans-mitters; Spark Transmitters; Commercial RadioReceivers; Marconi Auto -Alarm; Radio Beaconsand Direction Finders; Aircraft Radio Equipment;Practical Television and Radiomovies; EliminatingRadio Interference; Radio Laws and Regulations;Handling and Abstracting Traffic.An immense amount of information never beforeavailable including detailed descriptions ofstandard equipment is presented.

Prepared by OfficialExamining Officer

The author, G. E. Sterling, is Radio Inspectorand Examining Officer, Radio Division, U. S.Dept. of Commerce. The hook has been editedin detail by Robert S. Kruse, for five yearsTechnical Editor of QST, the Magazine of theAmerican Radio Relay League. Many otherexperts assisted them.

Free ExaminationThe new edition of "The Radio Manual" has lust

been published. Nearly 900 pages. 369 illustrations.Bound in Flexible Fahrikoid. The coupon brings thevolume for free examination. If you do not agree that itis the best Radio hook you have seen, return it and owenothing. If you keep it. send the price of $6.00 withinten (lays.

Order on This CouponD. Van Nostrand CO., Inc.,250 Fourth Ave., New YorkSend me the Revised edition of THE RADIOMANUAL for examination. Within ten days afterreceipt I will either return the volume or send you$6.00, the price in full. (S & I 10-29)

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DRAFTING

Learn at HomeDRAFTING is one of the best professions ayoung man can choose because it pays goodsalaries and it is the stepping stone to evenbetter positions. Many leading architects,mechanical engineers and electrical engi-neers got their start at the drafting board.

There is no easier way to learn Draftingthan through the home -study courses of theInternational Correspondence Schools. Thepractical value of these courses is shown bythe success of I. C. S. students and also bythe fact that employers are constantly writ-ing us for trained men. We receive morecalls for I. C. S. draftsmen than for gradu-ates of any other course.

F. E. King was "a poorly paid clerk" when he en-rolled for the I. C. S. Drafting Course. By study,industry, and perseverance he became Chief Drafts-man of the U. S. Steel Furniture Company, of Syra-cuse. He is now earning more in a day than he usedto earn in a week.

A. J. Hutchins became Chief Draftsman for theAmerican Strawboard Company and increased hissalary 300% -also as a result of I. C. S. Training.

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Einstein's Theory(Continued front page 550)

L.-Wouldn't it also be possible to ex-plain these effects by assuming that thatautomatic brass -band, there in the center,has a gravitational repulsion on the ball?(Fig. 3)

R.-Yes, indeed. Now let's experimentby moving around. Look! Here, at theoutside edge of the merry-go-round theball gets into motion more quickly thanit does when we were near the inneredge. This proves that the force, be itcentrifugal, attractive, or repulsive, ismore powerful the farther we are fromthat brass -band. But it does not say whatcauses it. It might even be magnetic orelectrostatic.

P.-I guess you're right. I can't seethat there is any way to decide betweenthe various possibilities.

R.-If I had the surrounding scenepainted on canvas mounted on a turn -tableand then revolved the turn -table back-ward, you would get all the thrill of themerry-go-round-even though it be mo-tionless (Fig. 4).

P.-Here, let me have that piece of rockwith string attached I saw in your suitcase.case.

(Relativist hands it over.)P.-(demonstrating). If I swing this

in circles about my head it is quite obviousthat there is a force acting. I can feelthe pull of the weight.

R.-What is more, you can measure theamount of the force. Here. Tie the otherend of the string to this spring balance.Now swing it. Yes, there is a force often pounds registering on the pointer scale.(Fig. 5.)

L.-But I thought you just said thatthere was no force acting to produce thecircular motion of the planets about thesun. Here is circular motion-and yetthe force is quite real.

Fig. 5b-The mo-ment the scale isreleased and al-lowed to follow itsnatural pat h, thescale reads zero.

R.-The two cases are far from anal-ogous. Do you not recall the funda-mental principle of relativity ?-that anobject, left to itself, tends to pursue itsmost natural course through space-time,and that apparent forces arise only whenthe object is forced to deviate from itsmost natural course. If you think thestone is following its natural tendenciesyou are greatly mistaken. Let go of thespring balance. The stone flies off on atangent and the pointer, indicating theforce, snaps to zero. The force vanishes.

L.-But is that not just because thestone is flying off in a straight line? Thecentrifugal force acts no longer, but thereis still the force of gravitation. You havenot proved that that, too, has vanished.


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Home MoviesBy Don Bennett


Stopf32f22fl6f8f 5.6f4f 2.7f2f 1.5

Square10244842566431

.167.442.2

"f1.5 is the largest lens stop used incommercial practice, a lens with thatopening being available for amateur use.A lens with an aperture of f0.5 was oncemade in a laboratory but was commer-cially impractical.

"Two stops with which lenses areusually marked have been left out of thislist, stops f6.3 and 14.5. F4.5 is exactlydouble f6.3 and falls midway between 14and f5.6 while f6.3 is between f5.6 and f8.Thus if your exposure called for f8 andyou were using a graduated filter set sothat an increase of 50% in exposure wererequired, f6.3 would be the proper setting.

"Selection of the proper filter or theproper density on your graduated filter isnecessary in autumnal photography ifgood color values are required. The usualfilters, yellow in color, will subtract theyellow, making it appear almost white,and will bring out the red in a mediumgray tone, while the green will appearnormal.

"Amateurs who use color have a splen-did opportunity to test the color range oftheir cameras at this time of the year.There is one thing to remember, though,bright yellow usually reproduces aswhite, especially in very bright sunlight.Also, if your exposure is too great, colorfringing is liable to result. This is espe-cially true in beach scenes and the neutraldensity filter should be used as instructed.This neutral density filter is a thin graydisc of glass that reduces the exposurewithout affecting the color, except to im-prove it where strong light is present.

"The proper care of your filters willassure a long life, whereas lack of carewill result in dirty, streaky pictures and apossible breakdown of the filter material.Gelatin filters, whose only reason for ex-istence is their cheapness, must not behandled with the bare fingers. The sweatand oil present on the surface of yourfingers will cause minute portions of thegelatin to dissolve and lose their filtervalue besides serving to distort the pic-ture through refraction. Glass filtersshould be kept in a soft envelope offlannel or chamois so they cannot becomescratched and they should be wiped offwith lens tissue before use.

"You have your choice of several waysof mounting your filters, you can use thesquares with a suitable helder to clampover your lens; the cells, which are roundand have spring sections on the side toclamp them to the lens, and with thegraduated filters, a tension mount thatpermits you to use any section of the filterat will.

"My advice to you is to take an ex-posure meter, a few filters, some panchro-matic film and your camera, go out insearch of color and experiment. That isalways the best way to learn."

(Next month's article will describe thepreparations for a Halloween movie partythat will amaze your friends. Simpleanimated cartoons and a big surprise willbe described.)

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We're glad to send a set to yourhome to examine and use as yourown for 15 days-to show youthat here Is the most up-to-dateand complete work on Electricityever published. Written byCROCKER of Columbia U.-MILLIKAN of Calif. "Tech."-HARRISON of General Elec-tric and 26 other noted ElectricalEngineers. Starts off with ele-mentary Electricity in simple,non -technical language for thebeginner and includes everyEngineering branch for use ofexperts on the job.

Complete Electrical Reading CourseElectricity, the biggest industry in the world, continuesto grow the most rapidly. And it offers better jobs,bigger salaries and a brighter future than any otherfield. Every dollar, every hour invested in learning Elec-tricity will come bact to you a thousand -fold. Learn inspare time with these books at one -,fifth the cost of trade

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Grow New Plants WithoutAny Seeds

By Dr. Ernest Bade


are usually taken, a number of them tiedinto a bundle and the bundle sunk into theground in a shady and moist spot. Theyare usually placed about four inches intothe ground.. The California privet whichis so much used for hedges is propagatedby this method. The cuttings are madein March and they are placed in a trenchone next to the other. Then an inch layerof moss is placed in the trench and thiscovered with soil. When the soil is dryit must be watered.

Berry Bushes

BERRY BUSHES may also be multi-plied by this method. Here one year

old shoots are cut about 'A a foot lengthby winter pruning. The shoots are bundledand hung in a frost free room or cellaruntil spring. Then they are taken out ofdoors and placed in the soil, spacing abouta foot apart. All buds with the exceptionof the upper .two are removed, the cuttingsbeing planted so that only these two budsprotrude. These cuttings will soon growprovided the beds are kept free from weeds.

Shoots of currants may be cut early inthe spring before they are in leaf andplanted. Layers are made from goose-berries. That is, a branch is taken, agirdle cut in the bark about T/8 of an inchin width, and the twig, with its girdleplaced a few inches into the ground, thetwig being held in position with a hooksunk into the ground. A few monthslater the twig sunk into the ground willhave rooted and it may be cut from themother plant and transplanted.

The barberry, another plant much usedfor hedges is most easily propagated bysinking a few branches into the groundand leaving a few months. Then thesebranches will have rooted and they maybe cut off. Each of these branches thenforms a new plant.

Tradescantia, an ornamental plant, pro-duces roots so easily that it is only neces-sary to place it in contact with moist soil.

New Plants from Leaves

IT is not even necessary to use a twigfor producing a new plant, sometimes

it is sufficient to use a leaf. Such leafcuttings are even used by the gardeners.At times not one plant, but three or fourmay be formed by a leaf. Take the caseof Bryophyllum calycinum. After cuttingoff a leaf near the petiol the cut surfacemust be left to dry. Then a few notchesare cut on the veins at the margin of theleaf. When the leaf is somewhat witheredit is placed in a flower pot containing asandy soil which must be kept moist. Aglass plate covers the pot and this tendsto keep the temperature and moisture con-tent in the pot as uniform as possible.Soon roots will be formed at the notchesand small leaves will make their appear-ance at these points. The large leaf actsas a storehouse of food for the undevel-oped plants and when they are capableof growing themselves the old leaf diesand a number of new plants is the result.

The leaf of the Begonia rex may betreated in a similar manner. But here theveins are cut at a place where two veinsjoin. If the plant is grown in a green-house. the leaf need not be cut off themother plant. New plants form at the cutveins and may be cut off after they havedeveloped sufficiently to be potted.

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Education

Coal Miner's Job SaferThan Yours!

By Alvin F. Harlow(Continued from page 507)

jeopardizing not only their own and theirfellows' lives but the mine's chances ofwinning honors in various safety contests.

Meanwhile the Bureau of Mines as wellas some of the large operators are issuingcirculars which hammer constantly at thesubject of hazard and prevention. Thesecirculars are full of pictures illustrating"Dangerous Practice" and "Safe Prac-tice"; posed photographs show in vividstyle how the heedless miner is caughtunder falling masses of rock, crushed be-tween car and wall, gets his foot caughtin a switch frog and is run over, walksalong a haulage track with an iron crow-bar over his shoulder, which touches thetrolley wire and gives him a fatal shock-and many other possible mishaps.

The Bureau even issues a Miner's Al-manac, with the usual day-by-day infor-mation about the sun and moon, whileabout half the space in the columnsusually given over to historical dates isfilled with crisp remarks on safety, healthand sanitation-hints on ailments of chil-dren, care of the teeth, malaria and mos-quitoes, drinking water, flies, physicalexaminations at regular intervals, warn-ings against patent. medicines, venerealdiseases, sanitary housing, mine gases, dustand ventilation, importance of learning theEnglish language and so on.

Superintendents, foremen and bosses areconstantly being stimulated and instructedin safety by bulletins and circulars, byvisitation and by district meetings andschools. An unusual agency for dis-seminating safety information is found inan iron mine at Eveleth, Minnesota, 215feet below the surface-a moving pictureauditorium where once or twice a week,at the noon hour, the men are shownsafety propaganda films, the show alwaysending with a bit of comedy.

The Bureau of Mines maintains safetystations in all the great mining districtsof the country, and likewise a number ofso-called Mine Rescue (railroad) Cars.These cars arc manned by experts insafety and rescue work and are ready at amoment's notice to rush to the scene ofa great disaster; but their principal func-tion and the one to which they are happilyable to devote most of their time is thatof going from place to place, spreadingsafety propaganda and instruction. Tenthousand miners are being trained annu-ally in first aid work and the use of gasmasks; and a much larger number arereached by lectures, demonstrations andpublications.

Safety committees composed in part orwholly of the miners themselves are doingimportant work in conserving life andlimb. In addition to committee recom-mendations, some companies request sug-gestions from individuals. The Bureauof Mines makes the startling statementthat "one of the largest concerns receivedin two years 5,200 suggestions . . . ofwhich 92 per cent were adopted. Anotherplant received 1.200 suggestions the firstyear. Of these, 90 per cent are nowoperative, 6 per cent are being investi-gated and only 4 per cent were rejected asbeing impractical."

Expert first aid and rescue work hasbecome an important feature of the in-dustry, being stimulated by numerousState, district and local contests. One bigsteel concern alone has in its milli andmines more than 22,000 employes whohave been trained in such work. Theskill attained by some of these amateur

EARLE LIEDERMAN-The Muscle BuilderAuthor of "Aluerle Building." "Science of Wreatling,""Secrete of Strength," "Beres Health," "Endurance," etc.

Kill This ManThere's a devil inside of you. He's trying to

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SavedThank your lucky stars you have another man

inside of you. He's the human dynamo. Hefills you full of pep and ambition. He keeps youalive-on fire. lie urges you on in your dailytasks. He makes you strive for bigger and betterthings to do. He makes you crave for life andstrength. He teaches you that the weak fall bythe wayside, but the strong succeed. He showsyou that exercise builds live tissue-live tissueis muscle-muscle means strength-strength ispower. Power brings success! That's what youwant, and gosh darn your old hide, you're goingto get it.

Which Man Will It Be?It's up to you-Set your own future. You want

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Sounds good, what? But listen! That isn't all. I'mnot just promising these things. I guarantee them! It'sa sure bet. Oh boy! Let's ride.

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EARLE LIEDERMANDept. 2710. 305 Broadway. New York City

Dear Sir: --Please send me, absolutely MIZE andwithout any obligation on my part whatever. a copy ofyour latest hook "Muscular Development." (Please writeor print plainly.)

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The Murder in the LaboratoryA notebook lay beside the poisoned body of

Sheppery, and in it he had scrawled a raggednumeral 3 before he died. It may mean some-thing-but what? Dr. Blythe, famous researchcritic, sets to work to prove some of his theories,and in so doing provides a story seldom equalledfor real thrills.

The Black Magician"Why did they kill him?" asked his secre-

tary. "Because ho forgot his glove!" was thecryptic answer from Secret -Service Smith, world-famous detective. But Smith was concerned, forhis traditional enemies had killed the man onthe very doorstep of his own home-and that de-manded vengeance! Another famous Secret -Service Smith mystery novel by R. T. M. Scott.

The Taxi MurderOn the side of a road they found him-in the

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The Latimer Murder CaseSergeant Barry Odell of the New York Policegoes on a winter vacation, and finds plenty ofwork to do. For the wealthy Mr. Latimer hasbeen found murdered in the snow, and all evi-dence points to his beautiful young wife. ButBarry never jumps at conclusions, and sets towork on the supposition that to prove a personinnocent, you've got to find another who is guilty.A real mystery novel that you won't drop untilit's finished.

The Ingram MurdersEight people were within 25 feet

of Amos Ingram when he wascruelly murdered in his own palatialhome. All of them could havedone it, but all of them seemedto have perfect alibis. Could ithave been the monkey? TomO'Shanter, daughter of the oldpolice chief, sets out to solve themystery, and runs into anotherstill more baffling. One of thosenovels that mystery fans rave over.See if you can figure out theguilty one.r

NOVEL MAGAZINE COMPANYDept. 2510XX, 381 Fourth Avenue, New York City, N. Y.

Gentlemen: I enclose $1.00 for which please send me, postpaid,the following 5 Complete Novels: "The Murder in the Laboratory,""The Black Magician," "The Taxi Murder," "The Latimer MurderCase;" and "The Ingram Murders." I understand that I can returnthese if not perfectly satisfied, and get my dollar back.

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teams is not surpassed by that of anyprofessional hospital staff.

In some mines underground first -aidstations are now being installed. Therooms have board floors, whitewashedwalls and electric light. One ingeniousidea is that of a galvanized cylinder,9 by 36 inches, containing a stretcher, awoolen blanket, a rubber blanket, severalkinds of bandages, gauze, cotton, anti-septics, drinking cup and a few simple in-struments and remedies. This is kept inthe station and can be used there orcarried to the scene of the accident.

One subject now being taught miners isthe science of walling themselves in byerecting gas -proof barricades across sideentries or dead ends when fires or explo-sions occur, and thus protecting them-selves until help can reach them. In theCherry, Illinois, disaster in 1909, twentymen walled themselves in thus, and wererescued after being entombed seven days.But recent years have developed a stillbetter idea, first used by some mines inthe Central States-namely, to build inthe main section of the mine occasionalrefuge chambers to which the men mayretreat in case of disaster and close them-selves in, the doors being gas -tight. Therooms are stocked with canned food andwater and air pipes are run into themfrom the compressor. The refuges al-ready in service have received practicaltests and have saved a number of lives.

The "Self Rescuer" is a new and valu-able device which enables men to maketheir way through the terrible after -damp or carbon monoxide following anexplosion. It is a little box -like affair nolarger than one's hand and is enclosed ina sealed container which may be hookedto the belt or carried in a coat pocket.If an explosion occurs, the miner appliesthe mouth and nose piece at the end ofthe device, and holding it in place withone hand, breathes through it. The boxcontains a chemical which changes carbonmonoxide to carbon dioxide-that is, itdoubles the quantity of oxygen in themolecule. With its aid a man can walkfor from thirty to seventy minutesthrough any percentage of carbon monox-ide likely to be found in a mine after anexplosion or a blast-which will in mostcases enable him to reach fresh air.

One company records on bulletin boardsthe important accidents to employes andpoints out the particular carelessness ordisregard of regulations involved. Theboard also announces that So-and-so wasdischarged for taking matches into themine or for jumping on a "man trip" ofmine cars after the train had started, inviolation of the rules. A miner enteringan employment office nowadays is apt tobe confronted by a large sign which reads:

SAFETY FIRSTUnless you are willing to he careful and avoidinjuries to yourself and fellow workmen, donot ask for employment. WE DO NOTWANT CARELESS MEN IN OUR

EMPLOY.

And when he goes underground he en-counters not only printed safety bulletinsbut perhaps a large "Safety First" ad-monition in electric lights somewhere inone of the main passages. One suchsign is located two miles from the en-trance in a mine in Idaho.

Not only by precept but by deed doesthe up-to-date mine management carry onthe movement. The physical appearanceof the modern mine would be a revela-tion to a medieval coal -digger. If itenters a hillside in tunnel fashion it is aptto have a trim -looking concrete portal.Sometimes the men enter by a similarportal quite separate from the main en-trance into which the car tracks run.

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a corresponding tenon on the post and thetwo parts are glued together.

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inch iron pipe should extend through theentire length and stick above the topabout three -eighths of an inch. Bothends of this pipe are threaded and a nutis screwed on the bottom end, and counter-sunk in the base. A screw socket is turnedon to the top end and the whole is heldfirmly together in this manner. With thelarger lamps all that is necessary is todrive a short piece of pipe, threaded atthe top, into the upper end and screw thesocket to it.

The hole for the cord and pipe shouldbe bored with a 34 -inch bit. Pipe sizesare always given in inside diameters, anda %-inch pipe has an outside diameter ofY8 of an inch.

Several holes should be cut or bored inthe bottom side of the base and meltedlead should be poured into these. Thissame thing should be done to the candlesticks and the vases also, or the articleswill be top-heavy. Another method isto screw a disc of lead to the bottom ofthe fixture, covering this with felt. A holeshould be bored from the side of the baseto the center for the cord, as one of theillustrations shows.

The finish and the shade will dependupon furniture and fittings. Lacquers andenamels give a bright touch that set asmall article like this off to advantage.The present very popular pleated shadelooks well on this style of lamp and theycan be purchased ready-made for a smallamount.

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The cups for the candles are bored witha N -inch bit to a depth of about 3.i -inchin the square block before turning isbegun. The dead center is used at thisend and centered at the bottom of thehole. Only in this way can a true holebe secured without danger of splitting.Brass cups to fit candlesticks can be pur-chased and placed in these holes. Theyare not necessary, however.

Turning a VaseWHEN one thinks of a vase he ordi-

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To make this vase, secure a test tubeof the desired size, bore a hole in the

INDEX TO ADVERTISERSPAGE

AAdams, John T 559Airplane Spruce Co 555Allied Radio Cor oration 576American Sales Cpo 556American School, The 481-558American School of Aviation.. 562American School of

PhotograVay 556American Technical Society. 560-568American Telephone & Tele-

graph Co 553Anita Institute 566Audel & Co., Theo.

Inside Back CoverAviation Institute of U. S. A 563

BBarawik Co., The 553Batenburg, P. J. F 557Bernard & Heller 550Blackstone, Inc., Richard 564Bliss Electrical School 573Bureau of Inventive Science 550Burns School of Wrestling 556

C

Campbell Co., Wm 566Chicago Salvage Stock Store 489Coleman, Watson E 548Conn, Ltd., C. G 546Coyne Electrical Scholl 583Crusader Apparatus Co ...... 558

13

Deagon, Inc., J. C 558-564Delta Specialty Co 557Detroit School of Lettering 555Dobe, Fred'k 559Douglas, Lyle 566Dryer, Prof. J. A 555Dynamic Mfg. Co 564

While every

PAGE

Encyclopaedia Brittanica, Inc. 487Evans & Co., Victor J 551Excello Products Corp 573

FFederal Mail Order Corp....544-558Federal School of Illustrating 547Ferry & Co 542First Hawaiian Conservatory

of Music, Inc 571Fisher Mfg. Co., Adam 550Franklin Institute 571

HHart Tire CoHigh Frequency LabsHigh School Home Study

BureauHobart Bros. CoHonigman, AHoodwin Co., Chas

565546

567564-567

861566

Ideal Aeroplane & Supply Co.,Inc. 568

Inkograph Co...........Back CoverInternational Correspondence

Schools 542-562-566International Heating Co 572

J

Jiffy-Tite Mfg. Co 564Johnson -Smith & Co. 566

KKelsey Co., The 559

LLacey and Lacey 550Lancaster & Allwine 550Landon School, The 556LaSalle Extension University

564-572

precaution is taken to insure accuracy,occasional change or omission in

PAGEL

Lederer School of Drawing 565Leonard, A. 0 544Liederman, Earle 569Lincoln Airplane School 558Lyons Mfg. Co 544

MMead Cycle Co 562Merriam Co., G. & C 544Metal Cast Prolucts Co 565Midland Tire & Rubber Co 564Miller, Carl 548Munn & Co 548

NNational Automotive &

Electrical School........... 553-558National Industries 568National Radio Institute 485National School of Meat

Cutting, Inc 556National School of Visual

Education 560New England Mills Co.

Inside Front CoverNew Method Mfg. Co., Inc.. 550-561New York Electrical School 555New York Institute of

Photography 556

0O'Brien, Clarence A 549

pPacific Technical University.... 554Pan-American Band Instrument

& Case Co 552-568Payne, R. S 568Pathfinder Co 565Piccadilly Hotel 544Plapao Labs., Inc 568Plymouth Rock Squab Co 559Polachek, Z. H 546

PAGEp

Process Corporation, The...... 566Publishers' Classified Service.. 561

RRadio Institute of America.... 541Radio Training Ass'n of

America 543Randolph & Co ... 548Ray, E H, 554Red Bug Bay 563Roat & Lohman 552

SSchool of Engineering of

Milwaukee 561.569Shure Bros. Company 565Speed Cleaner Co 561Speedo Mfg. Co 573Studebaker Corporation of

America, The 545Supra Value Shirt Co 544

TTamblyn, F. W 544Tarbell Systems. Inc 573Teleplex Co 562Thomas, C. M 573Thorola Radio Products 571Townsend Labs 564Tenor Banjo Studios 567

UUnited E.iterprises, Inc 555Universal Plumbing School 567

VVan Nostrand Co., D 565Vibraphone Co., Inc 567

Western Radio Mfg. Co.... 446-564Whirlwind Mfg. Co 571Wollensak Optical Co 554

we cannot guarantee against the possibilitythe preparation of this index.

of an


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wood selected to the proper depth for thetest tube, turn the wood either by using acone center in the hole or by plugging itup and cutting it off to length in the lathe.By the latter method a little extra lengthmust be added to the depth of the holeto allow for cutting off the plug end.

The ornamental vase will prove to berather a difficult turning project becauseof the hollowing -out process. A blockof wood large enough to make the vaseis secured to a center screw face -plate,the inside is hollowed out and then theoutside is turned. Of course water mustnot be used in it.

Bore a half hole for the cord in the base,by boring in the joint between a scrap of

wood and the bottom of the base.


Einstein's Theory(Continued from page 566)

R.-I beg your pardon, but I have. Thisscale makes no distinction, whatever be-tween centrifugal and gravitational force.As long as I hold the scale in my hand,the gravitational force is plainly indi-cated by the weight of the object. When Irelease the rock and scale, and the pointerreads zero, I have proved that both forceshave vanished. Your statement that theobject, on leaving my hand, moves in astraight line, is entirely incorrect. If Icould throw the rock from me with suffi-cient force, it would escape from the earthentirely, and revolve about the sun in anorbit of its own-an independent planet.

Fig. 6). That the index of the attachedscale continues to point at zero is finalevidence that no force acts on the planets.

P.-But if no force acts, why do theynot move in straight lines?

R.-They do, practically.P.-Now [ know you're talking non-

sense! We can plainly see that the orbitsare elliptical.

R.-You are speaking about their three-dimensional special orbits. I was refer-ring to their four dimensional space-timepaths. The planets are moving in geodes-ics, which is the nearest thing, in fourdimensional geometry, to a straight line.

L.-But why are the special orbitscircles?

R.-That is due to the presence of thesun. whose mass warps the space sur-rounding it. If you must have a picture,try to imagine space as an extensive plain,with a tremendously high hill in the cen-ter. That hill represents the sun. If, atraveller, in going through the country(Fig. 7) avoids the hill ( l'ath ABC ratherthan going over it A ) you do notascribe his apparent deviation from astraight line to attraction or repulsionfrom the hill. Even in our somewhat im-perfect analogy, the path ABC may he theshorter, though to an observer, who can-not see the mountain, it might nut appearto be so. Although we are unable to seethe hump in space around the sun, it ex-ists nevertheless. And the Einstein theory,as I said before, is simpler than Newton'slaw, because no attractive force of mys-terious origin is required.

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..,...OPPORTUNITY AD - LETS

, 0. will find many remarkable opportunities and real bargains in these columns. It will pay you to read and investigate the offeringsI made every month by reliable firms, dealers and amateurs from all over the country. No matter what you may be seeking, whether sup-

plies, automobile accessories, the opportunity to make money, or anything else, you will find listed here the best and moat attractive specialsof the month.

Advertisements in this section fifteen 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.

Objectionable or misleading advertisements not accepted. Advertisements for the December issue must reach us not later than October 1st.EXPERIMENTER PUBLICATIONS, INC., 381 Fourth Avenue, New York, N. Y.

All

AdvertisingGet into Advertising. Learn quickly at home. Experi-

ence unnecessary. New. easy plan. No text -hooks used.Practical work. Old established school. Send name andaddress for interesting free booklet. Page -Davis Schoolof Advertising. Dept. 533-A, 3601 Michigan, Chicago.

Advertising A genciesInch Display, 50 Monthlies, Thrice, $3.00. Meyer

Agency. 4112 R. Hartford. St. Louis. Mo.

Agents Wanted$60-$200 a week. Genuine Gold Letters for store win-

dows. Easily applied. Free samples. Liberal offer togeneral agents. Metallic Letter Co., 441 B., North Clark,Chicago.

Big Money applying Gold Initials on Automobiles.Easiest thing today. No experience needed. $1.45 profitevery $1.50 lob. Free Samples. "Ralco," R1043Washington, Boston. Mass.

$10 daily silvering mirrors, plating and refinishinglamps, reflectors. autos, beds, chandeliers by new method.Outfits furnished. Write Gunmetal Co., Ave. D. De-catur, Ill.

Agents-You can earn $12 daily wearing fine Felt Hatsand show to friends. Smartest styles. Latest shades. $2to $5 saving on every hat. Samples Free. Taylor Hat andCap Mfrs., Dept. PC -390. Cincinnati. Ohio.

Succeed With Your Own Products. Make them yourself.Formulas, Processes, Trade -Secrets. All lines. Catalog.Circulars free. D. Thaxly Co., Washington, D. C.

You Are Wanted to resilver mirrors at home. Immenseprofits plating autoparts, tableware, etc. Write Sprinkle,Plater, 955, Marion, Indiana.

Big Ohio Corporation wants county manager. Oppor-tunity $50 to $75 weekly. Earnings start immediately.Good for $5,000 yearly. We furnish everything. deliverand collect. Capital or experience unnecessary. Fyr-Fyter Co., 1907 Fyr-Fyter Bldg., Dayton, Ohio.

Gold Leaf Window Letters and Script Signs; no ex-perience; 500% profit; samples free. Consolidated, 69-R,West Van Buren, Chicago.

$12.00 Daily Showing New Tablecloth. Looks like Linen.Wash like oilcloth. No laundering. Sample free. Best -ever, 651 Irving Park Station, Chicago.

Make your own products. Employ agents yourself.Toilet articles, soap, extracts. We furnish everything.Valuable book Free. National Scientific Laboratories,1975 W. Broad, Richmond. Va.

Big money and fast sales. Every owner buys gold ini-tials 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.

Carter Window Washer. Cleans, dries, polishes-oneoperation. 10 sales daily nets you $420.00 monthly. Goodterritories open. Write today. Carter Products Corp.,971:1 Front Street, Cleveland, Ohio.

Agents making $40 week extra. Raincoats-$2.45. AllColors. Sample coat Free and bonus to Workers. Big Out-fit Free. Bradley, 228 So. Wells, Dept. ADIO, Chicago.

If you want to make $15 profit a day and get a new FordTudor Sedan free of cost, send me your name immediately.No experience necessary. Particulars Free. Albert Mills,3970 Monmouth, Cincinnati, Ohio.

Strange new electric iron cord! Prevents scorching.Saves electricity. Cannot kink or snarl. Used on tele-phones also. $25 daily. Samples Free. Neverknot Dept.10K, 4503, Ravenswood. Chicago.

Airplanes-A viationSimplex Air Model Co. Auburn, Mass. Send 5c for

supply catalog.

Biggest, Best Catalog Model Airplanes, Parts. Supplies;5c postpaid. Ideal Company. 23 West 18th Street, NewYork.

2e Postage Stamp brings you complete Model AirplaneSupplies Price List. A. A. C. Model Aircrafters, Dept.S. 340 East 188th Street, New York.

Sport Plane-Plans and data for building a light sportplane. All for $1.00. H. J. Boyce. Drumore, Pa.

Airplanes-Aviation (Continued)Propellers -1 ft., $8.75; 5 ft., $13.25; 6 ft., $16.50;

Special Henderson propeller, $15.00; Aerodrive boat orsled blueprints, 500 each. Helmets. $3.00. Goggles,$3.00; both only $5.00. Engines. Ostergaard Aircraft,4307 North Narragansett, Chicago.

Duraluminum Construction Set. Pursuit type, singleseater. Light speedy Flyer. $1.25 Pospaick Send livecents for Manual-teaches Building and Flying this plane.Foster's Model Airplanes, 5507 Hudson Boulevard, NorthBergen. New Jersey.

Mounted Propeller, 12 inch and circulars on 3 foot modelaeroplane, 10c. Aero Shop, 3050 Hurlbut Ave., Detroit,Mich.

Liberty Motor Generators, 12 Volts, new, complete,$7.50. Airplane machine gun telescope sights, 30 incheslong. $4.20, brand new. Air Transport Company, GardenCity, N. Y.

Books

Three BIB Wild West Novels In magazine form-all for50e-titles are "Gold," by Charles Snow; "Hell onWheels," by John Breck. and "The Border Wolf," byRobert Ames Bennett-all illustrated-all individuallybound novels. Send 50c for them to Mackinnon -FlyPublications, Inc.. 381 Fourth Avenue, New York, N. Y.

Five Popular Detective Novels in magazine formwritten by famous authors of mystery fiction-titles are-"Star of Death," by R. T. M. Scott; "The Secret De-fenders," by Anne MacMahon; "Stealthy Terror," byJohn Ferguson; "The Taxi Murder." by J. L. Byrne,and "The Marsh Murder," by N. B. Mavity-all five for asingle $1. Write to Mackinnon -Fly Publications, Inc.,381 Fourth Avenue, New York, N. Y.

Beauty Secrets worth hundreds of dollars-now yoursfor only 50c. A complete Encyclopedia of the art im-proves your beauty and personality by that famous BeautyCulturist. Eva Nagel Wolf. Large 9" by 12" book, withdozens of illustrations and over a hundred pages of help-ful, invaluable advice. Send 50c to Experimenter Pub=lications, Inc., New York, N. Y.

Business Opportunities

Sell By Main-Books, Novelties. Bargains! LargeProfits! Particulars Free. E-Elfco. 525 South Dear-born, Chicago.

Free Book. Start little mail order business. Hadwil,5A-74 Cortlandt Street, New York.

Learn Marbleizing and stone enameling concrete prod-ucts. Learn mold making all kinds. Resembles polishedmarble. Dime brings samples and illustrated literature.Cowell Institute, Grayling, Mich.

Make Money. Mail Order business your opportunity.Capital unnecessary. Information, instructions and 22 planscnly $1.00 postpaid. You need only ambition and thishook to succeed. H. Smith, 5616 Delorimier, Montreal,Canada.

Artists and Art Students are printing 250 signs andpictures an hour without machinery. Sample and par-ticulars 10e. Straco-1015 Mulberry, Springfield, Ohio.

Nickel -silver plate autoparts, silverware, Jewelry.lighting fixtures, metal cost 50c will plate work worth$9.00. Free laboratory baths. Big money evenings inbasement or spare room. Send stamp for samples, data.Lincoln Engineering Company, 855-A South 37th, Lin-coln, Nebraska.

Cameras and Photography SuppliesMake money in Photography. Learn quickly at home.

Spare or full time. New Plan. Nothing like it. Ex-perience unnecessary. American School of Photography,Dept. 5332, 3601 Michigan Avenue, Chicago.

Chemistry

Booklet of chemical experiments. Illustrated, 15c. General Chemical Company, Box 397, Reading, Penna.

Your Chemical problems solved and working processfurnished for Five Dollars. Write me. W. StedmanRichards, Consulting Chemist, Box 2402, Boston, Mass.

Correspondence CoursesUsed eorrespondence sahool courses sold on repurchase

basis. Also rented and exchanged. Money -back guar-antee. Catalog free. (Courses bought). Lee Mountain,Pisgah, Alabama.

Detectives

Detectives. Work home or travel. Experience un-necessary. Particulars free. Write George Wagner, 2190Broadway, N. Y.

Electricity

Electric Fun! Seventy stunts, 110 volts, $1. RuttingBros., Campbell, Calif.

EmploymentObtain employment desired, quickly, anywhere. Learn

how. Write Box 39-221, Station K, New York.

Engines, Motors, Dynamos

New 730 Watt, ball bearing generators $28.00; 1250watt, 32 volt lighting plants with engine, $169.75; % hp..32 volt motors, $9.75; 1/2 hp. General Electric, repulsion,a.c. motors, $27.00. All brand new. Write for bargaincatalog. Do not buy, consult us first. General Dis-tributing Company, Duluth. Minn.

For Inventors

For Selling Patents-Write to the Patent News, Wash-ington, D. C.

Get Your Own Patents, Legal Forms, complete instruc-tions $1. Cutting Bros., Campbell, Calif.

Inventors-We Build Models. Send us your rough idea.Our master mechanics will develop it for you into a prac-tical working model. Thirty years' successful experiencedoing this very thing. Best shop equipment. Expertadvice. Confidential service guaranteed. Bank referencefurnished. Send for free booklet, "The Road to Success."Crescent Tool Co., Dept. D, Cincinnati, Ohio.

Blanking and forming dies. Light stampings. Machinework. B. L. Nortwed. Mitchell, So. Dakota.

Inventors. Use our special service for presenting yourinvention or patent to manufacturers. Adam Fisher Mfg.Co., 205-A Enright, St. Louis, Mo.

FormulasHandy Formula Free. Send stamp. 10 additional

formulas, 25c. Satisfaction Guaranteed. Neil Taster,Shamokin, Pennsylvania.

Industrial Chemist furnishes formulas, processes; alllines. Moderate charges. Inquiries invited. Clore, Indus-trial Chemist, Box 152-H, Crawfordsville, Ind.

Help and Instruction

Be a Detective-Biggest paying work; everywhere.Write National Headquarters, 169 East 83rd, New York.

I Catch from 45 to 60 foxes in from 4 to 5 weeks' time.Can teach any reader of this magazine how to get them.Write for particulars. W. A. Hadley, Stanstead, Que.

Help Wanted-Instruction

Wanted Immediately, Men -Women. 18-55, qualify forpermanent Government Positions, $105-$250 month; ex-perience not required; Vacations with pay; common edu-cation; many needed soon. Write, Instruction Bureau, 293.St. Louis, Mo., quickly.


Playing With Death(Continued from page 509)

these have been grossly exaggerated.In one of the illustrations accompanying

this article, we see a man who chooses tofight with an alligator daily for the edi-fication of the audiences which crowdaround to watch him. They in turnrelish the battle; they like to see manconquer beast without the aid of science'smodern weapons.

From the standpoint of showmanship,a man capable of supporting two othersfrom a sword held on the back of hisneck and across his shoulders becomesanother interesting stunt. Should thesword slip in either direction, the man maybe severely cut.

Speaking of swords, we can turn toanother interesting bit of a thriller. Thisis presented in the following style. Aman loads an improvised cannon with asmall bit of dynamite. Naturally, whenthis cannon is fired, the recoil is quitegreat. In order to demonstrate to theaudience that he has a steady head, herequests an assistant to hold the point ofthe sword against the back of his neckwhile he in turn holds the cannon in hismouth. Here again, everything must bebalanced to a nicety.

Where a man loops the loop, in a specialapparatus supported by a second per-former, we find that not only is the exer-cise of daring necessary, but the effectcombines a certain amount of skill. Thesame is true of the German woman whochooses to jump out of the third storywindow for either motion picture con-cerns, or for the benefit of the public andin this way gains her livelihood.

In the October Issue of

AMAZING STORIESDEATH FROM THE SKIES, by A.Hyatt Verrill, is a unique story of ex-ceeding interest. Being an ethnologistand archaeologist of high reputation, Mr.Verrill must necessarily be conversantwith many other branches of science. Hehas proved his versatility a number oftimes, but he has outdone himself inworking out this interplanetary theme.

THE SECRET KINGDOM, by Allen S.and Otis Adelbert Kline. (A serial inthree parts). Part I. Do vanquishedraces really become submerged by thevictorious nations or otherwise disap-pear? It may be a comparatively simplematter keeping tabs on exiled royalty orleaders nowadays; but what happened tothe exiled rulers f the days before print-ing and wireless? Mr. Kline, who needsno introduction to our readers,! givessome theories on the subject in convinc-ing language and in a most plausiblemanner.THE CHAMBER OF LIFE, by G. PeytonWertenbaker. The author of "The Manfrom the Atom," comes back to us withan entirely new and original theme. Itis a well -written story, picturing a per-fectly ordered world.

THE STEAM GOD, by Walter Kateley,Geologic upheavals have created amazingchanges and developed strange conditions,many of which have been studied bygeologists. But there are still miles andmiles of unknown lands. What peoplesmight be living in uncharted ice -lands orinaccessible valleys? Mr. Kateley hasbuilt up a story of logical sequence con-taining much of scientific value.ONE LEG TOO MANY, by W. Alexander.This is still another in the series ofshort stories of unique development andoriginal interest which have appeared invarious issues of AMAZING STORIES.In it the author develops an ingeniousidea, which is not nearly as impossible ofrealization as may seem on first thought.

InstructionWant a Government lob? $1260-$3400 year. Men-

Women, 18-50. Steady. No "layoffs." Pleasant work.Paid vacation. Short hours. Experience usually un-necessary. Thousands 1929 appointments. 25 coachedfree. Full particulars Free. Write today sure. FranklinInstitute, Dept. B-4, Rochester, N. Y.

Men, women, everywhere. Manage your own business.Learn local advertising (distributing and supervising thedistributing of free samples, folders, circulars, etc., andtacking -up signs). Unlimited opportunities. No selling.Complete instruction one dollar. John Wagner, Box 457,Palo Alto. Cal.

Railway Postal Clerks, $158.00-$225.00 month. Steady.Examinations coming. Common education sufficient. Men18-35. 25 coached free. Write immediately. FranklinInstitute, Dept. B-15, Rochester, N. Y.

Inventions WantedInventions Wanted-patented, unpatented. If you have

an idea for sale, write Hartley, Box 928, Bangor, Me.

Inventions Commercialized. Patented or unpatented.Write, Adam Fisher Mfg. Co., 205 Enright, St. Louis,Mo.

Magic and GamesVanishing Coin Trick-Mysterious, bewildering. Amaze

your friends. 20c silver. Dana, 413-S Rose Place, LongBeach, California.

100 Card Tricks for 25c. Complete descriptions forperforming with dozens of illustrations-all in one bigeasy -to -read book. Amaze your friends with these featsof magic. Send 25c today to Experimenter Publications,Inc., 381 Fourth Avenue, New York, N. Y.

Cookoo Nuts. The fascinating new game that makesa party twice as much fun-only 25c complete. WriteExperimenter Publications, Inc., 381 Fourth Avenue,New York, N. Y.

Male Help. WantedSteamship Positions-Men-Women. Good Pay. Ex-

perience unnecessary. List of positions Free. W. E.Arculus, Mount Vernon, N. Y.

MiscellaneousAny possible help for all Sciences. References, etc.

Obvious Service, Unusual. F. L. Jones, 426, G. P. 0.,New York.

Brass Gears and Model Supplies-Send for Catalogue.The Pierce Model Works, Tinley Park, Ill.

Five Big Movie Novels all for $1. All individual novels,fully illustrated, in magazine form-same stories oftencost you $2 each in the stores, titles are-"The SingingFool," "The Awakening," "Noah's Ark," "Lilac Time"and "The 11W Dance." Send only $1 to Mackinnon -FlyPublications, Inc., 381 Fourth Avenue, New York, N. Y.Houdini Debunks Spiritualism. The master magiciannow describes how the spiritualist fools the public-allin this big, well illustrated book. Size 9" by 12"-112pages. Book complete, only 50c. Send for it today toExperimenter Publications, Inc., 381 Fourth Avenue,New York, N. Y.

Smatter Pop-the famous comic strip artist now bringsyou 50 comic strips all nicely hound in a colorful book.Price only 25c. Write Experimenter Publications, Inc.,381 Fourth Avenue, New York. N. Y.

Oil Oil I'm Leffing. The Jewish Joke Book that keepsthem laughing. Plenty of wise -cracks and plenty of fun-only 25c complete. Write Experimenter Publications,Inc., 381 Fourth Avenue, New York, N. Y.

MusicalPlay Piano by Ear. A Sound System, Booklet free.

Boucher's Harmony Studio. Box 12. Ottawa. Canada.

Patentsinventions Commercialized. Patented or unpatented.

Write, Adam Fisher Mfg. Co., 205 Enright, St. Louis,Mo.

Patent AttorneysPatents Procured; Trade -Marks Registered-Preliminary

advice furnished without charge. Booklet and form fordisclosing idea free. Irving L McCathran, 703 Interna-tional Building, Washington, D. C.

Monroe E. Miller, Ouray Bldg., Washington, D. C.Patent Lawyer, Mechanical, Electrical Expert. Bookletand Priority Record blank gratis.

Patents-Write for Free Instructions. Send drawing orModels for Examination. Carl Miller, Registered PatentAttorney (former l'atent office examiner). 258 McGillBuilding, Washington, D. C.

"Inventors' Guide" tree on request; gives valuable in-formation and advice for all who have original ideas orimprovements. Frank Lederman, Registered Attorney andEngineer, 233 Broadway, New York City.

"Inventor's Adviser, Valuable Patentbook sent free.Labiner. 3 Park Row, New York.

Patents-Send for form "Evidence of Conception" to besigned and witnessed. Form, fee schedule information free.Lancaster and Allwine. Registered Patent Attorneys inUnited States and Canada, 242 Ouray Bldg., Washington.n. C.

Inventions patented; inventions developed, correspondenceinvited; confidential advice; trade -marks registered; copy-rights. Edward Gottlieb, Patent Attorney -Engineer, 5Beekman Street, New York.

Patent Attorneys (Continued)Patents. Booklet free. Highest references. Best re-

sults. Promptness assured. Watson E. Coleman, PatentAttorney. Washington, D. C.

Patents. Time counts in applying for patents. Don'trisk delay in protecting your ideas. Send sketch or modelfor instructions or write for Free book, "How to Obtain aPatent" and "Record of Invention" form. No charge forinformation on how to proceed. Communications strictlyconfidential. Prompt, careful, efficient service. ClarenceA. O'Brien. Registered Patent Attorney, Security BankBuilding (directly across street from patent office), Wash-ington. D. C. See page 549.

Inventors who derive largest profits know and heed cer-tain simple but vital facts before applying for patents.Our book Patent -Sense gives those facts; free. Lacey &Lacey, 644 F St., Washington, D. C. Established 1869.

Patents WantedInventions Commercialized. Patented or unpatented.

Write. Adam Fisher Mfg. Co., 205 Enright, St. Louis, Mo.

PersonalLet me read your character from your hand -writing.

Sample reading, 12c. Graphologist, 2309 -BP, Lawrence,Toledo, 0.

Photoplays Wanted$ $ $ For Photoplay Plots, Stories accepted any form, re-

vised, criticised, copyrighted, marketed. Estab. 1917.Booklet free. Universal Scenario Co.. 223 Western & SantaMonica Bldg., Hollywood, Calif.

Photos, Pictures, and PostcardsMen-Samples, 20, $1.00 Sideline. Photo -G. P. 0., Box

471, New York.Free Book-"What men know about women." Humorous

and interesting. Kind men like. 10 snappy cards. Redhot pocket novelty. Copy America's greatest illustratedcartoon book. All for 25c. White Mule, Beaver Dam. Wis.

Printing Outfits and SuppliesPrint Your Own cards, stationery, circulars, advertising.

etc. Junior press, $5.90; job presses, $11; rotary, $149.Print for others; big profit. Easy rules furnished. Writefor catalog presses, type, paper, etc. Kelsey Company,Q-6, Meriden, Conn.

RadioLicensed Radio Doctors earn $75-$100 per week. Big

demand; investigate at once. Free Booklet. Radio Doc-tors, Inc., Dept. E. Essex St., Salem, Mass.

Get Commander Byrd's messages from the Antarctic-with a Short Wave Radio Set. Complete Short WaveManual with instructions for building and full size blueprints-all for 50c. Write today to Experimenter Pub-lications, Inc., 381 Fourth Avenue, New York, N. Y.

Salesmen WantedPunehboard Salesmen. $10,000 Yearly. New Line.

All fast sellers. Lowest prices. Full commission on re-peat business. Catalog Free. Maly! Puritan NoveltyCo. 1409 Jackson, Chicago, Ill.

Amazing screw -holding screw driver! Factories,garages, workers buy on sight! Profit 75c each. Ex-clusive territory. Free trial offer. Jiffy, 1177 WinthropBldg., Boston.

Sales PromotionAnything can be sold by mail. Banning, Tittles Bldg.,

ing, Watertown, N. Y.

Song PoemsSong Poem Writers: "Rent" Proposition. Hibbeler,

D191, 2104 N. Keystone, Chicago.

SongwritersFree! Song Writers' Guide. Beaver, D-24-1257 Elm,

Green Bay. Wis.Songwriters: Submit your song -poem or complete

song. Will return it immediately it not accepted.Chester Escher, Music Publisher, 125 W. 45th St., NewYork City.

Songwriters: Substantial Advance Royalties are paid onpublishers' acceptance. Write for free booklet on de-veloping ideas for song, words or music required byTalking Pictures. Newcomer Associates, 1674 Broadway,New York.

TelegraphyL Morse and wireless telegraphy. Big salaries.

Tremendous demand. Expenses low, can earn part.Catalog free. Dodge's Institute, Stone Street, Valparaiso,Indiana.

Wanted to BuyMail us your discarded jewelry, gold, crowns and

bridges, watches, diamonds, silver, platinum. Moneypromptly mailed. Goods returned if offer refused. UnitedStates Smelting Works (The Old Reliable), 39 So. StateSt., Dept. 3, Chicago.


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HAWKINS ELECTRICAL GUIDES3500 PAGES $1 A VOLUME4700 PICTURES $1 A MONTHKnow the facts in Electricity. They mean more money and betterposition for you. Hawkins Guides tell you all you need to knowabout Electricity. Every important electrical subject covered soyou can understand it. Easy to study and apply. A complete,practical working course, in 10 volumes. Books are pocket size;flexible covers. Order a set today to look over.

LEARN ALL ABOUTMagnetism-Induction - Experiments - Dynamos - Electric Ma-chinery-Motors-Armatures-Armature Windings-Installing ofDynamos-Electrical Instrument Testing-Practical Managementof Dynamos and Motors-Distribution Systems-Wiring-WiringDiagrams - Sign Flashers - Storage Batteries - Principles of AlternatingCurrents and Alternators - Alternating Current Motors - Transformers -Converters-Rectifiers-Alternating Current Systems-Circuit Breakers-Measuring Instruments-Switchboards-Wiring-Power Stations-Installing-Telephone-Telegraph-Wireless-Bells-Lighting-Railways. Also manyModern Practical Applications of Electricity and Ready Reference Indexof the ten numbers.

SHIPPED FREENot a cent to pay until you see the books. No obligation to buy unlessyou are satisfied. Send Coupon now-today-and get this great helplibrary and see if it is not worth $100 to you-you pay $1.00 a month forten months or return it.

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THEO. AUDEL & CO.65 West 23rd Street, New York City

Please submit me for free examination, HAWKINSELECTRICAL GUIDE (Price $1 a number). Ship atonce prepaid, the 10 numbers. If satisfactory, I agreeto send you $1 within seven days and to further mailyou $1 each month until paid.

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ReferenceS. 1. OCT

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AGENTS1-'"'

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FRPATENTED1, 21, 1925

ANSWERS the purpose ofpen and pencil combined!

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