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U- BOATS USE BALLOONS FOR WIRELESS SEE PAGE 74 E, IPP

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www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER i 3i . o r i EXPERIMENTERS!

Student's Chromic Plunge Battery This Is an Ideal battery for eleetrie.l ..pert mental work u'h, re . : r.:; L. net reignited TI, e ws

Iamb tor .stars] I nm a mall bay m,.. to tuna II I,rtr.gila nua w -rk; it I., oh al ha booing ark: It glues a fairly sl.aI)' rrrm and as the :Inc electrode can be pulled clear of the 'Wettable. nip materials are used when bat eery stands Idle. Bost Amalgam Zinc only tr mod! well a

a highly porous carbon m `.Iradier current. MY. furrdsls s ongh' chromic salt. for 4 chem... Fulh directlona fur rpnnnl and r ..r hatlery Inrind,J Ea -h batten- Iris : lolls and I. amlarrs wl,,a'. nl an byres slimlid be drawn from bam.ry i-,eninuou,1,l r., these batteries. o areat malty experlooros gun L I .11 run 1.111 of tills buttery If ul-w1 by 'Ideal. partible battery. Sire enrr all 1... 2 Fl11gdna w.. No. 999. Si t trot's ITrhonlr i'tunu. Hatter,. IMMEDIATE SHIPMENTS $0.50 The "Electro" Radiotone HIGH FREQUENCY SILENT TEST BUZZER This Instrument gives a wonderful Ideh pitchedpitched \II Sit'.t I, %oTe' in the rm' fstrs, to ohlain Willi thr rdinary lest buzzer. The RAOIOTIlNE 'Is built along entirely new line.: It is NOT an nrtneay hnurr, reconstrueted In some manner. The 'CAI/INTONE has single Ou steel reed sthrat lilR at a remarkably high spend. adjusted to Its most efficient frequency at the factory. Il and rl tern enti. lasts are Used to stake the Instrument last prarlicxl j' fnr.-v.r. \m. the RAIHOTINE Is SILENT. In fact, It is an silent that you must plate your war nn top of It to hear its beautiful muslea I note. You Will be astounded at the wnnderlIdly Clear 5.0 cycle nor snunnam shandy in your receivers. To learn the codes. there Is absolutelyy nothing Ilk. It. with the radlotone. a key and one dry cell and ANY telephone. a One learner's srt is bad. Two or more such sets in srrirs will attend no end of pleasure for Intercommunication work. Shipping Weight I lb. Iln,haone as leserihed eaeb 'IMMEDIATE SHIPMENTS The "Electro" Telegraph bórmrTawsm ua.nwhatsuM 'Waal 14111 EurrIttlatrr is not a toy. Inn a tracheal, honestly built telegraph out ft. eldch not only sounds lint works like We Mg won lll onest instruments By .rlutb'Ina Idle code for 30 days sal c u h-ob, ir s first -class telegraph operator. Huth operators are Ill big demand now. thrttit nhlsists of TWO complete Ielegraph Instru- ments eatIl Ill. amount 314 U. x 2.. All metal parts are highly tlekel plated. Including key lever. Note hard rubber knob. smewniffigfiB( Telegraph Code d'hart. telegraph blanks and -ul rting Wire a ,m es Willi set. huh o hadrrls. OutOt work, 1 on 2 dryd cells )nlone well for each Instrument I. The "Eleetro" Is the ONLY OuI RI That works both way, each Mallon can call: no menthes. no xt9ra[s .11 Nothing to get o at t f order. Guaranteed In ihaae you r money . hack. Price Campl:t as IPustrat,d (TWO INSTRUMENTS).. `$ L \n ShlyylIng 2 Ibs. 1 Weight. 1s -p- ,yI IMMEDIATE SHIPMENTS '6 INWWIiYIui. JJl ..0 t3 The "Electro" Codophone (Patent, I'e,rdinrl What this r e m rkable $1.50 Iadrument Is and does. No. FX2on2 The "Dec- o.," Cedo- BOY'S ELECTRIC TOYS" contains enough mate - phone is Yli¡nill `©J "E - Ix Ills ly the Trial TO MAKE AND COMPLETE OVER TWENTY :.: r i my t otril FIVE DIFFERENT ELECTRICAL APPARATOS with ut m a d e out any oilier loots. except a servo-driver furnished with the outfit. The box that will complete instruments and apparatus which are :dread, imitate a Sun contains the following crele ti o 1 r assembled: exactly as rim. Sludtyal's chromic plunge battery, rmniumssRUlrammieter, solenoid, lelephon.' heard in a I reeelver, electric lamp. Enough various parts. wire, etc., are furnished 1.. Wireless re- make the following apparatus: enet. T h c. 1 ud- tahkIii r cricrr (quieted xieh a horn, talks sr, 1 1 (list can hear Electromagnet, electric cannon. magnetic dancing spiral. electric you ii pictures, ths sound all tover the room. earn If there is a lot of ether noise. hammer. galvanometer, voltmeter, hook for telephone receiver. condenser, THAT'S NOT ALL. By Itsacnina or lightening the receiver cap. tone sensitive microphore. short distance wireless telephone. test storage battery. (non the lowest, nnfleat quarry. up In the loudest mol Walled screaming shocking coll. complete telegraph set. electric riveting machine. electric buz- sound tan be dad In I (Pis saiib. FOR INTERCOMMUNICATION. l'siva ton dry relia for each Instru- zer. dancing fishes. singing telephone. mysterious dancing man, electric jump- ment. when connected with one alre return I but- hsa Cedephoess and ground. _- ing jack, magnetic geometric figures, rheostat. erratic pendulum, electric can he used for mtrrromnnudeatluu hem, n h Incas.. on. -hall tulle snarl terfly. thermo electric motor, visual telegraph, etc., etc. One u 1 alt done riqlaies alit- oldfashiiitted l learner's aiegphl set, con. This does not be any means exhnnst the list, but a great many more ap- slating of key and sounder. The "Eltrlm" Cadephen is haudsonte. well made Instrument, fool 'meatus tau be built netulll' 91111 effectually. proof. and built for hard work. flutter, are of hard aliter is Inch in With the instruction lantk sxldrh we furnish, one hundred experiments that diameter. that mull outla.1 the tu strmntnt. caul be made with this outfit are listed. nearly all of these being illustrated There Is Alen a teal c,dr chart and full direction. enabling any Intent- with superb illustrations. No other materials, goods or supplies are neces- 0-nt ysung roan er girl la learn the cedes within 30 des,. [damming sary to perform any of the one hundred experiments or to make any of Ili, liait hour a day. Slays: Gtr x 3 x 2'51'. Flpppina eight. 2 IM. 25 a ;pa rn t ils. Everything can be constructed and accomplished by means of Tho "Elertree' rodophnne ai described. coopere $ 1.50 this 011111(, two hands, and it screw- drh'er. The outfit contains 114 separate pieces of material and 24 pieces of finished "The Llrest Catalog In America" articles ready to use at once. Our Ilg. new elrttrlcal evelnpc,ii a No. 19 I, nailing for you. l'iwit ltely finished following are Included: Chromic sa os the moo complete Wireless and electrical Cal alet in print attar. 22a Btu Among the material the parts 'tilo 500 socket, wire (two different lengths/. l'aura. Imprimons, Instrlinteiis and pparatus etc ltla Treath, for battery. letup bottle of nicretly, core an Wlyd.,, Telegraphy." 20 FREE (mum.. for ale 160 -paie FREE Wire. a bottle of Iron filings. three si Is of wire. carbons. a quantity- of nurhlne Hiss t'nur.t' lu ,II Ii -.. e. FREE l'yelorssIla ' Nu la nu awns 7x Si,'. ffill screws, flexible cord, two wood bases, glass plate, parafilue paper. binding tt'ridil 1j lh. Iteautlf IR (suers. posts, srrtlrdriver, etc.. el e. The Ilistrurlloil bunk Is so clear that anyone can r1 aaw =IN 11 drake the apparatus without trouble. and besides a section of the Instruction I a hank the layman it taken up with the fundamentals of electricity to acquaint ELECTRO is with ull important facts in electricity in a simple manner. We guarantee satisfaction? 231 F 1 en s 111 almnl. C'n 1 W The size over all of the °mill Is 14 s 9 s 2%. Shipping weight, F Ibs. $5.00 .rr,1 _r 'I11,11 I TT Ir' lu,a dy'.Inprdia t'ala No. EX2002 "The Boy's Electric Toys." outfit as described ,7 It. m. : AP IMMEDIATE SHIPMENTS NA 231 Fulton St. SEP 8 98 ELECTRO IMPORTING CO., NEVV lORK t Ill .,TAT 4474,sny 7 M. " "7"' E. ..liìül. , ':ii: :1.0.1 _: tI Awe, or o..'n ow.; the "Etear:cal /Let..ronenfer' tchni rvihnq CO add cerise,..

www.americanradiohistory.com 738 ELECTRICAL EXPERIMENTER March, 1918

`4=w (.6_716

OLsF

YOUR COUNTRY NEEDS Airplane Mechanics and Aviators Young men contemplating entering the United States air ser- --i/'C%--- vice will now be able to obtain sound preparation under expert instructors of AIRPLANE MECHANICS and AVIATION

ENORMOUS DEMAND FOR TRAINED MEN

E have seen and heard much of the proposal of pupil') planes to be provided by the United States within the next year. In a country where one great "NV industry produces a million and a half motor cars per .ear, the fabrication of one hundred thousand planes might seem easy, but actual figures, based on three years of actual experience in the war, show that there are now between Pony and fifty men of the auxiliary services required for each active machine at the front. If the same ratio should be adhered to to our service, It would mean that some 1,uuu,00u men would be required in our aeronautical department on foreign soil between our ports of debarka- tion and the fighting front. " -Statement of Howard E. Coffin, Chairman of the Air- craft Production Board, in The New York Times, .lanuary 11, ISIS.

SCHOOL'S METHODS THOR- COMPLETE EQUIPMENT IS OUGHLY ENDORSED PROVIDED THE School was founded to meet an urgent F:RY Drunenance needed. t'r Instrurdnn e.d by former Arnp' and Navy men provided the school. A complete air- highest standing, who appreciated the re- E isPlane the sponstbility. Recognized as experts in the aria- airplane motors art provided and boa world, they planned the details of all equip- pupils are instructed concerning each pan and ment and instruction. The school has been brcesti- how to assemble them. Lew is gun instruction it gated by the technical journals and newspaper given with an actual Lewis gun. This enable. and thoroughly endorsed. Exert' applicant for tui- the Instructor to combine theory and pnrtice tion is presented with proofs of the school', which gires the pupil knowledge that readily be reliability before his enrollment is solicited. come- practicable when he leaves the school.

Besides the opportunity for service under the flag, AVIATION IS THE INDUSTRY OF TO -DAY, and after the war chances for advancement will be boundless. We prepare men for UNITED STATES ARMY UNITED STATES NAVY THE AIRCRAFT INDUSTRY Instruction given in airplane mechanics and aerody- Lewis Gun Instruction aviation officers who have had active included in namics under three service in France. Daily lessons (three hours), morning. CADETS' afternoon or evening. COURSE FLYING TAUGHT for men prior to going to ground school. Ctiprse also covers Engines, Pla ies,. ;46LE AV IATION.iCFtM Aerodynamics, Construe - tion, Riggings, etc. I t4 Weart 42d J'treet New YorK

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www.americanradiohistory.com Ellechca,_ x cmcnter 233 FUI.TON STREET, NEW YORK Publisht by Experimenter I'ubL.iu ng Company, Inc. Gernsback, III. President; S. Gern,1 Id, Treasurer;) 233 F ult.. Street, New York Vol. V Whole No. 59 MARCH, 1918 No. Il

U -MOATS USE iIALLOONS FOR WiRELESS Front Cover VISITING ARLINGTON VIA THE TALO From a painting by icorge Wall Ct.l'B t By W. J. Flowell 763 PRESIDENT'S SI'EECII TO w'ORLI) VIA CABLE AND RADIO 741 DESIGN AND USE OF THE WAVEMETEI4 CAN ELECTRICITY DESTROY GRAVITATION, 743 THE By Morton \V. Sterns 764 ELECTRICITY AND WAR IN TIIE "FILMS" 744 110W AND wily OF NAM() \PI'ARATUS TIME By W. Winfield Seem.. Assoc. I. R. E 766 ELECRIC WINTER COMFORTS 745 SOME NEW STATIC ENPERIMENTS 110W U -BOATS SEND RADIO 1,000 MILES By Frederick Von Lichtenow By II. \%infield ceor 74e, A SPEEDOMETER FOR SMALL BATTERY MOTORS 768 ELECTRIC BOILER MOST EFFICIENT 748 ELIMINATNG THE SMOKE NUISANCE Stanton C. Moore 770 BY ELECTRICITY M\- ELECTRICAL LABORATORY. (Special pri $S By William II e, THE FIRST TROLLEY By Walter Bock 771 Ilolmes 750 HOW TO MAKE A "BLINKER LIGHT" FOR MOTOR BOATS. 772 ELECTRIC POWER FROM THE \WIND 751 SIPHONS -HOW Tt1El' WORK WOMEN LEARN RADIO 752 By I. W. Russel and J L. Clifford 773 SEAPLANE CRASHES INTO RADIO TOWER 753 A SPECIAL GOLDLEAF ELECTROSCOPE FOR RADIOACTIVE JUMBO GETS THIS HIDE VACUUMED 754 EN PER] MENTS By J. L. Clifford 774 AN ELECTRIC SHELL FOR FIGHTING U -BOATS 755 AN AUTOMATIC ELECTRIC RAILWAY By Arthur Priebe 775 ANNUAL ELECTRIC LOAD RELIEF MAP RESEMBLES HOW- TO- MAKE-IT PRIZE CONTEST 776 "ROCKIES" WRINKLES. RECIPES AND FORMULAS..Edited by S. Gernsback 779 756 ENPERIMENTAI. CHEMISTRY AT WAR WITH THE INVISIBLE By R. and G. \Wintbiop 755 -22nd Lesson By Albert W. \\'ilsdon 780 EXPERIMENTAL PHYSICS - LESSON II - PHOTOGRAPHY, "ELECTRICAL LABORATORY"- Prize Contest CONCLUDED By John J. Furia, A. B., M A 76o 781 LATEST PATENTS DIGEST 782 RADIO DEPARTMENT 761 PHONEY PATENTS- CONTEST STATION IN 783 WIRELESS FRENCH TRENCH 7o2 QUESTION BON 784

L11LIJLIIJ:LIJL! EIRRIJJ:IA,AI 191fi1IAILIVI lit.. ï II 11J lJll J 1,1,111L AR.4111,1J11,.J#111,k Dormant Forces

URING the nast few months we have read them. All about us -in eery stole, in all metals, in L J a good deal in the daily press about a every piece of wood, every material in fact -billions of wonderful new force purported as having horsepowers are laying. locked up, dead and inert. The been discovered by an Armenian gentle- atomic energy locked up in a one -cent piece is sufficient man by the name of Garabed Giragossian. to lift up the Woolworth building several thousand feet " Garabed," as the new "force" is now into the air. The only trouble is we do not as yet know sop, lady known, is supposed to drive ships across the how to unlock this tremendous energy. We are still oceans at a fraction of the cost it is possible of doing blind towards atomic forces, just as blind as the savage he same thing now. Aeroplanes with a "handful" of is towards a cubic foot of Trinitrotoluol. It means Garabed will cross the Atlantic in a few hours, so we nothing to him, for he can kick it around to his heart's are told; in short, all our known notions of present -day content, without danger, and nothing will happen. Even energy- producers will be thrown on the ash- heap,- if we did supply him with the necessary percussion cap always providing that Mr. Giragossian will be able to it would not help him to unlock the 10,000 cubic feet make good his promise! of gas lung dormant in that one cubic foot of explosive. That the scientific press lias kept itself aloof -never He would not know how to apply the cap, which per- even mentioning the supposed invention- matters little. haps is a good thing -for he would never have to try Scientific men quite properly like to deal with facts, not it again -at least not after his relatives had discovered suppositious inventions. But Mr. Giragossian has been his remains, miles away from the scene! able to interest our Government, and at the present time Some of the newspaper editors have ridiculed Mr. five scientists of repute are looking into the merits of Giragossian, as they thought he meant perpetual motion l!1 the "discovery." Whether Mr. Giragossian has actually by his perhaps rash term of "free energy." These made a great invention or not is beside the scope of worthy gentlemen evidently forget that their fathers this article, The point we wish to make is that the some forty years ago talked in like ternis when the world. as far as cheap energy is concerned, still sleeps Niagara Falls were first spoken of to run the street cars the sleep of the ages. \Ve cannot even claim that the in Rochester and Syracuse-over 100 miles distant! world in that respect is still in its infancy. It is much All this of course is ancient history now, but it is further back than that-it has not even been born. simply a conversion of a natural power. and "free" \ \'hat are we to think of ourselves and our much - energy in a sense. For it costs niatn actually nothing; vaunted science when we contemplate the fact that, for the power is there, all we need to do is tap it. and we instance, when burning coal to produce electric light do not have to expend additional energy in so tapping we get 6/10 of 1% of useful light from the energy it either, as for instance we must do in mining and stored in our coal when we burn it, the other 99 4/10% hauling and handling coal. being totally lost in useless heat which we don't want. Of course, this tapping of our waterpower to -day is Just think of the tremendous energy we expend in first a barbarous procedure. one our grandchildren will laugh mining coal. then hauling it over a thousand miles of at; but for its it is as wonderful as 't was for our rail, then transshipping it a dozen times, re- loading forest ancestors when they tried labs "iously to make and unloading it before we finally drive an engine with a fire by rubbing dry wood sticks together. the little heat we can actually extract from the coal. But the new energy is coming as surely as the sun Is it not tantalizing to realize that the latent energy will rise tomorrow, and just as surely this force will stored up in % ounce of coal -theoretically -can haul make man free from most of his present physical a long train over one thousand miles! Atomic forces drudgery. are so gigantic that we cannot begin to even comprehend H. GERNSBACK. 11 l11J_1J_11 ;J 111 PAIL L!Jl, JP L11J_LI1JL 1\414J.4' L JL !J I 1! 1 J1i1

The ELECTRICAL EXPERIMENTER Is puhtshl on the 15th of each month st 2:13 Fulton Bons cannot 1w returned videos full footage has been 'minded. .\LI n,-u,pted court nhu Street. New fork. There are 12 nn1111W% per year. Subsrrtptbm prle.- Is $1.50 year In dons are Pahl for "n publication. \ rat, Is pool for novel experiments: nid U. S. sind possessions. Canada and forehri ruun tries. $2 00 a year. t' S. colt as well photographs accompanying them are ItAl,yieelal des, rablr. as 1'. 8. sumps Invented Ino foreign coins or stampa1. Small. copies. 15 rents earl,. .i Manille. Entered as and class at the asutpL copy will he set on rnluewt. Checks and money orders EI.RCTRItAI. EXl'ERISIFINTE:It matter grail. should he drawn to New lurk l',.ö Mire under Art ,a Cougrrss rf Starel, s1579. nslst crol l'. eviler of EXPERIMENTER 1'l. R1.1811I xa III.. INC. If you enema.. address Tide cone notify Patent Umre l'opyright. I:'10, by K. E. Co . toc.. New York. The Contents of TMs us promptly. In order thst nies are u"1 miseorrlyd or lost. A Brea. wrapper Ind leales explrallen. Na mgazlna are copyrighted and must not be reproduced without giving full credit to the espies sent after expiration. Publication. Ali ennmtunicatlnets end contributions to tins Journal should he &darest to: Editor. 'The E:I.F:ITRlt'Al. Exl'Enll1 ENTER 1s for sale at all newsstands in the United Slate, ELECTRICAL EXPEItI51ENTER. 233 Fulton Street. Nos York. l'useeepnV rontrtbu- and Canada; also at Ierentano s. 37 .\..1111e de ['opera. Paris. 739

www.americanradiohistory.com 740 ELECTRICAL EXPERIMENTER March, 1918

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The Only Way to Learn to be the only men that are fully quali- you will want to join the New York fied to satisfy EVERY demand of the Electrical School. It will be an advantage Electricity Electrical Profession. to you to start at once. Hurry and send The only way you can become an ex- At this "Learn by Doing" School a man for our 64 -page book which tells you all pert is by doing the very work under com- acquires the art of Electrical Drafting; about the school, with pictures of our petent instructors, which you will he called the best business method and experience equipment and students at work, and a upon to do later on. In other words, in Electrical Contracting, together with full description of the course - You need learn by doing. That is the method of the the skill to install, operate and maintain not hesitate to send for this book. It is New York Electrical School. all systems for producing, transmitting FREE to everyone interested in elec- Five minutes of actual practice properly and using electricity. A school for Old tricity. It will not obligate you to send directed is worth more to a man than and Young. Individual instruction. for it. Send the coupon or write us a years and years of book study. Indeed, letter. But write us now while you are Actual Practice is the only training of And Now thinking about the subject of electricity. value. and graduates of New York Elec- If you have an ambition to make a trical School have proved themselves name for yourself in the electrical field School open to eisilors 9 A. M. to 9 P. M.

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www.americanradiohistory.com ELEZTRI CFL EXPERI M EIrITEP

H. GERN 5 B ACK EDITOR H. W. 5ECOR ASSOCIATE EDITOR

Vol. V. Whole No. 59 March, 1918 Number 11 President's Speech to World Via Cable and Radio

to the ends of the earth used for the transmission, and the oper- kept tinder lock and key or under naval President Wilson's recent "Peace- ators at both ends were locked in their guard. Advance information would have terms" address was sped by cable, rooms lest by any chance there might be been almost priceless to Wall Street specu- telegraph and radio as soon as he a leak as to the nature of the speech before lators. began it, and thru the newspapers :Mr. Wilson delivered it. At thirty minutes past noon the word of every civilized country the whole world's Then, in order to insure absolute ac- came "Release President's speech," and the reading population has become acquainted curacy, the address was "read back" to cable and telegraph operators started click- with America's war aims in detail. Washington over a private long- distance ing it off to the four quarters of the globe. rÌ. ARCTIC OCEAN w.

ARCTIC OCEAN

NORWAY SWEDEN a, PET ROGRA NOME ICE AND

COPEN HA GEN

5T IRELANO MICNA HALIFAX LONDON \ NEWFOUNIMND

LISE JAPAN AZORE

TOKYO NEWYORK M UR. k NAGASAKI WASHINGTON D.G. HAWAIIANIS .-" SAN PHI PPINE 15. FRANCISCO/ CUBA a MI AY1. SANOIEGb CAPE RA .l PORTO Se RICO VERDE %S., 15. GUAM yyt PARA PANAMA Z`^ PER`AAM- ,' OR EC) FANNING I.- l t` FREETOWN SOIITit' ' á' JAVA L I MA. *A(gE1t1DA BR15%ATE COCOS 15\ } QUIQUE 1! 1 \ f) ASCENSION I. MAURITIUS I. N ¿ ..-. VALPARAISO % RIO OE ...- QACIF\IC JANEIRO INDIAN OCEAN FERN CUAN y9. /"w UNCRGROU40 JOHANNESBURG CABLE CA OWN AIRES5 ATLANTIC OCEAN AUSTRALIA SYDNEY NI W'ZEALAND

INDIAN OCEAN

Map of the World. Showing Principal Cables (Full Lines) and Land Lines (Dotted Lines) By Which President Wilson's Recent "Peace - terms" Address Was Broadcasted to Every Civilized Country as Soon as He Started Speaking at Washington. The Powerful U. S. Govern- ment Radio Stations at Darien and San Diego Flashed the Message to Ships at Sea and the Smaller Islands In the Caribbean.

This was one of the biggest and swiftest telephone. When it had been verified, it was -fo London it went by Western Union bits of news distribution on record. and it cut into "cable takes" of approximately 100 cable. There it was given to the Reuter. was done in this way: words each, and the operators who were to Exchange Telegraph and Central News The speech was telegraphed in advance handle it opened their keys and got ready agencies. which flashed it at once to all the the day before the President spoke, to the for the "flash" which would tell them to newspapers they serve. Via Western Division of Foreign Press of the Commit- start sending. The speech contained about Union cable the message flashed to London tee of Public Information at New York 2,700 words. Every one who had anything and \vas actually delivered in that city in 2 City. The Government's private wire was to do with the handling of the speech was hours and 35 minutes. Reuter's agency in 741

www.americanradiohistory.com 742 ELECTRICAL EXPERIMENTER March, 1918

AUSTRIANS USE RADIO IN ALPS. oil as indicated by the thermometers on of a square metal tube 4 ft. 8 in. (1.4 The Radio operator in active military transformers, the Pacific Power & Light metre) long and 2 in. (5 cm.) square. At service does not always have a hut or dug- Co. in one of its sub -stations has attached the ends are placed two mirrors facing out in which to set up his instruments. The periscopes to each transformer to enable each other at an angle of 45 deg. with the photo herewith illus- sides of the tube. trates a temporary The lower mirror is Austrian radio sta- 1i in. (4.8 cm.) tion near the top of wide and 3 in. (7.6 a mountain peak in cm.) long, while the the Alps. The small upper one is PA in. antenna nt a s t is (4.8 cm.) by 3% in. guyed in position as (8.6cm.) long. The shown and the op- upper mirror is erator at the foot made longer to give of the pole is busy a longer view of the receiving a message. thermometer scale. At the extreme right an officer is making ELECTRIC SHIP observations which HAS FUTURE. he reports to t h e The electric ship wireless man for is no longer a dream transmission to but a reality, and it headquarters. Note is quite possible that the two industrious within a few years radio squad men of the close of the kneeling down in the war every new ves- center of the photo. sel of any size will They are the "dyna- be driven. steered, mo men" and their stopt, reversed or duty is to turn the turned, merely by crank and spin the the pressing of a dynamo until the series of buttons on voltmeter registers the bridge. The ap- 110 volts. The op- plication of t h i s erator can then press principle will enable his key and send out ships to be run with h i s message. No the highest efficiency current is necessary at an even speed, for receiving t h e permit marine engi- messages. room © by neers more liberty cndenroad and Underwood Far Up In the Cold Mountain -tops, Thousands of Feet Above Sea Lev el, the Wireless Proves of design and yield Itself Invaluable. This Portable Radio Set Is Being Used by an Austri an Signal Corps Squad in the Alps Region. proportionately greater cargo space PERISCOPE FOR READING the operator to observe the temperature than the present cumbrous form of ma- TRANSFORMER TEMPERATURES. from the floor. This makes it unnecessary chinery allows. The newer American mer- In order to read the temperature of the to use step -ladders. The periscope consists chant ships are electrically controlled.

London also recabled it immediately to the It was sent to Australia by the British first place the modern atlas and geography American Ministers in The Hague, Stock- cable which runs from Vancouver, B. C., to "map of the world" does not show any- holm, Copenhagen and Christiania, thus cov- Sydney. It was telegraphed to San Fran- where near all of the cables now laid and ering Holland, Sweden, Denmark and Nor- cisco in the short time of I hour and 3S in successful operation in various parts of way. The Ministers gave out the speech minutes, and then cabled to Hawaii, to the world. as soon as they received it to all the news Shanghai (there distributed by Reuter's) Several interesting long- distance cable agencies in their respective countries. and to Tokio. where the Japanese agencies routes used in broad -casting the President's From London the speech was sent also -Kokusai and Nippon Dempo-sent it out. speech of 2,700 words to the world are to Petrograd and distributed to the news By cable the speech [vent by direct cable the following, and which were not men- agencies by a branch of the American Com- to Havana, Port au Prince, Hayti and Car - tioned in the newspaper accounts. In the mittee oit Public Information in the Rus- raccas, Venezuela. It also went via direct preparation of this article the editors have sian capital. From Petrograd it was tele- cable to Colon, across the isthmus to Pan- had the assistance of Mr. Donald lcNicol, graphed over land lines to Moscow and ama, and from there down the west coast Assistant Electrical Engineer of the Postal thence to Brest Litovsk, the scene of the of South America to Santiago. Chili, whence Telegraph Co., and Mr, Walter S. Rog- recent Russian -German peace parley. it was telegraphed across the Andes (over ers, Director of Foreign Press Division at To Paris the President's address was sent the longest under -ground cable in the New York. by way of the Commercial Cable in the world) to all the lower capitals of South The speech reached the "Far East" - space of 1 hour and 38 minutes. There it American republics, reaching Buenos Ayres India, Sumatra. Java. Ceylon (of Lipton was given out to the Havas News Agency, first. tea fame) and the Malay Peninsula by the Agencie Radio and the Maison de la From the naval radio station at Darien, cable. The message sped over the ocean Presse, the French official institution for on the Isthmus of Panama, the address was cables from Lisbon, Portugal, down along distributing news. These organizations for- flashed out.to all the little islands and ships the west coast of Africa, via Cape Verde warded it to Berne, to Rome. to Athens and in the Caribbean. The naval radio station Island, to Cape Town, South Africa. From to Madrid and Lisbon ; thus covering at San Diego, Calif., also flashed the mes- here it was telegraphed across country to Switzerland. Italy, Greece, Spain and sage to ships in the Pacific. Durban, on the east coast, and flashed on Portugal. The United States and Canada, of course, via Mozambique north to Aden, at the south News wires arc working between Berlin received it thru the ordinary news agencies end of the Red Sea, thence by cable to and the Holland border, as well as to the which supply both. Bombay, India. It continued from here by Swiss border. so the speech got into Ger- An idea of the speed with which the overland telegraph to Madras, on the east many certainly from one or another of speech was sent out may be had from the coast and. once more speeding under water. these border stations, (the message re- fact that Buenos Ayres reported back that reached Penang on the Malay Peninsula. ceived in Holland and Switzerland being it had been received in full one hour and Front Penang the message spread to the transmitted to the German border by forty -five minutes after the operators here several islands in the East Indies. An alter- courier, from which point it was telegraphed had stopt sending. Meanwhile it had been native cable route, but liable to interruption to Berlin) and doubtless was sent down retelegraphed across the mountains down in due to present naval activities in the Med- thru the Central Empires from Berlin. South America. iterranean Sea, lies along the coast of Por- South Africa and India receive their Many extremely interesting points were tugal front Lisbon, via Gibraltar. thru the news 'thru the Reuter Agency in England, revealed by this gigantic news propaganda Mediterranean, thence along the Suez Canal and the speech was cabled to them by that which the average person. who never uses route, thru the Red Sea cables. to Aden organization. the cables. knows but little about. In the (Continued on page 802)

BACK NUMBERSI -Many readers desire to obtain back numbers of this Journal. We have a limited quantity of these back issues on hand and can supply them at the followlnp rates: -Back numbers of The Electrical Experimenter not over three months old, 15 cents each; over three months old, 20 cents each over one year old, 35 cents each.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 743 Can Electricity Destroy Gravitation? 5 it possible to nullify, and further to Nipher supplies experimental evidence that of this bar evert reverse, the two small lead spheres of effect of gravity by gravitational attraction can not only be known mass. electricity? This scientific Two equal large balls of conundrum suspended or nullified by the electrical cur- solid lead are placed seems about to be solved, least close to the small at to a rent, but it actually can be transformed into suspended spheres certain extent. To begin tvith, every- "gravitational repulsion!" in the manner shown. Now, remembering our law of physics body is familiar with that law of physics All during the summer of 1917, Profes- stated which above -that every body in space at- states "that all particles of matter at- sor Nipper had his apparatus in almost tracts tract every other body proportionally to each other with a force which is their respective greater the nearer the particles masses and inversely as are to- the distance between them gether," and to be still more definite, New- -then it is evident that when this apparatus is set ton's law says that bodies behave as up, that if every the small suspended particle of matter attracted every spheres will be slightly other par- attracted by the larger, ticle with a force that is proportional to stationary balls. the This condition is represented product of their masses and inversely in Fig. 1. pro- Before connecting any form portional to the square of the distance be- of electric tween them. current to the modified Cavendish ap- It is the gravitational attrac- paratus, tion between the earth Prof. Nipher took special precau- and the bodies upon tion to carefully it which causes the latter screen the moving element to have weight. from any electro- This fact is often lost sight static or electromagnetic of and should effects. His apparatus be well understood by every briefly consists of student. To two large lead spheres make the matter more clear let its imagine ten inches in diameter, resting upon heavy that a man's body is .(as by flying, jumping, sheets of hard rubber. Two small lead balls, diving from a high point, each one etc..) for the inch in diameter were moment separated from the now suspended from surtace of the two silk threads, stationed earth. As soon as the mass at the sides of of the body is the two large lead spheres. separated from the earth, gravitational at- from which they were separated a little distance. Moreover. traction is set up between the two masses. the suspended balls were insulated The earth pulls the man's body, and also elabor- ately from the large spheres by enclosing his body pulls the earth, but as the mass them first airtight in a of the earth is infinitely greater, long wooden box. its move- which was also ment cannot be detected. covered with tinned iron sheets as well as cardboard sheets. The scientists of to -day believe that in There was, furtheremore, a metal some mysterious way the minute electrical shield between charges existing the box and the large metal spheres. The on the particles making up large metal molecules Prof. Francis lead spheres now exerted a and atoms are definitely linked E. Nipher, of the St. Louis certain gravitational up and concerned with such basic phenom- Academy of Science, Who Has Proved By pull upon the sus- Laboratory Experiments That Gravitation pended small lead balls as indicated ena as gravitation. Since all bodies are in Fie. Can Be Nullified and Even Converted Into 1, and the small lead balls made up of atoms it would seem to logically Repulsion, By Electric Currents Properly were slightl follow that the forces of gravity Applied. pulled over towards the large spheres. must de- In his first experiments pend in some way upon attractions which Prof. Nipher applied a high tension atoms exert upon each other, and current from a due to continuous operation and the experiments static machine to the fact that the atoms the large lead balls, see are separated, at have been repeated time and again, always Fig. 2. least in solids and liquids, No difference was noted whether by extremely with the sanie result. the positive or negative small distances, we might expect terminals were ap- these inter- Prof. Nipher's mechanical apparatus replied. In one atomic forces to be relatively of these experiments the more powerful sembled that used in the "Cavendish masses were "repelled" than are those of ordinary gravitation. (normal gravita- experiment," by which it was first experi- tional attraction had been nullified Until recently, however, the mystery link- mentally proved and that Newton's law of uni- changed to repulsion) by a force ing this interatomic activity with the force versal nearly gravitational attraction applied to twice as great as the initial gravitational of gravitation baffled all attempts at solu- small bodies in their action upon each other repulsion. This effect is shown at Fig. 2

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-47744crrrT"(rf(cr ,w CAW Vrr/artckwaL :LOVE Pii<7f MOnCRS U(D[abMICNr army mu I+YAtEh 20 RnFriit5 AC w45 fit 1.7.R+1..'r .44741o((N(.vKY(rtvJJ(3 S+O.v- C.41511, R[ rwf(M P1LrAIL BOATS !rE[.(O NVTN rn?NN MAE NW7ORVM.aL CiaAKf.tn'Sfr,,ct t .405313 /1CACL tYCirQG1 L!WO SptE(S t Ah L.Já c 1cß' wt wt.) cMP4(M CUQT f . r .,v PCOSIV NO rAr/OMaL I:/aAWK mace nit c.+nVC_ rt RTOVt.stOwr ws nOrS CA/Sir wrr<íuQCEtvrqMpCLe" 5.1%04779r wilRnqL 4T144CTrJ.. Several Simple Diagrams Which Show, In a Manner Understandable to All, the Essence of the Epoch -making Experiments on the Effect of Electricity on Gravitation, as Conducted by Prof. Nipher at Washington University, St. Louis, Mo.

tion, altho many scientists had tackled it. at short distances, just as well as it did to In further experiments Prof. Niphcr de- But at last experimental proof has been small terrestrial bodies under influence cided forthcoming the to check his results. To do this he thru the untiring labors of of the earth. This apparatus consists of a replaced large Professor the solid lead spheres with Francis E. Niphcr, of the St. delicate torsion suspension fiber (see Figs. two metal boxes, each filled Louis with loose Academy of Science. In a pamphlet 3 and 4) a light. rigid arm at the lower end cotton batting. These hollow issued boxes November 8th, 1917, Professor of the fiber suspension. and at either end (Continued on pogo 803)

www.americanradiohistory.com 744 ELECTRICAL EXPERIMENTER March, 1918 Electricity and War in the Films THRILLS, thrills and still more serration post by telephone. Another scene THE TELEPHONE MOUTHPIECE- thrills! seems to he the slogan be- shows the up -to -date radio equipment on HOW TO USE IT. hind the majority of motion pic- board the Zeppelin. Science and experience have combined tures on the screens in these tem- The mammoth Marconi wireless station to determine the shape and size and ma- pestuous times. Surprising it is located just outside Los Angeles, Cal., re- terial to be used in the proper construction indeed the extent to which producers will cently taken over by the U. S. Govern- of the most efficient mouthpiece. go to secure the "reel" hair raisers. and in ment, was made use of in filming some of This part of the telephone is designed to nearly every instance Science plays the all the important scenes. gather the sound waves of the voice, and important rôle. The third photo shown is taken from a will do so more efficiently when the lips of In the wonderful advance made by the later episode of the gripping film drama- the person speaking are about half an inch photoplay in the last few years, from, and directly in front of it. the small and intricate details It is designed exactly for the have come to receive more and purpose of most efficiency by ac- more attention. The critical commodating the sounds from public has learned much in re- close ptoximity and excluding cent years: therefore it would the distant sounds which would not do to make use of scientific interfere with the transmission. apparatus nowadays without Did you ever stop to consider some regard for its cor- how you hear only the speaker rect appearance and application. and not the other sounds of the Foremost amongst the new films room in which the speaker is? may be mentioned Thos. H. Incé s When speech is directed to the latest production "The Zeppe- mouthpiece at an angle, or from lin's Last Raid." Mr. Ince has a distance of from six inches to had a phenomenal rise in the a foot away, the person at the motion picture field and must be other end of the line cannot complimented on this splendid hear your voice distinctly.

Above-Two Teuton Plot- ters Operating a Spy Radio Set in the Woods in "A Daughter of Uncle Sam." Left -Preparing Zeppelin Bombs for A c t i o n by Means of Magnet In "The Zeppelin's Last Rald." Right- Another Scene on the "Zep," Showing the Radio Instruments and the Operator. and timely picture. A word would not be "A Daughter of Uncle Sam." showing the The best results will be obtained by speak- amiss regarding the work he has done to inner workings of the German spy system ing directly into. and close up to, the mouth- advance the motion picture along the path in this country. The action abounds in piece in a clear. not - too -loud tone of voice. of big things. Five years ago he was next many stirring scenes and the one illustrated to being down and out, but he had an idea shows two German plotters secretly operat- to ing a Radio station in the woods. WIRELESS FOR ST. PETER'S IN and struggled along till the chance came concealed ROME. produce on a big scale, his foremost and initial photoplay sensation being "Civiliza- The establishment of a wireless station on tion," which cost thousands of dollars and HUN RADIO AT NIGHT DARES the dome of St. Peter's in Rome has been employed hundreds of people to produce. U. S. TO STRIKE. suggested to the Vatican so that it may se- The Zeppelin's Last Raid" shows vividly Commanders and crews of the American cure independent transmission 'of foreign the danger that the United States is exposed destroyers operating in European %raters messages of diplomatic character in code to, and to save us if possible from the are talking about a grim piece of Hun hu- and also receive confidential and reliable re- lesson that was so bitterly learned by Bel- mor. Nearly every night the commander of ports from the vatican's representatives gium, France and England. one of the destroyers receives by wireless a abroad. The question of speed is involved The story is woven around Mr. Hick- message reading: since at present wire transmission from man, the commander of a Zeppelin, and "My position is (so many) degrees north France and England consumes 24 hours Miss Markey, a young and pretty girl who, and (so Marty) degrees west. Conte and while much longer is required to receive with hundreds of others, is secretly work- get me. I'm waiting for you." The mes- messages and news from the United States. ing in an effort to rouse the populace sage is always signed, "Hats Rose." It is pointed out that the wireless would against Kaiserism. The commander, like Rose is the German who took a submar- have the advantage of dealing with Switzer- many other officers in the army and navy, ine into Newport two years ago. Accord- land, Austria, Germany and Russia. The is also a member of the same organization. ing to the story past around by the men Vatican never has been able to rely upon The attack of the Zeppelin upon the de- engaged in the thrilling and hazardous task newspaper reports for quick news. fenseless British hamlets is one of the most of seeking submarines. the captain to whom The Italian Government is not likely to strikingly realistic scenes ever converted is directed the nightly messages of the Ger- raise decided objections because the vatican to the screen. The biggest thrill comes man sub -sea craft, sank two. The com- never has paid tolls on its messages. when the commander of the "Zep" dyna- manders of both were intimate friends of mites it, at the moment the crew attacks Rose. He has sworn vengeance. him for refusing to hurl bombs upon the It is disquieting for the American com- ELECTRIC LIGHT TO MARK defenseless city below. And the nerve - mander, but he has no fears. Twice, it is AERIAL ROUTES. stirring scene of the flaming dirigible rush- stated. lie has swiftly guided his craft to Electrical companies and town councils in ing downward to destruction is one not the location described by his enemy, but has the United States are offering to provide the easily forgotten. The "Zep" is complete found nothing. Still the mysterious wire- "lighthouses" necessary to mark the aerial in every detail and in one of the photos less dispatch comes every night, no matter routes hem cell Dayton, Ohio, and Indian- herewith may be seen the releasing of the where the destroyer may be. Others catch apolis. Ind.. and other cities to be used by powerful death -dealing bombs. The orders it, and thus the weird story is told where - the aviation corps of the United States are given to the men from the main oh- ever the hornets of the sea are seen. Army in training students for this service.

www.americanradiohistory.com "ELECTRIC WINTER-TIME COMFORTS"

T h Electric Lop" Will Keep You Warm. Be. Ida* Giving a Cheerful Fireside Crand.dad'eGlow, lust Like Oven Firo.place.

For Warming Bedrooms and Other Small Apartmente, the Flat Sheet Heater Stave Here Shown Proves Extremely Handy and Efficient. BUM In 600 to 4.000 Watt Sloes

Below.-The Electric Bathroom Healer Sheds a Radiant Glow-So R ttttt hIng and ol lust the Proper Size for the Purpose.

A Portable Elec. Olo Range Is the Latest Luxury for Milady. Can be Used on Dining Table.

While -Pop" Lights His Cigar from an Electric Lighter, Sonny "pope" the Corn in His Electric Corn Popper.

Brr.Rrr! ' Ti, a Cold Night lit the Yukon But the Lady Should Worry. for She Is Rolled in an Electric Blanket Which Automatically Keeps a Certain Temperature.

Oh' Clarice' We Oldn't Know You Hed New Electric Heater for Use on Auto Engine.. It Plugs Into Something New In Hot Water Oevicee-the the Engine a Sure a Faceache-But Rest Assured. This Heats the Water in Any Lamp Socket and Makes Starling Warns Ina Pad Will Alleviate .Electrlo Spigot." Thing In the Winter. Electric to Any Weter Pipe. Your Suffering In a Short Time. Con. stantly end Attaches netts With Any Lamp Socket.

:4.2*avr,Mr,A

745

www.americanradiohistory.com 746 ELECTRICAL EXPERIMENTER March. 1918 How U -Boats Send Radio 1,000 Miles By lI. WINFIELD SECOR

THE Germans have developed sub- in the balloon antenna and the balloons are would be to connect up the high capacity marine radio- communication to a taken inside, hatches closed, and the craft dynamo to these engines, and this in turn fine art -they had to. This is so for submerged -all in almost less time than it to the special high power radio transmitter. obvious reasons -chief among which takes to tell about it. It is difficult for an Such a set, including the dynamo, would is that the success of the U -boat enemy ship to see the balloons as they are not occupy such a large space as might be campaign depends to a large extent on cleverly camouflaged, being painted partly imagined off -hand. Also the newer U -boats keeping in wireless communication with white and partly blue, so that against the are veritable submarine- cruisers, several the individual sub -sea boats and the pos- sky they are practically invisible. The hundred feet in length, which, of course, sibility of certain of their number trans- antenna wire is, of course. quite fine and gives a much greater space for the radio mitting intelligence to the nearest land base. invisible at even a short distance away. equipment. At first the submarines made use of fold- It has been a mooted question for some Many ingenious folding and other types ing or telescopic masts which did not ele- time as to just how far such a radio -equipt of masts have been perfected for medium vate the radio antenna very far above the sub -sea fighter could send a message. The and short range radio work on the sub- jerk- not more than 20 to 30 feet in most receiving ranee with such a balloon sus- marine. Several of these masts are illus-

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Sectional View of Modern Submarine Showing the New Telescopic Collapsible Masts Supporting the Radio Antenna, as Well as Motor Actuated Cable Windlass for Rapidly Reeling in Balloon Aerial Wire. The U -boats Are Said to Be Using the Balloon Aerial for Communi- cating by Radio Over Distances of Several Thousand Miles. cases. For ordinary intercommunication pended aerial is easily several thousand trated in the drawing herewith. An inter- between submarines this collapsible an- miles. using modern amplifiers and other esting practical telescopic mast was patented tenna served its purpose admirably. Where refinements in the radio art. The writer by a Yankee inventor several years ago long ranges were to be negotiated. either asked several well- known radio experts (U. S. patent \o. 1,099,361) and is shown in in receiving or transmitting. however, it their opinion on the possible sending and detail at Figs. 1 and 2. The inventor, Mr. became a real problem. receiving activity of a balloon -aerial equipt Joseph Raes, covered several modifications One of the latest Teutonic improvements U -boat and they practically all agreed with of the basic idea in his patent. In one type in this arm of the naval service is the the ideas exprest by Mr. F. H. Kroger, a continuous flexible metal cable is used, utilization of balloons for elevating the chief engineer of one of the leading Ameri- Figs. C and D. By following the path of the U- boats' antenna wire to a height of 1,000 can radio companies, that ; with fair cable in the drawing it is seen hots, when a feet and more. In this way vast distances weather conditions, and with the proper pull, as produced by a motor, is applied to can be covered and valuable intelligence radio transmitting apparatus tuned to a the lower end of the cable, it causes all of sent by radio to a second relay submarine high wave length, it would be possible for the sliding telescopic members to be ele- if necessary. so that it is not improbable the submarine to send a wireless message vated. The upper end of the cable is se- that the news of ships' sailings from Ameri- 2,000 miles, and possibly 3,000 to 4,000 miles cured to the bottom of the top telescopic can ports could have been radioed to Ger- under extremely favorable conditions. The member. \ \'hen pressure is removed on the many by the aid of three or four U- boats. transmitting set used might, of course. be cable the mast descends by gravity. Our iront cover illustration as well as a special one rated at 15 to 25 kilowatts. A similar type telescopic mast is shown the ones herewith, show clearly just how If the sub -sea boat wanted to transmit an at Fig. B, only in this case the individual the balloons, two in number and fastened important message, she would in all likeli- sections are raised and lowered by a clever to a rigid equilibrium member. carry up the hood choose the night -time. She could then arrangement of gears and shafts. This antenna wire to a height of several thou- emerge and fly her balloon aerial with rea- elevating scheme would be considerably sand feet if necessary. The antenna, at its sonable safety. And for a long range mes- slower than the previous cable -operated type. base. is wound on a special electric -motor saj a requiring as much energy as men- The author suggests herewith a pneu- driven drum. This drum is instantly con- tioned above. it should be remembered that matic telescopic radio mast of the type illus- trolled by the throw of a switch, so that if there is atailable all the engine power re- trated at Fig. A. This is similar in principle a shin Conies into view. it can rapidly reel quired. All that ki otilll have to be done to the pneumatic (comprest air) lifting

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 747 cranes used in manufacturing planes, A WAR -TIME SUGGESTION TO tho, we amateurs have built up our present foundries, etc. With the proper pressure RADIO AMATEURS. organization upon our own lines. As our of comprest air, it is only necessary to close By Ilownao S. PYLE, problems were presented we worked and the suction blower pipe valve, open the high Electrician- Radio, U. S. N. finally overcame thetas. They were our pressure air valve attached to the pipe line problems -we fought them as such. Mean- from comprest air tank or flasks, and the FELLOWS, in writing this, I want to while the commercial companies met their mast rises up by expansion of the air within address it to the Amateurs -the real. barriers also and overcame them. Now it. When it is desired to lower the mast dyed -in- the -wool "hams," who have doesn't it seem reasonable that the com- quickly, the comprest air valve is closed and started in the right way a spark coil of mercial companies, having to build their the suction blower line valve slowly opened ; uncertain antecedent, a few discarded dry organization to the highest stage of devel- the air is thus re- opment, as theirs is moved and the mast a cold, commercial collapsed. Ordinar- proposition, many ily, no suction people b e i n g de- would be required pendent for t h e i r to lower the mast; living upon the suc- merely a valve cess of wireless as a opening to the at- commercial e n t e r- mosphere then prise - doesn't it which the comprest seem reasonable to air could rash to you fellow's to the outer air. grant that these An ingenious col- companies have a lapsible radio mast higher. more effi- was invented in cient service than Germany some the amateurs? Of years ago and sev- course they have, as eral of them have they must have to been used in this remain in business. country. It was Supposing a com- perhaps the lightest mercial telegraph ever designed thus company accepted a far - possibly too message from Port- light for submarine land, Oregon, to requirements - but Los Angeles, Calif., it possest the ele- would they deliver ment of speed. It it at its destination, employed four flex- a week or so after ible strips of .metal the filing? \Vould rolled on drums at a company send a the base. These message from Seat- strips were notched tle to Portland, on both edges and Oregon, and effect when the handle the transmission in was turned, the a few minutes but four notched strips hang the message of thin steel inter- tip at its destination meshed with each l,Ye CD/I,'rr:S/ air SP rY.O,t1 z /JrJ ,t and deliver it four o t lt e r, making a days later ? How lock - cornered Some Examples of Collapsible Radio Masts Adaptable For Use on Submarines. The Types long would they re- square tubular mast Shown Include the Comprest Air, Steel Cable and Gear Actuated Telescopic Forms. A Motor Operates the Gear and Cable Types Directly, main in business if about 8 inches they did? Yet these square. It was are both a c t u a l found possible to raise a platform contain cells from the family Ford, a lump of amateur examples of occurences on this ing two men on it to a height of 80 feet for silicon -you know the type. Fellows that coast in one week! In the former case: observation purposes when necessary. Two started with gigantic problems to face, no no excuse as a line of communication is men could raise the mast in a short time bt one to help and who have "stuck to it." available (or was at that time) between turning a geared crank handle. We have today, altho at present closed those two points at all times, with numer- by our Government, sticlt an efficient chain ous The accompanying illustration of a mod- relays if necessary. In the latter case: ern submarine shows how the various com- of amateur stations in this great country also inexcusable as direct 'phone connec- partments are arranged. It was prepared of ours, that. were it forecasted ten years tion between the receiving operator anti ago, would have brought derision down addressee was had. latter from official plans of such a craft. The the to be The upon one be so as to sug- location of the collapsible radio masts is who would bold finally heard of the message in a round- gest it. And if you will look up the "star" about way and after some trouble and in- given, as well as the position of the motor - stations, you find that they are driven winch for hauling in the antenna will prac- convenience, finally got it. tically all in the hands of fellows that ten balloons. An interesting feature not gen- I'm in the now, -yes, even five years ago -were strug- Altho commercial game erally known is that submarines are now a heart want gling thru many failures, working out their yet I'm "ham" at always, and fitted with submarine telegraph apparatus see them make a name. I keep in own problems, a to which operates by means sound waves 'nary beacon to guide them of in way. where they stand close tonds with the fellows, altho I'm sent thru the seater front powerful electric the right Look today foremost among the country's "all over the ocean" at times, so to speak. vibrators mounted on the hull of the sub- - It's only since breaking into the commer- marine. Sensitive microphones suitably youthful scientists and possest of an enviable knowledge of that most fascinating cial game that I saw the faults of our or- mounted on either side of the hull enable of mysteries- WIRELESS! ganization and I would suggest that our the commander to tell when a ship is ap- I have watched and grown up with them best "hams" spend a little time in com- proaching. even at a considerable distance, for the past eight years myself so am mercial service -even only a few trips on by the sound of her propellers which is some vessel. Operators are scarce and jobs transmitted thru the water. basing this on facts. While my stations never hung up any extraordinary records plentiful and I'll warrant you'll }lase your Then there is the latest safety feature- - for transmission, due to several handicaps eyes opened and it will result in better the telephone buoy. If the submarine should from outside sources which it was impos- service in the future among our own sta- sink and become unmanageable, the crew sible for me to overcome. yet niy interest tions. Think it over, fellows. If von can pull a lever which releases the tele- has been just as keen then all the years don't feel like joining the U. S. Navy. why phone buoy, which rises to the surface of and I hailed each new record with as much not try the U. S. Naval Reserve Force. the water. Any craft passing in the vi- delight as if it were my own. I did have They are looking for good radio operators cinity of the sunken sub -sea boat can open sensitive receiving apparatus, however. esery day. Come on. fellow "Radio- hugs" this buoy and, by means of the telephone which I kept strictly up -to -date and have put on your hat and take a walk to the inside it, speak to the imprisoned crew. spent many, many pleasant evenings (and nearest recruiting office-and don't forget Submarines send out sound signals of dis- wee hours) with the 'cans" on and am the great chances looming up now for a tress thru the water also, which may be proud to consider myself one of the "self - berth as radio officer on the vast merchant intercepted by another submarine or by a mades." marine fleet Uncle Sans is building- I.00k warship or steamer. ' To come to the subject of this article. into this -it will pay you.

www.americanradiohistory.com 748 ELECTRICAL EXPERIMENTER March. 1918 Electric Steam Boiler Most Efficient JUST one year ago, in the March, 1917, for a short time. They may, in fact, be injector, a steam valve. a water gage, a issue of this journal, we had the considered as serviceable appliances for pressure gage, a receiver for soda solution, pleasure of describing and illustrating turning to account any superfluous hydro- a water -level regulator, which automatically a remarkable piece of engineering electric power available, and as such they governs the working of the apparatus, a work carried out successfully by Ital- were utilized in numerous installations in safety and drain valve, a handle for work- ian engineers, viz., the application of vol- Italy before the war, when the price of coal ing this valve by hand and a feed -water canic heat to a steam boiler and thence did not exceed $8.00 per ton. At the pres- valve. to a dynamo, from which several thousand ent time they arc also found to he practical The high -tension type has the same com- horsepower were distributed at high poten- and economical, even in cases where hydro- ponent parts as the low -tension type, and tial to a considerable area differs from the latter only in northern Italy. Now, in the shape of the clec- we are confronted by an- trodes and the dimensions other ingenious and suc- of the steam dome, which cessful steam - electric STEAM PASSES INTO in the high -tension type stunt, due to an Italian en- THESE HOLES IN PIPE has the same diameter as gineer- Colonel Revel of the steam space. the Italian army, whose One of these high ten- extremely simple electric - \ELECTRIC FEED WIRE NP .2 sion installations in actual steam generator is de- EL ECTR /C FEED WIREN9 use in Italy consists of scribed in Engineering of STEAM eight apparatus, taking AARE London. As we do not .5 TEAM PRESSURE GAGE three -phase current at know just yet how to pro- 6,000 volts, each apparatus duce electricity d i r e c t being capable of generat- from coal or other com- OPPOS /TELY CHARGED ing 900 kg. to 1,000 kg. of bustive or explosive fuel, STEEL ELECTRODES steam per hour. we shall not find, possibly. In the Revel generator a very extensive field for ELECTRODE N '3 the transformation of elec- Colonel Revel's new elec- into heat LACE:/VC= trical energy tric -Steam boiler, as it uses takes place in the body of electric current to convert WATER GAGE STEAM CHAMBER the water contained in the water into steam. But steam and electrode cham- where there is superfluous STEAM VAG VE ber, the water acting as an hydro -electric power avail- BAFFLE ohmic resistance inserted W.TERLEVES able, there we should find / the electrodes ; the between the Revel electric boiler of production of steam there- great economic value. OUTGOING fore varies with the im- Especially when it is con- STEAM mersed surface of the elec- sidered that steam is pro- trodes, and assumes all duced by the passage of the values between zero and electric current thru water the correspond- SODASOLUT/ON maximum, at the almost unbelievable INLET NOZZLE ing with the various levels efficiency of 98 per cent. of the water in the steam That is, 98 per cent of the chamber. energy in the electric cur- COLD S VATER CHAMBER FEED WATER INJECTOR For starting the gener- rent sent thru the water is ator the circuit- breaker is actually converted into AUTOMATIC iVATER FED WATER VALVE LEVEL REGULATOR closed, the feed -water steam. The efficiency of /NCOM /NG FEED WATER valve is opened, and a the average coal -fired boil- small quantity of soda er is only about 50 to 60 solution is introduced per cent. from the small receiver to The principal character- give a suitable conductiv- istic feature of the gen- ity to the water. When erator is that for the trans- the water has reached the formation of e l e c t r i c S/PR/NG height of the lower edge energy into heat, and of the electrode segments thereafter into steam, use the current flows thru the is made of the ohmic re- water and commences to sistance of the water which TO HAND CONTROL LEVER raise steam, the steam has to be evaporated. The production increasing as Revel apparatus can be in- SAFETY AND DRAIN VALVE the water -level rises, until serted in any alternating - it reaches the working current circuit of from 200 pressure required. At this volts to 3,600 volts, and This Illustrates Graphically Just How the Revel "Electric Boller" Generates moment t h e automatic these arc the form of cur- Steam by the Passage of an Electric Current Thru the Water Between the regulator enters into ac- rent and pressures which Circular Metal Plates. The Resistance of the Water to the Passage of the tion, and the water- level. are usually supplied for Current Causes Steam to Form. and hence the steam pro- industrial purposes. In the duction, remain constant. Revel system, moreover, the production of electrical power has to be paid for at the In order to stop the apparatus the feed - steam is regulated automatically and con- rates now ruling. The Revel electric boiler water valve is closed, the steam valve is tinuously as required ; the apparatus is has been in successful use now for some closed slowly, and the bottom drain valve entirely automatic in its action and demands time in many Italian works. is opened by acting upon the hand lever no attention. Lack of feed water would The semi -sectional view of the new Revel until the ammeter has returned to zero. only result in a decrease or a stoppage in the electric -steam generator here shown will When the feed water leaves a calcareous production of steam until the feed water aid in understanding just how this simple deposit it is advisable, every five or six difficulty was overcome. A 97 per cent to 98 yet wonderful device operates. The work- hours, to free the boiler of the sediment de- per cent efficiency is claimed for this type of ing drawing shows one of these apparatus posited at the bottom of the truncated cone. machine, since the whole of the heat gener- taking current at a pressure of 500 volts, in This is obtained, without interrupting the ated by the electric energy is absorbed by the which we find the following arrangement: working of the machine, by increasing the water, the only loss being that caused by At the center, as shown, there is an elec- svater feed and by acting at the same time radiation from the body of the apparatus. trode and steam space; at the bottom a on the drain valve handle, the excess water The Revel generators are constructed to cold water space. Thru the steam dome washing away the sediment ; this operation, work at any pressure up to 14 atmospheres, cover run three brass rods electrically in- by a suitable action upon the feed water and can be connected up at any time with sulated from the cover. In the steam and and drain valve and by following closely the steam pipes from the ordinary steam electrode chamber there are three sets of the ammeter and maintaining the current boilers; owing to the rapidity of their ac- circular steel electrodes separated a short intensity constant, is carried out without tion they take up any excess of hydro- distance and rigidly fixt to the rods shown. changing the water -level and without im- electric (i.e., water -power electric en- Next we find a vertical steam pipe and pairing the working of the apparatus. The ergy) energy which may be available even steam pipe support and baffle; a feed -water apparatus may find adoption in this country.

www.americanradiohistory.com March. 1918 ELECTRICAL EXPERIMENTER 749 Eliminating the Smoke Nuisance by Electricity By WILLIAM 11. EA.S'l'ON Westinghouse Electric & \lfg. Co.

S every reader of THE ELECTRICAL Ex- properly adjusted, an almost complete re- system from static surges. Powerful PERI\tENTER knows, if a rubber comb covery of the suspended solid or liquid choke cOilS are mounted in the transform is rubbed against a woolen cloth, it matter, can be secured. It is, however. ers for this purpose Each transformer has becomes electrified and is able to attract impossible to remove gaseous particles in a number of different. high voltage taps so particles of paper, threads, and other small this manner. that the voltage of the direct current can objects. This peculiar phenomenon was It is. of course, impracticable to gen- he adjusted to suit the conditions at the known to man long before the dawn of erate directly the necessary high voltage installation. direct current. Alternating current is, All switching and control arrangements therefore. stept up to the desired voltage are placed in the low voltage side of the by means of special transformers a n d this high voltage .alternating current then changed into direct current of equal voltage by means of a rectifier, which is simply a large revolving commutator. T h e alternating current can be taken- from( the regular power line, but it is generally best practise to have the entire Cottrell system independent. Sepa- rate generator s, driven by motors operated from the main power line, are therefore usually employed. The system is also usually divided into a number of independent units, each with its Close -up View of 100,000 -Volt Mechanical Rectifier, Direct -connected to Synchronous Driving Motor. Note the Sparks at the \\ own generator, Edge of the Revolving Disc. transformer, recti- New Electric Smoke -eliminator Outfit, Show- fier, and set of pipes, -connected to ing Motor -generator Direct so that one or more units can be shut down system, the path of the high voltage cur Rectifier. 100,000 -Volt Transformer In the to the Background. ,ithout interferring with the operation of rent from transformer and rectifier the plant. It is essential that the rectifier precipitation pipes being kept as direct and history, for electricity gets its name from revolve in synchronism with its alternating - simple as possible. the Greek word "electron." meaning am- current generator and so it is usually The power actually needed for precipi ber, which, of course, acts just like rubber. mounted on the shaft of its generator; but tating the dust is insignificant in amount, It is our nature to endeavor to put into sometimes synchronous motors are used for and by far the greater part generated is practical use everything we know, and it operating the rectifiers. absorbed as losses in the system. Hence is therefore very remarkable that for at Great care must be taken to guard the the cost of operating the process is small. least 3.000 years no commercial applica- Much has been said recently about the tion, outside of a number of interesting recovery of potash from cement dust. This is obtained by means laboratory experiments, was made of elec- roacro r /ea' valuable by-product trostatic attroction. i of the Cottrell process. Today, however. this principle is being extensively used to solve one of our most IRON CRUCIBLES INSTEAD OF perplexing industrial problems -the sup- pression of smoke and dust. The smoke PLATINUM. from chimneys, the dust from cement Platinum is more expensive not. than at mills, blast furnaces, etc.. and the acid any time in its history and yet it is regarded fumes from chemical plants are not only as an indispensible medium as a crucible for intolerable nuisances, but also the visible use in analyzing certain compounds. It is. evidences of a great waste of valuable ma- however, possible to dispense with it in terial. \lany attempts have been made to ferro-silicon, an important alloy check these emissions but the Cottrell elec- used. in making steel. According to Dr trostatic process, (so- called after its in- Herwig, in a German technical paper, iron ventor) appears to be the most successful. crucibles can be used for this purpose if. in this process the gases containing the instead of the usual carbonate of soda and solid particles of soot or dust, or the liquid potash method, sodium dioxide is used in the particles of acid, are past thru vertical ignition mixture. Great care must be taken tubes or pipes in the centers of which fine to reduce the ferro- silicon to as fine a pow wires or chains are suspended. The cen- der as possible, to remove all coarse parti tral conductors are connected with a source vies, and to mix the powdered silicon thoroly of direct current of from 40,000 to 100,000 and very uniformly with the dioxide, as colts potential and the pipes are grounded. otherwise dangerous ebullitions might take The floating particles in the gases passing place, which would nearly empty the crucible thru the tubes become electrified and arc and cause spattering. attracted to the walls of the tubes to which they adhere. At intervals the current is NEW WIRELESS STATION turned off, the tubes jarred or hammered OPENED. by a motor- driven device, and the accu- mulated dust falls into suitable hop- Pre- The newspapers of Willemstad, Curacao, then Section Thru One of the Electric Smoke wireless pers below. \ \'hen all conditions, such as cipitation Units. Several of These Are Used S. A., recently began publishing Boiler. The the length and diameter of the tubes, the in the Chimney -path from the dispatches received by the new wireless sta- Soot Particles Are Electrified and Deposited tion there. Dispatches are received from speed. temperature, and consistency of the Upon the Walls of the Chamber, the Latter gases, and the voltage of the current, are Being Cleaned Out Periodically. several European and American stations.

www.americanradiohistory.com 750 ELECTRICAL EXPERIMENTER March, 1918 THE FIRST TROLLEY By GEORGE HOLMES

AGREAT deal of historic interest is up a little -ways, then pop went the motor. and [veld the particles of brass to the com- attached to the modern trolley Mr. Sprague, who realized the car wouldn't mutator segments, short- circuiting them - car. Its evolution has been grad-aal make the hill, told the commission that some fire works!! It used to cost some and the present car is the result of some "testing" had to be done and sent one nine to ten dollars a day to buy brushes for many years of trials, experiment, of his men to "bring the instruments." The a half dozen cars. Later on the present and failures, not to mention the many amus- crowd waited and waited as the hours past style carbon brushes were brought into use. ing incidents that went hand in hand with and finally left for their homes. Mr- Sprague stuck to his job, however, and the early pioneers. Mr. Sprague laid down upon the seats among several hundred other inventions he is responsible for the multiple -unit control Jt system now in use, whereby a train com- any number cars can be GM' CABLES prising of motor A:rD started and stopt from any individual car CLAMP in the train. TRGLLEY' In marked contrast to the first coinmer- CARR/AGE cial trolley of uncertain progress, we show CONTACT---Th herewith the very latest "one -man" automa- YfEELS tic trolley. The problem of providing better ; .vro - TROLLEY- and more frequent service as demanded by _4 r:IRE growing communities, and at the same time reducing operating costs to meet the competition created by the so- called "jitney" TW /N L EARS automobile field has TO CAR in the electric railway led to the evolution of various forms of L light weight "Safety" or One -Man Cars. This type of car is now in operation in r. many parts of the country and enables substantial economies in the direction of reduced power consumption per passenger 11, tlPTT,r-iiI -0-A-0,0Wrh41 i41,0 l If.' haul. reduced car and track maintenance and reduced platform and operating expense, not to mention a relatively low first cost. For branch lines and territory having an intermittent traffic. this type of car appears to be especially well adapted. While safety is fundamental in any operation of railway cars or trains, this factor is. of course, particularly important in the operation of the new one -man Safety Car. \\here a single operator is entirely responsible for the control of the car and the sole dependence in the event of danger, such sees, They're Old- timers- Heroes of the Initial Run of the "First Electric Street Car." service demands that every automatic safety The Now Familiar Trolley Pole Was Unknown Then. Instead, a Small Four -Wheeled feature possible be provided in the system Trolley Bogie Was Hauled Along, the Current Flowing In Thru One Set of Wheels and Out Thru the Other Two, Two Trolley Wires Being Necessary. by which the car is controlled. In addition. practical economy and convenience argue

The first attempts in electrifying street and went to sleep ; about ten o'clock his strongly- for the performance of all possible cars met with great opposition from the assistant arrived bringing the instruments - functions automatically. then existing horse and cable car companies, hco mules!! The safety control devices are air oper- and even the public was slow to grasp its Before the final car was made the engin- ated and act in such a manner that the full import. The few concerns which eers were pretty much on the go-every motorman must be at his post and attentive sprang up at that time used many and varied car was tested after a run (every half - to his duties before the car can proceed and ways to induce the transportation companies hour) the road being about ten miles long. must remain alive and alert in order to keep to adopt the new means of propulsion. The brushes had to be replaced after each the car moving. Should the motorman be It is amazing to note that the engineers trip, as they were made of brass and oc- incapacitated by sudden death or should he in those days took on contracts for in- casionally the entire car was out of running remove his hand for any reason from the stallations that even now would be con- order. Sometimes the brushes would arc (Continued on page 805) sidered "big chances." With hardly any factories for making such parts as were semi -standard, (for most of the installations varied pretty near as much as the weather) and the difficulty of securing funds and materials, they agreed to have cars running in such short periods of times as two or three months. Tracks, pole lines. power houses, cars and all the other para- phernalia! The Bentley -Knight Co., had its shop on Tenth Avenue. New York City. where most of the equipment was made and many patents were granted them, among other, being that on the underground "shoe" contact system. Frank Julian Sprague's early efforts also tend to show what difficulties were experienced by his company. During a storm the overhead wires became covered with ice and the motorman had to get on top of the car and hack off the ice with an old broom. The first trolley cars installed in Rich- mond, Va.. were rather unique, seating but a few passengers. The trial trip was to take place in the early evening with Mr. Sprague and his as- sistants; also most of the town was out to sight. The car ran see the grand fairly In Marked Contrast to the Early Trolley Car Shown Above, Is this "One -man Automatic well until it struck the up -hill grade. On Trolley." It Is Built Like a Machine Gun. The Motorman Controls the Power, Brakes. it's seven odd horse -power motor it labored Track Sander, Door Openers, Collapsible Steps, Bell and Lights.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 751 Electric Power from the Wind

TII E Fuel Administrator has had a given distance from the center of the w becl rital minds of the country have been con- hard time of it, trying to "educate" and that the power then is delivered to the sulted on this problem and in the weeks just the people in all parts of the coun- power shaft. instead of acting as a barrier try to burn less coal. Coal is expen- to the wind. This is one of the features sive today -and hard to get. Think which give greater efficiency to this type of how much easier would be the Fuel Di- wind power wheels. rector's problems if the land was dotted Another feature of this design of wind with thousands of electric wind -power powee wheel is the automatic controllability. plants of the type here illustrated. It is 13y means of a centrifugal two -hall goy not necessary that such plants be kept small error or by a resistance type electric governor, the vanes are varied in their angli. to the wind in case of high wind velocity so that the motion of the wheel is kept from running above a given speed. This protects both the power plant and machinery from unnecessary wear and strain. The automatic means for stopping tin- mill when the storage batteries are charged and throwing it in the wind when an given number of ampere -hours have been discharged, all simply means that when the plant is once properly installed you are assured of perpetual and abundant service. without further expense or attention except oil for the plant once a year, distilled or rain water for the batteries and reasonable attention to your generator. The small farm type plant here shown supplies electric power for a large group of buildings. it is automatic, starting and stopping according to the condition of the storage batteries.- It charges the batteries about once a week on the average. One of the photos shows the electric control switchboard, including the volt and ammeters. automatic charging cut -out.

THE THIRD LIBERTY LOAN AND YOUI This country had not been at war with Germany for many days before realizing the essential importance of the trained electrician in the Navy, in the trenches, behind Appearance of Automatic Electric Switch- the lines, at the various headquarters, and board Used in Wind -power Electric Plants. in Washington. To consider that city alone. American Windelectric Generating Plant of It Cuts in the Dynamo When the Wind -mill and none of the others where war prepara- New Design. It Charges a Storage Battery Has Attained the Proper Speed. About Once a Week. The Plant Shown Sup- tions are going on, the demand for electrical plies Electric Light and Power for a Large service is insistent. The War Department's of Buildings. like those seen here and there on farms Group system of communication with the thruout the country -they can be built in outside world must be of the best. Here there must have been many adjustments it large sizes so as to develop hundreds of past there horse -power -even thousands of horse- be no fraction of a second lost in the trans- the interest of speed and efficiency. mission of messages. The best of the tech in this war stands in tilt power. Such a large wind -power The electrician place of the ancient runner as s plant for town and municipal util- H ity is illustrated here and was de- transmitter of 'intellicence. o' such as the signed by E. H. Manning of may hear a message first Marathon racer brought o: Tomah, Wisconsin. in- The small farm size plant illus- the victory at Thermopylae man who Hashed !b first trated possesses several unique deed. the VVWI\VV/',t.t//¡//; ,:11iVY-Wl%Wl word of the safe arrival of Persh- features which lend themselves ',rifled well to the driving of dynamos. ing', force in France per The working parts of the mill just such a service for the Ameri- are enclosed in weatherproof cas- can people as did the mrssenge: usho his The .-atior ings and these are filled with oil ¡are up life. lias been calling for the ,-t-vice, to insure perfect lubrication at all J !MI the techn times. The steel tower extending not only of electrical C of the mat: wht above the wheel securely anchors lsi. C ' cian. but also bottom iii dreams in terms of volts until hr the wheel at the top; the and life -sav- is carried on heavy duty ball bear- ..m. creates death- dealing ing devices for use in this conflict ings, thus making a construction 11:::.: , taken se which will stand the most severe N1 i Never has the inventor wind storm. Every bearing of ,11 11/ prominent a part in war. His idea, Npr snatched up with the service is a ball bearing, giving lou are being 111111011 in the hope greatest efficiency at all times. nmu î greatest eagerness that In operation the power vanes they may be applied to a weak spot sers on the Western front. to some are each rotated on their respec- __,. 11.. warfare. tive bearing in such a manner as condition of submarine to expose them to the wind at the or to the over -head warfare. angle of greatest efficiency at every it has been impossible for mast degree of the circle, while travel- men to follow the develi'pment of ing with, across, and against the Fz;k 11 the electrician in war times, fascinating as that subject may be. A wind, there being about 30 degrees Pr?t only of the circle when the vane _r.1. more de:inite idea was presented comes against the wind edgewise iá at the recent exposition in New to a degree where it is not efficient. F9 ©7 . York City. industrial lighting devices. for instance. llave been It thus becomes evident that all Small Town Windelectric Generating Plant Intended for Supplying ¡4, C <,i wind pressure is delivered at a Light and Power to a Whole Community. (-,'n tinned ('aqn

www.americanradiohistory.com 75? ELECTRICAL EXPERIMENTER March, 1918

HISTORIC LIGHTING PLANT AT Women Now Study Wireless APPLETON, WIS. A class in wireless telegraphy for women the Navy who went down with the Antilles The illustration shows all that is left or has been estahlisht at the East 86th Street According to the report of the officer in what is thought by many- to have been the branch the Y. M. Mrs. of C. A. by Herbert charge of the armed guard on the Antilles first commercial incandescent electric light Sumner Owen, the founder and director of the behavior of the Navy personnel thru- ing plant in the world. This picture was the Wireless Classes at Hunter College out was highly commendatory. The two taken recently by H. G. 1). Nutting of the Electrical !World, at Appleton, \ \'is. It shows the steel shells of the old vertical waterwheels now broken to pieces and lying on the ground. The wood construction is what is left of the harness and support, and on the other side of the little bridge are the needles holding the water back in the flume, which is till connected with the Fox River This plant has been mentioned by many writers and referred to by Samuel Insull in speeches and in reminiscences of early days. While it is held by some that it was the first incandescent lighting station in the world. recent researches of William E. Kelly of Chicago. who has given considerable thought and time to investigating historical events in the industry, seem to indicate that this was the third Edison electric lighting station in operation. According to the best data which Mr. Keily can obtain, the Holborn viaduct in London was started either on Jan. I2, 1882. or April 11, 1882, these two dates being fixt by separate authorities. The historic Pearl Street station in New York was started on Sept. 4, 1882. The record of the Western Edison Light Company of Chi- cago. which took the contract from the Appleton Edison Light Company for two K dynamos, to be operated from water power and to light 550 lamps, was dated Photo In Underwood and Underwood © Aug. 15. 1882. Edward T. Ames, still living An Interested Group of Young Women Studying the Mysteries of Wireless at a New York in St. Joseph, Mich., was sent by the West- School. So as to Be Ready to Do Their Part When the Call Comes. ern Edison Light Company of Chicago to install that machinery. He has stated that and the Marconi Radio School. The Y. forward gun crews. in charge of Lieut. the Appleton station was started on Oct. apparatus R. M. C. A. offered the use of their (Junior Grade) D. Tisdale, remained 15. 1882. This makes it the first Edison Mr. and the services of their instructor calmly at their gun stations while the ship electric lighting station to be driven by Bohn to Mrs. Owen, so that women could was sinking and made no move to leave water power and the first Edison station learn wireless telegraphy and thus aid their posts until ordered to save themselves. in the West. their country by teaching men and replac- An instance of remarkable coolness is cited ing them in many posts relieving them for in the case of one member of the gun crew active service in branches where they are who was rescued from the top of an am- [Editors .Cute: -Those interested n the more needed. The photo shows a class in munition box. When he saw a steamer history of the first steam- dri:en eleetrir radio engineering. coming near to pick him up he advised the central station in .America will find an au- Eighteen women have already past the ship by semaphore not to come too close as thentic article describing the Pearl Street U. S. Government tests, hold licenses. and the box he was sitting on contained live station in -Wet. York City in the January, are thorolv capable of becoming code in- ammunition. 1918, issue of this jonr,ral. 59S.] structors. should the Government decide to use them.

ANTILLES' RADIO OPERATOR DIED BRAVELY AT HIS POST. Secretary Daniels has sent a letter to Robert Ausburne. who is employed at the Union Club, Fifth Avenue and Fifty-first Street, New York, commending the action of his brother. C. L. Ausburne, radio electrician first class, who went down with the U. S. Army transport Antilles, when :t was sunk on October 17. Attention was called to the bravery of this radio operator in the findings of the court of inquiry, which stated that Ausburne went to his station to use the radio to give warning rather than attempt to save his own life. Ausburne and Radio Electrician Mac - Mahon were asleep in adjacent bunks, opposite the radio room, when the ship was struck. Ausburne, realizing the seri- ousness of the situation, told MacMahon to get his life preserver on. As he left to take his emergency station at the radio key he shouted to his companion, "Good- by, Mac." This was the last MacMahon saw of him. Going to the radio room. MacMahon found it locked, and, realizing that the ship was fast sinking, attempted to get Ausburne out, but without success. Ausl urnc originally enlisted in the Navy at New Orleans. February 25. 1908. After eight years' service he reenlisted on March A Remarkable Photograph Showing What Is Thought to Be the Remains of the First Hydro. 15 Year. 1 1916. He was one of the four men of Electric Plant In the World. It was Built in 1882. and Started on October of That

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 753

NOVEL ELECTRIC STRIP higher the temperature required to cause it SEAPLANE CRASHES INTO RADIO HEATERS. to bend still further and break the circuit. TOWER. For crane cabs, valve, inter and pump By the use of this device it is claimed that The extraordinary and remarkable photo houses, watch and signal towers, turn table 40 per cent of the energy now used in the here reproduced shows a British seaplane cabs, theatre ticket booths, exposed and excess heating of irons, percolators, caught in the steel girders of a wireless remote roosts -these are some of the loca- toasters, chafing dishes, etc., can be saved, tower over 300 feet high. The plane, while as the exact amount of heat required can emerging from a thick mist, hit the tower be obtained and the excess eliminated. and was caught firmly in the steel lattice work. The pilot, who was stunned, was 3,000,000 H. P. AVAILABLE AT flung from his seat and fell on one of the NIAGARA WOULD planes, where he lay unconscious over 300 SAVE COAL. feet from the ground. The seaplane's en- CA. WINDER, in a recent address gines were wedged into the interstices of Itere before the Schenectady Section the girders so that the body of the machine of the American Institute of Elec- stuck out at right angles. trical Engineers, urged the use of Niagara A small body of bluejackets were at work Falls power as one means of solving the painting the tower. One of them. a seaman coal shortage problem. \1r. Winder spoke of the Naval Reserve named Rath, climbed as follows: up the inside of the mast until he reached "While the Nero of smug indifference and the machine, and then crawled out onto the ignorance is fiddling away, the great coal plane to hold the pilot until help came. fields of the earth are being burned up. Two more men, Ordinary Seaman Knoul- While millions of horse -power are passing unused over vast water falls, great industries are languishing. Water power sites have virtually been roped off and 'Verboten' signs posted by our national legislators. New Electric Strip Heaters Which Are Well Adapted to Heating Small Booths and Clos- Now that the coal supply diminishes and ets. water power is throttled. what chance has the electrochemist, the greatest user of Lions in industrial plants and factories power, to expand to meet the increasing where the new strip type. steel jacketed, demands of the present day? The electro- electric heater units have found application. chemical industry is vital to the success of These units may be connectecd to either the great world war; that water power is D. C. or A. C. circuits -115, 230 or 250 vital to this industry will be shown in the volts. As electric lamps are placed where following paragraphs," he said in part. light is wanted so these units are distrib- "Tite electrochemical industry can be well uted where heat is required. The dimen- divided into three classes. sions are 3/16 x 1% x 23sÿ. Such heaters "First -Those that can't be moved from take up a minimum of roost and give the ílountry by any means and will stay re- enough heat to keep a small booth com- gardless of the cost of power. fortable. "Second -Those existing at present, and to a greater or less extent depending upon NEW AUTOMATIC CONTROLLER natural conditions for existence and growth. FOR HEATING DEVICES. "Third -Those having no footing in the A Western concern is manufacturing an country or not as yet in existence. automatic controller that regulates the "The first includes copper, zinc and rare amount of current delivered to any heating metal refining and electric steel production appliance and maintains the heat of the ap- and is perhaps, as a class, the largest user pliance at an even temperature. This de- of power. Class two included, in the order vice is made in two types, one for alternat- of their importance, the following: Alum - ing current and the other for alternating inum, ferro alloys, carbid, artificial abra- and direct current. The controller consists sives, alkali, chlorin, phosphorus, sodium, of a thermostat, composed of copper and cargon, disulfid, grafite and similar prod- iron riveted together, which is placed im- ucts. Class three would then include nitro- mediately over a heating coil and connected gen fixation and possibly products we know in series with the load. The heat from the little or nothing of at this time, there being coil causes the thermostat to break the cir- no power consumed within our boundaries cuit whenever the temperature rises above for products of this class. a certain point. The handle on the outside "Not a shell is made that is not shaped of the case can be set at any point lettered by electrically made abrasives. The electric from A to K, on the scale. A corresponds furnace from which the armor plate is with zero degrees, B with 10, and C with poured used electrodes made from coal by the aid of electric power, the re- sisting power of this same steel .. is given by electrically made ferro alloys. Merchant vessels are now using smoke buoys in which quantities of phosphorus A Remarkable Accident Which Occurred in and other electrochemical prod- England, a British Seaplane Being Caught in the Steel Girders of a 300 -Foot Radio Tower. ucts are burned, emitting large The Aviator Was Rescued. Miraculous as It May quantities of smoke, thus pro- Seem. tecting the boat from the submarine. High explosives utilize ton and Deckhand Abbott. past a rope out chlorin, aeroplanes, aluminum, to him, which Rath secured to the body and observation balloons proof the pilot and lowered him to safety. duced by the aid of silicon. In The gallantry of these melt is accentuated fact. every tool of the modern by the fact that the mast was badly dam- army is in some way dependent aged, and might have at any moment colon the electrochemical industry. lapsed. The damaged fuselage was only Furthermore, our military prep- held in a horizontal position by the engine arations are already calling for being jammed between the girders. and at An Automatic Electric Controller Operating on the Ther- very considerable quantities of the height of 300 feet the wind caused the mostatic Principle and Designed for Use with Heating many electrochemical products mast and the machine to sway severely. Appliances, Such as Plllowets, Blankets, Etc. for which ordinary demands are threatening to fall. The pilot owes his small or non- existent and which preservation to the intrepid gallantry of 160. The turning of the handle causes the were therefore not produced at all or pro- these three men, who, while alive to the contact point which touches the thermostat duced in extremely small quantities. The risks they ran. performed the rescue with- to move downward and bend the thermo- increased demand for our vast army will be out regard for personal safety. The Albert stat. Thus the more the thermostat is enormous. England, for instance. always medal will probably. be awarded them for bent the more heat is necessary and the (Continued on page 7921 their bravery.

www.americanradiohistory.com 754 ELECTRICAL EXPERIMENTER March, 1918

JUMBO GETS HIS HIDE toria. electricity can be utilized to promote ively coupled by a transformer with a VACUUMED. the falling of rain over dry regions. closed oscillating circuit, comprising a Jumbo, the elephant, likes to have his hide The specification states that the atmo- spark -gap and a condenser. which, in turn, cleaned the modern way. that is, with a sphere is known to comprise several dis- is coupled through a tuning coil. Deposi- vacuum cleaner. The iiluvtration shows a tinct regions. The section of the atmo- tion of the aqueous particles occurs upon husky pachyderm receiving his morning sphere concerned with the process subse- and in proximity to the conductor.

HEAVY DUTY ELECTRIC PHOTO - PRINTER. By V. 6. Ftll. This photographic printing machine is in use by a concern making large commercial photographs in big quantities. It has an automatic time switch making and breaking the circuit for six 500 watt tungsten lamps about once every minute, all day long. By means of a clock -work, it is set to give a print any desired length of exposure to the light. Each lamp can be turned on and off individually as well as adjusted' in different positions so as to regulate the intensity of the light on certain parts of the negatives to be printed. The switch has sliding contacts, mounted on a marble base which is inclosed in a sheet metal box. The wiring is arranged as shown in the photograph of the device. The automatic switch terminals are of brass, insulated by fiber over which a flexible copper bar moves with perfect contact and without appreciable friction. As the bar slides over to the opposition it lights a red pilot lamp, thus furnishing illumination in the machine while the photographic paper is being put in place over the negative. \ \'hen the switch bar is half way across the contacts the red lamp is connected in series with the white lamps, Photo fr in Society for Electrical Development © Am. Press Assoc. preventing the current from being entirely the Electricity Is Daily Finding More Ways of Lightening Our Labors -Here, Jumbo, the broken at any time during operation. Elephant. Receives a Thoro Morning Scrubbing -a la Vacuum. Before this machine was perfected great difficulties were experienced on account of bath la vacuum. The electric vacuum quently described is termed the troposphere. arcing switches and unreliable timing, but -a the users satis- cleaner is finding wide -spread application The earth's s urface is always negatively this construction has giten n many parts of the country for thoroly charged. and in fair or clear weather the factory service for several years. and expeditiously cleaning animals. Time troposphere is nearly always electrified vas when the only bath the elephant en- positively ; in wet weather, however, nega- joyed was that tvhtn he happened to get tive electrification of it is usual. The near a tank of water or a lake so he could troposphere contains transient masses of ill his trunk and spray himself. Now, the electrified particles which vary or alter the elephants belonging to such pretentious normal sign and potential gradient of zones shows as that at the New York Hippodrome of the troposphere. The invention is based receive a thoro cleaning every day. The on the diminution or cancellation by arti- animals look better and feel better -just ficial means of the potential gradient exist- the same as humans do. The elephants ing in fair or clear weather between the really seem to enjoy the novelty. elevated zones of the troposphere and the ;round. so that clouds are formed in the "HOOVERIZING" ELECTRIC affected troposphere zone and rainfall is CURRENT. procured. The invention utilizes an elec- A wide margin exists for the reduction trical conductor used to form a path for a of household consumption of electricity, in flow of energy be- furtherance of fuel and freight saving. For tween the earth and instance. despite the remarkable develop- such tropospheric ment of cheap. durable, metallic- filament in- zone or cloud, the candescent lamps the past few years. there conductor being con- has been no reduction whatever --in fact. nected to a good elec- an increase, rather -in the use of old - trical earth at the fashioned carbon -filament lamps, which the lower end, and at the modern lamps should have displaced. says upper end having a the weekly bulletin of the U. S. Food Ad- terminal of electrical- ministration. Carbon -filament lamps give ly conductive material ;css light than modern lamps and consume which will insure in- more electricity. The chief element in their trinsic electrical con- continued use is the fact that they are given nection with the cloud free to householders by many electric -light or tropospheric zolle. companies, whereas metallic- filament lamps A potential of the are sold. It would pay every consumer of order of 320,000 volts electricity many times over to purchase is maintained between modern lamps and economize by reductions the conductors, caus- in electric- current hills. Old- fashioned and ing coalescence of the ineffective types of lamps are also used for aqueous particles and street lighting and should be replaced with deposition upon the large economical incandescents of the latest earthed conductor. In types. a modification a single earthed conductor ELECTRICAL PRODUCTION OF is supplied with high RAIN. tension alternating - t, nrding to an Australian patent ap- current by means of With This New Electric Photograph Printer the Young Lady Can plied for by Mr. T. (i. Balsillie. of Vic- an alternator induct- Turn Out Ten Photo Prints Where One Was Produced Before.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 755

AN ELECTRIC SHELL FOR FIGHT- energization of the detonator the ING U- BOATS. explosive is exploded and, of It has remained for Mr. Lee A. Collins, course, will destroy the shell and of Louisville, Kentucky, to invent a new any objects within its radius such electric explosive shell for combating sub- as submarines, torpedoes or other marines. vessels. This shell is one which explodes after In lieu of a spark coil a more being fired from a gun or other projectors powerful battery may be used and or when dropt from airplanes and the like the ignition wires would be con- into the water. for warfare against sub- nected directly to the terminals marines, torpedoes and the like. The in- of the detonator. Under some ventor provides in this connection two elec- circumstances, it may be more de- tric conductors exposed to the outer sur- sirable to form the insulating me- face. of the such with insulating means dium of dry salt or like mineral. separating the electric conductors. This which will readily become a con- insulating means is soluble or made conductor of electricity upon coming ductive when in water. Another object of into contact with water and thus the invention cousists in providing a nor- close the battery circuit to the mally open circuit adapted to he closed spark coil. upon contact of the two exposed terminals with water or other conductive means, A NEW SECRET TELE- thus causing an explosion. By attaching PHONE TRANSMITTER. time fuses to the electric detonator it is in order to permit privacy in possible to cause an explosion to take place telephoning, a Chicago inventor at a predetermined time after the shell has developed a device shown in comes in contact with conductive means. the accompanying illustration instead of the instant that the shell strikes which can be used with any tele- conductive means. phone mouthpiece. By its use, it The invention also covers means for is said, that telephone conversa coating outer exposed conductors with a lions can be conducted in a very non -conductor covering, such as sealing - low tone and in a whisper, under paraffin or other suitable means Something Every Housewife Wants -a Positive Indl- wax, many conditions. It is pointed out cator That the Electric Iron Is "On" or "Off." The which can readily be removed when shell that the device is not permanently Tell -tale Lamp Solves the Problem. is to be fired, thus preventing accidental attached to the telephone and is contact, which would prematurely explode therefore not a fixture. the shell. The device is held on the mouth -piece of PILOT LAMP WARNS WHEN These exposed conductors must have all any telephone, and is held securely by ELECTRIC IRON IS ON. insulation covering removed at outer ex- means of the horse -shoe shaped wire held .\ new heater control just brought out posed surface when ready for use. Heavily by the two springs, which snaps over the is equipt with pilot lights which serve as a insulated covered conductors lead from the mouth -piece of the telephone. safety check on the woman who uses an secondary of spark coil and thru wall sep- To use the muffler most effectively, the electric iron or other extension device and arating the chambers to the respective on the workman %vita operates an electric terminals of a detonator, which may be of iron in a factory, clothing shop or similar any suitable type. One form being a bulb commercial establishment. containing fulminate of mercury and a They enable the operator to play safe and platinum wire within, connecting the elec- avoid waste of current. The pilot light tric terminals leading from the spark coil. acts as a silent watchman and signals danger The detonator is in contact with or rests %when the heating device is left in circuit against the explosive, which may be a unattended. charge of guncotton or other high ex- Take the case of an electric iron, for in- plosive, placed within the forward cham- stance, on an ordinary padded ironing ber. Obviously, therefore, as soon as the hoard: place it in circuit and leave it. platinum wire within the detonator is ener- with "heat on,'! for say fifteen minutes or gized from the spark coil, the explosive more. The probabilities are that quite an explodes, thus causing destruction to the impression will be made in the pad, and shell and all objects within reasonable Vy,J quite possibly on the board also; perhaps radius. A Newly Marketed Telephone Muf- the iron will even burn its way right thru a a "Secret" in operation, when shell is fired from fler. It Fits Onto Your Regular Telephone the board. . \nd then again, if the iron is gun or dropt from an airplane or other- and Is Removed In a Second. left to itself long enough with the current wise discharged into the water at an enemy on. the chances are that a serious fire may vessel, submarine or torpedo, one con- inventor states that the upper lip should result. These new Heater Control switches ductor and the outer portion of the shell, be prest gently against the mouth -piece, have been brought out particularly to min- which in this form is a conductor will speaking slowly and articulating distinctly imize fire hazard of this sort. come into contact or be submerge into evith the lips- almost a whisper (not down A wide variety of designs has been made the water when it strikes the point of aim in the throat). to suit practically any condition desired and closes the circuit of the battery thru If used correctly you will be plainly Each includes a pilot lamp and a 10- ampere heard at the other end, it is double -pole indicating switch. claimed, and no one near The flush types are mounted behind at- you (teed hear your conver- tractively finished face plates, and the sation, thus permitting pri- pilot lamp signals thru a ruby bull's -eye vacy and confining business They are ornamental in appearance and and personal affairs strictly are designed especially for use in the to yourself and those with home. whom you talk Surface types are for use in factories They provide for regular base lamps a, In Peoria, a hilly city in pilots but candelabra base lamps may be central Illinois, 300 automo- employed by using adapters. bilists operate automobiles without gasoline, that being USING EXHAUST STEAM. the number of electric pleas- More attention than ever before is being ure vehicles used in the city. paid this winter to careful use of exhaust steam in power plants. It may be applied One ton of safliires will be to innumerable purposes, such as heating Electric Shell For Fighting Submarines. When Dropt In the used during the year 1918 feed water for the steam boiler, for many Water It Becomes Active Due to Insulation Being Dissolved in At Point, Closing Detonator Circuit. one factory v.'here the washing put-poses, heating buildings, pas- jewelled bearings of electric teurizing and sterilizing. and the like. A meters are made. The small investment in additional boiler -room the primary of a spark coil. As a result, jewels are purchased in the rough and are equipment. such as an exhaust -steam heater, the primary of coil will induce a current put thru finishing and drilling processes will effect savings of several hundred dol- into the secondary of the spark coil and which require a degree of skill comparable lars a year in the coal bill of even a mod- energize the detonator thru wire. Upon only to that of an experienced watchmaker. erate sized power plant.

www.americanradiohistory.com March. 1918 756 ELECTRICAL EXPERIMENTER

summer a deep 'valley will be seen in the solenoid magnets, which close contacts for ANNUAL ELECTRIC LOAD RELIEF same time. An ordinary MAP RESEMBLES "ROCKIES." morning, between the "fall -off" of the the lamps at the night load and the beginning of the day 4.5 volt battery, such as used in pocket The familiar daily load diagram or overlap in flashlights. is sufficient to work this signal all electric load, while in winter the loads "graph" is plotted by practically filling up this valley. light and power companies. The accumu- the morning, Peaks. During the summer ALTERNATING -CURRENT GAL- months there are three distinct VANOMETER. peaks one occurring about - Herewith is illustrated the new North- 8:00 a. m. ; one about 5:00 The and third about 8:00 rup alternating -current galvanometer. p. m.; the maker points out that it is especially p. m. With the approachin following uses: (1) For fall and winter months, and a, adapted to the day. the accurate measurement of the resistivity the sun sets earlier each or of salt solutions and other the 8:00 p. m. peak moves back conductivity and electrolytes: (2) for the measurements of toward the 5:00 p. m. peak molten salt; (3) for the near the end of September the the resistivity of -t of the resistivities of molten two peaks overlap, giving measurement exceed- metals; (4) for the measurement of any combined peak greatly which small irregular emfs. ing any other peak, which rap- resistance in until exist; (5) for the comparison of small in- idly increases in height the bridge method and (61 the middle or latter part of ductances using December, when it becomes the greatest peak of the year. As the spring months approach the combined peak diminishes and finally near the end of March disintegrates. forming again the two separated peaks. While the above is a well known fact, the annual load relief map presents the changing condition in a most striking manner.

NEW AUTO TAIL LIGHT SIGNAL. .A novel automobile signaling device is provided in this new attachment for motor cars. It is claimed by the concern now offering this new- signal to the No -This Is Not a Picture of the Alps! It Is a Com- public to represent an added posite Load Relief Map, Showing the Rise and Fall of convenience and comfort to the Electric Power Consumed in Philadelphia, Day By Day, For One Year. motoring. It was perfected b' H. Hartman, a well- known lation of these curves soon becomes a mere New York inventor. record, usually filed away in some manner Usually the driver of his car has to ex- and always available for reference. and for tend his arm from the seat to warn other the study of load conditions. When con- cars in the rear. of what direction he is sidering the load thruout the year it is dif- going to turn or if he is going to stop. By ficult to obtain a comprehensive idea of the aid of this new electrical invention. all the whole since it is necessary to glance one has to do is to push a button on the separately at the greater portion of 365 steering wheel and the arm will indicate sheets. Such a record locks up a desired which way the driver intends turning. vision in confusion. When the car is going to stop. both arms The Annual Load Relief Map here illus- tly up. trated is a device for visualizing the entire Two buttons mounted on a small base load of the year and is -described by \Wm. are attached to the steering wheel -one for Le Roy Robertson in the A. I. E. E. pro- right and one for left: when both buttons 1917. Each daily ceedings for December. are pushed the stop signal is set Something Every Laboratory Requires 1 load diagram is marked off on card board his signal a Good -Alternating Current" Galvanom- are stacked up in To inform the operator that eter. This Is One of the Latest Types. and cut out. The cards O. a small lamp flashes up Reflecting Mirror. proper daily sequence. mounted and pro- is working K Fitted With vided with graduations for kilowatts. hours of the day and months of the year. for the comparison of capacities using the all properly arranged. The annual load re- bridge method. lief map here illustrated shows the Phila- The galvanometer is mounted on a base delphia load during the year 1916. of ebonite provided with leveling screws. Day Load. A distinctive feature brought The field magnets are laminated. Mag- out by the annual load relief map is the netizing coils are wound on non -metallic contour of the day load which is con- spools, which are placed on the field poles sistently uniform throughout the year. al- as close as possible to the moving coil. ways picking up between 7:00 to 8:00 a. m.. Pole- pieces are given a hollow cylindrical having a valley at noon and then falling off form about the moving coil. this special punctually at about 5:00 p. m. This stands shape preventing the coil. when on closed out clearly on the annual load relief map. circuit, from assuming a position of un and especially well, if one will imagine the stable equilibrium due to currents induced absence of the night load where it over- in its circuits by the alternating magnetic laps the day load at 5:00 p. m. The day field. The moving coil is long and narrow. load corresponds closely to the regular av- so that its moment of inertia is small. there- erage working day. by permitting high sensitivity with a quick Night Load The night load which picks is An Electric Semaphore and Tail Light For period. -l'he entire hanging system ex- tip rapidly at 8:00 p. m. in mid -summer, and Autos. Its Arms Point to the Direction posed to view through a glass front. The at about 4:30 p. m. to 5:00 p. in. in winter. Which the Auto Is About to Take. central housing is of non- conducting ma- corresponds closely to the lighting load. It terial to prevent the formation of eddy depends absolutely upon the hour of sunset currents. for its beginning and falls off rapidly, on the push button base and a red light shows on the attachment. An ingenious The sensitivity is adjustable thru a wide shortly after reaching its peak value. Af- strength of magnetism being it settles down to a low value arrangement flashes a beam of light on range, the ter midnight, variable by varying the current dirt the and drops off almost entirely when the either or both arms so that they may be street lighting goes off near sunrise. In seen at night. The arms are worked by field coils.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 757

A LUMINOUS BUTTON FOR PULL AN ELECTRIC CIGAR AND PIPE COMMERCIAL 110 VOLT MOTOR CHAIN SOCKETS AND LIGHTER FOR AUTOISTS. SIZE OF YOUR WATCH. SWITCH PLATES. Push the button and light your cigar or One of the largest electric motor manu- For attachment to the end of the pull pipe without a cuss word. ii your car is facturers has brought out a line of ex- chain of the pull -chain type socket and for fitted with this new electric lighter. It is tremely small motors in every size from matte for 6 volt storage battery only, and 1/200 to Y of a horsepower. Like a good not for regular electric lighting or power circuits. A This Cigar Lighter is very neat in appearance, takes up little room. will not "drain" the battery and w ill add greatly to the equipment of the finest and most luxurious of cars. The spiral coil element is so arranged as to allow its use with cigar, cigarette or pipe. The casing is finished in polished nickel and the handle is of wood with ebony finish. It is furnished complete with protector sleeve and five foot cord directly connected to lighter and either one or two point Edi -swan standard automobile attachment plug. Commercial Electric Motors No Larger Than By A t t a c h i n g a Watch Are Now Built Regularly. This Luminous Bead to Socket Chains and Switch Plates, it Be- watch, they run sure and true, doing the comes An Easy Mat- work to which they are assigned, year in ter to Locate Lamp Control Points In the and year out, with little or no attention Darkest Room. They The 1/200 horsepower electric motor here Glow In the Dark. shown in comparison with a watch shows how the electrical engineers have developed and perfected the motor so that a perfect machine, armature. field winding. bearings, and all results in a minimum of space. WAR INVENTIONS CLOSELY use with switch plates, a New York con- GUARDED. cern is now offering the trade a special Pursuant to recent legislation empower- radio bead and radio button which makes ing the Commissioner of Patents to with- it possible to quickly locate in the dark a hold the issuance of Letters Patent on light chain, push switch or gas jet. These the devices adopted by the Government for beads and buttons are made up of such a use in carrying on war, Commissioner New- size as to radiate ample light, it is claimed, ton has refused patents on over sixty -five to be plainly seen at distances from 10 to 15 inventions within the past few weeks. At feet. The bead is made up so that it can the present time a corps of \\'est Point and be easily attached to the pull chain by cut- Annapolis graduates trained in technical problems of war, carefully consider the ting off the large ball at the bottom of the Every Autolst Will Appreciate the Comfort chain and slipping the last ball into the en- of the Electric Cigar Lighter. hundreds of patents granted weekly for de- larged portion of the top of the bead and tails of military significance and choose then pinching the wires close together. those on which patent proceedings should Besides the uses mentioned, it is pointed A COMBINATION ELECTRIC CUR- be suspended during the war. The inven- out that these devices are of practical use LER, HAIR DRIER AND WAVER. tors thus deprived of patent rights may in lofts and cellars, where it is difficult to Ladies, both young and old, will find this offer their devices to the Government and locate obstacles and lamps under other con- new electric curler, hair drier and waver - sue after the war for compensation. ditions. all three in one - -a great convenience. It dries the hair quickly after a shampoo. NEW ARMY FLASHLIGHT FOR To use the curling iron it is simply neces- U. S. SOLDIERS. NEW INSULATOR CLAMP RE- sary to remove the comb. To use the This new army flashlight is designed PLACES TIE -WIRE. waver, remove the shield and comb. The especially to meet the needs of soldiers device is claimed to produce beautiful and sailors. It is small in size, light in The insulator clamp shown is designed to lasting waves or curls. weight and can be conveniently carried in prevent line trouble caused by the use of kit or coat -pocket. It is claimed to give copper tie -wires on telephone and other more light than many very large flash- lines. Besides preventing line trouble, it lights -plus special service impossible Saves time when constructing new lines and with ordinary types of flashlights. For in- also when repairing and rebuilding old lines, stance it can be buttoned on the coat. leav- as it can be detached and attached more ing both hands free; can be fastened on the tie- wires. This damp can be quickly than belt ; can be hung on any peg; can be car- used over and over again, whereas tie- An Electric Curler, Hair Drier and Waver For Milady. ried by its handle. as a lantern; can be stood upright on its brie.' a, a reading The heater and cord revolve together, so lamp; can be hung that the cord does not kink while in use above a mirror, as and the temperature is so regulated in the a shaving light heater that it cannot burn the hair. Renewal batteries can readily be pur- CLEANING WARSHIPS' HULLS chased in any BY ELECTRICITY. town in the United The old methods of cleaning ships' hulls. States and Europe. which was a laborious and lengthy process, It is especially is being replaced by electrical methods. adapted to the Formerly, it was customary to allow 170 wants of the to 200 man -days for the work. but recent- Ilome Guard and ly several electrically -driven machines have Boy Scouts. For been found to be both speedy and effective. policemen, watch- To Save Mlles and Mlles of "Tie -Wire," An Brushes and scrapers are used. and by their in e n, detective Inventor Suggests the Use of Thls New In- means, at a moderate expenditure of elec- reporters, sports sulator Clamp. tricity in driving the operating motors, an men and all other 18,000 -ton battleship can be, completely classes of men wires have only "junk" value when once cleaned in twelve hours, and vessels dry - who need to have used. docked after having been cleaned by this both hands free. The cost of manufacturing is but little method have been found to have remained this lamp should higher than that of the copper tie -wire. quite free from any subsequent marine prove extremely Latest Army Flash. Contributed by A. J. VIKEN. growth. useful. light for Soldiers.

www.americanradiohistory.com 758 ELECTRICAL EXPERIMENTER March, 1918 At War With The Invisible By R. and G. WINTHROP

TO you of the present generation, se- rewards fiendishness and malevolent ambi- minds of the allied planets. The president cure and prosperous in these happy tion. of the visiting commission, the Honorable days of universal brotherhood and It was in the year 2011 that Mars thrust Peros Venasarol, had hardly begun the peace, the world -destroying \Var of this new engine of frightfulness into the opening of his address, when the vibrator the Planets, that engulfed every strife. The terrific struggle was ending its on my pocket phone signalled. At the mo- shred of our vast planetarian system at the third bitter year and the contest between ment, the president's daughter, Ava, sat at opening of this century and pitted with righteousness and unholy greed seemed to my side. frightful force planet against planet, is be ending with victory on our side. As In these days, when a journey to another already becoming a mere tradition -a grue- the real character of the war had become planet is as common as a week -end trip to some, historical record of the unwise past. apparent, one after another the planets had Tapan was in my time, the presence of As you glide Venusian wo- along the turbid men in our so- canals, on your cial life is ac- summer trip to cepted as a mat- Mars, with the ter of course; peculiar reddish but in 2011 their water lapping at ethereal glory the sides of the still held us en- blunt - shaped thralled, a n d gondolas, y o u Ava -Ava was pause for a few the quintessence moments to of them all. contemplate the I was one of enormous mag- the committee netic pillars appointed to in- from which terpret the were launched Earth to the the world - visiting c o m - crushing elec- missioners, but trites ; or you I interpreted it climb the grass- only to Ava. covered Battle H e r presence Hill on Venus had called forth to gather sou- in a flash my venir fragments very soul, and I of the crum- laid it at her bling Flame feet with such Tower, whose generous inten- battered sides sity that she ac- now seem to be cepted it as gra- sinking into the ciously and as crest of the hill. sweetly as a But, strive as child takes a you may to re- flower. Ah I vive the images that lilt in her of that bygone voice-the mys- age, your inter- terious, fasci- est is only his- nating chime of torical and you the bells on her cannot sense the wrist -the bells the feeling of that no one horror that could see -the comes over us bells that were older people to save us from when we re- the Martian visit these time - horror ... But scarred, battle - I am forgetting seared scenes of the reception a past in which and the sum- w e struggled mons of the against c o m - pocket phone. p l e t e extinc- With an im- tion. patient jerk I I do not ex- drew out the pect, therefore. phone, set the to reproduce in silencer so as your souls the not to disturb emotions t h a t those near me,

moved me . in and adjusted that time of the receiver to strain and . . 'The Bells Are Inside,' Ava Explained." my head. Im- stress -I cannot mediately I hope to picture could hear In- in your minds my own mental conflicts of joined the forces pledged to destroy the gals, my managing editor. His voice was dread and triumph, of life and love and menace of Martianism. The huge V- planes tremulous with excitement. hope. when a fear -maddened universe of the Allies now surrounded Mars in a "For God's sake, Elvan, hurry back!" he fought desperately against a new force - flashing ring, gradually crushing down her gasped. more bitter and relentless than any that stubborn resistance, and we looked forward "What's up ?" I asked. warring mankind had ever before faced - with eager hope to the approaching end. "I can't tell you- hell's broke loose on the Invisible Armada of the Air. But I Then came the stupefying shock of Phila- Earth!" Want to bring vividly to your minds the delphia's destruction. "Won't tomorrow do ?" I suggested. knowledge of that event, one among a I was in Paris at the time, representing "The Honorable Peros -" thousand of the Great \Var, so that you the New York Century at the reception to "Oh. damn the Honorable Peros !" may see how the Supreme Intelligence, the Commission from Venus. Around the shouted Ingals. "Start now, I tell you." working thru the mind and hand of man, table of honor were gathered the keenest And he shut off with a jerk.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 759

I glanced around at the assemblage, at "Impossible," objected one of his ceived a message calling me back to New the venerable high commissioner, now auditors. "The V- planes are hedging Mars York, but there were no details." fully launched forth on his impressive mes- so close a fly couldn't get thru." 'There are all kind of rumors. One sage and, finally, at Ava. An inexplicable "That's what they said in twenty-ten," says Philadelphia is gone. Another tells fear, vague and uneasy, wound like a cold, sneered the Mercurian. "Then the electrites us all America is wiped off the Earth. thin wisp of steel around Whatever it is, this is no my heart. With quick re- time to stand back in fear. solve I drew out my note- I'm going over." book to find the index sign We look upon the present World War with awe because we know it to I fell in with his stride of the American Air Ser- be the biggest conflict the world ever saw. But Napoleon's wars, Alex- as he turned, and we vice. In another moment ander's wars, no doubt were looked upon with exactly the same kind of walked aboard the Eagle, I was talking to the man- awe by the then existing humanity, because those wars were the biggest whose powerful blades ager. There was a night up to those respective times. were already slicing the express leaving London, What of the future? Suppose the Martians, whose civilization is in- air. he informed me. Whis- finitely older than our own, one day take it upon themselves to conquer At sunrise the next pering a hasty explanation the planetarian World, in order to keep their race from extinction, on morning, as the Eagle to Ava, I made my way their dying planet? It's only a step further from the present Hohenzol- soared across Staten from the hall up to the lern idea. For some day the gulf between the planets will surely be Island, I stood on her roof of the building. bridged. What then? Read this intensely interesting story of the future. dew -wet forward deck and About a dozen planes We guarantee you will like it. gazed ahead with a pecu- were lined up on the liar sense of vague fear as starting platform and I to what sight might greet selected the swiftest look- me. I gave a gulp of relief ing one of the lot. It was a long, grey began slamming us. I tell you, the Martians as the outlines of the great city flew rap- Bullet Racer. The aerist, a light- hearted have outguest us again. You listen to me- idly into vision. Before I could dwell any boy still in his teens, assured me he could the Eagle won't get half way across. Take further on the meaning of Ingal's message, make the station on time with half his my advice and stay here." the great airship began settling toward her cylinders dead. If it's the Martians," observed a placid dock. Watch in hand, I crept into the asbestos - voice in back of me, "they'll hit us here Without a moment's delay I hurried to covered compartment, seated myself by his just as quick as over there. I can't see the Century Building and soon was wind- side and we slid into the night. In a few the sense in getting scared off the Eagle." ing thru the long lane of writers' desks to moments we had cleared the city and were I turned with a smile of approval to face the editor's office. heading straight for London. Instead of the speaker. As I suspected from the ac- Again a feeling of undefined apprehen- following the well- marked route over sion chilled me as I opened the door and Calais we took the direct Dieppe path, Ingal's tired eyes met mine. No sleep had 11 ill lIIIIIIINIiI IIÍ4111 ,inill6illlil plilbÌ li.3 hoping to gain a few precious seconds by -21111111111111111111111011111113M, closed his -the pupils were pin points in the lessened mileage and the lighter traffic. THE "E. E" two sunken, blue -grey pools. For five minutes we breasted the darkness IN APRIL "Elvan! Good!" A look of relief lit up with no sound but the purr of the motor = The April issue of the ELECTRICAL his drawn features and he leanad back in and an occasional click of the altitude lever EXPERIMENTER will be replete with his chair. "For the love of glory, Elvan, as the plane rose or dropt to escape the numerous timely and valuable articles get over there quick and give us a straight suction holes that our indicator showed us B on Electricity, Radio and Chemistry story of this convulsion,' he implored. in advance. Then a light flashed out of 7 of interest to all readers, both oung "You're the only one can do it. All the the black, winking red and white. It was and old. Don't miss it. It will pro- tykes around here have gone insane, I be- the signal station at Dieppe, floating ten vide many hours' instructive reading. lieve. Look what this putty- brained ass thousand feet above the city. Half the AU the latest advances in Science says -" He held up one of the scribbled distance was behind us and I had ten min- will be there -as well as fresh news sheets and read from it in a voice ragged utes left. I turned to my companion with and pictures from the war front. with exhaustion: " 'No such scene has a murmur of satisfaction. Among the April features scheduled 7 ever been seen before. The scene beggars "You'll do it," I said with satisfaction. there appear the following: description ! "" "It's easy," grinned the boy. "Last year Warar with the Invisible" -con- M "is it as bad as all that ?" I asked soberly. I pushed a V to Mars. There's where the 7 elusion of this gripping story of war "It's worse," Ingals assured me, becom- lads move. A hundred a minute with the and science, by R. and J. Winthrop. á ing grave. "Philadelphia is buried a mile deflectors off and five hundred when they're deep and Lord knows who's next." "The Phenomena of Electrical Con- you on. I'd be there now if they hadn't duction in Gases.-What is Ionisa- "Surely, don't expect -" - "I certainly do. Those vampires smashed my back." tionp " -by Rogers D. Rusk, M. A. of I turned with a look of inquiry toward _ Mars -" his arched spine. "Research and Its Importance to M Mars!" I started in surprise. For the "Chunk of 'lectrite," he explained. "A Human Progress. " -by Dr. IV. R. temperamental Mercurian to be seeing Mar- grain of it humps you up." Whitney of the General Electric - tians behind every catastrophe was quite A As we sped over the Channel the cloud Co.'s, Research Laboratory. spe- natural, but Ingals- "How could they ?" that covered the sky opened towards the = cia! article which every American I protested. west and I could see Mars glowing dull should read. W- "1 don't know. That's what I expect you red, like a baleful eye on the horizon. "Elcctro- StaticExperiments"-Part to find out." His voice rose in grotesque "Whatever has happened in America," I 11 -by Frederick Von Lichtenow. wrathfulness. "Don't stand there theoriz- thought, "at least, it can't be due to the "AnewElecho- nwgneticShip'slag:" o ing, you blue- headed son of an inkbottle! Martians. Thank Heaven, they are bottled "A marvelous Electrical Tobacco Get on the job! If I don't soon have up securely." mLeaf by H. Hartman, C. E. something sensible to work on I'll go Sorter" toppy" My ruminations were suddenly checked "How Electricity Changes Modern as his motor and pushed Some ten minutes later I stood on a the aerist snapt off Stage Scenery Instantaneously " -by the snub nose of the Bullet at a steep angle = little height in what liad once been Fair- towards the earth. We had reached George Holmes. mount Park, gazing down on the starkest London. E"Flow Science Takes X-ray desolation that the Earth had witnest since The immense dock of the American Air Movies of living bodies by the aid of b Sodom and Gomorrah. Where once five Service was thronged with excited groups Electricity." million human beings had lived and loved of people. Rumors of an awful cataclysm "The Chemistry of Selenium'- n and joyed and sorrowed, a vast body of in America were being stridently discust, What Happens in a Selenium Cell" =a sluggish, oily water stretched before the and many passengers hesitated to board -by Albert IV. 1Vilsdon. eye. The entire southern part of the city the Eagle, which stood ready on the in- "Experimental Physics " -Lesson had either sunk or vanished into the air, clined platform, her black, carbonoid body 12, by John J. Furia, A. B., M. A. and the Schuykill and Delaware Rivers, spotted with even rows of lights from the 7 rushing together, had converted the site "Vavenneters-Their Uses and Con- into an inland sea. observation port holes. struction," Part II M. W. Sterns. One Mercurian had made himself the -by Up towards Germantown and Ogontz, spokesman for the timorous, and loudly ex- "The New Electrical Laboratory where the land was hilly, the water had prest the fears that animated them all. 0 and Price Story Contest." not entirely covered the ground and a few "Don't tell me it's an earthquake," he was heights projected above the surface, barren III III Ilflll Inlll II 11 Ill t° shouting with the volubility and exag- I I111n111111111111111I111111III IIIIIIMVIC®10NVIM of any habitation or other sign of life, gerated gestures that mark the speech of and showing by their tortured appearance his people. "Whoever heard of earth- cent, he was a Jupiterian, huge in bulk and the agony of destruction thru which they quakes around Philadelphia? It's the glittering with gold leaf and jewels. had past. Martians. They've broken loose again." "What has happened ?" I asked. "I re- (Continued on page 803)

www.americanradiohistory.com 760 ELECTRICAL EXPERIMENTER March. 1918 Experimental Physics By JOHN J. FURiA, A. B., \l. A. Columbia University

LESSO\ 11 the third as in (c). etc.. for all eight discs. now he used both for 'dark room" and If now they are placed one on top of the other purposes. Two dry cells are re- Photography (Concluded) other and fastened at the left in hook form quired to run it. Turning switch to F gives by paper fasteners. on running the leaves red light and turning to I; gives white light. N lesson 10, the important elements en- quickly with the ringers, (because of the Experiment 62: -The retaining of the tering into photography from the stand- persistence of vision) a moving piciure of image after it is formed falls entirely in Physics were discust in detail, the radius is produced. The moving picture point of the field of Chemistry and is based together with the elements of color produced on the screen by production thru on the principle that chemical action is often Our chief consideration was the complicated machine in the theatre oper- theory. caused by light. For example, the fading obtaining of the image, either reduced ator's booth is simply enlarged views of the the of dyes is caused by the chemical action objects in successive series of slightly dif- induced by light. The formation starch ferent positions. of In the ordinary black and white photography most of the operations must be performed in a safe light, red in color (reason Pnvnnry ..- to be given later). The following little lamp mired, or-,. GóØKD.O n//h:,-. can be constructed at a very low cost and qiveop/^ e .. will give satisfaction in even the most deli- nhile cate work. A box 6" by 6" by 4" should be made of 1/4" wood and the ends joined and glued so as to be light- tight. A grooved ;O'C>> frame is made for the front, three parts of Si.S: which are rigidly fastened together and the When the Colors Indicated Are Mixed, by fourth fitting Rapid Rotation, the Effect of "White Light" tight but not fastened. A piece Is Produced. of window glass can be cut to fit and Series of Simple Pictures, Which, When Pre- to the Eye In Rapid Succession. Give the in and sented from elements stater irons car- the Effect of a "Moving Picture." bon dioxid which is breathed out by human beings, occurs in the leaves of plants only the influence so we see or enlarged as required. In this Lesson, in tinder of sunlight, that most all chemical order to conclude the subject. most of the the important of actions (since life depends upon it) is space will be devoted to the retaining of the caused image even tho this phase of the subject by light. If equal volumes of ferric falls chiefly within the realm of Chemistry, chlorid and oxalic acids are mixed in the then (It should be noted safe red light of the "dark room" and rather than Physics. ferricyanid here that because of the close relationship an equal volume of potassium changes but between Chemistry and Physics, one can added, the color slightly. lf, rarely treat of any topic in one of these however, this same process is carried out subjects without bringing in the other.) in daylight the result is a pronounced blue 61:-When an ignited piece color. The ferric chlorid and oxalic acid Experiment red is rapidly- rotated, we cannot when mixed in the dark or safe light of charcoal daylight distinguish it. but, however, the appearance do not react, but when mixed in K do react and form another compound -fer- of a circle of fire is produced. In a similar manner, rain. tho falling in drops, appears rous chlorid; whereas ferric chlorid on be- the Effect of on Silver Bro- ing mixed with potassium ferricyanid does in the air to be a series of liquid threads. Showing Light mid (b) After Adding Developer. Solution (a) not react, ferrous chlorid and the re- This phenomenon is due to the persistence does, Not Exposed, Hence Not Changed by De- is compound called of vision. The explanation is that the im- veloper. sult the "Turnbull's This illustrates the process of blue- pression of an object on the retina of the blue." printing. The blue .print paper is coated eve remains for some time after the object a glass can with a compound similar to those mentioned has been removed or displaced, so that stained, or else piece of ruby be to the manufacturer) and when the speed of the motion is sufficiently purchased for a few cents. The fourth above (according light strikes it a chemical change re- is seen in its new position part of the frame is not rigidly fastened when great, the object trashing with water where light while its image in the old position is still sults. On the paper it changes to Turnbull's imprest on the retina. It is this principle struck unchanged material is washed of the persistence of vision that makes blue, and the motion pictures possible. Cut eight squares away. of heavy manila paper two inches on the Experiment 63: -(To be performed in side and find the exact center by faintly dark room.) Take equal amounts of silver drawing the diagonals of the square. With bromid solution in two test tubes, (see Fig. these points as centers, draw circles with a 56). Make sure that none but the safe radius of one -half inch. On the first, draw "red light" strikes the first test tube (a) heavily- its radius in position indicated in and expose test tube (b) to white light. figure 54 (a). on the second as in (h). on This Illustrates the Photographic "Negative" Solutions of these chemicals are to be used. and "Positive." Note That Either Is Nega- (Continued on page 799) tive and the Other Positive.

for convenience in getting at the inside of the box when necessary. ln the center of the back (inside) a miniature socket and three volt lamp are attached and a similar socket and lamp on the top (outside). A pair of binding posts are then attached on the top and a two -point switch (consisting of three thumb tacks and a piece of metal) is attached on one side. Connections are made as in figure 55 -11 (A and 13 are the binding posts: C and I). the lamps and E. F. G, the three point switch). To make a real good job it the inside of lamp of the This Highly Magnified View of Plate Used for Simple HonteMade Duplex Lamp. Handy for can be enameled white and the outside Color Photography Shows Probable Arrange- Dark Room and Other Purposes. stained and varnished. This little lamp can ment of the Colored Starch Grains.

www.americanradiohistory.com March, 19I8 ELECTRICAL EXPERIMENTER

Notice to All Radio Readers

ils utosl )f our radio readers are undoubtedly aware, the t'..1'. Government has decided that all Amateur Wireless .s to- lions, wliefher licensed or unlicensed, or equips for receiving or transmitting, shall be closed. This is a very important consideration, espeeially to those who are readers of the ELECTRICAL EXPERIMENTER. for the reason that eve desire to continue to publish valuable articles on the wireless art from time to fine, and which may treni on both transmitting and receiving apparatus. in the first plow, there are a great many students among our readers who will demand and expect a continuation of the usual class of Radio subjects, which we have publisht in the past four years, and secondly, there will he hundreds and even thousands of new radio pupils in the various naval and civilian schools ihrriout the country, who will be benefited by up -to -date wireless articles treating on both the transmitting as well as receiving equipment. Remember that must not connect rip radio apparatus to any form of ailenno. -The Fditors. An Exceptional Amateur Radio Station

WAR i, \ \ar we all know that. But thing " -enlisted where his services can be professional >hle The tranuttmmg plant look at the accompanying set of of the highest value to hi, :omttrv. \\e was a beautiful and efficient piece ut work. photos showing some of the glories present the accompanying photographs thru including as it did a Pt: K.W. transformer, of amateur radio slays before the war. the courtesy of his father -a co- partner in oil condenser, interchangeable rotary spark This represented the magnificent wireless gaps. radiation meters, et cetera. station operated by 21 -year -old John H Mr. Stenger built an extra large Tesla Stenger. Jr.. of 117ilkcs- Barre, Pa., in the transformer which he excited from hi- palmy days just prior to last April. Radin radio step -up transformer, condenser and amateurs in the east w ill probably recall rotary spark gap. it gave sparks 34" long

r-I T..`4f J'I rMry,=,u These Photographs Show Vividly the Home -made Equipment in One of the Finest American Amateur Radio Stations Existing Before War Was Declared. It Was Owned and Operated by 21- Vearold John H. Stenger. Jr., of Wilkes- Barre, Pa., Who Is Seen Above in His Uniform of "Electrician-Radio." U.S.N. the station who used to answer to S.Z.S. the enjoyments formerly afforded by this I I. F. N -Ray equipment was also on bowel The station was dismantled April 12, 1917. excellently equipt radio laboratory. '¿'here The receiving equipment comprised a in obedience to the President's proclama- w'cre many such stations thruout the coun- 2 step tubular Atidion amplifier. experi- tion. Its operator, John ti. Stenger, Jr.. try that ambitious and ingenious American mental apparatus. etc. The antenna was a enlisted in the U. S. Navy May 1, 1917, as buys had perfected and built. Ilere is large affair and very well built. It was landsman, electrician- radio. He is now al where the "ideas" were evolved and now supported by a 40 ft. chestnut pole. sur- the U. S. Submarine Base, New London. the country benefits. mounted by a 00 ft. steel tribe. giving 100 Conn., as Electrician- Radio, U. S. N. His Look at the details of this particularly ft. elevation. The aerial contained 10 photo in uniform is shown herewith. high grade experimental wireless station wires, spaced 2 ft. apart. and measured Youthful al r. Stenger has clone the "big here illustrated It w as fitted out in true 01 ft. long. spreader to spreader.

www.americanradiohistory.com 762 ELECTRICAL EXPERIMENTER March, 1918

WIRELESS STATION IN FRENCH between them. An illustrated slide was as aerials, but it did not answer very satis- TRENCH. here shown and the crowd of curiosity factory and this scheme was drops The present illustration shows a radio seekers about the radio -car almost swamped Later a regular research laboratory was station and the operator standing outside the small car and its operators. This car establisht on wheels, being in the same class the dugout in a French, second line trench. was kept in the yards and experiments were as the safety and other exhibition cars. A made from the labora- pullman dining car was made over and a tory located in a small large aeriel set a few feet above the roof. shop nearby. it was pos- Also at one end a collapsible mast capable sible to sound various of extending about 80 feet was fastened kinds of warnings on the for experiments on sidings. A large gen- car and to start, stop and erator and a gasoline engine were installed reverse its motion by to furnish power. One end was partitioned Radio. An arrangement off for sleeping quarters. The rest of the was also worked out so car was devoted to the experimental labora- that a tower man could tory and judging by the lantern slide shown send a signal and an au- of it, it was some class! With carpet on tomatic arm or light the floor, rest chairs and what not -well it would operate and warn certainly looked more like a grand salon! the engineer in the cab. Nevertheless much important work was But this nearly always accomplisht, and exhaustive tests were made failed to work at a and charts calibrated of results. The ten critical moment and not years of experimenting fell thru when war the some few thousand was declared and the laboratory hung out times in succession that its shingle. "closed for the season!" The is required of a device paper was a change from some of the which is to be practically technical papers that have been read and adopted. Dr. Millener's personality did much to get At this juncture in the the "high- brows" in the audience in good game certain patent suits spirits and all of those present appreciated started, claiming in- his coming East to speak before the In- fringements, and there - stitute on so interesting a topic. fore the work was abandoned for a time, also certain needed ap- TEACHING U. S. AVIATORS portionments didn't quite RADIO materialize in the budget. -TELEGRAPHY. After a time work was "Learn to do by doing" is the motto of again resumed and better Uncle Sam's new military aviation service. quarters were fitted up And let no one tell you that action is not and a number of stations suited to the instruction. One of the first erected along the main things new recruits have to do is to learn line of railroad ; these wireless telegraphy. Mark the application maintained direct connection of their motto: They learn the art by talk- constantly. Work one another by wire- was also done in Radio- ing across tables with telephony and a number less. Here is a class in action. An ais man's in learning the science of radio, [`bozo © by In eruulonal Film Senice of arcs of different types first step which he will shortly be called upon to use in a Second Line French Trench We Find Thls Interesting, were experimented with. Battle -Front Radio Station. The Aerial Is a Low Affair, so as Also some were tried over the German trenches in France, is to Not to Be Easily Seen by the Enemy. The Apparatus Is with in master the International Morse Code. The Placed in the Dug -out at the Right. gases contained the surrounding cham- men here shown are cadets at one of the ber; a disastrous attempt "Ground Schools" practising the sending of These men are almost continually under at using illuminating gas put the gas idea dots and dashes, which are immediately re- bombardment the enemy making every ef- out of the running. the tape before them. This aerials. produced on fort to destroy the stations and the The Radio -phone worked fairly Well be- permits them to lengthen or shorten their The aerials extend but a short distance tween the establisht land stations but some until wholly accurate. The the trenches of course, as motions they are above the top of difficulty was experienced with the set in- Radio to the thousands of new becomes clear from the photo, as other- stalled on the train. The voice had a teaching of wise they would soon be destroyed by shell peculiar manner of dying away suddenly aviators now being schooled by Uncle Sam or machine gun fire from the enemy. The and then after a time coming back again. is a man's -size job. Radio instructor offi- radio apparatus is located in the dug -out It was also tried in conjunction with the cers have been recruited from civilian walks shown; note the heavily reinforced roof of then existing telegraph lines, using the same of life for this purpose, in many cases. sand bags to withstand shell fire. Some of these dug -outs form entrances only to an elaborate underground operating room or gallery. This gives better protection and less interference due to noises from shell and rifle fire. DECEMBER MEETING OF THE I. R. E. A very interesting paper was presented at the December meeting of the Institute of Radio Engineers at the Engineering Socie- ties Building. New York, on December 5th. Many notable radio men were on hand and the attendance was large, mostly due to the fact that the paper had a good advance notice and the interesting topic of "Radio- telephony on the Union Pacific Railroad" was disgust. Dr. Frederick H. Millener, the author. described with many amusing incidents the work of almost ten years spent in experimenting and installing wireless telegraph and telephone sets on moving trains and in main stations. The first researches were made on a specially constructed flat car, about ten feet in length, and weighing a couple of tons. non) (e by International Film Sertira fitted with storage cells and other apparatus. How Uncle Sam's Aerial Fighters Learn Radio. They Practise the Dots and Dashes at On each of the cars were set two short poles First, the Signals Being Reproduced Before Them on the Tape Registers. This Allows and a crude four wire aerial was strung Them to Check Up Their "Sending Fist."

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 763 Visiting Arlington via the Talo Club By W. J. HOWELL

IT all happened along about the time southern "ether" and it was needed in its was waiting to make the trip to Arlington, that "Arlington" was first put into thermal form because it was rather cold and we piled on. operating condition, that the members down there in November. Daylight at last Passing over the Potomac River and into of the Talo Club got the idea that they came in all its glory and made me think Virginia, was a short trip, but we nearly wanted to visit the place and see for that the sun -dodgers of our town miss killed "Mac" because the car went right themselves just - at really was down there something when they sit tip until all hours past the Monument, and while there we that made so much noise in the 'phones at listening to radio signals and then turn in had asked "Mac" if it was the one we were ten P. M. every night. To think was to just as it gets light. Washington very looking for and, of course, he said no. act, and it was found that one of the East- shortly was reached and we piled off. thereby making us use some more leg power ern trunk lines was running excursion trains After washing off the "real -estate" of in order to find it. Pretty soon the conduc- down to Washington and back to New five states and one district, we started out tor yells out 'Radio," and we found our- York, thereby giving about ten hours in the and kept our eyes open for a place to selves jumping off at a little two -by -four Capitol to see the sights while the cost fill up our insides, and believe me, we felt wooden shack with a sign that stated that would be in the "Amateur" limits of money, in the need of something after walking, this particular spot was what is known in which in this case was three cold dollars. for Washington apparently got a divorce the amateur world as "Radio, Va." There were four of us who went, and a from itself, because one has to walk a long Crossing the track a path led us down slight mention of each into a small depres- one will not be amiss. sion, thru which past "Woody" was the big a stream of water guy who had the repu- which kept the tation for wearing grounding system sand -paper collars, in moist, but at the time other words, a rough- of our visit we found neck, while "Mac" that when crossing the was an expert brass little foot bridge the polisher at one of our stream tried to moist- leading hotels. Then en the footal supports there was "Dickey," of the party, besides the Secretary of the keeping the buried outfit, and myself, copper wires in work- w h o unfortunately ing condition. At the had to hold down the top of the slight rise job of President, be- was the radio station, cause none of the and altho we had seen bunch wanted the it before crossing the honor and they had track and had taken to have some one to pictures of it, the blame if things went bunch took some wrong. more, for it certainly Well, it was decided was worth all the to beat it to Washing- trouble of getting to ton and that we meet Washington just to at the station and look at those towers. take the mid - night Pictures that h a v e train, arriving there been publisht do not about six A.M., Sun- show the spectator day morning. Of the real thing and course, we all brought Going Outside to Watch the Antenna 'Spark,' Which it D Idn't, We Found the make him feel that Famous Aerial Switch, Mounted on Two Short Poles With a Ship's Bell Attached. Guess something to eat, but They Ring the Bell When Signals Come Down the Lead-in." Author Is Central his own little aerial "Mac" was the win- Figure In Photo. at home is a mere ner of the first prize, bird cage compared for he came with sandwiches made of time to even cross the street. During this to the one before his eyes. slices an inch thick, and butter enough to time we had about twenty fellows with all Climbing upward we came to the main feed one at the present "Hooverized" rate kinds of automobiles ask us to allow them building and walked boldly in all the while for an indefinite period. The ham was in to show us Washington for the mere sum of expecting some one to throw us bodily out, the same class, and upon our requests he a dollar a piece, but there being four of us but nothing happened, so we gathered cour- mentioned that the food supply was gotten and Audions about the same price, we de- age and started to inspect the plant. For- by talking to the cook and appropriating a cided not to indulge. At last "fter much tunately "Mac" had been down before, and little at a time. What he talked about we hunting we discovered Bryant's Lunch while there, took some pictures and became couldn't find out, and it must have been Room about four blocks from the Capitol pretty well acquainted with one of the op- exceedingly interesting, but at any rate, we building and stopped there to eat, but we erators. In the mean time, he had had the helped "Mac" to eat what he had and often look back and wonder if Bryant was pictures enlarged and brought them along, saved ours. I brought some steamed in the food business at the time. Break- all of which made things somewhat easier chestnuts, but the jokes that were pulled fast being finished we got under way and for us because, as I look back, I don't off were enough without having to eat them looked over the Government buildings think that we would have been allowed to besides. there -about, but the aerial on the Bureau wander over the place just as we did, with- 'Long about this time the train started, of Standards attracted first attention while out being told to beat it. That is. unless we but not before a meeting had been called off in the distance could be seen the Wash- could have managed to scrape up acquain- to order and more work done then in a ington Monument and the Towers of Ar- tance by trying a little of that "mental short time than we ever did formerly, but lington. telepathy" stuff. It works- sometimes. the idea that we were starting broke up Passing on down the avenue we came to The main transmitting room at that time this business stunt and we tried to get as 14% street, and while we found the street contained the large 100 K,W. set and a small little sleep as possible while passing thru all right we couldn't locate the half, so we arc outfit, besides a regular 5 K.W. set for Trenton, West Philadelphia, Wilmington, curbed our interest on that pavement and ship work only. The ' receiving room" was Baltimore and other small towns along the wandered on looking for a car that "Mac" in the next building, and was built like an right of way. About five A.M. "Dickey" and said would take us to Arlington. icebox with walls two foot thick. The two I took a little trip thru the train, and as Well, we walked and walked some more buildings stood about three feet apart so we were in the second car, and the outfit and still no car, but our trip took us past that no sound of the transmitting set would consisted of ten coaches, we had a good the Monument which was not open for bus- reach the operator in the receptor room. chance to see the human animal at sleep, iness, altho it was an early riser and was Two men are always on duty, one in the for believe me, the shapes that people can up when we got there. Looking at the top transmitting room and one in the "listen- get into when sleeping in day coaches gave us a permanent bend in the back of ing box," and when the fellow hears a sta- makes one wonder if their hair hurts when the neck and was good training, for we tion calling him, he signals to the fellow they bend it 1 sure needed aid in finding the top of the outside, and he in turn starts up the S K.W. \Ve ended up at last on the back plat- Radio Towers later on. Walking on from set and stops it when signaled. A relay is form and watched the sun break thru the there about a mile, led us to where a car used so that no high voltage wires pass (Continued on page 800)

www.americanradiohistory.com 764 ELECTRICAL EXPERIMENTER March, 1918 The Design and Use of the Wave -Meter

Part 1 -By MORTON W. STERNS

THE Wave -meter is an instrument condenser rises to a value sufficient to Fig. 3 represents a damped wave dis- used to measure and detect the break down the gap G. the condenser will charge of the limit allowed by law (logarith- length, frequency, and amplitude of discharge across the gap and set up oscil- mic decrement 0.2) which require 24 com- emitted oscillations. Essentially it lations in circuit 1, of a frequency de- plete oscillations before the amplitude of consists of an inductance connected pending on the values of L and C. the last oscillation is reduced to one per in series with a condenser, either or both If now another circuit L'C', consisting of cent of the first. It is discharges of this of which may be variable. For standard an antenna having a capacity C' with re- type that are in use the most at present. spect to the earth, and an inductance of a They are produced by quenched and rotary value I_', is brought near circuit 1 (i. e.. gaps, etc. Waves of this type are received coupled to it) energy will be transferred on ordinary receivers using crystal, plain from the first circuit to the second circuit Audion receptors, etc. by pure transformer action. If the values Undamped waves are represented by Fig. of L'C' are adjusted so as to give circuit 2 4. Here we see that there is no damping the saute frequency as circuit 1, then (ig- or decay between successive alternations noring gap action and coupling) the great- but that they remain of a constant ampli- est amount of energy is transferred from tude. fá I circuit 1 to circuit 2, and an ammeter Waves of this type are coming more and placed in the ground lead of circuit 2 will more into use, especially for long distance Form The Simplest of Oscillating Circuit register the maximum 2 communication. As can be seen they repre- Comprising a Capacity "C" and an Induct current or circuit ance "L." Connected in Series. The Basic is said to be in resonance with circuit 1. sent a continuous flow of energy and are Circuit of the WaveMeter. The last paragraph demonstrates clearly produced by the arc, Oscillion, radio fre- the principle of resonance on which all quency generator and other means. In re- wave- meters of great precision the oscilla- wave- meters and decremeters work. ceiving these waves a special type of re- tion constant 1/LC is generally kept con- We will now proceed to show how the ceiver is required, embodying either a tikker stant in order that the decrement of the values of inductance and capacity affect the to break up the waves, or a separately instrument shall remain constant over its frequency of the oscillations in a circuit, variable source of oscillations (such as the entire range. This is done by making both and hotu. knowing any two of the three oscillating Audion) to "heterodyne" or pro- the inductance and capacity variable, i.e., factors (wave- length, inductance, or ca- duce beats with the incoming waves. by fastening a variometer to the condenser pacity) the other can he found. Referring hack to Figure 3, we shall con- shaft. The type of wave -meter generally The wave- length (X) multiplied by the sider what the Logarithmic Decrement is in use at present is the variable capacity number of waves per second (n) must and how it is measured. Each wave train type, hating numerous coils for a great equal the velocity of propagation (V). is composed of oscillations which are sup- range. Formerly. the wave -meter having or V =nr (1) posed to die away so that the ratio of any a fixt capacity and variable inductance was oscillation to the one preceding it is con- much used. stant. as the ratio of A'to A. It is generally conceded that the Wave - This constant ratio is known as the damp- meter is the most valuable instrument in a ing of the circuit and the Naperian loga- Radio Laboratory as it can be used for:- rithm of one oscillation to the one preced- 1.-Measurement of wave- length. (Trans- ing it is called the Logarithmic Decrement mitted or received.) . of the circuit. 2.-llleasirement of decrement. A 3.- Measurement of inductance. Exprest mathematically a = log e - 4.- 111casurenient of capacity. A, 5.- Making resonance curves. \ \here a = Logarithmic Decrement 6.-Making various antenna measure- and e = base of Naperian Logarithm, ments. (2.71828). 7. -An exciter emitting st'azes of prede- ,C[ The logarithmic decrement determines to termined length. o a great extent the broadness of tuning and 8.-Measurement of mutual produced. inductance. Diagram Showing How Maximum Current the amount of interference 9.-Measurement of the coefficient of is Developed in An Inductive Circuit -C 1, 2, Hence the U. S. Government's limit that n' coupling. A -When Such a Circuit is Tuned to "Reson- transmitter shall produce waves having a 10.- Measurement of the distributed ca- ance" With an Exciting Circuit -C, G. L. greater logarithmic decrement than 2. pacity and natural period of coils. An instrument whose purpose is to meas- These various applications of the wave - Where V is the velocity of propagation of ure the logarithmic decrement of a circuit meter will be taken up in clue course. radio waves (the speed of light) 300,000,- is known as a decremeter, which is nothing Having imprest upon the reader the im- 000 meters per second. more than a wave -meter with an indicating portance of the wavemeter, its great instrument in circuit to indicate current adaptibility and various uses, we will now ratios. More will be said about the decre- n = (2) undertake a general review of a few ele- NI meter and its uses in the following install- mentary principles in order to make the 2 17 LC ments. paper intelligible - to the great number of expressing L in henrys and C in farads. Suppose now we are to design a wave young men just taking tip meter having a the subject of Equation 12) can he found in any text range of from 200 to 3,000 Radio at the various schools of the Army book on and Navy, Alternating Current. as well as radio students in Substituting in Equation (2) the con- general. stants Realizing necessary to change L to centimeters the breadth of the field to be and C to microfarads we have: covered in the space available and the necessity of keeping the paper very ele- 5.033 X 10° mentary. it is to be expected that certain N = ,opics may be neglected. L,,,, Calf Figure 1 represents a simple circuit consisting of an inductance and a capacity Putting the value of n back in equation (1) con- we nected in series. 1f the condenser is have: charged to a given potential and then al- 5.033 X 10° lowed to discharge tltru the inductance, os- 300,000,000 = a cillations will be produced whose frequency Ni Lem Cmr will depend upon the value of the inductance L, and the capacity C. or X meters = 59.6 I r Let us now consider this simple propo- \ CM, (3) sition with respect to a Radio Transmitter Equation (3) is known as the funda- as shown in Fig. 2. mental equation of radio and much use will Suppose the condenser C is connected be made of it in further papers. Principle of the "Logarithmic Decrement" - to some source of high voltage alternating Oscillations taking place in a circuit (or Each Wave Train Decays In the Manner current, such as the secondary of a step -up Shown, so That the Ratio of Any Oscillation emitted waves) can be of two kinds, to the One Preceding It Is Constant, as the transformer. When the potential of the damped or undamped. Ratio of At to A.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 765 meters, with 20% overlap between coils. and son we have the high upper range is be- in operation the tuner is held in the coat so designed as to give small distributed ca- cause the four coils are necessary to reach pocket. By pressing the buttons of the pacity, low internal decrement, etc. 3,000 meters and the upper range of the tuner, messages are received in the dots The first thing to decide upon is the con- fourth coil is 3,740 meters. This is gen- and dashes corresponding to the radio- denser; this is generally designed so as to erally not objectionable, but in case it is, it telegraphic code. give a variation of six times its minimum simply necessitates the selection of a dif- Contributed by HARRY E. FUCHS. capacity. By this I mean that the capacity ferent capacity variable condenser. at 175° on the condenser should be six times HY -TONE TESTER FOR MINERALS the capacity at 10° on the condenser. AND CODE PRACTISE. \Ve use this value because, as shown by Being a steady reader of your paper for the curve in Fig. 5, the variation of more nearly two years, I thought I would send than six times the minimum capacity of the you in a little stunt which i have been condenser does not vary the wave- length using and found very reliable and satis- as rapidly as the addition of a new coil. . factory. It is a high frequency tone device The condensers used in commercial wave - a for testing sensitive spots on crystal de- meters vary from .0015mí. to .003mí., but tector, and wired up as shown in attached .003mí. is generally used. sketch. By building up the felt pad, any The wave -meter is seldom calibrated be- range from ahout 300 to 1.000 cycles per low 10° or above 175° because the per cent i é second can be obtained, and it produces a capacity change per degree is so small that Jig C000Ci!v pure musical tone of constant amplitude and the tuning becomes too sharp for accurate strength. with no scratching or frying work. Graph Illustrating the Reason For Using a noises whatever. There are no adjust- In designing our wave -meter let us as- Wave -Meter Condenser Which Gives a Varia ments to make or anything to get out of Lion of Six Times Its Minimum Capacity. sume a capacity of .0005mí. at 10° and order. .003 mf. at 175° and make our inductance A five ohm telephone receiver is used the as coils conform to these limits. The next step will be to determine it takes less battery. operating on from two and this is We will now consider the coils which will size litzendraht to be used to three dry cells. A regular 75 ohm re- be made of the pancake type, wound with largely a matter of experience and keeping litzendrallt (insulated stranded cable, each the meter decrement low (3x16x38 litzen- wire being insulated) and banked by layers. draht is much used). Next a standard These exploring coils will be connected to mean diameter is selected so that the bob- the meter by a flexible 3% ft. leather cov- bins of all the coils are tlté same size; ered cord. and using Perry's Formula the number of The lower limit of the meter is 2(X) meters turns are easily calculated. and this is at .0005mf. (To he continued)

\ = 59.6 NU-C equation (3) "SECRET SERVICE" POCKET RADIO RECEPTOR. Where L is the inductance in cm. and C This is a "real" pocket receiving set, une that actually receives while you are out on the street or any other place. The set consists of a special tuner, condenser, detector, 'phone and an "invisible' aerial. The tuner is 4 inches long, 2% inches deep and 1% inches wide. As shown in the illustration, A is the wire of the tuner, B is a strip of spring brass, C is a knob of Clever Form of "Microphone Howler" For Radio Tests or Code Practise Work. It Gives D is a brass soldered to the spring strip. a Pure Note of From 300 to 1,000 Cycles, De- needle point (not steel) soldered to the pending Upon the Distance Between Micro. Fig 4 spring strip, E is the condenser (fixt), F phone and Receiver. is a detector made of a blown -out cartridge Illustrating the Principle of the "Undamped fuse as described in the April, 1917, num- Wave" as Used In Radio- Telegraphy and ber of the ELECTRICAL EXPERIMENTER. All Telephony. There Is no Damping or Decay the spring strips B are connected to bind- Between Successive Alternations. ing -post G by means of a wire. One end of the luire on the coil is connected to is the capacity in microfarads to gite a binding -post H. Selectivity is obtained on wave- length T. >,' = 3550 I.C. this tuner by pressing the buttons C. Xi The aerial is composed of a long flexible L wire sewed in a zig -zag way in the back 3550 C of a coat and insulated by empire cloth. 40,000 L= =22,500 cm. 3550 X .0005 Hook -up of Microphone Howler to Primary At the upper limit where C = .003mí. and of Loose Coupler "LC," So That Tuning May L = 22,500 cm. Be Practised in Natural Manner. X = 59.6 \ 22500 X .003 = 490 ceiver can be used, but this will require more battery, from 6 to 8 cells. This also Now to allow an overlap of 20c%. the makes an excellent wireless practise set. I minimum wave -length of coil No. 2 must wired it into my set with a small three - equal 80% of the maximum of coil No. 1. pole switch as shown, but almost any X = .80 X 490 = 392 meters at .0005mí. knife capacity. Therefore. hook -up will do. In connecting up the (392)` battery. however, it will only operate with or L 86,400 col the current in one direction, the cur- = _ the 3550 X .0005 rent must flow to build up permanent magnetism of the receiver and not neu- X max. = 59.6 \' 86,400 X .003 = 960 meters. tralize. Am sending you this idea for I know it works perfectly. with no trouble Following this method me find we need or bother whatever. four coils which are tabulated below, show- Contributed by CURTIS KISSELL. ing the individual inductances and range of wave lengths. RADIO CLUB OF AMERICA NEWS. The Radio Club of America held a meet- Inductance Nave Length Ser Coil No in cmc. Range A de Luxe Pocket Radio Set For Secret ing at Columbia t- niversity on October 27, vice and Like Work. Rapid Tuning Is Accom t 22,500 200 -400 meters pusht by Pushing on the Various Contac 1917. Two important papers were read, 2 86,400 3Q2 -160 " Buttons -One at a Time. namely. "Thermo Couples in Electrical .1 338,000 -10110 4 1.310,000 1377420 3740 " Measuring Instruments" and "Radio Fre- A ground is obtained by running a flexible quency Instruments" by Dr. H. O. Taylor It is, of course, understood that the rea- taire thru the trousers to a brass heel plate and Mr. Charles G. Kahant. respectively.

www.americanradiohistory.com 766 ELECTRICAL EXPERIMENTER March, 1918 The How and Why of Radio Apparatus

By II. «I.\FIELD SECOR. Assoc. 1. R. E.

No. 7 -Radio Receiving Condensers. showing a fixt condenser and B, a second terminal to the insulating medium, called From time to time we will describe one way of representing a fixt condenser, while the dielectric, and this dielectric is the mem- particular instrument used in either the ra- C shows how a variable or adjustable ca- ber that retains the charge, and not the dio transmitting or receiving set, explain- pacity is indicated, viz., by drawing an ar- metal electrodes. This being the case, and ing just how it works, and why. We have row thru the two plates diagonally. Fig. 2 as becomes evident, the capacity of any received so many requests from new read- illustrates the construction of simple fixt condenser depends upon the coefficient of ers asking for such explanations, that we and variable condensers. Fig. 2 -A illus- electrostatic induction of the dielectric. have decided to publish this matter in serial trates the construction of the simplest form This factor is generally called the "specific form. In the course of several issues all of fixt condenser, having a dielectric C, inductivity" of the material used as the of the principal transmitting and receiving charged by means of two tin -foil or other dielectric, and as a basis to work on, air is apparatus will have been covered. The conductive plates A and B. The metal taken to have a specific inductivity of 1 at subject for the seventh paper is RADIO charging leaves placed on alternate sides standard atmospheric pressure; the in- RECEIVING CONDENSERS. and in contact with the dielectric are always ductivity of any other substance is meas- cut somewhat smaller than the insulating ured by the ratio of the capacity of a con- pRACTICALLY all modern radio re- medium, to prevent leakage, and the pos- denser, when its plates are separated by ceiving sets employ some form of sible chance of short -circuits. The small that substance, to the capacity of the same condenser or capacity, either in the fixt condensers found in a great many radio condenser when its plates are separated by form of a definite fixt capacity or else receiving sets are made up of f rom ten to the same thickness of dry air. sheets, about in the form of a variable or ad- fifteen paraffined paper two This specific inductivity factor is also justable capacity. The aim of this install: by three inches, interleaved with alternately known leaves. Every as the "K" value of the dielectric. ment of the "How and Why of Radio Ap- charged tin -foil other tin- Any electrical or radio text -book contains a paratus" series is to describe.in detail the foil leaf is connected to a common terminal table of the various insulating mediums used as dielectric in building condensers and l&tob,'e Cone Cana' the corresponding "K" values. A very com- daim9Cone plete table of these values and of particular :'tede service to radio men, appeared in paper .!r. ... , "Ycnobtedie%/ f niefoccis No. 3 of this series (see Feb, 1917 issue) %XIOXC/ fUL1 and also contains the necessary formulae ,..,,,s MTh,/ for computing the capacity in micro -farads any condenser. . bl of (al ":" la- ç Resuming, Figs. 2 -B and C illustrate in fm/ plaies a simple manner how a rotary, variable, At( IOI O'd'cc%t ,fiL'OG^et7/ air dielectric condenser is constructed. A FL' one _ ;uhz central rotary knob and shaft have rigidly

t " mounted thereon one set of semi -circular .R.i'sry i. ,. plates, which may be turned so as to inter- .rr (b) fight, .-ir lr-w `*1' (b/ i%dic o ' rat leave with a corresponding number of fixt Iola' or stationary semi -circular plates. The condenser is provided with a scale which is - owls Pa.Cry sometimes calibrated to read in m.f., direct, % p ctes or else a calibration curve is supplied with Shaw/co/7d sly the instrument. Low- priced condensers are not usually calibrated, but the capacity may (C) ®)-dfu/h-hn9erb/ode be computed for any position of the rotary (C) .F fi,ipó`es Terms plates by means of the formulae in the -1- Z- -3- third installment of this series, above re- to. to the fixt iPrr7 ; O9pect3ted ferred One terminal leads a fo.'ts/r//1s plates, while the second terminal leads to 4et¢p7S x tc " the rotary plates of this type of condenser, .. ;Crm2 and in fact this applies to all other similar ., --. /.c,ny types of variable condensers. A variable r, DieTeYtnc - ïrii i i- p/v'es 1 l condenser of the moving cone type which -_ dz Red/edrond /+ \ _. has been used considerably in laboratory . .------1-oie/ednc /.r. type Ile. irr work is illustrated at Fig. 3 -A. This con- - fai condense denser involves the use of male and female (a) (a) conical members, arranged in the manner i'er cronee i Gle;b,'e f/e.nDle meta/ indicated, so that the inner cone can be de,rurr; , foil a c e aaiiny /4,77? raised or lowered by precision screw ad- - justment, and the distance between its end - _ and the bottom of the conical chamber of fixt as - 6 t the electrode, well as the thickness fiwt (6.1 of the air space surrounding the small cone (47,`'ana% p)o%s i' mt Yncb,e roller cone can be varied, and likewise the capacity. (b) Another simple form of variable condenser dj /b/ hit which has been used extensively in various \I s ri sets, 7'...""'e5 :ep e i, Ce.ét,rie types of receiving both domestic and foreign, is shown at Fig. 3 -B and utilizes VC I _ e _ _ . rB lc j r one fixt and one sliding brass member, or _ i.° a other non -magnetic metal tubes. The slid- 1 I ing tubular member is sometimes provided (e) with an indicating needle which reads over . sec/seeLir - ' -4- _ a scale secured to the base of the instru- Jir;. - 3G 175u/.5/la2 (C) - . . ment. This condenser has a fixt thickness /cJ 1 _h -6- -S- of dielectric, but the length of the active condenser insulation is variable to quite a The Principal Types of Radio Receiving Condensers Are Here illustrated and Their Action fine degree. and Use Described for the Benefit of the Student. Fig. 3 -C shows what is commonly known as an "adjustable condenser." In this form principal types of condensers found in mod- as at "A," while the balance of the alternate of condenser the capacity is varied by means ern radio receiving apparatus, as well as metal leaves are connected to the opposite of a special switch provided with a multi- their use and connection in these circuits. terminal "B." fingered blade, so that the capacity of each Referring to the diagrams herewith, Fig. Before going any further, it is well to unit switched into circuit is retained as each 1 shows how fixt and variable condensers note that the metal charging plates or successive unit is switched in. are represented in diagrams and hook -ups leaves of any condenser merely serve to of radio receiving apparatus; Fig. 1 -A distribute the electric charge from either (Continued on page 796)

www.americanradiohistory.com 767 March, I918 ELECTRICAL EXPERIMENTER without being rebuilt to suit the high A RADIOPHONE. A GOOD SUBSTITUTE FOR A SECRET power. This idea was original with me, SI,F.FRE1 BROS. PRACTISE BUZZER. By and I hope it will benefit other amateur article is to show how The drawing shows the hook -up of the The object of this radio men as much as it has myself. and still not in- apparatus. The source of current is the one can use a Radiophone not be used on A. C., The voice 110 volt D. C. power mains. The "Trans- This device should terfere with the radio -telegraph. but on D. C. It pro- due to the is very clear, duces a note resembling fact that there are not "N A A" on the 100 any other disturbances K. W. spark set. The going on while talking. tone heard is duc to the The voice has a ghostly pulsatory nature of di- sound. This experiment rect current as pro- by us was carried on duced by a dynamo. for several years, and Contributed by has given very good re- PAUL G. WATSON. sults. It will usually only work in the day- AN IMPROVED time in cities, as the RADIOPHONE arclights on street cor- ARC GAP. ners interfere quite a Herewith is described bit at night. an improved arc gap Following is an out- for use in radio -phone line of the talking and work. The carbons Aerial, B =B attery, G= Ground, hearing instruments: n the Above Diagram of Radiophone HookUp A= ordinary of Spark Coll, and R =Telep hone Receivers. are of the 1. The larger the an- P= Primary and S=-Secondary hard variety that can tenna, ground, coil, and (if it could be called ouch, con- be found in most any dry cells. The ad- source of current, the greater the distance. former" in each a 1" coil having its vibrator vantage of having grooves sawed 2. The higher the resistance in the re- sists of spark of wire) connected in end of the carbons is that it keeps the ceidcrs the better it is. shunted with a piece a bank of 16 C. P. 110 volt arc from running along the edge to the end 3. Long distance transmitter (micro- series with are in parallel. The key is an and burning the mica sheets. The mica phone) is preferred. lamps, which key and the 'phones are sheets can be obtained from old fuses. The 4. Dry batteries are all right, but would ordinary telegraph regular, high resistance 'phones used in rubber bands are placed around the carbons prefer a storage battery for larger coils. th'e them radio work. to hold them in place and still keep The volume of the sound can be varied in insulated. GOOD BEARINGS FOR. ROTARY two ways. The more lights in parallel the GAPS. louder the sound, or if it is impossible to number of lights and the core rotary gaps are to be mounted diminish the When spark coil is accessible, its removal separately from the motor shaft the ques- of the or partial removal will cause a smaller volume of sound in the phones. This nethod of substituting a power current for that of a buzzer has several advantages over

S Cp !ompbo/M-

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l/OeDC .MD OSC// C a7 Coi/ ey SDc' ó zc Unique Hook-Up For Learning the Code By Connecting Spark Coll to 110 Volt D. C. Circuit. (11111121121111111

Photograph of Finished Bearing For Rotary other methods utilizing the light current as OM. , i Spark Gap. a source. First, it does not click when the key is deprest as most of the other methods oal tion of obtaining suitable bearings must do. Second, an Omnigraph or other form ANN. be considered. 1 have devised a simple of automatic transmitter can be used with it bearing which does not necessitate the e^d making of a pattern and casting, which process is usually expensive. fitted into a threaded hole. In turning holes Obtain full two inches of 1 -inch square out the bearing be sure and drill the Hook -Up and Detail of Novel Carbon Arc brass rod and saw off the piece into two hru the sides of the rod which were man - Gap For Radiophone Experimenting. equal parts. These rods must be exactly ifactured square, otherwise the hearing one inch square. Center them in a lathe will not be true, since it is impossible to The color of the arc should be of a blue - chuck separately, and drill the hole desired. purple to give a smooth tone. A white glare After taking from the chuck it is necessary is not good as it shows the carbons are to ream out the hole. Drill a hole at the burning. The carbons must be at least top of each bearing block and fit a small 1/32" apart to obtain the best results. In oil cup into same. This cup should have a this wav the voice will be clear and strong. piece of felt fitted into it to keep the oil while the arc will he very faint. We find from running out too easily. Obtain two that it is better to have the carbons placed sheets of brass 2 "x21/2"x%" each, and drill side by side instead of end to end, as it a bole in the corner of each for screw keeps the arc running hack and forth on the fastenings. smooth round side of the carbons. and keeps The bearing is complete after the brass them cool. Otherwise by having the arc sheet is soldered onto the bearing block. at the ends of the carbons, it stays in one Do not solder around the bearing block place and tends to heat up and burn the but apply the heat directly to the sheeting carbons. and apply the solder between the bearing We have experimented with this radio- hlock and the sheeting. If the lathe work phone for three years and have succeeded is done accurately the bearings will match in talking thirtv miles distant. exactly. Working Drawing of Rotary Spark Gap Bear Contributed by SEEFRED BROS. A necessity for each bearing is a moving, Fitted With Oli Cup. held against the block on the able collar accurate. The Now is the time to study up thoroly shaft. This collar can he made by turning file a brass surface absolutely drawings show the general on Radio and Electricity! You will find out on the lathe from 1" round brass stock accompanying the bearings and collars. hundreds 'of valuable articles in back wide. Into this. is drilled a hole the design of %" by F. MAC MURPHY. numbers of the "Electrical Experimenter.' size of the shaft. A small set screw is Contributed

www.americanradiohistory.com 768 ELECTRICAL EXPERIMENTER March, 1918 THE 2N5TRUQTR I_ --J I 7 t J ( 3 l ) 1 .1 E 1 i 1 =L._C j l Ji

Electro -Static Experiments By FREDERICK VON LiCHTENON' PART I THE attractive and repulsive forces the "Electro" imshurst type is required oppositely charged. as quickly released peculiar to Static Electricity enable for the successful reproduction of the fol- under the neutralizing spark. attracted again the person experimenting in this lowing experiments. which will help the under the new charge and so on. which. 'field to perform "stunts" which he novice in grasping the principles underly - assisted by the springy element existing in could not possibly produce with the ing them. it. will cause it to vibrate at an incredible speed. aid of any other kind of electricity. How- Experiment . \-o. 1 -( "Opposing" chains). Here is a simple and yet quite pronounced way of showing the repulsive effect on like charged bodies. Two very re2 4.'72 e -e light and equally long brass chains. such as y are usually found around static instruments -v ,, e! for connection purposes, are suspended side - P. -- _ _r ____. by side by their respective ends as shown in Fig. 1. They must hang \veil off the table ^.

www.americanradiohistory.com March. I918 ELECTRICAL EXPERIMENTER 769

ing spark, they fall back into their former is placed another nut (F) with its corners difficult experiment to construct a card - positions only to be attracted to one an- pointing midway between the nuts on the compass c,pecially designed for spinning. other again with the approach of the new circumference. A copper brush (E) is \lake the magnetic bar rather thin, al.o charge (Fig. S). This in repetition causes placed near enough to I F) that the points beveled and rounded as shown to reduce a sort of swinging motion on the part of will force it back a short ditance. This will air resistance. Attach it on top of the card. the tubes, which in the end- one would make contact with the point (C). The (it is underneath in the dory- compass) and standards (U) are then put on and con- drill a hole nearly thru from below to form nections made as in the diagram. The the socket for the pivot. The pivot may action is as follows: When one of the points of I F) push back the brush it doses the circuit and makes (A) a magnet; (A) then turns the rotor by pulling on the iron nuts. The circuit is opened just before each nut reaches the magnet. The momentum of the rotor brings the next nut in position. It the motor does not start at once spin the armature with the finger. Contributed by CLIFFORD BROWN. AN EXPERIMENT IN MR. MACE'S MAGNETIC CURRENTS. By Thomas Reed. The very interesting articles by Mr. Mace oil " \lagnetic Currents" calls to mind, and I believe explains. a phenomenon well known to skippers of small boats, which has never been satisfactorily. accounted for. I refer to the "spinning" of a card -compass. Interesting Experiment with Compass -card The "dory compass." so called. is corn- and Needle, Which, Under Certain Condl The Swinging Geissler Tubes -a Beautiful tlons, Will Spin for Long Periods. and Striking Experiment. Every Time the posed of a magnetic bar attached to a cir- Tubes Approach, a Spark Jumps Between cular card imprinted with the compass - be a line steel sewing- needle. The card. Them, Lighting Them Up Momentarily. points. The card, of course, turns with of thin bristol -board (say 5" diameter). They Then Fly Apart, the Action Repeating should be as perfectly circular and fiat as itself as Long as the Static Machine is the magnet, and the points are read off Worked. against an upright line inside the case, possible. in operation, it should be covered called the "I» bberline." with a bell -glass to shield it from air -cur- think at least -must lead to their striking Now very often, as the bolt thrashes rents; better still, place it in the partial hard together; but they never do. Every about in a choppy sea, the card begins to vacuum of an air -pump. time they meet, the resulting spark acts spin. It takes on a rapid rotary motion as if it were a cushion placed between of something like 200 R.P.\l. in its hori- AN EASILY MADE ELECTRIC them : in fact. they sometimes seem to zontal plane, and keeps it up indefinitely. SOLDERING IRON. cling together for the instant, while the I say "indefinitely," because 1 have seen Any experimenter owning a small 110 -volt is which on the discharge taking place, it go for minutes at a stretch; but as it is step -down transformer, having a secondary forces them always a fresh other hand to a great annoyance to the skipper, depriving voltage of 15 20 volts, will find the solder- start, in this way limiting the momentum him of the use of the compass for the ing iron here described very useful. \'her: They \ gained by the tubes on each trip. time being, he always stops it as soon as once heated it remains at an even tempera- in manner as long as the will perform this convenient, by canting the compass case ture until the current is turned off. To machine is in action, the terminals of (which normally is kept level by gimbals) make it. first procure a small soldering beyond which are to be separated their till the card drags on the bttom, and the copper. of about the size shown. \\'rap spark limit. rotary motion is destroyed by friction. two layers of thin mica around it, and On these static I working out "stunts" In the better class of compasses, the case fasten temporarily with a string. The mind beginner, but the had in not onh' the is filled with a transparent liquid (alcohol winding should be of No. 22 or No. 24 less capitalized experimenter who, unable or oil) in which the card and its magnet German silver resistance wire, the length expensive ap- to buy the more auxiliary are immersed. preventing the spinning. of which is best determined by experiment paratus. may not be satisfied with the aver- A plain compass -needle, without a card, Start the winding about ,A" from one end. age run of experiments belonging in the will not spin. The card seems to act as leaving the lead several inches long, and tissue paper -tinfoil- pithhall class. a fly -wheel, carrying the needle past some spacing the turns about 1/16 ". (To be continued) sort of dead centre. When as much wire a. possible is put on. The spinning seems to be initiated by cover with a laver 01 mica and wind a SIMPLE BATTERY MOTOR. a succession of "yaws" as the boat is swung similar layer of t r this. Fasten the end H:rewith I give a diagram and descrip off her course by cross -seas. These cause securely, and bring out ;:..)ther lead. The tion of a small battery motor. This motor a wide oscillation of the needle; and once whole winding is new covered with several. is quite simple and is easily constructed, these are wide enough, the fly -wheel action layers of thin sheet asbestos. and a layer besides being very powerful for its size. comes into play, and the card starts spin- of fine copper or iron wire is wound tightly It can be made in any size, but the small ning. I have never seen it stop of its own over this to protect the inner coils. sizes give the most satisfaction. The mag- accord, and I believe it would go on until The leads are covered with asbestos for net (A) is made by fitting a machine bolt stopt by friction developing at the pivot. several inches and are then soldered to a i4" long thru the 3" upright (.H) and In short, I believe that here we have a flexible cord which passes thru a hole in winding the bolt with No. 26 insulated mag- case of perpetual motion- except, of course, the handle. 'if difficulty is encountered in net wire. The rotor (B) is a cylinder of for friction, which would eventually make winding the/German silver wire, due to its wood, PA" in diameter and %" thick. On the pivot stick. This is a bold statement, springiness,lit should first be annealed by because the possibility of perpetual motion is denied. But this is not per- Asbeslos Cord Leads o.'ac!ive.Y,ndrs petual motion in the So/der Asbes/os old sense of a force mico acting against itself : we are merely utilizing an earth -force to produce an effect, exactly as a wind- mill utilizes the wind. A reference to the Construction of Home-made Electric Soldering iron. It Can Be Made Simple Form of Battery Motor of Interest to from a Copper Tip and Handle, as the Drawing Shows. the Young Experimenter. diagram will show Standard how I imacint 'he its circumference and at equal distances result to he brought about, in accordance passing a current thru it u;:til heated to are placed four iron nuts (G). These can with Mr Mace's theory. In our latitudes. a dull red. If the iron becomes too hot be screwed on with flatheaded iron screws. the earth's magnetic axis is very appreci- in use, the current should be limited by an The shaft can be made of any durable ahly inclined. which would seem to aid the external resistance, consisting of several metal, as it has no electrical function to effect, and perhaps wholly account for it. coils of No. 20 German silver or iron wire. perform. On the shaft, close to the rotor, It would he a very interesting and not Contributed by AN EXPERIMENTER.

www.americanradiohistory.com 770 ELECTRICAL EXPERIMENTER March, 1918 A Speedometer for Small Battery Motors By STANTON C. MOORE N easily constructed speed indicator, or stock, about 4" x 7 ". The motor, A, is somewhat to do this, but that can be easily more properly speaking, a speedom- fastened at one end with the shaft set trued up again. Now heat the nail about eter, for battery motors, that can exactly parallel with the center of the base. half of its length and flatten it out. File it a hack saw A be made from the odds and ends Part B is made of hard, close -grained smooth on both sides and with that are usually found in the ever - wood (such as mahogany), 1" in its larger make a slot the length of the flat part. useful scrap -box, will no doubt commend diameter and %" thick, with a hole bored The arms, D, may be made of iron, if itself to the "Bugs" who, being debarred thru the center to fit very tightly and your junk -box refuses to yield brass, about 1/32" thick and 2" long. Width at one end 3/16 ", tapering to s" at the other. File them up neatly and drill a hole 3/32" from the large end of each, large enough to take No. 2 three -eighth inch, round - headed, brass wood screws. For the weights, C, cut from a piece of sheet lead, about 1A" thick, two pieces /z"'' x 1" and fold them in the middle. Drill a hole in the small ends of the arms and slip the folded pieces of lead down over them. Hammer the folds together and you have two arms with a lead weight on the small end of each, the lead sinking into the holes in the arms, thus fastening the weights securely. To make a neat job file the corners off and smooth up. Five- eighths of an inch from the large end, near the edge, drill a small hole, g, Fig. 3, thru which to thread the cord, G. These arms are fastened at their large end as shown in the drawing, with a No. 2, three -eighths inch, round -headed, brass wood screw ; a washer being placed between the 'trm and B to minimize friction. The center of the screw should be Here Is a Neatly Worked Out Direct -Reading Speed Indicator For Use in Testing Small Battery Motors or For Giving a Steady Indication of t he Speed, Where Thls Is Essential. It Can Be %" from the circumference of B Calibrated to Read R.P.M. if Desired. and 3/16" from a line drawn thru the center of the two guides, H. from uiing their radio sets, are engaged accurately on the projecting shaft of the A small staple, F, made of round wire in Electrical Experimenting. motor. This hole must be bored exactly at is now driven into B so that it spans the While working with a certain device I had right angles with the face of the part so that motor shaft. (I say round wire staples occasion to make and break a circuit at when mounted on the shaft it will run advisedly, because if you use the square certain intervals and also be able at will to absolutely true. It must be noted that in this wire kind such as is employed in tacking alter the intervals and jump to any one of device the slightest movement in any of the down floor matting and linoleum, the sharp four different degrees of rapidity. I tried parts is communicated to the pointer and edges will cut the cord which we are to an electric clock, but in order to change the multiplied about ten times. For this reason thread thru it.) Drive it in all but about period of make and break it was necessary the utmost care must be taken to make every 1/16 ". to stop the pendulum to slide the bolts up or part as accurately as possible.- Otherwise Take a short piece of stout cord, some down the rod. This was fatal to the device the vibration will cause the pointer to wob- thing on the order of a good quality fish I was working with, so after trying various ble to such an extent that even an approxi- other schemes. I adopted a modified form of mate reading will be impossible. commutator driven by a toy motor. By Parallel to the shaft hole, 3/16" from it, varying the speed of the motor with a rheo- bore two holes just a trifle smaller than the stat the periodicity could be changed with guides, H. These guides are made from ease. However, I found that to get any one six -penny finishing nails but 1%" long and of the four degrees of speed that I required, forced tightly into the holes just bored on it was necessary to use the "cut- and -try" either side of the shaft hole. They should method of putting in or cutting out resist- be in perfect alignment with each other and ance until the proper speed was secured. with the shaft. This was even worse than the clock On these guides is fitted the slider J. This arrangement had been, but the logical thing is made in the form of a flat -bottomed "U" to do in this contingency was to devise a of brass, preferably, or iron about 1/32" method of determining quickly and with thick and about 3/16" wide, with holes certainly just when the right motor speed drilled in each leg to take the guides H. It for the desired periodicity had been ob- should slide smoothly on the guides but tained. Hence the speedometer here de- without too much play. A hole is drilled scribed. in one leg to take the link, I. This hole The drawings are presented mainly to should be exactly midway between the holes give a general idea of the principle and the for the guides so that the centre of I coin- relative proportion of the different parts cides with the center of the shaft of the rather than exact dimensions, as these de- motor. A very, small hole should also be pend largely upon the size and power of the drilled in the center of the opposite leg to motor on which you wish to use the device. take the cord. G. However, as it might be of assistance in To make the link, I, cut a six -penny fin- determining what size to make the various ishing nail about 1%" long. File the under parts to suit your conditions, 1 give in the side of the head square with the shank and Detall of the Direct -Reading Speed Indicator following directions, the dimensions of the make it as smooth as possible as this joint Fly -Ball Governor Mechanism and Needle speedometer which 1 ám using on an "Ajax" is where most of the friction comes, and Actuating Means. motor. These, of course, are arbitrary and this of course, should he reduced to a mini- may he varied to suit conditions and the mum. The top of the head may he ing line, and put one end thru the small material which you are able to dig out of rounded as shown for the sake of appear- hole in the back of J. Tie the end into a the "scrap -box." ances. Insert this in the hole drilled in J to good sized knot so that it will not slip The base is made of half -inch mahogany receive it. You will have to bend the slider (Continued on page 805)

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 771 My Electrical Laboratory By WALTER BOCK (Special prize $5.00)* HEREWITH are six photos of my chemical reagents. The things that look of at least 15,000 meters so it is said. shop and Electrical 'Lab" includ- like the noses of some "one- pounders" are The contractor must guarantee transmis- ing myself -one "Stript for action" the tops of my file handles. sion from the French station to the Ameri- and the others -"all drest up and Last hut not least comes my bench with can station (on any day of the year) of nowhere to go." The photos more than 300 wood and metal working 10,000 words per 24 hours. :Moreover, the show most of my electrical apparatus. tools such as twist drills, hand drill, drill transmitting and receiving apparatus will All told I have approximately 50 pieces of press, adjustable tool grinder, and so forth. be adjusted in such a manner as to allow of the same, such as spark coils, Tesla and To the left is my 30 drawer stock cabinet, continuous transmission and reception at Oudin coils, Leyden jars, glass plate con- containing machine and wood screws, nails, the minimum speed of 4,000 words per hour. densers, magnetos, dynamos, motors, volt- bolts, nuts, springs, contacts, binding posts, Adjustments permitting musical transmis- meters, ammeters, polarity indicators, paper ad infinitum. sion and auditory reception at the speed of condensers from .0165 to 1 mf., rheostats, 50 words per minute are also provided for. fixt and variable inductances, Geissler tubes. 'See announcement in Feb. 1918 issue, Transmission by the French station of storage batteries, interrupter, etc. page 701, wherein we asked far special signals destined for reception in the United

The Author "on the Job" In His Laboratory.

The Electro-cheml- cal Branch of This Some more of the Vpto -date A m a - Chemical "Lab." The Electr,cal Bench, Contam- t e u r' s "Electrical Equipment. Each ,,111I1'1'1{111',111, Ing Tesla High- frequency Coll, Laboratory." Several Chemical Is Care- Spark Coils, Storage Batteries, Special Apparatus fully Labeled and In Leyden Jars, Et Cetera. Are Available. Its Place.

Owing to the fact that space is limited, article, with several photos describing your States of America, and the reception by the (my shop measures 12 feet by 14 feet), I "Electrical Laboratory." Tell us in not French station of signals from the United have to put away all apparatus that I am more than 500 words what you do in your States, simultaneously and independently, thru using to make room for another "Lab," Blake your article interesting and will be correctly and efficiently carried out. experiment. Therefore I have no fixt elec- be sure the photographs are good and clear. trical "Lab." The table of my chemical Address the Editor. "Lab" seriiing the double purpose. One CAMP MEADE PICKS UP RADIOS photo shows the "Lab" table with twenty - FROM NAUEN. five of my forty or so pieces of chemical RADIO COMMUNICATION BE- Camp Meade's wireless operator (at Bal- apparatus, such as thistle tubes, test tubes, TWEEN FRANCE AND THE timore, 1\Id.), Jim McGarrity, caused a delivery tubes, retort, Erlenmeyer, and UNITED STATES. tremor of excitement recently when he an- Florence flasks, chemical balance, c.c. grad- A radiotelegraph station destined to estab- nounced that he had just picked up several uate, mortar and pestle, etc. lish direct radiotelegraphic communication messages from the great wireless station at To the right of my "them. lab" is one of between France and the United States of Nauen, Germany. The messages were all my book cases containing some fifty elec- America will shortly be establisht by the in the official German code, and therefore trical, chemical, and mechanical books - French Government. It will be situated could not be deciphered by anyone here. among others -three volumes, of the on the \Vest Coast of France and will main- The headquarters officers would not believe ELECTRICAL EXPERIMENTER (I have them all tain permanent and continuous radio -com- lim at first the distance to Nauen being 4,000 miles. He silenced them as far back as April, 1915) ; the Model munication by day and by night between more than Library series and Henly's Formulas. An- France and the United States. It will ra- by displaying the messages, which were im- other photo shows some of my 140 odd diate continuous waves with a wave -length mediatel forwarded to Washington.

www.americanradiohistory.com 772 ELECTRICAL EXPERIMENTER March, 1918

How to Make a "Blinker Light" for Motor Boats Important Notice to Subscribers Every small sailing or engine- driven bored four holes of % -inch diameter in the water craft should be equipt with an ef- bottom, and put the arrangement together Due to the congestion existing at the ficient "blinker light" for signaling to with two thin 2g -inch brass screws, I had present time in all railroad movements, my lamp. Of the also on account of the fact that many train four % -inch holes clerks have gone to war, there is a con- on the bottom, two gestion of mails all over the United States. 1 U are used for the It may happen that your magazine will be fastening screws slow in reaching you, and this delay may and two for ven- be from a few days up to several weeks. l'giumm=k21 tilation. l did not Kindly bear this in mind before sending insert the glass in in a complaint, as the magazine will surely the bottom piece of reach you in due time. Only after not mahogany until the having received a certain copy for a varnish was dry, period of three weeks should a complaint as this piece should be sent in. be easily remov- You will confer a favor upon the able for replacing publishers not to write until this time bas the bulb or clean- elapsed, thereby saving them a vast ing the glass. amount of clerical labor. When it came to fastening the light, HOW TO GET A PORCELAIN I wanted it to set KNOB FOR RHEOSTAT.. a little ahead of I was recently in need of a knob for a the mast and above rheostat and thought I would try an old it, so that it would porcelain door -knob which was not in use. not interfere with To construct this knob first procure a porce- the halyards, etc. lain door -knob with a set -screw in it. Next I therefore took a take an old buggy bolt and cut the head off piece of waste and as much of the bolt as desired. As brass 1/16 inch in Fig. 2, file one end square so as to fit thick, 6 inches in the door -knob and leave the other end long by 14/4 inches threaded for the lock nut. Procure a piece wide, bent it to L of brass and cut it into the shape shown a brack- shape for in Fig. 3, which is 31/4" long and 3" wide et and bored holes at the larger end, with a square hole in it in it to correspond to fit on Fig. 2. in the square shank, In Fig. with the holes 4, "B" represents the switchboard and "D" - the bottom mahog- is a copper strip with a hole in the center Ef any piece. In using A copper wire can be soldered on this 4.77 the long fastening pr copper strip for connection. In Fig. 1 screws mentioned "CC" are washers and "B" is the switch- the Small Motor above, I put them board. I have been using this for Here's a Simple and Effective "Blinker Light" For brass. some Boat and Launch. It Can Be Operated From a Few Dry Cells or first thru the time, and it is giving good results. Storage Battery, the Telegraph Key Enabling Messages to Be Signaled (The illustration Contributed by in the Morse Code. shows the brass be- CLIFFORD LUNDQUIST. fore being bent and other craft or to shore. Such a blinker without the screw holes for fastening it light is described by H. A. Jackson in to the mast.) The other two small holes Motor Boating. correspond with the ventilating holes and the This simply made lamp can be used with the large hole allows the lower end of is to be per- weather -proof fixture and the wires to pro- equal facility whether it use lamp manently fixt at the mast -head (which is ject thru. If it is desired to this much the better way) or hoisted on the on a halliard, omit the bracket and provide yardarm halliard whenever wanted. a screw -eye for the top piece of ma- Keeping in mind that the lamp should hogany. not be too large, must be seen all around The rest of the outfit consists of a send- the horizon, and should be neat in appearing key, dry or storage battery, and wires ance, I first tried to buy a plain glass tube to connect. The sending key can be an or- of about 2 -inch inside diameter and equal dinary push button, or a regular tele- length-but found it impossible to obtain. grapher's key. The latter is about twice A friend then suggested the kind of glass as expensive as the push button, costing that is used in oil cups, and my troubles in the neighborhood of $1. But it is much were ended, for I was able to get a glass more satisfactory and the light can be of A -inch wall thickness (heavy enough made to burn steadily (and so used for an to withstand any usage), 2g -inch outside anchor light) by pushing in the right hand Fi9.l diameter, and 2A -inch length, at a cost of arm (see illustration). (A good glass cylinder but as the twenty -five cents. The wiring is also very simple, fl , would be one such as supplied on certain wire is to be used for outside purposes, it Fig2I radio receiving condensers.) should be well insulated. If attached to From the waste pile in the boat yard I the mast and painted with a couple of then picked a 3 -inch square piece of ma- coats of yellow paint, it will not be noticed hogany which was awaiting consignment and the paint will help the insulation. Con- to the stove, and with a lathe rounded off nect the two wires to those projecting Fiq.3 the top neatly and cut a groove in the lower from the bottom of the weather -proof fix- side 3 -inch in width and depth and of a ture, leading one wire directly to the stor- diameter equal to that of the glass. I then age battery (or if you have no storage gave it three coats of spar varnish, and battery to one dry cell), and the other to while the last coat was wet, inserted the the left binding post on the sending key; glass and let it dry. I then had the top also run a wire from the right binding post D and sides of my lamp. For the bottom, I to the dry cell or storage battery. Then, 1131102Q piece of wood, left it by pressing down the key, you will light i.. selected a similar e flat on top and bottom, and on the top cut the light, and by releasing it will cause the a similar groove to receive the bottom of light to go out. A 2 c.p. bulb will be amply Fig.4 Q the glass oil -cup tube. The center of this sufficient, and the voltage of this bulb bottom piece has a hole bored to 3d -inch should, of course, correspond with the such a "blin- diameter for taking a weather -proof tube amount of power used. With f You Have a Porcelain Door Knob At socket like those used to decorate large ker light" equipment, communication can Hand Here's a Good Use For It -as a Rheo- Christmas trees outdoors. Having also he carried on at considerable distances. stat Control Knob.

www.americanradiohistory.com March. I918 ELECTRICAL EXPERIMENTER 773 Siphons -How They Work By I. W. RUSSELL and J. L. CLIFFORD

con- flask is ASIPHON is an instrument for there a valve controlled opening. right spirit, consists in putting a series of veying liquid from one vessel to an- By stopping up the longer arm and apply- questions to nature. The result of the ex- other at a lower level and is usually ing suction to the upper aperture, the periment constitutes nature's answer. and in the form of a bent tube. The word itself siphon is started. The valve is then closed when this is correctly interpreted our comes from the Latin word "siplio," mean- and the siphon will then act the same as knowledge of the universe in which we live ing tube. The principle of siphons has type 6. For safely and easily handling and of which we form one tiny part be- probably been known for centuries; even acids the siphon shown in Fig. 2 has been comes more complete. Now if experiments the ancients were acquainted with the sim- pronounced by Prof. C. D. Dilts, an au- are to.lead to fresh knowledge they must plest forms of this interesting apparatus. thority on siphons, to hold the greatest pos- be performed methodically. So far as the Altho the siphon enjoys the greatest use sihilities. \ \'hen the siphon is inserted into confirmatory experiments suggested in text- in laboratories, for the purpose of handling a bottle of acid the liquid rises into the books are concerned, the conditions are ex- acids. it has a great many other applica- tube. By blowing in the small tube, the plained by the.author of the book, and the tions. Innumerable forms have been de- valve at the bottom is closed and the acid experimenter has little to do beyond carry- vised and adapted to all purposes. Pipes is forced out of the siphon tube. With ing out the instructions as carefully as pos- used for conveying the water of an aque- this arrangement there is absolutely no sible. But original experiments need to be duct over hills and following the contour of the sides are often called siphons, but do not necessarily depend for operation upon the principle of the instrument defined above. The simplest form of siphon as illustrated in Fig. I, consists primarily of a bent glass tube with arms of unequal lengths. In starting this siphon the tube must either be filled with water previous to inserting it in the vessel or, after being placed in the vessel a suction applied to the lower arm. To explain this flow of water from the siphon. let us suppose it to be filled by either method described above and immersed in the liquid. The pressure then at the end of the shorter arm tending to raise the liquid in the tube, is the atmospheric pressure less the height of the liquid in the shorter arm. In the same wav the pressure at the end of the longer am is the weight of the atmosphere minus the pressure of the column of water in the longer arm. Since the column of water in the longer arm is longer than that in the shorter arm, the force acting at the end of the shorter tube is less than that of the longer ; consequently a flow of water takes place proportional to the difference between these forces. The flow will therefore be more rapid in proportion to the difference of level between the end of the longer arm and the level of water in the vessel. In Fig. 4 is shown a type somewhat similar to the first. It consists essentially of a bent tube with arms of equa] length. Besides the methods outlined in connection with the first system, this siphon may be started by plunging quickly into a vessel filled to the brim with water. The siphon must be handled skilfully in order not to break the tube and cause the column of water to he forced over the ridge in the tube. Another method is to stop one end with the thumb and inserting the free end A Study in Siphons. These Clever Mechanical Devices Are of Interest to Every Electrlca into a vessel filled to the brim with water. Experimenter For the Purpose of Transferring Acids, Electrolyte From Carboy to Gel Upon removing the thumb, the water rises or Vice Versa, and Other Work. in the tube and is carried over the ridge by its surplus momentum. danger of drawing acid into the mouth. well thought out beforehand. and when this A commercial form of siphon intended A siphon of great scientific interest but of is done it remains to arrange the manipu- for transferring acids from one vessel to small commercial value is what is known lative details with a view to getting a clear- another is shown in Fig. 5. The principle as the automatic siphon illustrated in Fig. 3. ly defined result, unaffected. as far as pos- is nearly the same as the first with ex- The tubes are arranged as shown in the sible, by disturbing causes. ception that the siphon is started by apply- drawing. When this siphon is inserted in a Contributed by H. J. CRAY. ing suction at the exterior arm. With vessel containing water, the tvater rushes this siphon, however, there is danger of in at the lower aperture and causes a pres- --- some of the acid reaching the mouth. In sure in the larger tube, which causes the Fig. 6 is shown what is known as the water coming up in the lower tube to be AUTHORS!!! siphon fountain. A flask is partially filled forced up into the siphon tube, thus creat- All matter intended for publica- with water and glass tubes are arranged as ing a flow. There are many types of siphon; tion -not only by us, but by any shown in the figure. Upon inverting and with other than those shown here which are be- the shorter arm immersed in the liquid of yond the limits of this article to describe. other magazine or newspaper as some vessel, a flow is occasioned. As the As this is an intensely interesting subject. well -should be written on one side water is drawn out by way of the longer the serious reader will be highly repaid for of the paper only and in ink. If it arm a vacuum is created in the flask, caus- ally labor exerted in experimenting along isn't, somebody else must ing the water to rush up the shorter tube, this line. copy part thus forming a fountain. of it off on another sheet before it A commercial form employing this idea METHOD IN EXPERIMENTING. is given to the printer. is shown in Fig. 7. At the top of the Experimental work, undertaken in the

www.americanradiohistory.com 774 ELECTRICAL EXPERIMENTER March, 1918

A SPECIAL GOLD -LEAF ELECTRO- tremely delicate. The piece of gold leaf After these short explanations the con- SCOPE FOR RADIO -ACTIVE about an inch long by 3' wide is attached jurer passes the bettle to the audience for EXPERIMENTS. to the brass strip by a tiny drop of shellac. examination to show that there are no THERE have appeared lately in this It is possible with this electroscope to see threads or similar devices hidden anywhere. magazine several articles on Radium the gold leaf and the strip on the scale be- He also shows that the glass plate is not and Radio -Activity. In these articles hind and notice the position before and prepared in any way, and the plate may also the experiment of discharging a gold -leaf after charging. be past on to the audience for examination. To use this electroscope charge with a After this, the performer puts the plate glass or hard rubber rod excited with silk back into its former position, and passes or catskin, and notice the position of the a stick, which he borrows from the gold leaf on the scale. Leave for about audience, between the back of the plate and fifteen minutes, and if the conditions are fa- the curtain E, which is about 6 inches vorable, and the electroscope well made, the behind plate A. He now places the beetle leaf will be in the same position as before. on square No. 1 and the beetle will cling Take some Radio- Active substance (the to the plate. Members of the audience writer used Uranium nitrat and Uranyl are now requested to call out different chlorid) and put upon a grounded copper numbers and the beetle will slowly move to plate. Charge the electroscope and place the square bearing the specified numbers. over the plate and notice the position on the For instance, if the beetle rests on square scale of the gold leaf. After a few minutes No. 1, and No. 9 is called out, the beetle again notice the position of the leaf. The will move from 1 to 5 and from 5 to 9. electroscope will be discharged. The alpha If the beetle is asked to go back again to particles emitted by the Radio -Active sub- No. I, then it may take the following way: stance have ionized the air, permitting the 9 to 6, 6 to 3, 3 to 2, 2 to 1. This proves charge on the electroscope to leak away to that the beetle can move in any direction. the grounded copper plate. In this way it Small additions or multiplications are also is possible to measure the Radio- Activity of carried out by the ever obedient beetle. different substances by the rate of dis- After the performance the beetle and glass charge off the electroscope. The writer has plate are again past to the audience for also found that an E. I. Co.'s Spinthariscopc examination. with the lens removed, would discharge the The explanation of this trick is as electroscope. Radio- Active salts (such as follows: As mentioned before, behind the all Uranium or Uranyl compounds) can plate A at a distance of about 6 inches is Appearance of Finished Electroscope Espe- easily be secured at any chemical supply a curtain E. Fixt to the back of this cially Designed for Conducting Experiments house. curtain is a piece of cardboard F, the same In Radio- Activity. size as the plate A. This cardboard is also divided into nine equal spaces and the electroscope by some Radio- Active sub- position of the cardboard is exactly behind stance is mentioned. This is an intensely the plate A. The performer's assistant is interesting experiment, but the ordinary stationed behind the curtain, holding in his flask electroscope is not suitable for this ex- hand a powerful electromagnet G, which periment. With the usual electroscope is connected by means of wires H to a there is no convenient way of bringing the resistance J, and a few storage battery Radio- Active salt near the electroscope and cells K. As the assistant hears the leaving it for some time. Besides there is numbers called out by the audience he no way of measuring the collapse of the moves the magnet G to the number required. gold leaf, and the ordinary electroscope in The body of the beetle D contains soft the possession of the amateur will not hold iron wire and the powerful magnet G its charge sufficiently well. Because of these attracts the beetle and supports it in this difficulties I constructed a special gold manner. The body of the beetle should be leaf electroscope, which, under ordinary as light as possible, and the beetle when conditions, will hold its charge several hours completed may be about one inch long. and which lends itself especially well for Thin iron wire should be used to form the experimenting with Radio -Activity. body and when finished, the beetle should As may be seen in the photograph, the be painted a bright golden color. To make electroscope is housed in a rectangular box the trick more effective, the room may be of %" quarter -sawed oak. The box is 3" darkened and the light of a 50- candlepower square at the top and about 5" high. There lamp may be directed onto the glass plate A. is no bottom to the casing, and in the front This would show the gold color of the there is a glass window to permit the ob- Details of Electroscope For Radio- Active beetle more brilliantly and the beetle will to watch the collapse of the gold leaf. Experiments. It Employs a Single Gold look almost life -like when moving. server Leaf as Shown, the Movement of Which IS Directly in the rear of the box there is an Measured on a Transparent Scale. opening about the size of the front window. Over this opening a piece of semi- trans- parent paper is glued, on which a scale This electroscope besides being useful for is drawn as in Fig. 1. This should be put experiments with Radio -Active substances on after the rest is finished so that the scale is a valuable asset to any experimenter's may coincide with the gold leaf. laboratory. The construction of the top of the box is Contributed by JAMES L. CLIFFORD. illustrated in Fig 2. A piece of fairly thin brass or phosphor bronze strip about 3%" THE MYSTERIOUS BEETLE. long and 3A" wide is smoothed well. Any By. C. A. Oldroyd. slight cut or jagged edge is apt to cause This illusion is worked by electricity, leakage. This strip is bent at right angles and will never fail to keep the audience half an inch from the top, and put thru an spellbound. The effect is as follows: inch hole cut in the center of the top. The The performer shows a glass plate about top of the bend in the strip should be even one foot square which is suspended from with the surface of the wood and should two silk cords B (see sketch), which in not touch the wood at all. The hole should turn join the ring that is supported by the then be filled with melted sulfur. Be sure cord C. The glass plate A is divided into to heat the sulfur gently, and do not allow nine squares, each of which contains a it to burn as this destroys its insulating figure starting, of course, with No. 1. qualities. When the sulfur is hard sand- These figures and the division lines of the paper the top so that it is possible to see the squares are painted with black varnish. The top of the strip. The top is put on with performer shows a "beetle" which, so he thumb screws to facilitate removing and explains, he received from an Indian con- putting on the gold leaf. jurer. The beetle will cling to the glass Gold leaf can be purchased either at a plate without having any visible support, or a paint and varnish store. and will also occupy the squares of the The Mysterious Beetle Is Not So Mysterlou sign painter's After All -For He Is Moved From Square to It would be best to find out when you buy glass plate A, whose numbers are called Square By Means of the Electro- Magnet In it, how to handle gold leaf, since it is ex- out by members of the audience. the Manner Apparent.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 775

OPENING A LAMP CIRCUIT WITH A PISTOL. An Automatic Electric Railway The effect caused by this hook -up is as A simple way to run a miniature cable ing on the position of the motor field wires. railway mechanically and electrically is When motor runs in follows : An incandescent lamp bulb direction shown in is mounted on a cigar box which also has on it two upright wires, and a small wire connecting them (about No. 36). The uprights and the lamp arc connected in series, and they are connected by a lead wire and /lake Rreo-G.^'-' plug to a lamp socket. The current is turned on, and then the operator walks away some distance, produces a pistol, fires ( ?) at the wire, cutting it ( ?), when, £/ec/r,c Presto! the light goes out! \ A/o/or The way this effect is produced is shown by the diagrams herewith. In diagram 1, the current from the ordinary 110 -volt lighting circuit passes thru a switch, a fuse, a fine wire inside of a bottle containing hydrogen and air, an electromagnet, a strap Yor,ob/e Res,s/o,ce key or push button, another fuse, and the Ptieos/o/ other blade of the switch. The switch used Armature Leads is a D. P. S. T. with a fuse block. The F bottle will be described later, and the electromagnet consists of about 10 or 15 feet of No. 18 B. & S. gage bell wire wound on a % -inch diameter iron core about three inches long. The apparatus at Fig 3 is the cigar box with the lamp socket and wires mentioned above. The lamp socket is of the type with a hole in the center thru which a screw passes to hold it down. The screw used must be about an inch longer than is needed to pass thru the socket and box cover. On the lower part of this, below Re /ay Arma lure the nut fastening the socket down, is placed a brass nut with a brass lock nut under An Automatic Electric Railway That Electrical Experimenters Will Find Interesting. As it. In securing the socket make sure that the Moving Car Travels Back and Forth On Its Rails, It Trips Electric Contacts Which Serve the binding post connecting with the lead to Control a Relay Reverser Connected With the Driving Motor. from the lighting circuit is the one that shown in the diagram. The apparatus must diagram, the power of the car closes the comes from the center of the socket. The be operated by a series -wound motor for "make" contact, which in turn energizes uprights may be of iron wire and are bolted the connection scheme shown, its armature the relay coils. This causes relay armature down to the cover. The shove -bolt or being connected to the contacts on the relay to come forward and this action reverses screw for the one nearest the socket must armature. The field of the motor, thru a the direction of the motor. On the reversal be long enough to extend about an inch variable resistance, is connected to Nos. 1 of the car's motion, the "make" contact below the lower side of the cover of the and 2 contact screw; No. 1 screw being opens again, but current is not cut off from directly connected to No. 3 screw, while relay coils because No. 5 contact screw No. 2 contact is connected to No. 4 screw. being directly connected to battery, thence Fine Wire The "make" contact is connected directly thru "break" contact and relay coils, keeps in series with the relay coils. No. 5 contact them energized. The opening of the screw is directly connected to the battery, "break" contact by the car cuts off the cur- thence to "break" contact, to relay coils, rent from relay coils, releasing the relay and back to battery. The contact screws armature and bringing motor back to opposite each other are connected to op- original position. This action may be posite sides of the motor field. The forward repeated as many times as desired. The and backward motion of the relay armature variable resistance or rheostat contrgls the causes the motor to reverse when the relay speed of the motor. coils are energized, or vice versa, depend- Contributed by ARTHUR PRIEBE. box. After the nut to fasten it to the box pose. The insert shows a convenient stand cover has been put on, put on another one, to avoid "spilling" out the gas while //0Y 110V then a thin iron plate, and a nut on the generating it. bottom. Then we have the plate between Now that the apparatus is completed, two nuts which when tightened will hold the magnet must be hidden under the thing it. This plate must be long enough to on which the box is to be placed. I put it Llar just miss the bolt which comes thru the in my overcoat pocket on the bench by a BOX'" socket and as wide as the box, allowing hatrack and put the box on my overcoat enough room so that it can move freely The jar must be hidden near the place .5w,/ch without scratching against the sides of the where the gun is to be fired. and the strap box. Then the brass nut on the bolt key placed where the operator can touch it thru the socket is screwed up until it comes with his hand or foot Fly I within almost a paper thickness of touch- The operation is as follows: When the Bo ///e ,o/ it must not touch. key is closed, the current excites the magnet, Hydrogen ono' ing the plate. However, Then the other upright is put on. which pulls down the iron plate short - Air The method of collecting hydrogen is circuiting the lamp. This throws the full shown by Fig. 2. An ordinary iron pan is 110 -volt circuit on the fine wire which 4 - Fly 4 used, in which there is placed a salt solu- breaks as tho it had been severed by a tion and two lead electrodes. The nega- bullet. However, the resistance of the first tive electrode is put into the bottle which circuit is so low that there is a heavy rush is filled with the salt solution. \\lien the of current which fuses the wire at its current is turned on, by electrolytic decom- weakest point, which happens to be in the position, hydrogen goes into the bottle. The bottle. This fusing causes a spark which bottle should be filled about A full of gas. ignites the hydrogen and makes the noise It is then taken out, and a cork with two required to replace that which the gun wires bound to it having a fine wire con- would make if it were really fired. t Seems as it the Bullet Severs the Fine sisting of about two strands of No. 36. The two circuits may be on the same or Wire Next to the Lamp, Extinguishing it- B. & S. gage wire across them, is placed different lines, because they are only con- But Does it? This Trick Is an Excellent An olive bottle has nected by magnetism. One For Parties, Amateur Theatricals, Et in the neck. ordinary Cetera. it Will Puzzle Them All. been found very satisfactory for this pur- Contributed by GEORGE S. CARY.

www.americanradiohistory.com 776 ELECTRICAL EXPERIMENTER March, 1918

This department will award the following monthly prizes: First Prize. $3.00; Second Prize, $2.00; Third Prize, $1.00, The purpose of this department is to stimulate experimenters towards accomplishing new things with old apparatus or old material. and for the most useful, practical and Original Idea submitted to the Editors of this department, a monthly series of prizes will be awarded. For the best idea submitted a prize of $3.00 is awarded: for the second best idea a $2.00 prize, and for the third best prize of $1.00. The article need not be very elaborate, and rough sketches are sufficient. We will make the mechanical drawings. Use only one side of sheet. ]Lake sketches on separate sheets.

FIRST PRIZE, $3.00 SECOND PRIZE, $2.00 THIRD PRIZE, $1.00 LADIES! WATCH YOUR "SNAP LAMP "SOCKET" FROM A MAGNETIC PHONOGRAPH FASTENERS "! THEY MAKE GOOD SAFETY PIN. STOP. SWITCHES. I herewith submit my idea of an emer- I have found that by placing a pair of The experimenter who is continually rig - gency electric lamp socket. This socket ordinary electro- magnets, such as found in ging up different apparatus, will find that a may be quickly constructed from a safety few "snap fasteners" soldered to different pin of large size. It may be placed anywhere. The pin is fastened down by a tack or screw and is bent as shown in the sketch. The lamp is then screwed into the 131 ^s? e pin. Contributed by ELLS \NORTH EDGERTON. JnoO fo5leners 4ü1 t "as! Du /6 Ever Hear of an Electrical Use for "Snap Fasteners "? Well, Here we Have a ,cSd/ey Pin "Switch" Made from One. Watch Your Waists, Ladles! lengths of wire will come in handy for con- l necting them temporarily. The dome A Pair of Bell Magnets Mounted Alongside of the Record Table Was Found to fasteners can also be used as binding posts. Stop the Victrola Quickly. Contributed by S. BELL. - --Taca bells, buzzers, etc., along -side of the iron CHICKEN COOP ALARM. And the Safety Pin- Gaidarn it If it Don't table on my Victrola, that the record is Herewith is a drawing and explanation of Make a Good Hurry -up Lamp Socket. quickly brought to a stop when the current how I protected my chicken coop from is past thru the magnet coils. It is a simple thieves. By either opening the door or by matter to connect up the magnet circuit with pressing on the screen window, a buzzer YE GODS!! ANOTHER RAIN a special trip switch mounted on the tone would sound. The coop stands fully fifty ALARM. arm, so that the record table will be house, the incoming a stop as soon feet away from the and Herewith is a drawing of a simple electric brought to quickly as the wire is hidden under a fence. It works rain alarm. It needs but little explanation. spring motor is shut off. great! A is the house wall, B is a shelf, C is a Contributed by an EXPERIMENTER. One must be careful to connect the in- light spring. D is a piece of sponge or absor- wire to the house current wire coming bent material or a small metal receptacle, A "POTATO" EMERGENCY which is not grounded. The incoming wire E is a contact, F and G are wires, H is a RHEOSTAT. can be led into the house along a fence I is a battery, and J is a standard shelf, Are you looking for a rheostat? Then or any other convenient place. vibrating bell. examine the drawing which shows a rheo- The action is as follows:-When the Contributed by HROLF F. LUCK. door is opened contact is made at A. The stat made by sticking a brass or copper rod wood screw is to adjust the movement of into each end of a potato. The resistance the spring which makes contact. When is regulated by bringing the rods close to the wire screen is pushed, it makes con- each other, or by drawing them apart. If tact with the copper plate. Either the this rheostat is used for a continuous period screen or the door will operate the buzzer of over one hour, it will be found neces- alarm, as they are connected in parallel. sary to replace the potato by a fresh one, as the current passing from one terminal Door 'Hinge to the other tends to bake it. This makes a very cheap and simple rheostat, even Tra" Bross Spring

Wire Screen 1 JJ 1, t q,i At on Window iu^ ALIb_` ezurrac's Copper Plate r - om

To House Curren/ 'Buzzer Suffering Mackerel! Yes, It's Another "Rain Pap storcee Alarm." And It Works, Yepl v" V V t , d!oror 'o o S..-. ® tc. © Two Pieces of Wire Pushed Into Opposite ! ! ! Chicken Thieves!! Beware When This Elec- EXPERIMENTERS Ends of a Potato Provides an tric Alarm Is Hooked Up to the Emergency Rheostat. Chicken Coop. Don't forget to write up that little "stunt." It may win a prize. considering the cost of "spuds," which are The switch is to disconnect the buzzer when Address about $4.00 per bushel. Why not grow the door is opened for the day. all manuscripts to the some "rheostats ?" What next!! Contributed by Editor, Electrical Experimenter, Contributed by VICTOR C. MAZYLEWSKI. 233 Fulton Street, New York City. RUDOLPH P. KRAJICK.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 777

greater tension on the armature spring. A Remarkable Magnetograph These directions are intended only to herewith is submitted a print of a spool heads should be laid out and drilled supplement the accompanying sketches. I "double" magnetic field of a horse -shoe before assembly of the spool. In order to have actually made the cut -out herein de- magnet. The cause of this peculiar field is insulate the windings, it is necessary to glue and since it has been in operation, Single that the steel from which the magnet is a thin piece of fibre to each of the heads, I have ui t had a bit of trouble. In made was faulty and order to keep out dirt, therefore causes an it is well to make a unnatural field. How- cover for it. It can be ever, there seems to be I s e d on automobile a break in the original lighting plants, etc. magnet, which is a Contributed by single piece magnet. DAVID MATHESON Contributed by HAL C. BRANAMAN. A GOOD FILTER STAND. A "REVERSE CUR- Those who follow the RENT" CUT -OUT "Experimental Chem - FOR BATTERY istry" course in the CHARGING. ELECTRICAL. ExpERt- The following is a MF.. \TER and conduct description for making the experiments will a reverse current cui- find the apparatus de- Mil for use with six - scribed in this article %olt charging systems. very useful. The material that was The base (C) is six used in the cut -out did inches square and cut not cost anything, the from oak g -inch thick. parts and pieces being At each corner small selected from my col- pieces of ''/ -inch dowel lection of "junk." (D) are inserted in The magnet spool holes bored % -inch consists of an iron bolt deep. The round up- with two pieces of right (A) is 3d-inch in Sheet brass for the diameter and secured ends. The top end is in the base by a screw threaded so that the This Photograph of a Magnetic Field Is Unique in That It Shows the Relatively Large (S). Faulty Piece head will down Change Produced In the Magnetic Flux About a Horse -shoe Magnet by a The piece (M) is of turn of Steel. A "Soft Spot" in the Steel Might Cause Such a Disturbance. and jam into place. oak, Winch thick x 6 About an inch of inches long x 2 inches thread should he left outside to make and to strap 2 layers of paper around the wide. To this bar is glued the piece (F), winding easier. The bottom end has a core. 2 inches square and I inch thick. A wooden and a -inch hole in shoulder cut on it and then the sheet The mountings are made of sheet brass. set screw is made half as shown in drawing. A hole large brass riveted on. The bottom spool head The support for the armature and its (F) enough for (A) to slide thru is bored thru should have extending tabs on it, so that it spring must be made separate from the (M) and (F). Two 1% -inch holes, H can be screwed to the wooden base without head, because it would be practically spool and are bored in (M) hold funnels. damaging the windings. All holes in the bend this tab over after the H' to impossible to A wooden rosette (B) may be added. windings are in place. The contact plate Contributed by D. S. HARDING. must be insulated from the spool head. The contact spring must be insulated from the armature. The armature and tension spring were Ge- taken from a DeVean buzzer, but this combination may be readily made if such a combination cannot be secured. The chief point is that the tension on the spring is adjustable by means of a threaded rod and nuts. The contact spring should be made of spring brass with a flexible conductor soldered thereto. There are two windings on the cut -out. The inner is a high resistance "Shunt" winding, and should consist of about 3 pound of No. 32 magnet wire. (I obtained this wire from a field winding on a fan motor.) Between the inner and the outer windings there should be several layers of paper. The outer winding is a low resistance "series" winding and should consist of three or four layers of No. IS wire. (I have found bell wire very satisfactory.) 'l'he outside of the windings should be well covered with tape and shellacked thoroly to exclude dampness. 'l'he connections should be made as per diagram. flake sure to have the connection at A, make the two windings in parallel Sno/1 M aiding. not bucking. The other end of the Nol % -- series winding should be connected to the " contact plate. The connection from the E ,. \ . contact spring goes to the line. WI'M, Glued Into Adjustments : Tighten tension on spring A until the cut -out %till release when the charging current drops to zero. Then turn down I¿ 0 the stop pin until the cut -out will operate A Compound Wound, "Reverse Current' when the current builds up to charging he Here Is a Good Homemade Filter Stand for Magnetic Cut -out for Battery Charging. It value. In making these adjustments. the Amateur Chemist and Photographer. It Is Automatic in Its Action and Prevents a the armature does not come in Storage Battery from Discharging Back Thru sure that Can Be Built Any Size Desired and Made to the Dynamo. contact with the core as then it will take Carry 3 or 4 Funnels.

www.americanradiohistory.com 778 ELECTRICAL EXPERIMENTER March, 19I8

LIGHTNING EXPERIMENT. A SIMPLE 110 -VOLT RHEOSTAT. A DRY CELL LAMP MOUNT. I was much interested in your article on Take a porcelain tube such as is used Procure a reflector (A) from an old "Thunder- Storms and Lightning Rods" by for house wiring. Procure an S -32 machine - "miner's" flashlight and make an 8 -32 screw Terrel Croft in the August issue of the screw, about 1 inch long, with a head that hole in it near the outer edge. Fasten this fills the center of the tube, leaving about to the negative pole of the battery with inch of the thread projecting beyond the end, a regular battery nut. Make a brass spring Fasten the screw in with sealing wax, tak- clip (B) about As of an inch wide, with Chorgea' ing care that the head on the inside of the leuden Joma tube is not covered. Put a binding post Spoa; on the screw. Take ground carbon about as coarse as the sand from No. 2 sandpaper and almost fill the tube with this carbon. Plug the end with a wooden plug and bore a small hole thru the plug. Now take a piece of stiff wire slightly smaller than the hole and a little longer than the tube. This rod is to increase or decrease the resistance at will by simply pushing it in or pulling it out. The sealing wax, binding post and carbon I obtained from old dry cells. Sporir-+--^ Contributed by ROBERT EASTMAN. 11A

Porte /am Tvbe

' !+ !!!IIÜiÍiIÍ!ÍINhI!uiNl!ph!ÍÍiI . IL Bmdrny Posi SA / Wire Machine Screw A Home -Made Dry Cell Flashlight. It Can Be Constructed From Odd Parts and Gives A Practical Demonstration of the Efficiency Excellent Results. of "Lightning Rods." The Leyden Jar Dis- charges to a Cup of Alcohol, Igniting It, if Wooden Plug : Ground Carbon an 8 -32 screw hole at one end. Bend as Lead Wire Is "Ungrounded." shown and fasten on the carbon terminal ELECTRICAL EXPERIMENTER, and therefore of the battery. To turn off lamp turn clip to Irt take pleasure in submitting the following one side, breaking the circuit. experiment, which I believe will explain For flashing fasten a piece of spring brass thoroly the effect of the lightning rod. to clip (B) as shown in the figure. This A small wooden building is made, thru is operated with the thumb. This outfit can which passes a brass rod extending to be easily adapted to extended carbon types A Simple 110 Volt Rheostat Made of Porce of dry cells. about 2 or 3 inches from the ground, lain Tube Filled With GroundUp Carbon beneath which a metallic container filled Contributed by P. B. KINGSLEY. with alcohol is placed (a tin box cover will do). When a charged Leyden jar (or a CHARGING STORAGE BATTERIES MINIATURE RECEPTACLE. spark from a static machine) is approached ON 550 -VOLT CIRCUIT. In the sketch A is a wooden base 1% to the top of the rod, a spark will instantly Charging storage batteries on a 550 -volt inches in diameter and % inch thick. B ignite the alcohol, but when a chain or wire D.C. circuit can be easily accomplisht, as and B are small brass strips yfi of an inch running to earth is attached to the top, it shown in the diagram, by using incandes- wide and 3{t inches long making contact will be found that the alcohol will not cent lamps in series with the battery so as with the center point of the bulb, and the catch fire, thus proving the efficiency of the to reduce the voltage. Use lamps of 110 - other being soldered to the wire spiral in lightning rod. volt rating each in series of five, being sure the wooden socket. C is a piece of wooden Contributed by EDGAR SINCLAIR. to have the lamps in each group of the dowel stick Vs inch thick, with a hole for the same candle -power and current consump- bulb to fit in snugly. A wire in the shape WHO SAID SHOE -NAIL tion. The lamps may be sixteen, thirty -two, of a spring is fastened inside the wooden SWITCHES!!! or even higher candle -power. The higher socket by means of a pin bent so as to be In the September issue of the ELECTRICAL they are in candle -power, and therefore in used as a staple, and one end is soldered EXPERIMENTER, there was a request for Io a spring contact B. Arrange the wire some genius to come forward with an elec- in C so that good contact is made with trical use for old "shoe- nails." The said the side of the bulb. genius has arrived! Hail, hail!! SSO V AO /r.o ns Glue the wooden shell C to the base A. If small machine Shoe -nails make excellent contacts for S-no tog' brass screws can be tapt multi -point switches, such as those used for /6 eQ ,tlr/lal in strips B and B as binding posts, it receiving transformers, loading coils, etc. will look neater than to put a hole thru The nails are driven into the panel and the brass parts for the wire to pass thru, the leads are soldered to the projecting and twisting the wire around itself. ..nma,er

Parcae b/ . Srn.th d/cdeí 6v- eaomp Shoenoi/ GonlClr` . y ì e Method of Charging Low -Voltage Storage Batteries From 550 Volt D. C. Circuit Thru a Bank of Lamps. the current which passes thru them at full voltage, the greater will be the charging current for the battery. Contributed by PETER J. M. CLUTE.

Attempt No. 1 At Utilizing Shoe -Nails Fo EXPERIMENTERS ! ! ! Miniature Lamp Socket Constructed From Switch Points. Even Mr. Hoover and Dr Wooden Shell and Base, in Which a Wire Garfield Must Rejoice At the Economics Spiral Is Secured to Form Screw Thread For Exemplified. Don't forget to write up that Lamp. little "stunt." It may win a prize. ends. The panel should be thin and of Address all manuscripts to If good contact is made all around, the some hard substance to get proper results. the receptacle will work as good as one bought Next!! Editor, Electrical Experimenter, from the dealers. Contributed by THEODORE SEXTON- 233 Fulton Street, New York City. Contributed by WALTER SCHRODER.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 779

-I FOR FIREPROOFING ANY KIND brushes will tend to peel or turn black. OF FABRIC. Hints arc given in the illustration for at- A very good formula for this purpose is taching the "pigtail" connectors. Wr'ink1e i . as follows: Contributed by H. W. SECOR. Boric acid, 50 grams. Borax, 60 grams. 'oven piy/oó Water, 1,000 cu ems. i!, Paint or soak fabrics in the solution: then either hang up to dry or press fabric P/9 /oii e with a hot iron. Contributed by ALBERT W. PUTLAND. 'Ormui s COPPER -PLATING CARBON MOTOR BRUSHES. It is usual to thoroly copper plate the arm , better class of motor and dynamo brushes EDITED BY S.GERNSBACK caßsñe/ /rie/s Coppery/09er made of carbon to improve their surface i smear conductivity, and this may be accomplisht Under this heading we publish every month Details of Method Used in Firmly Securing useful Information In Mechanics, Electricity in the following manner: Plg -tall Connections to Carbon Brushes. and Chemistry. We shall be pleased, of The carbon brushes are usually cut from course, to have our readers send us any recipes, formulas, wrinkles, new Ideas, etc., flat carbon plates of the desired thickness HAND GRENADES. useful to the experimenter, which will be and measuring 12 by 12 inches. They are It often happens in a laboratory that duly for, upon publication, paid if acceptable. cut out in strips, which are then sepa- some inflammable acid is accidently spilled rated into the proper lengths by means of or some chemicals which do not agree be a high speed carborundum or corundum mixed. A very bad explosion or fire is RESTORING THE COLOR OF wheel about i/a inch thick and 12 inches MAHOGANY. usually the outcome of such mistakes. in diameter, rotating at high speed. A sanitary and safe device can be made by Add TA ounce of Alkanet root, cut small, The brushes are first washed thoroly the experimenter at the cost of a few cents to a pint of linseed oil and when this has and after drying they are dipt in pure which will end chemical fires as quick as stood for about 5 or 6 days add % ounce paraffin, when they are placed in a bake they begin. powdered gum arabic and 1 ounce of shellac oven and heated at 110 to 115° F. tem- It consists of a mixture of chloride of varnish. Let this mixture stand near the perature for 20 to 30 minutes. calcium, twenty parts; sodium chloride fire for a week and then strain. Wash the They are copper plated by immersing in (common salt), five parts, and water, mahogany well with soap and vvater, before an electrolyte bath. For small tanks the eighty-five parts. Several small thin bot- polishing with this recipe. This recipe bath is prepared by mixing two pounds of tles are purchased, filled with this mixture. should be handy to experimenters for pol- copper sulfate with one gallon of water and corked. ishing the bases of their apparatus. and adding ammonia until the precipitate When a fire occurs, one of these grenades Mahogany Stain. Dissolve Bunn Sienna first formed is just redissolved. This should be thrown in such a way that it will in vinegar. colors the solution blue. Potassium cya- break in or near the fire which will quickly To make paper transparent. By dipping loeraOOynat be extinguished. Contributed by the paper in fresh- distilled benzine, paper EDWARD G. WILSON. becomes transparent. This is handy for experimenters who desire to trace designs RADIO -ACTIVITY FROM GAS without using ordinary tracing paper. The MANTLES. paper becomes opaque as soon as the ben- Here is an interesting experiment on zine evaporates and it will be necessary to Radio- activity. I obtained some Welsbach moisten paper again. Ink will not run on gas mantles and powdering them and- ptced its surface when damp. the same in a cardboard box. I then put a Contributed by H. HORTHINGTON. key in the powder and covered it with a piece of cardboard, on \top -6f which I laid a piece of sensitized photographic paper CEMENT FOR CELLULOID. with the sensitized urface down. The Small celluloid articles can be repaired above operations here alf \done in a dark with this simple cement. Dissolve one part room lighted only by a ruby lamp. The of camphor in forty parts of alcohol and Copper Plating Carbon Brushes In Electro- box was thew /covered and left in a dark add an equal quantity of shellac. lytic Bath. room for one week. At the\end of this The cement is applied hot to the parts nid is then added until the blue color period I /found that upon developing the to be mended and the parts are held to- photographic that there was an in- disappears. This bath should be used at paper gether until cooled. impression of the key on the same. a temperature of 122° F. to 131° F. An- distinct Contributed by rays which are a property other bath, which may be used cold, is The'radioactive THOMAS W. BENJAMIN. metal, a quantity composed of a copper sulfate solution with of the rare Thorium, small is contained in these mantels, had 1/10 of its volume of sulfuric acid. Its of which past cardboard and affected the density should register 1.197. This bath thru the LUMINOUS FISH BAIT. sensitized paper. cannot be used for metal objects attacked know that a at- by R. E. RAPP. All fishermen light will by the above chemicals. Contributed fish. The present device tract comprises Pure copper anodes are placed in the a small bottle or vial wound with wire HOW TO CUT THE TOP OFF A bath, and these may be cut from pure spaced one -eighth of any inch apart. Two BOTTLE. copper sheets about inch thick. The hooks are to the end of the bottle '/ a piece of filter or blotting paper swiveled carbon brushes are held by spring clips, Cut with fish line, tying it to the main line in two narrow strips, moisten same and resulting in about % inch of the brush 'above the bottle. A luminous mixture is paste around the bottle, each piece of paper remaining unplated, but this is all right. then made. Heat some olive oil on the parallel to the other, leaving between them as the unplated edge is the one ground stove for about fifteen minutes, just sizzling a narrow space, marking the place where down to fit the and and not boiling; then mix in phosphorus commutator curvature, you want to cut the bottle. Now hold the need neces- the copper plated surface not bottle over the flame of a spirit lamp and sarily reach the commutator. turn slowly so that the bare space is heated The electric current required for a evenly; after about a minute the glass will small plating tank is 15 to 20 amperes at break quite clean and will only need to be 3% to 4 volts, and a regular electro-plat- filed smoothly to take off the sharp edges. ing generator is best employed. The Contributed by G. M. BLUM. brushes are plated from 4 to 6 minutes generally, but this will vary with the tempera- POLE INDICATING SOLUTION ture of the electrolyte and the amount of FOR BATTERIES. Attracting Fish by Means a of Luminous Water. 1 Bait and Hook. current used. Formula.- teaspoonful; A little experimenting will soon tell as Phenolphthalein. 3 drops; Potassium Ni- the size of a small pea. Put in the bottle to how long the brushes should be plated trate, 1 teaspoonful. and cork. This is a fine bait for bass and and as to the proper strength of current. Directions for Use. -Dip wires into can be used to an advantage at night. It It should be possible to regulate the lat- solution, and the one which is negative can be used in winter fishing when the ter by means of a rheostat. If the plat- will color the solution about it red. lines are placed thru holes in the ice. ing is donc too rapidly by using too strong Contributed by Contributed by RICHARD ANDRESS. a current then the metal deposit on the BENSON FREEMAN, JR.

www.americanradiohistory.com 780 ELECTRICAL EXPERIMENTER March, 1918 Experimental Chemistry By ALBERT W. WILSDON Twenty- Second Lesson

APPLICATIONS OF ELECTRO- the equation SO. = SO, T O. the oxygen cathode, in a vat containing a strong solu- CHEMISTRY. being liberated and set free, while the tion of copper sulfate acidulated with sul- ELECTRIC REFINING OF METALS. fórmer, SO., having a strong affinity for furic acid, and a bar of copper forms the THE process of electrolytic refining water combines with it to form sulfuric anode, as was the case in the refining proof metals, altho wide in application, acid, which at once dissolves from the cess. Copper is deposited on the grafite has as yet been chiefly restricted to anode to form copper sulfate. which is cathode of wax to any desired thickness. the refinement of copper. The metal + + -- and it reproduces faithfully every projec- has been obtained as "blister" copper ionized to Cu and SO., and the operation tion. indentation and line of the original. from its ores, sulfids, oxids, etc., containing is rendered continuous. No new supply It is permitted to remain in the bath from of sulfuric acid or of copper sulfate is needed. The bar of impure copper becomes reduced as the refined metal increases at the cathode. The tank house of one modern electrolytic plant for refining copper is 600 by 200 feet, contains 1,600 depositing tanks. each having 22 copper anodes. each of which weighs about 400 pounds. These are put in place by means of cranes. and after being allowed to remain in the tank for about 43 days the remnant is taken out as scrap and resmelted. The cathodes (refined copper) are taken out every 7 days with the employment of cranes, a tankful at a Molssan's Electric Furnace. Space Is Pro- time. Slimes are removed once in three vided at "B" for Substance to Be Electrically Arrangement of Apparatus for Electrolysis Melted. In Such a Device Small Diamonds of Copper, Etc. AAnode, C- Cathode, Both months. The liquid contains from 12 to Have Been Made from Carbon. Immersed in Solution of Copper Sulfate with 20í'r copper sulfate, and from 4 to 10% of Sulfuric Acid. sulfuric acid. three to eight hours, depending upon the many impurities which it is necessary to The electrolytic refining of zinc and thickness desired. The film of copper does remove. A solution of copper sulfate with nickel have also been tried on a large scale not adhere to the wax or grafite, and can be some sulfuric acid is put into a vat or tank, but have not been as yet entirely successful. easily removed by hot hydrochloric acid. which is connected with the source of dec- The zinc deposit has a tendency to be After removal from the moulds, the back is tricity, and a bar of thick plates of the spongy and readily oxidizable and the cleaned, a thing layer of tin foil is melted crude impure copper is then suspended in nickel ores require previous smelting and on it, and finally it is filled with molten the solution, and made the anode. The contain many impurities. type metal to render it rigid. The face is cathodes consist of very thin plates of the then of rigid copper, which is mounted on pure copper. (See Fig. 105). a suitable wooden support, called a block. The curent causes the copper ions from This copper electrotype is harder and more the copper sulfate in solution to deposit on lasting and durable than type metal. the copper cathode, while the sulfate ions Copper is practically the only metal used at the anode form a complex reaction, the for electrotyping. Recently a process was result of which is to dissolve off more invented for electrotyping by steel, which copper from the anode. thus tending to is much harder and more lasting than keep equilibrium in the solution. The im- copper. but its drawback lies in the fact that purities from the copper anode gradually it rusts, and it probably will never entirely settle in the bottom of the tank, and only supersede copper. pure copper collects on the cathode. Mil- Electroplating. Electroplating is the lions of pounds of copper are refined by electrolytic deposi- this process each year in the United States, Modern Method of Obtaining Pure Aluminum tion of one metal upon another. It differs and since the beginning of the European by Electrolysis. A Set of Multiple Electrodes from electrotyping in that the deposit of War (Carbon Anodes -A) Are Inserted In the Ore copper or other metal is fixt permanently the output has increased to a very to Be Reduced as Shown, the Molten Alum- on the surface of the base metal, which marked degree, having changed from a pur- inum Accumulating at "O." forms the cathode. and is not removed. as ity of 95 or 98% to practically 100%. This was the case former is called electrolytic. or refined copper. The recovery of metallic tin from scrap of the process. The metals employed for electroplating Native copper from Lake Superior does tin plate is another application of electro- chief are; gold, examples of which work are not need this refining, and usually sells for lytic refining that has been developed quite gold- plated watches and cigarette cases, etc., a fraction of a cent a pound higher than the ektensively in recent years. It takes place electrolytic variety. in alkaline solution and the tin goes into silver, used to plate knives and forks, etc., Theory. solution as an alkaline stannat. nickel, copper and platinum, and such alloys as brass and German -silver. The theory of this action is that the The electrolytic refining of silver and its The cathode, which may be iron. copper sulfate molecules break up separation from gold and platinum con- copper. into brass, copper and sulfate ions by solution. When tained in the silver bullion is also exten- bell metal, or other base metal or alloy, is first very the current passes, copper ions deposit sively practised and is gradually supersed- thoroly cleaned with as . ulfuric acid to rid the surface of all traces copper atoms on the cathode, (C in Fig. ing the method of "parting" by nitric acid. (Continued on page 801) 105) ; sulfate ions at the anode (A in Fig. Electrotyping. 105) become sulfate radicals, and at once The process of electrotyping is almost the break down into SO. and O. represented by same as that described in refining copper. Most hooks are now printed from electro- types. as are the entire pages of this journal, and they are also employed for printing maps. illustrations and numerous periodicals. etc. The type is first set up. making pages of the size desired. An impression is made of the type or wood cut in a mineral wax, which is composed of a mixture of bees- wax. turpentine and grafite. so as to have an exact opposite of the face type; that is, the projections of the type form indenta- tions in the wax. The plate is called a case. and is impregnated How Silver -Plated with a fine coating Articles Are Coated with powdered of Hydro Precious Metals by Electrolysis. The Spoons. of grafite which affords the con - Sectional View the Gigantic -Etec Etc., Form the Cathode, a ducting surface. These impressions tric Plant at Niagara Falls. A Case of Utiliz- Bar of Silver arc ing the Chemical Action of the Sun's Rays Serving as the Anode. hung from copper hooks, and form the Indirectly.

www.americanradiohistory.com March. 1918 ELECTRICAL EXPERIMENTER 781

Our Amateur Laboratory Contest is open to all readers, whether subscribers or not. The photos are judged for best arrangement and efficiency of the apparatus. To increase the interest of this department we make it a rule not to puhli.h photos of apparatus unaccompanied by that of the owner. Dark photos preferred to light toned ones. We pay each month $3.00 prize for the hest photo. Make your description brief and use only one side of the sheet. Address the Editor, " \Vith the Amateurs" Dept.

I "Electrical Laboratory" Contest i As announced in this department in the February issue, we are desirous of publishing each month a special article describing an exceptional Amateur Electrician's experimental laboratory. Stich a laboratory will he found illustrated and described with several excellent photos on another page of the present issue. For prizes and instructions in preparing the articles and photos sec the February issue. We now wish to say a few words with regard to the present laboratory contest. We are pleased to bring to the attention of all Radio and Electrical "bugs" two ex- radio amateur enthusiasts, who are shown in the photos at the upper right and left corners of the group. At the left we have a photo of. the wireless set used prior to the war by Miss Edith Charmont of Cleveland, Ohio, and who has now joined the American Red Cross. She will probably go across the ocean and join in the "big game" before long. \Ve are pleased to introduce a well -known ex -radio amateur-9 TL-known to his friends as Forest Longbrake, of Sheffield, Mo., but more recently of the 313th Field Signal Battalion at Camp Dodge, Iowa, and who expects soon to "go across" to France. Mr. Longbrake mentions that he has done lots of long distance work in the good old amateur days, with the set illustrated in his laboratory below. Once more-don't forget to read the important announcement in the February issue. Address all photos and manuscripts to the Editor "With the Amateurs Prize Contest."

A CROUP OF REPRESENTATIVE AMERICAN AMATEUR LABORATORIES. Forest Longbrake, Sheffield. Mo. Electrical Laboratories of, 3 -Chas. P. Mc Radio Stations of, 1 -Miss Edith Charmont, Cleveland, Ohio; 2- Whitney, Laughlin, Cadiz, Ohlo (First Prize); 4 -Ralph P. Anderson. Selma., Calif.; 5- Vernon Clements, Elmwood, Nebraska; 6- Carroll Waterloo, Iowa; 7 Frank Henninger, Pawnee, III.; 8 -Scott E. Vance, Hillsboro. Ohio.

www.americanradiohistory.com 782 ELECTRICAL EXPERIMENTER March, 1918 $L11E5T__PATEÑtS

Door -Light for Autos areas. Means are provided, such as ner shown. The diametrically op- device is provided with electric motor (No. 1,248,930; issued to Albert C. by an electric blower for remov- posite quadrants are connected to stabilizer, and the various electrical Schulz.) ing the ionized air and metal gases opposite sides of the battery so as features involved in the operation An idea capable of wide applica- from between the edectrodes and to be electrified, negatively and posi- and orientation are controlled from tion and providing electric light on simultaneously cooling one electrode. tively respectively. the surface of the water by means the step of an auto whenever the while means are provided for re- of electrical conductors leading door is opened, while the light on taining the beat of the other elec- Electric Piano Player downward thru a well insulated the closed door lights up simul- trode, to permit the generation of (No. 1,249,157; issued to Alcide H. cable. The outfit is provided with taneously, and thus illuminates the cathode rays. Maitre and Victor H. Gaston a shock absorbing member at its Martin.) lower extremity in the event that Automatic Electric -Light Buoy the device might be lowered too rap- (No. 1,248,850; issued to H. Hart- idly in some instances. man.) The main object of this device is Stereoscopic X -Ray Apparatus to provide an independent and auto- (No. 1,250,093; issued to William D. matic electric light buoy of simple Coolidge.) construction, which can generate its The invention requires the use own electricity for lighting a lamp of two X -ray tubes, connected in a at its mast head without batteries certain manner to a high tension or other apparatus requiring con- transformer, while the successive stant or periodical maintenance. The images produced by these two X -ray device comprises certain mechanical tubes on a fluorescent screen are features whereby motive power for viewed in proper relation, first by driving a high tension magneto is

funto; I 4'6 +n floor of the car. .The lights are supplied with current from the car's This patent deals principally with storage battery or from dry cells. a unique electromagnetic interrupter and are controlled by automatic for producing musical sounds such switches mounted behind the doors. as by vibrating the strings of a The circuits are inter -wired so that piano or other instrument. The de- the lamps light in the manner above vice is claimed to damp out false described. A glass window is placed vibrations, and to suppress extrane- in front of the lamp as well as ous noises, so as to give a pure underneath the lamp, so that the sound. The electrical interrupter light shines in a horizontal plane as contacts are subjected to the vibra- well as a vertical one. tions of the spring. There is also provided an independent spring pressing one of the contact members into engagement with the vibrating Electric Ice Cutter musical spring, so as to cause the (No. 1,250,010; issued to Germain sonorous vibrations of this string to Pouchan.) faithfully react on the interrupter A clever invention intended for contact spring. 2 use in hotels, restaurants, etc., for the purpose of cutting ice into small Combination Magneto and Horn blocks or cubes for table use. The (No. 1,249,255; issued to H. R. inventor provides in this device one Van Deventer.) or more sets of wires which are A combination dynamo or mag- heated by electricity and to he kept neto and auto horn of simple de- in contact momentarily, and thus the sign. The magneto is driven con- bot wires melt their way [bru the stantly as in the regular auto equip- ice. By using a suitable number ment, and the born is mounted one eye of the observer and then at one end of the magneto frame as by the other, in perfect synchronism with the current impulses so as to produce the effect of an image seen in stereoscopic relief.

derived from the constant wave ac- Electric Boiler tion of the sea. A heavy weight (No. 1,251,116 issued to Ora E. is mounted on the main sbaft of Sarr.) the mechanism so that as the buoy This invention appertains gener- pitches about on the waves, this ally to electric boilers, and aims to weight follows the law of gravity provide an improved form of elec- and swings hack and forth. The trically heated steam generator, magneto is connected in series with wherein steam for operating an en a lamp of the Geissler tube type, gine or other device is produced and a suitable condenser. of sets of such wires, the ice may Electric Ore Detector be cut in as many planes as is de- (No. 1,248,380 issued to Rupert shown. By means of a sliding gear sirable. In cutting it into cubes, it Nelson.) and a lever connected with a control must be cut in three planes at right Different metals can be substituted rod and handle, leading up to the angles to each other, and in this for the electrode that is inserted driver's seat, it becomes possible to case the inventor provides three sets bring a pinion into contact with a of parallel wires, the wires of each stud on the diafram of the born set to be so positioned as to cut and thus cause it to operate. the ice in the manner above described. titCIROYCTIR .. Submarine Movie Camera (No. 1,250,582; issued to H. Hart man.) High Tension Rectifier (No. 1,251.269; issued to A. Mul- vany and E. Kennedy.) The high tension rectifier here shown is intended particularly for use with Xray tube circuits, for the purpose of converting high tension A.C. from the secondary of a step -up transformer into a high potential uni - directional current.

WPM into the earth, so as to determine whether the ore is positively or by the passage of an electrical cur- negatively electrified with relation to rent thru the electrode, water, circulating around thus ascertaining into and between a series of oppositely what class the ore belongs. The charged electrodes the of apparatus employed for the purpose in form includes metal plates, these plates being sus- a source of current such as This apparatus provides for the pended in the water within the This rectifier takes advantage of the a battery and a quadrant type elec- taking.of submarine motion pictures boiler. The patent covers special electrostatic field intensities sur- trometer, connected up in the man- at various depths of the sea. The means for suspending the electrode rounding electrodes of different COPIES OF ANY OF THE ABOVE PATENTS SUPPLIED AT 10e EACH. plates within the boiler.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 783 Phoney Patents Under this heading art puhllaht electrical or mechanical Ida which you hven't smell of the Patent yet. Alter they bave allowed the Pat- our clever Inventors, f heat known to themselve, have as vet ent. you must pay another $20.00 as final fee. net patented. We That's $40.001 WE furthermore cell attention to our celebrated Phoney PAY YOU $3.00 and grant you Phooey Pstaot In the bargain. so you Patent Offisa for the relief of all suffering daffy Inventor In this country $43.0011 When sending In your Phooey Patent application, as well as for the entire universe. he ure that It Is es daffy as a loesick hat. The daffier the better. We revolutionising the Patent butanes. and OFFER YOU THREE Simple ketche and short description will DOLLARS ($3.00) FOR THE BEST PATENT. If you take help our Left! of Phoney your Phoney Patent examiners to Issue a Phoney Patent on your Invention In e Patent to Washington, they charge you $20.00 for the initial lee and then jiffy. PHONEY PATENT OFFIZZ PRESENCE OF S/cLN,r (EXTRA LOW) THREE U /ILE SHOWERS OF THE GOGNE, ARE \^'f 9 711AcA LA - 7RALA LA

ACH. LoO/E VATA SCHNELL

/4-a -11J///r /- Prize Winner. SKUNK GASSER. "Well, I've Been Skunked." Will Soonr` Be Heard Among the European Trench Inhabitants -at Least Just as Soon as I Can Get Official Washington to Consider the Merits of My Sure -fire Hun Destroyer. Several Hundred Battalions of Tame Skunks Are Hitched to Small Two -wheeled Carts, Each Containing a Dynamo, Motor, Storage Battery, and Spark Coil. Dynamo Charges Battery, Which Runs Motor. Motor Drives Cart. Skunk Can't Stop Once Spark Tickles Him. The Limburger- lovers Are Soon "Skunked" and the Sammle. Do the Rest. Inventor, Rex Purcell, Mo. Valley, Iowa.r P% 62 © [( /4" + : a et-ó - , O /} 132.2 s ,hi _ I ,_ IA ))_ )'_ i----) ff ' " , " ' _ 1 JL7C`1= 1 i" b, :i f:-, C r l- i-i 1 " tr I . ( 1-i 11-i WATE L`-' - , I ell COCKTAIL NOON /,., I V ._`o/ aTM ./(! _ ;` / O SNANeR ORNRR //. 0 `\F /4%7/, /// ¡ NMIir///I /NLE7 , i _ arN0' aeA.°L rAM°' =- 37- - ////////. . I KMte ó scs _ á _ = 4 ©, pr © _ _ //ii, I I ALARM ye 1M[ATeR BRICK _ _.Qi. .///, 1 TNR N[R cuuc i - ii/ I é + 0' - BELLOW .-l , _ ,^v-1' . , . , /% l,l%/l/- /////'// //i/l il 7,/iii 1- HEATER fOR BATH f////////l / lïlll%l WATER rforoR 2-0007(TAIL SHAKERfORNORN/N6 , V ,(FLYWHEEL 3 WINDOW OPENER ErE OPENER -_GE0(ts 4-BAC/( SCRATC'IfER \ 5 -,;' 'r 6,. 5-READING LA/)'JP pYNAMO 6-ELECTR/CFAN , '' ¡I,

7ELECTP/CNEATER I

8-BR/CKTHROWER I FOR CHAS/NG /vOC i e ? A 9 ALARM CLOCK TURNAL CATS OppE T !° STORA6E 8A rrE/ey HYDROELECTRIBEO. Do You Sleep? Sure You Dol Well, Here's the Latest Convenience for All Those Who Hlt the Hay, either Perl. odically or Regularly. Just Before Retiring. Turn on the Water -valve Suppying the "Mattress Bellows." You Rise as You Snore, and While Sleeping Produce a High Pressure In the Bellows. This Water Pressure Runs a Turbine Connected to a Dynamo. The Dynamo Charges a Storage Battery. The Latter Furnishes Electric Current Free of Charge for Electric Light, Heater, Cock -tall Mixer, Fan, Alarm Clock, Ad Lib-Ad Infinitum. What More Could Mortal Want? Inventor, John Renault, Angers, France.

www.americanradiohistory.com 784 ELECTRICAL EXPERIMENTER March. 1918 QUESTION bOX

This department is for the sole benefit of all electrical experimenters. Questions will be answered here for the benefit of all, but only matter of sufficient interest wilt be publisht. Rules under which questions will be 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 else written in ink, no penciled matter considered. 3. Sketches. diagrams. etc.. must be on separate sheets. Questions addrest to this department cannot be answered by mail free of charge. 4. If a quick answer is desired by mail, a nominal charge of 25 cents is made for each question. If the questions entail considerable research work or intricate calculations a special rate will be charged. Correspondents will be informed as to the fee before such questions are answered.

SUPERSENSITIVE MICROPHONE. SQUIRE'S WIRED WIRELESS. ly to a single wire, and each of these sta- (S94) A. E. ,lazier, of Oakland, Cal.. 1896) Cyril Thorn, of St. Louis, \lo., tions are honed to a separate or individual requests: asks: frequency. The transmitters of each of Q. 1. Will you please publish a diagram Q. I. In number 9 of Hawkin's Electri- these stations are equipt with alternating of the interior parts of the Super -Sensitive cal I:uides, on page 2337, a method is ex- current generators supplying currents of Microphone such as is used for detective plained whereby you can telephone or tele- frequencies corresponding to those used in work and explain parts of the same; how graph over a single wire. without using a the receiving stations. so that by mean, of return wire. It is called Squire's !Wired a switch one can control the frequencies Wireless. As it does not describe fully how very easily. \ \'hen the party desires to ob- this is done. 1 do not understand it. and tain a certain station. he merely throws would like to know how it works. over the switch controlling the frequencies to the particular frequency of the desired 'station, and thereby he is able to communi- IIVIIIIImIlII I jr illE MEIBIll ui rut 111111151111M35 H cate with said station. No two different z ODD PHOTOS WANTED AT frequency currents can interfere with each $7.00 EACH ! ! ! other : thus the selectivity of the system. The first station might have a frequency Now is the time to make your 6 of 30,000 cycles per second ; the second Kodak pay for itself in a real practi- station a frequency of A/eto/ shei/ Corbon cup Carbon E 33.000 cycles per bo//s cal way. We are after interesting FA second. etc.. etc. It photographs of out-of-the-ordinary M. Sectional View of Super -Sensitive Micro electrical, radio and scientific sub- n phone as Used in Loud- Speaking Telephones jeers and are willing to pay $1.00 cash WAVE METER QUERY. For Detective Work, Interior Telephone O" for every one we can use. Please M 4,S97) John Halson. of Baltimore. \Id.. Systems. Etc. bear in mind that for half -tone re- wishes b, know: does it differ from the telephone trans- production in a magazine, a photo- Q. 1. How to utilize the wave meter for mitter? graph should be particularly sharp M obtaining. the wave length of a distant sta- and A. 1. The diagram herewith gives the clear. Of course, if a subject tion. to us schematic arrangement of a super -sensitive happens interest particularly A. 1. The manner in which you can microphone as used in detective work. The sell, we can have the photo retouched. apply the wave meter for measuring the For the run essential parts of such a microphone are general of subjects, how- B wave length of a distant station is by ar- the container, usually made out of metal. ever, it does not pay to go to such ranging the apparatus as indicated in dia- expense. Therefore, take the carbon diafram and a carbon cup. A please pains gram. The received signal is first tuned to é to very high grade of polished carbon balls are properly focus and expose your the required wave length of the distant used in this carbon container, and the car- pictures. it often happens that a station by varying the various inductances really mediocre E- bon diafram fif which is so adjusted that subject well photo- and capacities in the receiving circuit. Then they touch this diafram very lightly. graphed wins approval over an ex- by introducing a buzzer excitation circuit cellent The main difference between an ordinary subject poorly photographed in the secondary circuit as indicated. and And don't send us film telephone transmitter and that a plate or "nega- receiving this excitation current in the of super- rives" sensitive type is the way in which the car- send unmounted or mounted ;_ wave meter, resonance between the secon- bon grains are utilized. In "prints," perferably a light and a dark dary and the wave meter will indicate the the super- sensi- one. tive microphones, carbon balls and a car- wave length which was originally received is to what to photograph: Well. bon diafram are used. together with a by the receiving set. By referring to the fair- that's hard for us to say. leave ly heavy current and a low resistance á lie original calibrated curves of the wave meter tele- that up to you, and every reader now phone receiver, having a resistance of the wave length of the distant station is thus about 5 ohms has the opportunity to become a re- obtained. ® porter of the latest things in the realm of Electricity, Radio and Science. Q. 2. What causes a double humped ELECTRO- MAGNET. But, please remember -it's the "odd, resonance curve in an oscillatory circuit in (895) W. i \I ace, Marshfield. Ore.. novel or practical stunts" that we are a transmitter? writes: interested in. Every photo submitted A. 2. Too close coupling between the Q. 1. Please give in detail specifications should be accompanied by a brief de -- secondary and primary circuit results in a for an electromagnet necessary to pull an scription of 100 to 150 words. Give double humped curve. iron lever thru 90 degrees into a horizontal the "facts" -don't worry about the position. There is very little resistance on style. B'e'll to that. a. lever; attend Enclose this approximately an equivalent of stamps if photos are to be returned three pounds' pull. I would like to know e and place a piece of cardboard in the the amount of wire. size of wire, size of envelope with them to soft prevent ntutilo- iron core and amount of current neces- ® tion. Look around your town and sary. 1 have unlimited current. see what you can find that's interest- A. 1. A suitable electromagnet for ob- ing. taining results such as you desire is speci- Address photos Editor "Odd fied below: The to- soft iron core should con- Photos," ELECTRICAL EXPERIMENTER. M Sec olíec sist of a soft iron bar ',. inch ni- in diameter rd 233 Fulton Street, . \'ew York City. a ameler. tirCUi' and 3 inches long. Fiber bobbin ends 2

1 IFC71I.,11, T"u:i 1iÚ ICI lU1111i luí p1filiEBf inches in diameter are placed at each end 7 g EME of this iron core, and then fully winding A. 1, The operation of Squire's Wired the intermediate space of said bobbins with Wireless is dependent upon the transmis- No. 22 B. & S. 1). C. C. copper magnet wire. sion of alternating currents of different Circuits Used in and die Determining the Wave end, of this winding should be (above audibility) frequencies over a single Length of a Received Signal By Means of brought out thru two holes protruding thru line. the Wave- Meter. the end bobbin. The winding should be Let us suppose that the equipment is to carefully protected by covering it with tape. be utilized for the transmission of telegraph ILLUMINATION QUERY. Voltage used 12 volts and current about .75 and telephone messages. Several telephone (898) Paul Johnson, of Detroit. Mich.. ampere. and telegraph stations are linked electrical- desires to know:

www.americanradiohistory.com March. 1 9 I 8 ELECTRICAL EXPERIMENTER 785

Q. 1. \\ hat disadvantage has a frosted glass upon an incandescent tungsten lamp? A. I. There are several disadvantages from using frosted glass on tungsten lamps; namely, the increase of temperature tvithin the bulb due to multiple reflec- tions of the irregular surfaces produced by the frosted glass, which naturally decreases the life of the filament due to the operation of the filament at higher temperatures. Secondly, the decrease of surface illumination produced by such a lamp, due to a gath- sections ering of dust in the fine irregular Of V V r/ v1 , frosted glass. of the ;vrIIFD APR 1ED " "i APPLIED APPLIED Q 2. What are getters in incandescent lamps? 31(lRICIT1 t,HTRICi11 t A. 2. Getters are chemical compound: which are used to absorb the vaporized tungsten produced by the heated filament and retransferred back to the filament in order that the filament will be kept at the some thickness as it was originally. This retransformation is a chemical process, and very little is known about it, as the commercial companies are keeping it secret. Flowerer, it may be said that originally, when the incandescent lamp was began, that halogen members of the chemical grout' were utilized, viz.: bromin and iodin. a micron? Q. 3. What is ...,r.rr A. 3. A micron is the unit of intensity . of illumination and is numerically equal to r i one one- thousandth of a millimeter.

ELECTRIC OIL AND WATER FINDER. (899.) %lr. Phil Buracker 528 Down- SEND NO MONEY ing St., Denver, Colo., asks for data on : USE THESE ELECTRICAL BOOKS SEVEN DAYS Q. 1. A special form of "Hughes' balance" for locating underground ore, etc. AT OUR EXPENSE A. 1. Concerning special form of the IV merely filling in and mailing the coupon below you can get this tuugllrte set of the

Hughes' induction Balance for locating Cyclopedia of . \'plied Electricity on trial. Pay only small shipping charges when metallic masses buried in the ground, etc., they arrive. Use these books for seven full days before you make up your mind we would suggest that you read the article whether or not you want them. If you keep them, you may pay the special adver- appearing in the August, 1916 issue of tising price in easy installments of $2.00 a month. If you don't want them. you may THE ELECTRICAL EXPERIMENTER. copy Of send them back at our expense and you won't be out a penny. which we can supply at 20e. This article contains the basic principle A MASSIVE ELECTRICAL LIBRARY- NOT HANDBOOKS upon which all such apparatus, of no mat- These seven splendid yuhuncs contain all the knowledge you need in order to earn ter what size, should be designed. With big money in the electrical field. They are not thin handbooks, but thick, enccclopedia- regard to the size of the inductance coil. size volumes, handsomely bound in half morocco leather. gold stumped. Each one these can be of any dimension desired, hut, measures 7 by 10 inches. and is 2 inches thick. of course, the size of the wire and the use large and comprehensive illustrations, plates. Ilia - number of turns on each coil will have This big size permits the of etc. 3,000 are contained in the Cyclopedia's 3.500 pages. to be judged by experiment to a large ex- grams, Over cuts tent. Considering that the coils are made The completeness of the Cyclopedia will be a revelation to Reed These Subject& in with a fairly large number of turns you. Everything electrical is explained in plain, simple Elements of ElectAcitr- proportion to their size, then the problem technical point is made clear. Each volume Electrlcal Measurements English -every -Underwriters* Recuae- of exciting these coils properly is mostly is carefully erns:- indexed for instant reference. meute- Theory. Calcula- a matter of experiment. and one which can tion. Design and Con - For this sum insignificant struction of Generators be solved quickly. -an and Motors Dynamo- one - this wealth of electrical -Machinety- If a buzzer fitted with an auxiliary bat- 5 0 c a Week Electric is yours. But you don't have to send us a penny LtaLitton M&tàlnery- tery contact is used as described in the information P o w e r Traasmisdm- until you have used the hooks for seven days. Then, if you Electric Rauwora-Power article above mentioned, to excite the two stations Switchboards only $2.00 a month - primary coils of such an apparatus, then decide to keep them, send -50c a week - and Switching - Storage price of $19.80 has been paid. Batteries- Applied Elee- it is but necessary to increase the battery until the special advertising tro- Chemistry -- Electric 'l'he regular price of these pay- raising books is $85.00. Elevators- Electric Weld- current or number of batteries in this ex- ing and heating wire citing circuit thru the primary coils, and and wireless Telegraphy. the sensitivity of the entire outfit checked Consulting Service Free up by approaching the coils with a metal .\ year's Consulting Membership in the American Technical - - - -, . - .. . price $12.00-will be included with all or- mass such as an iron tank or any other Society-regular ¡AmericanAmerican Technical Soclab tiers :1 limited time. The advice of an entire corps of nietal object of fair size which may he at for Dept. U.S.A. hand. electrical experts is yours to help you in your progress- e a l'Ieasesend ale theeyclopedla The diameter the coil bobbins for o whole year 1'iIEE! of two of Applied Electricity for seven or forms used on the French "shell locat- will ing" balance measure about 2y feet in Send No Money -Just the Coupon ,' net shipping charges. l dé cede to buy, I will send diameter, and one primary and one sec- hooks before you buy. Re- a you Stil See these for yourself y e iii seven days, and the balance alat ondary coil are wound on each of the two member. you don't risk a penny or assume a single g the rate or $2.00 a mourn. bobbins, these bobbins being supported obligation. 'the books will be sent to any one with- s $I9.91 has been paid. Then sou wilt send me a from a transverse bar carried on a light of United States or Canada, receipt showing that in the boundaries the e the act of books and the $12.00 coo - two-wheeled truck so as to be readily ;uul they may he returned nt our expense if they sulung membership nee else and fully pushed along the ground when in use. you st act now! This paid tor. It 1 think that 1 can get along fail to please. But without Q. 2. What is meant by the term "layer be indefinite- the books, I w111 return them °enrrons offer cannot continued alter seven days, at your expense. on later ?" h. Send the coupon now. 2. A. With reference to the term "layer le . \'ante oit layer," this simply means to follow the AMERICAN TECHNICAL SOCIETY usual construction in winding clectro -mag- Dept. E -7443 CHICAGO, U.S.A. 1 Address nets or other coils and when one laver has been wound on, the second layer is wound / Reference Von benefit by mentioning the "Electrical Experimenter' when exiting to ad :ertisers.

www.americanradiohistory.com 786 ELECTRICAL EXPERIMENTER March, 19I8

over this in the usual manner, back and forth until the required number of turns have been placed on the coil. Q. 3. Is there any form of electrical oil and water locater? A. 3. Yes, an English concern has evolved a very successful electrical apparatus for this particular purpose, which has been approved and used with success by the engineers of the British government both in England and in foreign countries; particularly in India, where it has heretofore been extremely difficult to successfully locate flowing water in order to bore the necessary wells, of which a very large number exist in that country. The principle on which the instrument works is the indicating of the presence of currents which flow between earth and atmosphere, and which, seeking the path of greatest conductivity are always strongest in the vicinity of subterranean water courses, the waters of which are charged with electricity to a certain degree. In taking observations, wooden pegs are Whether You Are Drafted or Not placed at intervals of twenty paces in a direction usually S. E. to N. W. The in- you cannot afford to shut your eyes to the fact that one of the most strument is tried over each of these pegs important branches of the Army, Navy or Aviation branch is WIRE- in turn, and should the needle move on any one of them, tests are made all round LESS : particularly for entering the Signal or Aviation branch of the it, and the spot where the greatest move- Army. When called to the cantonment you must know wireless, and ment of the needle is obtained is where know it well. There is no branch requiring more trained men than the the boring should be made. If the needle wireless section. does not move, subterranean water does not exist under the spot where the instru- SPECIAL WAR RATES ment is fixt. The instrument Send stamp for catalog giving facts. Resident classes indicates water courses open the entire year. flowing underground in a natural state, (NATIONAL RADIO SCHOOL, 14th and U Ste., WASHINGTON, D. C. and not water pipes or sources that have PHONE NORTH x,sl sprung up to daylight. Observations should always be taken on a fine, calm, Navy Needs 1000 Operators NOW clear day between 8 and 12 in the morning L and 2 and 5 in the afternoon, these being the hours of greatest activity of the vertical earth -air currents. Send us stamped and self -addrest envelope and we will gladly give you the name of the concern $ Complete making this apparatus. Junior Deaf Phone ImpairedpHearing 1 5 THE Mit hO1'HO JUNIOR DEAF -PHONE is a super -sensitive Instrument which has been developed to meet the demands for a practical and efficient hearing MISCELLANEOUS QUESTIONS. device at an extremely low price. It is equal to any $35.00 instrument made superior to most of them. and The outfit consists of One Super -Sensitive IIIIMIf11gaIMIX1011D111N111a1t11@111\\0.. SPECTRUM OF THE AURORA. Transmitter with cord connector; One Super - (900) A. D., Sensitive Ear Piece with small black cord; One San Francisco, Cal., writes Black Single Headband; Black Case and Two the "Question Box": Batteries. IMPROVED Q. 1. Is anything positive known about Super - Sensitive Microphone Only $7.50 the nature of heat lighting? r, is A. 1. With reference to the exact na- : - 1 1, Inlmri. ,r rod.. ture of heat lightning, nothing specific is known concerning this phenomena, but it is generally conceded that heat lightning NEW DETECTAGRAPH $15 is nothing more nor less than the reflec- This detr.tira irc:r,mert of minet-us ron,itaiity tion of powerful lightning discharges at a an [x: L...I I r den

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 787 and the degree of luminosity depends upon eral other leading experts on this class of QUICK, RELIABLE, EASY the pressure of the gas due to its expan- device. sion, etc. The spectrum of this illu- (b) This is a somewhat complex sub- minated gas is the same as when excited ject and we would suggest if you have SHORTHAND by any other means, such as by the appli- not already consulted back issues of the cation of electric current. General Electric Review that you would do LEARN IN 5 (c) The explosions of incandescent hy- well to look up some very interesting drogen witnessed during total solar eclipses, articles on the subject of selective reflec- HOURS and also the illumination of gases in tion which appeared therein about one year Absolutely astound- nebulae are undoubtedly due to the pres- ago. ing - the quickness, ence of nascent hydrogen and also oxygen, In general, it would seem reasonable to certainty and ease with which by the electrical disturbances occur - suppose that the molecules in a certain which you learn K. I. ing in these gases cause sudden molecular structure cease to be neutral when they Shorthand. No long explosions. This is most probably due to are set into vibration by the application of period of study; high "Talk to fart a, you means, such as by the rays eliminated like. 1 am taking it the electrical bombardments of the gase- some external expense - down in K. I. ous ions, this causing the gas to become from an X -ray tube or by ultra -violet light here's the g e n u i n e Shorthand" luminous. from a spark gap, arc light, etc. method: (d) So far as we know there is no You will find it worth your while to Try This Specimen Lesson such thing as a phosphorescent gas. consult several of the newer books treat- we Q. 3. (a) Where can I buy a book treating on molecular structure, and take in 5 Minutes ing such subjects as unipolar lamps illu- pleasure in suggesting one of the very minated by High Frequency Currents; latest works in this direction entitled "The here's\ p nnd, this is o a Write Fleming valves, Cooper -Hewitt lamps used Electron -Its Isolation and Measurement ` as valves and vacuum tubes containing and the Determination of Some of Its the two togother, and you have O rn three electrodes used as detectors for Properties," by Prof. Robert A. Millikan, Hertzian waves. (b) In the study of se- one of the foremost scientists in this Here's .( To rake ;.nth you sir- research. Our lective reflection there is a point I fail to branch of philosophical \t -h grasp. We are informed that certain sub- "Book Department" can supply a copy of ply ..rite N and with these two easy stances possess systems which vibrate with this book at $1.60 prepaid. of your pencil, you hr.ve well defined periods. These systems re- rovcrents 16 p e n c i l flect light falling on BELL TELEPHONE SYSTEM. rrde a word that needs the substance only THE when written in 10 n g h end, when the incident light is of the same fre- (901.) L. Slack, of Pittsburgh, Pa., asks: movements- quency and in this case reflect it totally, Q. 1. Kindly give me some information a'cre's I t so tt_ is cosy to mite

at, tnp nnd ÿ pnt. 1 Answer Co/ /ing Sobs nberc Already you havn lcnrned four H.T. Jour: (P/ug G/ug ) horthnnd signs you won't forget. rfth the other signs and ensy directions you can learn to indicate every vrord in the di et i o nary in tire re- Re,xo/ing quarter to twentieth of the quired in ordinnry rrtting, as rn p- Co// - idly or words nra spoken'. /Pee You Can Learn o Guarantee Rzmwg/einrg he eg learned the above in 5 orm If you have Answering_ eiy minutes you should learn the whole sys- s/no/%mp 4 tem in less than 5 hours; after which you develop speed with ordinary practice. $5,000 a e Co///ng s/yno/ Operolors se/ reward on superiority of K. I. Shorthand. /oinp Take down rs speeches, talks, Typical Circuits of Bell Telephone Exchange, Showing Position of Repeating and Retardation telephone+' lttessages, Coils, Lamp Call Signals, Et Cetera. order$;4ermons; make ' ÿoûi memo- Keep producing the phenomenon of selective re- as to the external and internal wiring of randa quickly. further when these the Bell Telephone System. private diary. Im- flection. \ \'e know that efficiency. 1. It would be for to préVe your natural periods of vibration reside in the A. impossible us Golden oppor- infra -red the vibrating system is no longer give you full details, and especially a com- for an electron but a molecule. Now a mole- plete wiring diagram, of the Bell Tele- tunities now cule is generally neutral as opposed to an phone System in this column. those who learn electron, which is negative electricity. However, we are herewith giving you part shorthand. Prefer- ence is 'given in em- How then can the vibration of a neutral of the circuit as used in the central ex- Prepare for gorernment molecule reflect light since reflection is due change. It shows clearly how the various work ployment to those to the radiation produced by vibrating elec- repeating and retardation coils are used. who use it. trons? Are we to suppose that neutral K. I. SHORTHAND COURSE molecules can radiate energy when in vi- TELEPHONE RELAYS. entitles you to free correspondence tuition bratory motion, or are we to suppose the (902.) J. H. Wood, Iowa, asks: to improve work in your own occupation. molecules cease to be neutral when vi- Q. 1. What is the state of the work noiv brating? done by the telephone relay? FREE BROCHURE TO YOU A. 3. (a) \Ve would recommend Dr. A. 1. The Bell Telephone Co. is now Let us send you FREE, our new bro- Nikola Teslá s book entitled "Experiments using a very successful form of telephone chure of the wonderfully easy -to -learn K. I. with Currents of High Frequency and Po- relay of the Audion type on their long Shorthand. The total cost, including special tential" which contains much valuable in- distance lines, between the eastern and will be only five dollars If you from New correspondence, formation on unipolar lamps lighted by western coasts. talk under 30 days' money -back offer. Fill out high frequency currents. etc. For infor- York to San Francisco, your "voice" passes or copy coupon below and mail to us mation concerning the Fleming valve and thru one of these Audion relays. promptly. A postcard will do- Mention other valves of similar type, we would rec- Also the "Brown" Microphonic Relay has Electrical Experimenter. Address: ommend that you consult any of the mod- been used quite successfully in England ern hand -books on Radio -telegraphy, infor several years in telephone and other cluding the excellent work of Dr. J. A. work. There have been many patents taken KING INSTITUTE few 8 So. Wabash Ave. 154 Fast 32d St. Fleming, which we can supply at $10 net. out in the past years on electro -mag- CHICAGO or NEW YORK An exhaustive article describing the exact netic forms of telephone relay, and if you mode of operation of the Audion appeared are intending to carry out research work Send FREE BROCHURE EA -loo of K. I. Short- in the August, 1916, issue of THE ELEC- on this device, we would strongly suggest hand with guarantee to me, postpaid. TRICAL EXPERIMENTER. page 251, and which that you have a patent attorney make is one of the most authoritative that has search of the patent office records, and Name ...... appeared on the subject. the article having furnish you with copies of all of these dddres, been past upon by Dr. de Forest and sev- patents taken out in recent years.

Yon benefit by mentioning the "Electrical Experimenter" when writing to odtntirera

www.americanradiohistory.com 788 ELECTRICAL EXPERIMENTER March, 1918

COST OF RUNNING ELECTRIC LAMP. (903.1 G. H. B., New York, inquiries: P130214..., Q. 1. How many kilowatt -hours will a .23 watt, 110 volt, Mazda lamp consume, burning 31 days continuously and what will it cost to operate? CÌ'trtQtes A. 1. A 25 watt, 110 volt Mazda tung- Tells about the many chancee for melt with electrical .fijFLDCAL., training. Shows how you can master a paying profession sten lamp, burning continuously for 31 while you hold your present job. Telle how other men have days will consume 18.6 K. W. hours of trained in spare time and are now making attractive, steady electrical energy and at 10c per K. W. H. incomes. The book is free. Also a Personal Analysis which will show just what qualifications you have. Send now. your bill for this lamp would be $1.86. This is computed as follows : The 25 watt lamp would consume .025 K. W. H. per A hour (25 _ 1.000, as there are 1.000 watts e Successful per hour to 1 K W. H.) ; then .025 X 24 X 31 - 18.6 K. W. H. in 31 days. At 10e per K. W. H. the bill figures out at $1.86 Electrician (18.6 X $0.10 = $1.86). Electricity is a great and fascinating calling. It is one of the great professions of the future. What Edison has done shows its PROCEEDINGS OF AMERICAN possibilities. Think of Dr. Steinmetz. once an immigrant without INSTITUTE OF ELECTRICAL friends or money, now consulting engineer for General Electric ENGINEERS. Co. And Prof. Pupin who got $250,000 for one electrical invention. All Partial List of cannot rise like these men, but any man who knows electricity thor- 1904.1 1. E Cartinill. \V. Va.. wants to oughly has no limit upon him. The field is so large that is a de- there knots : Subjects mand for trained men as inventors, engineers and experts in a score of Fundamental Principles of different branches. Good wages made in ordinary electrical work. Q. 1. Where he can procure the Ameri- Electricity and Magg etism, Large salaries paid to expert electrical engineers-and the chance to go Into the can Institute of Electrical Dynamos, Motors Lighting electrical contracting business. Get your training now. Here is the opportunity. Engineers' pro- Circuits, Power Circuits. Bell ceedings. Circuits and Wiring. Automo- bile Circuits. Wiring Buildings, A. 1. You may procure copies of the Electrical Signs. Burglar Alarms. Ignition Systems, Mr Complete Course By proceedings of the American Institute of ten. Storage Batteries. Lamps, Electrical Engineers by writing to the Sec- Equalizcrs,Cont rollers.Switch- boards.Telegraphe.Telephones, Mail on Easy Terms retary. Nlr. F. L. Hutchinson, d/o the In- Teleutographs. x- Rays,Trans- stitute, 33 \ \'est 39th Street, New York form era, Calculating Wire This important subject made clear. Personal instruction under Sizes, Electrical Heating In- Prof. Albert Wood Wicks, E. E.. one of America's well known electrical City, and the monthly Proceedings are Rabat ion of Electrical Systems, experts. Learn while holding your present job. Earn money before you $1 copy. Electrical Testing. Illuminating finish the course. No advanced education required. The instruction worth a Engineering. Maintenance of starts with first simple principles and take you through our course. Prepares you Electrical Apparatus. one.. rte. to start right. Tali, this sours up now. Study nt home in Spare time. PHOTO -ELECTRIC CELLS. (905.1 T. T. Gentry. Lexington. Ky., Send for Book and Personal Analysis asks: Don't put this off. It costs nothing to get this information and surely it will show you the way to a better future. Write for the Book and Personal Analysis now so you can find out what qualifications you have. Today. WICKS ELECTRICAL INSTITUTE [igerovs Si W. Randolph Street Dept. 302 Chicano. Illinois

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sort dhZerSO/O/ /OO BOG!' p/ole (po/isher0 YOU CAN INSTALL YOUR OWN PLUMBING AT LOW COST Get our Handy Mau ltuok. }very home -owner needs it. Shows new home lmproremaats ' -' a /.JSe (aodized and everything in guaranteed plumbing sod heating supplies exclusively at wholesale prices. Any hea dy m m ceo 1051111 with our free easy Installing plans and instructions with the help of our service. Construction of Photo -Electric Cell. It Gen Our 40 years' experience enna les us torfumish bead tLA anttss. l'UT TO FIT, bathroom crates Electricity When Light Strikes lt. outfits. etc., with new, original. easy instilling features. comb' ning quality. economy. simplicity and ease of installation. Our $500,000 pants behind our guarantee. WRITE TODAY. Q. 1. How to construct a photo -electric THE HARDIN -LAVIN CO., 40 Years at 4541.51 Cottage Grove Ave.. Chicago cell? A. 1. Regarding the construction of light- sensitive copper oxid (photo -electric) THE "LITTLE PET" cells, these are usually constructed of two thin copper plates immersed in a salt water s unquestionably the engine you solution. one of the plates (front one) behave always wanted. Ideal to run ing blackened by oxidation over a gas or small electric power plants, for charging storage batteries, electro- other flame. and the other (back plate) re- plating for the laboratory. for the maining polished. A sensitive galvano- workshop, drive bench lathe, meter can he connected across the two grinder, vw. washing machine. etc. plates, and when light is thrown on the cell, the galvanometer will be deflected. Operates on either gaso- Refer to the September, 1916, issue of - Iene or City gas. this journal, page 316, where extensive Coil built into engine, countershaft and all gears safely housed. Ready to run when you unpack it. only technical data is given on such cells. In battery to be connected. Any speed from too to 1400 R.P.M. can be had instantly, while engine ii running. one type tried out and there described in Step on foot pedal to start engine. Automatic oiling, no grease cups, ao ideal home motor safe and dependable. detail. the voltage produced in strong sun- will last for years. Cost to run t y cents per hour. Engine has a" bore and 2" stroke. Gives over % Il.P. Weight 6o lbs. light was 1 /10 volt and the current about $33.00 Send for fret catalog E. 1 -2.000 ampere. This was with a small Price completeP p ELGIN GAS MOTOR CO., Elgin, Ill, cell having plates but 3 by 4 inches. It was found that if the cell was left short - FOR ACTIVE circuited in the dark while not in use, the SERVICE efficiency of the light reaction would then he greater upon exposure than when left open - $1 circuited while not in use. Upon exposure of the front plate to light the electronic reaction is practically instantaneous. The Dependablerfor a life time. Made right to write right. Long or Short -Red or Black. aAay bustn.maw, or woman. Promotes - efficiency. Uoeeualled for general wriliog. ItUling, ruling and mardfolding. Made of purs electronic flow with light on is from the reinstated rubber with non - corrosive, durable writing point. Lock-Cap prevents leaking. Extra sirs, 8 Inches, plate black only. Complete Pen Proposition rear to the front plate; the current $1.25. Catalog and Antat'i on soonest. J. R. ULLRICH &CO..27 Thomas ST, Nov Tab flow from the front to the rear plate. You benefit by mentioning the "Electrical Experimenter" when uniting to odvertisers.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 789

ARC LIGHTS VS. SERIES INCAN- NEW AUTOMATIC FIRE DE- DESCENT LAMPS. TECTOR. (907.) W. D -, inquires ; This new electric fire detector is a con Q. 1. As to relative charges which pact little device to be used in either dot' YOU MIND should be made for series incandescent ings, factories or warehouses, piers, etc., lamps in place of arc lamps for street give warning, by means of any alarms lighting? WANDERER! A. I. in the first place, we cannot give CONt\s you the exact data desired as we do not 1.NT C tT lrl.\ of alr.d, of a ^ore, Is .1 know the total watts consumed by the fag for m yuur endeavor and no one men- can wcc s,fully cotoodOrate and apply 600 C. 1'. 4.4 ampere series arc lamp himself if his body Is not in perfect health. tioned. The mind enutd redert the ailing condition of Figuring, however. on 70 volts per se- his body and Impair his ability you a of 4.4 II are only 50% of the nun you ought to Le. ries arc lamp and with current If you hare let your r saber gbh away wIthou! cultl- amperes you would obtain a total consump- rating the rr urCea within pm. If you have let your. self run darni physleelly until It a ^ecta you mentally, tion of 308 watts per arc. you liase Giro neglectful of your body r needs you ratio between the 100 watt well know that weal debilitated system affects the The inverse memory. destroys your ambition. makes you unequal series incandescent lamp and the 308 -watt to any 1..4 and compels you to drag along in Ilst- arc lamp is therefore 32.45 per cent, and leee fashion. rate per I will put your efficiency up to the notch where It this percentage of 87.50 (the ought to he; n o atter who tour condition now Ls annum for the arc) gives $28.42 per annum or your position; r l will Itlake tau once more gain a keen, vivid relish for work and I lea.ure and enable as the equivalent rate which should be paid you to have such control of your mind that every lamp, toed thought. Instead of going to aaste. you ra for the 100 watt series incandescent c ash in on. considering the same hase price per k.w. I will male you vital. vigorous snappy. energetir hour. enthusiastic- ambitious; I will Inste you do moo with lees ettort: t will make you feel the tingle , r Speaking in a general way and without Simple Form of Electric Fire rich. red blond flowing in your veins; I will make any of the details governing the Detector Operating Upon the you feel the thrill of your nature and Increase your knowing Principle That Air, When life; I will make you splendidly healthy. Prong. operating conditions of your local electric Heated, Rapidly Expands. virile, phyali ally ble mentally capable. better that the bossy. better in mind -all distressing resist, f r light company, we would advise This Causes the Device to fui folly will to minified and will ' ' series incandescent will prove the least ex- Close an Alarm Circuit. pensive with regard to maintenance as I Will Revitalize, Rebuild 1 oar arc lights. It is our annunciator system to which may be con compared to the it Through a Course of opinion that the method of computing the nected, of a fire in its early stages so that a equivalent rate to be paid by the city for fire extinguishing equipment can be brought incandescent series lamps as above out- into use before the fire passes beyond the lined is not fair in all cases. owing to the first critical few minutes. It gives an alarn Strongfortism fact that the electric light company may in ten to thirty seconds ; automatically ad be operating under much less favorable justing itself to the usual changes of tern It will re,;aln for you the powers you lost. or attain conditions in your city as compared to the perature occurring within the enclosure in for you powert you never operating in the other city. which it is located. One detector will take It wall restore conditions your vitality. It will mike care of 300 to 500 square feet. The device you realize the life that worth 11 ein; QUERY. is thoroly protected against injury by n BAROMETER guard, which is placed over the sensitive (0OS l Guy B. Admire. Missouri. asks: portions. I Guarantee Q. 1. See first experiment at Fig. 1. These detectors may be put in with one right ; a partial vacuum is produced at the or more on a circuit on their own independ- Results top of the tube. Say the atmospheric present system or they may be connected to the ,ure pressing down raises the water in this present call -bell system, or they may be Sa confident am f. the tithe 15 inches. But in the second experi- 1 place myself under obli- connected, by use of an auxiliary fire -alarm gation to or return 2 produce ment there are square inches instead of box, to the present fire alarm service in the your money. I guarantee t give you greater health sr I ; 30 in this one would it raise water inches building. In private installations, the wir- streoeth and nervous eoeryv tube? ing is not influenced by regulations or im- and ambition and durst) 1 guarantee promotion of s A. 1. In reply to your query concern- usual requirements; the ordinary bell wir- healthier functioning of all ing the height of a liquid in a barometer the organs of Four bed ing properly protected against injury is and the action of your bra: tube, would say that this is a function sufficient, as only battery current is used, arid that you will be mor, depends upon the emeleol., more capable. moo. which atmospheric pres- or it may be installed with a complete sys- able to your work. I guar- sure and upon the density of the liquid in tem of annunciators and fire alarm bells, antee has do yourself, more ambition tand'dash`nd spirit lmand the barometer tube, and nòthing to either with or without the wiring under more happiness 1 guarantee you a cleaner. muo whatsoever with the cross-sectional area wholesome and a stronger body and cl brain. I constant supervision. This system may be guarantee to strengthen your heart, your bowels of the tube itself. connected to any manual fire alarm system your stomach, sexual rgaos -all the muscles of your body. internal and external: to Improve your by an auxiliary transmitting fire box. thus cirrulaUoo. your lung capacity and your symmetry making the present system automatic. of figure I guarantee mat you will he refreshed in- vigorated energized and vitalized. Further. I guar The detector consist of a hemispherical antra positively. that II after you have faithfully -' 7/ followed the Course and followed my instructions. air reservoir, the Hat side or top of which and find that no beneficial results have occurred. is formed by a flexible diafram. This that 1 will refund In full to you every cent of money Mal you paid to me your reservoir contains air at atmospheric pres- for Count. see Coupon -1 heck what ailment Interests you - CD sure and when the surrounding atmosphere Mail It tom and I sill send a practical Talk to you about the edisorder It will tint cost you anything rises in temperature quickly, the dome. and will put you on the right road. which is a rapid conductor, becomes heated Rend 6 cents in sumps to ry ter mnlung expenses a,mosx07C and expands the air in it, causing the dia- cod receive me book "INTELLIGENCE IN PHYSI. CAL AND HEALTH CULTURE ". It Is writ:v.' for plesSU f fram to project outwardly and close an your Interest and welfare. zs electrical contact. which acts as a switch closing the circuit of whatever fire alarm LIONEL STRONGFORT e r system it is connected with. To prevent Physical and Health Specialist false alarms being turned in by the natural 465 Park Building Newark. N. J changes of temperature within the enclosure fig 2 fis I in which the detector is located, a com- .ur. Lionel ctr,mofort. .evark. 5, J. pensator is made part of the device. Sir: You most lanceta your book. e1,TELLI,,El Ci Diagram Illustrating Querist's Problem, In /A' PHYSICAL AYH HEALTH CULTURE!' I to Which He Asks If Greater Area at Base o lora 6 ernia on stamp, for moiling f marked Barometer Does Not Cause Greater Heigh NEW RADIO RECORD. .T kefoee the subject , Alta I would ht. o orgasm) of Liquid to Be Supported as Shown. folk. is reported that just recently the Mar- It Colds Neuritis ..Constipation Heertweakness coni wireless plant at New Brunswick, ..Catarrh Neuralgia . Biliousness Poor Circulation sea level the atmospheric pressure will Flat Skin At N. J.. "picked up" a message from the ..Asthm Cheat ..Torpid Liver Disorders support roughly about inches of . Obesity Deformity .. Indigestion Despondency thirty Cavite Raval base, on the Philippine Islands, Headache Insomnia ..Nervousness Round Shoulders mercury or about 34 feet water. ..Thinness Impotency ..Poor Memory Lung Troubles of Manila, a adjoining the city of distance of . Rupture Short W ind.. Rheumatic m Increased Height But Tuckerton comes to the Muscular Flat Feet Vital Lesso Youthful. Error, 10,000 miles. Development A new pocket lamp, which carries its own front with a longer reach than that, the electric generating plant and requires no dry report being that several times this fall and battery renewals, remains lighted as long as winter, messages have been grasped out of Vane. the dynamo is kept in motion by a lever the air that were sent from New Zealand, operated by the thumb. just about the antipodes from us. lade...

Yon bent 6t by toe valine inn the "ñlrrl rira! F.rr r, t sri nt fer" rs hen writing to odterfilere.

www.americanradiohistory.com 790 ELECTRICAL EXPERIMENTER March, 1918 Mooré s Universal Assistant and Complete Mechanic TELEPHONING TELEGRAMS. Comma 10113 Pangs, 500 ESanserims, am oves 1,000.000 Conservation is the watchword of the Isncsnuat Faces, CALCTLanoos, Racal:Me as as telephone com- Mier-see, TRADE Seeasts, FOR hour. Telegraph well grecs Bcsmzssl panies are losing experts by the thousand, to the Government, which 0a STERZINO TALtT. HLTOANrG ANn LOW COMM! 'MU W Pe United States CoaILUL ce VIC LNUUS) Id.N6b60L has urgent need of their services. This has PRICE POSTPAID many branch telegraph office, $Z o...w....twá w resulted in .°ñ :,5,e.r being placed in the hands of persons who ; . ï.F..' are not expert telegraph operators. In 6..u..° many cases the business handled is transmitted to main telegraph offices by telephone, and it is important that the method "" w' of transmitting uncommon words, unusual names, code words, cipher words, unpro- nounceable words and words in foreign languages, when passing initials or when spelling in the customary manner, should so. be standardized; that is to say, the same method of transmitting an unpronounce- able word over a telephone circuit should Wart a.am.. r m *i be the same in all sections of the country. tA ' .. The traffic department of the Western .:4'T.': .p,- °e...t e,°'°.`. Union Telegraph Company has authorized the use of the following method for telephoning difficult words and names, which ofe.m ,aLs ought to he made standard thruout the en- uPto..,Me 8.0 e,.rs tire service: . First. pronounce each letter ; then, follow dab M° ne °se..í W^9f with the corresponding identifying word given in the list below. and as illustrated in the example: ,sTml Woes., M1.14 WAY, et . lent IONNSON vSMITH & CO.. Dept. 925541W. Lake St.. CHICPGo A for Adams N for New York B for Boston O for Ocean MAGNETIC C for Chicago P for Peter RECTIFIER BOOSTER D for Denver Q for Queen Patented F -F BATTERY E for Edward R for Robert April tS 1916 Full Wave A. C. Rectifier F for Frank S for Sugar BE YOUR OWN SERVICE STATION G for George T for Thomas H for Henry U for Union Use For Public or Private I for Ida for Victor The Booster ceo be carried to the battery wherever It Is located and is ready to work when the attachment plug is l for John W for William circuit. It K for King X for X Ray efficient and satlet(aewOry meapowers for harging type, of storage batteries where only alternating current la available. L for Lincoln Y for Young We furnish complete portable Charging Rheostat mth am- :tl for Mary for Zero meter and current reculsor for service on D. C. circuits. Z EXAMPLE: If the name "B. C. Dvorak" $24 Complete, and up is to be transmitted, telephone employes F. U. B. Cleveland shall pronounce the name and then say "B THE FRANCE MANUFACTURING CO., Cleveland, Obi., for Boston" and pause, "C for Chicago" Ask your dealer or write Tor Bulletin No. 12 and pause, "D for Denver," "V for Victor," "O for Ocean," "R for Robert," "A for Adams," "K for King." il a Ó l U III and Radioactive Substances FOR EXPERIMENTERS MARCONI PRAISES AMERICA. Carnotite (Radium Mineral) The American Pitchblende found in Colorado, Senator Guglielmo Marconi, who has from which Radium is extracted. been appointed head of the Italian perman- A generous piece, enough to conduct experiments, such as affecting photographic ent mission in America, made the follow- plates thru opaque material (similar to X -Ray pictures), first made by Sir W. Crookes and Mme. Curie, is furnished in neat wooden box. ing remarks recently in addressing the Price of one specimen of Carnotite as described above, sent prepaid 50.25 Carnotite Italian senate on Italo- American relations: Sensitive, prepared Photographic film (X -Ray work Elm) to be used for above "The Italian mission to the United States experiments furnished for $0.10 each extra. Brilliant again realized during its journey the great 1.iafbtUUI- Radioactive Salts, containing one microgram pure Radium Very powerful! friendship and sympathy existing there for in the dark! white luminescence by us and the great assistance the United 10 Milligram of this most carefully prepared Radioactive Salts, sealed in glass tube (protected a metal container), with which every Radium experiment can he conducted. arc furnished States is ready to give us. Price of one tube of Radium Salts as described, sent prepaid 51.00 "The friendly feeling and concrete meas- The contents of this tube can he mixed with special sulphides to form real Radium paint Small bottle of Special Sulphide with liquid adhesive, prepaid SO.Ss ures adopted by the American people in Send for one of these preparations today. stamps or coin accepted. favor of Italy deserve our entire gratitude. SIDNEY SPECIALTY CO. 233 S. FULTON ST. NEW YORK CITY We must consider the spontaneous Ameri- can intervention in the war with special satisfaction." Sterling Electric Heating Pad This emotional pad bobs wake tee elerrrlt.t baee.ate. refuels, always reedy. CALIF. ELECTRIC PLANTS TO It In a weleeme mnocosaor to that dlaerreeeble eleaaca. the oil. beavy. COMBINE. dumay, hot water bag whirl) needs constant refilling. may barb r dl.- charge welding water and whin)" 'coola or Just e comfort comm. Representatives of electric light, heat and nts Sterling pad wine aulak friends by Its good work In all ailing OodlMOns beaeeted by the contlouoae application of beat. such ae morales. toothache power plants serving 38 counties in north- crone. chille. grippe. pneumonia. leaomata, lnlleo. -atlas. backache neu- ern and central California have agreed to ralgia rheumatism. poor circulation. and mtarular Millen.. from foot to head and from babyhoM to old age. allow their electric generating plants, both It may be need anywhere at any time la the borne. hotel er hospitaL hydro- electric and steam, to be operated This Sterling pad is safe. aonot overheat and la made doubly dang -proof by two most clever automatic thermoanb Independent of ma heating Impel. under one head, it was announced recently. Yea can pay more but you cannot buy more In Beating pall yLB, P. M. Downing, chief engineer of the guaranteed. Free Literature end Special Introductory Offer. electrical department of the Pacific Gas and Agent. Wanted In All OW. Territory. Electric company. it was announced, has THE STERLING ELECTRICAL CORPORATION, Mob Avow. Co. Reif 2kb Sued. amber], Ohl., O. S. A been selected to have full charge of all of world. Branched to all part. of the the plants with authority to carry out their efficient operation with rigid economy of fuel oil. and to cease the operation of as sl Marko Storage Batteries many of the steam plants as may be found compatible with proper service. This plan is to be carried into force and for all purposes where a high grade storage battery is required effect at once, and to continue for the dura- \ 'ß,*n% tion of the war and during such further PAUL M. MARKO & CO.. 1191 Redford Ave., Brooklyn time as would be deemed in the best inter- T M,rt Quality 1 N. Y. Depot. 974 8th Ave., N. Y. City ests of the public. You benefit by mentioning the "Electrical Experimenter" when writing to ad: Misers.

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 791 SUBSTITUTE FOR THE LE- CLANCHE CELL. According to the Bulletin de la Societ d' Lucaurogeutent pour 1'1ndustrie Nation- ale. Prof. Féry describes a new type of wet primary cell that he has elaborated. The Leclanché cell, depolarized by manganese ELECTRICAL MACHINERY, by Terrell dioxid, is the most common type at the Croft. First Edition, cloth bound, 318 present day. Prof. Féry conceived the pages; numerous illustrations; 51/2 x 8j idea of doing without manganese dioxid and inches. Price $2.00. Publisht by Mc- depolarizing the cell with the oxygen of the Graw -Hill Book Co., New York, 1917. Hitherto, attempts in this direction had air. Another work from success owing to the zinc this author of practical not met with much electrical books and one that will be thoroly ap- electrode being vertical in position, giving preciated by the practical Ivan. The many chap- rise to certain disadvantages. ters and sub-divisions cover all phases of electrical machinery that one and use the constantly conies in contact To overcome these defects, with. Practical applications and theories bave air as the depolarizer, Prof Féry has given been arranged side by side so that the student, to MONTH as well as the advanced worker, PAY $lOO $150 the zinc electrode the form of a horizontal is able by means U. S GOVERNMENT WANTS of the diagrams and explanations to Send grasp the - Coupon plate placed at the bottom of the cell. The essentials of modern Railway Mall Clerks -City Mall Car electrical practise. A com. rlert Poatofllce Clerks - Clerks Belaw- carbon electrode is vertical, being separated prehensive idea of its scope may be gained from - at Washington. D. C. traeólia iota* from the zinc by a thin sheet of felt or an the following list of chapters: THOUSANDS MEN AND Principles. WOMEN WANTED Dept. M103 Construction and Characteristics of N. Y. ebonite cross piece. Direct -Current Generators and Motors; Manage- Common educaltion suffi- Rochester, Local action in a cell of this type is prac- ment of Direct Current Generators, cient. Send upon That coupe, filed out as Starting and ImmMlately. We directed. entitles the sender to tically, eliminated. and the quantity of zinc Controlling Devices for D. C. Motors; Troubles coach candi- 11) free sampleesammatioa ques- and Testing of D. Generators a tree boa. is 1.24 grammes per ampere -hour. C. and Motors; dates free. tions: (2) copy of ,err dissolved Principles, Construction and Characteristics of .:Coremment l'oaiUoa. and m,:w to Get The voltage on open circuit is 1.18. Alternating-Current Generators; Management of Theni ; (3) free Het of posttlona now pen. Generators; Induction and Repulsion Motors; and III to cemaderatn,n r.r Free Cosctuag Syn. for the eeam,natlon here check. I chronous Motors and Condensers; Management of CO U PON' SUNDAYS AND THURSDAYS SET and Starting and Controlling Devices for A. C. ..Railway Mall Clerk . - - - 550010 51800 Motors; Troubles and Testing of A. C. Generators .. Posta hie Clerk 5800 l0 51200 and Motors. ..Pc,tafllce Canter 5800 to $1200 ASIDE AS "LIGHTLESS - . - A truly motor and generator hook, . Rural Mall Carrier $500 to $1200 and one Bookkeeper 51000 to $1800 NIGHTS." which will find a ready welcome by all electrical 15800 men. Internal Revenues 500 to $1800 To further conserve coal and other fuels, .Stenographer 151100 to $1500. ..Clerk In the Departments at the United States Fuel Administration, PERPETUAL MOTION, by I'ercy Ver- Washington - ($1100 to 515001 its orders the amending former permitting ance. Cloth bound ; 360 pages ; illus- Rave operation of signs restricted nightly electric trated; 51/4 x 8 inches. Price $2.00. Pub - Addnse _51 10 and displays, has now put into effect a lisht by Enlightment Specialty Co., St. use Ibis before you lose n. Write plainly. schedule of "lightless nights" on Sunday Louis, Mo. and Thursday of each week. Under the -new order, it is forbidden to A very excellent work on a much discust sub- GROUND ALMONDS ?1' {,'' ject. For centuries the struggle for the means SmOeinaerr Prónhe -Carle Grown Fran seed q[ ' consume coal, oil, gas or other fuel for of self-motive power has progrest and yet today t....i. E',;. "< n ,r ¡dot. illuminating or displaying advertisements, in the Twentieth Century we are as far as ever .. i watt away from the solution. y 1 i Le notices, announctmcnts or signs designat- ,rot hlog The numerous chapters cover a wide range, ing the location of an office or place of busi- giving data on most of the known attempts at ness, or the nature of any business, for elec- perpetual motion. The vast history of the sub- tric searchlights, or for external illumina- ject has been boiled down and a comprehensive Plant Weather Plant digest given, on the different methods by which Shoo Fly tion for ornamentation of any building, or various scholars sought the solution to the prob. lights in the interior of stores, offices or lem. Also chapters on why the various devices other places of business when such stores failed Among some of the more important chapters may are not open for business, excepting such be noted the following: Devices intended to operate by means of awls 30.....,t a". dos _,i 1. v+u- n -L¢w.. Oepe. 925. Se- W Lake SI.. Chicago lights as are necessary for the public safety \\'heels and \\'eights; Devices employing Rolling JOHNSON, SMITH A CO.. or as are required by law: nor for excessive Weights and Inclined Planes- Hydraulic and Hydro -Mechanical Devices; Magnetic Devices; street lighting intended for display or ad- Liquid Air as a Means of Perpetual Motion; Radio vertising purposes, whether such lights are and Radio-Active Substances; List of Numerous maintained by the municipality or others. Inventors and Their Devices and a final chapter on whether has the question will ever be answered, Dr. Garfield, Fuel Administrator, also besides discussions and opinions of eminent scien- TREAT YOURSELF requested that, in compliance with the pa- tists on the subject. triotic spirit of the order, householders A book for all interested in Mechanics, and WITH HEALTH GIVING those who have a strong mechanical bent. This shall observe the "lightless nights" by burn- book does not contain any new matter, hut aims ing as few lights in homes as it is possible rather to provide a fairly broad digest of ti. VIOLET RAY to get along with conveniently. principal perpetual motion schemes proposed from time to time in the world's history. It will prove Health Electricity from your light interesting reading for all those interested in the $Ireagthe°fket transrormal Into the subject from the layman's viewpoint, gre,tea healthglring agency WIRES TO RUSSIA ARE SEVERED. the treat- Beauty knows, to sti yet violet ment being non -mathematical. RAy-- nowentle election yet soothing and gentle In anion: 110 rotta Cable and telegraph lines to Russia have without We slightest shock; pleasant been cut, American Minister Morris, at RADIOTELEGRAPHY-War Depart- and perfectly sate. Stockholm, reported on January 29th, and ment. Office of the Chief Signal Officer, Violet Ray the only remaining routes of communication Paper Covered, 6 x 9 inches, 135 pages, RenuLile with Petrograd now are thru Persia and price 30 cents. Publisht by Government High Frequency Generator Vladivostok. The land telegraph lines were Printing Office, Washington, D. C., 1917. severed, .lr. Morris reported, at Haparanda the lowest priced, most and the cables at Viborg. He gave no in- A very handy book which should find a great Traueffective instrument of many friends among radio men. Into this small Sareessfdy dication of the significance. volume has been compiled all the chief points of -thc kind in the world. radio RAramatitm and endorsed by equipment, formulas and calculations such Ntenrif Used as one expects to find only in a more expensive physicians and beauty BIG POWER PLANT AT NIAGARA hook. I,u re- The work starts with the fundamental princi Chr,t Point specialists. \ can IS PROPOSED. ples of electric charges. static fields, currents, Catarrh ceive the benefits in the magnetic fields, etc.. and then branches out into FlrrJerhr privacy of your own Three bills designed to provide for the power circuits, calculations and the functions of ear ni,rarn the various instruments, with many u r;nktr, home, heretofore only construction State a hydro- electric curves and by the of illustrations which are of great help in mastering Skin Di,ra,r, procurable through cost - plant on Goat Island, Niagara Falls, were the art. fallin` Flpir A treat m introduced in the Legislature at Albany, on Considerable space is devoted to hook -ups of all Etc., Etc. standards sets as used by the U. S. Signal Corps, Write for January 16th, by Senator Gibbs of Buffalo. with notes on gasoline motor sets and complete Provision would be made for a bond issue operating instructions. RenuLife Electric Co. Bldg., Detroit, Mich. of $3,000,000 if the measure should be ap- Several chapters dealing with wave meters, tun- 532 Marquette ing, damping and decrement are very thoro, en- proved by the voters at the Fall election. Wanted. Mee and women pre- abling the uninitiated to grasp the calculations of sentative. to d,m. mstrate to doc- As proposed by the bill, the plant would be radin quantities very readily. tort and lnNrtdul.. Earn 850 a RENULIFE operated either under State management or All in all it is a very handy manual, well worth trek up. We glee full lnswttlone. the sum asked for it Get our pmtasitloo. InOLET RAT lease, and would be generat- trifling and should find a by capable of ready demand from "Radio- hugs" as well as pro. GENERATOR ing 500,000 horse power. fessionals. You benefit by nirntio,Iinq the "Electrical Experimenter" :ehen :hiring to adrertirrre.

www.americanradiohistory.com 792 ELECTRICAL EXPERIMENTER March, I 9 I 8

EXAMPLES IN BATTERY ENGINEER - program. Therefore, we cannot look to ING, by Prof. F. E. Austin. Cloth stearfl to solve the power problem. Evi- bound, 5 x 74/4"; pocket size: 90 pages. dently our only' lasting salvation is in water Price 8125. I'uhlisht by the author at power. Hanover. N. H., 1917. "Water power can be divided into two zones: western and eastern. The bulk of Another very good book by Prof. Austin is this the eastern power is located at Niagara latest pocket manual on Battery Engineering. a Usually very little space is devoted to this impor- Falls. potential possibility of perhaps tant subject in electrical text -books and it is only 6,000,000 horse -power, 3,000,000 available touched on lightly. without affecting its scenic grandeur. We The increasing application of primary and story have heard the great exponents of western age cells and the greatly extended adaptations possible in the near future form valid reasons power proclaim that if there is a shortage why battery students and engineers should have of power in the east, come to the west . au adequate knowledge of the principles of "bat where there are some 13,000.000 horse -power tery engineering.' undeveloped at the present time. This The work covers all the working theories and practical applications in a series of lessons cover- power could be developed at a cost to per ing the same in easy and gradual steps. The mit a selling price equivalent to Niagara importance of chemistry is treated on, as iti has power some five or ten years ago. But is much to do with the final success of the materials involved, etc. potter located so far from the industry's Many practical formulas and examples are given center of gravity cheap at any price? for calculating internal resistance, heat losses, "The electrochemical industries at Niag electro- motive- force. amperage, efficiency. etc Various arrangements of battery circuits are also ara Falls consumed practically all of tht given. power developed on the American side (ap It is a good book for all electrical and radio proximately' 250,000 horsepower) plus ap students and is of particular interest now espe- proximately 150,000 horsepower cially as storage batteries are being adopted more imported widely every day to automobiles, aeroplanes, sub. from Canada before the outbreak of the marines and radio equipments. war. Owing to the increased activities on the Canadian side, the Canadian government has found it necessary to exercise certain NOVEL ELECTRIC TARGET. rights which it retained. and a great percentage of the power coming to this coun- To enable a rifleman to see [there his try- from Canada has been cut off. The bullets go an Ohio inventor has designed industries, therefore, at the falls find them- a target which, when hit, extinguishes selves in the predicament of having installed lights in front of it and shows a light from equipment- but no power to operate it. It : BOOK the hack thru the bullet hole. is doubtful if at the present time 70 per cent of the installed equipment at Niagara Falls is under power. In other words, the plants ON AVIATION are not turning out as much today as they THE United States Government has 3,000,000 H. P. AVAILABLE AT were previous to the war. It was found appropriated $166,000,000 for new NIAGARA WOULD necessary in Buffalo, but 20 miles away, to airplanes. Thousands of trained men SAVE COAL. build a steam plant of 120,000 horsepower. Are needed at once -men trained In the Prin- This being a public service corporation. it ciples and Mechanics of Aviation -men who can (Continued from page 753) necessary serve as airplane designers. builders. assemblers, was to produce power regardless repairmen, mechanics, inspectors, contractors a large user of sulfuric acid, increased its of the cost, but when a mobile industry is and instructors. will you heed the call? Our demand fifteen times normal since the be- affected, there is nothing for it to do hut book tells of these opportunities and is sent move and is you free -prepaid. ginning of the war. this happening. 'Where will this important industry ob- "The best hydraulic talent in America ad- Trained Men Needed at Once tain the power necessary to meet this vast vises us. that it is possible to develop at The Curtiss Aeroplane Company expects to In- demand? Electric power enters into the Niagara Falls 3,000,000 horsepower withotn crease its working force from 7.000 to 20.000 men. The Standard Aero Corporation. Plainfield. New Jersey. cost of these products varying from two in the least affecting the scenic grandeur and hundreds of other factories are working night and 60 ferro of the most wonderful cataract in the world day to supply machines. The airplane companies need per cent to per cent. The cost of a half e million wen right now. The demand u tre- silicon, for example, is about 50 per cent By the proper location of submerged dams, mendous. Did you ever stop to consider the wonderful poaaihiliues offered ambitious men In the profession of power. Hence its cost must be kept at a the rapid deterioration of the Horseshoe Aeronautics? This new billion dollar industry will soon minimum. It must be kept at a minimum Falls would be eliminated and the certain take Its place along aide of the automobile Industry. lie a pioneer in because we are in direct competition with suicide of this wonderful cataract stopt. this industry. Tau may be the fu- turn 'Henry Ford" at Aviation. foreign countries where the governments "The crest of the Horseshoe Falls is mov- National Aero insist on a complete development of the ing hack at the rate of seven feet a Institute Coupon year. Send the safer power resources and where real con- The length of in 1842 was 2.030 Dept. 87443 .Tust put your name and ad- the crest Morton Building dry, in the coupon right now structive legislation is used to aid the cause feet and now has increased to 3.020 feet. ts and receive nur tree book of conservation. Conservation by the way Chicago. Illinois about the Science of Aria - The farther back the erosion goes the Gentlemen.- Please lion. We will tell you that is conservation, and not a plank in a more rapid it becomes. At the present rate, send me absolutely free how you can learn at and prepaid your new home the Principles of political platform. the Horseshoe Falls will be completely book the Science of Aviation. Tear out the eliminated in the next two or three genera- Aviation: also particulars to coupon and mad at "There are but two sources of power' your mall wove in the Prin- once- before thle of- First. coal; second, water. Daily we read tions and the will have nothing but a rapids clples of Acial inn and special ter Is withdrawn. to replace same. The installation limited offer a Do n right away headlines complaining of `shortage of fuel.' the of The most optimistic prognosticators tell us the above mentioned dams would then, National acre Institute the mines will disgorge but little over their therefore. accomplish a double benefit; that pear. arasa usual amount this year. Decreased labor is. preserve the beauty of the falls to- Morton Bidding with developing halt of potential Chicago. [litent, supply is not the only cause of the shortage. gether this It is well known that every ton of steel power. Some have asked for the use of requires a ton of coal in its manufacture. water as limited by the Burton treaty, i. e.. The production of steel is without prece- 36.000 cubic feet per second on the Canadian dent. and so its consumption of coal. Our side and 20.000 cubic feet per second on the How to Make Money might' effort should be to prevent addi- American side, but this is simply a drop with an OLIVER tional uses of coal and in fact diminish the in the bucket and would in no way affect the Many boys pay for their own Oliver Type domestic consumption in favor of the steel serious power shortage that now tends to writers by doing work for others. Easy to learn- line for school work -wins better marks. Then industry. Even if it were possible to obtain ruin one of our most promising industries when you grow up typing is a decided advantage. coal at prices permitting steam- electric de- to say nothing of embarrassing our entire We send you an Oliver for five days' free trial - velopments, the apparatus for this purpose manufacturing position. then you pay $3 per month if you keep it. You can earn more than It costs every year. Write to- could not be obtained in less than three to "Engineers have calculated that to develop day for our free trial blank, catalog and full par- four years. The war program of this coun- 3,000,000 horsepower at Niagara Falls would ticulars. Boys everywhere try is such that the total capacity of the save for posterity 100 tons of coal per are profiting by our liberal minute or 52,000,000 tons of coal per year, plan. manufacturers building this class of apparatus has been requisitioned for that length sufficient to change the situation from a VA4.-; it- THE OLIVER of time which may even be extended. The shortage to a surplus in the coal industry - TYPEWRITER COMPANY is Furthermore, it in freight rr,.,;" 673 Oliver Typewriter Bldg. shortage of power menace with us now would assist the Chicago. III. and its solution must be obtained in far car shortage. releasing 62,000 cars tor use Canadian Price, 562.65 less time than that to save its from a des- elsewhere. thereby changing the situation perate serious embarrassment of our war again from a shortage to a surplus." )-ou br.,rtit br nirnfionino the "Elrctrira: lì.rrrrnnrntrl' ulrrn :titÌnv to advertisers.

www.americanradiohistory.com ELECTRICAL EXPERIMENTER 71) > CHEMICAL EXPERIMENTERS!

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No. 2110 Chemical No. 2108 Chemical No. 2112 Erlenmeyer No. 2127 Desiccating No. 2129 Watch Flask $0.30 Flask $0.30 Flask $0.30 Jar $1.30 Glasses $0.15 Reagents and Chemicals No. 2133 Wash Acid Acetic U.S P lb. $0.45 Cupric Sulphate, tech Ili. $0.40 Bottle Acid Hydrochloric (Muriatic).. lb. 0.45 Ether lb. 0.90 $0.85 Acid Nitric ch. pure lb. 11.45 Formaldehyde, tech. ( Formalin) lb. 0.80 Acid Oxalic, tech. y lb. 0.811 Glycerine ch. pure h lb. 0.90 Acid Sulphuric ch. pure lb. 0.45 Hydrogen Peroxide, tech lb. 0.45 Alcohol denatured Ib. 0.55 Iodine. Resublimed oz. 0.75 Alcohol. Wood, refined 95% Iron Chloride (Ferric) lb. 0.45 (Methyl) lb. 0.50 Iron Sulphate, tech lb. 0.4)1 Ammonia, concentr. (Hydroxide) lb. 0.50 Lead Acetate, tech. Ib. 0.80 Ammonium Carbonate- tech lb. 0.45 Lead Nitrate- tech. lb. 0.95 Ammonium Chloride (Sal) tech. lb. 0.50 Litmus Paper, blue book (d 0.10 Barium Chloride, tech lb. 0.70 Litmus Paper, red book ' 0.10 Calcium Chloride lb. 0.25 Manganese Oioxide. tech Ib 0.85 of sixx Calcium Sulphate lb. 0.25 Mercuric Chloride y5 II, 0.65 Crucibles Chloroform U.S P yS lb. 11.90 $0.50 "The Livest Catalog in America ",'i' Our big, new cyclopedia No. 19 is waiting for you. Positively the most complete Wireless and electrical catalog In print today. It contains the greatest chemical experimental assortment of any catalog in print. There are close to 20 containing several hundred chemical pages. No. 2117 . Ipparatus such as Reagent Bottles, Crucibles, Water Rath, Tripods, Blow Pipes, Chemical Scales, Glass Glass Retorts, Chemical Thermometers, Glass Itods, Beaker Funnel Glasses, Test Tubes, Funnels, Thistle Tubes, Desic- S0.20 cating Jars, Wash Bottles. etc., etc. Also a complete line of Chemical Laboratories from $2.00 up to $90.00. Full line of popular chemicals as used by students. 228 Big ('ages, 600 illustrations. 500 instruments and apparatus, etc. Big "Treatise on Wireless Te legraphy." 20 FREE coupons for our 160 -page FREE Wireless Course in 20 lessons. FItEE Cyclo- pedia No. 19 measures 7x51,1". Weight y5 lb. Beau tiful stilt covers. "The Livest Catalog in America" Now before you turn this page write your name \o. 2148 and address on coupon below, cut or tear out, err Reagent close 6 ets. stamps to corer mail charges, and the Bottles, Is yours by return mail. doze No. 2134 Cyclopedia $3.65 Graduate THE ELECTRO IMPORTING CO. $0.85 New dLwÌw Leie,l[11Fr 231 Fulton Street York City

Mercury Metallic, tech. S? lb. $0.95 Potassium Nitrate % lb. 0.65 Nickel Chloride i5 lb. 0.90 Potassium Permanganate oz. 0.60 Potassium Bromide U.S.P. H lb. 1.211 Silver Nitrate cryst. ... oz. 1.25 Hydroxide (caustic) 11.75 Potassium Carbonate. tech. .., 3. lb. 0.75 Sodium lb. Potassium Chlorate, tech. lb. 0.90 Sulphur (Brimstone) lb. (1.25 y y, Potassium Cyanide j5 Ib. 1.10 Stannous Chloride (Tin) lb. 0.75 No. 2171 Spring Zinc (Mossy) Metal j5 lb. 0.80 Potassium Hydroxide (Caustic) 44 lb. 0.7u Pinch -Cock $0.20 The Electro Importing Company, 231 Fulton St., New York City. I inclose borerrltb 6 cens In stamps or coin for No. 2116 rebid) please send me your latent s}'cloPedl Camelot Set of six t- No. 19 eonWntne 22S pases. 600 IUustrauous ami Test Tubes No. 2186 Test Tube diagrams Including Treatise Wirel w Telegraphy. $0.33 Holder $0.20 Cbenuslry Department. and 20 coupons for pur 160 r page Free Wireless Crouse In 20 Imams.

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www.americanradiohistory.com 7q-3 ELECTRICAL EXPERIMENTER March, 1918 PAT e T

Edited by ANCASrEN8tALLIVINE In this Department we publish such matter as Y REGISTERED ATTOR`+EYS those who are in doubt as to certain Patent Advice" cannot be answered by mail free of War InvenfiornsWar>; d benefit of all readers. if the idea is thought to fl 1C -- -'I r -rat itself to tiv rr cent tear. The greatest victories will divulge details, in order to protect the inventor be i..i. I through togn osi.rin, lutabrs. but through the surpris- Should advice be desired by mail a nominal IstnU,;h[ by Illtruu. n. Luie and ri rti OM lie Sotcd for the Nations it in, :Minus. The Gnvemu:er.r Is r ade to espyri mcut milt and ar Inl! Sketches and descriptions must be clear and ex enn.ul -s 'ure,a.'n , s w n-lt w .11 a:d lu winning and ending the war Lancaster ten on. The Special War Bulletin l ;us( oa the Gres will rare you a gond Idea of what Is need..l. We w II send It to on ft 4. of charge. Locate I in wash ü in;. a in close touch with the proper Government Officials wh Shoull Ieya mashed with inceutinns ter Use io War Ume. and we m! Allwine advl y u fully how the disch.vue stmnld he sent. tnr -e I. erasion with an inventor is, First. to help him establish his M!3- In -fire .riding a sketch. drawing or model to any attorney: Second. 283 STARCHED CLOTHES SPRINKLER. to pug a frank on Inn ten tber it will ray to ratent his idea. based up Ouray Bldg., our ertenr're lin ,stein of the patent laws. manufacturers' wants and (203) Mrs. Leslie McNeill, Corpus BOOK facilities: Third, lo obtain for Hm on reasonable terms. a ratent that abso- N'asbioglon lutely rnroon: and. Fourth, advise and assist bin) in making the úlrennon Christi, Texas, has submitted an idea of a & of by nntri stilt D. C. FORM a s. tira'e I roll: sal, territorial grants, obtaining royalty. or water in the Inds- enCcnt n nnfae'nre nt the inren'inn. sprinkler to be used sprinkling EV E All matters are l held strictly ennfidential. and personal services are as- starched clothes. The idea in brief is a RY sured by our Service Guarantee Contract. References: 2,1 National Balk wash mgeal, D. t' :.John 1'. Moth Parking Co.. Cincinnati. Ohio: Hanle sort of portable tank with a spring attach- INVENTOR Satines Dank. Wa,hinctoo. D. t'.: Dusk-II 31..p Co_ l'adncah. Nen. tr. ment when pulled, tilt. which will sprinkle hater Pe'.re disclosing invention to anvnne. sign. witness anti 1 SHOULD derns l in nur fireproof - fe, the form "Evidence of Conception" q from the bottom of the tank. bra/ establish your rights. A completed sample Coro in our A. \ \'hile the idea is feasible, we think USE h ,,t; shows you clearly how to 7roteet roiir itKennon \II ` - } w), free .lust ask for them on a post card or simply mall it is far too complicated for a household .;pen below. utensil of this kind. It seems to us that the , average housewife would not wish to in- 1 ittr.rt' vest any money in a device of this kind COUPON t. . . when an ordinary cup or sprinkling -can can LANCASTER & ALLWI7 E, be 283 Ouray Bldg., Wanitington. D. C. had for much less money. Anything Send nie free boob. "Intentions- Patenting and Promot- that runs to simplicity and low price is ing," Special War Bulletin. and blank forni "Evidence of sure to in out over more complicated Conception." ideas nowadays. Name

Add, -s COMBINATION ELECTRIC LOCK. (204) Henry O. \\fuelfing, Bloomfield. ! EVERY INVENTOR Conn., has submitted to us a very interest- FREE ing on a lock, A flying model aeropl.ne anould bare this boot. "PATKNTS AND idea combination electric par- and all matenats to build .- PAT'1' POSSIBILITTES." It u chock- ticularly for use in preventing automobile your own scala model. `"*'41104.11 full of Ideas and practical whine. telling Free with our great Home what to Invent and where to sell Write thefts. The lock from the outside ap- Course In the Principles ril4111111Nr' for your copy today. IT IS FREE. pears the same as an ordinary safe -lock, of Aviation. Write at once I bate requests for patents upon sound -before this offer Is withdrawn. Leath tha Science of Avia- Inventions of all kinds. Can you help sup- but in place of the usual steel tumblers, tion at Home -under guidance of Experts. Tremendous de- demand/ md for men oho knew aviation. Wonderful future. Pre- plythesery Is Iedl,ldual, precept and .meamnt fiber gears are substituted which must be Oa tie experience,. Evert pedient Is pare now. Write us today. least turned in a certain position in order to NATIONAL AERO INSTITUTE played to secure patent, at nosdpls cost Dept. 7443. Morton Bldg.. CHICAGO R. S. HILL NI Msleelles Bldg. Waslisom. D C close the circuit, the correct locating being done by turning the dial back and forth to certain numbers. A. This is a very good idea, and we are almost certain that nothing like this exists AMERICA NEEDS at the present time; we are convinced that a patent can he procured on this invention. As a precautionary measure, however, we would advise our correspondent to get in J touch with a patent attorney in order to have a search made in the patent office. Submarines, torpedoes, flying machines, machine guns, immense howitzers, the British "tanks, and an untold number of other GAS STOVE. products of American brains, are dominant factors in the Great (205) Joseph F. Tucci, New York, N.Y., War. We are just starting. our -YOUR -ingenuity must lead to Victory has sent in a sketch of a gas stove, the Uncle Sam -the whole civilized N'orld -is seeking ideas that will aid in the principle of which seems to lie in so- called fight. Can't you help with even ONE of tbousands of simple things that will win recognition -perhaps fortune for you? forced draft, also making use of the prin- The need is for inventions of peace, too. Never before was there such a ciple of a Bunsen burner. This stove throws demand for new ideas of all kinds -never before have so many manufacturers the heat out by means of a hood- shaped top, and other patent buyers, written me for good things protected by OWEN which also serves the purpose to throw PATENTS. There is. today, a market for thousands of ideas -including YOURS. Write for my free booklet and see -read for yourself the hundreds the heat forward instead of upward. The of requests recently received. inventor claims that he thus corrects the You incur no obligation by writing me. My advice costs nothing and I faults of present gas stoves. make no charge for an opinion as to patentability of your idea If my A. This device appears quite plausible opinion is favorable I will back it up by a Guarantee Contract which protects you fully. If you want to sell your invention, I will help you, and will on paper, but without having it tried out, advertise it, free of charge, in "INVENTION AND MANUFACTURING." we are at a loss to know whether it will A simple request will bring to you at once, my four free books: -"SUC actually work as described. We would ad- CESSFUL PATENTS." a 72 gage guide telling how to proceed, gives refer- vise our correspondent to have a model ences, etc.; "STEPPING STONES" tells the truth about prizes for inven- made and if it works satisfactorily, to have tions. gives hundreds of hints of inventions wanted, etc ; "PATENT BUYERS" publishes over 400 requests of manufacturers and others who a search made for patentability. want OWEN PATENTS, together with ideas they want: "PATENT PRO. MOTION," tells you bow to sell, why some inventors fail, discusses the value of your idea, etc. DOUBLE ENVELOPE. Write for these books today. I will send you a signed agreement that will protect you before you disclose your invention. (206) Williams E. King, Monesson, Pa., submits a very ingenious and what he calls a double envelope, made from a single piece RICHARD B OWFiNPaen{ Lanlyer of paper. The double envelope is supposed be for in 161 Omen-Bldo Q/ashinoton'D-C. 2276'8 O/oolmol th-B1d-Near York. to used contributions churches 4 and elsewhere without confusion as to the donation. Our correspondent wants to You benefit by n.enrionino the E;rcrrital L.rcerunentrr" Ono tryitino f, aderfiecre

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 795

,wvENT SOMETHiNG Your Ideas May Bring Wealth If Patented. H. GERNSBACK. Always a Demand for Valuable Inventions. Now is the time to a merituriou invention. We are is of interest to inventors and particularly to patent constantly letters from Phases. Regular inquiries addrest to "Patent receivine manufacturer; and investors who are interested charge. Such inquiries are publisht here for the in new devices and specialties that are protected by patents secured Mr. E. Hume Talbert throueh us. and can he turned into ltoncy thrnuch proper handling. be of importance, we make it a rule not to labor has increased a demand for invcntir;ns in all lines of manufacture as far as it is possible to do so. The shortaee of charge of $1.00 is made for each question. and aericulturc, and plicit. Only one side of sheet should be writ- Uncle Sam Wants New Inventions to Help Win the War You should write us today for a free copy of our loo -pace bl,ok 'l low to Obtain a Patent and What to Invent," and should at the same time send u- a sketch. model or photograph with written description of your invention fur our is satE k FREE OPINION AS TO PATENTABILITY know if such a device is of any value, and If your invention is patentable. we will send you our Certificate of Pa rent, tail ly. w hr.I be patented. is evidence of the conception of your insention and may print of value and a,sistance if it could will enable you to file your apphcauon and proceed with. seems to you. Our Credit System A. The idea is very clever and out delay. Patents secured by us arc advcrived, at our expense. in Electrical Experi- quite feasible. We have seen a double menter Magazine. To protect yourself you should write for our ¡roe ho,,k and suhm t envelope before, but not made as described your invent Mn to tot today. by our correspondent. We would for this TALBERT & TALBERT, Patent Lawyers recommend a search in and other reasons .Sue s s to Talbert a Parker the patent office; any patent attorney will 4287 TnlbietWashington,r be glad to conduct such a search at very Building Washington, D. C. low cost.

DYNAMO. Patents (207) Julius Gernot, Dlaurer, N. J., has PATENTS sent us sketches as well as description of a procured by a former Examining THAT PROTECT AND PAY dynamo armature, which he thinks will Official of the U. S. Patent Office, save not alone an enormous amount of Books and Advice Free Norman T. Whitaker. Attorney -at -Law yu waG e roUm energy, but will almost run free, thereby and Mechanical Engineer, 480 Whitaker on HoEeT REuFrE REN S Bt EST producing free energy! His contention Bldg., Washington, D. C. Inquiries invited. WATSON E. COLEMAN, Patent Lawyer seems to lie in the assumption that bringing 624 F. Street, N. W. Washington. D. C. the windings to a certain position on the outside of the armature, no power will be used in so transposing the windings. Our advice is asked. A. Our correspondent labors under a delusion, and his machine will certainly TENTS WANTED not work as he states. It doesn't matter if the winding of the armature is outside COPYRIGHT or inside, if current is produced he most have just so much energy to do it, and Lar1est Patent Firm this energy cannot possibly be cut down. Po0'RI in the World Our correspondent also seems to think that Before sending your invention to any attorney or it is the field coils which absorb the energy, manufart n rer or diselosIng your home ion. write and reason, he suggests some for our tree blank form PRO(tF' UF' t'UNe'EPTI(N for that In order to protect your buention and sr Ure your changes in the field coils as well. This, rights. This should be signed and witnessed and returned to us. together with a model or xkerm and de- however, is not correct either, for the sim- scription of your Invention. and w will give a FItEE ple reason that if you take a magneto which Os INION as to the patentability of the t"nmiti..n. If we report the invention patentable wo will furnish a Certificate has no field coils it does not work any dif- of Patentability. ferent from a dynamo with field windings. This Certificate of Paleetablllly, together with our blank form SPECIAL Proof of Conception will protect the Inventor and serve as proof If the magnetic flux is cut by the windings U. S. Patent OFFER of the Invention until the case ese be pled In the Victor J. Evans. of the armature, so much energy must be t Rlee. supplied to the driving pullet, in order to OBTAINING ASSISTANCE -FOR INVENTORS-Our certificate is of great as- get so many watts. It doesn t matter how sistance to inventors who require financial aid to obtain patents the windings are arranged, and no matter how efficiently they are disposed, the dif- FIVE BOOKS MAILED FREE OUR (See Coupon ßc!otr) ference in the power factor saved is very distribution. to any address. Send for these books -the finest publications ever issued for free small. A PATENT WHAT TO INVENT HOW TO OBTAIN inventions wanted and Our Illustrated elghty.pege Guido Bonk Is a Brink Contains a rduebte list of for inventors and coutalns 100 mecban- suggestions concerning profitable fields of Inventions; of referait" Information regarding prizes offered for Inven- teal movements. illustrated sud drscrihrd Tells bow ate. to Invent for profit. (Ions amounting to ONE ¡MILLION DOLLARS ELECTRIC NON -FREEZING LIST OF PATENT BUYERS DEVICE. Contains requests from manufacturers. mall order houses and promoters for secured by us and suggestions as in New Ideas they wish to rumba... ru.pi,n` gated, charge. We ban recently l we plorn our clients In tit with capital free of (208) J. D. Browder, Jr., Canadian, recelrcd Ocre 300 r,'plesta from manufacturer& Okla., has submitted an electric non- freez- MILLIONS IN TRADE -MARKS ing arrangement, whereby he uses a cer- Shows the value of Trades -Marks and information regard- tain number of thermostats which control Ilan ^s ing unfair competition huuutug.`k,at We advertise Our Clienti' Inventions Fria In a list of Sunday news. a heating element of an automobile radi- and w'orld's i 'rocces. Same lo asdy,w.ec papers, In manutarturers journals In ator. The idea being that as soon as the Copy Pr.. W. sa- You terne and il n' In sec-tiring fated I.. aver (0 sell temperature goes below 32 degrees Fahren- flu, patent is granted ivo assist yen your patent. heit, the heating element keeps the radiator IDEAS from freezing. WANTED NEW A. A very clever idea and seemingly cheap enough as a commercial article to FREE COUPON! be placed upon the market, where we think VICTOR J. E V A N S & CO. it t[ould find'a ready sale; we believe there PATENT ATTORNEYS is a distinct advantage of having a device New York Omres: Plltsbura Officer. Phlledelphtk Omn, 1001 1007 Bldg. 514 Empire B Idg. Ian Chestnut St. of this kind. Nothing like this seems to to Woolworth exist at the present time. We think an Main Offices: 779 Ninth Street, N.W., Washington, D. C. idea of this kind is patentable. Nome Address

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www.americanradiohistory.com ; yt ELECTRICAL EXPERIMENTER March, 1918

THE THIRD LIBERTY LOAN AND Mr. H. Gernsback, and this is shown YOU! schematically at Fig. 4-B. Three porcelain rolls are used in this scheme A, B and C (Continued from page 751) The three rolls are geared to each other by turned into military or naval appliances means of gears secured to the shafts of almost over night The Army and Navy each roll, but which are not shown for the booths helped to tell the story of how elec- sake of clearness. A thin as well as flexible tricity was mobilized for the defense of the sheet of copper or aluminum foil as nation. also a strip of flexible insulation, such as oiled linen or oiled silk is secured to roller With thousands of men and women, for- A at the left. These are also secured to You who would like to In- merly employed in one form or another roller B as shown. and a second strip of vent something - you who of electrical occupation in civil life, trans- flexible metal foil makes connection to mind- - have Inventions In ferring their activities to the Government B and C. When the adjustment you who have been disap rollers pointed In vortr plea for service, it is hardly necessary to point out knob secured to the central roller B is open a patent -write today for a book that will the patriotism that has actuated this class turned, it unrolls the dielectric and one cop- your eyesI My new 90 -page book. The most of workers. As the war plans of the United per electrode from A, and also the second book ever published for free complete patent are developed and as more and more a distribution. A straightforward revelation of States copper electrode from C, while gradual valuable information. Altogether different from places for electricians are made in the Army increasing condenser capacity is produced the usual stuff sent out to Inventors. Free to and the Navy, the men at home are hearing about the perifery of roller B. The arrows von. Send a postcard. the call. in the drawing indicate how the rollers turn For those who are unable to offer their when the central knob attached to B is New Kind of Patent to the to My services to the country as electricians or rotated either right or the left. I entered the increasing or decreasing the capacity in patent field with electrical inventors or engineers, there still Service the idea of giv- remains an opportunity to be patriotic. The consequence. service to Inventors. 1. ing a superior man who is not in service may act as an The diagram at Fig. 4 -C shows how a My policy has won out big. My free book explains my personal auxiliary to the man who is in the Navy or variable air dielectric condenser may have service to inventors. I do not the Army. How can he do this? Simply its capacity increased several fold by fi11iny to as- entrust your interests by becoming a member of that great army its container with oil. One of the best oil - sistants. Fair. square advice an your Ideas. of "Liberty Loan" subscribers which has to use for the purpose is castor oil, which Sketch or Model been growing steadily since last June. has a "K" value of approximately 5. Thus. Send Me Your inten- Send me sketch, photograph or model of your if the variable condenser with air dielectric tion for prompt report. Let me prove to you what The Third Liberty Loan affords a chance s higbclsss patent attorney service really means. for the electrician at home to stand by his has a capacity of .001 m.f., when it has its GEORGE P. KIMMEL, Patent Lawyer container filled with castor oil, its capaciti Oriental Building. Washington, D. C. associate under arms. The loan not only 88-C will buy clothing and food for the man in will be increased to about .005 m.f. This service, but will help to equip the submarine property is made use of considerably in the chasers, the aero plants and the communica- laboratory, either for the purpose of in- "The Book tion systems in which that associate of his creasing the capacity of the condenser or is rendering expert help to the Government. for increasing the resistance between the PATENT-SENSE plates, and thus cutting down brush dis .v. minaa-nwlT LLttitkr the Inventor Do the readers of THE ELECTRICAL Ex- charges and other leakage, where it is de PERIMENTER realize that the Third Liberty sired to use such a condenser in experi KEEPS" Loan will pay for the Radio that binds to- mental Poulsen Arc circuits, etc. Worth more than t:ether the hundreds of units in the Ameri- the A special form of high capacity, small Sell other patent can fleet? Do they understand that aviator who flies over the Boche trenches size rotary variable condenser used by one books combined. of the leading commercial radio companies FREE. and communicates his discoveries to his comrades by wireless is supplied with his in their receiving sets and measuring instruments, as well as wave meters, is shown Write outfit out of the Liberty Loan? His equip - in section at Fig. 5 -A. This variable con- L[ LACEY & LACEY (Continued on page 798) denser has about five times the capacity of 131 Springer Bldg. .,e ALLY an equal size air dielectric condenser, for w1eYo Washlgt.. D. C. Estahlhh.d Itgb the reason that it employs hard rubber as a dielectric instead of air. THE HOW AND WHY OF RADIO The stationary semi -circular plates are Patent Secured or Fee APPARATUS. covered with thin discs of hard rubber as (Continued from page 766) illustrated, and the moving semi -circular Hundreds of in- plates slide in between the hard rubber Returned ventions sold Several other forms of condenser are il- leaves in the usual manner. The reason for yearly. We help market yours lustrated in Fig. 4-A, B and C. That at A the greatly increased capacity of this type without cost. Our new book is is the familiar rolled type of condenser. condenser is to the high specific in- Free. Send model or sketch for of due free opinion. These are formed of one or more dielectric ductivity of hard rubber, which is about 5 A. M. BUCK & CO. layers, made long with respect to their Another interesting form of condenser 215 2.1 Maul Bask Bag, Wssbtatasa, D.C. width, and which are suitably interleaved which has been used both in this country with two or more metal charging leaves; and abroad to some extent, but which must Getup.to -date infloesrwha. TIYe. aoNaT. the whole is then rolled up and tightly be built very accurately to be reliable and ïAéoa .ne sLtranuL hr n.Ina Electricians ss G!. Cas hLaR IltNe colnprest after having been soaked in hot free from accidental short- circuits, is the iarouwmaa ------ao ease lever Murrains and connection. known by first elms ee q.n. for paraffin wax. This gives a high capacity vertical, cylindrical plate condenser illus- d er o ALARMS need Aran 1 el tneALA for ended HELLS. BURGLARGH e,, dru A bound n foras in a small space, and enables a large ca- trated in plan view at Figure 5 -B. As be- ¡andd e:ble tins LIGHTING.121 usin.r< bound n. the eo or bookb re o_' for e more In e on m. m..1.. Send me pacity condenser to be quickly constructed. comes evident the central rotary knob and rem. and i5they don't make YOU more u cost iäem anand I Substantial terminals for such a condenser shaft carries a suitable rigid member to velu bmany furded --ras t afford tu bo' wiinoot the.q erse noaw oast.a1d. send for clreoLare oo other .et. of drawled.. are formed of small copper strips about which is fastened at either end a set of PATENT SPECIALTY COMPANY of an inch wide, which are wrapt in sev- properly spaced, cylindrically curved plates 462 Sanches Street San Francisco, Cal. eral turns of the tin -foil leaf at the end as which, as the knob is turned, intermesh with Fig. 4-A indicates; this junction may be the similarly curved stationary plates, and riveted. Where a fixt tin -foil and waxed thus increase the capacity of the condenser paper condenser is used, and there are a until they are moved thru 90 degrees. The large number of tin -foil tabs to be joined capacity is reduced by turning the knob so together, a very efficient and substantial that the moving plates slide out from with- SendPATEN me your ideal Manufacturers want Detente I connection is afforded by simply punching in the fixt plates. procure. Prompt, conedrousl, personal servloe by noces fol patent Attorney with hlghast references or drilling a hole thru the tabs and passing Hmeet advice and It is often desirable in building wave "The Truth About Patents- Free. a battery terminal screw thru the opening w'.edeard meters and in certain forms of receiving R. Ibn Bldg. formed and placing on either side of the J. KELLY s IA thing, oo, D, C sets to obtain an extra high variable ca- tin tabs a piece copper or brass -foil of A common method of about % inch square. When the nut on pacity. accomplishing this result is indicated at Fig. 5 -C. the screw is tightened up. the tin -foil con- A nections will be clamped firmly, and the con- small or medium size variable condenser Make Your Watches, Clocks, Etc., VC. is connected in series with the circuit, Visible by Night ;";417 ` ä`dit M. m necting wire from the circuit may be fast- hñ te. and in shunt with this variable capacity r. dre . ÿRlw :":°m::;'G LI}ÌÓÜDInnn4 i eipi;ttrniee'r..é: ened between two nuts on the screw or else ï "M,enl. re nn there is placed a group of small fixt con- ,ISL. Jwa. Ott aÌItMTIm.I ...GUT, TNa .aluralln^ NINef. Quito soldered to the screw as desired. nl,aee_.r,w densers of the desired capacities, arranged .w l ihewn. . n"oaeI'.k .awln.ïe iotm N.. of rem -oriter< ImwI boxes. lantso'..n. a w.wr , mte' e Ce t, ;n,"rM .«.n An interesting roller type of variable con- with a multiple- contact switch similar to u eÌ.Lu 'h!ér:"p.'uriUi. " t : Gales âÓS.nCfîpmtglÁaá.aNá..ú° i Cuói.Co.. 925 Mw. eJe.aat cN. W denser was invented some years ago by that shown in Fig. 3 -C or one comprising

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www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER 797 a metal sector as shown at Fig. 5 -C with a series of spring contact fingers. Thus suppose the variable condenser VC has a capacity of .001 m.f., and that each one of the jive fixt capacities shown has a similar m.f. value. It is thus clear that we may :L now obtain any capacity from practically zero up to and including .006 m.f by in- Tae Vreatier5 stages. termediate e.__, ' >. The standard connections for both fixt t on t 11 wean a and variable condensers arc given at Fig. the 40 1;1 6 B. fixt condenser is usually 6 -A and A ÿt:'V, liait1, connected in series with a detector as shown ocean front at Fig. 6 -A, and is sometimes called the it , 1 r, IL. "stopping" condenser. The high resistance telephone receivers used with this circuit in connection with a crystal detector D. are frequently shunted across the fixt capacity as at Fig. 6 -B. Either connection of the Atlantic City's Newest Fire -Proof Hotel telephone receivers serves equally well in a majority of cases, but if the capacity across offers unusual attractions during Autumn and Winter the 'phones is adjustable or variable, it is considered best practise to connect the Seasons. Luxurious lobbies, spacious verandas, restful sun 'phones across it instead of the detector, as parlors and superb music. A palatial residence for those considerable tuning can be done in this way and maximum strength of signal obtained. seeking rest and recreation. Referring to Fig. 6 -B, a standard connection of the variable condenser is across the American and European Plans the loose coupler LC. The secondary of Illustrated literature and terms mailed variable capacity thus shunted across the Garage with accommodations for chauffeurs . secondary- not only permits the closed oscillatory circuit to be adjusted to resonance with the open aerial circuit, but also permits a closeness of adjustment or tuning which the usual secondary inductance switch does not give. In any case the oscillations HOTEL MARTINIQUE set up in the secondary circuit by adjusting BROADWAY, 32D STREET, NEW YORK it to resonance with the aerial oscillatory One Block from Pennsylvania Station. circuit, overflow to the shunt detector Equally Convenient for circuit, where part of the current is recti- Amusements, Shopping or Business. fied by the crystal detector D, indicated in the diagram, and is stored up in the fixt 157 Pleasant Rooms, with Private Bath. condenser. The charge which this fixt con- $2.50 PER DAY. denser accumulates during the time of a 257 Excellent Rooms, with Private Bath, single train or group of oscillations, dis- facing street, southern exposure, charges turn the high resistance telephone $3.00 PER DAY. receivers T, thus causing the diaframs of Also Attractive Rooms from $1.50. the 'phones to vibrate at a rate which corresponds to the spark frequency of the The Restaurant Prices Are Most Moderate. transmitting station. A new use for variable condensers is Y shown at Fig. 6 -C. There are here used in S e THERE'S PP ONE IN /T " the r6le of a capacity coupling between the =AT-=LEARN aerial and closed oscillatory circuits. The HOMÉ TELEGRAPHY-HÓME- diagram shown is that described and illus- =MORSE AND WIRELESS= trated in the latest edition of the "Naval - - Electrician's. Text -Book" by Captain Bul- lard, Volume 1. This arrangement of -I YOURSELF capacity coupling in the place of electro- TEACI in half the usual time. at trifling cost. with the magnetic coupling, which is used in prac- Wonderful Automatic Transmitter. THE OMNICRAPH. tically all other receiving sets, is strongly Sends unlimited Morse or Continental messages. at an expert operator would. commended by the U. S. Navy experts, and any speed. just as is claimed to be equally efficient to any form Adapted by U. S. Gov't. 4 styles. Catslepue iris. of electromagnetic coupling for short wave lengths, and to be very much higher OMNICRAPH MFG. CO. in efficiency for long wave lengths. In 391- Cortlandt St. New York this hook -up, devised by Dr. Louis Cohen, formerly of the Bureau of Standards Radio Laboratory. the primary circuit is tuned to the incoming wave length in the usual STERLING ELECTRIC WATER PURIFIER Bring, Crystal Spring to Peery Home. manner. The secondary coil L -2 and con- Better then the Beet Bottled Water Without Ito Cost. made same Economy-Efficiency-Sere".iciency- Satty. denser C -2 are resonant to the Some arm. epemd as much u $1.300.00 per year "trying" to get good drtnktna weter- wave length. The aerial circuit energy is and fall. Bottled water spoils In 24 boon belna sutde-t to a process of putrefaction becoming transferred from the one circuit to the other .tale and stagnant. STERLING ELECTRIC WATER PURIFIER by means of the two coupling condensers eeuree perpetual supply of aparkllnr. orrtlal. clear. relatable. healthful water at shown and which are secured to a common ungue,Uooed purity Its natural rUon Is Ilk, strong Fortnight. all germ.. are killed by It. unnatural odors shaft, so that they are simultaneously ad- and colon re removed. Imrunues are precipitated and the berdrot weter mide soft It la ,elf- strrlllring but may be rtadlly cleaned justed. These condensers are in no sense For Factory. Theatre. Office. Home. Elsewhere Moor? Saver, sod Health Presenr. Free Literature and Social Introductory Oder. of the word tuning condensers, and do not Agents Wanted In All Oven Territory. vary the adjustments of either primary or THE STERLING ELECTRICAL CORPORATION. Church Ave. Cor. Weal 28th Street. Cleveland, Ohio. U. S A. secondary oscillatory circuits. They are Branches in B pane of the world used for no other purpose than that of transferring electro- statically the energy in the aerial circuit and circulating thru induc- TYPEWRITER SENSATION -1, com- tance L thence to the closed circuit A Buys prising inductance L -2 and variable capac- Month ity C -2, across which is placed an adjust- i00a Visible Writing L C.C Smith able stopping condenser BC, crystal detector Perfect machines only of standard .Ire with keyboard of standard unlearnt rrsnge etet- has Radceparer- Tabulator -tleh eolor ribbon-Ball Rearing construction--every omeeatlna D. and high resistance telephones,T. aaltnem Fire pay.' Fr.. Trial. Fully guaranteed. CWog and epedl mice sent free. (To be continued) H. A. SMITH, 738 -231 North Fifth Avenue. CHICAGO, ILLINOIS l'ou benefit by nicntiorrinp the "Electrical Erprrímrnter" «hen writing to advertisers.

www.americanradiohistory.com 798 ELECTRICAL EXPERIMENTER March, 1918

THE THIRD LIBERTY LOAN AND equipment. The Third Liberty Loan pro- YOU! vides these essentials. Y.) The Electrical Worker (Continued from page 796) Thus the loan becomes the immediate concern of every man and boy in the electrical Needs This Tool For ment must be of the best. He must have industries and in the experimental labora- instruments and dynamos that are better tories. It is no question of finance which Cutting Condenser Plates than those of the German who is up in the has to do solely with the bankers or with air on the same kind of assignment. All the rich investors. Primarily it is a ! out a bank- Ir Zip And you cut this requires money. That is where the from plain ing matter; yes, and it concerns the mobil- condenser plate American at home can co- operate with the ization of billions in credit. But it also is glass with this genuine man who used to work alongside him, and the personal affair of every one in the "Red Devil" Glass Cutter. who now takes his life in his hands to United States. Has manifold uses besides search out the secrets of the enemy. The First Liberty Loan was over-sub- The German scientists who turned their scribed fifty per cent., so that three billions -handy in repairing win- thoughts toward war many years ago, de- were offered where two were asked for by dow and picture frames, vised weapons of destruction which they the Government. The Second Liberty Loan making table tops, lamp- were quick to bring into action in 1914. was for a minimum of three billions, but shades, etc. British and French intellect, which had not more than four and a half billions were been working in the same barbarous chan- subscribed. \ \'hen the Third Liberty Loan GLASS nels as that of Germany, was forced to imi- is opened. what will the answer of the "Red Devil" CUTTERS tate the enemy. It did not take many Nation be? Trade -Rosa months for our Allies to catch on to this Cut more glass with less pres- new and appalling game. By this time they sure and breakage than any have shown Germany how well they have An order has restricted the lighting of stores and restaurants in Berlin to one -fifth other cutters. Used by all learned the lesson she taught them in 1914. The United States has been forced to go to of the degree of illumination permitted up skilled glaziers. the same school. Here it was only a ques- to December, 1916. To be obtained from hardware tion of turning the unrivalled American dealers, or if not, send 10c for genius for industrial invention in the direc sample, style 024. tiotl of war. The nation has adjusted itself to battle conditions and will fight Germany. Gloss cutter booklet free bomb for bomb, gun for gun, mine for Important Notice to Subscribers Smith & Hemenway Co., Inc. mine. 'plane for 'plane, until the enemy lays down his arms and admits that he cannot 107 Coit Street Irvington, N. J. finish what he started out to do. Due to the congestion existing at the present time in all railroad movements, best nation, The intellects of the hitherto also on account of the fact that many train employed in the diverse industries of the NEW BOOK ON clerks have gone to war, there is a con- country, have been called into consultation gestion of mails all over the United States. by the Government. The Army and the will Navy It happen that your magazine may be ROPE SPLICING are getting the advantage of this "con- slow in reaching you, and this delay may Useful Knots; Hitches, Splices, etc. scription of brains," as the assemblage of be from a few Knots Made and WhatThcy Are Used For days up to several weeks. How Dillerent Are inventors at the call of patriotism may be Kindly bear this in mind before sending INDISPEN5.Su LE TO EVERY MECHANIC ANO RIGGER called. The greatest minds may be diverted in a complaint, as the magazine will surely PRICE A most practical handbook giv- business in the and from private laboratory reach you in due time. Only after not tag complete and simple direc- directed toward the mobilization the me- 9!'tlti all the most of having received a certain copy for a 20e tion for making chanical forces of the nation; the most useful knots, hitches, rig - period of three weeks should a complaint ÿ in all the electrical trades zinc, splices. etc. Over skilled workers be sent in. I. illustrations. All may enlist in the Ordnance or the Signal shout wire rope /1 You will confer a favor upon the pub- ; energy may be bent toward at block'. Corps every lishers not to write until this time has ¡rig. Herald tackles. war ; but unless the Third Liberty Loan is etc. 3. t. elapsed, thereby saving them a vast i7ani e. Ut ere at athry to supported by the people as heartily as were erh n rigor ..'o., nare. amount of clerical labor. .1e 20 eewb oostisaid, n the first two, all these efforts will be in vain. JOHNSON WIN VS CO., Up. 525, SI W. Less SI.. Chew Men cannot fight without supplies and Attention Experimenters!! i, LAST A NON- TECHNICAL MAGAZINE DEVOTED TO YOUR VOL. 2, NO. 1. JANUARY 1918 OWN INTEREST. JUST CHUCK FULL OF THINGS ELECTRI- 10 Cents per Copy 51.00 Per Year CAL, CHEMICAL AND SCIENTIFIC, BESIDES ARTICLES FROM THE COLLECTORS WORLD, ABOUT STAMPS, COINS, MINER- THE SCIENTIFIC ALS AND OTHER CURIOUS THINGS, ALL WRITTEN IN A PLAIN INTERESTING MANNER, FULLY ILLUSTRATED. JUST think of getting a "Magazine" containing departments on "General RESEARCH Articles." Under this heading all things of an experimental nature will be discussed. The Dean of the United States College of Chemistry has an article A Non- Technical to appear in this department entitled a "A Course in General Analysis," which is Magazine devoted to alone worth 100 times the subscription price. Money making formulas, interest- the advancement of ing experiments, the latest news from the many Electrical and Chemical Labora- Electrical and Chem- tories, how to make Chemical and Electrical Apparatus, useful things of all kinds ical Research. and description, things you never saw before about Stamps, Coins and Minerals. An "Open Court" to which all subscribers may submit articles of interest to others, ask questions, etc. THIS NUMBER CONTAINS NO \V OUR VERY SPECIAL LIMITED OFFER. TO THOSE THE FIRST OF A SERIES OF FOR ARTICLES ON CHEMICAL WHO SEND IN THEIR SUBSCRIPTION AT ONCE, WE WILL ANALYSIS, WRITTEN ES- SEND YOU THIS SPLENDID MAGAZINE FOR SIX MONTHS PECIALLY FOR THIS MAGA FOR 25c. THINK OF IT, ONLY 25c. COIN. NO STAMPS ACCEPTED. ZINE BY THE DEAN OF REGULAR PRICE $1.00 PER YEAR. ADDRESS ORDERS TO THE UNITED STATES COLLEGE OF CHEMISTRY. Zenith Chemical Laboratories - - Publishers DULUTH, MINNESOTA

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www.americanradiohistory.com March, I918 ELECTRICAL EXPERIMENTER 799

EXPERIMENTAL PHYSICS. affect the plate or film is called the actinic (Continued front page 760) power. Since all colors do not have the same actinic power, ordinary photographs On comparing (a) and (h) in safe "red do not have truc color values. This effect Mesco Telegraph light" no difference will be apparent. One can be remedied by interposing color might hastily come to the wrong conclusion .screens between the object photographed that light has no chemical effect on silver and the plate, thus reducing the sensitivity Practice Set bromid, but if now a few drops of a weak of the more actinic colors. A still better solution of amidol, eikonogen, pyrogallic way is to use orthochronlotic plates. These For Learning Telegraph Codes acid, ortol, or of any other well known are treated with baths of certain dyes which developer are added to each of the test increase the sensitivity of silver bromid for tubes (a) and (b) we find that (b), the light of their own color. These plates, one which has been exposed to the light, however, have the disadavantage of being rapidly precipitates out fine black particles slower than ordinary plates. which gradually sink to the bottom. (See figure 56 (b).) Evidently the light has Experiment 65: -The process of making done something to it. Actually the light photographs in Nature's own colors has caused the silver bromid to give off a slight been a problem of Physics rather than amount of bromin and percipitate out a Chemistry. There are several processes minute quanity of silver. "Nascent silver" now in use for colored photography both (silver just formed) causes the hydrogen for "still" and "moving' pictures, all of in the "developer" to unite with the bromin which depend upon the same physical prin- The Practice Set comprises a regular tele- of the silver bromid and thus leave the in- ciples of color. In lesson 10 we found that graph key, without circuit breaker, a special soluble black silver particles. In the case ordinary white light is composed of violet, high pitch buzzer, one cell Red Seal Dry of the ordinary "dry plate" or "film," silver indigo, blue, green, yellow, orange and red, Battery, and four feet of green silk covered is mixed with gelatine a if we flexible cord. bromid (forming and that mix these colors white light The key and buzzer are mounted on a more sensitive combination than the silver results. As a matter of fact if blue- violet highly finished wood base, and three nickel bromid alone, since the gelatine absorbs red, and green (three primary colors) are plated binding posts are so connected that the set may be used for five different pur- the bromin given off) hence aiding the mixed white light results. poses. liberation of bromin and the deposition of List No. silver. The plates or films after being ex- One may satisfy himself of this fact by Price a 342 Telegraph Practice Set, with Bat- but dividing circular piece of cardboard into tery and posed show no change to the eye when equal Cora $2.70 placed in the developer, wherever there was three parts, painting the segments most light there will be most action, hence with these three colors (see figure 58) and Oisbaabaa Praha Sel I. Mamie' IEe Morn MESCO and Ceeti.eenl Visual mad AeMble Cdr most silver and hence the darkest part of revolving the circular disk rapidly by attaching to a the "negative." Black giving off no small motor. Because of per- objects, sistence of vision the three colors will strike light do not affect the negative and the p ,e negative stays the eye at apparently the same time and the fi e._-) r tv transparent (white). disk will appear white. In the most suc- t_3o This is illustrated by figure 57. If I is cessful of color photograph processes, the ...1- s. '_ - . . photographed the negative tvill appear as in glass plate is covered with an extremely fine n-_ Il. Naturally one must remove the nega- layer of starch grains (almost microscopic .. tive from the developer as soon as a clear in size) some colored red, others green, and . . . - - image is obtained otherwise the entire still others blue -violet, i.e., the primary amount of silver bromid would be decom- colors (see figure 59). The mixture ap- Thin outfit le too only reliable Instrument whleb will posed and a black plate would be obtained. pears to the eye as white. Upon this mix- enable ssudents to Demote proficient operator. to the O. S. Neal Berries. because It Is equipped with Practise enables one to know just when the ture a layer of gelatine and silver bromid buzzer and miniature lamp enabling the tier to "critical point" is reached. The process of is spread. Since each colored starch grant master both the visual and audible signals ,oleklr. "retaining the image" is not yet complete can transmit only its own color of light it LIMN, SR-Radio Set Pills Red Seal Railer, sal Card, 13.60 since if we were now to allow light to strike is evident that the silver bromid behind the negative the entire amount of silver each red grain will be affected only by red Send for the New Edition of would be deposited giving a black negative. light and a similar result is true for the This is eliminated by "fixing" i.e., dissolv- other two colors. In order to form a posi- Our Catalog W28 ing out the silver bromid by "hypo" (sodium tive immediately, the silver is dissolved out It Is pocket elm. renteine 248 i.e... with over I.ON and washing. thus leaving the sil- Illuetratione and describes In plain. Clear language thiosulfate) and the silver bromid decomposed into all about Belle, Push Button', Bettarles. Tailspins. negative with no more silver bromid to be ver. Therefore tvhere light from a red end Telegraph Merlai, Electric Toys. Burgle sag Fire Alarm Centrlsncss. Electric Can Orti.. Eleetrte acted upon by the light. Now our image is particle struck the plate the silver bromid alarm Clocks. Medical Batted.. Motor Beat Moroi. fixt permanently on the plate or film and was changed to silver, and then the silver Electrleally Heated Apparatus. Battery Connecter. Switches. Battery Gauges. Wireless Telegraph ia- can be used for making prints, enlarge- dissolved out. so that the plate is transparent etruments, Ignition Suppilea, ate. ments, lantern slides, etc. and on looking thru it one sees the little same The process of making prints or positives starch grain. i.e., the color as the Send for the Catalog Now object. The same holds true for the other is essentially the saine as that of making at whole plate negatives. The negative is placed flat two colors. On looking the Manhattan Electrical against the sensitized paper (paper with after development and fixing processes simi- Supply Co., Inc. silver bromid and gelatine or albumen) and lar to those of black and white photography, the transmitted light tvi1l fuse the almost New York: Chleage: ST. LOUIS: exposed. Thus light ttill pass thru the 114 B. microscopic spots of color. and one sees the IT Park Place Wells St. 1150 Floe Si- -light part of the negative and not thru the San Ernelwo Office. 904 Maslen St image the in Nature's own colors. black part of the negative in varying de- of object grees, so that after developing the result is In motion picture work the same prin- really a negative of the negative film or ciple (primary colors) is used. The nega- plate. Referring to figure 57 the see that tives are taken alternately (on black and the negative of ll (which is the negative of white film) thru red, green and blue- violet Automatic Repeating Rifle I) is 1 (which is the original) so that our screens, thus getting pictures of the red, prints are exact copies of the original. green and blue- violet parts of the objects 'Fires films. the films, 20 Shots in Experiment Different colors affect sil- on separate On projecting 64:- a screen similar to the disk of figure 58 is ver bromid in unequal Blue One Loading a degree. and vio- revolved in front of the film swnchronons let have a very pronounced affect while red the films in po- This is a regular size and orange have almost It is because with the placing of three none. sition, so that the filni of the red parts automatic revolver. of this fact that the process of loading and Shoots B. B. shots ob- Only unloading the of the objects is projected ¡bru the red tamable anywhere. camera and the process of screen and similarly for the others. By the developing are carried out in red light. To Samcas other rifles and persistence these are thus 20 verify this, photograph various colored ob- of vision blended. guns. Repeats times 25c natural colors. This phase of with cito 10.:ding. Hand- jects or better still a spectrum (see lesson riving the Posted motion pictures is still in the experimental somely finished in gun 10, figure 52). It will be noticed that red and a fortune awaits the one who Metal. No caps or sad necessary-. as it works appears black and blue white and inter- -tage shoots with rapidity and ac- the develops a good method. with a spring and mediates hues shade gradually from white commercial curacy. Simply load with 20 B. It. shot, then especi,illy a method making it possible to to light gray, darker etc., up to t ss the trigger. Nothing to e,plode abso- then gray, motion pictures in artificial light. May - black. a is of take lutely harmless and safe. Remember. it is not If now print made this efforts of the conscien- and negative the red end of the spectrum will he success reward the a mere toy, but the same size shape as a tious workers in this field. REGULAP. AUTOMATIC. .ens cornt.Irte with a round of white and the blue end black with inter- oho: for ONLY 2SC roe:pid mediate gray. The power of a light to (To he continued) incoaN SMiTN a CO., gee, 525. Sr W feat SI.. emcees Von brvehr by ruses tionin9 the `Ffr.,riro! Eryn une ter' r, hit, vinti,,, to adze misers.

www.americanradiohistory.com 800 ELECTRICAL EXPERIMENTER March, I918

VISITING ARLINGTON VIA THE metcrs. In some way or other we started TALO CLUB. to argue about the number of wires in the aerial, and I nearly bent double trying (Continued front page 763) to Í(ÏÌAPR LEADER count them while "Woody" snapt a picture into the receiving room, and while watch - of me. 'Bet the fellows thought I would The Big Power Motor for Boys $ 00 ing the outfit work we saw the chap out- topple over, but luckily my stabilizer was to I A compact, highly effi- side cut the other fellow off and start working and regained normal position cient reversible motor, operate the relay by hand. Afterwards we again. The large aerials were pulled up by perfect in every detail. í// found out that the chap in question had the means of a steam roller and it was done by The reducing gear, care 11l day be tore been on duty receiving and had pulling up about two hundred feet, and then ily adjusted, transforms k-1 taken his message from a boat. to be re- coming back for another hunk. Pieces of the high speed to more t,it,ifi layed later on. and that the fellow who did wire lay around and we all brought back a power slower speed. \ This motor is guaran- r/(`1 the sending at the time, made a mistake, so souvenir. teed by us to he exactly that was the reason for breaking into the The wires from the telegraph companie as represented. transmitting. Some stunt. say ive. and Washington Observatory were con- KNAPP "LEARNELECTRICS" Along about this time "noon" began to nected in the receiving room, for it is, no Complete Electrical & Experimental Laboratory pay us a visit and, of course, great interest doubt, known that the time clock that closes $2.75 was taken in watching how the 100 K.W. the circuit for both Arlington and Key AT ALL LIVE DEALERS set was started up. One operator throws in West, Florida, is in the Observatory and a switch and the ammeter climbs to 300, and operates both stations simultaneously. Be- Inalst an your dealer showing yen the KNAPP line - happens ; then somebody else grabs KNAPP goods are beet. If your dealer eatmet SUPPLY nothing yond this was a large room where there order dlreet. Send for FRIS Illustrated cats hold and at last the outfit gets into working fou,eene dumbed a complete line of Electrical Motors and were going to be kept various styles of re- Novelties ranging in trite (rem 10e rap. order, but it took five minutes to speed up ceiving sets and form a sort of museum say, 42 cm. gun -fire has on the KNAPP and nothing while in one corner was a box full of Aud- ELECTRIC & NOVELTY CO. noise from the spark when the key is prost. ions ; afterward I told "Dickey" that while 51st N. Y. 523 West Street, City One needs cotton in the ears, and then neither one of us would steal money the some, for when you stand ten feet away temptation to walk off with a couple of and attempt to talk, it's a case of yelling Build a Model of t/ i t Curd, s .tt those bulbs was very strong and he cer- Lary Tractor u red in he G. S..lrmy. your head off, and ten to one the other tainly agreed to the fact. It's a funny i chap don't get you. It is claimed that the thing tho when you look right into it and 1 spark can be heard two miles away on a suppose it is born of the training that an quiet night, and one of the operators told Amateur receives, namely, that radio sets us that when he goes to see his girl he need good detectors and also that every never needs his watch to let him know scrap of material must be saved in order to when it is ten o'clock. make new sets. "Woody" wanted to get a picture of the Our time was now getting short, so tak- back of the small switchboard, and as he Pt ing a last look we beat it for the car which Build A owns a Graflex camera, we were afraid could be seen coming that the noise of its going off would in- some distance away, and upon arriving at Model War Aeroplane! form the operator who would, no doubt, the Monument, the motion on the floor was carried and we Instructtionntyou ran bull, w S -foott Model Aeroplane th.atVlook, demand the film, for at that time some !Ike a real rwe mc,grrtpd you own started skyward. "Woody" and "Mac" flr'aa It from publishing company had bought the rights am a mt.beut VernAeroplanes rand honte,' ér. tend far rar walked up while "Dickey" and "yours truly" Drawings and Imtruotiona for the one you want to baud. to take pictures, so there was nothing doing rode, but as it takes five minutes to travel Canist Military Trarmi ^ e writ t Biplane in the line of amateur photography, but he the five hundred feet we had a Bleut M000plane 2 Jr C Car la s Htdroptaoe told me about his desire, and while he beats nice rest Hieupor! Monoplane EACH Corti s Flying Boat and would have gone it back of the board I motion "Mac" and to sleep only at the Tattle Monoplane le tar 31.7.5 Cecil Peoli Racer start the cables that held the car being so "IDEAL'. Aeroplane nutrurtil Outfits, "Dickey" to come over and talk to the op- containing opla. e J nc d to long, the car oscillated up and down a few these raAeroplanes. are .old by loading erator on duty real loud, thereby hoping to T S i goodd and Department S inches and we thought something was go- $4.004. tS7.0a.o Ask your dealer or "IDEAL.' drown out the sound of Woody's "gun," for Aeroplane Constructors Outfit. Send for ing to happen. We could hear "Woody" Free I,iat of Storrs welch sell these outat.. by the time the glass plate drops out of and "Mac" yelling as they climbed round Send 5c Thls Catalogue the way and the shutter film moves over For and round Teer. about Model Aeroplanes and wist rou the negative and three four on their journey upward and col or other things we mutually thought Informati ndten-I S rent, fey t richtea.: happen, bystanders know it because of the that we for once pos- IDEAL AEROPLANE & SUPPLY CO. sest the brains. 76.82 West Broadway, New York various clicks and groans. Everything worked fine except that when developed The top was reached, but Ye Gods! when the picture was no good, as the light was you look down it almost makes you forget bad, altho to use the words of another the Continental Code and "Woody" almost 1 -50 H. P. MOTOR, $4.75 member, "Look at all the fun we had." lost his hat, hauling his head back in again Going outside to watch the antenna for the windows are small, but I grabbed it "spark," which it didn't, we found the fa- and very near lost my own. Postal cards mous aerial switch mounted on two short were written and mailed at the top, but say. poles with a ship's bell attached (see photo getting back to Arlington, one only appre- herewith). 'Guess they ring the bell when ciates the size of the towers when seen from signals come down the lead -in. The switch the Monument, for it looked just like a gi- consists of a carriage moving on two rails gantic spider about to use the Monument for and controlled by wires passing thru holes a toothpick. The view from the top is in the receiving room wall. This gives great and well worth seeing, because it three positions, namely, grounded, trans- gives a clear idea of how Washington is mission and reception, and is really a very laid out and with a little imagination it clever stunt. I almost forgot to say that is easy to think how it feels to be an aviator. before coming outside we inquired if it Upon coming down we started back for the were possible to go up one of the towers, station and on the way "Woody" and "Mac" and the answer we got was to the effect that took in the Museum while "Dickey" hunted if we could get one of the men to go with up the White House and I kept on till.I hit COMPLETE WITH CORD and PLUG us, why go ahead. So far, so good; but Bryant's "eats dispensary" and satisfied my 115 VOLTS A. C. or D. C. when we glimpsed the small stair -way with 5 m.f. condenser, afterward going to the sta- This Is your chance to get a small motor at a hand -rails only six inches high and nothing tion and waiting for the rest of the bunch to low pries. We have only a limited quantity but air surrounding, Oh! Boy! we thought follow. available at this puce. Order yours to day. of Home and Mother. and mutually dropt BODINE ELECTRIC CO. the subject. 2254 W. Ohio St. Chicago, Ill. TWO of the towers are four hundred feet high. and the other six hundred, so you see Attention !I Mr. Reader. It would have been some climb, and besides big. of Are YOU a constant reader of this journal? powerful. permanent; WC all wanted to get back again the same Magnets f about 3 Ibs. Educational, use There 'is no reason why you should not fol. Sent parcel Pont íl.00 each. day, for I guess that it would have taken at be every reason why you should be- least an hour to climb and do it without -but GENERATORS if you not already. is dropping on the way up. come one, are It we tisi, hare a number of high grade Holtzer by reading along certain Cabot Hand Generators which we will diapre There was a small aerial running from only persistent of at bargain priers. Ciro up to 110 volte. A. C. definite channels that YOU really benefit. You can make direct and run by pulley It de- midway the highest pole down to the sta- sired Special price $3.00 each. tion and this was used for six hundred The "E. E." brings a wide variety of sub- WATSON ELECTRIC CO. meter work, as the large antenna has a jects to your library table every month 124 S. Michigan Ave., Chicago natural period of about two thousand which YOU cannot afford to miss. You benefit by mentioning the "Electrical Expeimenter'' when writing to advertisers.

www.americanradiohistory.com March. 1918 ELECTRICAL EXPERIMENTER 801

EXPERIMENTAL CHEMISTRY. Reduction of Sterols. Experimenter's Special Bench Lathe from page 780) (Continued Perhaps the most striking illustration of A Regular lathe, 0o1 toy and then hung in a solution of a of oxid, the reduction of metals by electrolysis is the to be deposited; a strip of salt of the metal preparation of aluminum as it is now car- silver, or nickel sus - the metal -gold, -is ried on at Niagara Falls, where nearly as anode, to keep pended in the solution (1 kilo equals 2.2 lbs. ap- (See Fig. 5,000,000 kilos the bath from deteriorating. prox.) are annually produced by the famous gold or silver the bath usually 106). For Hall process. The principle involved is not Exl'9:RIMME\TI:Rs: This 1e tlpe dolt together (¡raatical lathe especially designed for all contains potassium cyanid (KCN) dissimilar to those described above, the gold kinds of experimental work. with Thu with a little of the salt of silver or greatest difference being in the solvent and lathe you can make almost anything de- a double cyanid scribed Lo this m a:lne. whether It I. (AgCN), etc., forming the kind of electrodes. A large iron box the "Con tructor" Department or is (KCN. AgCN). The current employed a is lined on the sides and bottom with mix- tl.vlar talent!. `io caalle°ñ l to the ,fan tL cardboard tab., furnished either from a dynamo or battery, ture of carbon and coal tar, which forms the ran he wound nicely with wire by means at this lathe. and in voltage according to the metal it ran end.? be ddren by means of sewing machine or and varies cathode ( See Fig. 107). Large carbon ter- I,Y t .11 electric motor. deposited. minals suspended from rods connected with F1eileot tar small wood turnlos. fibre turning. etr In nickel plating Ian a iv made from Meat materials. Sled, seventeen Indies By way of illustration: the electric supply form the anode. The over a11- -,wing 1 inches. 11 looney onter to center. Bed le mchlind 5 volts, gradually decreasing and ceoten accurately: ahlpping weight D 19 we begin with "bath" consists at first of solid cryolit Ilse erica 54.50 ea,h wl th order. the current to I volt; for silver plating 3 (Na.AIF.), or a mixture of cryolit and Sypher Manufacturing Co.. Department Toledo, Ohio volts potential is employed with a strength fluorit (CaF,), which is put in at the bottom C, of 50 amperes per square meter of cathodic and around the terminals. \\'hen the cur- surface; in gold plating the E. M. F. should rent is turned on the resistance to its iPeRAZOR lóal,n.4t not exceed 1 volt and the current strength passage by the cryolit fuses the latter, after Sftk \1NG A PLEASURE 10 amperes per square meter of cathodic which the aluminum oxid (ALO,), specially surface. The time of immersion varies prepared from the mineral bauxit, impure according to the metal to be plated, the AI (OH)., is fed in. It is first dissolved metal deposited, and the thickness of the by the molten cryolit, and then electrolyzed desired deposit. For nickel plating with a into oxygen and the metal aluminum. The battery current, the time is from two to latter seeks the cathode at the bottom of The first Electoral Reyor eight to twelve where, at intervals, it is drawn off; six hours; for silver, from the bath WITH this new Electrical wonder you get the hours; while gold requires but a few min- while the oxygen passes to the anode, some pleasant effect of massage and a share at of it consuming, at the intense heat, part of the same time. This razor Is on the market utes immersion. and we are shippiog all points in the United States Due to the tendency to peel, heavy plating the carbon and burning it to carbon mon- and South America. should be guarded against. Before such oxid and dioxid, which escape. This device cao be used without electricity like the etc., can be ordinary safety razors. but is supposed to be used base metals as zinc, pewter, Many other metals are now reduced by with alternating current. The blade moves 7neo time, plated with nickel or silver. they are given electric processes, as calcium, arsenic, phos- per minute and actually cuts the hair without pulling Price S to.00. a light coating of copper, the object of phorus, and even iron. Calcium was a cabi- which is to secure firm adhesion of the net curiosity a few years ago, listed at Vibrating Electric Razor Co., Omaha, Neb. plating metal. $10.00 a gram; but now, owing to elec- Electrolysis. trolysis, sells at cents per kilo. It is quite the future, iron ELECTRICAL wane men in°e27DU' ' possible that, some time in reseal. the foodamentale of Applied Electricity. Tue nu meFyec-rg19

- and Most electrochemical processes involve ores may be wholly reduced by electricity. . S¡nom.. with n, well yipped .hop, laboratories. le pea Lady electrolysis. the simplest illustration of eon ee.nned to al,e e eowd.wrd oara.7n eletrletl whic'l is the separation of water into its Many of these processes are electro- ENGINEERING thermic, heat to a far greater de- \Vater was stated to be a non- involving n.dinht M.hem.ii^,. sta and C.e I'. elements. tt p gree than usual, electric furnaces being sub - vti,[[ W.,ln electrolyte ; it can, however, be electrolyzed lye r. ottici and .tract,mi i:!r,T: s1Ì ,tituted for the bath described above. The branch,,. Student.. oelb r ct dyne. indirectly for an experiment as follows: a tail w and t efficiency of heat in these furnaces runs as high as 3,500 elec cal machinery. Coon,. with diploma. small amount of sulfuric acid -which is an Complete Moissan was the first, or electrolyte first mixed with the water, to 4.500 degrees. -is at least one of the first, to utilize the process IN ONE YEAR which is then poured into the electrolytic f,,r rosici 7000 m with limited tim. and invent a furnace, about 1590. This first regnt7L apparatus and connected with the source bth Y.r ns Sept 2nD. li[.1.gun on attempt is illustrated in Fig. 108, and is a 260 Avenue. Washington. D. C. which may be two or three Tekoma of electricity, general type of most electric furnaces. It is cells, these being the best for this Daniell about the same thing as an electric arc light A LJ O using a ^1 purpose; or it may be connected, placed horizontally and inclosed. Intense R a current. A motor -generator, with street heat generated between the carbon terminals B D giving a maximum voltage motor generator or electrodes by the passage of a current is A E 15 is sufficient of 15 and an amperage of of made use of to melt, to vaporize, to reduce R q 11,4 R size. The electrolytic tubes should prefer- or to combine substances. Refractory ele- G 3f Cash with order buy. ably be graduated. \\'hen the current is this ments like platinum, gold, copper, silicon A 3 BENCH LATHE turned on it will be noticed that the gases and even D and carbon are fused vaporized. Swing e ln. e In. C. te C. Shlppine WITS Li. collect unequally about twice as much at In this furnace Moissan made minute dia- N Palee Austin 910 W. First E E. Muncie Ind. W the cathode as at the anode. A slight vari- monds from ordinary black carbon, the dia- ation is due to the greater solubility of mond being an allotropic form of carbon lipSMALL ENGINES oxygen than of hydrogen in eater, After lesson on The substance to (see Carbon). Perfected ( ;ssofir.e Engines -t_, 1 nod current a while, with a running the for be acted on, usually in the form of a pow- 115 h.p. -for Farm and Shop use. Pria lighted splint test the gases which escape. der, is put into the central open space be- $10.5O and up. Also Hydrogen collects at the cathode and oxy- tween the terminals, the space closed. and WASHING MACHINES One, gen at the anode. the current introduced. We Ship On Mal. Send lot Booklet end Special Sieverkrapp Engine Co., 1401 191h Street Primarily it is the acid that is electro- Racine, Wit. Starter for Fora Care + Carborundwn. lyzed. The solution first contains HH ions This product, next to the diamond, is the Feldman's "Geyser" and SO, ions. When the current passes. hardest substance known, and was prepared its chemical properties were Electric Water Heater + + by Acheson. but Hot Water HH ions become H: molecules at the investigated by Miilhauser in 1892. It is Instantaneous cathode and rise thru the liquid. The SO. now made by million of kilos (1 kilo equals FELDMAN MFG. CO. ions at the anode become SO, radicals and 2.2 approx.) annually. its manu- pounds, Bldg. New York City break down into SO. and O. The oxygen facture involved a very simple process, a 1514 Times a gas rises as thru the water, the SO. (be- reaction of silica (SiO,) and carbon. the w Your Own Cards, ing the anhydrid of sulfuric acid) unites with both silicon and oxy- Ireula lebel.Ne ik.paper. latter combining PRt . Lamrfal. Ito. \vtth ILO and forms H,SO,, which is again Prias big gen. 1 9 tory 9:U. Save money. Print for others. + -4- 3C Sic 2 CO catalog SiO, + = 1 [THE paresis ITYPF P.Pet. cardan ionized into 11H and SO, ions, to again Carbon monoxid (CO) escapes thru the PRESS CO.. D-47 Marldan, Cent. go thou the same process. Thus the end loose openings and burns, with the charac- products are hydrogen and oxygen, and the blue flame, to carbon dioxid (CO,) water indirectly has been electrolyzed. The teristic The carborundum ÓON acid remains unchanged in quantity but it on reaching the air. BOOK AVIATION (SiC) is left around the core of the ter- [.earn of the great opportunities in this new is really the acid that carries the current. Si ,0.d.c 40.0 induotcv. Thousands of men neetkd minals as a beautiful, crystalin, iridescent Lawn by mein -tree hook et once In the electrovlsís of all salts in solution mamas NU Manflnt, Celt w.WriteN- we %water plays an important part. lustrous, metallic looking substance.

cc hen :rriti,Q t rtircrtisers. Yon benefit to "lenflortind the "Etectriro' rrprnnienter"

www.americanradiohistory.com 802 ELECTRICAL EXPERIMENTER March, 1918

The furnace is about 5 meters long, 2 existence of the Falls, and Congress has PRACTICAL ;T,. meters wide, and 1% meters high, built Doty past a law limiting the use of the water. ELECTRICAL loosely of uncemented fire brick, and is dis- The electric current is carried for great EDUCATION mantled at the end of each run. The car- distances, even running street cars 100 miles bons are S cm. in diameter and 60 cm. long, away. We teach by practical work and approved scientific methods Prac- arranged in two bundles of about 60 carbons Utilizing the energy of falling water -in- tical Applied Electricity in one each. The charge contains 34.2% year. Commercial Engineering In coke. directly the radiant energy of the sun -be- two years and Electrical Engineer- 542%r sand, and 9.9% sawdust, and 1.7% gun at Niagara. is now carried ing In three years. Short Trade on at other Course gives you big advantage If sodium chlorid (common salt), the total places where cataracts have been provided drafted. Part time employment weight amounting to 10 metric tons. The by nature. The enured for srudenta and positions guaranteed to grad- recent utilization of nature's uates. New Term Opens April god. Write for tree conversion takes about 36 hours and pro- forces has enormously stimulated chemical Illustrated catalog. Meotlon age. education and course Interested m. duces about 2 tons. The core consists industries and led to many discoveries of Home Study Course -If you cannot come to us. or do mainly of grafite around which is a layer new chemical processes; for of all agents, not want to give up your present occupation. we will of the crvstallin carborundum. some 45 cm. electricity best lends furnish you by mall at small cost our theoretical course. itself to the generation Will deduct all payments made when ready to eater thick. of other forms of energy. In Canada, our school et Milwaukee. Get full partloul re. Carborundum is used in all sorts of Switzerland, Brazil and other countries, SCHOOL OF ENGINEERING OF MILWAUKEE. abrasive 29.373 Broadway. Milwaukee. Wisconsin. work from the polishing of granite great waterfalls are utilized in this way. It to dentistry, taking the place formerly oc- is even proposed to carry the electric cur- cupied by emery and corundum. Acids have rent from the falls of Zambesi in Africa to no effect on it. Witwatersrand, a distance of 600 miles. Calcium Carbid.-(CaC5) (To be continued) RADIO OPERATORS NEEDED Government Service Merchant Marine A substance which seems liable to revolu- tionize gas lighting is one of the largest Special course for men subject to PRESIDENT'S SPEECH draft. furnace products. Slaked lime (CaO) and TO WORLD coke (C) are mixed and put into an elec- VIA CABLE AND Complete course of instruction under RADIO. tric furnace, the terminals in which are, as expert teachers in shortest possible time. (Continued front rage 742) Classes for Women usual, carbon. A temperature of 3,300 de- Special grees is obtained, at which the lime melts and thence to India and the East Indies. Complete Equipment-Low Ratee -Indi- vidual Instruction -Rapid Progreaa - and the carbon reacts with it, combining Another cable route extends from Durban, Dormitories-Employment Bu revu. with both calcium and oxygen. the latter on the east coast of Africa, to Mauritius START TODAY forming carbon monoxid and carbon dioxid Island, thence to Cocos Island, to Java and Write for Illustrated Booklet. escaping. The calcium carbid is at first the west coast of Australia, landing at liquid at the high temperature, then is ob- Perth. New Zealand received the message Y. M. C. A. RADIO SCHOOL tained in lumps of gray, earthy appearance. via the Vancouver cable route. 145 E. 86th Street, New York, N. Y. CaO 3C = CaC: + CO One of the longest straight, uninterrupted cable routes is that from San Francisco to BEST RADIO SCHOOL IN NEW YORK The process was invented by \Ioissan and also Willson, the having the Philippine Islands, via Honolulu, T. H., carbid been acci- Midway dently discovered in 1894 by Moissan. Island and Guam. BORE HOLES QUICKER Alaska. too, read \\'hen calcium carbid is thrown into water President Wilson's _)and with leas memorable speech, thanks to the cable run- elbow grease. tee it reacts violently with it, liberating the gas ate Extension ning from Seattle to Valdez, via 'T'Er Rushy acetylene, which burns with a brilliant white Sitka. r. Drill Brace. A perfect Over snow -clad mountains corner brace. extensionxtnsion flame familiar to most readers, uniform and valleys the and breast in one tool Distantly ad- message chuck- drill thruout, entirely devoid of the non -luminous leaped along telegraph wires to justed to various lengths and speeds. Chuck bolds round the farthermost telegraph and sutureusre th a n k Often for itself in parts of the ordinary gas flame. city in this part lob. DedrriUsacid bits. Ipays of the world -St. Michael, on Norton Via Insured Parcel Pest CaCs 2H :0 Ca(OH): C0Hr Thousands In use. Said on money -back guarantee. Send + = + Sound. It swept across Norton Sound with check or money order for one TO.OAV. Start NOW to HsC: -L 5 O = H_O + 2 CO same time and trength- they're valuable. the speed of lightning, thanks to the wire- HOWARD R. SMITH. s234 Harrison SL, Nutley. N. 1. Acetylene is much in use for lighting less system operating between St. Michael headlights on automobiles, but is being and Nome. This wireless link, belonging gradually superseded by the electric lights to the U. S. Government, is of considerable LEARN DRAFTSMANSHIP to a very marked degree. It is also used in historic interest, as it was first built by Send for free Test Lesson and valuable information many places for lighting streets and houses, the well -known American radio pioneer, Dr. on Draftsmanship. Learn how you the gas being liberated in small definite Lee de Forest, in the early days of Radio. can master it at home in leisure time. quantities by water trickling on the carbid. Another frigid clime has FREE Easy terms. Unusual opportunities territory that now, due to war. Draftsmen earn $15 It burns with a very smoky flame unless cable connection with the world, but not LESSON to Moo a week. Write today. used in a special burner. Being an endo- shown on the ordinary map, is Iceland. A CHICAGO TECHNICAL COLLEGE thermic compound, acetylene easily explodes telegraph line runs across Iceland and its 34$ "Tech" Chicago Bldg. Chicago when under great pressure, dissociating into cable route is via Shetland Islands, south- its two elements. It is non -poisonous. ward to Scotland. The preparation of caustic soda by elec- Coming back to the Atlantic Ocean we trolysis was taken up in the Lesson on Sodi- find that at present the direct German cables WIRELESS um and Potassium Hydroxid, and little from New York have been cut. These used The Government now urgently needs radio men more need be said here about this process. to land at Emden and via for the raval Reserve, Aviation and Signal ran the Azores. which tiny spots of land, far in Corps. Our Special short code courses, Day CHEMICAL out the or Keening. prepares you quickly for Govern- UTILIZATION OF SUN'S broad Atlantic, serve to RAYS. join together many ment Service. Students admitted any time. of the most important, long distance cables Send for LATEST prospectus. Just out. That these electrochemical and of the western hemisphere, as a EASTERN RADIO INSTITUTE industries, glance at MI! B Boylston St., Boston, Mase. many others that might have been men- the map shows. tioned, have centered near Niagara Falls is It has been said that, after the war, the due to the drop of 150 feet or more of the United States and Canada will have an THE MIDGET SLIDE RULE vast body of water will add. subtract. multiply. di- of the Niagara River. open sesame in establishing trade connec- vide; solre problems involving even For ages all the tremendous energy of this tions with the South American countries and uneven roots and powers. Also glees the logarithms of number. gigantic falls was wasted. A few years ago This presumption has often been based on and the Sines and Cosines. Tan- the idea was conceived of turning a small the mistaken belief that the European coun- gents and Cotangents of all angles. lac operation ts very simple: quick- portion of the water into a canal, a mile or tries would have to send all cable messages LT solves eny mathematical prob- so back the lem. Durably m°deofmetal Adapt- from main falls. making an arti- via New York, and thence to South ., ed for shop and omee use. Pita ficial drop, by excavation in the earth by the America, via the New York direct cable to 1, the Pocket. 3'4 Inches diameter. side of the river. .Machinery was installed, / Price with instructions $1.00 Colon, etc. In this way it was thought that. 1 o money latelt If yo are not .a,. n.d. the \voter conducted vertically downward perchance, the American merchants would Gihss Side Role G, Nde% Mal. thru penstocks, and turbines placed at the get the tips on commercial deals and beat bottom, which the 25 meters of falling water the Europeans to it -or at least give them with its enormous energy set in motion. a run for their money. This is where many toeservetw th TELEGRAPHY This energy is communicated to the surface people deceive themselves, for there is On land or see. io army. nary, telegraph or railroad cempany, by revolving shafts and there used to drive multiple cable service to Pernambuco, S. A., merchant e or aviation service. Course. under super - aiao of ehiel instructors from Marconi Co. cod Western powerful electric dynamos. The water is via Cape Verde Island, to Lisbon and Union Telegraph Co. discharged by a subterranean passage below Cadiz. thence to London. Marseilles, Aden, Landline or Radio Complete at the Falls (See Fig. 109). It was a magnifi- and the Far East; not to mention the other EASTERN DISTRICT Y. M. C. A. cent scheme, the immediate success of which ambitious empires in northern Europe. all Marcy Ave.. near Broadway BROOKLYN was so great that new companies were of which are plentifully supplied with cable Send for folder F formed -so many as to threaten the very and telegraph connections. 5-nu !, nr6t by mrntienino the "F!rtfrital F.r!rrin:rnrrr" whom aviting so adtrrtisrrs.

www.americanradiohistory.com

March, 1918 ELECTRICAL EXPERIMENTER 803

CAN ELECTRICITY DESTROY Ingals and I discust the problem íor Instructive CHARTS GRAVITATION? hours, but could come to no agreement. REE! The National Geological Society had al- in Drugless Healing (Continued from page 743) 2 ready declared the cause to be a volcanic Bee me Doctor or Chiropractic. . Learnn t home. We train you (having practically no mass) rested upon crevasse of prehistoric origin, a layer above by mail or in eke. No advanced education nee.aeary. insulators. They were separated from the which had given way beneath the city and Ourmethod makee everything protective screen by sheets of glass and dropt it to a great depth. I accepted the plain tor now In demand Some oftour were grounded to it by heavy copper wires. Society's solution as the only reasonable 12raduate. report making metal boxes were then charged in one, but ingals scoffed at it. ,000 a year or more. The $3.000 to $5,000 Yaetyr every way that the solid lead spheres had "The Mars fever has gone to your brain," Yea Moran...re scoot! Income. been, but not the slightest change in the I told him in one of our disputes. "Sup- Chi. fa nMtni %:.l ,,,. li position of the suspended bolls could be posing they could have slipt thru the V- .1n,rlrr. wanes ,' ,n.l .á. now to makeSpin: whchentWawa roe aalutmna for re. detected. This would seem to prove con- plane blockade an obviously absurd prop- yon everything. 11.rer- clusively that the "repulsion" and "gravi- osition -why didn't someone see them corn- PREt. a 114 art of h c,Iered An- [NI ....Ws he had ing or And why selenoid Charts Fwd.. tational nullification" effects that going? didn't the ofo f Ñ ry nuaandGonna. ra 1. ^altuw1 Charm. -- charti in all,. TAU Maorlay Mounts produced when the solid large balls were towers indicate their approach? I suppose la the shine., you're been looking autan.. annoN. for-the opportunity your electrically charged, were genuine and you know that the plates in those towers Won sean, O't o today. Jamie. Gaut. .ttcc.ra based undoubtedly on a true interatomic will record anything coming towards the aM(IKYt ewers rr. Mara, a.aa.a. Out in Cwaw, E. electrical reaction, and not upon any form Earth as soon as the sol -ray interference of elcctro- static or electro -magnetic ef- begins -and that's 2,000 miles up. Pro- fects between the large and small masses. fessor Bergerov explained that very clearly s VOICE THROWER with no in Times. vi/oot Learn to throw your voice into a If they had been, the metal boxes, this morning's Surely, you're 7 4. trunk, under the bed, out in the mass, would have served as well as the not going to maintain that they've learned hall or anywhere. ions or FUN solid balls. to reach us without disturbing the sot- rays." 'r fool ng the Teacher, the Janitor, Policeman or Friends. Another interesting experiment was con- "I'm maintaining only one thing," deducted with low frequency alternating cur- clared Ingals, "and that's the utter assininity THE VENTRILO of relying on the security of the past. \Vhat is a little instrument that Statilto rent applied to the large lead spheres. or do I for damned sol the mouth out of sieht. Revs Girls Spring contact brushes were fastened to care your -rays? The can use it. NEVER FAILS! A 32 the wooden blocks supporting the large same minds that discovered them can find page book on Vrneriioriuten spheres as shown in Fig. 4, one brush on a way to circumvent them. Instead of sent with the VENTRI1.fe for either side of the ball. This permitted wasting time trying to prove why the Rorat Nor. Co.. Dept. 65. Sa. Norwalk. CI, sending current thru the ball from one side Martians couldn't have done it, those sci- to the other. First, a direct current of 20 entists had better be devising something to PER HOUR amperes was sent thru the two large prevent their doing it again. And they'd 35 MILES Milt by boy hen Junior p.ea ty- masses, but no effect upon the suspended better be preparing urgently quick, too, for Ir aLed by as Aar boy eau bead tbt. could he Next, an it's my solemn belief those world- murder- ear. Parts very ebeap. Bend >a masses detected. alter- Record cams fer blue print. and prie. oat nating current of 20 amperes was sent thru ing devils are making ready for another ell This or parts nab mea to wild Ms the large masses, see Fig. 4, with the result descent." Car that the gravitational attraction was quickly Ingals was right. Barely eight days after reduced to zero, and not only that but in the complete obliteration of America's third 15 to 20 minutes the small lead spheres largest city, there came hurtling thru the had moved away over one -half as hutch to air the gripping news of the destruction of the opposite dircction.as the distance they Ramillon, the proud capital city of Mercury. RHEt MPG. CO. had bccn attracted originally towards the The need for theorizing was gone. The 156 large masses. Thus gravitation had not Martians had plainly broken thru the ap- TJLEOO, OHIO ~ only been completely nullified, but it was parently impenetrable blockade and were actually reversed. again wantonly on the rampage. But how? we asked ourselves desperately. What un- DUCK'S known force had blood -reddened Mars un- =-.-..0 BIG 300 pp. ELECTRICAL AT WAR WITH THE INVISIBLE. leashed, that could reach across the in- and WIRELESS CATALOG kllled upon receipt of to In ataapa (Continued from page 759) calculable space, unseen and unheard. and, or coin wmcb may be deducted en more omniscient than lightning, select its drat dollar purchase. Catalog ton- I had feeling rains 160 pares or wireless Instru- the eerie of one who be- victims at will? ment. and 140 pages ot electrical holds ait awesome vision in a dream, aware ¡mantles. No bigger or better values The days that followed Ramillon's de- are obtainable elsewhere. ice bare that he is dreaming and unable to rouse struction were like a gruesome nightmare. complete stock of everything listed himself. All sense of reality vanished be- Every city on the allied planets lived on in this cathlog WI releed Order. fore that appalling devastation. The pramtnty tilled. 1 tide the edge of an unseen abyss, cringingly THE WILLIAM B. DUCK CO. was setting in from the bay and the sullen awaiting the next bolt to fall upon it. 230.232 Superior St. Toledo, Ohio waters brought a small wave lapping at On Friday morning, November 10th, as my feet. There was a splotch of rusty London was emerging from the fitful sleep MUSICAL KAZOO MAGIC FLUTE w.aM .tk., Maa. t ,ir sediment on the wavelet which, to my dis- of a terrorized city into the broad, full sun- win Waalerr.Ry Sweet ordered imagination, had the appearance of shine of a new day, a series of short, Taal awl Mlital blood. It might he from some of the in- sharp, ominous explosions were heard in :';':74 Ñ."u.ú.No other .aiw ' nocents beneath the sea, I thought. and the air above the National Gallery. In Punch .nap.aG .egw>,.e`o. M1M drew back shudderingly. sudden alarm, in f"wra i m.¡: dPaik.l those the vicinity gazed e. áMurs{{ .o The worst feature upward. From Y c-..- 15c was that no one had out of a clear sky, a shower ä,: S .Y. annea yÑpatlit survived to tell of the disaster. Camden, of thin, red. metal discs zigzagged fantas- ,.rMropeo tie e.e.a PT.n V C directly across the river, could give no tically to the ground. Evrelleot for vocal or Irlatramencal sr. coherent account of what it had seen. In . The entire district from Oxford Street rr irniNftl frartraglYr.a. M1k4M. fact, it had seen nothing that could explain to the Victoria Station became at once a JOHNSON SMITH & CO. Dept. 925. 5J W. lake SI.. CHICAGO the mystery. At ten o'clock in the morn - frantic bedlam. Stampeded humanity ing-it was Sunday, and the neighboring rushed for shelter, and with palpitating ex- cities were smiling peacefully rip at the pectancy awaited the direful catastrophe. Convert Your Bicycle into a Motor -Cycle sky -a sudden explosion shook the Earth \ \ritlt fascinated horror they watched the We sell you the motor complete to its very heart. Stunned by the shock, bewildering missiles bound and rebound or furnish you with the finished parts from which you can build the residents of Camden were further be- from street to sidewalk and roll clinkingly the motor yourself with few tools. wildered by the shattering glass and the to and fro. We send you the printed Instruc- rush of wind that sent chimneys and roofs Five -ten minutes past. The scarlet mes- tions with blue prints of the drawings for $.25 or crashing to the streets. Those who were sengers had ceased falling, and lay gleam- full particulars for 3 -cent stamp. first able to look about saw a black cloud ing in the bright autumn sun like splotches STEFFEY MFG. CO.. 5025 Brown St., Phil... Pa rising to a great height above Philadelphia. of blood. Here and there some, more bold It hung there for an hour or more, and than the others, stept out of their hiding meanwhile the surge of angry waters could places, compelled by curiosity to examine MAKE YOUR OWN GENERATOR ! be heard rushing in to fill the void. When these strange visitants from out of the no- We hare a complete line of sturdy efficient the air finally cleared, the terror -stricken where. Gradually London drew a sigh of generators and alternators from 100 to 1000 watts. We furnish these complete, or parts fur- people rushed to the river front and their relief. Traffic and life swung again into nished ready to aasemhte with wire and Instruc- hearts sickened within them as they be- motion. Nothing fearful had happened. tions to wind. Send for catalogue. held a troubled ocean rolling over the The metal hail phenomena would soon be ALL AT FACTORY PRICES. region where once their sister city had explained, perhaps, by those whose business BIR6MANN MOTOR MORNS. It33 NIAGARA ST., BOt1AIO, N. Y. been. it was to solve such freakish events.

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www.americanradiohistory.com 804 ELECTRICAL EXPERIMENTER March, 1918

Hardly au hour liad past when London's less we agreed to her demands by noon on feeling of reassurance was cruelly shat- Thursday, that hour would mark the doom SEND. PICTURES tered. The discs, interpreted by university of New York, and our other cities were experts, were found to be messages from to be similarly damned to extinction. Mars. In one brief statement, the imprint On the Saturday evening following Lon- 13V ELECTRICITY on the red circle announced the complete don's destruction, I sat in the study of my destruction of the city by three o'clock apartment overlooking Van Cortlandt Park. that afternoon. A wail of deepest anguish My mind was spent from a whole day's This latest sensation In else -I tdeal advancement -marvel of rose from London's masses and spread like heart -wearying discussion and argument in today. oecesslty of tomorrow. the blackened wings of doom over the the Council. Many of the older men had agords wonderful entertain- whole city as the demoniac portent of the advised submission, but several members ment. Affords instruction In the coming science. You can evil messengers penetrated the minds of. of the Board of Strategy, including myself, send pictures of your friends the people. pleaded for delay. At any moment the keen by electricity over telegraph minds working tirelessly on the problem wires or by wireless. Picture In vain had the watchers in the Selonoid In this advertisement was sent Towers sprung to their sensitive record- might discover the means used by the Mar- and received by this system. ing plates to seek for some indication of tians to reach our Earth undetected. With- Electrical experts and scien- out such knowledge, we all admitted. our tists have declared the Leish- the enemy's presence. The plates were man Electrical Picture Trans- blank. A message, imploring help, was cause was hopeless. mission System Is the marvel flashed over the Earth and at once our Alone in my room the mystery tugged of the age. See article December Issue. strongest forces were hurled to the spot. at my mind again and again. It was PRICE ONLY MS.00 For Complete Set of Two Machine Huge V- planes, bearing tremendous bat- baffling. In despair I looked about for L.J. LEISHMAN COMPANY DepI.T. Ogden, Utah teries; grim little Heliolites (in one of something to relieve the unbearable strain. which I was stationed) with their atomic The reficcto- screen on the east wall caught detonators, and thousands of other craft my eye. It was connected with the leading thronged the air for a distance of five hun- theaters, and I remember thinking cynically dred miles around and above London. how the people could go on playing even But of what avail our formidable arma- tho the end of the world was in sight. ment, when there was no visible enemy Theresa Carmine was singing at the against whom to direct it? We circled Metropolitan, I noticed by the auto- indica- about in close formation so that not even tor. Switching off the lights, I connected a sparrow could have escaped our reflec- the screen transmitter with the Opera tors, but the air was apparently innocent House, opened the audophone, and stretched of any hostile ship. myself comfortably in an arm chair before Meanwhile, the city below was in the grip the screen. of a hellish panic. Those who could take The second act of Madame Butterfly, to the air did so immediately, with never a that imperishable story of hopeless love, thought for their treasures left behind. was nearing its end and Carmine stood Others pushed and struggled like mad- looking towards the bay, waiting patiently dened beasts along the streets to escape for the lover who would never return. The from the doomed city. Bruised and wonderful colors of the screen brought out crushed bodies lay thick along the high- vividly the pathetic droop of the slim figure . way, like worms after a spring rain, and and the room echoed softly to the sobbing their fellow beings trampled on them un- violins and 'cellos of the orchestra. heedingly in those awful moments. HANDY BINDER Unstrung as I was by the events of these for the Electrical Experimenter Unfortunately, the greater part of those anguished two weeks, the pitiful little Holds and preserves 12 issues, each of which who cleared the city streamed out into Es- tragedy touched me deeply. Tears came to can be inserted or removed at will, without sex and Kent, overflowing such places as my eyes and I thought of Ava. I had been tools. will keep your magazines perfectly for Welling. Grayford, Dagenhow, Grays Thur- unable to see her since the night of the all time or just preserve them lace new till Martians you bind them permanently. Made of heavy rock and Gravesend, where the reception in Paris. Probably the next material, extra strongly reinforced had evidently placed contact points for their cataclysm would destroy one of us, I at the back and covered with band -5 detonators. in order to tear up the entire thought, and the other would be left alone. some green cloth, suitably lettered Thames bed and hasten the deluge from like in gold 0 C the little Butterfly, waiting, waiting - Shipping weight 2 lbs. Add sufficient the North Sea. The curtain dropt and the sound of ring- postage, otherwise we will bave to send A few minutes before the appointed hour ing applause came over the audophone. The binder by express. we planes operator at the Metropolitan now turned his Order a Binder Te -day and Preaere Tow Magazines withdrew our army of with as Erpeimeate ?A. G., loc. 233 Fall *. Street Na. Tor many people as we could load on. I bent visu-flector upon the audience. Row upon Book Deportment. k over the glass in the floor of my Heliolite row of exquisitely drest women and men for a last glimpse of London. flashed on the screen. The sight of the An immense throng had gathered on the smiling, chattering, thoughtless throng Embankment, evidently resigned to the jarred on my mood and I was half rising POCKET BOOK cf ELECTRICITY to disconnect the transmitter, when the SPECIAL dreadful fate, and were listening to the WAR EDITION FREE soothing words an man had view of a box directly in the center of the of old who horseshoe Distributed sa soDDiemeot to oar big Handy Hook the mass like brought me to my feet with a daring tempenry gonerom.oe suspension of tt.- assumed leadership of and Iss.. ILta new thing, to erpperiaent with. Also some inspired prophet was evidently direct- cry of surprise. There sat Ava beside her moto. flashlights. Ieva ph Dpums, pmaka. father. mask Dotal.. book,. athböe roods, ebemtsl net, ing their thoughts away from the approach- a pensive smile on her beautiful fishi tls Ities. Haodr Iptratìag. Foe face. ..er. t», m Ama.ie.. er,e o. 7}ea.en. ing terror. Down Cheapside way, other her eyes shining straight into mine! Th. El.etroSet Co.. woo knoten as The view past in a second and I was left The Newman-stern Co., Dept. E. t: Cventana, omo groups, crazed by fear, were tearing and rending each other in insane fury. My gaping at the screen. I had been so en- grost in the Martian I had last impression -one that I still see vividly atrocities that entirely lost track of Venusian com- whenever I close my eyes -is of a large the SAVE 25 %D to 60% number of women and children kneeling mission's program. Undoubtedly this was lightly used the day in New GRAFLEX - KODAKS on the ground in Regents Park, their arms of their arrival York, and Camera. and Lenses of ovary deoceptltn. outstretched piteously to us as we flew by. of course the committee had taken the Equal to new. Str. money. Write now tor members to the opera. Free Bargain Book and Catalog So long had we stayed, loath to depart I r.en. hundreds of m r bwvams , In another minute was up on the plane la htlr used and new earners. end supplies. All while there remained the faintest hope of ods sold on IO days' Free Trial. More, br roof and had pushed my little electric from fond r sued. You take no haven dealing discovering the Martians, that we had only the The with o. We bore been in the ohot¢nphit ham - garage. despondency of my mood re l.6 ream. Write Now reached Oxford when the explosion came. had changed to joyous exhilaration, and I CENTRAL CAMERA CO., Deal ITS 124 S Wabash An, CVeaga Again the dark cloud of destruction spread rose high in the air before turning towards above the Earth, again the swirling waters Watchwork, the Metropolitan. A young moon was high Learn Jewelrywork and rushed into the chasm, and London with in the heavens and New York lays beneath A fine trade commanding good sal- its ten million lives was gone. me. bathed in the glow. Engraving e ary, and your services are always in enchanting Never demand. Address HOROLOGICAL Department. This was the culminating tragedy. Se- had the city looked so beautiful, so en- Bradley Institute, Peoria, III., for our latest catalog cure in her untrammeled power, Mars now trancing; never had it seemed so dear to issued an insolent manifesto. Peace was me. I was conscious of a sudden strong offered us on terms that would make the faith that it would be saved from the BOOK ON AVIATION allied planets mere vassals to her will. If despoilers. Learn of the Vent rptortumtlia in this new we accepted, the destruction of our cities The last act had already begun when I n,O"i.0M,0') indostrr. Tho0sands of men needed. would cease, otherwise Five days' grace I Learn by moil -free Look tel. how. W rit e at once. -. entered the box. Quietly drew a chair MATINAL AElO INSTITUTE. Oyat *7111 ..e.aaida., Cb.n6. were allotted us to make our decision. Un- from the rear of the box and seated my- l'ou brneSt by mentioning tAt "Electrical Experimenter" rthr.t ttriting to adz.ertixrr..

www.americanradiohistory.com March, 1918 ELECTRICAL EXPERIMENTER oll5

self near Ava. Under cuter of the dark- The part l' is a wooden standard, %" x ness I press my lips to her hand. I felt %" X 1V. To it are screwed the bear- N, supporting the drum, ill, by means The master. a thrill go thru her as she recognized me, ings, piece ofwatery and my heart welled up in contentment. of a small put passing tliru it and serving manufacture-adjust- as a shaft, permitting the drum to revolve ed to the eeeond, positioae, tem- Again I raised her hand to my lips. The vruture and isothruniem. En- bells chimed faintly and Ava prcst freely. faxed et factory into your choice mystic of theerpo,site new watchcases. my hand warningly. I leaned hack, silent!) A good drum may be made by simply drinking in the radiance of her presence. passing an ordinary pin thru the center of Idly my mind played with the thought of a cork. He careful that the top of the drum the bells on her wrist. Mysterious bells, i is even with the center of the motor shaft. A( ^rtes /.,r eerA thought dreamily, ringing like our love from Solder a short piece of No. 28 copper Burlington heart to heart, invisible to the world- wire. L. to the end of the link, I. Pas, it The great Burlington Poy at rrate of ¡2.&OO a montmonth. Yoo pget the wretch at With a sudden jerk I sat upright. "Ava!" once around the drum and fasten the cud thesame price even the wholesale jeweler moot per. I whispered. "Come outside with me." to the pin. S. adjusting the length so that Write Today for Free Watch Book there will be no slack when the slider, J, See handsome color Ill ostrationa of all the newest She turned in surprise. designs io watches that you have to choose from. is out as far as the cord, G, permits it Your name and !dress oo a posteard Is smooth. while "At once!" I urged breathlessly. to go. Get this offer it last.. Write today. hand and fol- Barre en Witch ea. 1 7113 t9th & Marshall BM. a1or. Obediently she took my The clastic band, Q (or better, a spiral was deserted lowed me to the foyer. it spring if you can scare one up), is also settees, and I led her to one of the gilded fastened to the pin, S, and the other end my mind tingling with the idea that had fastened to the small screw -eye, R. The Y entered it. tension will have to he adjusted by experi- Delivered FREE a voice, and Mae. in the famous line of "The bells -" I spoke in choked ment after the speedometer is completed. V e RANGER" bicycles, shown lo unable to the eagerness that was ull n he bheig nreew control O is a wooden standard, tapered at the +t tor! colpary gFrehCiga thrilling me. "Let nie have them -I trust top to about IA" in width. Sec Fig. 3. from Chicago to yoles town. In height it should be just sufficient to 30 Days Free Trial on'pw`1 the "I cannot take them off. No one knows 1. ,eleet, actual riding teat barely support the link, sinIn you own town fora full month. how the bracelet is fastened." My excite- grenu A tack, K. similar to those used in mak- ( Do not hur until you get our had communicated itself to her and f q/1 new triol. o8 and low Factory. ment ing cigar boxes, is placed thru the slot nireetTo-Rider terme and she breathed rapidly. "What is it ?" she S HORNS. pedals, in I and driven almost home, but permit i\1.1 nn TIRES singleLAMPS, wheels ana repast asked eagerly. "What have you dis- parts all makes of bicycles at thug 1 to slide easily back and forth without for ?" half usual prices. No one else can covered of binding. This ar- offer aura shams and such terms. I be- the slightest trace I'm not sure yet, but think -I permits the lateral motion of Mfdor SEND NO MONEY but write today over- rangement for the big new Catalog. It's feu. lieve-" A surge of exultation be to the drum, M, and Attorto me so J w communicated whelmed me and i clasped her to thence to the end of the pointer, while wanted EMUD pt. M -107 Chicago that seemed as if our hearts must tightly it preventing I from turning with the motor and I have meet. "Ava!" I cried. "You and twisting off the connecting wire, L. found the secret of the Martian raids!" Build Your Own PHONOGRAPH cut to the right length. "Where!" she gasped. An old hat pin, It's Eos, sEub Our Helt "On your wrist!" I replied triumphantly. makes an ideal pointer. It should be pushed A few hours interesting work SAVE the drum so that when the motor is saves many dollars and Rites In the excitement of the moment, wrought thru you a machine exactly to OVER and tension, Q, is properly ad- suit your ideals we furnish up by the discovery and the closeness of at rest the be at "stop" on the motors. tone arms, rase ma- HALF her own dear self, I kist her. justed, the end will terial. blue prints and full dial, V, which is supported by the stand- instructions. Playa any rec- "Can the bracelet be touched ?" I asked ord. You man make fine pro when we had sobered down. ard. U. Ht building phonographs for X, X' are two small angle irons used your friends. "Of course. Here, give me your hand." Write Today for our Free Blue to firmly fix the standards, P and U, to Print offer. Agent. wanted With her left hand she directed my for our ready bulls Chonteoma base board. The screws in X' should fingers to a place on her arm. To all ap- the CHORAI.EON CO. skin was abso- be long enough to pass entirely dire U and pearances the soft, white 703 Monad Bldg, EOhad, lid. lutely hare and there was nothing to pre- the wooden block, Y, into P, thus fastening together. vent my touching it ; but with my fingers the three pieces firmly barely a half inch away, a hard object inter- Pins should be driven into the dial at Radio Information posed itself. i could feel it encircling her \V, \V to limit the swing of the pointer. - wrist. It was evidently of glass or some The whole should then be screwed to the other crystalline substance. and, to my cau- base board at the proper distance from the Quick ! tions. exploring fingers the surface ap- motor. Hundreds of commissioned and eo- peared broken into innumerable tiny facets. The principle of operation is similar to listed men in the training camps "'Tile bells are inside," Ava explained. that of a governor on a steam engine. now supplement their military in- were, I continued my instruction with the pleasant reading Blindly,- as it As the armature revolves the weights tend of Philip E. Edelman's "EXPERT vestigations with finger tips alert. to overcome the tension, Q, and fly out, MENTAL WIRELESS STATIONS" "Where and how did you get the bell - J, the flange. The big 272 PD. IUUatreted sloth bound thus pulling the slider. toward modern text that covers modern radio bracelet ?' I asked. B. This lateral motion is communicated to Subtort. so that every mother's son gave it to me means Understands. Only 61.50 prepaid. Ser- "A friend of my father the drum, M. anti pointer, T, by of tice dsco11,1 to em jr.' Compaill, . mi years ago. He was always experimenting the link, I, and wire. L. The faster the hgnes1. the P. EDELMAN Pub.. with mirrors and stones. I remember his armature revolves the farther will 1802 Hague Ave.. Si.. Paul. Mlcn saying that some day he would be able to weights fly out, causing the pointer to move wear a coat that would make him invisible." across the dial toward the left. Practical A swift light of understanding illuminated This instrument can be calibrated by the A tics her deep, opal eyes. "That is just what the AV/AT/ON BY .val1L aid of a "stop" or ordinary watch so as Train nt home. iiun Martians are doing!" she exclaimed. per minute" (R.P.M.) dreda of a +,non. open to read "revolutions Get f nodded. "Is that man still alive ?" right on the scale, putting it in the class Ï'e31'tl 101íew eater theme lousino. of nay-- "No. He was killed in an accident known as "tachometers." mannfeehm. ENGINEERS male shortly after he placed the bracelet on my $ Wee áo k`t.nttoSSOOFm . Writentoô ell arm. That is why I have never been able open tut you. See Ience tuttwn reduenon. Write wads th. offer I,.tG for full oarncuta,+. FREE AND l'ID;PÁLL! to remove it. No one but he knew how." AMERICAN SCHOOL OF AVIATION, Opt T443 (To be Concluded.) THE FIRST TROLLEY. eat So. Oeaebem Si,..,, Chicago, Illtaola. (Continued from rage 750) A SPEEDOMETER FOR SMALL controller handle while the brakes are re- TYPEWRITERS BATTERY MOTORS. 610 and up. All makes. Save $25 leased. the power will be automatically cut to 650 (Continued from page 770) off, the brakes will automatically apply in on rebuilt at the factor,. by the well. Iowan "young !'meet. ." Sold for emergency. sand will he applied to the rails, low rash-- Inttallllle,ll nr reined. out pull the cord. Thread the the front door opened. the steps lowered, R,etial applies nt, purchase price. when you Write Cr full details mud ,narur other end under the staple, F, and up thru and the rear door unlatched so that it may tee. Free trial. the small hole, g. in the arm, D. Connect be opened by hand if desired. Should oc- YOUNG TYPEWRITER CO.. the other arm up in the same manner. Tic casion arise for the operator to apply the Dept. 619 Chleags the end of each cord to its appropriate brakes in emergency, the door and step, arm, the length so that when the sand and brake operations are performed Auto Battery Charging Pays 81 Prpet. adjusting Oa re f 600 Watt HO Chargers clearing 120 arms are up flush against their respective by the nacre moving of the brake valve to $60 a month eatra profit. $15 pate this handle to emergency position. thereby mak- money -maker ln your gangs. Balance In eight stops, e, Fig. 3. and the cord is taut, the monthly p.3-manta at 1.0. amer -beef guar- slider will be about I /16" from the outer ing the operator's duties on such occasions antee. Mall thla ad wIth name for full Par- 3E.Troy.ObiO ends of the guides, H. as simple as possible. ticulars Hoban Bros Co.. Dos Pou benefit by mentioning the "Electrical Experimenter" when writing to oderr isrrs.

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This masterp'ece contains 160 pages. 400 illustrations. The most comprehensive Wireless Course ever printed. Size of book 5 "x9 ". Printed on extra thin paper, so book Contains 160 pages, 350 illustrations. Size of book can be slipped in pocket. Handsome stiff cloth cover. 61/4" x 9 ". Very fine flexible linen cover. FREE with a year's subscription. FREE with a year's subscription.

This is a very limited offer. It may be withdrawn at any time. due to the tremendous cost of paper, which IS JUST DOUBLE WHAT IT WAS ONE YEAR AGO. We only have about 2000 each of these fine books on hand; after they are gone we cannot reprint the books until conditions become normal again. THIS MAY BE TWO YEARS OR MORE. Now is your chance. The publishers of this journal have earned an enviable reputation of giving more than 100 cents' worth for each dollar spent with them. Profit 5e by this liberal opportunity NOW; it may never be made again. Electrical HERE'S THE OFFER Experimenter Subscribe to THE ELECTRICAL EXPERIMENTER for one year, at the regular subscription price of $1.50 per year (Canada. foreign and N. Y. C. $2.00) and we will send you FREE, POSTPAID, either one of the above books. If you sub- t:rnllemm: ` scribe for two years, BOTH BOOKS WILL BE GIVEN FREE, POSTPAID. l'leasc a t e r utncription ll., T ÌI E ELEC- If you are a subscriber at present,take advantage TRICAL ENI'Eltl UENTER to r t h e of this wonderful opportunity anyway. If you l.rni of eae do, we will extend your present subscrip- for thieb I enclose here- tion for one year. with Non ein also s.ud n'. at once This Offer Limited. Act Now. h'Ilfai irrlwul your.,. h000k.. EXPERIMENTER PUB. C0. tEt&12 TER'make" ó k`. -Pis end E4 tblalt 223 FULTON STREET This book will weigho7 lbs. It is the greatest Electrical and ü'ireless reference a tor. .. NEW YORK CITY work In the world. And all for $1.50

Pou benefit by mentioning the "Liectrical Experimenter" when uniting to advertisers.

www.americanradiohistory.com March, i 9 18 ELECTRICAL EXPERIMENTER 60

Opportunity Exchange I'OU will probably Mal more opportunities and real bargains in these columns than anywhere else in the count r.. Most -.,,,d thine. of life are hard to find and worth going after-these little ads illustrate that point; you alone will be the real lover if .,,u ,fum'I ink, the time to scan through these columns. - Advertisements in this section six cents a word for each insertion. ('punt 7 words per line. Name and address must be included at the above rate. Cash should accompany all classified advertisements unless plaited In .,n au r r Jr. td advertising agency. per cent. discount for o issues. 211 per crut. discount for 12 Ten issues from shove rate. Objreuon:d,le or misleading ads trimsenn.o. ma accepted. Advertisements for the April issue should reach us not later than February 23. OVER 100.000 PEOPLE READ THIS JOUiLNAL EXPERIMENTER PUBLISHING CO., INC., 233 Fulton Street, New York, N. V.

BIG PAY for and AERONAUTICS CHEMICALS men women. Tremendous demand for draftsmen. Pleasant work; salary $100 to 5200 a month. Study spare time at home; we AERIAL AGE, Americas leading illustrated 8u $4.00 will help you secure position when aero- PREPAID DIFFERENT CHEMICALS, qualified. weekly, presents the latest developments in -Mercury, Sodium. Iodine Magnesium, Aluminum, \ \'rite today for particulars. Special offer to men nautics throughout the world. Up to the minute Iranyl Chloride, Silver Nitrate, Mercuric- Oxide. subject to draft. COLUMBIA SCIIOOI. OF technical information concerning aeroengines. aero- Zinc Dust, lodoform, Manganese Dioxide, Calcium DRAFTING, 271 3LcLachlen Bldg.. Washington, planes. accessories and patents. Complete model Sulphide, Hydrochloric, Oxalic and Acetic Acids D. C. news and instruction. Trial subscription six together with 65 others. All are contained in glass WANTED-YOUNG MEN to introduce Liscien months. twenty.six issues, one dollar. Sample copy bottles. Generous quantities of each. We do this Chemicals, 10c. Aerial Age, 280 Madison Ave., New York Minerals, Apparatus. Special terms. to advertise the purest chemicals manufactured. Write- Liscien institute, 308 Mathews Ave.. Knox City, N. V. Full list sent free upon request. Sent prepaid to ville, Pittsburgh. l'a. any address in the world, $4 complete. C. O. D. AUCTIONS terms accepted. Thr Swimmer Chemical Co., 1004 Park Place, Brooklyn, N. Y. MISCELLANEOUS AUCTIONEERS make from $10 to $50 a day. EX P ER I NI ENTAL Free catalog. Missouri Auction School. Kansas CHEMISTS:! Perform STAMPS -61 all different. free. Postage 3c. City. chemical experiments with apparatus described in Mention paper. Quaker S:amp Co.. Toledo. Ohio. "Experimental Chemistry." I sell any piece of RUBBER STAMP with your name BOOKS apparatus you nerd. Each and every piece guarani and address teed. GLASS STOPPERED REAt,ENT BOT- and agent's wholesale t prices, 25c. Central Stamp TLES with name and symbol blown in. One Works, Newcastle, Tnd. TO CET BETTER PICTURES: Read the quarter pint. Special price $3.50 per dozen, 40c GENUINE DIAMOND CLASS , week. CUTTER Amateur Photographer's Weekly; illustrated; each. Send for list. John F. O'Brien, 149 Valley Drill, state which, prepaid. SI. l'nset small dia- I prize competitions; print criticisms; many unique Road, Montclair, N. J. ten dollars per carat. up. Special price. features; $1.50 per year; three months trial sub. EXPERIMENTERS! Are you interested in onmonds large stones. Leo Hirsh. Box 305, Elkhart, Ind. scription 25e.; Abel Publishing Company, 401 Caxton Bldg., Cleveland, Ohio. novel chemical experiments? Send 25e for large WE HAVE a limited number of beautiful art collection. 3lerel Sager. 44 Apple St., Tiffin, Ohio. pictures on hand of Nikola Tesla. and Dr. Lee 30 MAGAZINES -All different, late issues. De Forest. These make a handsome decoration Value $3. Yours, only 25c prepaid. Eastern for any laboratory or workshop and should he N. (Bureau, New Egypt, MINIImMIINIIIINIII11uIIIIIIINIIIIINIIIIIIIIIINIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIININnIMNNI@h prominently displayed. Price for both, prepaid. 10c. Experimenter Pub. Co., 233 Fulton St.. Nen MINDR EA DING course, complete, $1; trick York City. lists, dime. W. \\'ooley, Davenport, Iowa. 1520 St. Marks Are. BIG BARGAIN IN TENNIS RACKETS -We A BINDER for THE ELECTRICAL EXPERI- have a small supply of Tennis Rackets, made by MENTER will preserve your copies for all time. Brooklyn, X. 1. me of the largest firms in ihr country. on hand Price, 50e. Postage on 3 Ihs. is extra. Send for which we will close out at the following prices: one today. Experimenter Publishing Co., 233 Ful- The Experimenter Publishing Co.. No. 2375 -Extra best Tennis Racket, $5 grade. ton Si., New York City. air 233 Fulton st., dried ash, popular long oval form. concave walmit FIRE SALE OF SLIGHTLY DAMAGED wedge. superior quality of gut: each $2.75. BOOKS. Due to fire in our stock rooms, a great New York City. No. 2377 -First grade Tennis Racket, second growth many of our books were water stained, but not ash. walnut and maple throat, very good grate of otherwise damaged. Rather than dispose of them Gentlemen: gut; handle of cedar with leather cap; a $3.25 to dealers we prefer to give our readers the bene. grade; each $L85. fit. Look at this list: Our celebrated Wireless The advertising columns in the No. 2376 -\tedium grade Tennis Racket made of Course. 160 pages. 400 illustrations; Experimental "E. E." certainty briny excellent re- the same stock as No. 2377 except the gut. A perfect Electricity Course. 160 pages, 350 illustrations; How sults. I have sold 250 spark coils $2.25 grade. Ideal for beginners. Each $1.33. Ship- to Make \Tireless Sending Instruments. These ping weight of each size two pounds. Send for one three books for $1.00 prepaid. Regular selling and orders are conning in at the rate today. Our stock is limited and policy is! "First price of these three books is $2.50. We guarantee of 10 a day, all resulting front one Come, First Served." Don't forget to include money you will he satisfied. Experimenter Publishing Co., for postage. or we ship express collect. The Electro insertion in the classified columns of Importing Co.. Inc., 233 Fulton St., New York City. the E. E. 233 Fulton St., New York City. OLD E.E. BACK NU MBERS -\\'e have some 17.eould highly recommend titis valuable old E.E. back numbers on hand as per MOTORCYCLES paper as an advertising medium to list below: MOTORCYCLES $25 1015. ,those who to FROM UP -New and desire trade or sell. second -hand. Easy terms, large list to Jan. ..price each $.35 Sept. ...price each $.35 chnose from. March.. Oct. ... " " Respectfully yours, all makes. Send 4c stamps for Bulletin "A." April. " Nov...... Peerless Motorcycle Co., Vtatertown, Mass. .. " .," ,. .. .. J. EISGRAN. May Dec. PATENT ATTORNEYS Julie ... " " 1917.

I 1. Illlp July. ... " " " Jan. .. 5.20 m 11111111111 1111111 (III III illl'11I1010111 ill "PATENTS AND SUCCESSFUL PINOMO - August . ': " Feb. T10N" -This book free: Tells how to obtain a Sept. ... " " " March. . .. le April. .. 64 ELECTRICAL SUPPLIES AND APPLI ANCES valuable patent, and make your idea pay. Manu facturera T .. .. May ... .. constantly writing me for patents. can June help you sell yours. Lloyd W. Patch. Patent .. .. BUILD a Quadruple \\'inishurst Machine for :Attorney, 26 Le Droit Bldg., Washington, D. C. July. ... work. 1016. Aug. Xray Drawings with instruction 25c; also INVEN'T'IONS UAN1 ED! Manufacturers ,.. on anything electrical. free. P. C. Jan. .... " " $.35 Sept. ... Information constantly writing us for patent List of inven- o 44 Brunotte. General Delivery. New York City. Feb. " " o . .... tions actually requested and book "Dow to 011. March .. Nov. ... IA 46 FOR SALE -High Frequency Transformers tain a Patent" sent free. Send rough sketch for May ... " Dec. .15 "Oudin" style, $4.51. J. C. Swimmer, 10(14 Park free report regarding patentability. Special as tune 1918. Pl.. Brooklyn, NI. V. sistanee given our clients in selling patents. Write ,. .. . ¡an. " " $.15 for details of interest to every inventor. July ...... NIA' N ET( 1S, Motors, Magnet wire, Wireless (handle, $r Chandler. l'aient Attorneys. 21 years. 351 August . " " " Feb. .... " goods, Telephone Est Coils, and apparatus. 7th St., Washington, D. C. We can fill orders at once upon receipt of your etc. Prices far below cost. Willard St. John, remittance, and if you have not these numbers al Hawley. Minn. YOUR ILEA WANTED. PATENT YOUR ready now is your chance to get them, as they INVF :NTI/IN. I'll help you ,uarket it. Send for probably will be snapped up very quickly. Fx. FORMULAS 4 free books, list of patent buyers. hundreds of rruncnter Publishing Co., 233 Fulton St., New ideas scanted. etc. -Advice free. Patents adver Fork City. "FOOD l'ONSERVATION" -Your Patriotic used free. Richard B. t omen. Patent Lawyer. 13o Duty. Delicious butter made at 7c per pound by Owen Bldg.. Washington. D ('.. or 227'-T \\'nol BUSINESS OPPORTUNITIES simple merging process. Guaranteed instructions worth Bble.. New York 25e. Norman Ilvri, Dept. F., Hemet, California. PATENTS ON EASY P.AVMIENTS. Send SPECIAL OFFER -Luminous Paint, 15e; Sit. model nr sketch for Free Search and I t- rtitied ver-plating Powder, 15e; Liquid Courtplaster, 15c; HELP WANTED Registrati of Your Invent' for Your Protec- Soap Bubble Liquid, 15e; Straw Hat Bleach. 15e; tion. Free Book Tells Wham to /neon and Ilnt. to Obtain a CollIapsible Tube Tooth Paste, 15e: Resilvering Mir- $100 MONTII paid menwomen, 18 or over. Patent on Lass Payments. C. C ror-Liquid. 15e; l'olish for Tan Shoes. 15e; Dress- Thousands government clerical positions open. (hugs $r Co., 503 Loan S Trust Bldg.. Washington. ing for Tan Shoes, 15e; Paint to Make Oil ('10:11, Pleasant work. Vacations with par. 7 (tour day 13e. Full Directions how to make and use. Full Pull unnecessary. Cotmnon education sufficient. PATENTS - AVabout advance attorney's fees. set of 10 only 50c. Remarkable bargain. Stamps Examinations eieryywhere soon. Write immc,li Not due until patent allowed. Send sketch for free accepted. Sidney Specialty Co.. 233 S. Fulton St , may for list positions open. Franklin Institute, report. Books free. Frank Fuller. \\ ashmgion, New York City. Dept. \l. 27. Rochester. N. Y. I). C.

1' nu ben frit by menlinniuu the "Elect t trot E.rrerunen ter" tchen ti riling to ad: cytise ,s

www.americanradiohistory.com 808 ELECTRICAL EXPERIMENTER March, 1918

\\ l'HUNOGRAPHS TELEGRAPHY IRELE» TELEGRAPHY -both MORSE AND WIRE- WIRELESS- \'e prepare you for Signal Corps BUILD YOUR OWN PHONOGRAPHS and LESS. also STATION AGENCY, taught quickly. work, radio service. Our instruction includes manufacture them for profit. Drawing. Instruc- TREMENDOUS DEMAND -much greater than radio. buzzer, wigwag, semaphore, and military tions. Parts, Price List. Blue Print, etc., complete, supply-PERMANENT POSITIONS SECURED. drill. Prepares you for rapid promotion in service. sent free upon request. \ \'rite today. Associated BIG SALARIES recently raised. IDEAL BIG OPPORTUNITY FOR DRAP[AGE MEN. Phonograph Co., Dept. E -1. Cincinnati. WORKING CONDITIONS- -short hours, vaca- Write today for illustrated booklet and full in- tions with pay, sick and death benefits, etc.-pre. formation. WIRELESS TELEGRAPH DEPART- vailing. GREAT OPPORTUNITIES FOR AD- MENT. GRACELAND COLLEGE. Lamoni, Iowa. PRINTING VANCE3IENT. WOMEN OPERATORS also greatly desired by Railways and Western Union. COILS -t4" guaranteed, send $1 with postage. expenses Dubs, 1534 Pitkin Ave., Brooklyn. N. Y. YOUR name on fifty "Styloprint cards," 35c. Tuition reasonable. Cheap living -can Alfred Waltham, be earned. Oldest and largest school -established Card case FREE. Imprimatur Press, Union SALE account of financial rea- Mass. 43 years. Endorsed by railway, Western SPECIAL -On and Marconi Telegraph Officials. Large illustrated sons we are forced to sell a large number of the at the SPECIAL INTRODUCTORY OFFER -100 catalogues free. Correspondence courses also. latest type of WIRELESS code -learners Name cards, Claude Write today. ENROLL IMMEDIATELY. Dodge's reduced price of $1. D & W Mfg. Co., Box 725, Envelopes, Noteheads. $1. Madison, South Dakota. \\'ehinger, 105 Ludlam, Lowell, Mass. Institute. Lone St.. Valparaiso, Indiana.

Scientific Exchange Columns you have at the persent time some things for which you have no further use. Do you wish to exchange them for something UADOUBTEDLYfor which you have immediate use? There is no surer and quicker way to do this than by advertising your articles in these columns. The ['cry people, the Only people, who could possibly have a.use for your things read this journal. More than 75.000 interested people will see your ad. It is furthermore the cheapest advertising medium for you in the country. Dealers advertising accepted in Opportunity Exchange columns y The rates are: Fire cents per word (name and address to be counted), minimum space 3 lines. Count about 7 words to the line. Remittance must accompany all orders. No advertisement for less than 50e. accepted. We reserve to ourselves the right to refuse any advertisement which we consider misleading or objectionable. Advertisements for the April issue should reach us not later than February 23. The Classified Columns of the "Electrical Experimenter" Bring Positive Results. Subscribers experiencing trouble in dealing with ally advertiser should notify the publisher very promptly. OVER 100,000 PEOPI.E READ THIS JOURNAL o

FOR SALE -New $17 Spencer Dissecting Micro- 6 VOLT generator and starting set. good condi- WANTED -Ives Electric Trains for "0-Gauge" scope. with mahogany case, $12. $8 large metric tion, will sell or trade for wireless instruments. Track. Also cars, track, switches, crossovers, etc. scales, $5, and $3 scales with weights. $2. Send \W m. Frey, Bedford, Michigan. State what you have. condition and lowest price stamp for description. Reginald Pitts, Hanover, in your first letter. C. E. Robinson, Portland. Pa. P91111EMCIIIIOESPJl1"17n'TI0.I!II11"m'1lil@IPYIIIJf'?II III 7B! R% Conn. FOR SALE- Adjustable Barbell, Dumbell, Ket- TO SWAP" ? é tlehells and Course. All plates 165 lbs. 525. Paid \\'ANTED- Motorcvle engine, with or without "WANT $37. T. Voegeli, 2351 Park Ave., St. Lows, Mo. carburetor and magneto or coil. Write. Harold FOR SALE Johnson motorcycle first New York. Du you realize that these "Scientific Ex- -Iver -class Lambert. Haverstraw, change Columns" are the World's most re- condition, 1913 twin cylinder; good running order. nuwned "Swap'' market? "THE ELEC- price $75.00. Howard B. Stossel, Front Royal, \'a. TRICAL ENPERIMENTER" prints 90,000 FOR SALE-t,:¡ H.P. Emerson A. C. Motor. TRADE OR SELL -Motorcycle engine, If. F. G that at least engine. copies of this issue; that means Will trade for good rectifier or water motor. All condensers and outfit for !s Horse gasoline 180,000 readers see this page and probably E answered. A. Hampton. Box 263, \Whitewright, 413 Boston St., Galion, Ohio. Reuben Shumaker. 5 a great many more. Our readers whu adver- Texas. tise here seldom advertise the same thing FOR SALE -15 dial Omnigraph (Morse code), 5 twice -usually within five days after the 110 volt E key and sounder. Harry Baker, Box 48, Green- \\-ANTED -2 K.W. 60 Amp. dynamo issue is out the advertised article has been ville, Ohio. or less. Harry D. Morris, Quitman, Mo. sold, or swapped. The many testimonials which we print here from time to time are COMPLETE CHEMICAL OUTFIT. Cash or ample proof of the almost miraculous pull - exchange for wireless goods. Toth. 1628 First 5 Ave., New York City. for list of small stuff for sale cheap. ing power of these columns. WRITE Mass. R. W. Chaffee, 67 Thurston St., Somerville, FOR SALE -$11 Omnigraph; Marko,storage bat- Look around in your attic or workshop E tery; Crystoloi detector. \\-rite offer. George and you will tind dozens of long forgotten Dimon, 367 Genesee St., Utica, N. Y. E very use- volt direct current motors. 1/5 H.P. articles, useless to you now, but \\-ANTED -Twin cylinder motorcycle engine, SELL-110 ful to someone else. At a ridiculously low I/8 H.P. $6; 130 ohm relay, . exhausted complete. (lave various articles to trade. What $15; cost you can either sell or swap such articles. ij coherer, 5150; leather tool bag, $2. C. S. Haines, ffi bave you ? Benj. McCau1, Ayr, N. Dak. Johnson City, Tenn. And remember this fact: The U. S. Postal E BICYCLE MOTOR outfit, $15. Brand new auto Laws protect you. No one can "do" or cheat i= carburetor, $4. Motorcycle Presto tank. $6.50. you. Of 3,495 "ads" published in these col- Joseph Tucci, 122 East 32nd St., New York City. out- MINUTE PHOTO CAMERA with complete umns during the past five years, only twelve WILL PAY SS for a No. 2 Ommgraph (holds motorcycle engine, or what fit will exchange for complaints were reported to us, and each tË fifteen dials). Must be in good running order. have you.' \\'m. Smith, 337 Hippie Court, Canton, and every one was adjusted to the full sat- Sell a vest- pocket Kodak and daylight des-eloping Ill. isfaction of the complainant. a tank to fit vest- pocket for $5. Radio, Gwynedd Valley, Pa. It matters not if you have old books or ENCHANGE -$100 Generating Plant. Engine, FOR SALE -Savage automatic 22 calibre rifle. magazines, a kodak, electrical or chemical George Sump M M Generator, batteries, for 54 to 1 L.W. Transmitter. price $8: ;5" spark coil, price $1. apparatus. scientific instruments. bicycles. 3000 (Ihm phones, 8 fuse machines, 2 $26 Violin, $12; $3' turn, Box 23. Anacortes Wash. typewriters. moving picture air blocks, each 15e; 2 blocks fuses, 90 Amp., etc. s with rifles. watches, structural toys, etc., All 2 each 73e; $30 piano music, $20. Other barga,ns. cash n these and countless others can be speedily Reuben Scholz, Sheboygan, Wis. WANTED-Complete Wireless Outfits; pay disposed of here. Try it and he convinced. or exchange photographic goods. O. Ingmar Ole - e BARGAINS FOR SALE- Erector, cost $13: No. Gas son, Ambrose, No. Oak. gl.l ®WUm115wml 121s 11111111 2A "Brownie" Camera; Bicycle "Search- light": Hunting Lamp Electric Lantern; Camp Ax: Bicycle Horn; "Boys' Book of Electricity' ; FOR SALE -One Kilowatt transformer; $12 my wireless and experimenter's appa- machine; takes Knapp Leader Motor; Striking Bag; Spring Exer- Brandes superior phones; E. I. Co., Static ratus. \trite C. Pfeiffer. 41 Rohn's Ave., Detroit. ciser. All practically new. \ cry cheap. Gordon and other wireless and experimental apparatus. Mich. Bennett, Darlington, Md. Also H.P. Gas engine. Particulars for stamp. tt Texas. Harold Rice, 1409 Harrison St., Amarillo, BARGAINS -First $25 takes $62 worth of wireless and electrical apparatus, including audios. novel inventions. Useful, and phones. coupler, motor, variable. etc. All perfect FOR SALE -3 The ail I had in your magazine some time {roduceable at low cost. W. M. Seyferlich, 430 condition. Act quick. Vi rite for list. Aubrey Wrightwood Ave., Chicago, Ill. ago brought me 122 different answers; they Tholin, 1339 Fifth Ave., Rockford, III. from all over the United States and came FOR SALE -Remington ('. M. C. 22 Caliber FOR SALE -Single cylinder Indian motorcycle. even from Canada. The advertising columns Repeating Rifle. Cost $14. Will sell for $9. Rifle Ready to run with exception of few repairs. Price in your magazine are the BEST I ever used. in first -class condition. Never used. Write for Mooresville, Ind. information. A. Stropko, 9323 $25. W. R. Milner, I obtained splendid results for such a small further Joseph Buckeye Road, Cleveland, t Ihio. ad. FOR SALE- Sending and receiving set. Price on request. Instruments sold separately. \\'ANTED -Copy of book "Michael Faraday, Ills list sent Yours very truly. Also. an Jack Cox, Thomasville. Ga. Life and Work" -by Svlvanus Thompson. LOUIS E. KRIEG, ohmeter of the Roller -Smith type or a Wheatstone include 110 volt 134 North School Street, Gloversville, N. V. bridge; must he in first -class condition, and WANTED-5 or 6 K.W. Transformer ELECTRICAL Ex Secondary. Ed. Dick- galvanometer. H. W. Seeor, e'o Primary to 10,000 to 20,000 PERIMExTER. 233 Fulton St., New York City. son, 2.014 E. Denny Way. Seattle. \Wash. 1-on bole/it by mentioning the "Electrical Experimenter' when writing to advertisers.

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No. 3 ',kit- HAWKINS AI II I rIL11i

ELECTRICAL GUIDES No. 4 ' These hunks plan. elrrinrily at your Nut:rr end, They rover user) Imaginable subject. principle. lhear.s. pruLlrm. trurthle. and wa, of doing things :all elerlri: ., Every subject Is indexed so that you can tiers right to it. Thev are a stud) No and a reference Wilde In one. tvritlen Ill plain .very day l:unguage -nu wasted r. only that you need to know rhurk full of nut tn- the- minlrle electrical kittowlr ;. The guides :err a roundel,- nurse ill eleetriral ettglnelring. They will help yon ill No. 6 evert detail of the day1: r I...Aril-al work. Yon can't ask an .lest rival rots tiou that . r,lat- ll:rw kin: Enid., can't all s r r. Pocket -Size Flexible Covers No. 7

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11 ., 1 ...nutlet.. i:tit lea mauls In the Naval Electrical Dept. Il , .1 .Ibl.' \t # New Ynrk, N. Y. r, f el r ore indes . : f Ihr u- reopen 11 III you n:olnrr s-i r Inll,:,lnanr."nurrh f ItEf. "l'Ire Ilnwklns 1: ha4.s are groat holy . I Thi.a index lids Iles-II 1l:,.e o Tin. :I : I:ulldr.:r1. n Ill. g nd1o l'un, Ilhray for pre Ti t me the S.,al I:hctrle loon.rl 11I ai h I gold 1 lad IIn16Ing le.nall 1I9 . I.. r planuni to .ruinr e ail. rent n:l.,.'n lutin w111r11 ll.y rover von. Ihoruheh I J rrdo 1 e, r I e ; 'f n d, dud i h. ,I. Vortioll. -sslldr all the tent Infer l' 1 -s I tÍtllmt II I return llan I1 ue .. q o r 1 negieren enntainrd ill , M. ihr Iterri,ing Ship. Itronitbil N \ nothing. I ,r ICI I,. t1'I rlrelrleal guides. pea !I çI Superintendent There ore fit er Et.- w nl a a a , ,rne.

, 1 h r: I. il 'i one now auprriotrudent of the lop rr°a3 refer- Dive 'l' I 1 l aunn9 tir Ilydrn kll,tnr Ovate n+. :sires Ton find ., and Hawkins anidns a twit. storin groan whin you want Sian at ur le Ian In tinkling tints° a rslIlhl polllo-. klknow In , \\' lie Swartz. Uwuwllle. untarlo. THEO. AUDEL & CO. ,fan11Y, tlrruoailnn Wireless Operators st

"1 I ate orked wind.... for ben 72 Fifth Ave. New York, N. Y. Ruda.., Ad dyers sear, but I w I had the,. Ixmkn as they have n -:rl toe a kreol dell of Irauhle' I1. tI.,rshall sHrrldrnr' .. Strainer SI At It No 2 SEND NO MONEY- USE THE COUPON walkervllu., truss Heferente I I Ma, c1,

www.americanradiohistory.com "Think Beyond Your Job!" "There is not a man in power at the Bethlehem Steel Works today," says Charles M. Schwab, in the American Magazine. "who did not begin at the bottom and work his way up. These leaders rose from the ranks. They won out by using their normal brains to think beyond their manifest daily duty. "Eight years ago Eugene Grace was switching engines. His ability to out -think his job, coupled with his sterling integrity, lifted him to the presidency of our corporation. Last year he earned more than a million dollars. "Jimmie Ward, one of our vice -presidents, used to be a stenographer. But he kept doing things out of his regular line of duty. He was thinking beyond his job, so I gave him a better one. And he has gone up and up. The fifteen men in charge of the plants were selected, not because of some startling stroke of genius, but because day in and day out, they were thinking beyond their jobs."

'.TEAR OUT HERE \\'hat about you? Are you satisfied just to hang INTERNATIONAL CORRESPONDENCE SCHOOLS on where you are? If so, rest assured that's as far as Box 5315, SCRANTON, PA. you'll ever get. But if you scant to be somebody, to Explain. mthout obligating me. bow I can qualify for the poçftion. or in the climb to a position of responsibility, get ready for it. subject, before Irhi.b I mark X. Do what you are doing now better than the men DELFT/RI( AL E\GI SEER Bridge Engineer [,TRAFFIr MANAGEMENT beside you and train for the job ahead. You can do Fleclrid.n C Structural Draftsman C Cartoonist Electric Structural E ILLUSTRATOR it -in spare time -through the International Corre- O Electric gbR Ój í o,cipa Engineer Perspective Drawing spondence Schools. Electric C ar Running C A Tc tT Carpet Designer aDcaftl Tnction l Wallpaper Designer evy ris [ Architectural For 25 men h D an C red er D Bookcover Designer years of ambition with I.C.S. =!p Electric Designer Building MOoumeot Designer have been making spare hours the stepping -stones to Teleg raph Engineer Lumberman OCommon School Subjects MEI II ANICAL ENGINE/ [Concrete Builder High School Subjects successful careers. Last year more than 5,000 Methenical Draftsmanan [ PLUMBER S STEAMS F ITTER rtio reported that their studies had won for them advance- E Machine Shop Pr D Heating and Ventilation [ Teacher E eroa Practice nR Inspector TESTI LE OVERSEER OR SFPT. ment and increased salaries. In the Bethlehem Steel a or Designer [ Foreman Plumber C Cotton Sienut:cturing t \'orks alone over 100 men right now are putting Toolmaker O BUSINESS u'emp4lr! wooleo Manufacturing C Bookkeeper G (lIEY If.AL ENGINE lit their spare time on I.C.S. courses and thinking, 10 Work h Typist ioI Chemist C Blacksmith grapher E ahead, getting ready for the better positions that El Accounting C MISE FOREMAN Ill, ENGINEER sneel.Ma.1 Worker Higher Accountantoununt Meta Mining surely await them. And over 130,000 others in D Al'T11MI)RILES Railway Accoonlan, C Metal Mining offices, on Automobile Repairing CCom Law CMeullurgist or Prospector shops, stores, mines. and mills, and rail- E TEAM ESGISI LII Good English ,asssyer roads all over America are preparing in the I.C.S. way C Steam- Electric Ingineer G SALLCM li4St .P [S.t)1GATlOS .PlSI,u to take the next step upward. C Stationary Firemen C o l M AS C lour Rost Maori* CFrench C Marine Engineer C Windoww TrimmerTriri C A1,1t11 FLTUID: LJCerman Refrigeration Eogine,, C Writer C Fruit Crowing lulian Join them! All you need is just ordinary brains, jCas Engineer COutdoor gn Painter C Vegetable Crowing the will to do, and the firm resolve to think ahead of EMIMIL ENGINEER 1 l Ill. Olive and Dairy tog C Surveying and Meppiog Railway Mail Clerk Poultrylt Raiser the job you now hold. The LC,S. are ready to make. C R. R. Coostructing C Mau Carrieraier G Poultry Breeder the rest easy.

Name _ Make your mart NOW. Mark and mall this coupon. Occupation ^loyer INTERNATIONAL. CORRESPONDENCE SCHO9LS Boa 5375. SCRANTON. PA. Street ani.`.- Coy_