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eCieliìtY LEARN AT Here's the chance. you've been waiting for ! Here's your opporttinity to get out of the small HOME pay class. Here's your opportunity to earn the money and do the kind of work your ambi- send tion calls for! ' Write me at once -TODAY! Just the coupon or a postal. I will give you 20 complete les- sons in practical electricity FREE! Think of it! My per- sonal and individual instruction for 20 lessons without a cent of cost to you if you act quick. No charge to you for these 20 lessons, more now or later. I make this sensational offer to secure a tew you a live students-to show, too, how quickly I can make Master Electrician, no matter where you live, or what you do. only. But you must act at once! This offer is for a limited time Remember, these free lessons are not merely sample lessons, but are a regular part of my full and complete course in electricity. Send the coupon without eI, 1.ty -- TODAY! EARN $2,500 TO $4,000 A YEAR the doing it. Don't let false fear or doubt say you can't! Give Others are You can now butter man within you a chance on this great opportunity. your spare time, and without giving up your pres- qualify at home during the or occupation. for the most wonderful of all fields open to ent position Yes, no matter man -the great Jod growing field of Electricity! ambitious a of electrical ex- know a thing about electricity or never had bit if you don't so that take you in hand and make you an Expert Electrician, perience, I will do it so easily earn $2,500 to $4.000 a year and more. And I'll A. W. WICKS, E. E. you should wonder how it was quickly and with so little effort on your part, that you'll Formerly with the possible. No books or tools to buy. General Electric Co.; lorotrr General Man- ager of company ola- I TRAIN YOU BY MAIL afaeNtriop Jenney the whole matter so simple for you that you I will instruct you personally -make Expert Electric Motors; also When you have finished my instructions you are an can't help but Rum. I show formerly with Fair- take a big paying job or start in for yourself. Electrician -ready to on jobs banks, Morse & Co.; only how to do practical electrical work, but how to estimate Engi- you not means to be trained noce C'aasallin,g you can take contracts at big profits. That's what it of so that you can't neer and Director of my practical experience. Don't let anyone tell that.you by a man can, NOW, since I have the lI'irks Electrical clectrie ity through home study. You positively institute. learn Remember, too, that my perfected my v.,m,!urful metI od of instruction. instruction is practical, as I am a practical Elect rici tn. Sec what my st udents have to say!

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_...... NEW - B'I G 300 PAC E ELECTRICx A .:,.. X ÖUCK' 5llO. ' and WIRELESS CATALOG ' d MORE THAN EVER JUSTIFIES YOUR VERr)ICT ~ J IT IS THE ONE CATALOG WORTH WHILE ra,N.o...rc, l50 p yTi a ess ÁTinstruments 150 pp. electrical ,t.,-,ft!cs fp. The WIIäm !. Duell ANNOUNCEMENT WIRELESS AMATEURS

We announce effective at once these exceedingly attractive reductions on the following wireless ins, i amen t ; Price Price Prie f re Type T-0 Thordarson Flexible. Step -Up No. 1915 Detector Stand 1 $2. rp St.' e Transformer $15.00 512.25 Model SAA Navy Type Receiving Trans- Type T -1 Thordarson Flexible Step -Up former. 19, .0 3 7.: , Transformer 20.00 16.25 No. 1091 Arlington Receiving Transformer 9.l I. ,e Only 8c in stamps Type T -2 Thordarson Flexible Step -Up No. 1092 Arlington Type R Receiving will bring this Transformer 25.00 19.75 Transformer 7. h,.; unrivalled cata- Note. -A Thordarson Special No. A7721 Receiving Transformer 6. .5 :'S log to your home. Protective Device included No. 44X6 1 inch Spark Coil 4. 3.5.5 free with each transformer. No. 39X0 inch Spark Coil 2. ...h The great cost of Catalog No. 11 these trans- 3 In No. 40X0 3á inch Spark Coil 3. t '5 catalog and the formers are listed at a alight No. A6012 Detector Stand low advance over above prices. if. exceptionally No. A395 Commercial Type Oscillation No. 61X10 Standard Tuning Coil 3, ., s. prices (often- Transformer 15.00 13.50 No. A560 Pancake Helix I. I. u . times fully 25e', . No. A7628 Oscillation Transformer 6.75 5.75 No. 71X0 Electrose Insulator...... el below usual re- No. R41 Receiving Set with Condensers 32.00 29.50 No. 73X0 Electrose Insulator . tí 24.00 22.00 r tail price) pro- No. R41 Receiving Set less Condensers.. No. 17X0 Electrose Insulator . tt hibits its distri- bution otherwise. WHAT OUR BIG CATALOG CONTAINS You may deduct 150 pages wireless instruments, 10 pages raw material; storage batteries: electrolytic rectifiers: high frequency soils el grt l,h mtruments; commercial and battery motors and dynamos; rotary converters: alternators: sewing machine 'mot ..; wet, the 8c on first motors: medical batteries; auto accessories; flashlights: electric lighting plants; Victrolas; books and general electric $1.00 purchase. s, Send Sc for this Catalog today. You need it 230-232 Si The William B. Duck Co, TOLEDUO, OHIIC

3...w.t'4!`t'.tä.. WAAITE FOR OUR FRET ON ELECTIUCITY BOOK- sg) -a profet^+n that is constantly calling for - tdble rw. ;. The rew-e care big for those with t 1 knot rot,Ivtt 4 of practise. .e Yee Y ork book inowledge, or a smattering 11 EV,.tncal School has started over 4,000 men t. -. .ces,f. r ch. : I .ncal careers. "LEARN B' DOING" a principle. 57 L.FL t u I- 6 trial' apparatus.ppa. where youwearn, oit In actual prace t t lectricali t This free book will show you how thoroughly we . mn tSls c'- Write for a copy. Address The New York Electrical School, 29 West 17th 1. et. Kan :o,i ,

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THAUGriranñ LENZITE CRYSTAL DETECCOR Patented May 2nd, 1916 A first class Wireless Detector is half the battle in tit,: %Wireless game. Have you tried the best and most effective, The "Lenzite" Crystal Detector ? REGISTERED Why Is Our Detector Near Perfection? If you want to have a per- fect receiving detector, try Being a user of an Audion Bulb and having firmly, after due test and consideration of "mfnera' them as unstable and unreliable very inconvenient, 1., ours. not satisfactory, detectors," discarded and being hard to .et. If in adjustment, I was very skeptical as to Lenzite, but glad to make the test and molt than ph a ed return same within thirty that I did so. days and we shall be pleased I found that the reception of signals with Lenzite as a detector quite beyond : +r y hope r}.at to refund you the price. I may have had. .1 Inasmuch as the mineral in question (Lenzite) seems to be "sensitive" nearly re r its sur- face on all sides, which is a very great advantage as it makes it ,st as easy to keep in adjustment as an audion, and brings in the signa , «Icr. yrcper attunement is accomplished, in a very loud and positive mann , and I m ,sr add I was greatly surprised as it, without any question, has viN -u me far greater results than any other sort of mineral detector I have trim, :,nl I hale tried to get all that I have been able to hear of.

Its clear, loud, readable demonstrations should make it v i , ' dce.i, able to operators whether or not they use audions, which consume powel hich I cnattc does not, and it is quite as good for long distance work as well. p 'h. l '.e glad to tell others of it. Very truly, HERBERT W. i21S: llì (6 IH U. S. L 'nse.) Send money order, express order or check for $5.00 and we will send you, postage LENZITE CRYSTAL CORPORATION prepaid, one of our Lenzire wireless detectors. 537 Chamber of Commerce Building Pasadena California

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www.americanradiohistory.com Ellectrica Experllmenter 233 Fulton S reet, New York Publisht by Experimenter Publishing Company, Inc. (II. Gernsback, Presiden ; S. Gernsback, Treasurer; M. IIyrncs, Secretary), 233 1.ulton Street, New York Vol. IV Whole No. 47 CONTENTS FOR MARCH, 1917 No. 11

FRONT COVER- "ELECTRIC FLYER MAKES 500 MILES AN OXYBENZYLMETIIYLENGLYCOLANFYDRIDE 801 HOUR" From a painting by George Wall EXPLOSIONS AND EXPLOSIVES- SECOND IAPER OF A VOLCANO- ELECTRIC PLANT THAT DEVELOPS 15,000 HORSE- NEW SERIES- "EX PERI \I ENTAL PHYSICS" POWER 789 By John Furia, A.B., M.A., F.K.S. 804 20,000 LEAGUES UNDER TIIE SEA 791 TILE WASHINGTON'S BIRTHDAY RADIO- RELAY SIIO(TTING BIG GAME ON THE ELECTRIC "MOVIE" TARGET 792 By W. H. Kirwan (9xE) 805 TRAVELING AT 500 MILES PER HOUR IN THE FUTURE RADIO DEPARTMENT-RADIO CONTROL SCHEME 806 ELECTRIC RAILWAY 794 IIE FOREST VS. TIIE ELECTRICAL EXPERIMENTER 808 AN ELECTRIC "MOVIE" MACHINE FOR TIIE HOME 795 THE CALCULATION AND MEASUREMENT OF INDUCTANCE HOW ELECTRO-I'NEUMATIC TUBES SHOOT MAIL UNDER- -PART I by II. Winfield Secor and Samuel Cohen 812 GROUND 797 STAGING A SCIENTIFIC ENTERTAINMENT ELECTRICITY ANI) LIFE By Dr. Frederick Finch Strong 798 By Raymond Francis Yates 819

0.JL41J1,141.J L10.111.1-10. IIJL!IJ! 0L!1JL!11 Tapping the Earth's Heat S the world progresses, it becomes more tamed from Niagara Falls, 150 miles distant. And of and more apparent to students of econom- late the great Chicago, Milwaukee and St. Paul Rail- ics, as well as to the layman, how utterly road runs all its electric trains over a distance of 440 inefficient and archaic our present coal - miles -not by coal, but by waterpower translated into burning practise is. There is certainly no electricity and led over thin wires along the tracks of greater anomaly than our present coal age, the railroad. and we may be quite sure that our great- grandchil- But waterpower plants are comparatively scarce. dren will read with amazement how supposedly in- Soon there will not be an untapt waterfall which is not telligent people the world over were using such an working to full capacity. What then? Our answer expensive make -shift as coal. comes from Italy. And this time the answer is not L!) There is an excuse for the steel manufacturer using visionary, or an editorial pipe dream either. For coal when he can mine it at his door. But there is no Prince Ginori -Conti now has a huge power plant located excuse for a manufacturer or a householder using coal in a volcanic region, which gives him 15,000 horse power a thousand miles or more distant from the mines. It is every second of the day as well as during the night. simply our present lack of knowledge as well as our He simply taps the heat of our earth by sinking pipes gross inefficiency that makes such things possible. First, five hundred feet underground and by this natural we mine the coal, compelling men, who could be em- heat costing nothing, he obtains heat for his boilers ployed to vastly better purposes, to be imprisoned for which in turn drive the electric turbo -generators. life within the bowels of the earth. Then we re- handle What he can do anyone can do at any point of the the coal a dozen times before we load it on trains. globe. True his conditions are favorable, for he did not Then we haul it over unbelieveable distances, burning need to sink his pipes very deep. But great depths are more coal in locomotives as we go along. Then, if no obstacles to a good engineer to -day. there is no rail blockade, just at the time when coal Speaking generally if we drill a hole straight down is needed most, we dump it into someone's yard a thou- into the earth the heat increases 1° Fahrenheit for ev- sand miles away from the mine. Next, we load it once ery 40 -50 feet. This means that under adverse condi- more and then sell it to a jobber and he in turn dumps tions we must sink our pipes from 8,000 to 9,000 feet it into another yard. He too sells it again to a dealer before we will reach a level where we strike 212° who dumps it into his own yard. The dealer, after he Fahrenheit, at which temperature water changes into kept it long enough, loads it once more and he also steam. Huge as such a depth is, as well as huge the dumps it again, this time into the bins of the ultimate cost to reach it, it is not unpractical. Remember it victim. In the meanwhile the coal has been rolling needs to be done only once; after that we will enjoy free up an avalanche of profits and interest as well as ex- power for centuries to come. Moreover, in many lo- traordinary expenses in foolish transportation and re- calities 212° will be reached at a depth of less than transportation. So at the end of the tortuous road, 2,000 feet. In exceptional localities such as Yellow- coal worth $3.00 a ton at the mine, now sells for $7.00 stone Park, boiling water comes to the surface while in and even $12.00 a ton ! It speaks well for us. volcanic regions a few hundred feet is sufficient to But this does not finish the story by any means. Af- sink our pipes. ter re- handling it a few more times, we now burn the Would it not pay municipalities to tap the earth's heat coal and while we do get a little expensive heat, we viti- under foot and supply the city with heat, light and ate the air, poison our lungs, make no end of dust and power at a good profit? Steam heat could be supplied finally' we must dump the burned coal-ashes -once to factories and householders for heating purposes more. And removing ashes costs additional money. at a low cost by running steam pipes underground. L!J Whence we remove ourselves to our library and read This, by the way, is quite practical altho not widely the latest magazine which tells us what a wonderfully known. In New York, for instance, one large corpora- 111.J enlightened race we are. This snakes us feel real tion supplies steam heat to consumers over an area of proud of ourselves. approximately 11/4 miles square (2% square miles) thru Of course, happy to relate, the whole world is not fifteen miles of steam mains, but of course the heat is peopled by fools. We are slowly beginning to realize now obtained by burning coal first. that there are other things to give us heat, light and Our big states lacking coal and waterpower should power besides coal. First and foremost we have "white certainly waste no time in trying Prince Ginori -Conti's coal" -our waterpower. It costs less to transport plan. Such terrestrial heat plants will pay for them- horse power by wire than by rail. Thus enlightened selves in two years or less. Syracuse runs its electric street cars by the power ob- H. GERNSBACh.

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THE ELECTRICAL EXPERIMENTER is publisht on the 15th of each York Unaccepted contributions cannot be returned unless full return postage month at 233 Fulton Street, New York. There are 12 numbers per year. Sub- has been included. ALL accepted contributions are paid for on puihcatioa. A scription price is 51.50 a year in U. S. and possessions. Canada and foreign countries, epeciail rate is paid for novel experiments; good photographs accomfanying them 82.00 a year. U. S. coin as well as U. S. stamps accepted (no foreign coins or stamps). are,,highly desirable. Single copies, 15 cents each. A sample copy will be sent gratis on request. Cheeks as second - 'ad money orders should be drawn to order of THE EXPERIMENTER PUB- THE ELECTRICAL EXPERIMENTER. Monthly. Enterai LISHING CO., class matter at the New York Post Office, under Act of Congress of ,larch 3, 1879. INC. If you change your address notify us promptly, in order Co., Inc., New that conies are not, miscarried or lost. A green wrapper indicates expiration. Title registered i'. S. Patent Office. Cdpyright, 1917, by E. P No copies sent after expiration. York. The contents of this magazine are copyrighted and must not be reproduced without giving full credit to the publication. All communications and contributions to this journal should be addressed THE ELECTRICAL EXPERIMENTER is for sale at all netesstands in the to: Editor, THE ELECTRICAL EXPERIMENTER, 233 Fulton Street, New United States and Canada; also at Brentano's, 37 Avenue de l'Opeß, Paris. 787

www.americanradiohistory.com 788 THE ELECTRICAL EXPERIMENTER March, 1917

CHARGE STORAGE BAT- TERIES from alternating current with the BLITZEN RECTIFIER. Safe, clean, economical.

HIGH FREQUENCY, HIGH QUALITY TEST GRAPHITE POTENTIOMETER BUZZER 5000 ohms resistance insures long The smallest, neatest and highest pitched life to batteries. Carbon contact buzzer on the market. insures long life to instrument. Don't ruin batteries and instru- ments with inferior imitations.

ONLY A FEW instruments selected from our new Catalogs can be shown here. Complete catalogs of Wirelessand Elec- trical Apparatus, Storage Battery Chargers. Parts and Supplies sent for 6c stamps to defray postage.

CLAPP-EASTHAM CO BLITZEN WAVE METER ROTARY VARIABLE CONDENSER 141 MAIN STREET CAMBRIDGE, MASS. THE Our small condensers, either 17 or Western Representatives A very attractive meter in portable 43 plates, are a little better value Southern California Electric Co. Berk Electric Co. form furnished in several types at because a little better quality. Our 625 S. Main St., Los Angeles, Calif. Portland, Oregon a very moderate price. Mahogany catalog tells why. case with hinged cover. 64 (0M+4 DE FOREST RADIO TELEGRAPH AND TELEPHONE APPARATUS THE value of radio equipment for motor cruisers and yachts is undeniable, both for the convenience of communicating and receiving intelligence under ordinary circumstances, and for its use in emergencies. But in either case the value is entirely dependent upon the quality and reliability of the in- struments and apparatus of which the equipment is composed. de Forest Radio Apparatus is everywhere conceded to be the finest available for private use. It has been developed and re- fined through the persistent efforts of Dr. Lee de Forest and his staff until it has reached a degree of efficiency which cannot be expected in ordinary amateur apparatus. Used extensively by prominent yacht owners and by U. S. and foreign navies. WIRELESS TELEPHONES OPENS UP A NEW AND INTER- ESTING FIELD FOR THE BOAT OWNER, requiring no spe- cial operator. Their perfection and practicability have been demonstrated beyond the shadow of a doubt. AUDION RECEIVING CABINET Write for free bulletins or let us recommend radio apparatus suitable for your requirements. $400.00 COMPLETE TYPE RJ16 -PRICE $150.00 TYPE 0J3- capable of trans- Incorporating in one cabinet the famous de Oscillion Telegraph, mitting the voice 15 miles, or telegraphic Forest Audion- Ultraudion detector and special transmitters \Audion Tuner. For spark and arc signals. messages 40 miles. Larger Most efficient receiving set ever offered at less for greater ranges. than $500.00.

FAMOUS DE FOREST AUDION DE- TECTOR TYPE RJ8 Three to five times more sensitive than any other known form of detector. (U. S. Bureau of Standards Report.) PRICE $25.00. DE FOREST RADIO TELEPHONE & TELEGRAPH CO. NEW AUDION AMPLIFIER FOR COMBINATION AUDION- 1391 SEDGWICK AVENUE, NEW YORK CITY INCREASING STRENGTH OF RE- ULTRIUDION DETECTOR Sole Makers of the Genuine Audion. Oscillion and the Highest CEIVED SIGNALS 25 TIMES. TYPE UJ2 -PRICE $30.00. Grade Receiving Equipment in the World TYPE EJ2 -PRICE $32.00.

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H. G ER N 5 B ACK EDITOR H. W. 5ECOR A5517CIATE EDITOR Vol. IV. Whole No. 47 MARCH, 1917 Number 11 Volcano - electric Plant Develops 15,000 Horsepower HE ocean waves give promise of rank folly to seriously consider such an Prince Gìnori -Conti on to his goal. As is some day furnishing vast quan- undertaking, yet we have ever to face the well known, in Central Tuscany, near Vol- titics of electric power, not to facts and Fact, remember, is often stranger terra, there are numerous cracks in the mention natural gas power plants, than Fiction. ground, from which powerful jets of very T wind motors, and a host of oth- The actual harnessing of an Italian vol- hot steam spout high in the air with great er more or less available and controllable cano to an electric generating station of violence and constancy, bringing up boric

r" COOLING

#-- CANDOUR

x - CVOOk- WISH VOLTAGE 5 ?EP-UP TRANS II BOI LE-Ft CO-ONTAINING WATER TRANSMISSION UNES `k TURBOGENERATORS

EXHAUST STEAM TU BORAX PLANT SUPER -HEATERS

T»i NATURAL STEAM

PIPERIVOLCANI6

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A Volcano- electric Plant Developing 15,000 Horsepower Is a Reality in Italy. This Plant, Now in Operation, Utilizes the Heat in the Natural Steam Pres. enfin the Ground Near the Volcano to Heat Water in Boilers. Steam from These Boilers Drives the Turbo-generators, the Electric Current Being Trans. mated Many Miles Away. sources of natural energy, but who would far -reaching usefulness is described by Pro- acid -which is very valuable-and other ever dream of harnessing a VOLCANO (or fessor Luiggi in Engineering of London. mineral substances of less importance. rather volcanic heat) to an electric gen- The ever -increasing cost of coal in Italy These powerful jets of superheated steam erating plant developing thousands of was one of the principal incentives that are called Soffioni -the blowers -and have horsepower? Verily, it would seem like ever goaded the brilliant and original been utilized for many years in the pro,-

www.americanradiohistory.com 790 THE ELECTRICAL EXPERIMENTER March, 1917

duction of boric acid and borax, and occa- MONSTER SEARCHLIGHT TO COUNCIL OF NATIONAL sionally for warming the houses in the GUARD U.S. SHORES AGAINST DEFENSE. nearby village of Larderello. The larger AERIAL ATTACK. In an act making appropriations for the proportion of the steam, however, is lost, A gigantic searchlight of 500,000,000 can- support of the Army for the fiscal year 1 having no local application, and with it is dlepower has been installed by the Govern- 1917, Congress established a Council of Na- lost its very valuable heat. ment on the aviation field at Hempstead, tional Defense for the coordination of in- Prince Ginori- Conti, the president of the L.I., N.Y., and it will shortly be put to tests dustry and resources for the national secur- Società Boracifera di Larderello, was the to determine its worth as a watchman of ity and welfare, and designates the Secre- first, in 1903, to try to utilize this super- our shores. Aviators will go up in bi- tary of the Navy as a member thereof. It heated steam for the production of motive planes, followed by "enemies." The search- is contemplated that this council will even- power. light will then find the "enemies" and the tually take over the work of industrial Elaborate experiments which were made other machines, hidden by darkness, will preparedness now being done by the Naval very accurately demonstrate that each bore attack and destroy them. The light has a Consulting Board, and arrange it in such can provide steam at a temperature of at radius of four miles, sufficient, it is be- form as to be available to all departments least 150 deg. C., and at the rate of from lieved, to pick up a machine and keep it of the' Government in time of emergency. 15,000 to 25,000 kg. per hour, that is, prac- within its arc, while anti- aircraft guns and The excellent work already done by the tically, from about 1000 to 2000 theoretical aeroplanes pick it out and destroy it. The Naval Consulting Board has been recog- horse -power per hour. Thus near Lar- accompanying photo shows the new search- nized by the President in the appoint- derello there is the possibility of develop- light as erected at Hempstead. ment of Mr. Howard A. Coffin, chair- ing motive power up to thousands and man of the committee on industrial pre- thousands of horse -power. Encouraged paredness of the Naval Consulting Board, by these results, Prince Ginori- Conti, in as a member of the advisory commission 1906, applied the steam to an ordinary nominated by the, council composed of steam engine of about forty horse -power. Cabinet officers. The act provides that The experience of several years has the advisory commission be composed of shown that this arrangement works seven persons, each of whom shall well so far as the mechanical power have special knowledge of some in- of the steam is concerned, but that dustry, public utility, or the develop- the borax salts and the gases mixed ment of some natural resource or be with the steam -especially sulfuret- otherwise specially qualified for the ted hydrogen and traces of sulfuric performance of duties thereinafter pro- acid -have a corrosive action on the vided, and also provides that the spe- iron parts of the engine and are the cial knowledge of such commission cause of frequent repairs. This dif- may be developed by suitable investi- ficulty was finally avoided by applying gation, research and inquiry, and made the superheater and afterwards used available for the use of the council. for driving but to 'a boiler; that is, by It is also stated that the work of the applying it instead of fuel to an ordi- Council of National Defense will con- nary multitubular boiler in which steam sist in the coordination of military, in- was produced at a pressure of two at- dustrial, and commercial purposes; in mospheres, then past thru a super- the reclamation of highways, railroads, heater, and afterwards used for driv- utilization of waterways, and employ- ing a 300 horse -power condensing ment of military and naval resources steam turbine, directly connected with for defense; and the increase of do- a three -phase electric generator, which mestic production of articles and ma- supplies the works and the villages Photo Copyright by Central News Photo Service terial essential to the support of the Larderello. This installation Gigantic 500,000,000 Candlepower Electric Searchlight population, both military and civilian, around Recently Erected at Hempstead, L. 1., by the U.S. Gov- had been at work quite successfully ernment to Guard Against Hostile Aerial Attacks. It in time of war. The superiority of the for several months when the present Has a Radius of Four Miles. foreign military machines is directly European war started. Then, coal be- traceable to such co- operation. coming very scarce, and prices rising up to prohibitive limits, the possibility of us- with the turbine; by this arrangement cor- WIRELESS 'PHONE FOR 'HOTEL ing on a large scale this natural steam rosion is completely avoided. This was PLAN. the real and chief difficulty to be overcome. became very important. Guests at the Hotel Oakland, of ,Oak- Prince Ginori -Conti considered it his duty The three -phase electric current is gen- land, Cal., may be able to talk by wireless to carry out this trial on a large scale, avail- erated at 4500 volts and 50 cycles per sec- telephone with friends on incoming steam- ing himself of his long and successful ex- ond, stept up thru an oil transformer to ers, if present plans under consideration by periments. Acting on the advice of the 36,000 volts, and sent along aerial con- the hotel management are carried out. Tosi. Works of Legnano-specialists in ductors to Florence, Leghorn, Volterra, Following the precedent by many hotels steam turbines and alternating current elec- Grosseto and many smaller towns of Tus- on the Atlantic coast, of installing wire- tric generators -he ordered three groups cany, to be principally used as motive pow- less telegraphic sets for the benefit of of condensing turbo- electric engines, each er for munition works during daytime and guests, the management some time ago took of 3,000 kw. (4,000 H.P.), working with partly for lighting purposes at night. up the feasibility of having a similar serv- superheated steam at PA atmospheres, gen- One of the 3000 -kw. units has been at ice installed in the Hotel Oakland, to, be erated in specially constructed multitubu- work since January, 1916, the second since operated in conjunction with the ocean lar boilers, the latter arranged vertically April, and the third has just been started. liners. and with aluminum tubes, both for better So far, the first two groups have worked Recent negotiations by the federal gov- utilization of the heat and better resistance quite successfully and have been a great ernment with certain interests who have to the corrosive action of the natural steam boon to the industries of Tuscany, greatly been developing the wireless telephone for from the Soffioni. This steam, it should crippled by the scarcity and high price of direct communication over the air route, be noted, is used instead of combustible; coal. This very successful harnessing of together with experiments which Uncle it loses part of its heat in the boiler, re- volcanic heat to an electric power -house Sam has been conducting with radio -tele- ducing its temperature from 180 degrees C., can be increased practically to hundreds of phonic systems, has led to the decision on to about 120 degrees C., and is then utilized thousands of horsepower, as the region of the part of the manager, Mr. Carl Sword, for the borax industries. Soffioni extends for many square miles to consider the practicability of having a The steam thus generated in the boilers around Larderello. wireless telephone establisht in the hotel. and used for the turbines is ordinary water Thus we see how apparently uncontrolla- The plan includes a co- operation among steam, which, on its way to the turbine, ble forces of nature have been tamed and hotel managers all along the Pacific Coast passes along aluminum pipes heated outside harnessed to do the work of man. In for the purpose. A regular service for the by a current of superheated natural steam America we are still in command of large transmission of important inter -hotel busi- at 180 degrees C., and thus gets in its turn coal deposits, but hydro -electric devel- ness, advance reservations by guests over superheated to about 150 degrees C. Af- opments are fast becoming a highly profita- the air, and a thousand other uses could ter passing thru the turbine this steam is ble and paying investment. But when these be found for the convenience. The plan discharged into a surface condenser, the have reached their limit, we may have to was suggested at the national meeting of circulating water of which is in its turn look to the ocean waves, and yet again fu- the Hotel Men's Association' held last year, cooled in an ordinary cooling tower, as ture generations may witness the sight of but no active steps were taken. shown in our accompanying illustration. electric power plants deriving their energy Under the plan, as outlined at the pres- The condensed steam from the turbines is, from the heat of the earth thru long steel ent time, the various hotel managers of the of course, pumped back into the boilers, and pipes sunk down thousands of feet. In the coast would form a wireless association thus no natural steam ever comes in contact light of modern science it seems possible. which would install apparatus.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 79f 20,000 Leagues Under the Sea NE of the most spectacular mo- The story opens with Uncle Sam, about oners by Capt. Nemo and upon their prom- tion picture features produced the time of the American Civil War, send- ise never to leave the undersea boat, they lately is the dramatization of ing out a frigate to destroy a certain "sea are accorded the freedom of the ship. The Jules Verne's "Twenty Thousand monster" which had been reported from name of the strange craft is the Nautilus Leagues Under the Sea." time to time in the various oceans, and and this original boat lias been carefully 0For many years attempts have by the moving picture people at been made which monster had supposedly done great reproduced to reproduce this masterpiece on the stage damage to ship- as well as by motion picture reproduction. ping. No one However, science had not developed far had been able enough, until quite recently, and hence all to kill the sup- previous attempts failed. Only a short time posed monster ago, due to the several inventions of the and for that well -known Williamson Brothers, has it reason the been possible to actually take moving pic- American frig- tures under the sca, and the present pic- ate manned by ture is a direct result of the Williamson a capable crew Brothers' untiring work along these lines. as well as by It is well known that forty -seven years several adven- ago, when Jules Verne wrote his book in turous people which he prophesied the submarine down to including t h e

Above: -Captain Nemo and His Doughty Crew Aboard the Submarine Nautilus,' Made Famous by Jules Verne in His "20,000 Leagues Under the Sea," and Now Reproduced in the Latest "Movie" Bearing that Name. Left: -Here We See Several Members of the Crew of the "Nautilus" Emerg- ing Thru a Sea Drop Door to Walk on the Sea -bottom. Note the Comprest Air Guns. Below:Sailors From the "Nautilus" Have Here Caught a Gigantic Turtle. The Men Carry Independent Comprest Air Tanks on Their Backs.

the most minute details, he met with quite French Profes- a good deal of ridicule, due to the fact that sor M. Arro- the world at that time had not advanced far nax, was sent enough to appreciate his efforts. It is the out to effective- old story of a man ahead of his time show- ly deal with the ing the world something which as yet exists new terror. only in his own imagination. When the frig- The new film which is now being shown ate finally meets all over the country and which has cost over the supposed a quarter of a million dollars to produce, is sea monster all undoubtedly one of the greatest spectacles efforts to kill it ever put before the public. are of no avail, While of course it has not peen possible but to the con- to show the entire action as laid down by trary the mon- Jules Verne, it is surprising how close the ster rams the ship, pitching M. Arronax great expense and regard for details. picture people came to reproducing Jules and his companions into the sea. When Capt. Nemo, the main character of the Verne's idea in its entirety. While it was they come to their senses, they find them- story, is shown in one of our photographs necessary here and there to embellish the selves on the back of the monster, which with his crew on the deck of the Nautilus. story with new ideas, this has been accom- they discover is made of steel, this being The latter, constructed by the Williamson plisht in a clever manner all the way thru. the famous Jules Verne's submarine, com- Brothers, is in itself a thoroly seafaring There have been some additions which manded by the mysterious Capt Nemo, machine, equipt with all the various kinds might have remained out of the picture, who supposedly has a grudge against hu- of air tanks for submerging and raising it, as, for instance, the firing of the torpedo manity and has sworn not to return to land and is propelled by powerful motors equipt which Jules Verne had not provided for in but roam the seas until his end. M. Ar- with storage batteries. As mentioned be- his Nautilus. ronax and his companions are made pris- (Continued on page 831)

www.americanradiohistory.com 792 THE ELECTRICAL EXPERIMENTER March, 19t7 Shooting Big Game on the Electric "Movie" Target THE motion picture camera has is secured to enable the moving picture three and one -half inches, electrically. penetrated the distant jungles so hunter to know whether his shots have There are 33 wires stretched horizontally often that it is the daily experi- gone true or not. across the screen, evenly spaced, and 33 ence of the movie "fan' to fear- This effect was accomplisht by the won- wires arranged vertically. At the many lessly stalk big game across the derful invention of Elliot Keen, an inventor points where these wires cross are the con- screen; to see the Rocky Mountain goat of New York City. The basis of this de- tact- making balls. It will, therefore, ¢e cavort on the spot where Charlie Chaplin vice is a number of cast-iron balls hanging seen that a bullet striking against the tar- so lately fell, is now a common occurrence, f rom a short piece of chain back of a steel get will connect certain two wires and as The grizzly bear and the Bengal tiger are screen, as seen in the upper right photo, the latitude and longitude lines upon the equally familiar to us. On the face of this steel screen the pic- map enable us to establish exactly any given

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tipper Left:-Front View of Marvelous Electric, "movie" Shooting Gallery, Where One Can Practise Hitting Moving Game. Upper Rights -Back of the Picture Screen: If Your Bullet Makes a "Hit," It Moves One of the lODO Balls Shown, Closing an Electric Contact. Lower Left-- Appearance of Special Motion Picture Projecting Machine, Fitted with Numer- ous Electrical Contact Fingers. Lower Right: -Close View of Rifles, Eacfr Equipt With Electrical Contact. Note Lamp "Score" Board on Beam.

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It was therefore inevitable that some one ture is thrown from a regulation moving location, so the connecting of one vertical should supply the missing link, so that picture projection machine, Each ball is and one horizontal wire establishes accu- the big game hunter, or even the amateur so arranged that when the bullet strikes on rately the point where the bullet struck up- marksman, could continue his sport, using the opposite side of the screen the ball on the steel screen, the pictured game for his target. makes an electrical contact and so identi- It is evident that if only those wires It is a very simple matter to take a steel fies itself on an annunciator, which cross beneath the picture of the ani- screen and, painting it white, throw a pic- There are about one thousand of these mal be connected with the battery then ture upon it and then with a rifle shoot at balls behind the screen. The balls are so stray bullets will be ineffective. the animal moving in the picture. But there placed that the location of the point of im- If for a moment we consider the bird in is little satisfaction in this until some means pact of the bullet is establisht within the picture as not moving and shown ex-

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 793 actly in the center of the screen, it will be ated by a commutator connected with the consists of one circuit which is broken in easily seen that the sixteenth wire hori- projecting machine. three places -one at the gun, one at the zontally, and the sixteenth wire vertically, It will be seen, therefore, that with the projection machine and one at the steel must be connected with the battery in series device thus far described, a man shooting screen. If, when the trigger of the gun with the bell or signal. The bullet, directed at this moving picture with a rifle would closes, one of these breaks and the bullet by the marksman and which hits the bird, succeed in ringing the bell every time he at the screen closes another of these breaks, will actuate the suspended ball and close hit the pictured image. Inasmuch as pub- the projecting machine closes the third by the circuit between these two wires, thus lic shooting galleries oftentimes have sev- connecting the battery to the essential wires, eompleting the circuit momentarily so that eral persons shooting at the same time con- then a hit has been made. the signal indicating a hit will be given. fusion might result as to who made the hit In spite of the fact that this is a some- This is accomplisht by means of a lamp, when the hit signal sounded. Therefore a what complicated machine, having cost placed in front of the gallery as seen in the special device has been designed which $27,(1011 for its initial trial installation, it has lower right view. keeps the scores of the individual marks- been found to stand up very satisfactorily When the bird starts to move the illu- man. under practical use. The most bothersome sion will be produced by the movement of The basis of this device is a small con- feature has been found to be the inaccuracy the film, or the situation which existed in tact placed on the rifle itself which is made of the film itself, which changes its dimen- the still picture will be changed every six- when the trigger is pulled. This moves a sions when exposed to the strong arc light teenth of a second. Therefore, some means brush electrically by means of an escape- needed to project the picture. must be provided to connect the proper two ment over the terminals of a number of To overcome this a very delicate framing wires with the battery for each location lamps. The other terminal or ground wire device was installed which framed the establisht by each picture passing thru the from the lamps is connected with the sig- fingers up and down to compensate for the machine. nal circuit, so that if the signal of a hit contraction and expansion of the film and To accomplish this the film is perforated came at the exact period when the brush for the wear on the sprocket holes, etc. before being used in the gallery, while on of the escapement released by the trigger To prove the accuracy of the device, the the projecting machine there are arranged was sweeping over the terminal of the inventor has adopted a peculiar bullet, car- a number of fingers, operated by a cam to lamp, the lamp would be lighted; if no sig- rying in the point a small amount of flash drop upon the film during the period when nal came from the screen immediately af- light material. The action of this bullet is the picture is shown on the screen. These ter the trigger was pulled, then the brush to show a flash of light, which identifies fingers are raised to permit the film to would harmlessly sweep over the lamp ter- the exact point of contact, thus showing move. When the film comes to rest and the minal and the lamp would remain dark. the gunner the exact position at which lie steel fingers drop upon it, two of the A cord connects each rifle with the mech- has aimed. fingers pass thru the previously made per- anism, and it has been found that six rifles To have these 33 horizontal wire termi- forations and thus connect the two essen- can be fired simultaneously at a moving nals and the 33 vertical wire terminals tial wires to the battery. This part of the picture, with practically no error in the each represented by a finger, or 66 steel projecting machine can be seen in the lower score, altho it will be evident that there is fingers to be raised and lowered each six- left photo. a short time element and if two rifles fire teenth of a second upon the film, was found During the period when the picture is together and only one makes a hit, then to be impractical, because of the fact a sin- moving the bullet might, and likely does, both will receive credit. The upper left il- gle picture on a moving picture film is but strike the screen. It was, therefore, nec- lustration shows the general arrangement three -quarters of an inch wide and altho essary to establish a secondary means of of the electric shooting gallery as used in the horizontal fingers occupy one side of keeping the two proper wires alive, even one of the amusement places in New York the film and the vertical fingers occupy the tho the screen was in the dark. To do this City. other side of the film, to place 66 such fin - a number of relays were introduced. actu- The electric moving picture target simply (Continued on page 851) "WIRELESS" MOVIES VERY radius of many thousands of miles. "I guess it was a sort of 'call of the POPULAR. We quote Mr. Sill's amusing remarks: spark.' The "Honor System" photo play pro -, "As a kid," says Mr. Sills, "I had two "When I was eleven-that was in 1893 duced by the Will- -the World's Fair iam Fox Corporation was held in Chicago. and just recently re- Dr. Charles P. Stein- leased, foreshadowed metz, the electrical last summer, in its wizard, delivered an first presentation, re- address in one of the markable achieve- buildings, and con- ments in the scientific cluded with an offer field, which have to answer any ques- since come to pass. tions put to him by Wireless communi- the audience. cation between the "I asked the first United States a n d and was so bent on Japan, which has al- getting more infor- ready been effected, mation on my- pet was foreshadowed in hobby that I just re- this presentation, and fused to let up and scenes were taken put one query after showing the imagi- another to him. Those nary wireless feat in in the audience must progress. have felt that I was a The story runs thus nuisance at first, but -Joseph Stanton, a I suppose they gradu- wireless inventor, who ally carne to under- has been a student of stand that it was just electricity for many my enthusiasm. years; is the hero. It "Steinmetz finally is his dream to effect laughed and said wireless communica- from the platform tion between the Uni- that he would be glad ted States and Japan, to spend an evening and, indeed, this did with me. Then he prove, later, one of walked right down his crowning the aisle to where I achieve- A Thoughtful Moment From the Film -Drama "Honor System " -in Wh ich the Scientist -Hero ments. The part is Becomes Blind Thru His Radio Researches. sat and shook hands played admirably by with me." Milton Sills, who is himself a scientist of inseparable companions. The father of one The film play proceeds further into vari- considerable attainment, and a graduate of was a lineman for a telephone company and ous interesting episodes, but ends quite the University of Chicago. the father of the other was superintendent touchingly. Near the close of the invent- We are introduced to wireless apparatus, of a big power house. or's career, he meets with an accident of the hero's own make, which, tho cap- "The whir of the electrically propelled which blinds him forever. And we get a able of transmitting but a short distance, machinery just seemed to get into my sys- last glimpse of him with his sweetheart is equipt to receive messages within a tem. reading to him.

www.americanradiohistory.com 794 THE ELECTRICAL EXPERIMENTER March, 1917 Traveling at 500 Miles Per Hour in the Future Electric Railway AN electric railway over which pass an alternating (rapidly changing from in length, if it had to be equipt with such cars will fly at the astonishing positive to negative and vice versa) current a series of closely spaced, powerful elec- speed of 500 miles per hour, or at thru the magnet coil, it will produce, in tro- magnet coils. the rate of 8.3 miles per minute, turn, an alternating or constantly changing As is well known, it is possible to ar- is one of the scientific possibilities magnetic field. Such a field will repel range an electro- magnet of proper propor- of the day and one which is engrossing sheets or rings of copper or aluminum, tions between two horizontal aluminum some of the master engineering minds of owing to the Eddy currents which are set plates, and when excited by an alternating two continents. up in them, the phase of these eddy cur- current, It will he found that the reaction An electric railway having such possi- rents being retarded by their self- induc- of the magnetic flux set up will lift the bilities was broached by Professor Boris tion. Hence, if we have an electro -mag- magnet coil above the lower aluminum Petrovik Wein- plate, and also berg, Instructor cause the upper in Mechanical 60r4roi/ stipp rt rings aluminum plate Engineering at s_.r, to be levitated, t h e Imperial dr raised above of [aül' 'iieoiu the coil. University f/ectric feed Petrograd. Rus- wires Here is t h e sia, at the re- Direction of cor germ of a re- New York v o 1 u tionizing cent Sheet Shoe kW/ay/nag/Jet cods meeting of t h e Storage Bo//erg idea, viz., why American As- fled lights n o t transpose sociation f o r t h e conditions in Bachelet t h e Advance- Car the m e n t of levitated r a i 1- Science. Pro- way system, fessor W e i n- and instead of berg has even lining the track built a model with millions of his proposed of dollars' 500 mile per worth of elec- hour electric tro - magnets, railway; but Guide Guide simply place the roi/ rai/ t/otormons Iron rodIneorsfa/ioasr Levitating levitated mag- the first diffi- cab. Aluminum inductor culty met with moymis nets within the in considering car and con- h i s really re- struct the low- able in- er rail of prop- mark Quite Likely Be of the Levitated Type, as Here vention is Fig. 2. -The SOO Mile Per Hour Electric Railway of the Future. Will erly spaced that Illustrated. Powerful Electro- Magnets Within the Car Raise It Above the Track, while Properly Spaced Solenoids the cars a r e Pull the Car Along. aluminum in- supposed to be ductor sections? shot thru a tube in which there is created net M, excited by an alternating current as By this means it becomes more feasible to a partial vacuum. in Fig. 1, and if we hold lightly an alumi- construct such a levitated railway and at It would seem quite prohibitive, at least num ring R, just above the pole of the mag- various points along the railway suitable with our present understanding of such en- net, we find that the alternating magnetic ring- shaped solenoids or hollow tubular gineering matters, to build even a relatively field will react in the manner just de- electro- magnets are placed to propel or pull small railway of this type and capable of scribed, and forcibly repulse the ring up- the car forward. maintaining such a speed as 500 miles per ward, causing it to assume the position in- The accompanying diagram, Fig. 2, hour where the cars would have to pass dicated by the dotted ring. shows several details of the levitated elec- thru an evacuated tube or tunnel, even if Again, if the aluminum ring is held by tric railway which the editors believe this were divided into short sections or four cords and the alternating current past would work out successfully, if the engi- locks, so as to reduce the total quantity of thru the magnet coil, the ring will remain neering details are properly taken care of. air that would have to be pumped out of floating in space above the magnet as The car itself is patterned after the mod- the tunnel at a given instant. If we had shown. ern Zeppelin flying machine, having the available to -day a system extending from In the Bachelet system of levitated loco- front end in the form of a hyperbola and New York to San Francisco and on which motion, there is involved a fundamental dis- the rear end tapered off, so as to offer the the cars traveled at the rate of 500 miles advantage, which rapidly assumes alarming least possible resistance to the air as the per hour. then the trip between the great proportions when one comes to consider car shoots forward at the rate of 500 miles Metropolis of the East and the Golden Gate building a commercial railway of this type. per hour. A series of powerful levitating could be made in five hours. In other This disadvantage lies in the fact that the electro-magnets are mounted under the words one could breakfast in New York cars, made of aluminum or having suitable floor and within the shell of the car as and lunch in 'Frisco! aluminum inductor plates mounted under- shown. A' high tension alternating cur- Many other remarkable possibilities rent is supplied over feed wires car- of such a railway system will immedi- ried on cross arms at the top of the ately suggest themselves to the reader. tubular track system, and this current The editors of this journal have could be taken into the car thru spe- evolved a system for ultra high speed cial contact shoes or wheels on either railway locomotion, such as 500 miles side of the car body; this alternating per hour, and which has been por- current being used to excite the levi- trayed vividly by the well -known ar- tating magnets for lifting the 'car tist, Mr. George Wall, on our front from the track. cover. This system does not involve The road -red is built up of a spe- any such hyper- scientific proposition cially designed aluminum inductor as that requiring an evacuated tube rail, with a lower sub-rail of iron at thru which the cars are to pass, but, station approaches. A small storage instead, brings into play the rather Fig. I.- Demonstration of,the Levitation Phenomenon Occurring battery could be carried at the rear When an Aluminum Ring Is Placed Over an Alternating Current of the car so that in slowing down slightly known method of eliminating Magnet M; the Ring R being Repelled Upward. friction by electro-utagttetie levitation, or stopping, and instead of exciting the on the principle developed to some extent a neath them, are intended to be levitated or levitating magnets with alternating current few years ago by one Emile Bachelet, for- raised into space, so as to eliminate me- they conk], be charged with direct current merly of Mt. Vernon, N.Y., but now en- chanical friction between the cars and the from the storage battery and thus a great- gaged in research work in England. track, by a contiguous series of powerful er frictional effect produced between the The underlying principle of electromag- and expensive electro- magnets spaced moving car and the rail. The flux from netic levitation, as followed out by the evenly along the track and just below it. the electro- magnets within the car would, Bachelet floating railway system, is readily It does not require a great deal of cal- in this case, react on the iron sub -rail. it The car would be propelled forward in a understood by referring to Fig. 1 here- culating to arrive at the conclusion that we an electro- magnet coil would cost a small fortune to build such a manner similar to that of Bachelet's, or by with. Here have on page 851) M and an aluminum ring R. Now, if we railway even if it were only a few miles (Continued

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 795 An Electric "Movie" Machine for the Home NE of the greatest objections to the right. The face of the bulbs is directed the light is focused upon the postcard and tur standardm in type pic- towards the paper film so that the light reflected thru the lens. It will be noted that ture machiue for the individual falling upon it is reflected towards the pro- the general make -up of the projecting ma- user is that it employs a celluloid jecting Ichs, which is stationed on the front chine is just the reverse of the commercial O filin with considerable expense at- of the chamber. A photograph showing the ones used to -day. The light is focused tached thereto, as well as the fire danger of exact construction of the luminous unit is on the picture in the opposite direction to this inflammable article, thus barring it reproduced at Fig. 2. The central opening the projected image, while the light of the from use in homes. schools, etc. How- is used to permit the reflected picture to present standard machine is focused in the ever, this has recently same direction as the been overcome by a 61 projected screen im- Xew York genius, Mr. age. Fig. 4 shows a H a r twell different type Webb, who projector in- has spent a . tended prim- number of arily for the years in de- home. The veloping a n picture is fo- entirely n e w cused on a motion pic- t r a nsparent ture appara- , creen, the tus. The lim- photo reel be- i t a t i o n s in g operated above cited by a motor. are at once The nega- overcome by tive, which is this new in- t h e original vention, which ph o t ograph is based upon taken of t h e the fact that moving oh- paper is ject, is first cheaper and made on a far safer than regulation cel- celluloid film; luloid film aside fro m and taken this it will with a stand - produce a'no- ard moving tion picture picture e a m- of equal qual- era. The con- ity. It can be struction of handled by a the new in- child as w e l l s t r u ment is as by a pro- very simple as fessional seen from the operator. For accompanying i n fi ammable photograph. fi 1 m exposed Standard mo- to the a r c t o n picture light, it sub- negative films stitutes paper are used, a n d films, exposed the camera 100 to the mild 1. carries rays of the in- feet of film, ca n d eseent ra being so con - bulb light. strutted that For the ex- it may he pensive cellu- loaded in loid film it broad - d a y- substitutes an light. T h e paper fi I in may be operated inexpensive 1;11_11.1111; +IEEE strip, involving no fire at will either by the risk and which may be Illustratnons Above S how: I -the Projector; 2 -the Lamp Ring; 3 -the Camera; 4- "Home" u s u al hand -crank or left about the house Type of Proiec tion Machine and 5 -a Typical Strip of Paper Film (the Border). by merely pressing a or shipt thru the maiL button. which closes The adoption of a paper tape or strip pass thru and enter the projecting lens. The the circuit to a tiny, concealed electric mo- for projecting work necessitates the use general operating principle of this machine tor, driven from dry batteries carried in of a somewhat different projecting machine, the pocket of the operator. The connec- as the light cannot penetrate the paper film tions are obtained by means of a flexible sufficiently to show the image clearly on the conductor, fitted with plug connectors at screen. Therefore, it was necessary to in- both ends. In this way it can be operated vent a new illuminating scheme for this without a tripod, a great advantage in kind of work, and it was not long before emergency use. Mr. Webb evolved one which has proven After the pictures have been photographed very successful. One of the latest type of upon the film, the latter is developed in the projecting machines is illustrated at Fig. 1. usual manner and the print is made upon a Its general construction is very similar to sensitized paper strip, which is used in pro- the present type moving picture machines, jecting the picture on the screen. A sam- the only difference being that the film is ple of such a paper strip is shown as a illuminated as stated above. border about the photos herewith. The gen- By referring to the first photograph, it eral make -up is about the same as for reg- will be noted that the paper film is held ular movie films with the difference cited on the top reel and is taken up on the lower above. one, when in operation. Similar gears are It is at once apparent how universal are used for feeding this photo strip, as in an the uses of this wonderfully developed cam- ordinary machine. The source of light is Diagram Showing How the Light is Reflected on era intended for Mr. Everyman and his a the Paper Film, and the View Projected Thru the familj. The amateur may take his own obtained from number of incandescent Lens Onto Screen. electric bulbs, placed in reflectors and ar- pictures, print and develop them in his dark ranged in circular or ring form. This unit is exactly the same as that of a postcard room and project them on his parlor wall. is placed in the circular chamber as seen at projector, with which we are all familiar, (Continued on page 83f)

www.americanradiohistory.com 796 THE ELECTRICAL EXPERIMENTER March, 1917

HOMEMADE ELECTRIC VAPOR other part of the boat to become invisible a little to get the right shades of (glaring) BATH. at even short distances. green and violet, but you will obtain sur- Vapor baths and also plain sweat baths This, however, has been proven to be in- prising results eventually. are often highly beneficial. If one pro- correct by no less a genius than Mr. Wm. In demonstrating this wonderful scien- vides a suitable rubber cloth (or blanket) A. Mackay, a mural decorator of New York tific principle, Mr. Mackay took a large cover to cover the body, as shown in the City. Mr. Mackay recently delivered a lec- board which he had previously prepared, accompanying illustration, advantage may ture to the officers of the U.S.S. Tallahas- moved it to some distance from his guests, be taken of this treatment at small ex- see, and he explained his and held it up for their inspection. "What pense. First we may use the ordinary technique of rendering the color does this board seem to be ?" he electric sad iron, suspending the iron on periscope invisible in simple asked. All were certain that it represented a hook beneath the chair. This will give language. Said Mr. Mac- a beautiful sea blue. This blue board was the patient a good sweat. A toaster or kay: "The thing to do, evi- then taken out on a boat some distance other small electric stove will serve this dently, to make the periscope away and suspended above the deck, with purpose very nicely. By placing some invisible, would be to paint the ocean as a background. It actually be- medicating, vaporizing fluid in a small that object the color that came invisible! Even t a short distance, vessel and then heating this solution by most resembled the water. not even an outline of it could be observed. immersing an electric But it seems that such is not Thus, if it had been the periscope of a sub- water heater in it, a va- the case. marine, it would have insured the crew and por bath will be had. It If one takes up some of officers against attack, as surely as if they will be found extremely the sea water in his hand and exam- had been concealed under 50 fathoms of efficacious to employ one ines it closely, he will at once per- water. of the well -known Vap- ceive that it is not blue at all, but After the performance the board which orel devices for this pur- quite colorless and translucent -ex- had appeared sea-blue to all was shown to pose, which require but actly similar to the water you drink the audience at close range. It was not sea - little current, while they from a spring or well. It has been blue now, but it was painted in checker- rapidly vapor- ascertained by scientific analysis that board fashion in a vivid green and purple, ize, by elec- the blue of the sea is composed of as schematically indicated in our illustration. trolytic action, nothing more or less than light, and any kind of light is a combination of several medicant or primary colors. Under the peculiar DANCED TO WIRELESS MUSIC disinfectant. conditions obtaining at sea, two of SENT 31 MILES. Contributed these colors combine and the resul- Dancing to music transmitted by wire- by ALEX. K. tant vibrations in the ether cause our less was a novelty offered recently to guests CAMPBELL. brain to see blue. But this at a house party in the home, in Morris- ccfcrarc is not the blue that the ar- town, N.J., of Theodore Gaty. The music - RAT- tist paints on his canvas of was played in the laboratory of the de For- MON an ocean scene. That is a est Radio Company at Highbridge, New paint -the other is simply York, and was received at the Gaty home radiant light so arranged in on an instrument so delicate that it has its vibratory combinations as picked up radio signals sent from the Ger- to produce certain definite man government station at Nauen. impressions of color on the The fox trots and waltzes played thirty- optical machinery of the hu- one miles from the Gaty home were made man brain. sufficiently loud by a special amplifying de- To Take a Vapor Bath at Home, All You Require Is an Electric To cut the story short, Mr. vice. The plan was suggested after music Flatiron, a Vessel to Hold the Medicating Liquid and a Rubber or Other Blanket Arranged in the Manner Shown. Mackay made up a checker- sent from the de Forest laboratories had board affair, the alternate been heard by accident. Music has also THE PERISCOPE IS squares of which are painted come over the Gaty aerial from New Ro- THAT green and violet. The vibrations of these chelle. INVISIBLE. two colors, when HE submarine periscope is one of viewed jointly by the The receiver caught the sounds so dis- those small, yet all- important topics eye, would then attack the retina, and tinctly that it recorded remarks of the T upon which naval officers have been mixing, cause the brain to receive an im- sender and the grinding of the spring as the wont to argue for some time; or, in fact, pression of sea blue. phonograph was wound. ever since the submarine has become an up- This remarkable scheme is shown in the Mr. Gaty and his two sons, one of whom to- the-minute factor in naval warfare. One thing we know, and that is that the subma- rine is running blind when it begins to sub- merge so deep that its periscope disappears beneath the surface of the water. It is often mentioned Ly naval people and others that, granting the point we have an invisible periscope; then with an observant officer on a torpedo boat, he will invariably catch sight of or spot the white trail made by the periscope in its course thru the water. Needless to say this has been the worry of more than one submarine officer. But the periscope is not always moving, nor need it do so. It often happens (as re- corded a number of times in the present war) that a submarine has been lying on the bottom of a bay or harbor for a num- ber of hours, and arising, it becomes desir- able to sight the bearings thru the peri- scope; in other words, there are many op- portunities for using the periscope where. if it were practically invisible, it would ren- der a submarine safe from attack by tor- pedo boats or scout cruisers, some of which can pounce down upon the sub -sea boat at a fifty -mile -an -hour speed. About every imaginable manner of paint- ing periscopes and submarine hulls has been tried out by the various Navies of the The Invisible Periscope Has Seemed to be an Elusive Myth but an Artist-philosopher of New world. It was long considered that, if the York Has Found That a Periscope Painted Checker-board F=ashion, as Above. with A ternating structure of the submarine or ship could Patches of Green and Violet, Will Become Invisible Even at Short Distances. be painted with a certain splashy forma- tion of sea blue and white, that it would illustration herewith. If you have not for- is a student at Cornell University, have very obligingly merge into the color scheme gotten how to dabble in water colors, try it made a hobby of wireless and have a very of the sea, and thus cause the periscope or out yourself. You may have to experiment elaborate plant.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 7'17 How Electro -Pneumatic Tubes Shoot Mail Underground THE accompanying views show re- supporting rail. The side rails act as apart in the tube, and there will be ten car- spectively a Monorail Car used guides only. riers in transit per mile of tube. The in- in a newly devised 30 -inch un- This automatically controlled electric itial air pressure is a constantly varying derground tubular railway; a railway has been designed to provide a quantity which depends upon the length of view from the skeleton track of means of underground or surface transpor- the tube, the number of cars in transit at the tubular railway, and the appearance of tation which will have a larger capacity any given time, and other conditions. the pneumatic mail transportation tubeter- than a pneumatic tube. The system is Speaking generally, however, we find that minals used in the Chicago General Post automatic in its control. After a car or for a' tube line about two miles in length, Office. train is started it maintains a constant the initial air pressure would be approxi- The rated power of the motor in the speed regardless Of grades or curves. Be- mately six pounds per square inch, or three Monorail car is 4 horse- power. The car fore the train is started a mechanism is pounds per mile of tube. This ratio, how- is designed for speeds between twenty and set on the first car, which indicates at ever, does not hold for any length of tube thirty miles per hour, but it is not limited what station the train is to stop. On ap- line, but is approximately true for the to these speeds. With a motor of suitable proaching the station this indicating de- lengths of line ordinarily used in the post - capacity, the car can easily attain a speed vice causes the train to switch off the main office service. of sixty miles per hour. As the system track to a siding on which the station is The specifications_of the United States

Top Left- Monorail Car as Lsed in New 30 -inch Underground Tubular Railway. It Takes Electric Current Thru Special Trolleys From an Insulated Conductor Running Along Just Above the Car. Rated at 4 Horse-power. Speed Attainable 20 to 60 Miles Per Hour. Lower Left -A Glimpse of the Electro-pneumatic "Mail" Tube System Used in the Larger Cities. The "Mail" Is Packed in Carriers, 500 Letters in Each One, which Are Shot Thru the Tubes at Precise Time Intervals, with a Speed of 30 Miles Per Hour. Below-The 30 -Inch Diameter Tubular Track System for the Mono- rail Electric Car Shown in Upper Left View. The Side Rails Act as Guides Only. Note the Insulated Trolley Wire at the Top. A Possible Forerunner of Future Electric Railway Systems.

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is designed, the cars can pass around curves located. The train quickly and positively Post Office Department, under which this of very short radius without danger of stops itself when in the station by a spe- pneumatic tube service is installed, call for leaving the track. The thrust due to cen- cial mechanism. tubes eight inches inside diameter. The trifugal force is taken directly by one or This system can be of any desired length. carrier or traveling container, when in- the other of the side rails. The size of the cars and the dimensions serted in the tube, is propelled at a speed The capacity of the Monorail car is well of the tunnels thru which they run may of thirty miles an hour as stated above, and shown by the man lying in it. The con- also be varied in order to provide for each carrier will hold 500 letters. The struction of the car is also shown clearly. the different kinds of service. It is par- tubes can transport 200,000 letters an hour The car is 4 feet long and 25 inches in ticularly suited for use under conditions in either direction. diameter inside. Externally it is 7 feet where a pneumatic tube would be of in- The Government experts estimate that 3% inches long, from buffer to buffer. The sufficient capacity, and where a trolley sys- every day 20,000,000 letters are advanced tunnel thru which it runs is 30 inches in tem of the usual type with attendants on by the pneumatic tube service. Twenty- diameter. Cars and tunnels can be made of the cars would be too large. eight hundred carriers are constantly in any size adapted to the material to be Many of the larger cities are equipt with motion traveling from one post -office sta- transported. pneumatic tubes, which connect the vari- tion to another thru the pneumatic tube The total length of the circular testing ous post -office branches with one another. systems. The authorized mileage of pneu- track at Cambridge, Mass., where the cars The mail, placed in special carriers, is shot matic tube service in 1898 was but 162 are tried out is 1,534 feet. The car travels thru the tubes by comprest air. This is miles, while in 1916 this figure had climbed around it at a speed of about twenty miles supplied by electrically driven and con- to 113.2 miles. One thing about this sys- per hour, requiring about one minute to trolled air compressors. tem of transporting mail rapidly is that, make the circuit, but this speed can be in- In these underground mail tubes, the car- there is never any blockage due to winter creased or diminished as desired by power riers have a speed of about thirty miles per storms, or street congestion. The push of controlling devices located in the station. hour and are usually dispatched at mini- a button, the hiss of escaping air, and your The current is led into the moving car mum intervals, varying from ten to fifteen letter, in company with 499 others equally thru T- shaped trolleys on the top, the cur- seconds. If dispatched in two minute inter- important, is shooting along under the rent returning thru the bottom rail. The vals and traveling forty-four feet a sec- streets and rivers with express train ve- upper rail is, of course, insulated from the ond, they will be approximately 528 feet locity.

www.americanradiohistory.com 798 THE ELECTRICAL EXPERIMENTER. March, 1917 Electricity and Life By FREDERICK FINCH STRONG, M.D. Lecturer on Electro- therapeutics. Tufts Medical School, Boston CIENTIFIC progress during the past nized this force; it is quite unorthodox to and frequency during some research work. three decades has perhaps surpast even suggest that it exists- simply because He prophesied that when electrical oscilla- that of all preceding ages; but we we have not been able to measure and re- tions were fully understood and applied by are still in the kindergarten class cord it by our still comparatively crude physicians that a universal healing agent when we compare what is known laboratory instruments. would have been obtained -one which with that which is still to be discovered. A few years ago, when almost every sci- would so increase the vital energy and re- To discover means prac- sistive reaction of the hu- tically the same as to un- man body as to enable it cover, implying that the to throw off all disease. truth or fact was there all The present writer, acting the time but was hidden, on this hint, constructed covered, occluded, or oc- a high -frequency apparat- cult; and is it not a fact us, tested it on a number that many of the electri- of patients and reported cal discoveries of to -day his results to a local med- would have been regarded ical society in 1895. So as supernatural or occult far as can be learned this by the scientists of a few was the first clinical work generations ago? Of ever done with the Tesla course there is nothing su- Current, altho d'Arsonval pernatural in the strict , in Paris was then experi- sense of the term, but menting with his rela- many things remain oc- tively low voltage cur- cult, altho science is daily rents, produced from 3,000 uncovering new and hith- cycle alternators. Later, erto undreamed -of mar- Apostoli, Denoyes, and vels. others reported remark- There exist great Cos- able results from the cur- mic Forces of which we rents induced in the bodies still know but little. Grav- of patients placed inside itation is one of these; we of huge solenoids or wire know something of its coils thru which high fre- laws and the results of its quency currents were pass- action, but nothing what- ing. The effects obtained ever of its real nature. Demonstrating in a Startling Manner, the Appearance of the Human (the Author's) were : increase of strength, Electricity is another; of Body When Charged With a High Frequency Current. This Picture Shows Exactly appetite and weight, induc- this we know somewhat How a Person Charged From a Powerful High Frequency Apparatus Would Appear to Our Unaided Eyes, Were They Attuned to Respond to Vibrations of One or Two Millions tion of natural restful more, and we now recog- Per Second, Instead of From 380 to 760 Million- Millions Per Second (the Range of Normal sleep, and increase in tis- nize it in a variety of Human Vision). This Display Greatly Resembles the Natural Aura Surrounding the sue combustion and dim- forms, as Human Body, but which Average Persons Can See Only by Gazing Thru Special Chemi- ination. light, heat, cal Screens. chemical action, magne- ) Early in 1895 the author tism, etc., but its true nature is still a entist was a materialist, we believed in devised the first Vacuum electrodes for ap- deep mystery. Life -force or vital energy nothing but matter and force; to-day sci- plying Tesla currents to the patient. To- is another great Cosmic Principle; thru its ence recognizes the necessity of a third day thousands of physicians are using this action electrons are formed into atoms, basic principle, Intelligence or Mind; with- device, often miscalling it the Violet -ray atoms into molecules, molecules into crys- out this we can satisfactorily account for Treatment. This is of course a misnomer, tals and chemical compounds, and these none of the facts of the world in which ' the violet light in the tube having nothing into the bodies of plants, animals and of we find ourselves. Its manifestations in whatever to do with the healing effect pro- matter thru the Cosmic Forces give us at least a working hypothesis of life. As electricity has been the great field for the investigations of the past century so will the nature and manifestation of the Life -force be the source of the discoveries of .tile future. Even to -day we may haz- ard a few statements regarding this hypo- thetical Prana or Vital -force. For exam- ple, it comes to us -like all other active forces -from the Sun. It is stored and transmitted by plants and by the oxygen of the air, and in the human body it ap- pears to be distributed thru the great Sym- pathetic Nervous System to every organ and tissue of the body. The Sympathetic nerves radiate from the Solar Plexus -our Sun- center. If bacteria or poisons inter- fere with this circulation, as for example in infantile paralysis, the muscles from which the supply of life force is cut off, lose their power of reaction and wither away. It is in this connection that we may study the action of certain electric currents as ap- plied to the treatment of disease. It would seem that certain types of alternating cur- rents of high frequency and voltage great- ly facilitate the distribution of this vital principle (Nerve- force, Prana, or whatev- Electrical Autograph of the Human Hand, Show- er you choose to call it), and this explains A Striking Electrical Autograph of the Tips of ing the Radiations from it When Charged with the action of one of the most valuable of the Four Fingers and Thumb of the Author's a Powerful High Frequency Current. Left Hand. A High Frequency Current Charged recent medical discoveries. the Hand while It Rested on a Photograph Plate, man. We have no name for this force, but In 1893, Dr. Nikola Tesla described in a With the Results Shown. thru its action the great Cosmic Scheme magazine article the remarkable effects up- of Evolution goes on. In India they call it on himself and his assistants resulting from duced by the transmitted electrical oscilla- by a Sanscrit name -Prana. Here in the their exposure to the action of alternat- tions. Occident we have not yet officially recog- ing currents of exceedingly high -voltage (Continued on page 831)

Z, 0 - 3 3 k- G.. www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 8oi Oxy benzylmethyleriglycolanhydride ITH a cunning surpassingo over extremely homogeneous, the same all Tensile Strength :average): 3700 to 4500 lbs. per sq. ìn. that of the alchemist of old, the way thru. Unlike many die -cast alloys, Colors: Dark brown, reddish brown and black. the modern chemist combines Bakelite does not lose its mechanical two strong- smelling liquids strength nor deteriorate with age. In a An important form of the insulator is to form a solid that is utter- critical time test with a gear made from known cominercially as Bakelite -Dilecto. ly devoid of odor or taste. Under condi- Bakelite- Micarta driven by a steel pinion, This hard, marble -like material, which is tions known to that deft magician -the practically no wear was evidenced after 20 much used for switch panels, especially chemist -those two odorous and unprom- months' service. The speed of the special on wireless sets where the very best of ising materials, carbolic acid (Phenol) and gear varied from 560 to 1100 r. p. In. insulation is demanded, has an average formaldehyde, unite and form a transpar- The new insulation in the form of sheets, dielectric strength of 700 to 1,150 volts per ent, amber -like solid (Oxy-benzyl- methyl- rods, and tubes is fast taking the place of mil (1 mil equals .001 inch) according to englycol- anhydride), better known as hard rubber, fibre, pressboard, and similar thickness. The insulation value increases BAKELITE. materials. It combines high dielectric somewhat at temperatures up to 212°F. Bakelite is a condensation product of strength and heat resistance with unusual Sheets approximately g inch in thickness carbolic acid and formaldehyde. In its mechanical strength. It is liard, tough and have been repeatedly tested in excess of final form it is a hard, amber -like sub- homogeneous and fairly flexible. Supplied 100,000 volts. stance, having none of the chemical char- in sheets, rods and tubes of standard sizes Bakelite -Dilecto will not expand, con- acteristics of the raw materials from which it can readily be machined to any required tract or soften under the influence of heat, it is made. form. Standard colors are brown and even up to the point of carbonization. It Bakelite has no melting point, but at black. is not inflammable, like hard rubber or temperatures in excess of 575 °F. (300 °C.) Telephone apparatus has benefited greatly resinous materials, but will eventually sup- gradually carbonizes and disintegrates. It by the advent of Bakelite. The acconl- port combustion if brought into contact with is not merely a mixture, like compounds of panying illustrations show a sectional view a flame for any length of time. It will, rubber, shellac, or resin, which have characteris- tics of their components. Bakelite is an Ameri- can invention, the pro- cess having been origi- nated by Dr.' L. H. Baekeland, already wide- ly known by his discov- ery of so- called gas -light photographic papers, no- tably Velox. Moulded Bakelite finds great favor in the electrical field as an in- sulating material-it is hard and strong, has great electrical resist- ance and successfully withstands high temper- atures. Water, steam, oils, solvents and most chemicals have no detri- mental effect on it. Exactness of shape and size is characteris- tic of Bakelite moulted insulation. Every piece comes from the die ex- actly like every other piece; the edges and lines are sharp and clean The Illustrations Show from Left to Right -Section of a Moulded "Bakelite" Telephone Receiver Shell; Process of Mould- and the piece fits in ing "Bakelite" Transmitter Mouthpieces, "A" Being the Hydraulic Press and "B" the Multiple Moulding Die; Upper Picture Shows Section of a Mouthpiece. place as in interchange- able machine construction. of a Bakelite receiver shell as well as a however, continuously withstand a tempera- Because of its permanence and chemi- section of transmitter mouthpiece. The ture of 300° F. without deterioration. It cal inertness, this new insulator is the ideal machinery shown comprises powerful hy- cannot be moulded but is supplied in a num- material for electrical instrument construc- draulic presses which press the dies to- ber of special shapeá for certain require- tion. No acid -sulphur compounds are gether and thus form the accurately shaped ments, such as sheets, rods and tubes. emitted as in the case of hard rubber, nor mouthpieces seen on the bench in front Regarding the insulation resistance of does Bakelite turn green, or bloom. The of the operative. Here "B" represents the Bakelite -Dilecto, the following data will finish, too, is all that can be desired -it die, "A" the hydraulic press, and "C" prove of interest. comes a from the mould with beautiful the moulded mouthpieces. FOUR SAMPLES TESTED,3. 16 INCH THICK. lustre and with every detail and relief The new Bakelite receiver shell is with- Normal Condition sharp and clean; o buffing is necessary. out a doubt the most perfect receiver shell Resistance of sample Specific insulation resist - This remarkable insulation meets every to -day. It is a great improvement over Megohms ance Megohms requirement for moulding in metal inserts. the old style hard rubber and composition per in. cube per cm. cube 1 37,000 530,000 1,350,000 The inserts are in to stay, securely and ac- shells and has none of the disadvantages 2 30,000 4540,000 1,110,000 curately positioned when the piece comes of either. It will not turn green from age 3 29,500 425,000 1,080,000 from the mould. To put metal inserts in 4 29,000 420,000 1.070,000 or lose its lustre. It will last indefinitely, After heating at 104° F. for 24 hours. hard rubber or fibre requires drilling, tap- which helps to reduce maintenance cost. 1 260,000 3,700,000 9.500,000 ping, and fitting -slow and expensive pro- Not only are the receiver shells made of 2 102,000 1,500,000 3,800,000 cesses. Moulded Bakelite can readly be this but mouthpieces and cer- 3 190,000 3,750,000 7,000,000 material the 4 128.000 1,850,1100 4,700,000 machined and polished. Each of the stand- tain other parts are made of it as well. It is vitally interesting to note the increased ard colors-brown, red, and black -is rich The mouthpieces can be washed and thoroly resistance at the higher temperature. (1 megohm and handsome in appearance. sterilized as moisture, acids, or steam equals 1,000,000 ohms.) Bakelite has many valuable qualities leave no effect on Bakelite. Comparison with ordinary and well - which make it especially suitable for me- The general physical properties of Bake- known insulators is the criterion that shows chanical pieces, sometimes made as die - lite moulded material are given below. where Bakelite stands in the electrical castings. It is strong and light- weighing They vary according to the composition world. Note the last column at the right only about one -third as much as die -cast- used. in the above table and then note that: - ings and has a specific gravity of 1.35. The Hard rubber shows 2,000,000 megohms per beautiful finish is Specific Gravity: 1.33 to 1.89. normal permanent; there is no Temperature Resistance: 300° F. to 400° F. centimeter cube at temperature; enamel or other surface coating to wear Dielectric Strength (average): 250 to 425 volts mica, 3,000,000 megohms cm. cube, gutta off, no plating or japanning. It is more- per mil. (Continued on page 851)

www.americanradiohistory.com 802 THE ELECTRICAL EXPERIMENTER \larch, 1917 Patriotism EFORE we go further, we might as did you get yours when you 'created' that Our illustration of a copy of the "E. E." well admit it. When it comes to latest masterpiece." sent to us from Boston proves it amply. B front covers, THE ELECTRICAL Ex- Or else someone calls him on the wire Alas, these good people who thus wrote PERIMENTER is on deck with a whoop. Whoop and informs him that the S.P.C.A. threatens us wrathfully, did not know the patriotic with a big W. As for noise -yes we don't to have him arrested. "S.P.C.A." shouts laws of their fair and enlightened state. deny it -our average cover designs, outnoise the chief in the phone, "what in thunder For, gentle reader, in case you have not the biggest 1917 Model Klaxon. Now, of have I done now to an animal ?" "Animal heard of it before, Massachusetts, a most course, we fully realize that our cover de- my eye" chuckles the other party, "S.P.C.A. learned and civilized state of these United stands for Society for the Pre- States has among others a cute little law vention of Cover Atrocities!!" which forbids all humanity and others from openly ' and so on. selling any object whatsoever on ÉseElectricäl6°6' But we did not start out to which the Stars and Stripes are displayed. xperimenter tell you about all this; rather we Whether the object be a Magazine, or a Experiment w wanted to say that our weirdest Bible, or a box of cheese, matters little. PIMA 431 covers as a rule only draw fav- Don't ever dare to put such objects in a orable comments, presumably window display. The Massachusetts police because they make people think, will make you take it out or else arrest hence are really useful, despite you. Pretty little idea that, to create pa- the loud colors. triotism in one's breast. And all this in Now then our January cover highbrow Mass! was really a very artistic affair. But perhaps you don't get the correct One of the sanest as well as "drift" from our prose. For that reason best executed covers we ever we are moved to poetry which will make had. Being such, it goes with- everything plain as a plane: out saying, that H.G. had not concocted it. Rather, a very MASSACHUSETTS FLAG SONG eminent artist conceived and executed it, namely Mr. John Tramp, tramp march the Cops Pasting Santa Claus Stickers Over the Stars and Stripes Is Not A. Bazant. Yes, a New Fad. Nor a New Christmas Wrinkle in Dear Old Massa- the same Baz- Licking their chops. chusetts. It's the Law. Goods Displaying Our Flag May Not ant whose design won the 2nd All is hunkydory, De Sold in This State. prize of $500 at the recent prize If you hide Old Glory. contest of the Society for Elec- But don't wag, signs are loud and are trying their level trical Development where 800 paintings and best to outshriek all other noisy covers on drawings The Old Flag. had been submitted to the judges. If you do the crowded news stands. But you buy Despite this, strange to say, our January them, don't you? So do thousands of cover called forth more unfavorable com- Woe to you. others every month who had never before ment than any other cover we ever had. Says the cop: heard of the magazine. They are attracted Beginning with the first day after publica- "Now you stop by the bright sometimes screaming colors. tion, sarcastic letters began to pour in, ask- If the flag is here on sale, If at all interested, the net result is a new ing us if we had ever seen the American You must go to jail. reader. As the bulk of our readers are flag painted backwards. Others wanted to If the flag is on your Bible, news stand buyers, it naturally follows that know if the Germans would respect the You'll be pinched for libel we wish to attract the greatest possible Stripes and Stars, being that this was a If the flag is on a postcard amount. Our covers seem to accomplish brand new kind of flag. Still others lam- Or if it's on the go -cart. this successfully, it would seem so, for basted us with the argument that the flag If the flag is here on sale. in three short years THE ELECTRICAL Ex- made for backward neutrality ! .Come with us to jail. PERIMENTER has reached a circulation of Of course all these good people were If the flag is on a postage stamp, 73,000 copies, larger by far than that of any wrong. Moreover they probably were Or if it's on your auto lamp,, other two electrical periodicals combined. "landlubbers." For the flag is painted right. Perhaps it's on your letterhead, So you see that the Editor's main and Just imagine a flagpole on the flag, the printed staple Or on your cigarette vice -E.E. Front Covers -is pardon- whole set in the bow of the ship. Will it not flag is here for sale, able. He lays awake nights If the waiting for in- then appear exactly as Mr. Bazant painted You'll be put to jail. spirations (or shall we say conspirations) it. You see when you look at the starboard If the flag is in your straw -hat, and given six good ideas he will pick out side of a moving ship, any flying flag of the most startling one. Being that all the Or if it's on your baseball bat, the Stars and Stripes appears backwards. on "good" ones strike him between 12 A.M. The next surprise If baby's sand tin -pail, came from Boston, Rightaway you and 4 A.M. his friends, when out of ear- Mass. As a matter of fact, there were go to jail. shot (as well as other shot) call the ideas quite a good many from Massachusetts. If it's pressed into your soap, nightmares! When a particularly "hot" one Irate readers wanted to know what we Or on the label of your "dope" makes its first appearance by setting fire to meant by pasting Santa Claus and other If it's on ten dollar bills the news stands, intimate friends are wont paper stickers over the United States flag, Or on a box of bitter pills to call around at the Chief's office with such thus hiding it. Since when are we ashamed If the flag is here on sale, comments as: "Listen H.G. w,hat dope do of our Flag, and if we did print it, why Pay the kale or go to jail. you take now before going to bed ?" or "I did we cover it up? The argument was That's the law in dear old Mass thought opium smoking was taboo; where perfectly logical and was backed by facts. Come along, you're pinched, my lass. UNIQUE ELECTRIC TOY ENGINE. constituting the pistons which are joined pie and it depends upon the electromag- A unique electric toy engine of excep- to the flywheel shaft by means of connect- netic suction of the coils upon the iron tional power has been developed recently ing rods. by Mr. Thomas H. Phillips and is shown The four coils which make up the two herewith. 9 main solenoids are connected in such a The general construction of this minia- manner that each one of them act upon ture prime- mover, so dear to every boy's the piston at certain definite periods. The heart, is quite different from any of those two forward coils are connected in series with which we are already familiar, i.e., and their terminals linked to the battery a pure solenoid action is utilized in this binding posts of the engine. The remain- machine similar to an actual steam engine, ing four wires terminating from each coil whereas the others employ ordinary solid are connected to a set of four fixt seg- core magnets acting inefficiently upon a flat ments, which are placed on the left hand iron armature. Another feature of this shaft support. These are made from brass engine is that it has no dead center and will and placed in circular order. The shaft start every time, irrespective of the posi- carries a brush which plays over this fix[ tion of the connecting rods and crank shaft. commutator, so as to connect the neces- A New Toy Electric Engine with Double Wound It consists of two solenoids, each of sary coils progressively to produce rotary Coils, That Is Extremely Powerful. which contain two coils, wound side by motion of the shaft. The connection to this pistons. This is of course accomplisht by side, but separated from each other by an brush is made thru the frame of the en- the manner in which the coils are con- insulating washer. The cylinder is made gine. nected to the fixt commutator. The engine from brass tubing and fitted with iron rods The operation of the engine is very sim- runs very fast on a single dry cell.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 803

A NEW OZONE MACHINE OF FOOL-PROOF FIRE ALARM BOX. sels, 2 of which are high -power stations, MANY USES. The accompanying view is that of a fire 10 of medium power, and the rest of lower The ozone machine shown herewith con- alarm attachment invented by James P. Mc- power, for communication with ships. In a new medium -power station has sists of a main frame of preferably alum- Laughlin, which it is proposed to place on addition, inum, constructed with annular end pieces the Fire Alarm signal boxes in Philadel- been completed and will soon be put in phia. service at Point Isabel, Tex. This station The scheme as shown is a direct acting, will be of great service to the merchant keyless door with alarm attachment. The marine in that section, as well as to the operating lever, shown on the outside of Government in facilitating communication floor, has an extension arm on the shaft with vessels in Mexican waters. Within extending thru the door. When the the next year it is expected that at least outside lever is pulled down, the extension two new high -power stations will he com- arm engages the hook which operates the pleted, namely, at San Diego and at Pearl box mechanism and when pulled to the Harbor. \Vork is progressing satisfactor- ily on the Cavite high -power station, also full downward position, enables the ap- on medium high -power stations at Puget paratus to deliver four rounds of the sta- code number. Sound and at Cordova, Alaska. Estimates tion have been for high - The lever has a submitted another shaft on the pulling power station on the island Porto Rico, rack also attached to it, which, when of bell- primarily for use in naval operations. operated, causes the striking alarm Marked improvement has been made in OZONIZED attachment to operate thru a pinion and the radio equipment of ships and of the At escapement. The alarm is given by the more important shore stations, enabling Ozone Machine for Alternating or Direct Current. pulling down of the lever and also on the wireless communication to be maintained Discharge Produces its posi- A High Tension Transformer return of the lever to original over greater distances and securing an un- the Ozone, which Is Blown Out Into the Room by tion, propelled by a strong spiral spring a Motor-driven Fan. failing means of cross -continent communi- attached to the rack. cation at all times. Distant control sta- which are provided with slots extending This scheme is mounted on the original tions have also been established at the inwardly from the periphery of the rings door of the boxes, and while it does not principal stations. toward their centers. These annular end prevent the sending in of malicious false pieces or rings are held together by longi- alarms, it, when operated, produces suf- AN ELECTRIC HEATER FOR AUTO tudinal bars. A series of comb -like elec- ficient noise to at least discourage such ENGINES AND CARBURETORS. trodes are arranged to fit in the slots. The practise and may attract the attention of The purpose of the new engine and car- electrodes consist of a strip of con- buretor electric heater here shown, is to ducting material, and have a series keep the engine and carburetor warm dur- of laterally extending teeth. When ing cold nights. Every private garage will these electrodes are placed in the find it useful. It is attached to any electric slots the ends of the teeth will light socket and placed under the hood - lie in the same distance from on the engine and as close to the the center of the rings. The carburetor and manifold as possible. electrodes are held in place by If the weather is severe, blankets means of rings which fit over the should be placed around the hood to annular end pieces. The di- electric hold in the heat. Generating just is a thin glass tube. Within the tube, enough heat to keep the engine, car- at a short distance from each end, buretor and radiator slightly warm, is an insulating washer. On each it eliminates starting trouble with its end of the tube is a cap made of in- resultant strain on the starting bat- sulating material. Between the wash- teries and the wrapping of hot cloths ers the tube is filled with a finely - around the manifold and carburetor powdered conducting material. A to cause the gasoline to vaporize metal conducting rod extends thru properly. Moreover, it saves the the tube from end to end, with the wear and tear on the engine caused ends of the rod threaded to receive by cold oil. nuts which hold the caps in place. The body of the heater contains The rod forms one terminal, to which a rugged heating element which con- one pole of a high tension trans- Novel Fire Alarm Attachment That Rings Gong Shown when sumes one -tenth of a kilowatt -less former is attached, the other pole Box 1 s Operated. Intended to Discourage Sending in of Mali- than one cent an hour in cost. This being connected with the frame eious False Alarms. element is enclosed in a black metal which holds the electrodes. The dielectric some one standing near it, making pos- shell -shaped like and about the size of an prevents sparking between the teeth and sible the apprehension of the maliciously ordinary dry cell -which is perforated to the electrodes and the conducting material, inclined person operating the box. allow for the circulation of heated air from but it permits a static discharge thru the glass in the form of a glow or fine SECRETARY DANIELS' REPORT brush. The ozone produced is blown ON NAVAL RADIO SERVICE. out into the room only by a motor -driven The name of this service will be changed fan of special construction. to naval communication service in the near future, it having taken over the handling of all telegraph, telephone, and cable com- AIRSHIPS USE WIRELESS SUC- munications and generally all dispatch work of the Naval Service outside the CESSFULLY, SAYS MARCONI. fleet, in addition to the work of the radio Upon his return to London from Italy, stations, says Secretary of the Navy Daniels Dr. Gu ?lielmo Marconi, in an interview in his annual report. The Government and with British journalists, gave the following commercial needs have been efficiently information: "New developments will not served. As an illustration of the growth only make wireless communication in this of the Radio Service in the past few years war more efficient than ever before, but it may be noted that during the period from will make it more difficult for the enemy to December 13, 1912, to December 31, 1913, intercept messages. These improvements there were handled a total of 12,854 com- will apply to instruments in aeroplanes and mercial messages, while during the past airships. Hitherto aeroplanes have been at fiscal year 97,084 commercial messages were a disadvantage with airships in wireless handled. The number of official messages work, for altho they were able to transmit had correspondingly increased, the number messages, they have not been able to re- for the fiscal year being 628,997. Extremely Useful Device for All Motor Car ceive them. This was because the received The' Tuckerton and Sayville Stations Owners -an Electric Heater for the Engine and signal was too faint to be distinguished, have been successfully operated under Carburetor. being drowned by the noise of the aeroplane naval control during the year with great engine. Now we have been able to strength- profit to the owners. within. The outfit weighs less than one en the received signal sufficiently to enable There are 51 radio stations of the serv- pound and is equipt with ten feet of cord messages to be taken." ice in operation ashore and on light ves- and an attachment plug.

www.americanradiohistory.com 804 THE ELECTRICAL EXPERIMENTER March, 1917 Experimental Physics By JOHN J. FURIA, A.B., M.A. Instructor In Physics and Science Master, Riverdale Country, School LESSON TWO. pose this experiment were performed in a out to get into equilibrium with the rest of Explosions and Explosives (Concluded). closed vessel. Obviously the gas formed the air around it, was the explosion. Note IN the last lesson we noted that for would exert greater and greater force as that a large amount of gas in a small vol- any gas whose quantity is always the more and more gas was formed as this would urne was the beginning of the cause of the same, the pressure it exerts multiplied be concentrating the gas in the given vol- explosion: by the volume it occupies is always the ume. The ordinary fire extinguisher is a Experiment 6. Blow up a paper bag. same. (Boyle's Law.) Also, whenever piece of apparatus making use of our funda- Strike a friend on the back with it and no- in a given volume we have a greater amount mental principle of explosions. (Ste fig- tice the explosion. After blowing up the of gas than usual, the gas exerts a large ure 7.) (c) is a metal cylinder nearly full bag the air in it is not comprest. It has of water ; (b) is a bottle fastened to the the same pressure as the surrounding air, sides of the cylinder and containing sul- but on striking something with the bag, furic acid. Bicarbonat of soda is solved in the water in (c) ; (a) is a stopper which fits loosely in the bottle (b). When the extinguisher is inverted, the sulfuric acid gradually mixes with the solution and forms a gas. The tremen- dous pressure of the gas forces the solu- tion out thru the hose (d) and some of the gas itself comes out also. Both the water and the gas extinguish the fire. Since

v" ,,.., IN THE APRIL "E.E." A new electrical scheme for de- A Safe and Sane Way in Which to Ignite Fire - tecting submarines or sunken wrecks crackers-a Small Spark Coil, Battery and Push A Typical Example of Gas -energy 'Apparatus- -an idea that may be of inestimable Button Does the Trick. the Fire Extinguisher, in Which Sulfuric Acid value to Uncle Sam. Mixing with Bicarbonat of Soda Solution Gener- there is a tendency to make the air oc- ates Gas. This Forces the Solution Out of the The "Strong" Hiyh Frequency Ap- cupy a smaller volume; its pressure is in- Hose "D.' paratus and its application to elcctro- creased, and the bag bursts with an ex- therapeutics, by Dr. Frederick Finch force and the greater the compression the plosion. (The author learned to perform Strong. this experiment in school when the teacher greater the force. The Aeroplane of To-day--how Let us define an explosion making use was not looking.) electricity starts the engine, lights E.rpt'riment 7. In order to understand of the results of Lesson One. We have the cabin, provides telephone service an explosion whenever we have a gas un- chemical explosions, the reader should and automatically stabili:es the ma- weigh some iron filings, heat them and der such great pressure that it bursts its chine while in flight. container. It is the tendency of forces weigh again. He will find, if he has suf- to Baron Münchhausen's New Scien- ficiently sensitive balances, that the iron set's equilibrium that causes the explosion. tific Adventures, by Hugo Gernsback. Hence the first prerequisite gains weight. The explanation is that the to an explo- Electricity in its application to mo- iron filings combined from sion is a large amount of gas occupying a tor- boats. with something small volume. This large amount gas the air (a gas named oxygen) and thus of The R -ray -a new discovery in increased in weight. In like manner we in a small volume exerts a tremendous medical electricity, by H. Rosenthal. force and when the force is can heat certain other substances and have great enough Gases and the Atmosphere -Third do reverse of this, i.e., give up to burst the container we get an explosion. paper the new them the of series-"Experi- some the gases on heating. That is the In some cases we may cause a large amount mental Physics" by Johns J. Furia- of of gas to occupy a small volume by com- I.B M.A., principle of explosives. An explosive is a F.K.S. substance which by heating or percussion pressing the gas. This is the physical Construction of a small direct cur- means of doing so. The chemical means, rent suitable can be made to give up gas which is com- generator- for lighting bined it. This suddenly formed which we shall discuss later, is generally lamps and running numerous other with gas to transform a solid or liquid into a gas, apparatus, by George Sturley. in a small volume gives an explosion. which process because of the lightness of Receiving the Marconi High -Pow- Gunpowder, dynamite, nitro -glycerin, etc., gases, causes a large volume of gas to er Stations with the Oscillating Au- all contain gases which they give up on appear in the small volume which the solid dios, by Samuel Curtis, U.S.N. exploding. or liquid occupied. The How and Why of Radio Ap- Experiment 8. Strike several blows with Experiment 4. Dissolve paratus a hammer and then feel the hammer. The a little bicar- -Part 4-The Spark Gap. feels The force the ham- bonat of soda in water. Drop a little The Measurement of Inductance. hammer hot. of concentrated sulfuric acid in this solu- Part 2 of a series on this all- impor- mer hitting creates heat. Hence if we tant and timely subject, by H. Win- have a substance that will give up gas on field Secor and Samuel Cohen. slight heating, striking it a blow will set The Coast -to -Coast Amateur Ra- it off and cause the explosion. It is there- dio Relay (Washington's Birthday fore wrong to say that we light a fire- Relay), by W. H. Kirwan, 91E. cracker, since the light does not cause the Electro- plating Mirrors by a New firecracker tó explode. It is the heat that Vacuum Process...... ,..,,,.,.,...,..,...... , ...... , .. .:11111111111 ...... ,...... 11111111111111111111111111111111111111111111111111111111111111 the bottle containing the sulfuric acid is fastened upright, the acid cannot mix with the solution unless the apparatus is in- verted so as to release the stopper. Experiment 5. If you own an automo- bile or a Ford and run it over some glass, nails, etc., you will notice that an explo- The Modern Rifle Bullet, Is Based on Explosive sion occurs as the tire is punctured. If Action. The Cap Ignites the Powder -"b," the Gas of Which Being Confined, Forces the Bullet you do not own an automobile inflate a toy "a" Out of the Gun Barrel. balloon and puncture it. An explosion will occur. The gas in the automobile does it. Whether we produce the heat by an To Demonstrate How a Gas Explodes Violently, tire was under tremendous pressure and electric spark, by percussion, or by lighting Fill a Milk Bottle with an Inflammable Gas. Pass an Electric Spark Between the Cork Wires, When the tire was strong enough to withstand is of little importance. the Cork Will Be Blown Out of the Bottle. the force, but when the tire was slightly Experiment 9. Procure a glass cylinder ript by the glass, it was no longer able to or bottle made of thick strong glass. Fit a tion carefully by the aid of a fountain do so and the explosion occurred. The air cork stopper to it. (See figure 8.) If a pen filler. A gas is formed rapidly. Sup- inside the tire (or tov balloon) rushing (Continued on page 852)

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 805 RADIO LEAGUE HONORARY MEMBERS CAPT. W.H.G.BULLARD. U.S.N. NIKOLA TESLA. `'AMERICA PROF. REGINALD FESSENDEN. DR. LEE DE FOREST. II. Gernsback, bl anager 11%11. Kirro n,:M,n Lr of Radio Rrlavs The Washington's Birthday Relay, February 24, 1917 By W. H. KIRWAN, (9XE) Master Radio Relays, Radio League of America N the night of February twenty -fourth, every wireless amateur, as well as every member of the Radio League of America, will have the chance of his life to show flic world how efficient he is and how much he knows about wireless. Mr. W. H. Kirwan, O of wireless fame, has arranged for a double -barreled transcontinental .¡mateur Wireless Relay, that will set the country a -talk- iug! On this memorable evening, a New York amateur will obtain a certain message front the mayor of the City of New York and this message (the contents of which will be kept secret until 9 P.M., February twenty- fourth) will be relayed over special amateur stations across the country, to be delivered to the mayors of the ll'est Coast cities. Simultaneously, another message will be handed to a California amateur by the mayor of Los Angeles, and this message will wing itself eastward, front one amateur station to the next, until it is finally delivered to the mayor of New York. Only special amateur stations listed will do the actual sending. All other amateurs are strictly requested NOT TO SEND, but to listen in only: As soon as you receive the M.S.G. (message) rush it to the mayor of your city and get a receipt for it. Valuable prizes will be given for good and speedy work. February twenty -fourth promises to be an exciting evening for all Radio amateurs. We hope you will be on deck and let your motto be: "Watchful Waiting!" EVERAL criticisms recently made 9,11111111111111111111.111111111111 Iou Mr. George C. Cannon of New Rochelle, about the different relays arranged N.Y., will start the M.S.G. from station Our many radio amateur friends 2ZK, on a for by the writer, lead one to be- undoubtedly wave length of 350 meters as lieve Radio Amateurs of this will be glad to learn soon after N.A.A. routine report that the that Mr. W. II. Kirwan has on the a final promised night of Saturday, February 24, 19I7, country are prepared for test to write one as article each month for a becomes possible. Catch his "sigs" of their skill in relay work. We have been period of twelve months, if you trying in our small way to educate the for THE can. Mr. Cannon has agreed to act as east- ELECTRICAL EXPERIMENTER. ern manager this relay workers up to the point where successful W. H. Kirwan, Master of and Mr. Robert work could be done; while we admit many of Relays T. St. James, IIZ, Great Barrington, Mass., for the RADIO LEAGUE OF and Mr. stations are relaying now satisfactorily, not AMERICA and known C. H. Stewart, 3ZS, St. Davids, until recently have M.S.G.s (messages) to the ama- Pa., will act as his right and left flanks to been relayed successfully from coast to relay the M.S.G. one -half hour later south coast. We have outlined a plan which will and north, so that all of you on the East- really be a true -blue test or race between ern coast may get it, but these stations amateurs and special stations, and while will not send it until one -half hour later we appreciate the good work the special than the time Mr. Cannon starts it, and no stations have been doing-my hat goes off station other than these is asked to re- to the amateurs who are the real men be- send it until next day except 8NH. Write hind the guns in all relays. down the M.S.G. you receive -station send- We propose to try and send a M.S.G. ing-time to the minute and deliver a copy from the mayor of New York City and de- of it to the mayor of your town and obtain liver it to the mayors of the West Coast, a receipt for it. This is important as you using special stations going westward. We will see later. The other sending stations propose to try and obtain a M.S.G. from as listed will be worked in the order of the mayor of Los Angeles and deliver it to the list and the preceding station will call the mayor of New York, using amateur sta- the next station on the list and give him tions only going eastward from the West M.S.G. and Q.S.L. This station will call Coast. next station and so on down the line until Every amateur in the country is asked to station 8Y0, Columbus, Ohio, receives the try his skill at receiving these messages and M.S.G. He will then call 9ZS, Spring- for heaven's sake please do not send -but field, Ill., Illinois Watch Co. If 8Y0 can- listen, and you will have a bigger job and not get him QSA -let them send M.S.G. attain more valuable results and prizes than on Q.S.T. and 9ZN, Mathews of Chicago, for a few minutes' sending. You all have W.L. 425 meters, will take M.S.G. and a whole year for sending and we ask you give it to 9XN, Grand Forks, N.D., and to please try and quiet everyone in your 9XV, Washington University, St. Louis. state so that you may all try for a prize. Mo. 9XN will give it to 9ZF, Denver, and Any station not listed and sending in de- get Q.S.L. 9XV will wait teur until 9XX has fiance of our most earnest request will be world as 9XE, was born in Bal- sent and if no Q.S.L. is received by 9XN noted and his "call" publisht, as well as timore, Md., February 5, 1881. Grad- 9XV will call SZC, Corlett, Dallas, Texas, uated in Steam: having his intentional interference brought and Electrical Engi- who will give' it to 9ZF, Denver, a station to the attention of the Radio Inspector in neering in 1897, Brooklyn Poly - owned by Mr. Doig Mr. technic and aided by his district. Now boys, we have spent lots institute. Six years in Smith of the Y.M.C.A. Radio Club of of time on these preparations and have the U.S.N. fitted him for life's more Denver. This station, will serious work. 9ZF, be flanked been busy working while you were peace- Six years' study of by 9XN on the north and 5ZC law prepared him: the he on the fully sleeping, so please take out your fuse for bar, but south, who will assist if necessary, if took up Engineering instead. QRN plugs on February twenty- fourth at 9 P.M., (lias is bad in trying to get M.S.G. thru to Eastern time and keep them out. A rep- Assisting Erecting Engineer at the 6EA, Seefred Bros., Los Angeles, Panama Canal for the Emergency as has resentative of every wireless organization been done several times in some recent Dam machines, and has been in in this country is working on this relay and ev- tests. 9ZF will have as a relay station ery civilized country on the globe if we have old men and boys-amateurs and necessary 6DM, R. Higgy in Phoenix, that has a seaport. He has been experts -and the Government authorities Ariz., and also 6SH, our old friend Mac - a student of iVireless Laws are watching closely all these tests -so since Quarrie, at Stockton, Cal. don't get in bad by interfering, before you Marconi first flashed lais signal across the Atlantic, Our old standby, 7YS, St. Martin's Col- get a flying start in the game. and he has lege, Lacey; Wash., has promised to be on grown up with the new art. He is _- the job if we start it before his bedtime, STARTING M. S. G. (MESSAGE). _ the author of the National Relays and the so it will be up to 7YS to give it to Van- All of you wisht for something hard on Q. R. M. League of the U.S. He is at present Superintendent of couver, B.C., and also to Seattle. This re- the other relays and many complained be- Construction inforcing or flanking of sending stations cause they knew the M.S.G. ahead of for the Otis Elevator time Co., in the States of Iowa and Illinois. was necessary owing to the northern route -so your wish is fulfilled now, you have thru Lewiston, Mont., and La Grande, Ore., the job of your life on your hands. llll (Continued on page 848)

www.americanradiohistory.com 8o6 THE ELECTRICAL EXPERIMENTER March, 1917

Controlling Toys by Radio ONE of the most spectacular and close the main battery circuit. A definite ed on a suitable shaft which is substan- interesting electric toy outfits ever time interval ensues before the piston falls, tially fastened to the board. The cog is conceived was recently built by thus permitting the operator to turn the caused to rotate by means of a ratchet arm, Mr. Thomas H. Phillips, of rotary switch (by radio waves) to the de, C, which is held on a vertical rod as the Brooklyn, N.I. This novel and sired position before closing the main cur- reader will perceive. The lower end of ingenious display consists of a large num- rent circuit. The time interval is controlled the rod is fitted with an iron armature, D, ber of toys mounted on a platform and by means of a check valve placed on top which is acted upon by two electro -mag- controlled by wireless waves produced by of the cylinder, which may be seen clearly nets, E, E. A guide -rod is attached to the operating a spark gap excited by a spark in the photograph. A stop lever for the end of each pole -piece, which passes thru a coil. The radio controlled toyland is il- cogwheel is also provided to prevent the hole in each end of the armature. This is lustrated at Fig. 1. The transmitting ap- wheel from making more than a single used for maintaining the rod in a straight paratus is shown at the left, just in front connection at a time. position. Both electro- magnets are held to- of the child, who is manipulating the key The complete wiring diagram of the ap- gether by a suitable yoke and a hole is The receiving and controlling apparatus, paratus as used by Mr. Phillips in his made in the center for the control rod to which are the most important features of Christmas outfit is given at Fie. 3. pass thru. The stop lever, F, is made from the equipment. are arranged on the floor For the benefit of those who are inter- brass and shaped as indicated. It is pivoted underneath the ta- on the end of a brass pillar. This is ac- ble. Fig. 2 shows complisht by a little experimenting. Be- the complete de- fore going on further with the construc- vice ; the receiving tion, it is advisable that the instrument so and controlling Fig. I. Inventor's Daughter far finished should be tested to see that Operating a Spark Coil, the the cogwheel is when mechanism. Waves from which Actuate properly operated, The controlling the Electric Toys Shown. the electro- magnets -re energized by means device is not of the of a battery. The control rod should be step by step type, held in place by means of an additional 1 but of the selective standard H. type ; that is to say, We now come to the most essential part any toy (or other of the instrument and that is the time -con- device) can be op- trol attachment, which makes the complete erated without in- instrument selective. This is indicated by terfering with the I and consists of a steel cylinder about 2 intermediate circuits inches long by half an inch in diameter. A of other toys. Thus, three -eighths inch if it is connected to hole is boiled in ten different toys, this, into which a say in consecutive Below: -Fig. 2. T h piston, J, is set, order such as (1) Clever "Selective" Re- which is about half lay Apparatus Enabling long. A an electric train, Oneto Control Any One an inch (2) engine, (3) of Several Devices. great deal of care lamps, (4) merry - must be exercised to go- round, (5) spot see that the. piston lamp, and (6) elec- fits very snugly in tric fountain, it will not be necessary to con- the cylinder and at nect first the lamps if it is intended to op- the same time loose erate the merry -go -round or the spot lamp. enough to permit it In the step by step control system, it is of falling very slowly course necessary for the operator to connect when it is entirely the lamps before he can connect the mer- inside the cylinder. ry-go- round. Altho the control switch is The air between the built along the lines of a step -by -step relay, piston and the upper yet by the addition of a time switch, the wall of the cylinder inventor makes it a selective device. acts as a spring on This switch is seen in the center fore- the piston, so that ground of Fig. 2. The two electro- magnets when it is in, the air are connected to a polarized relay seen at gently forces it back. the lower right -hand corner, which is con- It is advisable to in- trolled by a coherer shown in the left -hand sert an air valve on corner. An armature is placed across the top of the cylinder pole -pieces of the electro- magnets and is ested in this work, the following details are so as to control and adjust the air within the fitted with an extending rod. This rod is given so that one may readily duplicate it. cylinder. This will aid the operator to con- set free and permitted to move vertically, Furthermore the radio dabbler can use trol the speed of the descent and ascent of so as to act upon a ratchet wheel by means this type of relay to great advantage in con- the piston. The complete relay is mounted of an arm attached to the rod as shown. trolling moving vehicles such as boats, sub- on top of the board in such a position that A switch lever which plays over a number marines, torpedoes, etc., by means of ra- the control arm is just in the center of the of contact studs is attached to the ratchet dio waves. face of the piston, as shown both in the di- lever. The time -control element is placed Referring back to Fig. 3, the construc- agram and Fig. 2. The relay control switch directly over the end of the movable rod tional details of the special relay are shown. consists of a heavy brass plate, K and a and consists of nothing more than a small The complete instruments are mounted on flexible phosphor bronze spring, Ki; these brass cylinder fitted with a piston. Just a base -board 8 x 5 inches. The cogwheel are placed together, but separated by means below the piston are two horizontal contact A consists of a flat brass disk containing of a hard rubber washer, L. Both are levers, which constitute the main circuit ten notches which are made by carefully mounted on an insulating plate, M. When switch. These are normally open when the marking the perifery with a marking tool the piston J is up in the cylinder, the con- piston is well within the cylinder, being and filing down the teeth. A switch arm, B, tacts should be open, but as soon as the kept there when the electro- magnets are en- is soldered to the wheel, the length of piston falls, due to its own weight and the ergized; but as soon as the lever is low- which will depend upon the distance of action of the air within the cylinder, the ered the piston is released, thus causing the the contact studs from the center where the spring Ki is caused to interlock with its two switch levers to come together and 'cogwheel is stationed. The wheel is mount- mate, K, thus completing the electrical cir-

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 807 cuit as becomes evident from the wiring accessible than the poles and wires usually concrete. The contract for building the diagram. thought necessary for wireless telegraphy. dormitory for the eight operators, the yeo- An additional extension, N, is made on And there's bound to be a sudden boom in man and the cook, and for the noise -proof the armature, which is equipt with a con- amateur wireless when Young America instrument house, has been let to the tact on its end as indicated. This acts up- hears that he has a latent wireless plant Charleston Engineering and Contracting on a stationary contact screw, O. These right in his own bed. Co., all work to be finished within four two contacts are used for completing the (Midshipman Dow probably is unaware mouths after begun. circuit of the coher- The Pittsburgh - er tapper, used for "o v Des Moines Steel decohering the fil- Co., of Pittsburgh, ings. This completes DI Pa., will construct the construction of the two tubular the selective relay steel masts and the and its success of tower of latticed operation will de- steel work, includ- pend upon the man- ing the driving of ner in which the va- piles and the an- rious parts are made chorage work neces- and assembled. sary. One hundred The diagram of and fifty days are the complete con- allowed for the nections is given in completion of this. Fig. 3, and it shows When all the actual a number of devices construction has which have actually been completed the been controlled by plant will be turned this instrument, but over to the Navy the constructor may Department. use the idea to con- The contract for trol other toys or the building calls instruments which for the erection of he may desire. a structure twenty- The transmitting eight feet by thirty apparatus may con- as a dormitory, and sist of a one -inch a single room nine- spark coil, large ball teen feet by twenty-se spark gap, key and four to house the batteries. The aerial instruments. T h e and ground can be latter room will be made of a heavy thoroughly insulat- brass wire suspend- Tróin tSo%noiá ed from the ground ed from the spark ei,g/ne and from the sur- gap terminals. A rounding at m o s- transmitting outfit phere by several lay- suitable for this Spot /omp ers of non- conduct- kind of work may Ned fou,jlo%i'- Q ing material built be seen at the left into the walls and of Fig. 1. How the Various Apparatus, Such as Table Fountain, Lamps, Electric Engine, etc.. Are Connected Up doors. The four The operation of to the Novel Radio Control Relay Here Described. The Relay Operates on the Selective Principle. walls and ceiling the complete equip- will be lined inside ment is very simple ; it is only necessary to ac- that the brass bed aerial stunt was fully with felt, instead of paper or other usual quaint one's self with the connections. Thus, described some eight years ago in Modern wall coverings, in order to make this in- if the operator desires to operate the sole- Electrics!!- Editor. ) sulation all the most perfect. Even the noid engine (see Fig. 3) he must press the doors will be packed with non -conducting key twice, which will turn the switch lever KEEP WIRELESS FREE URGES material and will resemble those of ice B to the second stud. Suppose it is desired PROF. KENNELLY. boxes. There will be no ventilation what- to run the electric fountain; he then presses Prof. A. E. Kennelly, of Harvard Uni- soever by means of windows, and in order the key six times; this will turn the arm versity, told the House Committee on Mer- to supply the occupants of the instrument B to the proper contact and connects the chant Marine at a recent hearing that the room with fresh air, an electrically driven fountain. A few trials as to the operation Alexander bill for government regulation fan will be used, forcing fresh air into of the complete equipment will possibly be of radio stations is nothing less than an at- the room from out of doors thru a series necessary at first before one can master it. tempt to control the freedom of the air. of baffles. A vent will be provided to per- The operation is very simple and it will "The bill is just such a measure as Gen. mit the escape of stale air. certainly repay the amateur for making Von Bissing might promulgate for Belgium, such an equipment; it will give great fun but is absolutely inconsistent with free in- LOS ANGELES Y.M.C.A. WIRELESS and amusement, and at the same time prove stitutions," he said. GRADUATES. immensely instructive. "Designed as this bill is to protect the Kenneth G. Clark, a resident of Los An- Navy from interference and disturbance in geles and a graduate of the Y.M.C.A. wire- WIRELESS BEDS. its communications, it would have the op- less school in that city, has just received An Annapolis midshipman named Dow is posite effect," he declared. his appointment from the Mexican govern- credited in local papers with an ingenious Prof. Kennelly urged absolute freedom ment as "Ingeniero instalador de las es- and useful discovery. He has found that in the development of radio- communication taciones inalambricas del Distrit," which, in ordinary bed springs make good wireless thru every agency, rather than to place the English, means radio engineer in charge of receivers. Having connected with wires the whole science of wireless communication construction. Mr. Clark will have super- springs of his own bed and the beds of his under government supervision. vision over the erection of a number of two roommates, and attached an ordinary Prof. M. I. Pupin, of Columbia Universi- wireless stations in Mexico, beginning at wireless receiver, Dow is picking up mes- ty, also opposed the bill. "The wireless art Tia Juana within a few days. sages without any difficulty, especially those is a promising and healthful young baby, Another graduate of the Los Angeles sent to and from Arlington station. It isn't which the proposed bill would take away Y.M.C.A. wireless school, H. D. Hayes, even necessary, he says, to open the win- from its lawful parents and place in a gov- organizer of the work and for four years dows or to remove the bedding. The beds ernment institution," he said. principal, has been reappointed assistant stand just as usual, serving their original United States radio inspector for the Paci- purpose, and the occupants can amuse them- POWERFUL NAVAL RADIO fic Coast for another three months, having selves as they lie abed by gathering in any STATION AT CHARLESTON, S.C. received his first appointment to the gov- messages that happen to be flitting about. Contracts have been awarded for all the ernment service last September. He is now This looks like a more useful innovation construction work on the naval radio re- stationed at San Francisco. than that of the Harvard student who at- ceiving station, which is to be erected at tained fame by rigging up an electrical sys- Charleston, S.C. It is to cost about $18.700 Courts have recently sustained the pat- tem to pull his window shades down whet' and the work to be completed within 150 ents on Mazda lamps owned by the General the morning light bothered him. Bed- days. A force from the navy yard is to Electric Company, and no further impor- springs are considerably cheaper and more prepare all foundations. which are to be of tations will be permitted.

www.americanradiohistory.com 8o8 THE ELECTRICAL EXPERIMENTER March, 1917 DeForest vs. The Electrical Experimenter A Recent Court Case Wherein the Experimenter Publishing Co. Defeated the DeForest Radio Telephone & Telegraph Co. By H. GERNSBACK ON September 20, 1916, in the Fed- perimenter Publishing Co., charging the the learned Doctor swears to it in his af- eral District Court of New York, latter with contributory infringement and fidavit that the Lenzite Detector infringes before Judge Julius M. Mayer, the asking for extensive damages. on his patents. We are strongly tempted to Marconi Wireless Telegraph Co. Qualifying as an expert Dr. Lee de For- charge the Doctor with bad faith, but on of America won their suit against est in his sworn affidavit accompanying the second thought, we prefer thinking that the DeForest Radio Telephone & Tele- bill of complaint, made the following sur- when he swore to that memorable affida- graph Co. Judge Mayer ruled that the prising statements: vit, he felt in a humorous mood, reasoning Audion was an infringement on the Flem- "Again in November, 1916, my attention no doubt that "A little joker here and then ing patent and the Marconi Company ob- was called to the December issue of said is cherished by the best of men." tained a perpetual injunction against the publication, THE ELECTRICAL EXPERIMENT- Why he just had to pick out the Lenzite DeForest Co. At the present time the De- ER, published by the defendant, and I found detector, will probably remain an unsolved Forest Co. can no longer make and sell the on page 602 an advertisement of the 'Tig- mystery for all time. Why he did not car- regulation Audions. erman Detecto-Amplifier' by the National ry the joke further by claiming that the Described in a few words, the Fleming Electric Manufacturing Company together "Crystaloi," the Tel -Radion, the Mesco Uni- patent covers: "A hot filament and a cold with a cut showing a structure of detector versal Detector Stand, and the Micropho plate, both enclosed within an evacuated which appears to be identical with the ones Detector infringed on his patents we can't vessel." The de Forest Audion, as is well against which injunctions were issued in see for the life of us. This is surprising, known, consists of the above elements, as the suits of the plaintiffs against Myers, for advertisements of these Detectors were well as a third additional member, "the and the Audiotron Sales Company, et al., all publisht in that fateful December, 1916, grid," interposed between the cold plate and in San Francisc6, and Alexander, and the issue. the hot filament. The simple addition of Marconi Company in New York, and iden- Now cornes the comic opera part of the this grid -while admittedly giving better tical with the character of advertisements suit. results than a valve without a grid -did not enjoined in the case against the Marconi As stated before, the papers in question change the basic principle of the Fleming Publishing Company in New York. were served upon the writer on December valve, and for that reason the Court ruled "I also noticed that on page 608 an ad- 4, 1916. On the face of the summons the that the Audion infringed on the Fleming vertisement appears showing a detector Experimenter Publishing Company was to patent. which is an infringement of the plaintiffs' answer on December twenty- fourth. But On the other hand, the Court understood patents, and in this advertisement the struc- by an amazing oversight, Counsel for de- the function of the grid perfectly with the ture is called 'The Moorhead Tube' and of- Forest neglected to fill in several important net result that the Marconi Co. in its turn fered for sale by the Pacific Laboratories dates in an "order to show cause" attached was enjoined by the DeForest Co. by a per- Sales Department of San Francisco, Calif. to the bill of complaint. The net result petual injunction from making or selling "I also found on page 594 of this issue was that on December eighth the DeFor- a valve containing a grid between the fila- an advertisement of the 'Lenzite Crystal est Company obtained an injunction by de- ment and a cold plate. Corporation' offering for sale a detector fault against the Experimenter Publishing Now, then, before these injunctions had which is an infringement of plaintiff's pat- Co., enjoining the latter from publishing gone into effect, the DeForest Co., thru ents, which is called the 'Lenzite Wireless advertisements such as the ones of the Len- its attorney, Mr. Darby, in July, 1916. Detector.' zite people, on their crystal detector, as threatened to bring immediate suit against I also note on page 607 of this issue an well as advertisements such as the ones of the Experimenter Publishing Co. if it did advertisement of the Audiotron Sales Com- the Audiotron Sales Co., the National Elec- not at once desist from publishing certain pany of San Francisco, Calif., wherein an tric Co., the Pacific Sales Laboratories, etc., advertisements, such as the ones displayed illustration is shown of the 'Amplitron,' all on two member tubes. in the July issue of THE ELECTRICAL Ex- the new 'Vacuum Detector- Amplifier-Oscil- A few days afterwards the DeForest peo- PFkIMENTER. The advertisements com- lator,' which illustration shows a detector ple having procured a copy of the Janu- plained of were the following: The Thermo device identical with the structure which ary issue in which these very advertise- Tron Co. of Los Angeles, Calif.; The Pa- the said Audiotron Sales Company was en- ments were publisht again, caused a new cific Research Laboratories, of San Fran- joined from using, as above stated." order to be served upon the Experimenter cisco, Calif.; The Jensen Electric Co., of Now, then Dr. de Forest doubtless must Publishing Company, asking the Court to Chicago, Ill., all of which were advertis- have known very well that neither the punish it for contempt of Court for disre- ing three interior member vacuum detectors. Moorhead tube, nor the Tigerman tube, garding the injunction and thereby violat- As will be noted, these devices contain nor the Amplitron, all of which clearly pro- ing the dignity of the Court. "a heated filament, a cold plate and a grid fessed as being two interior member vacu- Here was a pretty mess. Remember, the interposed between the two former." The um tubes could possibly infringe on his Experimenter Publishing Company had tilt writer understood at once that the DeForest patents. He knew this well, for he has no December twenty- fourth to answer the bill Co. was within its rights by asking the patent on a two member tube. Neverthe- of complaint, nevertheless on December Experimenter Pubg. Co. to stop publishing less he swears to the fact that these tubes fourteenth an injunction was issued against advertisements of this nature.. Accord- infringe on his patents. Still let us give it I Not till the papers charging the Com- ingly the writer caused to be sent telegrams pany with contempt of Court were served at once to the three manufacturers in ques- did any of the officers of the Experimenter tion wherein the advertisers were notified Publishing Company know that Counsel . that hereafter no tubes of the character for the DeForest Company had been care- named could be less by forget- advertised in ting to fill in T H E ELECTRI- dates on his. C A L EXPERI- paper. MENTER. Making a That the Ex- ...-.. - ., \_ long story PERIMENTER had The Tigerman Detecto-Amplifier which Uses Two Filaments and Two Cold Plates in an Evacuated Tube. It Also short, the case kept faith with Uses Two Outside Members as Shown. c am e up for its promise is final hearing best demonstrated by the fact that in its Dr. de Forest the benefit of our many before Judge Mayer of the New York Fed- September issue (the August issue had doubts. eral District Court on January 13, 1917. gone to press during the controversy) no But now we come to the Lenzite Detec- Counsel for the Experimenter Publishing three interior member vacuum tube adver- tor. The advertisement in the December, Company was Mr. J. Edgar Bull. Mr. L. tisements have appeared. 1916, issue (on which the complaint is F. H. Betts seconded Mr. Bull. Mr. George The only vacuum tube advertisements based) shows that this detector is a min- A. Hoffman acted as general solicitor. carried since the September, 1916, issue eral detector, plain and simple. Its illus- By that time Dr. de Forest woke up some- were of the two member kind, which might tration shows it and anyone who can read what and before anything else was discust infringe on the Fleming valve but never on English can not fail to notice that even the Mr. Darby formally withdrew the Lenzite- the DeForest Audion. firm's name plainly reads: "Lenzite Crystal Detector from the case. It came, therefore, as a big surprise Corporation." The most cursory examina- The contempt motion was then argued at when, on December fourth, the DeForest tion must also show to anyone, beyond the ,length and the writer, as well as the Ex- Radio Telephone & Telegraph Co. served a shadow of a doubt that this detector can perimenter Publishing Company, were voluminous bill of complaint on the Ex- not be a vacuum detector. Nevertheless charged with bad faith. Mr. Darby sug

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 809 gested that in a case where the disregard side member" acted in effect like a grid and papers -with the exception of THE ELEC- of an injunction was far less flagrant than therefore infringed on the DeForest pat- TRICAL EXPERIMENTER, the largest and the in the present one, the defendant had been ents, the Court ruled that this was not then most influential of the lot, so admitted by fined $15,000 for contempt of Court!! established. de Forest himself. Judge Mayer, however, not only threw Our exhibit of the Moorhead Detector T II E ELECTRICAL out the motion for contempt of Court, but before the Court had only two members in E X P E R I M ENTER the original injunction as well. For he held a vacuous space. Our exhibit of the Tiger - feeling sure of its that the injunction order, because it was man tube before the Court embodied two grounds, accepted based on incomplete and faulty original of these Moorhead tubes joined end to end. a d vertisements papers served on the Experimenter Pub- The Court refused to enjoin the Experi- right along of two lishing Company, made the original order menter Publishing Company from accept- member vacuum void. ing advertisements of these detectors. tubes and its judg- Next came the arguments whether the This closes the case, which is of far - ment proved cor- reaching import not only to the manufac- rect. turers concerned but to all wireless ama- Thanks to THE teurs. ELECTRICAL EXPERI- The deForest Company, no longer MENTER-as well as able to sell Audions to amateurs, tried Counsel Bull, Betts by all possible, as well a5 impossible, and Hoffman-the means to stop the various manufactur- Wireless Amateur ers from making vacuum detectors, which as well as all others they claim in no way infringe on the concerned, have not valid de Forest Patents. becn deprived of Call it jealousy, discontent, or what not, efficient vacuum de- the de Forest Co. went out upon the prin- tectors-at least not ciple that if it could not make and sell for the present. The Lenzite Crystal Detector Which Dr. de Forest MORAL: Tu -be Claimed Infringed on His_Patents. vacuum detectors, no one else should. That by so doing they deliberately hurt the ad- or not to -be, that's Experimenter Publishing Company had ac- vancement of the art, as well as all ama- the evacuated ques- cepted advertisements which actually in- teurs, did not matter one whit. After it tion! fringed on the de Forest patents. was found that the various manufacturers Carrying out our promise not to accept could not be stopt, except by large expense, Consul Harry G. advertisements of vacuum detectors con- the simple remedy of intimidating publish- Seltzer, at Breslau, taining a heated filament and cold plate ers was resorted to. For, it was argued, Germany, report s and a grid interposed between the former, if the publishers of wireless and technical that one of the Bres- The Moorhead Tube Em- we consented to an injunction to that ex- papers can be sufficiently intimidated, they lau tinfoil factories ploying Two Interior tent, but the exhibits before the Court were will no longer take such advertisements has succeeded in pro- Members: a Heated Fil- samples of the Moorhead tube and the with the net result that the manufacturers viding a substitute ament and a Cold Plate. Tigerman Detecto Amplifier having outside will be driven out of business. for tinfoil by producing . incfoil. The new members. The scheme worked admirably well with product is similar to tinfoil and is suppos- Altho Mr. Darby insisted that the "out- all of the technical, scientific and wireless ed to render the same services. SPARK GAPS IN RUNNING sparking took place, and if the water flowed FULLER WAS FULLER. LIQUIDS. too slowly, arcing was produced instead of The following little anecdote, while in sparking. Even with the flow adjusted Dr. Eccles and Mr. Makower have ex- order to bring out the point makes it nec- so as to give the best possible results, it essary to use the actual names of the par- perimented with radio sparks in running was found that much energy was wasted, liquids. It was found, after using a va- ties involved, is too good to let slide by on owing to the losses arising from the con- that account. A certain correspondence riety of transformers and transformer ra- ductivity of the water. This makes the small gaps, within school, well known over the United States, tios, that for large or water -gap less efficient than an air -gap. recently had an exhibition booth at a cer- the range allowed by the bore of the tube, Using transformer oil instead of water, an required to pro- tain state fair. One of their means of at- much lower voltages were efficiency was obtained about the same as tracting attention was the installation of a duce the spark in water than were required that of an air -gap. It was found that wireless set, a rotary gap furnishing the for an equal length of spark in air. In when the oil spark was used, with almost noise necessary to draw a crowd. One of constructing apparatus it was ascertained any degree of coupling, some impulse ex- those connected with the exhibit went by that unless ample thicknesses of material citation was taking place. For example, that good old name of Fuller. He was a in were used, the pressures produced the when the coupling was 12 per cent, a single good sized sort of a fellow and chock full interior of the discharger during the pas- wave -length of 620 meters was observed in of puns, quips and jests, which were in the sage of the sparks, were sufficient to burst the primary and secondary circuits, and no habit of coming forth at unexpected mo- it. other wave -length was detected; whereas ments. Among the visitors at the booth, The most satisfactory design consisted of when the spark occurred in air, the same and a friend of the operator in charge of a cube of marble, with a side of about 4 circumstances gave two distinct wave- the set, was another wireless man, also by inches, provided with a vertical channel of name Fuller. This Fuller, however, was inch bore, thru which the liquids not by any means of the generous stature could be caused to flow; entering at the of the first Fuller, being by several inches bottom and flowing away at the top, so as smaller. It happened that the two Fullers to sweep away all the gases formed by the met in the booth at the same time, and the passage of the discharge thru the liquid. operator hastened to introduce them. The electrodes consisted of two horizontal "Mr. Fuller, meet Mr. Fuller." As the metal rods, with axes at right angles, form- two shook hands, Fuller the larger boomed: ing a spark gap in the middle of the liquid "Mr. Fuller, you're fuller than I am!" column. In order to prevent the liquid Fuller the littler looked highly indignant, being forced out by the high pressure de- as he is known to be of strictly temperate veloped, it was necessary to provide stuf- proclivities, and queried "How so ?" Came fing boxes at the points where the elec- back Fuller the larger, "Well, you're a lit- trodes entered the marble. tle Fuller !!" Now Fuller the littler is laying for illustration is a horizontal section Fuller The the larger and it is expected that there will of the discharger through the plane of the be a dual of wits when they again meet. A, electrodes, and shows the marble cube P. OARD. with the liquid column B, in the center and Gratifying Results Have Been Obtained With the electrodes C and D, entering at right Sparks Past Thru Oil and Water, the"Gap Design THIS IS AWFUL angles thru the stuffing boxes F and Illustrated Comprising a Marble Cube With a Liquid Column Thru It. Said the wireless man to a friend of his, F, and provided with ebonite handles G and Running a bookkeeper for the company in which he H, for adjusting the gap. The length of worked: "Never go to sea during the the gap was adjusted by rotating the handle lengths of 570 and 640 meters. The use of stormy season. It would queer you with G, and when the side of the electrode D oil presents the advantages of giving bet- your company." "How so ?" quoth the became pitted, a new surface could be ter quenching than the air -spark and of bookkeeper. "Why, you're apt to lose your brought into action by rotating the handle eliminating the deafening noise associated balance," said the wireless man, as he H. Experiments made with water showed with the latter, while the efficiencies of the ducked for the open doorway. that if the water flowed too quickly, no two forms of apparatus are the same. P. OARD.

www.americanradiohistory.com 810 THE ELECTRICAL EXPERIMENTER March, 1917

TRI -CITY RADIO LABORATORY. for equal audibilities, the condensation times stated as 40,000 per second in chil- Herewith is presented a photograph of needed at pitch 128 is double that needed at dren) falls steadily with advancing years. the experimental radio station -9XR. This pitch 256. In like manner the condensation Considering the results in their bearing station, that of the Tri -City Radio Labora- needed at 256 was 1.6 of that at 512 per on radiotelegraphy, it appears that we can, tory, Rock Island, Ill., has covered excep- second. Finally, the condensation neces- by increasing the spark frequency at the tional distances, both receiving and send- sary for audibility at 85 per second was al- sending station, increase the effective sensi. ing. The sending range on the Presiden- most precisely double that for pitch 128: tiveness of the receiving station many hun- tial Relay of October the 27th, was 1,085 Confirmation was also obtained by direct dred times. This can be done, too, without miles. Our message was clearly copied at comparison between the cans, of frequen- entailing the difficulties connected with an this distance, says R. Karlowa, operator. cies 85 and 256. Thus, to summarize: increase in the sensitiveness of the wire- Station 9XR is less receiver itself. equipt with the Hall An additional ad- Recording Relay. vantage in using a which permits the high -pitched musi- message to be cal spark is that the copied on tape or ear picks out such read from a stand- signals with ease in ard sounder. This the midst of ordi- is the only station in nary interferences this country equipt and strays. In spite with such a device of these considera- to our knowledge. tions. however, the (The Hall radio practise of some of relay was described the wireless tele- in the "Latest Pat- g r a p h companies ents" columns of and of certain na- the February, 1917, vies is to use notes issue of THE ELEC- not higher than 400 TRICAL EXPERIMENT - or 500 per second ER.-Ed, ) frequency. Pro - All of the arc longed trials of stations, as well as high -pitched notes the spark sets, are have shown that daily being recorded they tire the ear by this device. Un- rather quickly. d e r satisfactory conditions the op- MINNEAPOLIS erators are able to RADIO TALKS record the German WITH SAY - stations. VILLE. Besides two com- Wireless stations plete sets, one of at Sayville, L.I., which is shown in Darien, Panama, t h e photograph, and other distant 9XR is equipt with points on this conti- a wireless telephone nent communicated set ( Oscillion type) with the All- Crafts and a Fed- Club recently. The standard The Excellent Radio Set at the Tri -City Radio Laboratory, Rock Island, 111, It is Equipt With the eral receiving cab- New "flail Recording Relay," Which Enables the Operator to Secure an Accurate Copy of Every Mes- event was the an- inet. sage on a Paper Tape. nual meeting of the club at the Minne- SENSITIVENESS OF THE EAR. N...512 256 128 85 per second apolis Athletic Club, at which a wireless Relative value of s....1 1.6 3.2 6.4 Rayleigh found the sensitiveness of the receiving outfit had been set up. ear to sounds of different pitches to be as Thus the differences of sensitiveness are The club meets every Tuesday noon at follows: less than those found by Wien. The sen- the Elks' Club for luncheon, except once sitiveness of the ear varies greatly with it N e' (256) g' (384) c" (512) during the month, when meets at the age, and the upper limit of audition (some- a e 60x10.94.6x 10-s 4.6X10.8 Athletic Club for dinner and lecture and demonstration of some scientific or mechan- where s is the condensation (or rarefac- AEROPLANES TO CARRY SPECIAL ical phenomenon. Wireless telegraphy was tion) in the air required to cause an audible WIRELESS DYNAMO. the subject on this occasion. Mark Frazer impression, states Dr. Eccles in his Hand- The accompanying illustration is that of and James A. Coles were the demonstra- book of Il'ireless Telegraphy and Tele- a new wireless telephone generator for use tors. Their outfit was capable of picking phony. Here the condensation is the maxi- especially on aircraft. up European radios had the atmosphere mum which occurs during the course of a It is a special generator or dynamo for been propitious. vibration. The method employed depended wireless telephone transmission and recep- upon a knowledge of the rate at which en- tion for use in aeroplanes only. It is a ergy was emitted from a resonator under combination of two direct current genera- AMERICANS USE WIRELESS excitation by a freely vibrating tuning -fork. tors mounted in a torpedo- shaped shell, FREELY? one of the generators delivering low volt- In a careful re- examination of this ques- filament Garrulous American sea captains, talking tion, Professor Max Wien, working with age for lighting the of the re- with each other by wireless, have brought the telephone, finds not only a still higher ceiving Audion, while the other delivers down on their heads the wrath of Austra- degree of sensitiveness, but also a much lian government officials, it was learned more rapid variation with pitch, as shown recently. by the following figures: Complaint has reached Washington that American ships 2,000 miles apart in the N N south seas discuss trivial subjects, when the s s Australian wireless is trying to get into the air important messages. 50. . . 1.14X 104 1,600 0.99X 10.11 . . Special Wireless Telephone Dynamo Recently captains declare that anti- 100. 0.78X 10-8 3,200 0.90X 10-11 Developed The American 200. .. 0.71 10.8 6,400 1.63 X1041 for Use on Aircraft. It Combines Two in in Aus- x Dynamos, One Giving 6 Volts 1500 quated wireless equipment use 400 .. 0.85 X 1048 12,800 5.7 X10-11 and the Other They 800 .. 1.63X10-11 Volts, For An Oscillion. tralia is to blame for the situation. deny that trivial messages have been ex- 1200 to 1500 volts, direct current, for trans- changed. In this table, N, indicates frequencies and mission. Both armatures are mounted on The Australian charges are being investi- s, condensations in c.g.s. (centimeter -gram- one shaft and supported at both ends by gated by American government officials and second) units. To test the question further, ball bearings. The outfit is intended to a curb will be put on the practise if it is Rayleigh experimented in a new way, using be driven by a small auxiliary air pro- found that the wireless is being used for a retal cans maintained by electro- magnets as peller. The outfit has been tested and too free exchange of unimportant mes- vibrators. The experiments showed that approved by the U. S. Navy. sages.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 811

helpful to all fellow radio workers. New Undamped Wave Tuner Has Adjustable Disc Core One of these amateurs is IZU, who is HliREWITH is given a description of as to permit all required position adjust- recognized as thc only amateur working a new Undamped Wave Receiver de- ments by sliding and rotating the shaft sup- any great distance who lives in eastern signed by Ernest C. Mignon, the well - porting it. Massachusetts. known radio engineer. The object of the metal Distorter is to Another is 1ASD, who has heard a The object was to eliminate all unneces- control the fields of distortion and to fa- number of amateurs in Illinois, Michigan, sary apparatus such as loading -coils and cilitate' a decrease or increase in wave Indiana, and Ohio; and who has worked length without thc cut- 100 miles with a % K.W. transmittcr. ting in or out of coils Contributed by or condensers, making it possible to intensify sig- A SIMPLIFIED CODE. nals to more than 65 per On page 175 of the July issue of the cent of their ordinary strength. 0,x control oandkr The Auto- Transform- and tuning PC csn/ro/ --MU tl- - I ,r er encircling the detector s bulb has been fully de- LAMIT_sMO. scribed in a previous is- i . sue of THE ELECTRICAL /,. EXPERIMENTER. One remarkable fact is Cod that only one size of wire is employed in this C_ new system, primary and secondary being the ilea/ disc same, and the smaller or finer the more efficient the apparatus, which fact Side Sectional View of New Undamped Wave has been positively as- Tuner Having Adjustable Disc Core. certained by extensive Appearance of Recently Perfected Undamped Wave Tuner, Which Operates on a New Principle -That Involving a Variation in the experiments in the labo- "E.E." an article appeared describing a code Magnetic Coupling, by the Use of a Movable Disc Core. ratory. composed entirely of dots. Such a code is Another important useful to those who wish to tap signals loose- couplers and above all the distortion feature is that the well -known detrimental thru a wall, along a pipe, etc., without the of the magnetic fields in the tuner by the effects in other systems due to the close use of instruments. When the number of proximity the hand of operator's or body. proximity of the different circuit induct- dots constituting a letter is greater than The first step was to build an inductive ances, are entirely eliminated and the ca- five this code is, however, difficult to send tuner, consisting of three distinct windings pacity of the operator's body has absolutely and still more difficult to receive. For or coils, namely a primary and two inter - no effect on the incoming signals, it is those who are already familiar with circuited secondaries, all three identically the claimed. Continental or Morse code, a much simpler same, ring- the shaped and supported in system is available. This system also grooves cut into insulate discs, containing saves learning a new code. The only the same amount of wire and sections. change necessary is to substitute These two dots three ring-coils are then solidly for each dash, i.e.: mounted on the same plane in clover shape, instead of facing each other, as in all oth- er systems, which is accurately illustrated in the accompanying illustrations. C .. . This is much easier The magnetic fields of all three coils are to read and will be found equally efficient. The idea interlinked with each other thru the cen- will prove of advantage such ter of each of them and may be pictured as to organizations as the Boy Scouts. rings or as called hereafter by the inventor, Contributed fields of distortion, and which for the first by F. C. HAMILTON. time since the history of wireless signaling A NEW FLAT SWITCH POINT has been made use of to advantage and FOR TUNERS. proved to be of the greatest importance for -,= . :..._.... The new flat switch point here illustrated future development in radio telegraphy and BOCA' kg?" rr is a marked improvement in switch points. telephony. They are made from flat stock, of brass The fields of distortion are identically of Rear View of New Undamped Wave Tuner, Show- 1/16" thick and % inch long under the head, same dimensions ing Position of Three Coils and Movable Disc Core. the as that of the actual which makes it possible to get a great coils and facilitate an increase of approxi- many more points in a given space. These mately 100 On an aerial sixty feet long and per cent in the wave length ca- thirty points when mounted present a very neat pacity; in other words, it requires only one - feet high, signals from stations 9,000 miles appearance. They are made slightly ta- away have been half as much wire to build a tuner for a recorded, which were by pered, which holds them securely place. means in certain wave length of this type, as it would no weak. It is but necessary to drill the holes in the any for other. manner shown in the illustration, that is One of the features in this invention is AN EFFICIENCY SUGGESTION to stagger them. The switch points are FOR "RADIO- BUGS." driven in and the connections are soldered Lately several young men who are studying radio engineering at a nearby university have moved their entire amateur receiving and sending apparatus to the cellar, near the water meter. Their idea is to get the shortest possible ground lead. One youth, whose cellar is too damp to operate in, has his sending set in the cellar but has his receiving set, key, etc:, almost directly above on the first floor. The results of these changes were sur- prising as well as gratifying. One amateur A Flat Point for Multiple Switches Permits previously having his set in the attic, in- Maximum of Contacts in Minimum of Space. creased his radiation from 1.7 amps., to 2.2 amps., without touching the closed cir- cuit and by simply putting the open cir- on the reverse side. These switch points, cuit in resonance once more, after the owing to their extremely small bulk, cut Circuit Connections for Vacuum Detector and down the distributed capacity in an instru- Adjustable Disc Core, Undamped Wave Receptor. change. These amateurs are considered among the best in this part of the coun- ment more than half, their inventor claims. the Metal Disc or Ring Core, called by its try (Massachusetts) and this little "tip" This is an extremely valuable feature for inventor a Distorter, which is so installed past to me by one of them, should be serious long distance work.

www.americanradiohistory.com 812 THE ELECTRICAL EXPERIMENTER March, 1917 The Calculation and Measurement of Inductance By H. WINFIELD SECOR and SAMUEL COHEN PART I. This discussion on the calculation and The Henry is the unit of inductance. A ance of a single antenna wire whose length measurement of inductance is intended for circuit is said to have an inductance of is 400 feet and the radio one diameter .08 inch. Con- experimental and other readers henry, when the current is changing at the verting the above units into centimeters who desire to compute the proper size of rate of one ampere per second and inducing and substituting in formula No. 1, we get: tuning coil or loose coupler to use for a a pressure of one volt in the circuit. One certain range of wave lengths. Part 2 of henry is equal to 10° or 1,000,000,000 (cen- L= 2X( 400X30.48) [2.3026 l0g104(400X30.48) 1] this series will explain in simple language .08X 2.54 timeters) C.G.S. electromagnetic units = 24384 12.3026 X 5.38021 - 1] (C.G.S.) is the centimeter-gram -sec- = 27,766 cm. or .000027766 henry. ond system; 1 milli -henry = .001 hen- It is therefore possible with the above ry or 10° centimeters. Henries times formula to determine the self -inductance of 10° = inductance in cros., and induct- a single antenna wire. The result obtained ance in cms., divided by 10° gives the with this formula is approximate as it does result in henries. A coil is said to not take into consideration several factors have 1 C.G.S. unit of inductance such as curved or bent portions of the lead - when 1 C.G.S. unit of current flows in, etc. The surrounding objects about the thru 1 turn, producing 1 line of force. wire have an appreciable effect upon the Let the current in amperes be I, inductance also. However, for approxi- number of turns in coil T, and I. mate results the above equation will be number of lines of force due to coil, found useful. then we have for the henries of in- The common formula given in text -books ductance of the coil the expression: for computing the inductance of coils hav- ing a length at least 20 or more times the L 10x1' diameter is given here: The self-inductance of a single, L 10,028 X R. X T° e 10i' l (2) Fig. I. Appearance of Magnetic Field About a Coil of straight round wire can be deter- X Wire Carrying Current. "Inductance" Is Exprest as the mined by the formula: Where L is in henries; R the mean ra- Opposing Effect of the Self- induced Current, Created by dius of coil in inches; T the total turns in the Magnetic Field Reacting Upon the Coil. L =21[2.30261oz,0d (t) -I] coil; 1 the axial length of coil in inches. Result in inductance centimeters. cros.= henriesx10°. For coils how Inductance is measured, while Part 3, where L- in containing iron cores the inductance length of in centimeters. must the final paper, will conclude with a practi- 1- wire be multiplied by the permeability, found in cal design of loose coupler, adaptable to va- all magnetization tables. rious wave length ranges. The day of the The most common form loose coupler is here, and here of inductance I2,000 meter b that the amateur is familiar with is that of to stay. a straight cylinder with a certain number ALTHO a considerable amount of =O of turns on it. The inductance of such a data has been publisht on the sub- c +OOO+O0004 coil can be found by substituting its various ject of Inductance, very little has dimensions in the following expression: - been said regarding its calculation ' _ 0..W.0.0.0 Q (5XdXN° and measurement in a simple 0 a enough manner to enable the experimenter L S d (3) 3 to determine the inductance values of coils r which he has about his station and labora- O,Y/S Where: L= inductance in centimeters tory. It is therefore the purpose of this d= diameter of coil in inches article to show as clearly as possible the N =total number of turns method of finding the inductance of a given S = length of coil in inches. coil, both of the single and multi -layer Example :-Suppose it is necessary to find types. O+O'O+O'O+OO O' the inductance of a coil whose dimensions Firstly, it is well known that whenever an 00+000000 are as follows: 12 inches long, 3 inches in diameter with 250 turns of No. 18 electric current passes thru a conductor a ;OO*OOO OO Ó 2 wire. magnetic field is produced about that con- 0t00.0 0 00.0 fi9 Substituting the given values in the above ductor. Fig. 1, and the intensity of the field equation we get depends upon the current flowing thru the ® L (3XSX250)° = 3,004.807 ems. wire. Those magnetic lines of force about Showing Geometrical Dimensions of Coil as Used the wire produce an e.m.f., passing in the in Calculating Its Inductance by the Brooks - 12 +- opposite direction to that of the imprest Turner Formula. e.m.f. The above coil has an inductance of desired The effect of this is to counteract the im- d= diameter of wire in centimeters. 3,004,807 cms. and if the result is in prest current, thus decreasing its value. Suppose it is required to find the induct- microhenrys it is only necessary to divide This counter e.in.f., acting upon the whole r 4o/ues b- Io.uo/ /enq/h co7 electrical system is called "self inductance" /0 70 30 e0 so co O do s0 roa and every conductor irrespective of its li shape, length or size, has some self- induct- ance. However, the amount of inductance of the conductor depends upon several fac- tors. namely: shape, length, diameter of , conductor and the amount of current flow- is usually ing thru the wire. This last term ; \\ \ Shope fat-forearms eliminated in actual inductance calcula- p.m az) n.isnro far values off'f" tions, especially in coils which are con- high frequency oscillating cir- ° o nected in V cuits. "Brooks - Turnei-' Since the magnetic effect of a conductor formu/o carrying an electric current is increased 0 when the wire is formed into a circle and omeonrodirsafcoi/ since the self -inductance depends upon the number of magnetic lines of force pro - c/hicáness ofcoi/ duced, it is self- evident that a circular con- :t ductor of the same length and same size R. loy» /ha cose has a larger self- inductance value than a straight wire. It is readily seen therefore f93 why circular coils are employed instead of I I I I ® long, single conductors. With compact coils Direct -reading Curves Giving Var'ous Values of Product F F ", as Used in the Brooks- Turner Induct- the magnetic field is more concentrated. ance Formula, and for Varying Dimensions of Coils.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 813 the answcr by 1,000, thus giving 3,004 mi- Where:-L= inductance in henries containing any number of layers are cov- ered by it also. crohenrys. a = mean radius of winding The above formula will hold true when The direct reading inductance curves at the coil is very long (length 20 times diam- h= the axial length of the coil Fig. 4 have been calculated by the authors eter, etc.) and when the answer is not re- c =the thickness of winding; for from the Brooks equation (No. 6) and will quired to be very accurate. The formula single turns use (d) dia. of undoubtedly prove useful to the radio and given below will prove more accurate for a wire in inches electrical experimenter as these values have coil whose diameter is greater than its not been given before to our best knowl- length. This equation A. Russell: R = the outer radius of the wind- ing edge. The two windings have been chosen so that one may select suitable length coils (,DN)sll l (4) L` 3s L +8 \, /= .671T J Cm = indicates the length of the for use in building small and medium size Where: L= inductance in centimeters conductor in centimeters loose couplers, tuning coils and variome- D = diameter of coil in cm. Ft = the length of the conductor ters. N = number of turns per cm. in feet and Ft /1000 = thousands For the inductance values of larger size 1= the length of coil in cm. of feet coils suitable for extra long wave reception Altho the above formula is quite accurate for calcu- lating'the inductance of a coil of any length, there are still two other formu- EIBILI lae which are very accur- [rrrnraur.rrar 1 ' ate for any size coil, even .10czL.Gilà&E\m ....e.mi/a10.1 míwí.Si those having a length of .1111111110.1110..lr..i one -tenth the diameter or ...10.11111011.11...10iriolPinm10ii.I- a single turn. 1111.101111..10PraI/5s11 The first of these is due ...11..10.KI11Cí.101 to Nagaoka, who has devel- 11.11101111!í.!n1010.1010.i oped a very simple equation ...10..íPrailEWM...... 1 as follows: ...10Li11.10 -a)íI!í1d1/0". L- 4.an.bk; (5) ia!í111 Where : -L = inductance o f 11101 sIf: ty0a O/ENO10IMÌ re uo coil in centi- 1111111011 0.-e(5...i, d°m ...... b .10.10.1 meters. ..r..11i/"`i¡ .11101ff1 a= radius of coil 1111111111/i/i Inductance curves for single 10C1 center of / 1.11..11.... 11. EM ENI to .1La , oar core cods 10.1 wire, in centi- 11I meters (mean s 1 radius) 1110Í:a.11.1011..11.11101011.% %iiaon om:emÌ ....11...1110.I n= number o f 10..10..10I turns of wire ...... 10...10..101011010111010.10..101 per cm. length .11101110. 10 of coil. iiiiiiiiiiiii:iiiiir11r.r.-+:1111.....a...1 b = length of coil in centimeters. K= a constant. The only difficulty en countered in the use of this Direct- reading Curves for the Inductance in Centimeters of Typical Loose -coupler Primary and Secondary Windings. well -known formula is that involved in the constant, K, the value of N =total number of turns in the and the method of figuring the desired which must be obtained from a table. The winding, whence amount of tuner inductance, with respect table gives correction factors for different Cm= 2waN when (a) is in cen- to the electrical constants of the antenna, lengths and diameters of solenoids. It timeters and the reader is referred to the article by Mr. does not take into consideration the so- Ft 2s. aN C. Ballantine, entitled "The Design of called current sheet effect, which is the 1000 12,000' Large Radio Receiving Transformers" in effect due to the leak between successive when (a) is in inches. the February issue of THE ELECTRICAL Ex- turns of wire. (See end of this article.) In (7) the conductor length is in thou- PERIMENTER. For accurate calculations the formula is sands of feet and the coil dimensions in In using the Brooks universal formula. one of the best that one can employ. These inches while 0.366 is the conversion fac- the factors, F' F ", may be disregarded for tables are quite large and space does not tor. F' and F" are empirical coil -shape long coils and for approximate results the permit us to publish them here. However. factors, dependent upon the relative and in- formula reduces to:-(L in henries). and Cm. those readers interested in this formula dependent of the absolute dimensions of (10) tables can refer to pages 224 and 225 of the winding. The values for these two L (b+c +R)10' the Bulletin of the Bureau of Standards, factors are obtained by the following ex- QrLin gyms.= Vol. 8, No. s, by Rosa and Grover, 1912. pressions: (b +c+R)' (11) A new universal formula for determining 10b The can still be reduced for F' +12c +2R equation the inductance of any coil, absolutely irre- 10b+10c+1.4R (8) very long coils, since "b" becomes so large size shape, has been spective of its and de- F" _ .05 kg,,, (100 + as compared with "c" and "R," so that duced by Professor Morgan Brooks. The 26+34R (9) equation (10) becomes: (L in henries). equation which he has developed is appli- The notation of 'the different functions (12) cable to all sizes of : olenoids. This formula used in the first two expressions can be - 609'X1 has been carefully checked for coils whose more readily understood by referring to ans. (13) inductance was measured and also calcula- Fig. 2, which is a cross section of a sole- QrLin =Cm. ted by other standard precision formulae noid. The curves of Fig. 3 enable one to The above expression will be accurate such as that of Stefan and Kirchhoff for select directly the value of the product F' within the limits of approximation with coils of but a single turn. It was found F ", for a wide variety of windings, from coils whose length is ten times the diameter. that the results obtained differed infinitesi- those having a length about three times the It may be used to advantage in calculating mally from those obtained with Nagaoka's mean diameter to those whose length is but the inductance of spiralled antennae. formula. 1 /300th the diameter. These shape factors In order to become more familiar with Two forms of the Brooks universal for- given by Fig. 3 are relative functions only, the use of Brooks' formula, we will illus- mula are herewith given. One in which the as becomes apparent and are not in inches trate it with a typical problem. Let us de- dimensions are in centimeters and another or cms., but serve for computations in either termine the inductance of a variometer coil in which the English units are used. Both system. The Brooks formula is accurate whose length is one inch, diameter 6 inches give results in henries. to a small fraction of per cent in most and wound with a single layer of No. 20 all instances, even for coils of a single turn. cotton covered wire. Cm. F' F" double X (centimeter units) (6) In the case of a tested (single turn) coil Ft 2X3.1412,03.016 X25\ b+c+R 10. V ( =.001521 the calculated value of inductance by this (100/ (12,000/ 9 12,000 Ft formula was only -0.88 per cent in error, 0.366(.001521)L= xFF 0.366 (1000 which of course represents the extreme test 4.064 = X F, F" (English units) (2) b +c +R for any formula of this nature. Solenoids (Continued on page 85o)

www.americanradiohistory.com 814 THE ELECTRICAL EXPERIMENTER March, 1917

connect the terminals of this coil to a sensitive Is Radio Transmission Due to Magnetism? galvbnonieter and if the total resistance of the complete circuit is 5 ohms, then the electrical By J. S. CLEMENS energy induced in this circuit by the magnetic earth flux passing thru the coil axially when it is The writer has lookt up different ex- graph and telephone signals will also fol- reverst in position will be 3.010 -6 coulombs. planations in several text -books as to the low the curvature of the earth. A piece of iron placed in the neighborhood of the readers of THE a magnet becomes itself a magnet. Now the exact theory on which wireless telegraphy Possibly some of earth is magnetized and therefore all Pieces of is based, but none of them seem to explain ELECTRICAL EXPERIDIS;NTER will give their iron may be expected to show signs of induced the matter very thoroly, and I would there- opinion as to the exact theory on which magnetism. To illustrate this perform the follow- also telephony. ing experiment. Take an unmagnetized rod of fore like to submit my opinion, which is wireless telegraphy, wireless soft iron. staid it horizontal in the plane of the as follows: [Address all communications to the Edi- meridian and tap it gent! with a hammer. Now We all know that a compass needle points tor.] test both ends by means of a compass needle. You [Editorial Note:-The theory in- will find that the end which pointed north repels volved in the above discussion by the north end of a compass needle. The rod has Mr. Clemens is very interesting and therefore been magnetised by induction from the possibly brings out some rather earth. To demagnetise the rod, hold it horizontal startling natural electrical and mag- pointing east and west and strike it a few times netic phenomena but little known to with a hammer. After it is demagnetised, hold it framerecn0 the average person or even to the vertical and tap it again with a hammer. It will frame electrical experimenter in many in- become magnetised again and the North Pole will stances. be at the lower end. If you care to take the The accepted wireless theories of trouble you will also find that practically any Woad to-day which, of course. are little vertical piece of iron -a pillar, rail or gas pipe - more than theories, are based on it magnetised with a North pole at the bottom. hobbit the supposition that the electromag- netic waves set up by a wireless CONDENSER AND SWITCH HINTS. Coif transmitting station are propagated thru what is known to scientists as Thick slate for the base of a home -made the ether. These waves radiate con- lightning switch is very hard to obtain, but centrically in a ripple -like forma- two thin pieces, A, may be used as shown tion from the radio sending station in in much the same manner as the the cross -section view. The two pieces waves ensuing from a stone dropt may be cut from an ordinary school slate. in a quiet pool of water; the grad - The holes at B B B, for the switch posts, ually expanding waves eventually are drilled the top piece reaching the receiving station or the thru only, and the shore, as the case may be. holes, C C, for the wood screws are drilled However, a very interesting and thru both. ever-present natural phenomena is A good way small receiving that of the terrestrial magnetism to mount a manifested by the earth and which condenser is shown below. The top and lends itself to a number of inter- bottom pieces are of thin, polished wood esting experiments, aside from that %" larger than the condenser all around. of the several interesting actions occurring in using the well-known They each have a hole bored at the ends magnetic compass. We know that and holes are punched in the condenser lugs the magnetized steel needle of the to correspond. Two brass bolts, AA, from mariner's compass always points to- .I ward the north magnetic pole of dry batteries (the lengths of the bolts are the earth. greatly exaggerated in drawing) are thrust Turning aside from this 'well - up thru the holes in the bottom and the known phenomenon. we come to a very interesting aid, albeit, a prac- nuts, BB, are screwed on. The condenser tical consideration which involves is now slipt on and the washers, CC, and To Demonstrate the Earth's Magnetic Field, Use Is Made of an the actual production of an electric the nuts, DD, are screwed tight against the "Earth" Coil, Shown in the Illustration. This Coil, which May current directly from the cutting of lugs so as to make good contact. Put the Be Turned or Revolved in Any Plane, Is Connected to a Sensitive the magnetic lines of force emanat- Galvanometer. An Experiment That Every Young Electrician ing from the earth's surface. Inso- top on and tighten up the nuts, EE, turn Will Find of Extreme Interest. far as we know, the earth is actu- down the nuts, FF, and your condenser is ally a gigantic natural magnet. complete. North and South, demonstrating that there The earth has o magnetic field, the intensity and direction of which are different in different Contributed by ROGER HACKNEY. is natural magnetism in the air. To prove places. In England the field is northerly and that there is magnetism in the air all that inclined to the horizontal at an angle of about is necessary is to take an iron rod, approxi- 67 degrees. An ordinary compass, by the direc- tion in which it points, shows that this field is mately 12" long, " diameter; wind two northerly; it fails to show that the field is not layers of No. 20 or No. 22 magnet wire horizontal because it is so mounted that it can around this rod and connect the two ends of only swing round in a horizontal plane. If it were free to tilt it would point with its north this coil to a galvanometer. pole downwards at about 67 degrees. By holding the coil at one end and wav- Consider now a North pole of unit strength. ing In England this will be pulled northerly and it to and from the ground, the galvano- downwards by a force of about half a dyne. Re- meter will register a positive electric cur- solve this force into two components (Fig. t); the rent in one direction and negative in the other. one, (V) vertically downwards, the other, (II), horizontal and North. The latter is called the This goes to show that there are lines of horizontal component of the earth's magnetic force in the air which reach from the North field; it is usually denoted by the Symbol H; to the South poles of the earth. By wav- its value in London is about .186 dyne. It is this horizontal component that regulates the behavior ing the coil you cut these magnetic lines. of a compass needle: the vertical component has All that is necessary to transmit signals no effect upon it. is to excite these magnetic lines that are Most college laboratories and high schools are equipt with what is known as an earth coil or A Good Way in which to Assemble and Clamp already in the air by a higher voltage. The earth inductor (Fig. e). .These are generally Condenser Leaves. higher voltage would excite these lines of mounted pivotally on a suitable frame or base so force and turns them into magnetic waves. that they can be turned slowly or at fairly high speed, the coil being mounted as shown in the These waves can be pickt up at a distance illustration. with any wireless receiving outfit. This ex- if we assume that the coil consists of N turns planation I believe to be the theory of of wire of radius A cos., and that the total re- sistance of the inductor, and sensitive galvanome- 11;:l wireless telegraphy, also wireless telephony. ter connected with it, is R ohms, then when the In wireless telephony the magnetic lines coil is placed at right angles to the earth's field, ////%J///%t////717(///i r////.:r////. in the by an arc. To demon- the horizontal component of which is H= (.t8 air are excited dyne, the number of lines of force passing thru strate this I might state that if you take a the inductor will be: H N. pr A', in which pi = magnet and hold it to an electric arc the 3.1416. magnet will blow the arc but when If we turn this coil thru go degrees, in order out; that it shall face East and West, no magnetic Making a Suitable Lightning Switch Base from the arc is burning in the air the magnetic lines of force will pass thru it. Hence, the elec- Two Thin Pieces of Slate. lines of force in the air are much weaker trie charge driven around the circuit will be: if you holding a magnet to the than were OA* NH WELLFLEET RADIO OUT OF arc. Realizing that the lines of force are 10'R ' weaker than the arc itself, the arc will have COMMISSION. a tendency to create magnetic waves, or in If we turn the coil thru z8o degrees, the elec- The high -powered radio station here of other words vibrate the already existing tric charge would have been double this; but if the Marconi Wireless Telegraph Company thru an arc of 36o degrees then, it would have America was out of commission recent- magnetic lines in the air, when modulated been zero, as the current would have reverst dur- of by the human voice. ing the second half of the revolution. ly as a result of a severe storm. High The magnetic lines of force follow the If such an earth coil is constructed having an winds wrecked the antennae of the plant area of 5o sq. cms., and 4o turns of wire, then number of wires of the Western curvature of the earth, as the earth is a when it lies flat upon a table the flux passing thru and a magnet, and consequently wireless tele- it will be equivalent to 86o maxwells. If sow we Union Telegraph Company.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 815 The Quenched Spark Gap By CHAS. S. BALLANTINE, Radio Research Engineer URING the past five years the mosphere, composed of about 80 per cent and consequently the adjustments for good gap has practically 19 nitrogen, per cent oxygen and 1 per working conditions are very much simpli- been adopted for commercial cent argon and other inert gases of this fied. It is regrettable work that this condition is by the various radio com- group, in the gap is decomposed by the an exception rather than the general rule. D panies and seems to be giving spark into nitric acid from the nitrogen and In the following discussion it will be as- complete satisfaction, both in regard to water vapor, which unites with the metal sumed that the operating efficiency current supply is drawn and the reduction of of the gap to form nitric oxid gas. Under from the city mains, and that the phase decrement of the radiated oscillations. A certain conditions other chemical reactions device such as this, which has past the test may take place, but the final result in any case is the reduction of pressure in the gap and the absence of oxygen in the suc- ceeding discharges. Owing to the fact that all metals contain a certain amount of occluded gas, it is necessary to season the gap, by allowing it to operate continuously for a few hours before the note or tone finally becomes clear. If the gap leaks and air is constantly being admitted to the sparking chamber, its presence may be de- termined by the appearance of the spark- ing surface, which oxidizes Arrangement of Apparatus for Determining rapidly and be- Operating Characteristic of Resonance Trans- comes covered with a black deposit. former. If this occurs, the gap should be thoroly cleaned Connections for Quenched Spark Radio Trans- of actual operating conditions of all kinds, with alcohol and a piece of crocus mitter, as Described in Present Article. must certainly have sufficient merit to war- cloth or very fine sand paper, taking care rant its universal adoption. to remove all fine particles of foreign mat- relations of the very ter currents reaching the pri- In amateur circles few of these gaps before reassembling. The gaskets should mary circuit are unknown. The author has are seen, principally because of the cost of be examined and cleaned and if they ap- used the following method of adjusting their construction and on account of the pear to be perfect, the gap may be reas- the transmitter for some time, with excel- fact that the few who have tried lent results: a sufficient them have not made To begin with, it would be study of their operating char- well to point out to results that the meth- acteristics attain the od described is one that can be that should be obtained, and applied to any transmitter, but hence have condemned them is particularly useful when the from the start. The expression quenched gap is employed, as it of such an opinion, founded on is absolutely necessary to have nothing more than a cursory ex- perfect resonance conditions in amination of their merits, of all circuits with this gap. Oth- course is only a display of igno- erwise the inferior results re- rance which is shown now and ferred to in the opening para- then by a few experimenters, graph will probably be obtained. but its effect has been quite ex- The apparatus indicated tensive. The author knows sev- in Fig. 1 are arranged as follows: eral people who have never used T represents the low frequency a gap of this sort, and in fact transformer, preferably of the have never seen one, but who closed core type. An ammeter from the start have exprest their is connected opinion of it very forcibly. It in the primary cir- helping cuit as shown at A. The react- is with the intention of ance Rp is inserted in the pri- to correct a few of these falla- mary. The secondary reactance cies regarding the quenched gap shown may that the following paragraphs at Rs be omitted, as Working Drawings for Building an Efficient Quenched Spark Gap, as its effect on the circuit is slight have been attempted. Described by Mr. Ballantine. as compared with that of Rp. The quenched gap, as most of This may be seen from the vec- us know, consists of a number of very short sembled, using a little more pressure to tors of the ideal transformer. Further, gaps connected in series and made air- tight. bind the plates together. If the gap still any resistance inserted in the primary side During the period of the first few sparks continues to leak, replace the gaskets and of transformer has an effect equivalent to across the gap, the oxygen of the air in- test it again. Further failure would seem (Co itinued on page 855) cluded in the gap is burnt up. What prob- to ind.cate that the gap was mechanically ably akes place is as follows: The at- defective. 7 1 In.... In regard to the en- M...11 gineering aspects of C.....:...r71. 1011107u quenched gap opera- 6 4 tion much has been 1111 ...... 7...... 10//N10 P07J.7.+ì+7,5ll\1 1 10rY written, and it will be Ion Innu1010 only necessary s unr o rfEJVi1H to re- .I si,;110101010 view a few of the ba- u sic principles here. 47/%1NLli%//!1Y 'M E/ ° 1 .11I%%/!Iu In the operation of ..rT!1.1.11 11/5E11111i%2!1111111 this gap the conden- ser capacity a n d' n 0.....4...... fJi1 11 111'9'///ÚI11M= Z = 3CCC9"""'C:.S.,,,,.,,,,==7=C:C==!1N phase relations of various 11.11...... 7 fi.... iiiGGiniiiiiGii!iG the currents . c f11H///'///./MiLí11111111111111111111i7u%//%//.11Ri1111 in the transformer u are of great impor- 11....111111111\1 tqH%%OIIII11 tance. ll 1 2 Generally the 1 rNu%%%10 amateur must accept 1 .... lali%/iilC1110 n 1 J his current as he re- L1n70Hr/,M1 1 10HA1010 ceives it, when the n HIA1111111111 supply is drawn from 4 i ü...... á...Wal.r 11HII10f1i=3; the city mains. In . 11i.1161 cases where the gen- O 1 J 4 s s 0nI310101111I / 1 3 _ . 4 S 7 erator is located near Seporalio. °feeds Pr/mory Rf Rem-fa/Re the apparatus, some Graphical Representation of Maximum Coupling Graphs Showing Oft Resonance Operating Conditions for Well -Tuned control may be had Permissible for Typical Quenched" and Ip Quenched Spark Set. over its operation, "Rotary" Gaps.

www.americanradiohistory.com Sib THE ELECTRICAL EXPERIMENTER March, 1917

of 0.088 M.F. made in this way was 400 Oddities in Telephone and Radio Receivers megohms with 110 volts, and 250 megohms THE design of telephone receiver in- of the signals, by variations of the inter- with 240 volts. \ ented by S. G. Brown is shown in nal capacity or of the aperture. They The charging or polarizing voltage is plan and section in Figures 1 and 2. have proved of but little use with spark of great importance in relation to the vol- Here A is the casing and B the ear -piece, signals, perhaps for the reason stated in the ume of sound given by the receiver. With while E is a steel reed, of which one end last paragraph. 240 volts the authors found that the vol- 's fixed to the bridge -piece E' on the cas - Electrostatic or Condenser Telephone ume was equal to that of an electro-mag- ng A, by two adjusting screws E2. N and Receivers. netic loud- speaking receiver and increased The speaking condenser, since its discov- substantially with voltages of 300 and 400 ery by William Thomson in 1863, has been volts. investigated and developed by a number The variation of capacity with frequency of individuals. Pollard and Gardner used has also been investigated. The capacity a polarized condenser as a telephone re- was measured between w -1,800 and 6,000 ceiver in 1874, two years before the dis- by the Anderson method, and no variation covery of the electro- magnetic receiver by at all could be detected, whether the charg- Bell and Gray. Dolbear in 1879, however, ing potential of 240 volts was applied or was the first to obtain good results. not. This is in contrast with the electro- Further progress was made by Dr. Cornel- magnetic telephone, whose inductance and. ius Herz and Dunand in France. With effective resistance vary considerably, in a condenser of 5 M.F. to 10 M.F. capacity, consequence of the natural vibration of the Herz is said to have succeeded in com- diaphragm. The condenser telephone has municating between Paris and Orleans and no mechanical natural period. Each of the . between Paris and Tours (1881). Since rubber diaphragms has a period of its own, 1881 J. W. Giltay has contributed consid- but the periods of the separate diaphragms erably to the theory of the speaking con- are all different, so that no definite natural denser (1884, 1897). His investigations vibration of the whole system is possible. deal principally with the polarization of the Moreover, the disposition of the several . condensers, and he has shown that unpol- layers gives such good damping that they arized receivers reproduce all sound an vibrate aperiodically. There is no rattling,. octave above the original. as in the electro- magnetic receiver. Such Workers in more recent times include a receiver has been used in series with Some Novel Designs of Telephone Receivers Argyropoulus, H. Abraham (1907) and radio receiving antennae. These and a. ntended for Use in Radio Work. They Include Peukert (1909). Ort and Rieger have been number of other interesting devices are de- a Monotelephone and a Condenser or Electro- scribed in Dr. Eccle's new static Receiver. concerned with the problem since 1907, work -Hand- and reported their first experiments in book of ll'ircless Telegraphy and Te- S represent the north and south poles of "E.T.Z ", 1909. The use of the apparatus lephony. the permanent steel magnet, to which are has been chiefly simplified by abandoning A WIRELESS LEAD -IN. attached L- shaped pieces, of which the ver- a battery for charging in favor of a suit- tical parts constitute the cores D, of the able generator. A brief account of some To make this wireless lead -in for win- dows obtain a square metal rod (brass is coils C, Fig. 2. The ends of these cores improvements and experiments in this di- best) slope rection are given below. about 3% feet long. Bore a hole towards one another under the reed. half inch from each end to admit screws. The portion E' of the reed is cut away as The first condensers made by Ort and Now screw this rod on to an insulating shown to increase its flexibility. A suit- Rieger, were of rectangular shape with base as in figure. This should be longer able free period is from 800 to 1,200 per stretched paper dielectric. The edges were than the metal bar so it may be screwed to second. F is a light, conical aluminum clamped to avoid noises due to the condens- the window frame. Then cut a piece of diaphragm (not shown in Fig. 1) attached er itself. Circular leaves were afterwards spring brass about 6 inches long and bend at its center to the reed E, at a point ec- used, consisting of thin tissue paper, satu- and screw to base as shown on sash. Now centric with respect to the axis of the core rated with shellac and coated with tinfoil. screw the bar to the stationary outside D. The periphery of F is close up against The condensers were made up from these frame of the window and the spring to the the casing, or may be flexibly attached to leaves to about 0.05 -0.06 M.F. and were sash as shown in figure. When you open the casing by a ring of tissue paper,- F'. used, among other things, to prove that the window, the slider will slide along the The extent to which the reed E, can ap- the condenser as a whole vibrates as a sin- bar. Besides doing away with loose wire, . proach the core D, may be regulated as gle diaphragm, and that the amount of it also permits the window to be opened shown in Fig. 3. If the set screw is tipped sound produced depends upon the area of freely. with gold or platinum, it may be used for the plates. These paper condensers were Contributed by short- circuiting the coil when an unduly never as sensitive as the electro- magnetic FRANCIS K. FRASER. heavy current reaches the instrument, as in- telephone, and the low insulation resistance dicated in the sketch. High sensitivity is (about 500,000 ohms), was found to be claimed for this receiver. chiefly responsible. The One -tone or Monotelephone. After much experimenting, india- rubber When the diaphragm or reed of a tele- was selected as the best material for the phone receiver is designed to vibrate at leaves on account of its high insulating a definite frequency, it is said to be tuned. properties and low dielectric losses. Mica, Such a nonotelephone designed by Merca- although suitable in other ways, was aban- dier consists of a thick diaphragm, resting doned on account of these losses. The on three points, actuated by a polarized construction of a rubber sheet, condenser electro- magnet in the usual way. The in- telephone is shown in Fig. 5. On an alum- strument shown diagrammatically in Fig. 4 inum drum, a, 10 cm. in diameter, the rubber is much more sensitive than Mercadier s. leaves are stretched in the same manner as The ferrotype diaphragm is fastened be- a drum skin. They are fixed around the tween a tight wire and a fixed axle; the periphery so that no irregular vibration pitch is adjusted by a worm wheel that can take place. Each leaf is from 0.3 mm. controls the tension of the wire. The elec- to 0.5 mm. in thickness and weighs about trical parts (not shown in figure) are the 400 mg. The drum is covered by a cap, same as in ordinary instruments. e, provided with contacts, K, and K,, mak- Tuned telephones have not proved very ing connection with the plates, while a useful in connection with musical spark sig- back plate, d, is fixed at a distance from You Can Raise the Window when Fitted With This Clever Lead -In Contact Rail and Shoe nals. The note of a spark is very rich in the case as a reflector for sound from the Without Twisting, the Lead -In Rat -tail Cable. over- tones, and when a receiver is tuned inner surface of the condenser. The choice to the spark rate, the energy of the fun- of a material for the plates was settled Hongkong, China, has a wireless station damental is collected by the diaphragm, only after many comparative tests, alum- with a radius of 500 to 700 miles in daytime and that of the overtones is thrown away. inum leaf about 0.001 mm. in thickness be-. and more than 1,300 miles at night. The addition to a telephone receiver of an ing finally adopted as giving the greatest acoustic resonator has been tried by many. sensitivity. This was attached to the rub- An electric burglar alarm has been per-

These resonators usually consist of an air - ber leaves by a special process. The in- fected for the chicken coop. Lift the chick. chamber capable of adjustment to the pitch sulation resistance of complete condensers and you ring the owner's bell.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 817

By studying the drawing the action will A Rotary Receiving Tuner be clearly understood. When the pointer By Oliver M. Black is set at zero on the scale the switch inside The loose-coupler I am about to describe To the tube L Is fastened the coil I. On of the casing is off the sector, thus break- is of the variometer type. It is very the outer end of the tube L is fastened the ing the circuit between the movable plates efficient, having no dead -ends or raps, and knob B. and the secondary winding. it is unusually selective. Moreover, it is so Through the tube L runs a rod M, on The illustration given shows the inside which is fastened the coil J. On the outer of the condenser. end of this rod Al is fastened the knob A. The idea might also be used on some On the back of the case, on the inside, are of the condensers now supplied the ama- fastened two tubes N and O of the same size as the tubes L and K respectively, and they act in the same manner as tubes L and K. To the under sides of the knobs A, B and C are fastened the pointers F, E and D. The connection of the coils are as fol- lows: -The outside end of coil G goes to the aerial binding -post, while the inside end is fastened to the outside end of Coil H. The inside end of coil H goes to the ground binding -post. (See Fig. 3.) The utside end of coil I goes to one secondary binding-post while the inside end is fastened to the outside end of coil J; A Clever Scheme Whereby the Capacity of a Variable Condenser May Be Reduced to Zero, by the inside end of coil J goes to the other Opening One Side of the Circuit. Fig. 1. Front View of Rotary Type, Radio Receiv- binding -post. ng Tuner. The Relative Position of the Four secondary Windings Can Be Altered Quickly by Means of The connections cribed above should teur market, but to my knowledge there is the Centralized Knob Control. be of flexible, insulated cord with all the hardly a rotary variable condenser that soldered. possesses an absolute zero. is joints compact, light and easily portable that it The knobs of A, B and C are preferably Contributed by SAMUEL GRISCOM. just the tuner for a portable set. If made of hard rubber. Should the maker wish to from good materials, i.e., mahogany and mount all instruments in the one cabinet, A QUICK METHOD OF LAYING hard rubber or Bakelite, it adds greatly to it is a comparatively simple matter to make OUT ANGLES. the appearance of any station. the case a little longer, mounting the de- The only things required for the above The box in which the coils are mounted tector on the outside and the condensers purpose are a 12" scale and a table of is preferably of mahogany and measures on the inside. Any one carefully following Natural Tangents, such as found in most 10%" high, 12" vide and 10%" deep. The these directions will be able to construct an all engineering hand -books. front panel is of hard rubber or Bakelite. excellent instrument. Referring to Fig. 1, suppose you want Fig. 1, shows a front view of the case to lay out an angle of 20 degrees and 34 with the knobs, pointers, 180 degree scale minutes. Consult the table of natural tan- an' binding -posts. gents and find corresponding decimal Fig. 2, shows a side view, with the side fo which is .37531; now multiply by A or 5" of the case removed. Coil G, is 9" in di- V gives 1.87655 or Ws ", and draw line C, ameter and 2%" wide. It is wound closely which completes your angle of 29° 34'. for a distance of 2" with No. 24 B. & S. Since the tangent of angle 20 °, 34' is single silk covered magnet wire, starting equal to B =A from trigonometry, therefore 34" from the edge. to obtain side B it is necessary to multiply Coil H, is 8%" in diameter and 23;" wide the value of the natural tangent or .37531 -wound with a few more turns than coil G by 5. Either B or A may be known for in order to get the same amount of wire producing the angle by substituting the on both coils. Both toils should be wound value in the above simple equation. in the same direction. Coil H, is wound In fact, the base line A, can be any with No. 24 B. & S. single silk covered wire. length, so long as we use the length as our Coil I, is 8" in diameter 2%" wide, by Fig. 3. Hook -Up for Rotary "Switch- less" Tuner multiplier. wound closely for 2" of the width with Also such hand -books contain invariably No. 30 B. & S. single silk covered wire. PSALM XXIII OF THE RADIO BUG tables of square roots or the square root Coil J, is 754" in diameter and 234" wide, 1. Wireless is my hobby; I shall want no may be worked out (also by logarithms) -wound with a few more turns of wire than other. applying the usual geometrical law: coil I, in order to get the same amount of 2. It giveth me good grades in Physics; Length C = At -i- B2 wire on both coils. Coil J is wound with it leadeth me into the fields of invention. N/ No. 30 B. & S. single silk covered wire. 3. It fireth my ambition ; it leadeth me Length B = 1/ Cs - A2 Both coils I and J should be wound in the in the realms of science for knowledge's some direction as coils G and H. sake. Length A = C2 - B1 Coil G is fastened directly to the front 4. Yea, tho I walk thru the valley of the It should be noted that all such calcula- shadow of gloom, I shall fear no bad tem- tions are to be carried out in units of one per; thy coils and detectors they comfort denomination, as inches, feet, yards, or me. 5. Thou preparest pleasure before me in the presence of disappointments; thou anointest my head with fame, my "pep" runneth over. 6. Surely pleasure and profit shall fol- low me all the days of my life, and my "call" shall dwell in the ether of the uni- verse forever. Contributed by JOHN R. MARTIN. REDUCING ROTARY V.C. CAPAC- ITY TO ZERO. Here Is a Method for Computing Accurately the Those using a rotary variable condenser Height of a Radio Mast or Building, or the in shunt to the secondary winding of a Distance Across a Stream. loose coupler find that with some stations Fig. View Rotary this decreases the strength of signals. meters, etc. Never mix up inches with Modified metter No Sliders or feet. Switches Are This is due to the fact that there is always Used. some capacity in shunt even though the Contributed by JAMES McINTYRE. panel in a vertical position. Coil H is pointer is set at zero. To overcome this fastened to the brass tube K, on the other I have designed a switch which does away When erecting radio masts and spread- end of which is fastened the knob C. with the trouble without necessitating the ers, do not forget that a coat of paint will Through the tube K runs another tube L, use of an extra switch to cut out the con- help to preserve them, including the iron which will fit snugly and turn rather freely. denser. parts.

www.americanradiohistory.com 818 THE ELECTRICAL EXPERIMENTER March, 1917

RADIO CONDENSER HINTS. not require a battery for efficient operation. from "sending" to "receiving" in buzzer or When receiving long waves in wireless Moreover this detector does not require to small spark coil radio transmitting sets. telegraphy, high capacity variable condens- be adjusted; that is, it is permanent. For It is made of two S. P. D. T. baby switches ers are often necessary. the construction of this detector the fol- screwed together on a block of hard rub- As the price increases with the capacity, lowing materials will be required: ber or fiber. This block may be screwed I devised the scheme here shown diagram- o a ARTICLE No. DIMENSIONS REMARKS sub -base. Two holes are bored in each Small wide mouth bottle i About 134 x 2" Rubber stopper i To fit bottle Having 2 holes Zinc rod 1 3 x jfl Glass tube 1 6" I. z 3- 10 " I.D. Wollaston wire - jy" long Binding post 2 Wood base 1 4" x 234" x s/s Stain & Polish 5 cents worth mercury. 5 cents worth sulphuric acid. Take the glass tube and heat it in a Bunsen burner flame three inches from the end, until it is soft. Care must be taken to revolve the tube during the operation, otherwise it will bend in the middle. When the tube is soft take it out of the flame Clever Scheme for Obtaining Wide Range of it out until the heated portion Capacities with a Variable Condenser and and pull Sev- has become quite fine. Then break the tube Using Two "Baby" Knife Switches of the S. P. eral Fixed Units. D. T. Type to Construct a Small off about an inch below the point where it Antenna Switch. matically. V. C. is a variable condenser of begins to decrease in size. Now take the of the handles and the cross -bar of fiber about .0005 Mf. capacity. Fixed condens- Wollaston wire and remove its silver coat- screwed on as illustrated. A standard hard ers A, B, C and D are controlled by multi - ing for % in. by immersing it in nitric rubber pillar is used for a handle. point switch M. P. S. acid. When this is done insert the wire Contributed by In any case the capacities of these are (thin end out) into the small end of the FRANCIS R. PRAY. given in table below. tube, letting about in. protrude. Now (1) =V. C. carefully revolve the end of the tube in (2) =V. LISTENING TO YOUR OWN C.+A. the flame until the wire is sealed in with SIGNALS WHILE SENDING. (3) =V. C.+B. the end protruding. After it has cooled Amateurs (4) =V. C. -I-C., often wish to hear how their etc. break the wire flush with the end of the own signals sound but have no means of From this it is seen that any capacity tube and grind the end on a whetstone. doing from approximate zero to maximum may so, unless they go to some one's sta- tion and have a frien I operate their set be obtained. Thus if the V. C. capacity is while listen .0005 Mf. any capacity between approxi- they in. But this can be mate zero and .0025 Mf. is obtainable (con- done by means of a tele- phone. Have your friend who has a radio sidering that the unit D has a capacity of set .002 Mf.). and telephone call you up while you are by D. sending and have him hold his radio re- Contributed WALTER SHOLL. ceiver on the mouthpiece of the telephone. SILVER WIRE FOR "CAT - In this way you can hear your signals. WHISKER" CONTACTS. Of course a certain time would have to I always used a piece of copper wire for be arranged between yourself and your the cat -whisker on my galena detector and friend to do this, but you could tell him by the signals would die out and I would have wireless that you wanted to hear your to press my buzzer test to bring them in signals and he would call up on the phone again. I decided to try some sterling sil- or vice versa, if he wanted to hear himself ver wire and since then I have never had send. any more trouble. Silver wire is quite stiff Signals would have to be fairly loud so and is hard to shake out of adjustment. as to transmit over the telephone. Contributed by By this scheme one can adjust his trans- WM. MANSFIELD, JR. mitting set and also the sound of the spark A Battery -less Electrolytic Detector Comprising very easily. AN INEXPENSIVE a "Sealed Point" Electrode and a Zinc Electrode, Contributed by ARTHUR C. YOUNG. AERIAL SWITCH. Both Immersed in an Acid Solution. A 3 P. S. T. switch and two extra jaws Finish the tube by filling it with mercury, DOUBLE -WAVE AERIAL SWITCH. are necessary to construct this switch. The closing the end with sealing wax after The illustration is practically self -ex- switch and jaws should carry 25 amperes. having placed a wire in contact with the planatory. This hook -up does away with Second hand ones may be purchased for mercury. The zinc rod should be amalga- the amateur's problem of how to use a a small sum at most any electrical shop. mated. The process is as follows: Put a small and large aerial. When the aerial Mount the switch, clips up, to your switch- little mercury in a glass vessel and pour switch is thrown to the left for "receiv- board. See B in illustration. Mount the dilute sulphuric acid over it. Clean the ing," both sections of the aerial are used, two extra jaws on a porcelain or a rod and dip it into the acid until it touches (T fashion) ; when thrown to the right for hard rubber base A. and secure to the the mercury. Withdraw the rod and in- "sending," the right -hand portion only of operating table. Connect as you would vert it; the mercury should run over the the antenna is used. This latter portion any aerial switch. This makes an inex- rest of the rod; if it does not, repeat the need not be half of the aerial, but under pensive, quick -thrown aerial switch. process. To work the detector fill the glass the Radio Law should be sufficient to emit Contributed by GEORGE SWEET with sulphuric acid 1 part, water about 8 a 200 -meter wave. The switch should have. parts; the exact amount to be determined by experiment. Connect as a crystal de- //I30/0f0/S tector. / Contributed by L. MOTT -SMITH. LOW FUSION ALLOY TO MOUNT CRYSTALS. To make a suitable alloy for the mount- ing of detector crystals which will melt in hot water melt: 50% Bismuth ToreceiY/ng TO 25% Lead ser Trans 12.5% Cadmium 12.5% Tin over a Bunsen burner, being careful not to use too much heat. After all the ingredi- To Make This Aerial Change -over Switch You been and cooled How to Connect a D. P. D. T. Knife Switch so as Will Require a S. T. 3 Pole Knife Switch and Two ents have melted together to Use a Short Wave for Transmitting and a Long Extra Switch Jaws. the alloy is ready for use. Natural Wave for Receiving. Contributed by H. MENDENHALL. A BATTERY -LESS ELECTROLYTIC well spaced parts, thus adapting it to han- DETECTOR. A "BABY" AERIAL SWITCH. dle high potentials. As the title implies, this detector does This switch is useful for changing over Contributed by AN EXPERIMENTER.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 81 ThE c[o ZN5TRUQTRoo= o====coco

Staging a Scientific Entertainment By RAYMOND FRANCIS YATES NOW that the winter months are lar to the following: "Ladies and Gentle- that the Tesla coil is left out. After this here, indoor pleasures and en- men, we arc prepared this evening to offer demonstration the Tesla coil is switched in tertainments are being thought you a few interesting experiments in sci- again and allowed to spark across a gap 8 of more by wireless and elec- ence, which you can readily appreciate and inches long. The performer then grasps trical clubs, societies and other enjoy without any technical understanding. the terminal and allows the current to pass organizations, and those who wish to stage Many of the experiments to be shotton il- thru his body, the current being allowed lustrate well -known chemical, physical and to jump to some metallic object held in the ,fec ofTes/a coi/ /0/1¡0s) o/copo/ wi/h electrical laws which play a large part in hand, much to the surprise and amusement a s,cnr>t from the our every -day life, and which, but for exhi- of the audience. The next experiment is l Oser to bitions of this kind, many of you would be Transformer Sec. lee& undoubtedly totally ignorant of. A little ¡ ¡- o ,n s knowledge of some of the wonderful nat- ural laws that play such a momentous part in our every -day existence makes life seem umore interesting, and we sincerely hope that

when you leave Itere this evening you will I I carry with you a confirmed belief that the i G/ou domain of science is not merely an unin- L im Corsa- fie. 2 teresting and unproductive study, but a. gi- gantic and necessary asset to all mankind. To Show the Great Power of the Transformer a Sheet of Glass Is Punctured by Connecting fig.1 The first experiments will be with 200,000 High Voltage Terminals. e volts of electricity." Between the Igniting a Pan of Alcohol by Allowing a High in (Lights turned out and music starts.) called an electric or wireless kiss, which Frequency Spark to Jump to it From the Finger the chief performer grasps one terminal of The reference made to experimenting an entertainment often find it difficult to the gap, and, with a pin between his teeth, with 200,000 volts as the first demonstra- permits the spark to jump from this pin obtain something new and original that tion involves the use of a Tesla trans- will offer a good evening's amusement for to a pin in his assistant's mouth. This ex- former capable of giving a discharge about hibition is sure to bring applause and is a an audience. There will Ft found in this 10 inches long. A % K. W. step -up trans- article an outline for a scientific entertain- very simple one. Many other interesting former in connection with a condenser, gap experiments can be evolved, many of which ment which was recently staged by the and small Tesla coil tuned to proper reson- author with reassuring success, because it will be found in high frequency text -hooks, ance should suffice for this demonstration, such as that by Thomas S. Curtis, also that contained something unique and spectacular and, with the lights out and the music play- in the way of scientific exhibitions and by H. Transtrom. ing, a very impressive exhibition can be The next demonstrations will be in chem- which did not demand a technically trained made by lighting bulbs, drawing long audience to appreciate their truly modern istry, the first being with chlorin. The per- sparks to the body, exciting Geissler tubes former announces how chlorin is being magic. It is a devi.tion from the path of wirelessly, etc. For best results one ter- common amateur drama or comedy, aad used on the battlefields of Europe and minal of the Tesla coil should be ground- then explains that there are many more an exhibition that people of ordinary intel- ed. The audience is first shown the crash- ligence can thoroly enjoy. This entertain- humane and useful ways man has found ing 10 inch spark by the performer bring- this foul -smelling and death - ment should appeal especially to wireless ing a metallic object near one terminal of to utilize and scientific societies -.rho wish to raise dealing gas. The ladies are told that if the coil. Next, an ordinary. 8 c.p. lamp come back from the funds in order to improve their financial bulb is grasped firmly in the hand and their colored clothes situation. The description of the experi- brought into proximity with the coil. The laundry bleached snow white, that they ments employed and the method of presen- filament lights up and a peculiar blue dis- can attribute it to chlorin. Two large tation follows. charge takes place within the bulb. By widemouthed bottles of chlorin may be previous experimenting many interesting previously prepared by the methods shown demonstrations can be devised with an rs% -Pb/cssium ch/oral eMc.r electric light bulb and the author will not zs v. t fa rq on es e d oxr d enter into detail here in describing them. To show the heat of the spark used an /De/rvery tube alcohol lamp is lighted by the arrangement shown in Fig. 1. Gunpowder can be ex- ploded in the same manner. By placing in the center of the secondary of the Tesla Co/ /ecting Doue transformer two pieces of cloth, one sat- urated with ammonia and the other with hydrochloric acid, a large volume of mist will immediately arise, and by switching on the current the cloud will almost immedi- ately condense. The music is signaled to stop and the performer steps forth and announces that in the next experiment he will permit 200,000 volts to pass thru his body! The voltage is said to be 100 times that used in fg 4 electrocuting criminals at Sing Sing (or mention your State prison) Prison. To Apparatus Set Up for the Chemical Preparation Preparing Chlorin Gas by Chemical Reaction of Oxygen. of Hydrochloric Acid and Manganese Dioxid. impress the audience with the volume of the current used, and to show what utter in Fig. 3. If a piece of cheap colored A chief demonstrator and two assistants disregard it has for insulators, previous to gingham is first immersed in water and are all the persons required upon the stage. taking the current thru the body, a glass then put into a bottle of chlorin for a When the curtain rises the chief demon- plate is ruptured by it, using the arrange- moment, it will be bleached almost white. strator should make an announcement simi- ment shown in Fig. 2. It will be noticed Ink writing on paper can be entirely oblit-

www.americanradiohistory.com 82o THE ELECTRICAL EXPERIMENTER March, 1917 erated by this means, and a green leaf upon them. If the wire is connected to the appear as if the wand had absolute control from a plant can be made to lose its color 110-volt circuit it will become heated and over the disk. If a small iron (better cop- rapidly. If a little powdered arsenic or the writing in cobalt chlorid will immedi- per) frying -pan is placed over this magnet ately become visible from the effect of the it will become heated and, while not hot Mognesiurnw/re -' - heat. enough to properly fry an egg, a little but- or ribbon Electrical experiments are again reverted ter placed in with the egg will sputter and to, the first one being that telling fortunes make it appear as if the egg were being Con con/om/ng via wireless. The arrangement is shown in fried. A loop of aluminum wire will be /hermit Fig. 6, and as will be seen, it is nothing thrown into the air much higher than the Pon of more than an experiment in induction. An disk. If about three pounds of annunciator wafer assistant is used here, the chief performer wire is wound into a coil and connected to s/aeetrron requesting that the audience be perfectly a lamp, the lamp will light when brought quiet so that the wireless messages can be into the field of the magnet. This experi- properly read. The primary circuit is run ment can be made to appear still more mys- \\\\\® / to an adjoining room. Small slips of paper terious by placing the coil and lamp under fe are distributed thruout the audience and all water in a large glass jar. If a cull of a fig 5 are requested to write some word or phrase few turns of No. 4 magnet wire is made a fuse wire, enough Outfit for Demonstrating the Tremendous Heat Ipon them. The papers are collected by an and connected to cur- Produced by "Thermit" -One of the Most Power- assistant and taken to the room where the rent will be induced into the coil to blow the ful Reactions Known to Modern Science. ransmitter is installed. They are then read fuse wire. The audience will be astonished to the assistant who is sitting in the cen- and wonder where the large amount cur- into the bottle it off of antimony is sprinkled rent is really coming from. will take fire immediately, and if a piece warm turpen- The next demonstration is the concluding of paper is saturated with - Phones is upon being put one. It that of controlling apparatus by tine it will burn furiously wireless. A sensitive telegraph relay and in the bottle. coherer will be required, and are connected is told that the next ex- like concealed in do/hing The audience as shown. The oxygen and many ' Small Faoncohe coí7fn transformer, ..ap and con- periments will be with denser of the Tesla outfit are used first be made ferformers shoe for the statements of interest can transmitter. A small table containing the regarding this gas (see previous numbers "Experimental apparatus to be actuated is placed in the of this journal containing S back of the room and the devices are con- A bottle _- -- Chemistry" lessons on Oxygen). trolled from the stage. The audience is as shown in of it is previously prepared shown no is heated to Stage that wires are connected to the Fig. 4. A small iron wire table. After lighting lamps, running mo- into the bottle of Rug covering redness and then thrust j tors and ringing bells, a small cannon is ex- oxygen. It will burn like a match with a Dona* cod to odpinng room ploded and at the same instant a battery great shower of sparks. motor may be operation, hoist- common thrown into Next, the audience is told that fgt ing an American flag and the orchestra water will be changed into cherry wine. starts playing the National Anthem. A To prepare this trick, obtain a little lime A Wireless "Mind- Reading and Fortune - Telling' method hoisting flag of phenolpha- Outfit That Operates by Induction Between Two of the and exploding water and a few tablets Coils Placed on the Stage or Platform. the cannon are shown in Fig. 8. The de- thalien at the drug store. The tablets are tails of some of the experiments can well drops a put into solution and ten or fifteen ter of the stage, blind -folded and wearing be worked out by the ingenious reader, who are placed in the bottom of three table pair of 'phones. This will cause no little with will gain considerable knowledge thereby. glasses. A water pitcher is filled wonderment when the people hear their We can all do the simple stunts -but the water and about a half teacup of lime statements being read, and they will really harder ones call for more concentrated ef- water wireless. In water is placed in it. When the lime think that it is accomplisht by fort and always repay one for the trouble is poured in the glasses, it will turn to a reality it is. taken to work. them out successfully. beautiful crimson color appearing like The next experiments are magnetic in na- cherry wine. In a fourth glass, a small CONNECTING EXTENSION BELL amount of concentrated nitric acid is TO A TELEPHONE. placed, and, upon pouring the prepared Our telephone being located downstairs, water into this, it remains white. This is it was often impossible to hear it ring when not mentioned, however, and then the aud- the people were on the upper floors. To ience is told that the wine will be changed overcome this, a bell was connected from back into water. The glass containing the 'phone to the upper stories in this the acid is poured back first, and when the manner: A wire was run from a tele- rest are poured in, they will be changed to phone gong to an ordinary vibrating bell white again, due to the action of the acid. upstairs, with one or two cells for battery, The next experiment will be found to and back again to the clapper so that the be very interesting and the audience is told clapper striking the gong, to which the that they will now witness the method of wire was connected, would rapidly open blowing safes, as related by Arthur B. and close the circuit and sound the different Reeve in some of his Craig Kennedy stor- rings upstairs. A switch was also in- ies. 3,500 degrees of heat re developed in The Popular "Fried Egg" Induction Trick is serted, in the circuit, but can be dispensed this chemical reaction, which is one of the Accompiisht by Holding the Frying Pan Above with. the Table, Under which a Powerful A. C. Electro- most powerful known to modern science. Magnet Is Placed. Contributed by A. BELL GREENE. The reaction referred to is commonly known as Thermit, and in place of pre- ture and are probably the most interesting paring it, it is advisable to purchase a one and spectacular of the whole entertainment. pound can already mixed at a chemical A core for a % K.W. is made or purchased supply house. It is arranged as shown in and each leg would with about 250 turns the drawing, Fig. 5, and ignited by a small of No. 10 S.C.C. magnet wire. The coil is piece of magnesium wire. To guard against placed under a thin -topt table as shown. flying sparks, the performer should wear a The front of the table is covered to conceal pair of goggles during this display. The tin the magnet. The performer takes his place can will be entirely melted, and the charge behind the table and taking a small alum- will also fuse its way thru the sheet iron inum disk, places it on the table top directly below and fall with a loud hissing sound oveF the poles of the magnet. Using a into the pan of water beneath. small wand, he commands the disk to jump The next is an amusing experiment and into the air, which it does, as the current is may be easily prepared. A piece of white sent thru the magnet by tripping the foot - cardboard is written upon with a solution switch. The disk will act as a short-cir- of cobalt chlorid, which will be invisible. cuited coil, with the same polarity as that The cardboard is then placed in a picture of the large magnet, and instead of being frame with glass in front of it and a piece attracted, it will be repelled. The audience of sheet asbestos placed behind it. Be sure will be amazed to see this disk thrown into that the prepared surface is next to the the air without any visible force acting Raising a Miniature Flag by Radio. Spark Col glass. Now put a few tacks in the back of upon it. This can be repeated again and Fires Cannon Which Blows Weight Ott Block the frame and string some Nichrome wire again, and, by careful manipulation, it will Releasing Flag.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 821

A BALANCED RELAY BURGLAR the tapper arm slightly it will be caused a brass strip, F, running the entire length ALARM SYSTEM. to drop to one side. of the parallel part of H. Each brass AN alarm system for burglar protec- Two contacts are mounted on the wood strip, F, is connected to a binding post, K. tion consists of three main parts in a base at either side of the tapper. Adjust- It will be evident that if we insert thig balanced system. The contacts, the ing screws are provided as shown. These connector, 1, between the brass strips, IS, relay and the alarm constitute the main screws, as well as the tapper arm, should then all positive and all negative electrodes sections and we will deal with them in be silver or platinum tipt. This is not will be in parallel. By inserting the con- this order. to be adjusted until wired into the circuit. nector 2 we get 12 volts; that means all The contacts here utilized are of both The alarm signal is usually a bell or cells in series. buzzer, but where the house is wired for This second connector consists of a sim- electric lights, the sche ne of turning on ilar strip of wood, M, to which small brass every. light on the premises is a very good clips, G, are screwed; these strips are con- Conned/oar Taper one in addition to the bell. Therefore two nected as shown and the two remaining fiber Contaci r hook -ups are shown, one using the regular ones connected to two binding posts, L. " Iazrart ffooddec a- ; Its I rq1 Norm /oraus bell (Fig. 4) the other (Fig. 5) switching construction will now be described. + Water Jar on the lights so that they cannot be turned First, plane a piece of wood, A, to the off in any of the rooms, but only by re- dimensions given, 6%" long, 1%" wide and setting the alarm circuit- closer. v" thick. Next procure some brass or The circuit is wired with No. 18 cotton copper strips %" wide by 1/16" thick and covered bell wire and a resistance of 20 cut the strips, B, of which 12 are re- ohms is connected in at the far end of the quired. Drill a hole 3/16" dia. thru L', line. The relay is then adjusted so that the tapper arm lies between the two contacts. Should the circuit be closed or in fact tam- Copper owe a, pered with in any way the tapper will fall lb co persu/phot i against one or the other contact and will ì%/m/s/s/eAIi fig. 6 4MP B/Lstme coi/s Bot stay there, due to the special wiring. Thus the alarm will be given even should the l` 0l1l oircuit return instantly to its original con- iu 17 Balanced /Wäy dition. Beh The closing of the balanced relay op- //ond/e s- prnyreby erates the second pony relay, switching on De%2 /zvolt connector fig. 4 the lights ringing the alarm bell as de- or i' sired. `ro 7 rn-r rrrr rrrt_ O IIIII The batteries for this system should be .r -1 4VA*,-o l copper sulfate cells. They can be easily dalerial brau a/avg dtkoe 1311 JJ11 iJJJ uW nann made by following the sketch, Fig. 6, and should cost less than 50c. a piece; three ó 4 4 Pony rei or four being sufficient. Dry cells can be used for operating the bell. Contributed by Lighting 4p/em THOMAS W. BENSON. fan hoax using lone//e I n f //md/e z way swi%hesin A PACHYTROP FOR z each roam SERIES OR PARALLEL CONNECTION. Dei .1 2 volt connector I z rf A Pachytrop is an apparatus which en- Different Styles of Switch Blocks for Serles -par- ables us to connect the cells of a storage allel Battery Pachytrop. or primary battery in series or in parallel by simply manipulating a single handle or at a distance of %" from the bottom and by similar means. An instrument of this fix the strips B as shown to the board A, description is extremely useful when a using wood screws D. The strips are storage battery is being charged continu- spaced W apart and the board A may be ously by a gravity or copper -oxid battery. screwed to the accumulator box by wood I f the storage battery consists of six cells screws C. Bend the tips of the strips fig. S L- TO serves the E.M.F. is about 12 volts; the E.M.F. slightly outwards as this makes it easier to of the three gravity cells is only 2.7 volts, introduce the connectors. Constructional and Wring Details for a Doubly which means that we will have to con- For the connector I take a piece of wood Sure Burglar Alarm System, Utilizing a Bal- nect storage cells in parallel. anced Relay Made from a Polarized Telephone our H and plane down to 10" long, I." wide Ringer. If we should want to use the storage by %" thick. Two handles, 2" long should battery with an E.M.F. of 12 volts, e.g., then be cut on this piece while the center the open and closed- circuit types. The for- cells in series, it would be necessary to part is left parallel. A brass strip %" mer are made as shown in Fig. I. A num- change all connections and after the ex- wide by 1/16" thick is cut as shown in ber of brass tubes, i/z" inside diameter and periment, when the charging is to begin detail of F and screwed to H. 6" long, are first obtained. An insulating again, change them back again to parallel. Connect each strip to a binding post K block supporting a spring brass wire and This is where the Pachytrop comes in. and connector 1 is completed. Connector contact is mounted in one end of the tube. By simply inserting two different con- 2 is made in a similar manner, using clips The contact may consist of a 38- calibre nectors we can change the E.M.F. from G bent from the same strip as used for F cartridge shell soldered to the end of the 2 to 12 volts. The Pachytrop described and connecting them as shown. The two wire. The connections are then soldered here consists of a strip of wood, A, which remaining clips are connected to two bind- to the wire and tube. carries six brass strips, B, on each side. ing posts, L. These contacts may be put in the most The brass strips, B, on one side are con- Contributed by C. A. OLDROYD. unusual places: the hems of curtains, back nected to the positive electrodes of our corners of drawers and by drilling a hole storage cells, while the strips on the other DID YOU SAY SILVER -PLATED into the woodwork of the door they can be readily inserted. A door accidentally left WINDINGS? WELL, HERE'S HOW. ajar is thus protected, since moving it Recently I broke the "G" string on my would cause the shell to touch the tube due violin. It is a cat -gut string wound with to inertia, and the alarm would be sounded. silver- plated copper ribbon about 1.'64 inch The closed- circuit contacts may conve- wide. Upon trial I found this to be very niently take the form of two nails or screws satisfactory, as it shows a very low ohmic over which a metal short -circuiting shoe resistance. passes. Fig. 2 shows them applied to win- These strings may be secured from any dows, but shutters and doors may be pro- music supply house, one of them advertis- tected in the same way. ing a gut string wound with pure silver The relay will now receive attention. A Detail of Pachytrop Stationary Contact Block wire at 35 cents. The silver plated steel very good one can be made from an or- and Metal Jaws, Between which Rests the Re- "E" strings can be used but the steel makes dinary polarized telephone bell ringer. Ob- movable Switch Block. the resistance rather high. The fact that tain a can 4" in diameter and as deep; cut side are connected to the negative elec- the radio -currents remain on the outer sur- a lid from %" wood to fit inside. Mount trodes. The connector, 1, which gives 2 face of conductors might render them as the ringer inside the can as shown with volts, e.g., all cells in parallel, consists of a efficient as the "G" strings. tapper extending (Fig. 3). By bending piece of wood, H, on each side of which is Contributed by WM. B. SPURRIER,

www.americanradiohistory.com 82.2 THE ELECTRICAL EXPERIMENTER March, 1917 FIXING PRINTS. Testing High Voltages With Spark Gaps Ammonia forms one of the best fixing The A.I.E.E. recommend these rules for more than 0.1 per cent and the curvature, agents for prints and is to a certain extent testing high voltages with a spark gap. measured by a spherometer, should not vary superior to hyposulfite of soda used for Measurements with Spark Gaps. If prop- more than 1 per cent from that of a true this purpose. It gives clear whites and dis- er precautions are observed, spark gaps may sphere of the required diameter. solves very little of the silver. be used to advantage in checking the cali- In using the spherometer to measure the The solution consists of 1 part of am- bration of voltmeters when set up for the curvature, the distance between the points monia to 5 parts of water. The length of contact of the spherometer feet should be of fixing should not be more than 15 min- within the following limits: utes. Another advantage is that the prints TABLE 2. do not require much washing after fixing. Contributed Spherometer Specifications by THOS. W. BENSON. COMBINATION ELECTRIC LOCK. Diameter of Distance between contact points in mm. In my home I have workshop Sphere in mm. a which I Maximum i Minimum call my "laboratory" and I have a Yale 62.5 35 25 lock on the door. I had a lot of trouble 125 45 35 keeping my younger brother out when I was 250 65 45 out of town, as he found my key and made 500 100 65. one for himself. I came home often and In using Sphere Gaps constructed as found things missing or disturbed, so I above, it is assumed that the apparatus will found it necessary to put on some other be set up for use in a space comparatively kind of lock which would keep him guess- free from external dielectric fields. Care ing for a while. should be taken that conducting bodies I made a solenoid coil A, 3 inches long, forming part of the circuit, or at circuit with a fl -inch core of thin brass tubing, and potential, are not so located with reference wound it with twenty -four layers of No. 18 to the gap that their dielectric fields are enamel wire and also one with a 5/16 inch superposed on the gap; e.g., the protecting hole wound with No. 22 wire (B in Fig.). resistance should not be arranged so as to This one was 1% inches long and 1% inches present large masses or surfaces near the in diameter. gap, even at a distance of two sphere di- Boring a 3/16 inch hole in the handle of ameters. the lock at an angle of 45 degrees from the in case the sphere is grounded, the spark bottom, I placed a 3/16 inch rod in it and point of the grounded sphere should be ap- let it extend out 1 inch towards the back, proximately five diameters above the floor so that when the rod is lifted the latch or or ground. ocking bar is drawn in. There is drilled a A Standard 100,000 Volt Spherometer" for Test- TABLE 3. No. 38 hole in the extending end of this ing High Potentials by the Spark Gap Method, in Sphere Gap Spark -Over Voltages. rod and the sides are flattened by filing. Accordance with the A.1.E.E. Rules. I mounted The sparking distances between different then the large solenoid coil purposes of high- voltage tests of the insula- r.m.s. on suitable brackets on the door with its spheres for various sinusoidal volt- only tion of machinery. ages shall be assumed to be as follows: armature in the coil one -half inch. I eft room for a 3 inch connecting rod be- Ranges of Voltages. For the calibrating (At 25° C. and 760 mm. barometric pressure) purposes set forth the sphere gap shall be tween armature and rod in the knob. I used for voltages above 50 kv., and is to be Sparking Distance in Millimeters. used 5 dry cells and 2 brass screws in the preferred down to 30 kv. The needle spark door on the outside, so that by short- circuit- 62.5 mm. 125 mm. 250 mm. 500 mm. gap may, however, be used for voltages ing the screws the magnet lifted the rod and unlocked from 10 to 50 kv. l: the door. The Needle Spark Gap. The needle spark ç . ç This you will notice does not keep my ó Al IT Al L L 4T, brother or others from entering if they gap shall consist of new sewing needles, sup- Aé F gá el °l E ported axially at the ends of linear con- have the key, and as I did not want to re- ductors which are at least twice the length 8á gç om w= Sm mg 8m wa move the key barrel from the lock, in case of the gap. There must be a clear space Permanent around the gap for a radius of at least twice 10 4.2 4.2 the gap length. The sparking distances in 20 8.6 8.6 core air between No. 00 sewing needlepoints for 30 14.1 14.1 14.1 14.1 Small rû,7 sp7tig r

R. M. S. Millimeters R. M. S. Millimeters 100 56 55 52 51 52 51 Side and End Views of Magnetic Release for Aux. Kilovolts Kilovolts 120 79.7 71 64 63 63 62 Mary Locking Arm Fitted to a "Yale" Lock. 140 108 88 78 77 74 73 10 11.9 35 51 15 18.4 40 62 160 150 110 92 90 85 83 20 25.4 45 75 180 138 109 106 97 95 25 33 50 90 200 128 123 108 106 30 41 220 150 141 120 117 The above values refer to a relative hu- 240 177 160 133 130 midity of 80 per cent. Variations from this 260 210 180 148 144 humidity may involve appreciable variations 280 250 203 163 158 in the sparking distance. 300 231 177 171 The Sphere Spark Gap. The standard 320 265 194 187 sphere spark gap shall consist of two suit- 340 214 204 ably mounted metal spheres. When used as 360 234 221 specified below, the accuracy obtainable 380 255 239 should be approximately 2 per cent. 400 276 257 No extraneous body, or external of part The sphere gap 's more sensitive than the needle gap the circuit, shall be nearer the gap than to momentary rises of voltage and the voltage required twice the diameter of the spheres. By the to spark over the gap should be obtained by slowly "gap" is meant the shortest path between closing the gap under constant voltage, or by slowly raising the voltage with a fixed setting of the gap. the two spheres. Open arcs should not be permitted in proximity to the The shanks should not be greater in di- gap during its operation, as they may affect its calibra- ameter than Ys the sphere diameter. Metal tion. How a Solenoid Magnet Is Employed to Turn the Latch Spindle when the Circuit Is Closed at a collars, etc., through which the shanks ex- When the variation from sea level is not Secret Contact. tend, should be as small as practicable and great, the relative air density may be used should not, during any measurement, come as the correction factor ; when the variation he electric opener should not work, I used closer to the sphere than the maximum gap is great, or greater accuracy is desired, the the small brass angle, a detail of this idea length used in that measurement. correction factor corresponding to the rela- appearing in the figure. The sphere diameter should not vary (Continued on page 858) Contributed by ALLEN DALE.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 823

mum angular displacement, expressed in electrical Standardization Rules, American Institute of degrees (one cycle - 360 deg.) of corresponding ordinates of the voltage wave and of a wave of absolutely constant frequency equal to the average Electrical Engineers. Definitions (Revised) frequency of the alternator or circuit in question, The following definitions are intended to be for a complete cycle, .as indicated by a watt -meter. and may lie due to the variation of the prime practically descriptive, rather than scientifically Volt -Amperes or Apparent Power. The product mover. rigid, of the r.m.s. value of the voltage across a cir- The Pulsation in Prime Movers, or in the al- CURRENT, E.M.F. and POWER, cuit by the r.m.s. value of the current in the ternator connected thereto. the ratio of the (The definitions of currents given below apply circuit. This is ordinarily expressed in kv -a, difference between the maximum and minimum also, in most cases, to electromotive force, po- Power Factor. The ratio of the power to the velocities in an engine -cycle to the average tential difference, magnetic flux, etc.) volt- amperes. In the case of sinusoidal current velocity. Direct Current. A unidirectional current. As and voltage, the power factor is equal to the Capacity. The two different senses in which ordinarily used, the term designates a practically cosine of their difference in phase. this word is used sometimes leads to ambiguity. non -pulsating current. Equivalent Phase Difference. When the cur. It is therefore recommended that whenever such Pulsating Current. A current which pulsates rent and e.m.f. in a given circuit are non- sinus- ambiguity is likely to arise, the descriptive term regularly in magnitude. As ordinarily employed, oidal, it is customary, for purposes of calcula- Power capacity or current capacity be used, when the term refers to unidirectional current, tion, to take as the "equivalent" phase differ. referring to the power or current which a de- Continuous Current. A practically not[- pulsat- ence, the angle whose cosine is the power factor vice can safely carry, and that the term "Ca- ing direct current. (see above) of the circuit. There are cases, how- pacitance" be used when referring to the electro- Alternating Current. A current which alter- ever,' where this equivalent phase difference is static capacity of a device. regularly in direction. Unless distinctly misleading, since the presence of harmonics in Resistor. A device, heretofore commonly nates wave, wave, known as a resistance, used for the operation, otherwise specified the term "alternating current" the voltage current or in both, may successive half reduce the power factor without producing a cor- protection, or control of a circuit or circuits. refers to a periodic current with A coil, or same shape and area. responding displacement of the two wave forms Reactor. winding conductor, here- waves of the other; tofore commonly known as a reactance con or Oscillating Current. A periodic current whose with respect to each e.g., the case of an by the constants of the a -c. arc. In such cases, the components of the choke coil, possessing inductance, the reactance frequency is determined equivalent sine waves, the equivalent reactive of which is used for the operation, protection or circuit or circuits. factor and the equivalent reactive volt- amperes control of a circuit or circuits. Cycle. One complete set of positive and nega- current. may have no physical significance. Efficiency. The efficiency of an electrical ma- tive values of an alternating Single- Phase. A term characterizing a circuit chine or apparatus is the ratio of its useful out- Electrical Degree. The 360th part of a cycle. current to energized by a single alternating e.m.f. Such a put to its total input. Period. The time required for the circuit is usually supplied through two wires. pass through one cycle. wires, cycles or periods The currents in these two counted posi- [For the complete revised Standardization Frequency, The number of tively outwards from the source, differ in phase Rules of the A.I.h.E. address the Secretary, Mr. per second. The product of 2. by the fre- the cur- by 180 degrees or a half -cycle. F. L. Ilutchinson, 33 W. 39th St., New York.- quency is called the angular velocity of Three -Phase. A term characterizing the com- En.] rent. bination of three cir- Root -Mean -Square or Effective Value. The cuits energized by al- square root of the mean of the squares of the which cycle. ternating e.m.f.'s, TABLE I. instantaneous values for one complete It differ in phase by one- is usually abbreviated r.m.s. Unless otherwise Symbols and Abbreviatioins. an alternating third of a cycle; i.e., specified, the numerical value of 120 degrees. current refers to its r.m.s. value. The r.m.s. Symbol for Abbreviation its maxi- Quarter- Phase, also Nam: of Quantity. Unit. value of a sinusoidal wave is equal to called Two-Phase. A the Quantity. for the Unit. mum, or crest value, divided by The word r. of r.m.s., term characterizing the Electromotive force. abbreviated e.m.f. E. e volt .. "virtual" is sometimes used in place combination of two cir- Great Britain, Potential difference, abbreviated p.d V. n or E. e . .. . particularly in cuits energized by al- Voltage E, e r -Form or Wave- Shape. The shape of the or V, " .... Wave of ternating e.m.f.'s which Current /, i ampere .... curve obtained when the instantaneous values by a are against time differ in phase Q. q if coulomb, an alternating current plotted quarter of a cycle; i,e., Quantity of electricity in rectangular co-ordinates. The distance along ampere-hour complete cycle 90 degrees. Power P. p watt .... the time axis corresponding to one Sir- Phase. A term Electrostatic flux Vi of values is taken as 2 . radians, or 360 degrees...... have the characterizing the com- Electrostatic flux density D ...... Two alternating quantities are said to Electrostatic intensity when their ordinates of corre- bination of six circuits field F same wave -form by alternat. Magnetic flux 5' maxwell ** (see Phase) bear a constant ratio energized I. .... sponding phase ing e.m.f.'s, which dif- Magnetic flux densfty B. P gauss ** .. to each other. The wave -shape, as thus under- frequency fer in phase by one- gilbert per gilbert per stood, is therefore independent of the Magnetic field intensity H. centimeter cm. and of the scale to which the sixth of a cycle; i.e., 91 of the current 60 degrees. 1 or gaussf1' curve is represented. Magnetomotive force, abbreviated or Sinusoidal Current. One Polyphase. A gen- Simple Alternating eral term applied to m.m f. ,y 'gilbert* .... whose wave -shape is sinusoidal. Intensity of magnetization ) ,... current calculations are commonly any system of more .... Alternating- Susceptibility k =7 /H . .. . . based upon the assumption of sinusoidal currents than a single phase. ... This term is ordinarily Permeability b =B /H ...... and voltages. Resistance R, r ohm usually in angular meas- applied to symmetrical .... Phase. The distance, systems. Reactance X. r ... ure, of the base of any ordinate of an alternat- Impedance Z. a point on the time Plant Factor. The .... ing wave from any chosen average Conductance g mho .... axis, is called the phase of this ordinate with ratio of the load to the rated ca- Susceptance b . ... respect to this point. In the case of a sinusoidal Admittance Y, y " .... quantity, the phase at any instant pacity of the power alternating the ag- p *ohm- senti- I represented by the corresponding posi- plant, i.e., to Resistivity ì ohm -cm. may be gregate ratings of the meter tion of a line or vector revolving about a point f *mho per cen- t mho pet with such an angular velocity (vi =. 2 f ), that generators. Conductivity Y ì timeter 1 cm a convenient The Demand of an its projection at each instant upon Dielectric constant e or k ...... reference line is proportional to the value of the Installation or System Reluctance SI .... Instant. is the load which is quantity at that Capacitance (Electrostatic capacity) C - farad .... that drawn from the source Inductance Non Sinusoidal Quantities. Quantities (or coefficient of self in- henry cannot be represented by vectors of constant of supply at the re- duction) L length in a plane. The following definitions of ceiving terminals aver- Mutual Inductance (or coefficient of phase, active component, reactive component, etc., aged over a suitable mutual induction) M henry thereto. Certain and specified interval are not in general applicable Phase displacement e p degree or "equivalent" values, as defined below, may, how- of time. Demand is i radian ever, be used in many instances, for the purpose expressed in kilowatts, Frequency f cycle per second - approximate representation and calculation. kilovolt-amperes, am- radian per of Angular velocity ,v .... Crest- Factor or Peak -Factor. The ratio of the peres, or other suitable second r.m.s. value. The units. revolution crest or maximum value to the Velocity of rotation n rev. per crest factor of a sine -wave is T. The Ala.rinuim De- per second sec. mand of an Installa- convolution Form Factor. The ratio of the r.m.s. to the Number of conductors or turns. N algebraic mean ordinate taken over a halfcycle. tion or System is the or turns of wire beginning with the zero value. If the wave greatest of all the de- Temperature T, t, e degree centi- °C. passes through zero more than twice during a mands which have oc- grade single cycle, that zero shall be taken which gives curred during a given Energy, in general U or W joule, watt -hour .... the largest algebraic means for the succeeding period. It is deter. Mechanical work IV or A joule, watt -hour .... half -cycle. The form factor of a sine -wave is mined by measurement, Efficiency per cent .... 1.11. according to specifica- Length l centimeter cm. Equivalent Sine-Wave. A sine-wave which has tions, over a prescribed Mass. m gram g. the same frequency and the same r.m.s. value as time interval. Time t second sec. the actual wave. Demand Factor. The centimeter cm. Phase-Difference: Lead and Lag. When corre- ratio of the maximum Acceleration due to gravity g per second per sec. 1} sponding cyclic values of two sinusoidal alter- demand of any system f per second per sec. nating quantities of the same frequency occur at or part of a system, to Standard acceleration due to gravity ( centimeter cm. per different instants, the two quantities are said to the total connected load (at about 45 degrees latitude and )). t° {1 per second sec. differ in phase by the angle between their near- of the system, or of sea level) equals 980.6651' per second per sec. est corresponding values; e.g., the phase angle the part of system, un- between their nearest ascending zeros or between der consideration. * *An additional unit for m.m.f is the " ampere- turn. " for flux the "line, " for their nearest positive maxima. That quantity Magnetic Degree. The magnetic flux -density "maxwells per sq. tn." is said angle whose maximum value occurs first in time 360th part of the ffThe gauss is provisionally accepted the present as the name and the latter is said to lag subtended. at the axis for of both the to lead the other, unit of field intensity and flux density, on the assumption that permeability Isa behind the former. of a machine, by a pair simple numeric. Non -Inductive Load and Inductive Load. A of its field poles. One non -inductive load is a load in which the current mechanical degree is * Note. The numerical values of these quantities are ohms resistance and is in phase with the voltage across the load. An thus equal to as many mhos conductance between two opposite faces of a cm. cube of the material in inductive load is a load in which the current lags magnetic degrees as question, but the correct names are as given, not ohms and ohm sper cm. cube behind the voltage across the load. A conden- there are pairs of poles as commonly stated. sive or anti -inductive load is one in which the in the machine. [This has been the accepted standard value for many years and was formerly current leads the voltage across the load. The Variation in Al- considered to correspond accurately to 45° Latitude and sea level. Later re- Power in an Alternating- Current Circuit. The ternators or alternat- searches, however, have shown that the most reliable value for 45° and sea -level is average value of the products of the coincident ing- current circuits in slightly different; but this does not affect the standard value given above. instantaneous values of the current and voltage general, is the maxi-

www.americanradiohistory.com THE ELECTRICAL EXPERIMENTER March, 1917

' 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 a 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. Make sketches on separate sheets.

FIRST PRIZE, $3.00 SECOND PRIZE, $2.00 THIRD PRIZE, $1.00 AUTOMATIC RESISTANCE FOR A CHIME RINGER FOR THE HOME. A SIMPLE ELECTRIC BELL FOR "FORD" HEAD -LAMPS. To a clock placed in the hall an electric THE EXPERIMENTER This automatic resistance was used with chime ringer may be so connected that when The base of this bell consists of a board entire success by the author, and I thought 6" long, 3" wide and %" thick. The bell that someone else might have use for such A is 2% to 3" in diameter and is placed a wrinkle. In the illustration A is a sol- as shown. A coreless electro-magnet E, enoid about six inches long and two inches having a %" hole in it, is placed in the in diameter. A small paper tube is first center of the board 1" up. The plunger made and ends fitted on, then it is wound 1111111111111111111111111111 is made from a soft iron rod 7/32" di- full with No. 18 magnet wire. B is a ameter and 2" long with a 5/16" ball B small piece of soft iron that will fit loosely secured to it. It is held in place by a inside the tube. Some resistance wire is spring D. The binding post P, is connected then secured and wound on a tube about 11011111111111111111111 to the gong support F, with a piece of the same length as the solenoid. F is a wire. The electro- magnet is connected to small upright which holds a retractile the binding post H and the spring D; G spring C. It is all mounted on a base as is a plug of soft iron about %x % ". It shown and connected as per diagram. has three holes in it, one 1/16" in diameter, The action is thus : The current passing the middle, containing a piece of brass through the solenoid draws in the core, 3/64" holes used as vents. which carries a small slider making con- wire I; and two tact on the resistance wire. This action Contributed by ROBERT T. CRANE. varies the current supplied to the lights on the car. When the current becomes less the spring C draws the core out and de- creases the resistance and vice versa. Those Who Like Electric Novelties for the Home Contributed by H. S. OGDEN. Will Find This Chime Ringer, Actuated by the Hall Clock, a Useful and Pleasing Innovation. the clock strikes the chime rings in a room upstairs, etc. The chime ringer is very simple to make, consisting of an ordinary vibrating electric bell, with the vibrator re- moved, so as to give a single stroke. The bell is also removed and chimes substi- tuted. The clock connections are very simple and easily made. Referring to the wire /a magnet. illustration, you will note that one is grounded to the frame of the clock movement, while the other is connected to a very thin copper spring, which is Syr placed just above the striker. This enables it, when raised, to strike the gong. This To comps is a very simple but ingenious idea, and rf may be used with practical results. Contributed by CLEM O. ENOS. An Automatic Voltage Regulator for Ford ana Other Cars. Connected in the Magneto Circuit, the Solenoid Coil "A," Acts to Pull in the Iron Bar "B" as the Voltage Increases, Thus Inserting More Resistance Into the Lamp Line. The Life of the Lamps Is Thereby Greatly Lengthened.

A LOOSE -COUPLER TUNING Simple Electric Bell which Can Be Easily Made by WRINKLE. the Amateur Electrician. Silver or Platinum The question of fitting taps for coup- Contacts Will Greatly Improve It. lers, which require individual turn tuning, often causes considerable trouble. If, however, taps are taken in the usual man- LEYDEN JAR HINT. ner from each second, or each third con- Following is a little wrinkle which may volution and a special coil of one, or two be useful to the readers of THE ELECTRICAL turns, with a separate switch, is placed on EXPERIMENTER. In constructing a Leyden the end of primary tube, this difficulty is jar condenser I experienced trouble in overcome and any possible number of shellacking the, tin -foil on the inside of turns can be used. This method will the jar. Finally I placed the shellac on greatly decrease the number of taps, and the glass, then rolled up the tin -foil on a consequently the cost. stick and put it in the jar. With a little Contributed by F. C. HAMILTON. carefully manipulation the foil was spread evenly around the inner face of the jar. Electrical Contact Spring Arranged on Clock, SHOP KINKS. o that Whenever Striker Arm Descends, It Makes Then a quantity of lead shot (fine shot In drilling wrought iron or steel, al- Momentary Contact with Copper Spring. preferable) was poured into the jar, which ways use plenty of oil. Lard oil is com kept the foil prest tightly against the inonly used for such work. The oil helps fairly heavy drilling should have oiL Cop- glass. When dry the shot was removed. to carry away the heat. When drilling per is one of the toughest materials and Good adhesives for such work are thin or boring in cast iron, no oil is necessary. should receive plenty of oil. To drill large shellac, banana oil, or thin glue. Light drilling in brass requires no oil, but holes accurately, use a small drill first. Contributed by C. G. E.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 825

A MYSTIC MAGNETIC "BRASS ALARM THAT RINGS WHEN to the water makes it more conductive. To BALL. DOOR OPENS. make a fixt unit of this device a paste of Here is a brass ball that is really capable To make this simple but effective door lamp -black or powdered carbon and shellac of being attracted by a magnet. Impossi- alarm procure two pieces of wood, one may be placed between the plates and al- ble! you say? Well, then, take a glance at piece 3 "x1 "xA ", and the other piece lowed to harden. the Fig. and be convinced otherwise or, if Contributed by still skeptical, try the experiment yourself. Door frame; //Yood b/ar/r CECIL H. OSTERMEIER. A hollow brass ball filled with iron filings and a bar or horseshoe magnet will do the A SIMPLE TELEPHONE RECEIVER. trick. ig 2 A simple telephone receiver may he All students of electricity are aware that Door made by taking an old % -Ib. baking -pow- fio I der can and soldering a ring made of ordinarily a magnet will not attract a bras. r ball. The insertion of iron filings, how- heavy wire on the inside, about 1 5/16 ever, overcomes this difficulty very simply. inches from the bottom. The magnet can Ì In view of the above the performance of irqe be made from a piece of round hardened this experiment will prove a puzzle to those ÌlI Ito/es steel, 3/8 inch in diameter and 1)Q inches long. This core is then wound with about

IN 111, i Beil How to Rig Up a Simple Electric Bell Alarm on Your Door. Opening the Door Causes the Circuit to Be Closed. 4"x1 "x / ". Then obtain three pieces of sheet brass or phosphor bronze, two of them to measure 3 "xN and one 5 "x % ". Bend the longer strip to the shape shown in Fig. 2. Nail it upon piece of wood 4 "x1 "x % ", and screw this part of the alarm on the door, as shown in Fig. 1. Next take the other two contact strips and punch three holes in each of them as shown. Nail A Telephone Receiver Suitable for Experimental Did You Ever See a Magnet Attract a "Brass' Is Ball? -Then Read This Article! these upon the piece of wood 3 "x1 "x %" Telephony Readily Made from a Tm Can, an and screw it fast to door frame as shown Electromagnet and a Tin Diafram. "fellow -muckers" who are not in on the in figure. Make connections as indicated. 250 feet of No. 36 insulated copper wire, secret. Try it on them the next time you Now when the door is swung open the the ends of which are soldered to a piece have the chance. metal brush upon the door bears against the of lamp cord, passed through a hole in the Contributed by two fixt contacts on door frame, forming bottom of the can and knotted on the JOHN T. DWYER. a circuit and ringing the bell. When you inside to prevent pulling out. do to off not want the alarm ring, throw A disk of thin sheet iron should be cut A HOME -MADE DRAWER ALARM switch. to the diameter of the can, taking extreme The materials needed are scraps of Contributed by care not to bend it. The magnet WILLIAM A. NICHLERS. is then springy sheet copper or brass, some insu- placed in the bottom of the can in an up- lated 18 wire about No. for connections, CONSTRUCTING RESISTANCE right position and enough melted beeswax two dry cells, an ordinary door bell and a and resin mixture poured in to hold few small UNIT FOR SMALL MOTORS it in wood screws. AND LAMPS. place. After the wax has hardened, the From the sheet copper cut two strips /z"'' Herewith is a plan and description of a disk is slipt in and fastened tightly by a wide and 4" long and bend these to the ring of solder. shape shown in Fig. 1. simple resistance to be placed in series with battery lamps, motors, spark coils, bells, Contributed by Attach the two strips inside the furniture LLEWELLYN containing the drawer, and just back of the etc., on the 110 volt line current. ABBOTT. drawer, by the wood screws as shown in Cut two pieces of copper, zinc or tin 6x1 figure. inches and solder a piece of lamp cord to DIMMING IDEA FOR "FLIVVERS" Fords running with lights Adjust the hump H, of the spring A, in each strip, long enough to reach to the ap- connected in paratus to be operated and the switch. series are always in danger more or less. height so that when the drawer D, is closed The device described it will press against H and cause the ends Then take 2 pieces of fiber % inch square below will enable 1 the driver to make his way of A and B to separate about % ". Now by inch long (the crossbar of an old without danger. switch is excellent), place them between Take a tap from the wire connecting the when the drawer is opened even %" it will two head -lights together allow A to spring against B. thus closing the two metal plates and bend firmly to- and run it to one gether with a few stout rubber bands. point of a two -point switch (s) : the the circuit and ringing the bell until the switch. drawer is shut. When all is ready take a glass jar of blade is connected to the magneto. about one pint capacity and fill it with water. The other point is connected to a resist- Connect the two plates in series with motor or other apparatus on the 110 volt line and Be//- \ ; .Qe place the plates slowly in the water. The lamp Cord` ! JN C fuses

Be \'. y 111 e 4 4:; figt fg2 Q When the Drawer Is Pulled Out the Least Bi Dimming Idea for Auto Head -lights -a Re- the Switch Spring Closes and Rings the . sistance Coil in One Side of the Circuit Does the Be! Trick. It is well to put a switch SW in the cir- Rubber ance coil for the purpose of dimming ac- cuit and conceal it near by so that the owner BofJds cording to city regulations. The diagram can open the drawer without actuating the r shows the necessary wiring. The resist- alarm. Any number of drawers can be ance coil may consist of a few feet of No. made to ring the same bell by connecting ToMotor 20 German silver or iron wire, the proper all of the A strips to one wire and all of ; length being found by experiment. The the B strips to the other wire as shown in wire can be wound on a porcelain or wood Fig. 2. core and suitably fastened in an incon- As none of the apparatus is on the A Resistance Unit Easily Made from Two Pieces spicuous location, as under the engine bon- drawer the connections are not as likely to of Copper Separated by Wood Strips. the Whole net on the dash. be broken as vrhen they depend on flexible Device to Be Immersed in Water. Note that 12 -volt bulbs must be substi- wire. farther down you put the plates, the more tuted in place of the regular 6 -volt lamps. Contributed by BRUCE McMANAMY. current you will get. A little salt added Contributed by GEORGE McBETH.

www.americanradiohistory.com THE ELECTRICAL EXPERIMENTER March, .I917 Experimental Chemistry By Albert- W. Wilsdon Tenth Lesson CARBON. C\RBON exists in the free state in ganic liquids, and burns in the air at red the bottle. After the action has been go- nature in three modifications: [1] heat, forming Carbon Dioxid [CO,]. When ing for some time, apply a light to the end The diamond; [2] Grafite, and burned in a retort without the access of of the stricture tube. What is the result? [3] Amorphous Carbon. air, or in other words, by a process termed After the action is complete, allow the ap- The Diamond: - Destructive Distillation, the hydrocarbons, paratus to cool and examine the contents of The diamond is a crystallized form of etc., are removed. During this process the the test tube. This substance is charcoal. carbon, found in various colors, from white compounds contained in the wood are bro- -How does it differ from the original wood? ken up by the application of heat, and vola tile gases are liberated. These gases con- rr CUDes O/ IrOOd sist of volatile hydrocarbons [which are 90 compounds of carbon and hydrogen, and are combustible], pyroligneous acid, water va- One ho /e Serest robe por, carbon dioxid, etc. rubber stopper , It is made on a large scale by building up rest /age billets of wood into a conical heap and clamp covering them with earth or sand. This De/rvery rape heap is then ignited at openings near the bottom of the pile and the gases escape at 5fr/c/are small openings above. tube '\ /Rog stono Charcoal is used: - [1] For heating purposes; rubders /goe [2] As a filtering material; [3] As a polishing powder; [4] As a defactator and decolorizer of, solutions and water; [5] As an absorber of gases and aqueous Boe bo/I/e vapors; [6] As a constituent of gunpowder and fireworks; fi' 18 [7] As a purifier of water in filters, etc. Arrangement of Test Tube Containing Cubes o EXPERIMENT NO. 35- Wood for Experiment in'Destructive Distillation' Arrange the apparatus as shown by Fig 48. Fill a test tube with splinters or cubes Apparatusfor Experiment No.39,the Test Tube to colorless, through yellow, red, orange, of wood and connect the delivery tube to it Containing Copper Oxid (CuOp))ooand Powdered green, blue or brown to black. It is com- by passing the tube thru a one -hole rubber Liberated Upper Tube is den d PasUsing itlThru Lime posed of pure carbon, and can be com- stopper as shown. Set the test tube on the Water. pletely burned by fastening it with platinum ring stand, at the angle shown, and pass the in a jar of oxygen, between two poles of a other end of the delivery tube thru a two - Test the liquid in the bottle with both battery and passing a powerful electric holed rubber stopper in an 8 -ounce bottle. red and blue litmus paper. Record your re- current over it. It is the hardest substance Next take a piece of glass [about 6 or 7 sults. The decomposition of material into known, being able to scratch all other min- inches long] and first bend it as shown by simpler substances by means of heat is erals, and glass. Fig. 49 -B, and allow to cool. After it is called Destructive Distillation. The three The uses of the diamond are: cold, hold the short end of the bend in the products obtained by the destructive distil- [l] As a gem; flame of a Bunsen burner [with a fish -tail lation of wood are-a gas; a liquid; and [2] The powder is used for polishing attachment] until the glass softens. Then charcoal. others; take it from the flame, and pull it so that Boneblack [also called Animal Charcoal] : [3] Larger specimens are used in mining the glass has thinned down to a very fine This is obtained in a similar manner to for boring or drilling, and is known as the thread as shown by Fig. 49 -C. The tube charcoal, namely by the destructive distilla- Diamond Drill: thus prepared is then filed off so that the tion of bones in a closed retort. In this [4] Small fragments are set and used by finished stricture tube is similar to that case the volatile portions consisting of glaziers for cutting glass; shown by Fig. 49-D. This leaves the tube water, ammonia, etc., are driven off and the [5] They are also used by engravers for with a minute hole at the end. finely divided carbon is disseminated thru etching -points. After the apparatus is set up as shown, the porous calcium phosphat left behind. Grafite:- apply the heat of a Bunsen burner to the It has the power of absorbing gases, re- Grafite is another crystallized form of test tube containing the cubes of wood, by moving the coloring matter and alkaloids, carbon, having an iron -black to dark steel keeping the flame in constant motion over etc., from their solutions. gray color, with a metallic luster. To the It is used [1] decolorize organic touch it is a soft, greasy substance. It is 6' /lent in centre otth/s To substances and composed of carbon, either pure or with an bend for thinning especially in the refinement of sugar. [2] has also been used disinfect ul- admixture of iron, or occasionally of silica. A' stort It to alumina, and lime. Grafite is sometimes cers, etc. called Black-Lead tho there is no lead, even EXPERIMENT NO. 36- as an impurity in its composition. With a new set of apparatus the same as It is used - used in the foregoing experiment, and in [1] For the manufacture of pencils, the place of the wood fill the test tube with ani- hardness and softness of which depend up- mal bones. Heat as before. and record on the percentage of grafite used, and also your results. Test the gas at the end of the upon the pressure; stricture tube by applying a flame. What [2] As a lubricant; were the results? After the heating is com- [3] As a lining for crucibles in making plete, and the apparatus cooled, examine the steel; substance which remains in the test tube. finished of tests and [5[4] As a polish for gunpowder; Stricture tube Apply all the foregoing com- ] In the foundry to make smooth cast- pare the results with those of the foregoing ings; experiment. [6] The refractory nature permits its use rr Lampblack:- in crucibles for melting metals; Lampblack is practically pure carbon, and Showing Various Steps to be Followed in Making is [7] For the electrodes of electric fur- Glass Stricture Tube, for Use in Conducting Ex- nothing more than pure soot, such as can naces. periments Here Described. be readily seen when a kerosene lamp Amorphous Carbon :- smokes. It is a velvety, jet -black powder [A] CHARCOAL: - the whole of the tube where the wood is. very finely divided, and shows no traces of This is an impure variety of carbon pre- Never allow the flame to remain in one crystallization. It is formed by igniting pared from vegetable substances or bones position as the glass of the tube will soften various oils, which are mostly hydrocar- [Boneblack]. and finally crack bons, and collecting the unburned carbon or Wood charcoal is black, very porous, ab- Notice the color of the fumes passing smoke. sorbs gases readily, removes color from or- over the delivery tube. Also the liquid in (Continued on page 859)

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 827

What really happens is this : The phos- Trick Cigarette Papers. -Take common phorous is dissolved in the carbon di -sul- cigarette papers and dip them into a solu- fid. When poured on the paper the car- tion of saltpeter and water; be sure they bon di -sulfid evaporates, leaving the phos- are thoroly impregnated, then lay them phorous impregnated in the paper (in a out to dry. When they are dry replace finely divided form). This starts to oxidize them in their original package and hand and soon raises the temperature of some them to a friend. He will receive the sur- part of the paper to the kindling point. prise of his life Practically any kind of paper will do for Fulminating Powder. -Mix together in a this trick. Filter and newspaper both work warm mortar one part of saltpeter, two well. The main thing is not to spill it parts sulfur. Place on the edge of a fire on anything that you do not wish to burn shovel and hold over the fire. It will turn as it works 100 per cent of the time. black and explode with a loud report. Contributed by Contributed by GEORGE W. GREENE. JOHN D. COLEMAN. ELECTRIC BY S.GERNSBACK GLASS JAR CUTTER INK RECIPES. Under this heading we publish every month use- Procure two brass or iron rods, 7" long ful information in Mechanics, Electricity and Everlasting Black.- Tannic acid, 1 oz.; to by %" diameter. Flatten them out slightly Chemistry. We shall be pleased, of course, at both ends and drill holes, just large crystal gallic acid, 77 grs.; sulfate of iron, have our readers send us any recipes, formulas. 5 arabic, 100 wrinkles, new ideas etc., useful to the experi- enough to pass a battery bolt, %" from drs.; gum grs.; dilute muriatic menter, which will be duly paid for, upon pub- the ends as shown. Notice at acid, % oz.; Carbolic acid and water (acid lication, if acceptable. that one end the rods are flattened for about g" so that 10 drs.; water, 1% pints). Mix the acid EXPERIMENTER'S APHORISMS they can be almost closed. The rods are and water and dissolve the other ingredi- In the following, we wish to give to the fastened together at A with a battery bolt ents therein. This ink will not fade. Experimenter some hints as to the use of the Red Ink (Bright).- Dissolve 25 parts of and how to work them: and two nuts. A third nut serves to hold different Ingredients the wire lead. The arms should work saffron in 500 parts of warm glycerin, then (I) Always bear in mind that exact working stir carefully in 500 parts of alcohol and of a formula requires ACCURACY, CLEANLI- smoothly. Battery bolts are inserted at NESS, PATIENCE, and SKILL. B and C and á piece of German Silver 500 parts acetic acid. It is then diluted with (2) Know what you are about, before you start or other resistance wire, connected at B, 9,000 parts of water, to which a little gum to experiment. forms a loop and in turn is connected at arabic may be added. (3) "THE HISTORY OF FAILURES IS THE Gold Ink. -Fine bronze powder is mixed HISTORY OF SUCCESS" an old adage, and C. The length of wire and size remains goes with the experimenter, depending upon the with a little sulfate of potash and water; it applies well to the experimenter. the precipitate is mixed with water and a (4) Many times impure, wrong or deteriorated current available. No. 22 German Silver raw materials, spell FAILURE instead of SUC- wire will suffice for use on a step down sufficient amount of gum CESS. transformer of about 8 volts. Green Ink. -Rub 3 drs. of Prussian blue (S) A great many of the chemicals and in- and 6 drs. gamboge with 4 ozs. mucilage gredients required, cannot be obtained from drug stores; buy them at a reputable supply and a pint of water. house. Silver ink.-Silver leaf ground with a (6) BEFORE CONDEMNING A FORMULA, be little sulfate of potash is washed from the sure the fault does not lie with the manner of salt and mixed with water and a small handling it, or the purity of the ingredients. amount of gum acacia. (7) Be sure to mix the materials comprising formula in the sequence. White Ink.-Triturate together one part a certain proper honey and two parts of dry ammonia alum. (8) When starting to prepare a mixture, especially one containing liquids, ask yourself: Dry thoroly and calcine in a shallow dish "IS THE SPECIFIC GRAVITY CORRECT, AS over a fire until perfectly white. Cool, INDICATED BY A HYDROMETER? IS THE TEMPERATURE RIGHT? IS THE QUANTITY wash, rub up with sufficient gum and add OR WEIGHT RIGHT? water for use as ink. (9) Acids and water, when mixed, should be Vanishing Ink. -This ink consists of an manipulated in the proper manner, i. e., THE aqueous solution of iodide of starch. Char- ACID SHOULD BE POURED INTO THE WATER, and not vice versa as the solution is acters written with it completely vanish in liable to be forcibly ejected from the containing about four weeks. vessel and into the mixer's face. Cement (Acid Proof). -Asbestos, 2 (10) For any kind of SYSTEMATIC WORK, parts; sulfate of barium, 3 parts; silicate a floating THERMOMETER and HYDROM- ETER, as well as measuring glasses and of sodium, 2 parts. Mix thoroly and the scales. should always be provided, as GUESS- result will be a cement for all purposes WORK is EXPENSIVE, and SOMETIMES that will resist the strongest acids. FATAL. Diamonds (Imitation). -White sand, 900 (II) Put labels on ALL bottles, boxes and packages with FULL INSCRIPTION as to their An Electric Glass Tube and Jar Cutter -Current parts; red lead, 600 parts; pearl ash, 450 contents, it will avoid troubles and mistakes. Is Past from E" to 'A ", Heating Wire, when parts; niter, 300 parts; arsenic, 50 parts; Glass is Wetted at the Point where Wire En- (12) Remember that a beginner cannot expect circled It. manganese, one -half part. Melt and pour to make articles AT FIRST, which will com- into cold water. To make it harder use products. S.G pare with regular manufactured To cut a glass jar, grip the instrument less lead and if it has a yellow tint use in the right hand with the two fingers more manganese. A MAGIC FIRE FLUID. between the two arms so that they can be Contributed by The magician appears with a small bot- spread further apart if necessary. The RICHARD GAILLARD. tle of colorelss liquid in one hand and a loop of wire is placed around the jar at the few pieces of white paper in the other. point at which it is to be cut and held He proceeds to pour a little of the fluid on taut. One lead from the source of cur- HOW TO MAKE ALLOYS. the paper and then places the paper on a rent is connected at A and the other is For Clichés or Printing Plates. -Tin, 48 screen or some other metal support. held in the left hand and touched at point parts; lead, 32.5 parts; bismuth, 10.5 parts; Then he steps back; in the meantime ex- E on the wire for a few seconds. For antimony, 9 parts. plaining to the audience that this magic best results the wire should almost reach a For Candlesticks, Spoons, Vessels. -Tin, fluid, invented by the Japanese thousands red heat. After being left in place for a 80 arts; lead, 20 parts. of years ago, was used by them to torture few seconds dash a little cold water against For Imitation Silverware.-Tin, 92 parts; their prisoners, or relating any similar sto- the heated glass. A clean break should lead, 8 parts. ry to keep the audience interested. In a result. For Pieces of Jewelry; or Substitute for few minutes, usually about two, the paper Contributed by W. P. RATHERT. Silver. -Tin, 80 parts; antimony, 20 parts. will burst into flame spontaneously. The For Fusible Metal.-Bismuth, 50 parts; trick is very mystifying to any one who MISCELLANEOUS FORMULAES lead, 30 parts; tin, 20 parts does not understand the principles involved. To Poison Rats.-Mix together 2 ozs. of Brass for Medals.- Copper, 95 parts; However, it is really very simple. The carbonat of barytes with 1 oz. of lard and tin, 4 parts; zinc, 1 part. fluid is prepared by dissolving phosphorous lay it in their way. Also put a dish of Brass for Cymbals and Kettledrums. in carbon di- sulfid. Be extremely careful water near, as it causes great thirst and as Copper, 80 parts; tin, 20 parts. in handling the phosphorous, to ,cut it un- soon as they drink they die instantly. Brass for Bclls.- Copper, 77 parts; tin, der water and not to touch it with your To Preserve Dead Pets.-One lb. of dry 23 parts. hands. Also keep the carbon di -sulfid away sulfate of aluminum, one -fifth of a quart Substitute for Gold. -Copper, 94 parts; from open flames, as it is very inflammable. of water and twenty grains of arsenous antimony, 6 parts; magnesium carbonat, The odor of the commercial product is acid, well mixed. Inject this into all the part. rather disagreeable, but this may incidental- vessels of the body and you can thus pre- Contributed by ly add to the mystery of the trick. serve cats, dogs, birds, fish, etc. AGUSTIN GALVAN (Mexico).

www.americanradiohistory.com i 828 THE ELECTRICAL EXPERIMENTER March, 1917

Our Amateur Radio Station 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 publish photos of stations unaccompanied by that of the owner. Dark photos preferred to light toned ones. We pay each month $3.00 prize for the best photo. Make your description brief and use only one side of the sheet. Address the Editor, "With the Amateurs" Dept.

AMATEUR RADIO STATION were built by myself, including all brass high, made of stranded phosphor bronze CONTEST. work, studs, knobs, etc., and during the past wire. Monthly Prize, $3.00. two years I have built a number of sets, I have worked distances of over 30 miles and have This month's prize -wiener. mostly cabinets. The set shown in the July heard Key West, Colon, Darien issue by Mr. Hunt was built by yours truly and Miami. My call is 1VW. A NEW HAMPSHIRE AMATEUR also the panel he now has. Am a member GEORGES C. DELAGE. RADIO WORKER. of the Radio League of America and Greenwich, Conn. I present herewith two photos of my N.A.W.A. I am situated in the heart RADIO "LAB." OF ANDREW L. wireless station that I would like to enter of the White SHAFER. in your Amateur Radio Station contest. Mountains, hence the high aerial and have had very good success so far, my limit be- My receiving set consists of a 2,500 met- Harry Radio Who Has ing Key West, Fla. (south), and Duluth, er loose coupler, loading coil, Audiotron Built HisHiL.s Own Radio Apparatus cabinet (not shown in photograph), galena and Aerial Masts. His Set Brings Minn. (west). Have also built a few Au- in Stations from Duluth to Key dion ainplifers with good success. All my and Crystaloi detectors, variable condenser West, at Lincoln, N. H. instruments are insulated entirely with hard shunted across the secondary of the coup- rubber; not a connection touches wood. ler, fixt condensers, Brandes' 'phones and The aerial poles are built up in section:, the usual buzzer test. By means of a S.P. of doubled 2" by 4's, bolted together, and S.T. switch, I can connect the loading coil each section averages about 16 feet in into the primary circuit and it is then pos- length. I had to put the poles up alone sible to receive wave lengths of about 4,000 which was not such a lard job as it looks meters. When using the galena detector to be. Eight sets of guy wires-three wires I hear NAA very loud; NAA, NAJ, WHK, to a set -hold it perfectly steady. WCa, WOR, VBB, VBE, and a host of HARRY L. DEARBORN. other land, boat and amateur stations. Of Lincoln, N.H. course the Audiotron brings in countless others. WIRELESS SET OF GEORGES C. For transmitting I use a one -inch spark DELAGE. coil, oscillation transformer, fixt and The transmitter to the right of the quenched spark gaps (as alternates), glass change -over switch in the accompanying plate condenser immersed in castor oil and photograph consists of a % K.W. Clapp - a heavy key. The current for operating Eastham set on which I have mounted a the set is supplied by a 6 V. 60 A.H. stor- rotary gap (upper cabinet) and an oscil- age battery. lation transformer, key and motor switch I have communicated with 8 NH of St. to left of change -over switch. Marys, Ohio, several times, the distance be- The receiving (left to right) consists of ing thirty -four miles air line. I have a large, home -made loading coil, 2 galena worked with 9 WF of Fort Wayne, Ind., once, a distance of thirty -four miles also. Efficient Wireless'Station Owned 8 NH reported once, "sigs good. You by Georges C. Delage, of Green- wich, Conn. He Hears the Key sound like a Ys K.W." I attribute this good The aerial that I now have is 102 feet West, Colon and Darien Stations. work mainly to natural conditions as there high and about 250 feet long, composed of are no hills or large forests to interfere. two No. 12 copper wires, with a diagonal My aerial is of the 4 wire, inverted "L" lead -in of about 100 feet. I use this aerial type, 75 feet long, with a spacing of 3 feet, mostly for receiving. between each wire, supported by two masts - The set shown consists of two inductive 51 feet and 60 feet high, respectively. A tuners, one of which has a slider and is very good ground connection is secured used for waves up to 3,000 meters; the oth- thru a copper boiler and an iron plate 2 er has switches oit both primary and secon- feet square, each buried 6 feet in damp. dary and is used for short waves up to about earth and an iron pipe rammed into the 1,500 meters. A loading coil is used and so ground 10 feet, all being connected with connected that it can be switched into No. 4 stranded copper cable. either primary circuit. Three Murdock I hold a second grade amateur license variable condensers are used, two of which and my official call is 8 TE. I should be are of .001 mf., and a small one of .0005 detectors, detector switch, short -circuiting inf., which is connected across the 'phones. switch, Mesco variable condenser, E. I. Co., A simple galena detector is also used. On fixt 'phone condenser, Clapp -Eastham loose the wall over the tuners there is seen a coupler, Amco variable condenser, buzzer double bulb Audion detector; switches are key and 3,000 ohm Holtzer -Cabot 'phones. provided to throw the secondary on either There are two aerials, one being 250 feet the galena or Audion detector. long, two wires, 5 feet apart and 90 feet Above the Audion dectetor is a vario- high, for receiving only. The other is 85 meter that I sometimes use in place of a feet long, 3 wires, 3 feet apart, 80 feet small coil shown is con- loader, and the ,111 lllll .,,,.,,,,, 1,1,,,111,,,111111111,llll ,lll1 1 lllllll 11111111111111111111111111111111111111111 lllll lllll llll mo... nected to load up the secondary circuit 11111,,,,,i1,111111111111111111111111111111111 11111111111111,11,i,11111,1111,.1,1,,,11111.111111111,1,i11.11 when using the Audion. I use a pair of Murdock 3,000 ohm Has your station photo appeared in Andrew L. Shafer "Listening In" at His Radio 'phones and just above the 'phones is a 15 The Electrical Experimenter "? Why Receiving and Transmitting Station Located at Scott, Ohio. He Works Stations 34 Miles Away plate omnigraph that I use when in need not purchase the electrotype and have on a One -inch Spark Coil, Excited by Storage. of practise. printed with Battery. The transmitting set I now have includes some "real" stationery only a 1" coil, gap and key, and I don't very your station picture on it? All of the very glad to have any one visit my station often use it as my aerial is too big for it. s "regular radio -bugs" are doing it. or to call me by radio. ANDREW L. SHAFER. Every bit of the instruments shown with ir the exception of the 'phones and condensers Scott, Ohio.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 829

NEW INTERNATIONAL RADIO I hear Arlington (NAA) every night and KEITH McKELLIP, A RADIO STAR LIST. can also hear their time signals at noon OF THE WEST. The Berne bureau has announced the each day. I have an aerial 70 feet long and 30 feet completion of the fourth edition of the C. M. PEARSON. high. The receiving outfit includes a 3,500 Liste Alphabetique des indicatifs D'Appel Upland, Ind. (Alphabetical List of Call Letters) of the radio stations of the world. UNCLE SAM TO AID AMATEUR This publication may be procured from WIRELESS OPERATORS. the Direror International Bureau of the For the encouragement of local students Telegraph Union, Radiotelegraphic Serv- of wireless telegraphy, Ensign Philip F. ice, Berne, Switzerland, at the price of I Han,bsch of the Albany Navy recruiting franc 30 centimes per copy, plus 35 cen- station recently announced the willingness times postage. Remittances should be of the Navy Department to assist the ama- made by international postal money orders. teurs in their studies. The purpose of the department's order is said to be for the RADIO SET OF C. M. PEARSON. purpose of educating operators for use in My wireless set is a very simple one, time of war. composed of a loose coupler, loading coil, The local recruiting station will take steps galena detector, fixt condenser and a pair toward assisting the local wireless organi- of 2,000 ohm receivers. All are of my own zations. construction, except the condenser and 'phones. UKELELE MUSIC BY RADIO. The highest point on the aerial is 42 feet, following and the ground is made to a spike driven The dialogue actually took place between two naval men and was re- Keith McKellip a Youthful Radio Enthusiast of lated to ye editors by one who overheard Des Moines, Iowa. the conversation: meter loose coupler, two crystal detectors, Radio Operator (on a torpedo boat lying a pair of 2,000 ohm Brandes' 'phones, a fixt off the Carolina coast) : "Good morning, condenser and a loading coil. Captain; just picked up 'Koko Head.' Some The sending apparatus comprises a class to our set, what ?" inch coil, a nine -plate condenser, an E. I. Commanding Officer: "Go 'way with that Co., spark gap, key and a tuning helix. stuff. Next you'll be telling me you hear I good Ukeleles playing in Honolulu!" have obtained very results with the this set. I have no license call yet but ex- pect to have one before the season is over. ASKS $400,000 FOR PORTO KEITH McKELLIP. RICO RADIO. Des Moines, Iowa. Secretary Daniels has asked Congress to appropriate $400,000 for a high power wire- tion, and with a protected high power wire- C. M. Pearson Enjoys His Radio Set, Hearing Rico. less be in- Arlington (NAA) Daily. less station in Porto station communication would Mr. Daniels said the island is of "ex- sured with the fleet, with Europe and with into a tree, the pump and some other mis- treme strategic importance, in connection South America, to a greater degree than cellaneous earthed metal rods. with the fleet operations, due to its loca- by any other means." Amateur News ganizers, Thomas F. O'Brien and Sinclair Raynor journals, are kept in the Association Library The Suburban Radio Club of Washing- at the headquarters, 8 North Main St., Freeport, for the use of the members. ton, D.C. L.I., N.Y. The initiation fee is twenty -five cents, and a The Suburban Radio Club of Washington, D.C., The following were elected to hold office until fee of ten cents must be paid every week as is holding a large membership campaign by which September 11, 1917: dues. In return for the above, the members re- it hopes to enroll practically every amateur wire- President, Thomas F. O'Brien, Vice -President, ceive weekly lectures, books on Radio Telegraphy less operator in the District of Columbia and vi- Stephen Carpenter; Secretary, Mimes., Swesey and Telephony, etc., as well as the use of the cinity as a member. and Treasurer, John McCord. instruments of the Club. For application blank The club is making a big effort to dispense with The club affairs are in the hands of an execu- or further information, address Corresponding all unnecessary interference this coming spring tive committee composed of the officers and three Secretary, Albert A. Munch, 105 Excelsior St., and will try and impress every amateur with the lay members (Clifton Weindek, Stanley Terry Pittsburgh, Pa. importance of causing as little interference as and Wilbur Verity) with the President acting as possible. Chairman of the meetings. Chief Operator, Ber- The organization possesses several valuable in- tram T. Donnelly; 1st Assistant, Sinclair Raynor struments which are at the disposal of every mem- and 2nd Assistant, Ilerman Betz. San Francisco Radio Club Making ber. Every amateur in Washington should make Business meetings are held the first Friday in it a point to get in touch with the Secretary, each month. Code practice and lectures are given Rapid Progress. Chas. Longfellow, Jr., for further information. the second, third and fourth Friday in each The membership of the San Francisco Radio Address 5515 Potomac Avenue, N.W., Washing- month. The Tel- Radion Company of New York Club, the only large radio organization in that ton, D.C. The Secretary would be pleased to presented the club with a Detector. Correspond- city, has increased so rapidly that it became neces- hear from other Radio Clubs in the United States ence is solicited. Address the Secretary at the sary to vacate the former club room at 737 Shra- as to their activities. Club Wireless Station, 8 N. Main St., Freeport, der St. and occupy a new large and modern meet- L.I., N.Y. ing ball at 350 Frederick St., north -east corner The Louisville Radio Club, Louisville, of Belvedere St. K. The Experimenter's Radio Association. The new club room is amply large enough to of the Kentucky State Fair accommodate 100 persons, and without a doubt During the week The Experimenters' Radio Association of Pitts- the membership will reach the hundred mark by held at Louisville, some time ago, The Louis- burgh, Pa., completed a very successful term ville Radio Club was given space in their the end of the year. Due to the enormous amount ending August 29, 1916. The election at the of correspondence to be carried on by the secre- booth by a local newspaper and a 1 K. W. station opening of the new quarter placed the following tary, 11ír. H. R. Lee, an assistant Secretary was erected. NAA and several other high - has in office:- Ernest A. Munch, President; George been elected, Mr. E. W. Radford being the suc- powered radio stations were readily heard, while Secretary, Paul Treas- many amateur stations were "worked," much to Chartener, and Schmidt. cessful candidate. urer. At the end of the first quarter the club' Plans for the installation of a modern radio the delight and interest of the bystanders, and purchased an Electron Relay from re- especially to the young ladies who, when they bulb the station are under way and within due course of ceipts of the previous three months. THE ELEC- time the club room will be equipt with one of the began asking questions, kept those in charge TRICAL EXPERIME NTER, as well as scientific "some" busy. other best radio stations in the city. The exhibit netted the club six new members and The club is steadily growing in popularity and prospects of a number of several other members. 11111G119IfJ15YNI an average of ten new members are admitted The Louisville Radio Club has been in existence RADIO CLUBS ATTENTION! monthly. since March 1916, and now has a membership The first edition of the Year Book of the of about 45, who own and operate stations rang- San Francisco Radio Club has been sent to hun- still ing from a simple 1 -inch spark coil set, up to a dreds of addresses; available copies on hand We are always pleased to hear may be procured from Secretary, a two -cent 1 k.w. rotary gap outfit with a supersensitive the receiving set. from young Edisons and Radio stamp to be added in order to lighten the burden- The meetings are held on the 1st and 3rd some mailing charges. Thursday of each month. Certain members are Clubs. Send a write -up of your Among prominent radio operators recently ad- assigned to read papers and sometimes the meet- mitted to the club are Mr. H. R. Spradde of the ings are given a social aspect by the two club Club with photos of members and National Wireless Telephone Co.. Mr. F. L. comedians. I. P. Bohan, Club Reporter, 1410 apparatus to -day to: Editor "Ama- Busch, Radio operator at the Fort \ \'infield Scott Stock Building., Louisville, Ky. station. and several former marine operators of teur News" Section, The Electri- the Marconi Co. Radio Meetings are still held as usual, Friday eve- The Nassau League, Freeport, cal Experimenter, 233 Fulton St., nings at S P.M. Notices and announcements as L.I. New York City. well as application blanks may be secured from A short time ago a meeting of radio amateurs the Secretary. H. R. Lee. 1580 Grove St., San of Freeport and Merrick was called by the or- Francisco, Cal.

www.americanradiohistory.com 830 THE ELECTRICAL EXPERIMENTER March, 1917

OFFICIAL LIST LICENSED RADIO AMATEURS NOT TO APPEAR UNTIL NEXT ANNUAL GOVERNMENT CALL BOOK. Amateur Radio Stations Licensed by the Bureau of Navigation During the Month of July, 1916. (Continued) FIRST DISTRICT SIXTH DISTRICT- (Cont'd.) Call Power Call Power signal Owner of station. Location of station. kilowatts. signal Owner of station. Location of station. kilowatts. Anderson, Albert E 136 10V Neponset Ave., Dorchester, 6AHA Herherger, Arthur L. 1112 Maple Ave., Los Angeles, Cal. 1 Mass .5 65íJ Hickman, Roger W 441 N. Painter Ave., Whittier, Cal. .5 101' Appclin, Gustaf W 355 Adams St., Dorchester, Mass .5 6WC Kirhy, Henri F. Madrone, Cal. .5 10P Baldwin, Philip K 2 Emerald St., Medford, Mass .5 6WN IOem, Cleve H 950 Olive Ave., Coronado, Cal .5 Baskin, Israel 12 Vale St., Chelsea, Mass... .5 60Q Lemon, Melville L 815 N. Hollister Ave., Pasadena, 1QX Booth, James D 1109 Longmeadow St., Springfield, Cal 1 Mass .5 6MR Neher, Loyal A 119% E. 32d St., Los Angeles, Cal .5 Brown, Willis C Ashland, Mass .5 BALS Stuart, Burton G Mayfield, Cal. .5 1MX Calley, Elmer W Stonington, Me .5 6EQ Rohert, Jonathan L 2063 Meridian Ave., So. Pasadena, Davis, Fred R 991MI Wilmot IFO St., Portland Me .5 Cal 1 1DQ Doughty, Joseph H 67 Railroad Ave., Greenwich, Conn 6TN Snyder, Andy B 506 E. 48th St., Los Angeles, Cal .5 IAP Downing, R. Eugene 107 Grove St., Bangor, Me .5 6VZ Strawn, Harold A. 2919 Pasadena Ave., Los Angeles, 1MH Eaton, Howard W II Radcliffe Rd., Somerville, Mass .5 Cal .5 1DZ Hammond, George E Waverly St., Waterhury, Conn 1 60G Waite, Harold E Compton, Cal .5 Hiorns, Kenneth E I Hill 1EM Ave., Pawtueket, R. I .5 GALA Wells, Herhert C. Oceanside, Cal 1 Hofdick, William \Ielroee, Mass .5 AKA Whiting, Edmund W. 1047 Mignonette St., Loa Angeles, Leo F 19 1HG Jarret, Pawtucket St., Lowell, Mass .5 Cal 1 1IU Krueger, Walter II 218 W. 7th St., South Boston, Mass .5 6WY Whiting, William 132.5 Guerrero St., San Francisco, 1GS McMahon, Earl C 9 Vernal St., Everett, Mass. .5 Cal .5 1JH Martin, Ernest C 822 River St., Hyde Park, Mass .5 ((ADA Woods, Hubert 1222 Milford St., Glendale, Cal., .5 1LW Miller, Robert A 1314 Main St., Campello, Mass .5 1KM Schleehauf, William W 27 Armstrong St., Jamaica Plain, SEVENTH DISTRICT Mass .5 7AK Arndt, Norman J 1101/ S. 14th St., Tacoma, Wash .5 IDV Schwichtenherg, Wm. A 136 Nicoll St., New Haven, Conn .5 7AH Dawson, J. Oliver E. 10th and Lucille Sts., Van- 1BI Semons, Roger W. 2 Waverly Ave., Saugus, Mass .5 couver, Wash .5 1DR Smith, Percy B 1332 Main St., Bridgeport, Conn .5 HY Hicklyn, Harold H 2909 S. Warner St., Tacoma, Wash. .5 1VM Van Allen, Edward J 1 Taff Ave., Stamford, Conn. .5 7E0 O'Brien, Lester E Fairfax, Wash .5 TEE Waite, Lawrence A 333 Narragansett Ter., Riverside, 7AJ Shatto, Luveme E 426 15th St., Astoria, Ore .5 R. I .5 7DV Sheard, Harold P 207 S. 5th St., Bozeman, Mont .5 IDS Westmore, Rohert E 376 Elm St., New Haven, Conn .5 EIGHTH DISTRICT 1OL Whitmore, John W .. 64 Meadow St., Pawtueket, R. I .5 8JK Baer, Earle E 1329 Locust St., PittsburghPittsburgh, Pa .5 1TD Wilbur, Arthur E 8 E. Brookline St., Boston, Mass .5 8GD Brinker, Wm. N. 324 West Newton Ave., lEG Williams, Walter L 53 Hart St., New Britain, Conn .5 Pa. .5 SECOND DISTRICT SAJ1tI Calvert, Allen 248 Calhoun St., Battle Creek, Mich 2ASII Geoghegan, Thomas V..... Athena, N. .1 .5 .5 2ASD Gehret, Ernest G 2022 Beverly Rd., Brooklyn, N. Y .5 SQPO Carter, David G Points Aux Barques, Mich .5 2ASN Koegel, Carl J. R. F. D. No. 1, Metuchen, N. J .5 McCaig, Wm. J 1355 Ahhott Rd., Buffalo, No 1 2ASP Ruhen, Samuel 343 E. 55th St., New York, N. Y .5 U McCann, Charles S Moraine Park, Dayton, O .5 2ASK Schwartz, Adolph 1321 Franklin Ave., New York, :IV Fox, John E 1418 Oak Ave., Cincinnati, O .5 AKV Gaige, Rohert 3832 Applegate Ave., N. Y 1 J Cheviot, O .5 '2ASF Sohnle, Fred 47 Winans Ave., Newark, N. J .5 8IF Schellenbaeh, Donald 204 Elm Ave., Wyoming, O .5 2ASL Thurston, George 337 W. 14th St., New York, N. Y .5 BAFW Seiple, Rohert H I408 3d Ave., New Brighton, Pa 1 NINTH DISTRICT: TIr1Rn n18TRICT UG Blakey, Millard Auburn, Ill .5 t 3GU Bullock, George A. 015 Edgewood Ave., Trenton. N: J. .5 I. Castleherry, Jewell hl 507 Arch St., Fulton, Ky . .5 3EA Eaton, George W 1915 S. 12th St., Philadelphia. Pa .5 i SM Engler, Robert J 2712 Fremont Ave., S. Minneap- SAD Davis, Harley F. 445 W. Hanover St., Trenton, N. J 1 olis, Minn 1 3JG Graves, Edwin D Marietta, Pn .5 TE Girol, Earl C. 311 S. Baker St., Winona, Minn .5 3JW McPherson, John D., Jr 217 N. 2d St., Easton, Pa .5 UB Huston, Paul E. 2205 N. New Jersey St., Indianap- 3FP Morse, Richard F Trenton Junction, N. J 1 olis, Ind 1 3FK Smith, F. Lester 1405 Powell St., Norristown, Pa TB Koresh, George 419 50th Ave., West Allia, Mich .5 3CD Tillinghast, Carlton W 425 Wood St., Burlington, N. J .5 TT Loehe, Roy A Orland, Ill .5 3DT Williams, Alhert J., Jr 301 South Ave., Media, Pa .5 SF Mehrhols, Irvin 2133 Summerdale Ave., Chicago, I .5 ALM Meth, Charles F. 3919 N. 24th St., Omaha, Neh .5 e:XTH DISTRICT EB Oakley, Rohert N. 725 F St., Salida, Colo 1 BABA Alexander, L. R 182 Flora St., Los Angeles, Cal... .5 GQ Ristau, Harold 1937 Cornelia Ave., Chicago, Ill .5 6AAK Brinckmann, Fred E. 406 56th St., Oakland, Cal .5 NL Schattschneider, Emil G 2600 Sheridan Rd., Zion City, Ill .5 GOY Champion, Walter 714 Pine St., Oakland, Cal .5 AC Spctzman, John Powers Lake, Wise .5 6ARG Gerwing, Robert 4 1130 W. 2d St., Santa Ana, Cal .5 TS Stansbury, Clinton 1701 Summit St., Kansas City, Mol 1 Amateur Radio Stations Licensed by the Bureau of Navigation During the Month of August, 1916.

FIRST DISTRICT THIRD n78TmC-(Cont'd.) Call Power Call Power signal Owner of station. Loeation of station. kilowatts. signal Owner of station. Location of station. kilowatts. 1CN Brown, Theodore S. 51 Bigelow St., Quincy, Mass. .5 3FU Gerlach, George M 200 Maryland Ave., Cambridge, ICU Collins, George A '69 Willow St., Mansfield, Mass... .5 Md .5 1CK Florence, William E.. Jr 79 Salem St., Reading, Mass. .5 3AGM Kopp, Desmond Solomons, Md. .5 10M Haffcke, Philip M .. 17 Locust St., Danvers, Mass 1 3AX Laughman, P. Curtis 119 S. Penn St., York, Pa. 1 1BJ Hatch, Harold P West Bridgewater, Mass. .5 pRL Lowe, Ralph C 335 W. State St., Media, Pa .5 lAY Ffill, E. Roland Noank, Conn .5 3HV Mickey, Leroy 2028 S. Croskey St., Philadelphia, Inderelst, Wm Mystic, Conn .5 Pa .5 1JZ Drew, Frank E 31 Soule St., Plympton, Mass...... 5 3AIX Moyer, John A. 55 Hillside Ave., Madison, N. L .5 IAJ Kilduff, Thomas 32 Wensley St., Roxbury, Mass.... .5 3AIK Pane, Harry S. 222 S. 8th St., Lebanon, Pa .5 INK Kohl, Wm. C 75 Richardson Rd., Meeirose High- 3AHG Sprecher, S. Roy R. F. D. No. 5, Lancaster, Pa .5 lands, Mass .5 3AIZ Sutton, Berton K. Lehanon, N. J .5 1BV Lussier, Elphege A. 1024 Purchase St., New Bedford, Mass .5 FOURTH DISTRICT 1BQ Murdock, C. W. Lewis.... 185 Church St., New Haven, Conn .5 4BB Derby, Horace .. 41 W. Boulevard Drive, Kirkwood, 1JP Parkhurst, Richmond W... 458 Massachusetts Ave., Arlington, Ga. .5 Mass .5 4AV Hurlebaus, Edward H 439 Main St., Bradentown, Fla .5 1CH Penobscot Bay Wireless Co. Criehaven, Me. .5 413X Kramer, Kermit 308W.Main St.,Elizaheth City,N.C .5 1AV Riehardson, George D..... R. F. D. No. 4, Westport, Me .5 4CV Lee, Theodore A 36 N. hlayson Ave., Atlanta, Ga .5 lAB Shaw, Ronald H. 101 N. Central Ave., Wollaston, 4EH Shell, Samuel H. Semons, N. C. 1 Mass .5 4EG Trammell, George W., Jr 509 E. 1st St., Rome, Ga. .5 1CB Southwick, Harold F 103 Green St., Fall River, Mass... .5 4BE Woods, Dqn E Jackson, Ga 1BL Tripp, Douglas B 26 Ward St.4New Bedford, Mass... .5 FIFTH DISTRICT SECOND DISTRICT SED Simonds, Ernest A. 6045 Patton St., New Orleans, La. .5 2ATJ Falco, Charles 140 Sands St., Brooklyn, N. Y.... .5 5AW Stone, Frank M . 7919 Jeannette St.,New Orleans,La. .5 2ASY Greenman, Ralph D 138 Berkeley Pl., New York, N.Y. .5 5BR Vaccaro, Whoner 814 Washington Ave., Memphis, 2ASS Kaufer, Alvert, Jr 1085 Broadway, Brooklyn, N. Y.... .5 Tenn 1 2ASQ McCahe, Oliver 124 Comaga Ave., Far Rockaway, Watkins, Wm. O 203 1st Ave., Birmingham, Ala... .5 N. Y .5 SIXTH D18TRIC11 2ASY Moir, Stirling *007 Foster Ave., Brooklyn, N. Y .5 2ASD Mudgett. Guernsey 698 E. 22d St., Brooklyn, N. Y... .5 6ACA Andrews, Clarence A Ontario, Cal .6 2ASW Porter, Roland G New York, N. Y. (portable station). .5 GAGES Beekman, George H 430 Masonic Ave., San Francisco, 2ATH O 141 W. 138th St., New York, N. Y. .5 Cal .5 Ridley, Clarence Oceanside, Cal .5. 2ABG Runyon, Carman R., Jr 563 Palisade Ave., Yonkers, N. Y. 1 6AAE Bray, Harold R 2AST Sisson, Edgar J., Jr 214 Valley Rd., Montclair. N. J.... .5 6,1F Brown, Serine R. Oceanside, Cal .5 2ATL Storm, George 745 Highland Ave., Newark, N. J.. .5 Buckner, Harold E Morgan Hill, Cal .5 2P0 Talone, Frank A 1504 Federal St., Philadelphia. Pa. .5 611C Chaplin, Charles W... 1187 E. 5th Ave., Pomona, Cal... .5. 2ASX Thomas, Russell L 5 River Rd., Highland Park, N. J.. .5 6UX Coover, W. Rad 1613 19th St., Sacramento, Cal..... 1 2ASR Wihecan, George E 434 Pulaski St., Brooklyn, N. Y... .5 6ALD Dye, Leland E 8718 Compton Ave., Graham Sta- tion, Cal. 1 T I RIl DISTRICT 6VX Francisco, Wallace... 538 37th St., Oakland, Cal 1 3DS Alden, Philip M 334 S. 43d St., Philadelphia, Pa.... .5 6IZ Harrison, Irvin 1021 N. 9th St., Phoenix, Ariz .5 3AHL Apgar, S. Leslie Lehanon, N. J 5 6PA Heling, Earl E 1807 6th St., Eureka, Cal 1 Beard, Ralph W. 206 34th St.. Norfolk, ya 5 611F Heller, Bertram O 1133 W. 41st Pl., Los Angeles, CaL I 3HS Byam, Hendry S 768 Haddon Ave., Collingswood, 6.1K Killgore, Jason S. 1607 Vine St., Glendale, Cal. .5 N. J. .5 6BM McNamee, Bernard F...... 92.5 Franklin St., San Francisco,Cal. .5 (To be Continued)

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 831

ELECTRICITY AND LIFE. certainly be simplified by the use of this depth that electrical illumination was nec- (Continued front page 798) invention. The new device may be used essary. This was accomplisht by project- Some years ago the great Swedish scien- with equal advantage for projecting visu- ing powerful beams from electrical tist, Arrhenius, search- was reported to have sub- alized bulletins for public use. It is with- lights on the scenes to be filmed. The elec- jected one -half of a class of school children out doubt one of the greatest inventions to the action trical energy supplying these monstrous of high- frequency currents, in the motion picture field and will cer- arcs fed thru one hour daily for several months, at the tainly solve many du')ious problems. electric was heavy submarine end of which time there was marked cables and attached to dynamos driven by in- gasoline engines, supported on barges near crease in the average growth, weight, gen- 20,000 LEAGUES UNDER THE SEA. eral health and mental ability in the elec- the scene of this Twentieth Century Capt. trified pupils as compared with those not (Continued from page 791) Nemo's exploits. so treated. At the present time high -fre- fore, it is also fitted with a torpedo, which As an educational film, "20,000 Leagues quency currents are actually being used in is later actually discharged at one of Capt Under the Sea" probably rivals anything truck -gardens to promote the growth and Nemo's enemies. that has appeared heretofore. increase the size of vegetables for table Our second photograph illustrates the It is a great pity that Jules Verne, who use. submarine's sea drop -door open, one of the died some eight years ago, could not have The high- frequency currents, in short, sailors emerging under the water. The lived to see this wonderful picture, which act as vitality boosters-no other form of crew, when starting on its undersea jour - so well demonstrated his vast knowledge in electricity will do this. Galvanism, Fora - ney, is equipt with the necessary diving ap- all the various branches of science. dism, Static electricity are all valuable paratus, these being self- contained and em- Photos Courtesy of Universal Film Company agents in the hands of the Electro- thera- ploying no lines or peutic specialist, but they have little di- pipes with which to rect action in promoting cell vitality and supply fresh air. On growth, as do the high- frequency currents the back of the sailors when properly applied. are strapt comprest air Authorities explain the action of high - tanks and these are frequency currents in various ways, the fa- carried about without vorite theory being that the healing effect undue trouble. T h e is due solely to the liberation of heat in the divers' feet are covered tissues. It is perfectly true that in many with shoes having diseases the heat liberated in the body by heavy leaden soles so as the passage of from 400 to 2,500 milliam- to increase the body peres at a frequency of about one million weight, permitting the cycles is an important agent in promoting operator to walk on the an artificial inflammatory reaction and in- bottom of the sea. creasing circulation. The heat is, however, We see several won- only one of the secondary forces generated derful actual scenes at by the current; there are many other fac- the bottom of the ocean tors in the vitalizing effect. The thermic and one of our illus- theory will, for example, not explain the trations shows a pho- increased growth of plants produced by tograph of the crew the action of high- frequency currents of of the Nautilus walk- very high voltage and low amperage. In ing on the sea bottom medical practise often the most marked entirely free from results are obtained by the use of Tesla any encumbering con - currents of low intensity, but. of exceed- nections w h a t s o ever. ingly high potentiality. The author can One of the sailors can account for these effects only on the the- be seen holding a sea ory that these currents, when of proper turtle which he is car- frequency, are synchronóus with the nor- rying in his hand, mal rate of sympathetic nerve vibration, clearly shown in our and in this way increase the flow of the illustration. mysterious Pranic force thru which func- Considerable difficul- Illustrating the Novel Manner in which Scenes for the "20,000 Leagues tion and tissue growth are maintained. ties are encountered in Under the Sea" Movie Spectacle Were Photographed by Placing the High- frequency currents are now exten- walking on the ocean Camera and Operator (In Swimming Suit) Down in a Special Tube. sively used by the medical profession to bottom, due first to the tremendous water increase cell growth, metabolism and func- pressure and second to swift currents along FUR COAT "ELECTRICITY" tional activity. They tend to normalize various points. Many interesting under- BLOWS UP AUTO. the blood pressure and are the only agents water performances are given by Capt Electricity induced by the friction of a that are of real curative value in certain Nemo and his crew; the scenes showing act- fur coat worn by Surgeon Raymond Spear, stages of Arterio- sclerosis (hardening of ual man -eating sharks and hunting them, is U.S.N., grounded thru an automobile the arteries). They greatly augment the perhaps one of the most thrilling pictures standing on wet ground and caused a spark defensive powers of the organism, enabling ever made. There is no faking in these which exploded the gasoline, burning Sur- it to resist and overcome disease-producing pictures and in one of them can be actually geon Spear severely and destroying the ma- agencies. The prejudice against high -fre- seen how one of the sharks makes a vicious chine. The surgeon was able to leave the quency currents on the part of many phy- slash at Capt. Nemo, only to be rebuffed naval hospital here, but still is under treat- sicians may be attributed to the fact that with the butt of his rifle. Another fasci- ment at his home. they do not employ proper technique or nating scene is that showing a battle with Surgeon Spear had walked some distance that they use an apparatus which does not an octopus with Capt. Nemo, but this scene to his garage in his fur coat and rubber admit of proper variation of frequency, was obviously staged with a dummy octo- boots. The friction of the flapping of the amperage and voltage, in order to suit the pus. Another scientific feature shown, coat against his legs generated the electri- requirements of the individual case. which, by the way, was predicted by Jules city, while his boots insulated him from the In the next article the author will de- Verne, is the employment of comprest air ground and allowed his body to store it. scribe the details of construction of an guns which are quite necessary for the un- A spark did the rest. apparatus suitable for the generation of dersea hunts. high- frequency currents for therapeutic use What the audience of course does not CELEBRATING MR. EDISON'S and the technique for their application. see is how these pictures were taken. It BIRTHDAY. AN ELECTRIC "MOVIE" MACHINE involved the use of wonderful electrical The employes and associates of Mr. equipment in producing this most remark- Thomas A. Edison celebrated his seven- FOR THE HOME. able film. To begin a (Continued from page 79,5) with, special camera tieth birthday at a dinner held in the had to be employed. This was enclosed in electric storage battery building, Nest Or- The mother may catch on the film the first wide tubes fitted with powerful lenses at ange, N.J., at 6:30 p. in , Saturday. Feb- steps of the toddling baby; the boy can lower snap his mates at play; the family can have the end. Into this tube was placed ruary 10. The event was informal and their birthday motion pictures of every a regular photographic motion picture cam- entirely social, and about 1.500 persons were member, not to mention the Thanksgiving era as well as the person operating it. present. Some of Mr. Edison's personal and Christmas reunions. While many of the pictures were taken in friends and former associates were in- The adoption of this instrument to the actual sunlight (the sun shining directly vited. Mr. Edison's birthday is really on study of various subjects will be of im- thru the water and giving sufficient illumi- February II, but on account of that day measurable value, especially in geography, nation, providing the depth was not too falling on Sunday, it was decided to hold biology, chemistry and physics, which will great), most pictures were taken at such a the celebration on Saturday the tenth.

www.americanradiohistory.com 832 THE ELECTRICAL EXPERIMENTER March, 1917 EITEST PR.T E N T S

Advertising Novelty 13 equipotential cathode; 14 aux- rophone O, are transmitted to the sound waves or vibrations by caus- (No. 1,207,945; issued to John Jett iliary cathode or filament. Cathode secondary K, and auxiliary elec- ing a steel ribbon or wire to oscil- Lepper.) 14 of platinum, coated with oxids, trode I, so that the resistance be- late a diafram; the steel ribbon, tak- A unique electrical advertising at- and heated by battery 15 emits tween the latter and the cathode ing a turn about a phosphor bronze traction comprising a transparent electrons, which bombard cathode is thereby altered. This changes wheel or drum. cigar -shaped body; upon this are 13, maintained positive by battery the resistance of the discharging When the phosphor bronze wheel mounted a figure (Indian) holding 16. Cathode 13 is made therm - tube, which causes the microphone is rotated so as to render one end a cigar and a figure representing onically active also. A number of fluctuations to be transmitted to the of the steel band tight and the Satan. An electric motor within the equipotential cathodes can thus be primary F, of the telephone re- other end loose, the wheel acts as a base drives a worm wheel, which used, having successively increas- ceiver circuit and, eventually, to rotating snubbing block and pulls latter causes the Satan figure to ing electron -emitting. properties. the receiver H. the diafram in a certain direction, Each of the cathodes 13, 13a, 13b, which causes the opposite end of and 13e, receives a bombardment; the steel wire or band to slacken batteries 16, 16a, 16b and l6c main- Surgical Cleansing Apparatus to such an extent, that the turns taining each succeeding cathode (No. 1,209,846; issued to Charles on the wheel 13 slip, causing the positive with respect to the pre - Edmund Kells.) diafram to return to its normal :eding cathode. position; after which the operation is again repeated. Improved Primary Cell (No. 1,201,709: issued to Charles Ultra -Violet Generator Féry. ) Ray (No. 1,207,347; issued to Joseph Von Kowalski-Wierusz.)

bend forward, the spear descending and the lamp atop it lighting up, as well as the lamps within the trans- parent base. The mechanism also causes the Indian to place the small In this electrical surgical cleans- cigar in proximity to his mouth. ing and medicating apparatus, an The electric current may be sup- electric motor drives a vacuum plied from battery or lighting cir- pump, the motor being operated at cuit. The name of dealer can be certain periodical, definite intervals. placed on side of transparent base, An electric heater U, is placed in being thus periodically illuminated. the tube thru which the medicating or relief vapors pass; T, being a filter; O, the catch receptacle for Electrical Connector pus or other fluids brought from (No. 1,209,604; issued to Hosea F. the wound, and Q is the wash jar. Maxim.) V is the ether jar and FF, the tips r. An extremely simple and cheaply to be placed in the wound. manufactured form of electrical MI connector, suitable for attachment -NEE to dry cells and other electrical ap- High Frequency Radio Circuit paratus. / :N1 (No. 1,211,863; issued to David G. SG_ `7SU/O1%O/7. v Doc McCaw.) This arrangement is adapted to Over the zinc is placed a sheet of radio -telegraphy and radio -telephony. insulation such as felt, or hard A larger condenser, having about rubber, etc. On this insulation fifteen times the capacity of the B, rests the carbon element as shown. one across the secondary, is con- By thus keeping the zinc at the HfCHHHHHHf bottom of the jar the ammonium A' gas can be liberated freely . and A source of alternating current without encountering the chlorid of supplies a step -up transformer, the zinc, with which it combines in the secondary circuit of the step -up ordinary cell of this type, to form resonance transformer containing which mitigate against the Cr the special arcs SG, and condensa. crystals tion It combines, in its design, extreme efficiency of the battery. battery CB, of the proper size. simplicity, being formed from a sin- The cell rapidly depolarizes due gle piece of springy wire, which re- to the considerable electric currents quires no other operations but that which are generated between the Apparatus for Submarine Signaling of bending. top and the bottom of the carbon (No. 1,207,388; issued to Reginald The connector may be soldered electrode. nected in series with the spark gaps A. Fessenden.) to dry cell electrodes and the and the primary of an air -core conductor is secured therein by Relay for Undulatory Current transformer. pressing down on the extending fin- (No. 1,212,163; issued to Eric This method consists in electric- ger, A. Magnus Campbell Tigerstedt.) ally energizing an oscillatory circuit, A number of novel modifications An improved relay for undulatory charging the opposite poles of the in the design of this connector are currents which may be actuated by condenser F, by conduction, simul- given in the patent. The connect- a microphone O, and the effect taneously charging the opposite poles or is to be made of some springy noted in a telephone receiver H, of large condenser G, by conduc- wire, such as phosphor bronze, connected thru an induction coil. tion and induction, discharging said brass or steel. FG. condenser G, across the multiple spark H and controlling such con. Thermionic Amplifier denser discharge at the gap. No. 1,210.678; issued to Alexander McLean Nicolson.) Apparatus for Producing Vibratory Motion (No. 1,207,387; issued to Reginald A. Fessenden.) JiOIÔ/n FM. Z.

The relay comprises a soft iron Jr b1/C/O. Energy from an alternating cur- cyl nder, containing an evacuated rent dynamo 15 passes into an elec., chamber A. Therein reposes a tro- magnetic sound producing mech- cathode B, in the form of a helic- anism (vibrator) 12, Fig. 2. ally wound wire, supplied with bat- A key 16, may break up the pow- become heated. erful sounds produced by 12, tery current so as to ship A helical anode is placed over mounted on the steel hull of a the perforated grate -shaped auxil- so as to radiate telegraphic dots iary electrode, I. and dashes. The sound waves By this design, the ionizing rays, striking the hull of the vessel from owing to their radial movements, a distant station may be interpreted will be the least affected by exter- thru the same mechanism 12, or nal magnetic and electrical influ- thru a vibrating reed and micro- ences. phone, 20 -35. pri- A microphone and source of cur- The current variations in the excite In the figure, 10 represents a mary winding N, graduated by mic- A method of producing powerful rent may be used to oscil- highly evacuated vessel; 11 an lator 12, when sending telephone anode; 12 an input electrode; COPIES OF ANY OF THE ABOVE PATENTS SUPPLIED AT 1Oc. EACH speech thru water.

www.americanradiohistory.com 1Vlarch, 1917 THE ELECTRICAL EXPERIMENTER 833 Phoney Patents Under this heading are publisht electrical or mechanical ideas which then you haven't a smell of the Patent yet. After they have allowed our clever inventors, for reasons best known to themselves, have as yet the Patent, you must pay another $20.00 as a final fee. That's $40.00 I I not patented. We furthermore call attention to our celebrated Phoney WE PAY YOU $3.00 and grant you a Phoney Patent in the bargain, Patent Oftizz for the relief of all suffering daffy inventors in this coun- so you save $43.00 II When sending in your Phoney Patent application, try as well as for the entire universe. be sure that it is as daffy as a lovesick bat. The daffier, the bet- We are revolutionizing the Patent business and OFFER YOU THREE ter. Simple sketches and a short description will help our staff of Phoney DOLI.ARS ($3.00) FOR THE BEST PATENT. If you take ur Phoney Patent examiners to issue a Phoney Patent on your invention in a Patent to Washington, they charge you $20.00 for the Initial fee and jiffy. PHONEY PATENT OFFIZZ S. M. ARTALEK of KOKOBUST, O. E.M.F. AUTO PARASITE N0. s.o.s.y Spessification of Patent Bettors Patent Magnified TO HUME IT RIGHT CONSERVES: - cars -not only will work at no cost to its mentioned electromagnet C is energized Let it be known to all in and out habi- owner, but it will actually charge his stor- most powerfully and simultaneously shoots tants of the Universe and Uniprose, as age battery free of charge as well. out on the now extended aforementioned well as to all subjects of possessions and Referring to my drawing A is a dynamo X: :X: :X. Inasmuch as most car bod- territories, not admitted to Planetdom, that drove by the hindmost axle of the tlivver. ies are of sheet tin, the electromagnet will I, S. M. Artalek of the City of Kokobust As soon as the hindmost wheels rotate, experience a strong affinity for the car in the State of Complete Ossification, have the dynamo by virtue of its inherited pow- ahead and consequently will hang on with conceived, devised, invented and finally ers begins to charge without charge the bulldog tenacity, incidentally pulling along thunk out an exceedingly efficient as well storage battery B. From this latter afore- the flivver, owner, all aforementioned as profissient means of Flivver- propul- mentioned and thusly described battery above, at least as long until t'.e wealthy sion, which to the best of my knowledge B, two electric conductor insulated wires guy ahead gets wise. In that case a new and widespread researches has not appeared lead to a double electromagnet C of gen- victim must be secured. before in print anywhere in the Universe. erous and stoutish proportions as will be WHAT I CLAIM IS: Inasmuch as gasoline prices have been observed and seen by looking at the afore- 1° A gasless, costless, juiceless flivver rising skyward with such alarming regu- mentioned above previously pointed out attachment.

I Have Devised a Very Simple Electro-magnetic Auto Propulsion Apparatus, which can be Installed at Low Cost on Any Flivvet Once Installed, This Device -the `Auto- parasite' -Not Only Will Work At No Cost to Its Owner, but Will Actually Charge His Storage Battery Free of Charge." larity of late, it has become a manifest im- drawing forming part of this patent spess- 2° An autoparasitic attachment prying possibility for ordinary cattle to run about fication. upon the body of rich men's cars. in Runabouts or Runaflivvers. Altho en- Now then, the electromagnet C afore- 3° An automatic gratis- working auto - terprising garages are now giving away a mentioned above and described thereunder puller for the masses. completely equipt flivver with every five - is mounted at the bow- tttost end of a mov- In memoriam whereof, I have thus here - gallon can of gasolene, the owners have no able X :X :X :X :X as best seen and visu- before imprest in hard wax, seal in hand, further use for the car, after the original alized as well as observed in aforemen- my pussyfooted phizt this 19th day of our supply of gas gives out, as a second mort- tioned described drawing. Ford, 1917, Vs of 12 O'Clock Moon, with gage on the house and cow will not bring At the stern-1 ost end at the starboard 63° humidity on the 78 meridian due East. sufficient cush to buy enough gas to prime side of the movable X :X :X :X :X also S. M. ARTALEK, a spark plug. Realizing this lamenting aforementioned and duly described, a lever By His Attorney. state of affairs, I have devised a very sim- arrangement D with a handle is organized, JAMES McLAUGIILIN MONO. ple apparatus which can be installed at low planted and otherwise attached to suit the Fair Haven, N.J. cost on any flivver, completely and success- erstwhile fancy of aforementioned flivver lt'ITNESSES fully taking the place of gasoline. Once owner described and pointed out above. C. Laret installed, this device -which I term Auto - By moving aforementioned lever D for- Al. Kohol, Parasite, because it lives on wealthy men's ward at the critical moment, the afore- W. H. Yskey.

www.americanradiohistory.com 834 THE k:LLC fRICAL EXPERIMENTER Itilarch, 1917 QUESTIONt!1 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 will 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.

RESISTANCE OF RHEOSTAT. BELL CIRCUIT. However, this was reduced to a simpler (713.) I. Simpson, Ottawa, in- one: (712 -A.) F. Eilman, St. Louis, Mo., Canada, asks: quires: Br Rs Q. 1. What precaution should be taken Q. 1. How is the resistance of a rheostat Where: varied? with a bell when continuously operated? B= attenuation constant for the cable. A. 1. The contacts should be cleaned reg- f frequency. A. 1. The conductors are generally all in ularly and also adjusted as required. = series and connections are made at various Can you give me a C= capacity. upon a Q. 2. wiring diagram R= resistance. points with contact buttons, which a 4 bell and 4 drop annunciator a moving arm sweeps, so as to include more of for It was Pupin who formulated the different resistance. Sometimes fire alarm? 'values of B. We would especially refer or less of the the A. 2. The diagram herewith gives the resistance is reduced while the carrying ca- proper connections. you to THE ELECTRICAL EXPERIMENTER for pacity is increased by putting more or less August, 1916, page 274 -"Question Box." Q. 3. What is the appearance of an arc Q. 2. In what unit is leakance exprest? resistance units in multiple, as when a bank when observed thru a smoked glass? of incandescent is A. 2. This term has not as yet been em- lamps used for regulat- A. 3. The current (or rather the incan- ing a current. Combinations of the two are pirically nomenclatured, but it is exprest as descent carbon particles) is plainly seen the reciprocal of insulation which made occasionally, the highest resistance passing from the positive to the negative resistance, being given by connecting the units in series carbon. is in megohms and is called mohoms. It is while the resistance is reduced by cutting very small in aerial telephonic lines and out one section after another, the resistance quite large in underground cables. being still further reduced by putting units in multiple. HIGH FREQUENCY RESISTANCE. Q. 2. What is the difference between a (715.) John Olsen, Hempstead, L.I., in- pole -changer and a pole -changing transmit- quires: ter? Q. 1. Is the direct current resistance of A. 2. The construction of a pole- changer a conductor equal to that offered by the is such that the circuit is momentarily bro- same conductor, when said wire is excited ken at each reversal, whereas in the pole - by means of an oscillatory high frequency changing transmitter, continuity of the cir- current? cuit is preserved. A. 1. The high frequency resistance of a Q. 3. What is accomplisht by the use of conductor, when it is excited, is not the relays on telegraph lines? same as its D.C. resistance, but is several A. 3. They reduce considerably the bat- times as great as its D.C. resistance. The tery current' required and the size of con- following expression is used for calculat- ductors used. The relays operate on a ing the high frequency conductor size: small fraction of an ampere while tele- The high frequency resistance of the con- graph sounders require a fairly large cur- ductor is: rent in amperes. The relay for main line 12,=R-157 work is usually of 150 ohms resistance; Where : short line relays have 20 ohms resistance, R1 =high frequency resistance of the and specially wound sounders of 20 ohms conductor. resistance are sometimes used. Relays are d= diameter of conductor in centi- of more delicate construction and conse- meters. quently more sensitive than sounders, which R= direct current resistance of con- latter utilize a heavy sounding bar. The ductor. sound given off by a relay armature is Wiring Diagram for Four Room Bells and Fou Drop Annunciator, so that Clerk Can Ring N= frequency of the oscillatory cur- often intensified by fitting a resonator or Guests' Bells In Case of Fire. rent passing thru the wire. diafram horn to it, as described some time The formula below applies only to solid, in ago this journal. PUPINIZATION. nearly straight or slightly curved, circular - (714.) W. Wilson, Pittsburgh, Pa., asks: sectioned copper wires. X -RAY QUERIES. Q. 1. \Vhat is meant by Pupinization? Where: A. 1. The word is derived from Profes- (712.) Paul Higgins, Charleston, S.C., sor M. I. Pupin, of Columbia University, d .4774v=N wishes to know: who introduced the first successful method Q. 1. How are X -rays produced? of loading telephone cables and aerial lines. d =dia. wire in cms. for high frequency A. 1. If an electrical discharge be passed The inductance coils are built in ring form current. thru a vacuum tube. X -rays are produced and each has a definite value, depending up- P= resistivity of the conductor ( =1600 whenever the cathodic stream is arrested on the characteristics of the line and its for copper). by the walls of the tube or metallic objects location. N= frequency. therein. When working with telephone cables, cer- Q. 2. Does the Cohen circuit of capacity Q. 2. What is a focus tube and for what tain obstacles are to be overcome, such as tuning prove more efficient than the straight kind of work is it most applicable? inductance, capacity. resistance and leak- inductance tuning? A. 2. A focus tube is one in which a ance. Capacity troubles telephone engineers A. 2. The capacity tuning of the Cohen concave cathode electrode causes the stream most, and this was compensated for by circuit is more selective than the straight of electrons to be focused upon a flat tar- adding inductance to the line. Special care inductance system, but it has been found get or anode. They are generally used for is exercised in designing inductance (load- that it is not particularly efficient when it obtaining a rapid radiograph of finite, con- ing) coils, and Professor Pupin was the is used on wave lengths above 2,500 meters, centrated area. one who developed mathematical proofs and on long distance work. Q. 3. What is the composition of chemi- and design data of loaded telephone cables. Q. 3. Does it effect any improvement to cals employed in the manufacture of fluo- The attenuation of cables is very im- employ several arcs for radiophone work rescent screens? portant; it is wise to keep this as low as and are they better than a single arc? A. 3. They are generally composed of possible. The American Telephone and A. 3. Several arcs are better than a single platinum-barium -cyanid, while the cheaper Telegraph Company consider 3.66 for the arc, as considerably more current is gen- variety are made with phosphorescent cal- attenuation constant of a cable. This con- erated with a multiple arc system. The cium sulfid. stant is obtained from a large expression. (Continued on page 836)

www.americanradiohistory.com March, Igl7 THE ELECTRICAL EXPERIMENTER `,35 READ THESE LETTERS HERE IT IS AND HERE IS WHAT IT DOES "Improve It and It Is Useless" No tuning capacities, and no switches in the Audion Circuits. No end losses, and no short circuited turns.

Amplifications up to l 00 times. Selectivity as great comparatively as the "PARAGON" RA -6 Amplifying Short Wave Receiver. amplification. Range 180 -580 meters. Price $35.00. "It Has Soloed the Transcontinental Relay Problem" All amplifications obtained without change of spark tone. Covered by a 2 -year satisfaction -or -your- money -back guarantee. FURTHERMORE, we guarantee the RA -6 to so far excel other short -wave re- ceivers, that there is no comparison. A PRODUCT MAY BE JUDGED BY ITS USERS!

"The results obtained have been almost marvelous." " 'The Set' received several days ago. I want to say it is a peach. and (2LK) J. O. Smith. Valley Stream, N. Y. even surpassed my expectations. It is a wonder for selectivity. and all signals very much louder. Have heard stations that I had never heard "In a word. I think it is the greatest short wave tuner I ever saw." before, and (8JZ) Rev. A. J. Manning, Cleveland. O. worked IVN at noon. You may remember that Hartford has always been closed to us around here." "I take this time to congratulate you on the design of the perfect short- (2AGJ) John K. Hewitt. Jr., Albany, N. Y. wave receiver. I have never seen anything in its class before." (2FS) Howard L. Stanley, Babylon. N. Y. "Never dreamed that the possibilities of this type of apparatus were so great until I installed instrument. "I am delighted with the results." Wm. H. Allison. Worcester. (2AFT) Folger Oudin, Schenectady. N. Y. Mass. "The finest set for amateurs I have ever tried out. Just as you represented "I like the RA-6 very much." it to me. Have been able to hear some 5s, some 4s, and any number of I, 2, (IZM) Hiram Percy Maxim. Hartford. Conn. 3, 8, and 9 stations every night, no matter what the air conditions." "The results obtained with it have surprised me very much. Using it (2ZP) John W. Hubbard, Port Chester, N. Y. I worked 2AGJ at Albany for about an hour. and not once did he fade out so I could not get him back. At times I could hear him several feet from the "Have used the RA-6 for about a week with such marked results, that 'fones. Other stations hitherto just readable come in very loud." thought a word of appreciation at this time might be of interest to you." (91K) R. H. G. Mathews, Chicago, Ill. (21M) L. Spangenberg, Lakeview. N. J. "Results entirely satisfactory. Atmospheric conditions not at all good. "The increase in intensity of signals received is almost beyond belief, and Notwithstanding this. however, with two sets of 'tones in series, we could hear I have astonished many of my friends, as well as myself. The set is the most and copy many long distance stations including 5DU, 5AM, 8AEZ and 9BY selective I have ever handled, and when familiar with it wonders may be as well as several others we did not mark down." performed." John C. Cooper, Jr., Jacksonville. Fla. (2ABG) C. R. Runyon, Jr., Yonkers, N. Y. PARAGON INSTRUMENTS HAVE SET NEW STANDARDS Send 6c. for our 232 pp. Catalog

Send stamp today for Bulletin Our No. 7 Catalog shows several hundred different O. It will interest you. It de- parts and also sets of ma- Contains complete de- terials for building your scription and prices of own apparatus. We do scribes a variety of correctly all the difficult work in our all the latest Wireless factory and give you the and Electrical Goods. benefit of machinery and designed apparatus - appa- equipment.

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www.americanradiohistory.com 836 THE ELECTRICAL EXFERIMENTER March, 1917

QUESTION BOX. THUNDERSTORMS OF THE (Continued ¡roui page 834) UNITED STATES. only difficulty encountered in operating a A thoro study of the distribution of Send 10c for multiple arc is in properly adjusting them thunderstorms has been made by Mr. W. for an oscillating condition. H. Alexander with the aid of the officials in charge of more than one hundred of the Our Manual of MAGNETIC ORE SEPARATOR. regular weather bureau stations. Follow- (716.) P. Pierpont, Hoboken, N.J., wants ing this, Professor R. DeC. Ward has fit- to know: tingly brought out the significance of the Tel- Q. 1. How does Edison concentrate iron thunderstorm as a climatic phenomenon, Wireless ore magnetically? says Science. A. 1. The ore treated is a magnetic ore of Thunderstorms are produced (1) by the W9 iron held in about three times its weight excessive heating of the lower air; (2) by egraphy of easily crushed rock. This is crushed be- the over- and under -running of winds of tween rollers and then allowed to fall in different temperatures, which in some way You Get Your Money Back a thin sheet in front of a series of mag- cause moist air masses to rise rapidly; and on an Order of $1.00 nets, which deflect the iron particles, but (3) by the cooling of the upper air. These allow the iron magnetic rock to fall ver- causes usually are not individually respons- tically. A thin, knife -edged partition board It contains 180 pages and tells how to ible for any thunderstorm ; but act in con- separates the two falling streams. The at- junction. Excessive heating of the lower erect and maintain wireless telegraph tracted particles are dried and ground and diagrams. air occurs in summer and most favorably stations. Shows a number of then separated again from the rock mate- on plains, plateaus and intermont basins. Has the Morse and Continental Tele- rial, then treated chemically and again sep- Thus in the United States the maximum graph Codes. Illustrates the best in- arated. number of thunderstorms is to be expected struments to use: tells what they are Q. 2. How is the attraction of unlike in the Mississippi Valley, and in the west- for and how to use them. Has many poles and the repulsion of like poles ex- ern mountain and plateau region. Further- new diagrams and other valuable infor- plained? more, most come in summer: in 126 of 139 mation not A. 2. There is no complete explanation . stations considered the month with most contained in agreed upon, altho all the actions can be thunderstorms is June, July or August. Cy- any other referred to simple laws. There is tension clonic activity in a region subject to marked Do along the lines of force and a pressure at temperature changes is usually responsible book. right angles to them. for the production of thunderstorms by not wait. over-running and under-running winds. Send your SELENIUM CELLS. This leads to the winter and spring thunder- request now. (717.) Frank Ileeney, Portland, Ore., storms; particularly in the southern Mis- Get the best asks: sissippi Valley where the lower air is warm- 10c value Q. 1. How are selenium cells made? est and dampest. The cooling of the upper you will ever A. 1. The subject on the construction of air while the lower remains relatively warm buy. selenium cells is quite extensive, and lim- is characteristic of a marine location. With ited space forbids us to publish here com- the aid of cyclones, thunderstorms pro- plete details on their construction. We re- duced in this way are to be expected in fer you to the November 1915 and Septem- winter and at night. The Pacific coast Send for Our New ber 1916 issues of THE ELECTRICAL Ex- region thus tends to have its thunderstorms, I'ERIMENTER in which you will find a com- few at most, in winter. plete exposition of the construction of sel- For illustration, the accompanying table Catalog W28 enium cells. If you have not these copies shows the monthly percentage frequencies It is pocket size. contains 248 pages. with over available, we can furnish them postpaid at of days with thunderstorms at seven sta- 1.000 illustrations and describes in plain, clear fifteen cents each. tions in the United States. A thunder- language all about Bells, Push Buttons. Bat- Q. 2. Is it practical to employ such cells storm day is now defined as one on which teries, Telephone and Telegraph Material, in the construction of a moving pic- or not rain falls Electric Toys, Burglar and Fire Alarm talking thunder is heard whether Contrivances, Electric Call Bells, Electric ture machine? at the observing station. Alarm Clocks, Medical Batteries, Motor A. 2. As far as we are informed, tests Boat Horns, Electrically Heated Appara- on such devices have been fairly success- tus, Battery Connectors, Switches. Battery ful, but we have not heard much lately re- Per Cents. of Ten -year Total Oc- Gauges, Wireless Telegraph Instruments. curing in Each Month a', garding the further development of such Station a 3 Ignition Supplies. etc. apparatus. The subject is a very inter- em á m . 9 ç IT MEANS MONEY SAVED TO YOU one and is, we believe, a pos- á á á é esting there . w ti.9 4. ti C rá O x F to have our Manual and our Catalog when you sibility of such a device being developed want to buy. for commercial use. So far as we know there has been but one extensive article San Francisco Cal 1250 12 0 0 0 o 0 12 o 3 g Manhattan Electrical ever publisht on the use of selenium in Fresno, Cal 3 14 16 14 18 5 3 o 11 8 5 5 37 talking motion pictures, which appeared in Boston, Mass 2 1 4 4 14 17 23 22 11 2 2 1 180 Supply Co., Inc. the June, 1915, issue of THE ELECTRICAL New York, N.Y. 1 1 3 9 14 18 25 19 9 3 0 0 284 New York: Chicago: St. Louis: EXPERIMENTER, which we can supply you Chicago, Ill 2 6 8 15 16 17 16 12 4 2 0 900 17 Park Place 114 S. th Ave. 1106 Pine St. for twenty -five cents, if you have not this Santa Fé, N. Mex.... . o 3 4 9 15 29 24 3 o 732 604 Mission St. issue on hand. San Francisco Office: Tampa, Fla 3 3 10 1724 22 141 3 0 1 944 Q. 3. Will you kindly inform me as to the originator of selenium cells in talking mo- tion pictures. At San Francisco, atmospheric ins abil- A. 3. This dates back to 1904 when Er- ity does not often occur in summer. Fres- nest Ruhmer, the German physicist, de- no has its maximum early probably because veloped a workable model of such a ma- the air is too dry in mid- summer. The chine. other stations have the greatest number in summer. Boston, New York and Chicago t r,. USING LARGE SPARK COIL FOR all have an abundance of moisture. The WIRELESS. greater number of thunderstorms in Chi- (718.) C. Murray, Winnipeg, Man., Can- cago for the year, and particularly in spring, For Wireless ada, asks several questions regarding a 12- as compared with New York and Boston, SPARK COILS inch spark, specially built induction coil. is due to its continental position and ex- STYLE C SPECIAL tt A. 1. We believe that you use a primary posure to rapid temperature changes. The Postage extra COIL $3 50 condenser much too large; i.e., made up of interior location favors more rapid warm- 7 -2 mfd. condensers connected in paral- ing in spring than is the case in the east. FINE RESULTS WITH THIS COIL lel. Your spark coil appears to be heavy Even New York appears markedly more SCHUG ELECTRIC MFG. CO. enough to qualify as an open core A.C. continental than Boston. It is noteworthy 254 EAST LARNED, DETROIT, MICH. transformer, and you should be able to sat- that there are more thunderstorms in May isfactorily operate it from the usual A.C. than in September; May is moister; and the circuit, with a suitable rheostat; or, better upper air is colder. The great thunder- Learn Watchwork, Jewelrywork and an adjustable iron core impedance in series storm activity at Santa Fé is favored by A fine trade commanding a good sal- it to the current. löcation (altitude 7,013 feet) Engraving. ary, and your services are always in with control It also the mountain demand. Address HOROLOGICAL Department. should work very well with an electrolytic east of the Rio Grande. In June, July and Bradley Institute, Peoria. Ill., for our latest catalog (Continued on opposite page) (Continued on page 840) You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER

QUESTION BOX. ( Continued from paye 836) interrupter and a choke coil in series to reg- THIS FAMOUS ELECTRO -SET CO.'S ulate the current. When it is used in this way on 110 volt A.C. circuit, a kick-back preventer of an approved pattern, should be connected directly across the primary HANDY BOOKAND CATALOGUE terminals of the coil and thoroly grounded. This coil should give you good results for r wireless purposes and we should imagine that it would give you in the neighborhood of % to 34 k.w. depending upon the regula- tion of the current in the primary circuit. You will find a great deal of valuable in- formation in this direction in our excellent twenty -five cent handbook entitled "How to Make Wireless Sending Apparatus." BOOK QUERY. (719.) The T- M- .Co., Muscatine, Iowa, asks for information on books: A. 1. We refer you to our Book Catalog 71'o EIocti'O-sot (ós in which you will find a number of excel- lent books listed on high frequency ap- paratus, induction coils, etc. HANDY BOOK We can supply a copy of the book en- tilt titled "The Design and Construction of In- Postage Paid to duction Coils" by A. F. Collins at $3.15 pre- Anybody -Anywhere paid. We can also supply you with the CATALOGUE This is the BIG BOOK you need and want. EDITION B-2 book "Induction Coils, Their Theory, De- By actual comparison, the Electro-Set Co.'s sign and Construction," by H. Armagnat Handy Book contains moro information ELEC i ?iCAI THINGS than any tiro twenty -five cent books on the for $2.10 prepaid. An excellent work on market. For a limited time we will send FOI) VEI)YBCDY Liquid Air by Sloane, which covers the ma- this big, valuable book to those interested king of snowballs, etc., artificially, is worth absolutely free of charge. Don't even send us 'The Co. $2.00. postage. Just write your name and address Electro set plainly on a postcard, say "I'm interested Leadei'Nows Bldg. Cleveland O. in your goods." LOCATING BURIED GOLD AND Price 25 cents SILVER DEPOSITS. A Few of the Interesting Items (720.) Geo. H. Gibson, St. Louis, Mo., You Will Find 'tithe Handy Book writes : Treatises on Wireless Telegraphy; Simple Electric Measurements; A. B.C. ofyElectnc- Q. 1. Can you advise me of an electrical ity with many fascinating experiments; apparatus that will accurately locate gold Construction of Aerials. How to Drake Selenium Cells; Calculate Wave Lengths; and Code Charts. and silver deposits in the ground? Tables and Date on Transmitting Ranges; Spark Voltages; Inductivity; Weights and Measures; Wave A. 1. We do not know of any device Lengths; Specific Gravity; Resistance; Wire Data; and Spark Coil Construction. which will intercept and interpret or make manifest the extremely minute electrical Headquarters for radiations, if such they are, sent out by the Wireless Goods RED HEAD WIRELESS RECEIVERS vibrations of the atoms in chemicals such THE LAST WORD IN SENSITIVENESS as gold or silver buried in the ground. Big Values at Low Prices In Wlre By actual test they are from 10 to 27 points Some success has been claimed in locat- less Goods, Motors, Flashlights, Nov- more sensitive than any other standard make. elties, l'art s, Raw Materials, Wire, A great New York Testing Engineer reports ing such metallic deposits if they are not Heating_ Appliances, Lighting Plants, take goods. highly in favor of Red Head Receivers. You buried too deeply with the Hughes' induc- Toys, Train Sets and other no risk! 5 days' trial -and then if they do not tion balance, which was described on page Read about our fill every expectation we send your money back. 260 of the August, 1916, issue of THE ELEC- "Red head" Wireless Receivers 4 PRICES 1 -0 K. W. Wireless Transformer e 2000 ohms. per pair, complete set, with TRICAL EXPERIMENTER, a copy of which can 31.00 Telegraph Set head band and cord $5.00 be obtained at 15 cents. 1000 ohms, single receiver only 175 $1.00 Electrical Outfit 1000 ohms, single set, with cord and band 3.00 RADIATION FROM WIRELESS $4.00 Professional Tuner Send for our Free Booklet before buying wireless receivers STATION. Audion Detectors (721.) L. A. G., Los Angeles, Cal., writes Storage Batteries us concerning his radio station and the Raw Materials theoretical efficiency of the same as com- Binding Posts BIC TRIAL OFFER puted by the usual formulae. Experimental Goods To "Experimenter" Readers Send the Postcard TODAY A. 1. The reasoning and formulae as set For the purpose of further introducing forth in Mr. Whitney's article in the No- our already widely known super-sensi- vember, 1916, issue of THE ELECTRICAL Ex- SPECIAL PURCHASE tive Triple A Grade Wireless Min- erals, we offer for a limited time only PERIMENTER, are correct. There was a AND SALE OF GENUINE this trial size package of A A A made in out small discrepancy carrying the RUMKORFF STYLE W.reoega here N computations incident to working the for- GALENA syye- mula as mentioned on page 671, December 10c c dpi of ioc in stamps or coin issue, but the formula Itself and the terms SPARK COILS Nearly all serious wire- Send today for this trial package therein are correct. $4.00 less . experimenters are of Famous Electroset Galena. If $1.95 faliarmi with our won- you do not find more sensitive You will find this method explained in Value derful wireless minerals. spots in this small trial all of the radio handbooks, including those We bave secured a limited lot e d fine Hundreds of testi- package than you can getout by Dr. A. Fleming and Dr. Eccles. 14-Incb Rumkorff style spark coils, monials prove our con- of 8 oz. of ordinary galena, we J. classical design, with condenser mount- tention that no min- will gladly return your dime. column has had ed In a beautiful mahogany finished The editor of this some erals marketed today NOTE: Do not confuse this offer experience with this radiation current for- base, spark gap, and special current can compare in sen- reversing switch, complete with heavy sitiveness to our with our regular Arlington Tested mula and the terms therein vary of course vlbiatcrs and handsomely finished in standardized grades. individually Packed Galena at 25e is every detail. These colis were design- postpaid. Arlington Tested Gal- for different designs of aerial. It found ed to sell at 54.00 eacb. By a fortu- We make an unlimited ena will be sent if requested? upon nate purchase we are able to otter guarantee that obviates that for your case, and considering the nat- them, until sold, at the very remark- receipt of 25c in stamps or coin. all risk -Your money Arlington is endirldaatlu ural or fundamental wave length of your able price of $1.95 each. Shipping if Galena weight 5 lbs. They will actually give back you are not tested for erbrme distances and 1s inverted "L" antenna squared as 5.700,000, Item M to d-Ineb spark. Toavold dis- satisfied. ultra -super- scn.cirtoe. the radiation in watts would be 24.8 and appointment send in your order today. Send For The Bargain Trial Galena Today the net efficiency of the station 24.8 divided by 1,350 1.84 watts input or net efficiency, ADDRESS DEPT. E -9 which is nearly 2 per cent. The different quantities here involved are THE ELECTRO -SET CO CLEVELAND, OHIO not very explicitly stated in your letter and the low efficiency in either case might he ELECTRICAL THINGS FOR EVERYBODY (Continued on page 840) You benefit by me 'Honing "The Electrical Experimenter" when waiting to advertisers.

www.americanradiohistory.com I 838 THE ELECTRICAL EXPERIMENTER ' March, 1917 NEW MODEL INSTRUMENTS New York City, N. Y., February, 1917. LOW. This advertisement -the greatest wireless announcement MR. WIRELESSPAS AMATEUR, of the year - proves it amply. Anywhere, U. S. A. The E. i. Co. has the brains -and delivers the goods. My Dear Sir: -Perhaps you have heard of the Electro Importing The E. I. Co. is known give everyone Co. before. Perhaps you aretono of the countless satisfied users of to universal satisfaction. E. I. Co. apparatus. But do you know these FACTS which can be The E. I. Co. is famed for its SQUARE DEAL. readily proved by any? The E. I. Co.'s standing makes it absolutely safe for you to deal The E. I. Co. is the oldest electrical experimental supply house with us. You ALWAYS save money. in the world. Established in 1904 -13 years old. The E. I. Co. con- The E. and courteous trols more wireless and kindred patents than any other similar es- I. Co. gives you prompt treatment. tablishment in the United States. The company controls ALL the The E. I. Co. has issued its new Catalog No. 18 containing a patents of the undersigned, manufacturing and selling all appa- wealth of new articles and information. The free coupon brings it. ratus under these patents. Respectfully yours, The E. I. Co. today probably does the largest volume of business in Radio and Experimental Apparatus in the United States. The THE ELECTRO IMPORTING CO. E. 1. Co. ALWAYS has blazed the way -WE LEAD, OTHERS FOL- H. GERNSBACK, President

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The Electro Radio Tone. The newest thing in wireless. 3000 A perfect test buster at lust. Has rubber composition case, Is absolutely noiseless, gives a beautiful high pitched mu- sical note and can't get out of adjustment. Our catalog !bows OHMS several new uses for this instrument. As always. it is the best on the market. Shipping weight, 4 os. Nc. HX-1800 Electro Radio Tone. $0.80

_--leseweee,F7 .:. pmegialmip y Trans -Oceanic Un damdamped Wave Loading Coil- 15,000me- tors capacity. The biggest and best coil of Its kind ever devel- oped. Note the size. (32x8x8 in.) Wound with green silk wire on special tubes. Frame of hand - Our "Government" Receivers have for years been rubbed mahogany. Metal nick- a standard for all to look up to. They have aluminum el plated. Switch Navy type. shells, 5 silk cord perfect diaphragms, ft. and are now Value twice what we ask. Ship- Arlington (NAA) Baby Timer. 12-0 meters wavelength. supplied with the wonderful "Gernsback Adjustable" ping weight, 5 lbs. All that Its name implies and more. Receives long waves Headband. Shipping weight. 3 lbs. No. HEK -4500 Trans- Oceanic Perfectly. Has Bakelite front and hand -rubbed mahogany No. FIX-6666 "Government" Wireless Undamped Wave ease. All metal nickel plated and polished. Size. 35%x6:2. $8.50 No. HEK-4433 Arlington (NAA) Baby Timer $8.50 Receivers $8.00 Loading Coil (no phones). Weight, 4 lbs.

200 TO 1200 METERS WAVELENGTH Electro Professional Wave Meter. -Tbe simplest and best instru- ment of lts kind ever offered the public. Has two exploring coils for dif- Professional Loose Coupler. The 1917 model of the best coupler on ferent capacities. Is supplied complete as shown with full directions the market at its price. the size, Tunes up to and calibration curves. Woodwork band -rubbed mahogany. Shipping Note 15%x7Mx7jq. weight. 10 Iba. Reads from 180 to 1800 meters. Accurate to within 3000 meters easily. Navy type switch on secondary with 10 points. 3 weight. No. HZ-4488 "Professional- Wave Meter. $8.00 No. HX-14000 Professional Loose Coupler $8.00 THE ELECTRO IMPORTING CO., Mfrs. 231 Fulton Street, New York, N. Y.

www.americanradiohistory.com

March, 1917 THE ELECTRICAL EXPERIMENTER

FROM CYCLOPEDIA CATALOG NO. 18 USE THE COUPON BELOW TO GET YOUR FREE COPY OF THIS BIG BOOK. "ITS THE LIVEST CATALOG IN AMERICA"

Tuckerton (WOO) Radio Outfit. Receives long and situri; waves in great style. Has the most wonderful Navy type loose coupler you have ever seen. All fronts of Bakelite, metal nickeled and case of hand- rubbed mahogany. Size, 2l)4x7x03in. Shipping wt., 15 lbs. $26.00 No. BFX- 4466 Tuckerton (WOG) Radio Outfit (no phones).

Sayville (WSL) Radio Outfit. 2500 meters wavelength. A de luxe cabinet that is compact, efficient, good looking and yet Is not expensive. All tuning is by switches, and the front Is of Bakelite, the metal highly nickeled and the case is of hand- rubbed mahogany. Size, 12x10x53, Shipping weight. 0lbs.$ No. AHX -4455 Sayville (WSL) Radio Outfit (no phones) 18.00

`0

Key West (NAR) Radio Outfit. 2000 meters wavelength. Com- bines more value in a small outfit than any outfit we make. Has made some wonderful long records in tests. Bakelite front, nick- eledmettal, and hand -rubbed mahogany case. Size, 8x8x4H. Shipping . A -4444X KeylWest (NAR) Radio Outfit (no phones) 14.00

Nauen (POZ) Radio Outfit. 3500 meters wavelength. Made to do .joist what its name implies, to receive European messages. and does it. Has a remarkable Navy type receiving transformer and condens- ers. Entire front of Bakelite, metal highly nickeled and case, size 17,4 x11j4x7, is of hand -rubbed mahogany. A perfect instrument at a very reasonable price. Receives up to 3500 meters without extra coils. A real bargain. No. 477 Nauen (POZ) Radio Outfit (no CIX-0 $39.00

COLD WIRE CATWHISKER Yee, entirely free. Our bi^, newEE electrical cyclopedia No 1g is waiting for you. Positively the most complete Wireless and Radiocite Detector. The newest and best on the market. Most easily electrical catalog in print today. 200 Big Pages, 600illustra- adjusted and only one that LOCKS its adjustment. Radiocite crystal tions, 530 instruments and apparatus, etc. New art Section furnished; also solid gold catwhlsker. Heavy Bakelite base. shipping contains finest Radio Outfits made. Big Treatise on weight, 3 lbs. Wireless Telegraphy." 20 FREE coupons for your 100 -page No. CE K-8888 Radiocite Detector $3.50 FREE Wireless Course in 20 lessons. FREE Cyclopedia No. 18 measures 7x5 11'. Weight 55lb. Beautiful stiff covers. "THE LIVEST CATALOG IN AMERICA" Now before you turn this page write your name and address on margin below, cut or tear out. paste on postal card and the The Electro Importing Co., Mfrs. Cyclopedia is yours by return mall. 231 FULTON ST., NEW YORK THE ELECTRO IMPORTING CO., 236 Fulton St., N. Y.C.

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www.americanradiohistory.com 840 THE ELECTRICAL EXPERIMENTER March, 1917 QUESTION BOX. THUNDERSTORMS OF THE alliMesW (Continued from page 837) UNITED STATES. . (Continued from page 836) due, we believe, to the fact that the aver- s0s! age primary input is assumed too high, viz., August there is, on the average, a thunder- 1,350 watts. The usual arc potential is storm every other day. Thunderstorms are When you get that thrill- less than half as frequent at the drier, low- weak you will about 70 volts. What your true watts in- ingly SOS put for the six arcs in series is, we do not er places such as El Paso. Tampa has appreciate the remark- know. more thunderstorms than any other weather able sensitiveness of our bureau station in the United estates. In Head From the general expression for the ra- Improved Type A -9723 diation current, resistance and wattage, it the three summer months, thunderstorms Set. Read this from an amateur occur on about two days out of three. The Ga.: is apparent that the greater the wave length wireless operator of Athens, the lower the efficiency becomes. It has summer on -shore winds supply abundant "1 have for months been nightly reading amateur been found that with arcs the best efficiency moisture and the intense sunlight at this stations -on Galena detector- anywhere from 400 low latitude effectively the lower to 1500 miles distant, some of them wing less than is realized in any certain station, excited overheats 1 kw., and tests with other phones of higher price with a small arc, when the radiated wave air. Thus the joint distribution of atmos- than yours fail to give any signals at all from these pheric instability and moisture dominate stations." (Name on request.) length is not markedly greater than that of the fundamental of the aerial. The effi- thunderstorm frequency. ciency can also be increased by elevating Parts of Professor Ward's abstract says Stromberg- Carlson the aerial as pointed out in Mr. Whitney's among other things : discussion and three amperes of radiation "As essential characteristics of American Radio Head Set current as indicated by your hot wire am- climate, thunderstorms'ave a broad, human You will probably find this improved type meter seems to us quite low. interest. From the viewpoint of climatol- A -9723 Radio Head Set -wound to 2000 ogy, the distribution of thunderstorms is of ohms -at your dealer. If not, we will WHAT IS A CANDLE -POWER? more interest than their mechanism. The send it direct for $8.25. Keep it ten days. in If it does not do all that we claim for it. (723.) Philip Ansis, Detroit, Mich., asks: part played by their rains watering our if not satisfied that it is the best buy on the Q. 1. In illuminating work. what is meant crops is of greater importance than the size market, send it back and we will of the raindrops. The damage done by refund money without question. by a standard candle -power? A 1. The amount of light emitted by a their lightning and hail concerns us more Send for Balktin No. than the cause of the lightning flash or than 1006 -C giving full sperm candle seven -eighths of an inch in description diameter and burning at the rate of 7.776 the origin of the hailstorms. The thunder- grams, or 120 grains, per hour. storms of the eastern United States are Stromberg- Carlson among the most characteristi- of American Telephone M1g.Co. Q. 2. What do you mean by lumen? A. 2. The standard of luminous flux, be- climatic phenomena. In size, intensity and Rochester, N. Y. ing the light radiated from a unit source frequency of occurrence they are unique. thru a unit solid angle. i(We agree with him. -Ed.) 3. Define mean "In relation to man's activities. it is of Q. hemi -spherical candle- occur Get up-to-date in Rouse power. significance that most thunderstorms a year and at the hours when LABOR:nM.tRIALhy using A. 3. If there be drawn, from a source at time of El r 98 Gamine Btu¢. PRINT at height. li the equally in all directions either below or outdoor activities are their latest diagrams and connections known in bouae wiring -- -every di "Thunderstorms bring us much that is of and connection up.to.the minute as used by first class elecMciannss for above the equitorial plane, lines whose wiring 4:uó. Ruxel.AR Attests Liners. ANNUNCIATORS, Fire benefit. To we owe much, in parts and ELELECTRIC GAS LIGHTINe. These drawings are hound in the form of lengths are proportional to the candle-pow- them book 9 x 121 for convenience in using on the job. Send for even most, of our spring and tflexiblehem, and if they don't make you more efficient as a wireman and save er in these directions, then the mean value of our country many times their cost as a ntractor return them and money these beneficent woill he refunded - --you can't to be without them. ONE DOLLAR summer rainfall. Without post of the lengths, either above or below, is thç paid. mean hemi- spherical candle -power of the thunderstorms our great staple crops east PATENT SPECIALTY COMPANY of Rocky Mountains would never reach 462 upper or lower hemisphere respectively. the Sanchez Street San Francisco, Cal. maturity. One good thunderstorm over a considerable area at a critical crop stage training are always In RADIO TELEPHONY. ELECTRICAL demwithand. Having trained is worth hundreds of thousands of dollars 2Mq Young men 1 ehe tv23 (724.) Otto M. Johnson, Seattle, Wash., the fundamentals of Applied EleeMCit 1He BLn5 tl EeTRl. American farmers. Our stock markets CALSr'n nouL, with its well-equipped shops and laboratories, is peculiarly. inquires : to qualified to give a condensed course in Electrical time and again show the favorable reaction Q. 1. I am enclosing a diagram of con- of cer- nections for a wireless telephone of such conditions upon the prices ENGINEERING sending eals and also of railroad and other lytIncluding Mathematics, Steam and Gat En- gines. and stocks. Thundershowers break our summer and Prlacrtial Electt°,kn branches. Students actually Construct dyna- droughts, cleanse our dusty air, refresh our and efficiency élecirical machinery. i loma. parched earth, replenish our failing streams complete and brooks, bring us cool evenings and ONE YEAR nights after sultry and oppressive days." For pINn

s two Bargain ! Engine offers economical power for every puryose. Many new, exclusive future' ,Inclut throttle gov- ing arrdt` governed. Suernor,rprisingly low cost. Burns kerosene or gasoline. Runs machinery, umps runs separator, churn:, etc. Catalog detmlla reee C. Benninghsfen & Sens, Hamilt Wireless Telephone Hook -up, Using Audion to Dept. 110 -A Obis Rectify Oscillations, as Proposed by Querist. set, using an Audion detector as a recti- fier. The diagram explains it better. I OSTON WIRELESS wish to know whether it will work well. The lead from the arc is connected to plate BRotary Condensa', 43 plates. .001 M.F., 53.75 and lead to primary from the grid. The Tuner 52.50. Spark Gaps 60e. and $1.00 Detectors, 51.00, SI.i'S, 54.00 microphone is in series with aerial. If it Loose Coupler, 57.50. 1500 M will not work, please publish a diagram of Agent for A. W. Bowman Sr Co., Adams -Morgan Co. Manhattan Spark Coils. Catalogue for 20. stamp a circuit that will.

I A. 1. Your diagram as submitted to us M. MUELLER,18 Devonshire Street, BOSTON, MASS will not work for the reason that the high from L'OR. SALE CHEAP -one electric tension current the transformer will auto. -(coupe). Baker- Cleveland type. pass between the electrodes of the Audion Five years old but in Al Condition equipped DETECTORS!!! as these are very close together. Further- with new Exide batteries. Forced to sell Ask for our bargain lists. We hare DeForeet New and more, if rectification exists, very few oscil- on account of illness of owner. Machine can burnt out Detector and Amplifier bulbs, $2 to $5.50. A few be Inspected In New York City. Write for double 5lameat, tubular bulbs, $:1.50; single filament lations would pass thru the antenna circuit. particulars at once. No reasonable otter tubes, 52.50; LENZITE detectors, $3.50. Quartered oak, may is con- refused. FORMICA paneled bulb cabinet.. from $2 to $8.00. Re- It work if the tube of large generative Short wave amplifie, with bulb. $21.50. Expert struction. so as not to permit the high ten - lathe work, FORMICA INSULATION wire. Agents for sión current leaking from one terminal to Box No. 77, c/o Electrical Experi all high grade apparatus. Let os quote you. menter, 233 Fulton St.. N. Y. City Mid -West Wireless Supply Co., Mattoon, 111. the other. (Continued on page 842) You benefit by mentioning "The Electrical Experimenter" when Writing to advertisers.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 841

LONG DISTANCE WIRELESS RECORD. WEACO SEMI -QUENCHED ROTARY GAP A new world's wireless record for long distance work has been established on the BAKELITE CONSTRUCTION 600 -meter wave length. The steamer Flori- LESS CONDENSER dian left San Francisco for Sydney, Aus- talia, July thirteenth. From that date up GREATER RADIATION to and including July thirty- first, the ves- SEMI -QUENCHING sel's position was transmitted to San Fran- A semi -quenched rotary gap utilizing the cisco. The position reports, with one ex- Venier principle. applied for the first time in the construction of an entirely enclosed ception, were received directly at the Mar- gap. Practically noiseless in operation. coni Hillcrest station, San Francisco, up Enclose 2 cent stamp tor Bulletin. to a distance of 5,227 miles. The Floridian is equipt with the stand- WIRELESS EXPERIMENTAL APPARATUS CO. ard Marconi two -kilowatt, 500 -cycle panel 130 NORTH 62nd STREET, PHILADELPHIA, PA. set. The current consumption at the trans- former did not exceed 1,600 watts up to 2,600 miles, and at 5,290 miles the power DID YOU SHOW YOUR FRIEND THE LAST ISSUE? consumed was 2,600 watts. San Francis- and we will all win out co's signals were audible up to some 3,000 He will appreciate it, you will help us miles. Make sure he sees this copy, especially page 862

THE INCOMPARABLE Tigerman. Detecto- Amplifier Pending THE ONLY DEVICE INVENTED WHICH TAKES THE PLACE OF TWO ORDINARY DETECTORS PANEL RECEIVING SET CABINET RECEIVING SET SOME OF ITS MOST SALIENT FEATURES ARE: s Oscillator and Orte Step Amplifier for receiving undamped ware signals and intensifying it 10 to 25 limes. Detector and One Step OK Off ON or, Amplifier for receiving damped wave signals and intensifying it 10 to 25 times.

s Detector and Oscillator -t for receiving both damped and un- i -t damped wave signals. Two Individual Detectors ÿ Two Individual Oscilla- tors EN P P Two Step Amplifier used in connection with another detector. Price of Individual Tube, $7.00 i Type "E" with Han cl Rubber or Formica Panel, $27.50 The length of the Tigerman tube is SW' Type "A" Hard Rubber or Formica Panel - $20.00 Type "G" with Mahogany Front Panel - - - 22.50 Type "C" Mahogany Panel 16.00 Below are some of our authorized representatives who shall be glad of the opportunity to demonstrate and prove to you the unequal superiority of the TIGERMAN DETECTO- AMPLIFIER. If any of them near you call on him and be convinced. BEAVER RADIO CO., 439 Nav- HERBERT J. FERRIS, 19 How- ELLSWORTH JOHNSON. 528 NORTHERN STATES WIRE- G. & E. RADIO SUPPLY CO.. igation St.. Beaver, Pa. ard St., Detroit, huch. 13th St., S.E. Minneapolis, LESS CO., 232 S. Duluth Lowellville, O. BROOKLYN ELEC. LAMP & SETH W. FULLER ELECTRIC Minn. Ave.. Sioux Falls. S. D. THE RICHARDSON CO., Erle, NOVELTY CO.. 278 Fulton CO., 100 Bedford St., Boston, LYNN KEATON. N. Broad St., WERT O'DONNELL, 1222 W. Pa. Street, Brooklyn. N.Y. Mass. Norwich, N. Y. 30th St., Indianapolis, Ind. M. E. ROBERTSON 98 Pier - J. STANLEY BROWN, 1323 H. I. GOODA LE, 676 Elm St., ERNEST LAWRENCE, Canton FOLGER C. OUDIN. 7 Union moot Ave.. Nyack, N. Y. Main St., Menominee, Mich. Buffalo, N. Y. Public School. Canton. S. D. St., Schenectady, N. Y. Dr. L. KISMET ROSSA. See., G. V. H. CAIRNS, 44 Rosedale HARRY GOODWIN, 609 Em- KENNETH R. LYDE. 2t1 Clodla PACIFIC WIRELESS SPE- Eastern Panhandle Radio Assn, Ct., Detroit. Mich. erson St., Watertown, N. Y. Terrace. Newtonvilte, Klass. CIALTY CO., 1526 Crenshaw 506 W. John St . Martinsburg. MAURICE CARNEY, Phoenix, IRA GOTTSCHALK, 813 13th JOHN J. MARTIN, 414 S. 3d Boulevard, Los Angeles, Cal. W. Va. N. Y. St., Manitowoc, WIE. St.. Hodpeston. Ill. C. K. PALTER, 110 Maln St., R. A. SEAGER, Ankona, Fla. P. N CLAUSE, 461 No 2nd St.. GEO. GROSSMAN, Box 194. FRANK A. OIeCOWAN, Box West Bend, Wis. L. M. SMITH, Salem. Wis. Call Lehighton. Pa. Columbia, Mo. 381. Mason. Mich. EARLE B. PERKINS, 134 Pine 9MA and 9BV. CLIFF MFG. CO., Brookfield, ROBERT H. HARNING, 29 J. C. MEIGHAMI, 1656 Washing- St... So. Portland, Me. B. STEDINGER. 1414 S. 19th Klass. Westheld Ave., Roselle t Park, ton Ave., Northampton. Pa. PIONEER AUTO SUPPLY CO., St., Omaha, Neb. N. J. can 8TG Twenty -second St. , at Gran IRA F. COON, 526 E. 4th St., Ave., Kansas City. Mo. BRAINERD L. STRATTON. Lockport, Ill. CEO. E. HARRINGTON, Or- MID -WEST WIRELESS MFG. 44 Seneca St.. Oneida, N. Y. J. A. CORBELL. Box 937, Ard- leans. Minn. & SUPPLY CO.. Mattoon. Ill. PORTLAND WIRELESS more, Okla. THE HINZ ELECTRICAL CO. EQUIPMENT CO., Morgan AUGUST J. TETE, B. E., 1516 234 Palmer Ave., Syracuse, N.Y. MIGNON WIRELESS CORP., Bldg.. Portland. Ore. Kerlerec St . New Orleans, La. DEAN COTTAM, La Mourne, Elmira. N. 1. N. D. JOS.M HOFFMANN, 317 E. 91st EDWIN I.. PO W ELL. 216 Spruce II. J. VAN BUREN, 921 Marshall MAURICE J. CRAVEN, Spring St., New York. MODERN ELECTRIC SHOP. Ave , Takoma Park, Md. Ave., Newcastle, Pa. Call 8QT. Valley, III. Electrical Sales and Installation H. A. HOLCOMB. 117 SprmggSt., Dept., Fourteenth and N. Sts.. RADIO APPARATUS CO. OF E. O. WALTZ. Medina. O. D. N. S. ELECTRICAL LAB- Windsor Lock, Conn. Call 1ATY N. W.,Washingtoa, D. C. AMERICA, Parkway Bldg., ORATORY. Quintan, Okla. Broad and Cherry Sts.. Phila- ASHLEY WILLIAMS. 4300 GLENN DUNFEE, 607 Fifth CHAS. E. HOLMES. 310 Brown M. MUELLER. 18 Devonshire delphia. Pa. South St., Lineoln, Neb. Avenue., Shenandoah. Ia. St.. Grand Rapids, Mich. St., Boston, Mass. THE RADIO DISTRIBUTING THE WIRELESS SHOP. 308 NED EA CHUB, 37 Court Street, THE IRONTON RADIO SALES R. J. NICHOLS, 401 Litchfield CO., Lombard. Il . Brown St., Ypsilanti, Mich. Gallipons, O. Co., 510 S. 7th St., Ironton, O. St., Bay City, Mich. THE RADIO RESEARCH LAB- WORCEST ER RA D I O LA BO R- LESTER S. FAWCETF Inde- LESTER I. JENKINS. 74 Smith STUART NIVLING, 130 Aber- ORATORIES. 2148 Fifth Ave., ATORIES, 16 Wayne Street, pendence, Ia. Call 9AIi1'. St., New Bedford, Mass. deen St.., Rochester. N.Y. Troy, N. Y. Worcester, Mass. This detector does not employ or incorporate an evacuated vessel containing three electrodes. namely, a filament, a plate. and a grid disposed between the filament and plate. LEARN ALL ABOUT ITI SEND NOW FOR FREE DESCRIPTIVE CIRCULAR

I National Electric Manufacturing Company 608 S.. Dearborn St Chic, III.

Yon benefit by mentioning "The Electrical Experimenter' when writing to advertisers.

www.americanradiohistory.com 842 THE ELECTRICAL EXPERIMENTER March, 1917 QUESTION BOX. (Continued from page 840) Q. 2. In the January, 1917, issue, page 693, Wireless "Mile- Makers" The American Technical Society publisht a diagram of a radio sending and receiving set. They claim it is the best circuit yet. flow Please give description of instruments if Greater sending range- steadier current - possible. A. 2. The circuit of which you speak is more accurate adjustment -these are the reasons the one which the Marconi company was using at the time they employed the mag- expert operators prefer netic detector for receiving. This hook -up is very selective, but is little used nowadays. DECOMPOSITION OF WATER. (725.) Harold Nehls, Kilbourn, Wis., de- sires to know the following: Q. 1. How can an alternating current de- THORDARSON compose water, so that one -half cycle of the current will decompose the water to re- WIRELESS TRANSFORMERS ceive one atom of oxygen, and the other half of the cycle will obtain two atoms of Perfected by the same engineering hydrogen: A. 1. It is impossible to decompose water skill that has won for Thordarson by means of an alternating current, as the time interval of the alternating current is high- tension transformers the Gold so small that there is little chance of decom- posing the water. However, the alternating Medal at the St. Louis and Pan- current can be converted into a uni- direc- ama - Pacific Expositions. tional current by employing some form of Made rectifier, which may be either electrolytic, like a watch and sold only com- mechanical or electrical and then using the rectified current for the decomposition pletely assembled. Five sizes, work. to 2% K.W., 10,000- 20,000 volts, GENERATOR QUERIES. any cycle desired. (726.) A. Baldock, Middlechurch, Mass., The Variable Shunt (marked by wants to know' arrow) is an exclusive Thordarson Q. 1. What factor governs the current in Write for Special Bulletin feature enabling the operator to amperes an A.C. or D.C. generator will attain perfect resonance byreg- and Prices alating the air-gap. Locked in deliver? position by eccentric cam. A. 1. There are several factors in gene- rator design and construction which deter- 506 SO. JEFFERSON STREET Thordarson Electric Mfg. Co., CHICAGO, ILL. mine the number of amperes delivered by the machine, but principally the size and number of the conductors used on the ar- mature. It is usual to allow 600 circular mils per ampere for armature conductors. Multi= Audi =Fone Q. 2. What factor determines the pres- sure it will "throw" on the line? A. 2. The number of conductors, size of M.A.F. Wave Regen- the field coils and the speed of the arma- Short ture are the main considerations which af- erative Attachment fect the pressure (e.m.f.) delivered by a The M. A. F. Short Wave Regenerative Attach- given machine. Thus a generator having a ment is the latest and highest achievement in the large number of conductors will deliver a field of regenerative circuits. greater voltage than another machine of \ %'hen this Instrument is attached to your present the same construction, but fewer cop- loose coupler and Audion you will be able to receive with those long distance relay messages. per conductors. The speed of the armature With this M. A. F. Attachment the operator is able is one factor which controls the voltage ; to receive amateur and commercial stations ranging the faster the armature rotates the greater from 150 to 3.000 meters- damped and un- damped- the be. of a most remarkable degree. voltage will Also the number of and amplify both them to magnetic lines of force delivered by the Size 8 x 12 Price 522.50 field coils are important, which quantity of course is controlled by the number of turns Multiform Receiver on the field coils and the current passing The Multiform Receiver Is the latest development thru the coils (ampere- turns). and most advanced step in the wireless field and gives Q. 3. What dimensions, i.e., amount of to the operator that comprehensive instrument that be has long looked and hoped for-that Is a single re- iron, amount and size of wire, etc., should ceiving set which combines a straight Audion. circmt, an alternator have? the new regenerative circuit and long wave Un- damped circuit. A. 3. It is impossible for us to go into On any ordinary aerial the Multiform Receiver lengthy details here as to the design and has a wave range running from 150 up to 15.000 meters. construction of generators in this column, as it requires considerable space to cover Multi- Audi- Fone,$18.00 Pocket Wireless Set, $S.75 Two -Step M.A.F., 75.00 Detectorfene 35.00 this. We would advise you to refer to some M. A. F. Detector Stand 4.25 standard text book dealing with this sub- ject. There are a number of such text- Send 2c for Circular books on the market which are very simple MULTI -AUDI -FONE and easily understood. Write our Book 275 Morris Avenue Elizabeth, N. J. Size 24217x12 Price $100.00 Department asking for a list of them. "BEAT" RECEIVER FOR RADIO. EFFICIENT TUNERS AT LOW COST (727.) Kent Aitken, Tilden, Ill., desires Increase your receiving distances by getting our efficient tuner with to know : switches -the biggest value ever offered for only $8.00. Q. 1. How to construct a high frequency Big Undamped Receiving Transformer, 20 taps on primary, 14 on alternator similar to the one described in secondary and brings in the German stations fine, only $12.50. 15,000 Meter Loading Inductance in quartered oak case with 9 taps, the October, 1916, issue of THE ELECTRICAL only $8.00. Send 2-cent stamp for bulletins. EXPERIMENTER to be used to receive un- COLBY'S TELEGRAPH SCHOOL Auburn, N. Y. damped waves by the "beat system." A. 1. The high frequency alternator de- You benefit by mentioning "The Electrical Experimenter' when trritir g to advertisers.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 843 scribed in the October, 1916, issue of THIE ELECTRICAL EXPERIMENTER can be used for producing beats such as used by Prof. Fes - ',We '&4..4...4 senden in his heterodyne receiver. We would advise you, however, to build the generator with more pole pieces on the rotor than the one described, in order to obtain a greater frequency at a reasonable speed. 411ii > Q. 2. How would the alternator be con- 3w.. nected with a loose coupler, loading coil, s. s,.ye atiau. fixt condenser and receivers? WDS tiá:á. n.w A. 2. The accompanying diagram shows the connections of the alternator in con- junction with the instruments you mention. 44.1 .ww.a 4Nr,n Due«. The only additional instruments required or root no . nn4r.4r a. are an inductively coupled coil and a vari- u. nnm4,q.W.yyra:e.roe able condenser. The alternator is linked ono. ..y, .r .4b. on inductively with the primary of the loose ala w.»e.tÿ`F iurL 44,44e. y. or t w . tin ..,a, >Mao ` coupler, thru the ground as will be per- . ... , "bk or , ' r4., nor w ceived. tar r. Q. 3. Can I receive undamped waves n.ay tut ry.»sDt44 ru4tItu nrsUw or bt.e'a. ..,,t ,.ehy, r with the above instruments with an aerial *oft to tnlaaa.. y,DDny soon w 66 feet long and 40 feet high? w ,.4. ..4 í A. 3. Yes; providing you employ large enough loading coils to tune the wave d1son KnovS! i.._ length which the undamped wave trans- mitter is emitting. 'a HUNDREDS of thousands of men who have won and are winning success through the International Correspondence Schools will thrill with pride when they read this splendid tribute 1M* from Thomas A. Edison. For Edison knows! He knows the worth of spare -time study. He knows what stuff men are G made of who use their spare hours to train them-

V. selves for the bigger jobs ahead. And he knows G what the I. C. S. will do for the man with the Q 7 17 grit to say, "I will. How High Frequency Alternator (H.F.A.) is Linked Up With Antenna Circuit in Order to Produce "Beats" for Receiving Undamped Waves. Wasn't it Edison himself who stayed up half the night to read every get -at -able book on elec- RESISTANCE MATERIAL. (728.) Fritz G. Chappies, Callao, Peru, tricity ? Didn't he educate himself in spite of S.A., asks: every handicap you could ever have? Q. 1. Which will be the best material over which to wind resistance wire for electric stoves provided mica is not available, and All big men who have made their mark in the what will be the best insulating composi- world had the ambition tion to secure the saine resistance wires in -the determination -to place? improve their spare time, to train themselves for A. 1. If mica is not at hand, the next best material to use for winding the heating unit big work. You, too, can possess power, money is slate, porcelain or soap stone. German 1- --1CAa OUT Mxax- silver wire is often used for making up the and happiness if you'll ------heating element. However on larger units, INTERNATIONAL CORRESPONDENCE SCHOOLS make the effort. Box SCRANTON, is em- only 5336, PA. special composition wire usually Explain, without obligating me, how I can qualify for ployed. The reward is great -it's he position, or in the subject, before which I mark X. Q. 2. Should the wires work to a red ADVERTISING MAN ELECTRICAL ENGINEER Salesmanship Electric Lighting heat, or what will be the best working tem- worth it. Commercial Law Electric Car Running BUSINESS (Complete) Electric Wiring perature? Cert. Pub. Accountant Telegraph Expert A. 2. The wires should be kept just a all we ask: Higher Accounting Practical Telephony Here's Bookkeeper Railroader shade darker than cherry red. This tem- Stenographer and Tya it Rine Foreman or Engineer perature is best, as the heat developed at Merely mail this coupon. Railway Accountant netallurgi't or Propeetor WINDOW TRIMMER ARCHITECT this point is quite intensive, but not too Show Card Writer Contractor and Builder in good shape. Put it up to us without Outdoor Sign Painter Arehltertotal Draftsman much so, to keep the wire Cowmen School Sublease Concrete Builder Fine Portland cement is recommended as Good English Structural Engineer paying or promising. Let Teacher Plumbing and Heating a filler to keep the wires in place. After it Civil Service Sheet Metal Worker has the heating unit is compact and us details of Railway Mail Clerk CHEMICAL ENGINEER "set." send you the CIVIL ENGINEER Illustrator rigid. Rheostats are built in this manner. Surveying and Mapping Designer others' success through MECHANICAL ENGINEER Textile O or Snots Mechanical Draftsmen AGRICULTURE Spanish ALTERNATOR QUERY. Machine Shop Practice Navigator German the I. C. S., and then Stationary Engineer Poultry Ifaleinr trench (729.) L. Weiss, Brooklyn, N.Y., wishes Gas Engineer AUTOMOBLEIS IWian to know: decide. Mark and mail Q. 1. What advantage have constant cur- rent alternators over constant current dy- this coupon now. Present namos? IOccupation Street A. 1. high pressure is deliv. INTERNATIONALCORRESPONDENCESCHOOLS The current Iand No ered to the external circuit without a com- Box 5336, Scranton. Pa, mutator. hence there is no sparking diffi- I City State of Goutaa you want in not in taie lia,, write it below. culty. This relates to the revolving field 1 If name You benefit by mentioning The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com 844 THE ELECTRICAL EXPERIMENTER March, 1917

type of alternator. There are, however, alternators in which the armature revolves, the current being delivered to the external circuit thru collector rings and brushes. It should be noted that this type of alter- FOSCO- nator is for moderate pressures and more- over there is no interruption in the Row of current such as would be occasioned by a tangential brush on a dynamo in passing MOTORS from one commutator segment to the next. In the revolving field machine, altho the from A- to h. p. armature current be of very high pressure, the field current which passes thru the Universal, d. c. or a. c. brushes and slip rings is of low pressure Spark Gaps and accordingly presents no transmission Rotary difficulties. Q. 2. In a constant current series system upon what does the voltage at the alterna- tor depend? This Motor, 6000 -8000 r. p. m., $A .75 A. 2. The number of devices connected in a. c. or d. c., 1 1 0 volts - - 't Electrical Supplies the circuit, the volts required for each, and the line drop. Q. 3. Does the difference in transformer capacity represent all the saving? Send Postage for Catalogue A. 3. No; one large transformer is more efficient than a number of small transform- ers connected to the same circuit. MAGNETIC ATTRACTION. (730.) I. Marks, Clermont, N.J., inquires: The Fosco Corporation Q. 1. How can one calculate the force cohmpletlet- 1.50 with which a magnet attracts another mag- 1355 N. Western Ave. Chicago, Ill. net or a piece of iron? A. 1. The force between the two equal magnets can be determined by the area of the common surface multiplied by the g!III IIIIIIIIi111111ü11111111911111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111IIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII11111111111111111111IIIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIp-' square of the number of lines of force per square centimeter divided by 25.14 or mul- Super - Sensitive Receiving Apparatus tiplied by .04. We have therefore: P - 8- °.04 B'A We have a new and wonderful proposition to offer on Suppose two pieces of iron 1 cm. sq. and super -sensitive receiving apparatus, detectors and access- of any convenient length are bent into two ories. Every one interested in wireless should have it. half circles and that the current is sent thru You had better send for it today -now- before you forget. a coil of wire wound about one or both pieces so as to magnetize the iron to a sat- Equip Your Sets with INDESTRUCTO uration of 5000 lines per sq. centimeter; the Potentiometer Controls force at each point between the two parts. AudioTron Potentiometer and Rheostat Units are made of a special uniform composition and are designed to give silent, easy and close adjustment of battery of the ring will be t14x1x5000x5000=.04x potentials by a constant and gradual increase not possible with one cell variation. 25,000,000 = 1,000,000 dynes; the total force This results in maximum sensitiveness. The will be the sum of that at the two joints, B battery unit is of 7000 ohms resistance, in- suring long life to the batteries. Any lower re- or double that at one, hence, the total pull sistance wastes your battery. The AudioTron is 2,000,000 dynes. Since 981 dynes equals Indestructo Filament Rheostat, having no the weight of one gram, the total pull be- wires to corrode, lasts a lifetime. Its ease of by adjustment i.e also a big feature, and it adds tween the two pieces is 2,000,000 divided to the appearance of your set. 981, or 2024 grams, o; about 4.4 lbs. B Battery Potentiometer complete$1.00 Q. 2. How can it be shown that the lines Less Lever and Knob .50 of force tend to become as short as pos- Filament Rheostat complete 1.50 Less Lever and Knob 1.00 sible? B Battery Potentiometer Unit Lever and Knob .50 Knob and Lever A. 2. This is illustrated by the well -known phenomenon of attraction as when a mag- READY FOR DELIVERY net attracts its keeper. Familiar examples are the telegraph sounder and the electric OUR NEW COMPOSITION RHEOSTAT gives you the filament con- bell. trol for vacuum detectors you need. Write for description. TELEGRAPH LINE QUERIES. Guaranteed Satisfaction (731.) L. Kandiel, East Pittsburgh, Pa.,. wishes to know: Audio Tron Sales Co. 315 Lick Bldg., San Francisco, Cal. Q. 1. What is meant by quadruplex teleg- raphy and for what purpose is it used? M 511111111111111111111111111111111111111111111111111111111111111111 d A. 1. The quadruplex system as used to- day provides for the simultaneous trans- mission of two groups of signals in one direction and two groups of signals in the UNIVERSAL ELECTRIC MOTORS opposite direction, without interferehce and OPERATING ON A. C. OR D. C. -110 TO 130 VOLTS over a single telegraph line. Q. 2. is a simple duplex telegraph 1 /40 TO 1/4 H. P. CATALOGUE FREE How line connected so as to enable one to send simultaneously over the same line without THIS MOTOR $6.00 interference? 1 /1 6 H. P. R. P. M. 2. gives the -6000 Complete with A. The diagram herewith Pulley connections of a simple differential duplex TYPE AK Being Used Successfully for Grinding, Polishing Driving Small Machinery, Sewing Machines, Fars. Etc. Emery Wheel telegraph line. It consists essentially of Buffing Wheel a wound relay in each station $6.00 A MOTOR OF UNIVERSAL APPLICATION Chucks differentially Base Pulley and Chucks Easily Detachable Cord and Plug and connected as shown. The resistances R, at each station, are of such magnitude IF YOUR DEALER CANNOT CO. that they are equal to the resistance of the SUPPLY YOU. ORDER RACINE ELECTRIC SALES line. This resistance is called the arti- FROM US DIRECT. 304 South Dearborn Street CHICAGO, ILL. ficial line of the circuit : it is usually shunt-

Von benefit by mentioning "The Electrical Experi,nsntce" when writi, g to advertisers.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 845 ed with a condenser of proper capacity. Q. 3. Is it possible to determine the max- imum working distance with the simple telegraph system provided the various fac- tors of the system are known? A. 3. Yes; it is possible to determine the through maximum working distance that one can use the line. The following algebraic ex- pression will answer your question : ew..,,,,d 1 =R1- -2 Rs] tri Where: 1= maximum distance in miles that you The work of the can transmit world today is done by R= resistance of the line including the ground return electricity. Electricity E= voltage runs our machines; trans- I= minimum current required to actuate the recording instrument ports our goods; lights our 2Rs= resistance of the recording instru- homes, shops and factories; heats ment our buildings -is indispensable in (The factor 2 is used as there are two hundreds of ways. Opportunities in instruments used in the circuit.) electricity are greater than ever before. Exact electrical knowledge means moremoney and greater success for you. HAWKINS ELECTRICAL GUIDES give you ALL the electrical information you want, in the shortest, most concise form- I name,lyillustrationsmeans by of questions and an s wers and un- I It Ij limited. , No matter how great or how little your previous knowledge of the subject at 1 hand, you "get the point" at once in Hawkins Electrical Guides. They are absolutely complete- brought right up-to-date -the last volumes are just off the press. Connection for Simple Differential "Duplex" Telegraph Line, Utilizing Differentially Wound 3,500 Pages Relays at Each Station. .. 4,700 Illustrations ,-net t¡It. I,Ñmy lout tl;,r. Iaup' Aunt limb lent Tamf law t:,DS a.,,, t' CHANGING MOTOR RESISTANCE. lupn+ Dsurt haecr INdpud úhrç ivitt Wp4l 310111e, peat Alma all/f_ f'la 4IX 4n+ GEa pill en, Gies A I (732.) F. Jewett, Savannah, Ga., asks: es :'GUIDS ¡p t1 y'8i Q. 1. Is it possible to change the resist- $1 A Volume ry,.wP AeeT ',Pa., !M6 d9' Via. 1 ance : of an armature? ca..., V I r A. 1. Only by rewinding it. It should be $1 A Month °v remembere3, however, that = part of the re- , / sistance of the armature circuit is at the ®.'® ®.I®('® '® ® A _41, contact between brushes and corn- mutator. Therefore, a motor with an un- clean or uneven commutator, loose brushes PARTIAL CONTENTS OF THE 10 GUIDES 10 Practical Volumes- Flexible t Electrical nra .ods boL,,nae,scrr.ntdu,e to" y, -. or poor connections will not run at so uni- p cel,Mati and ulaton rm pd n d Leather Pocket Size r etem, inErm, ead. d,T.mo intuitingc, dames a.et Binding- form a speed as when put in first class run- ;: , . ANmatun,, n , nmmut.tion , brushes, motor They are the handiest books to read and to use, ning order. Any excessive heat around the sip, armature g.ealewaoov.br.< ' power, unction ëdiaa e dynamos pd motn e. ever produced. In flexible, black covers, leather brushes or holders should be in- It 3. cal.pemewn, npdmd tels, e therefore tat.volam wattmeters, wattbátemói binding -just the right size -Sa6!4 inches -to fit in your vestigated. é ' n 4 pum° üiewat w i a , pocket, so that you can carry each single volume about Q. 2. How does a u.,áwintr aad swing. eathñ , hghtomi wn change in the field re- Poo. t fien, normatteynemam ett with you until you have mastered its contents. The whole sistance affect the torque a on g Altermupg prinapb dteme' n dr set fits easily in the hollow of your arm, and still there are of motor pw ,heT n hnn, t

www.americanradiohistory.com 846 THE ELECTRICAL EXPERIMENTER March, 1917

Q. 2. What do you consider the best ma- terial for building a potentiometer for this MIGNON UNDAMPED WAVE kind of work? A. 2. The simplest method of making r,0. such an instrument is by winding German elk Silver wire upon an insulated form. This it WIRELESS wire should be wound non -inductively, and it can be done by doubling the wire and winding both of them on the insulating form. F r APPARATUS Q. 3. What do you consider best for selective tuning of either of the following `J...R .t. J=-..a7 Amateur and Commercial Use instruments, namely, The Electro Import- ing Co.'s vario- selective coupler or an or- dinary loose coupler outfit? This latest Mignon invention is entering a new A. 3. As far as selectivity is concerned, we believe that the vario- selective coupler field in Radio Engineering, eliminating the so is better and more efficient than an ordi- nary loose system. familiar LOOSE COUPLERS and LOAD- coupler RADIO QUERIES. ING COILS, and introduces adjustable DISC - (734.) J. Lamat, Long Island City, L.I., asks: CORES, heretofore considered impossible. Q. 1. What is the wave length of my an- tenna, which consists of four wires each DISTANCE RANGE UNLIMITED. 100 feet long and 80 feet high? A. 1. The maximum natural wave length of your antenna is 340 meters. Q. 2. How can I reduce this wave length Mignon Wireless Corporation so as to comply with the Government re- ELMIRA, N. Y., U. S. A. zRka°NÓIÓ quirements? s A. 2. By connecting a condenser in series Write for Catalogue and mention Electrical Experimenter with the ground. Q. 3. What type of antenna do you con- sider best for transmission work? A. 3. The "T" type antenna is best suited for general transmitting work. AdirA, INDUCTANCE. i (735.) Charles Mantel, New York City, ir N.Y., wants to know: Q. 1. How does inductance cause the cur- rent to lag behind the voltage? A. 1. It tends to prevent changes in the strength of the current. When two parts of a circuit are near .ach other, so that RADIO RECEIVING PHONES one is in the magnetic field of the other. any change in the strength of the current Read what Experienced causes a corresponding change in the mag- netic field and sets up a reverse pressure in Operators say about them the other wire. This induced pressure and remember -we guarantee every set. causes the current to reach its maximum Money back if you are not satisfied. value a little later than the pressure, and also tends to prevent the current diminish- "Have compared H -C phones "We received undamped sig- C have used your Light Weight ing in step with the pressure. with other makes costing from nals from Nauen, Germany, Radio Receivers continually dur- Q. 2. Why is capacity reactance given a $5 to $20. The conditions which is outside of Berlin. We ing the past two years, for the negative sign? during the tests could hardly merely used large undamped reason they have given entire sat- A. 2. Because it reacts in opposition to coupler which would tune up inductance; is, it to reduce the have been more varied, rang- isfaction and are very efficient in that tends to 15,000 meters, three vari- spurious resistance due to inductance. In ing as they did from cold, clear "pulling in weak signals. able condensers and audion circuits having both inductance and capaci- atmosphere of winter to static detector. While on the Mexican Border ty. the tangent of the angle of lag or lead charged month of July. With- Holtzer -Cabot Phones were with the Massachussetts Signal as the case may be is the algebraic sum of out exception H -C Phones used, without any amplifying Corps we used these telephones the two reactances divided by the resist- have proven their superiority" device." and the results were remarkable." ance. If the sign be positive, it is the an- gle of lag; if negative, it is the angle of Send for Booklet lead. 1687X Ì h e Holtzer-Cabot Elec. Co. CHICAGO FLASHER. (736.) Paul.Andrews, Greenpoint, N.Y., asks: Q. 1. Upon what principle does the ther- EUROPEAN STATIONS MONOTONE m° flasher operate? IIAVE BEEN RECEIVED WITH THE IMPROVED QUENCHED GAP N. 1. This type of flasher works on the PHONES ON THE TABLE, using our copy- thermal or heat expansion principle; that righted circuits and directions for securing the is, movement contact points of best results from a single bulb or tubular detector. the of the Circuits for the regenerative, osculating and am- the flasher necessary to open and close the plifying audion. Short and long waves Amplifying circuit, is obtained automatically by the al- powers with single audion up to one thousand a metal times. No instruments not found in the usual ternate heating and cooling of bar amateur station required. A thousand miles may in the flasher, which causes it to expand be covered using only a small indoor aerial. Are you a leader or follower n adopting up- to-the- and contract. Germany has been repeatedly received on an 85 minute efficient apparatus Equip your station witb 2. foot aerial using these circuits. thousand the famous MONOTONE IN PROVED QUENCH- Q. What should be done with the old Eight ED GAPS, which are a big mprovement over the miles common with long aerial. Circuit for using original MONOTONE GAP Span that freak dis- electrolyte of a storage battery? audion in experimental Wireless Telephone trans- tance on powerful waves of RADIO ENERGY. Each A. 2. When a battery is taken down, the mitter, no arc being required. Circuit for ampli- plate carefully machined. Best mica. Adjustable. fying signals from Audio-Rotor or tikker through One unit of the new gap for spark coils up to 3 ". One electrolyte may be saved and used when audion. Series of 12 blue prints with notes copy- unit for every if K.W. power of transformer. Spe- reassembling the battery, providing great righted cially recommended for powers below if K.W. Parts 1916, printed with your name, postpaid pickled and polished. You will be pleased with this care be exercised when pouring it out of the 50 cents, stamps or preferably silver. new gap. Guaranteed. Postpaid $2.50 Each. ijar, so as not to draw off with it any of THE RICHARDSON CO., Manufacturers of Radio Apparatus ERIE, PA. the sediment. It should be stored in con- venient receptacles, preferably glass or earthenware carboys, which have been You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 847

thoroly washt and never used for any Dynamo other purpose. EDUCATIONAL INSTITUTIONS. tltirIlótpI6ltlrlly Motor (737.) C. Bernhardt, Brooklyn, N.Y., For Boys wishes to know: 25 Q. 1. Where can I take a night course For producing current for in- in Electrical Engineering somewhere in ductance coils, re- charging Brooklyn? storage batteries, elec- A. 1. There are two educational insti- troplating and hun- tutions in Brooklyn where you may learn dreds of other uses. Electrical Engineering, namely the Pratt In- Well constructed stitute and the Polytechnic Institute. The throughout, exception- former school offers a two -year course, The Most Modern ally smooth running which is of a practical nature and does not and highly efficient. A give any degree, while the latter is a Col- good, strong, durable lege of Engineering and its courses during Circuit for dynamo. the day are of four years' duration at the AT ALL LIVE DEALERS end of which time the student is given a Insist on your dealer showing you the KNAPPI Ire- - degree in Electrical Engineering when he Wireless Stations KNAPP goods are best. It your dealer cannot supply has completed his course. you, order direct. Send for FREE illustrated eatx- logue showing a complete lino of Electrical Motors Q. 2. How can I obtain information as to Are you familiar with the efficiency of and Novoltics ranging in price from l0c to SIP. the studies given at Yale University, Wor- this new circuit? KNAPP ELECTRIC & NOVELTY CO. cester Polytechnic Institute, Boston Poly- Do you know of the progress made dur- 523 West 51st Street, N. Y. City technic Institute and Harvard University? ing the last year in wireless telegraphy? A. 2. Relative to school addresses would Everything about electricity-and wire- advise that you communicate your inquiries less telegraphy -is told in the brand new regarding studies, etc., at Yale University Cyclopedia of Applied Electricity. ENCLOSED to the Registrar, Yale University, New Ha- ven, Conn.; the Registrar of Worcester ROTARY GAP Polytechnic Institute, Worcester, Mass.; AllAbout Electricity Registrar of Boston Polytechnic Institute, In these seven handsome is This gap has been designed volumes contained all to Boston, Mass.; Registrar Harvard the knowledge about electricity that 27 experts have to sell at a low price and Univer- gained meet the demands of ama- after years of labor. They are not hand - sity, Cambridge, Mass. l.00ks -buta complete encyclopedia. Theelements teurs for a good, enclosed of electricity; and silent gap. Finished in electrical measurements; generators and motors; machinery; are all explained and dull black, it will add to the RANGE OF INSTRUMENTS. carefully appearance of your set. diagramed in this remarkable set of books. (738.) J. C. O'Donnell, N.S., Pittsburgh. This new edition contains 3,200 pages and 3,000 It is made in one styleonly, illustrations, full -page plates. diagrams, etc. Bound for all powers up to I -KW. Pa., desires: in half -red morocco, stamped with gold. and can be mounted in al- Q. 1. The length a most any position. wave of three-wire The gap is enclosed in a aerial two hundred feet long and fifty feet circular iron housing 8 inches high. 50 Cents a Week We in diameter and 2/ inches A. 1. This aerial has a natural wave will ship you the entire seven volumes pre- thick, with removable cover paid, for 7 days free trial merely upon receipt of (for inspection). The adjust- length of 400 meters. the coupon below. Then, if you wish to keep it. ment can be as close as desired Q. 2. The probable range of the follow- pay only $2 after the trial and $2 a month (50e. a between sparking points. ing set with the above aerial; two thou- week) until $19.80 has been paid. This is a special bargain price offered for a limited time. Rotating disc is of brass with 12 projecting sand meter loose coupler, variable and fixt round brass arms (total diameter 6 inches), The regular price is $35.00. mounted on shaft running in bronze bearing condenser, silicon detector and two thou- and is belt driven by small motor giving a sand ohm 'phones. 7 Days' Trial variety of tones depending upon the speed, A. 2. You should have no trouble in re- Useitjust asif it were your this gap is very quiet own for When in operation ceiving 1200 to 1500 miles with your in- 7 days; then decide Price complete, without motor, $8.50 struments. whether or not you I. Herbert Ferris, 211 Catalpa Drive, Royal Oak, Mich. Q. 3. Could NAA (Arlington) be re- want to keep the books. This offer ceived with an eighty -foot aerial and two is made to everyone thousand five hundred meter loose within the bounda- STATION- - coupler? AN EXCEPTIONAL A. 3. Yes; providing a proper capacity ries of the U.S. and Canada. At an Exceptionally Low Price variable condenser is shunted across the N. A. A. time signals as well as all stations instantly be attuned to without "detector fussing." Our TEL-HAUION Is in- secondary of the loose coupler. cluded in this station thus eliminating all detec tors and trouble. Consulting Receiving capacity of this station is thousands of miles with. fairly good capacity aerial. Will tune up to .1.000 meters. An ideal Service Free outfit capable of receiving all the commercial stations m time signals. VOICE -OPERATED TYPEWRITER. A year's consult- as the following instruments mounted in a birth Thwellis station includes ing membership Oblast highly fimsheo ip moho y, (739.) The A. T. Co., New York City. loaringco,I NATION TYPE E TUNER a e enseriof (regular price. $12.) TEy peruser loading coil, Fina metres.de ser. Bra of wish information on the voice -operated will be gi ven free i f you send your order at once. 49 le orzad ce cont TEL-RADIONtBAmON witch ant Wireless MCrys whichten oho the duplex cif is,snd typewriter described in the April, 1916, issue our No.CroCn +tar Detector. switchanmpro- to to protect the detectors Ironfrom burnoutburnouts if a transmitting Of THE ELECTRICAL EXPERIDI ENTER. station Is employed. Send the Coupon! Complete as described, $23,50 A. 1. We would advise that the Phono- Put your name and address in the coupon now With a p air 2000 ohm Brandes headset scribe as developed by Mr. Flowers is not and send it to us. You won't be under any obliga- $28.01) compl ete with aerial on the market. tion to buy if you ask us to send you the books on suiators g ground trial. Send the coupon now. wire. ale adi The article as publisht in this magazine gne ouproadf r hadsiet , was finisht to commercial completion, so to $13.50. speak, by our editorial staff. However, Mr. American Technical Society Flowers has exercised wonderful ingenuity Dept. E.9443 CHICAGO, U. S. A. in devising special arrangements for the operation of such a voice scriber, and, quite possibly, in the reasonably near fu- American Technical Society Dept. E 9443 Chicago, U. S. A. ture, you may be able to purchase such a machine on the open market. Please send me the seven volume set of the Cyclopedia of Applied Electricityfor seven days' If you wish to inquire into this matter free examination. If I decide to buy. I will send further, you may communicate with Mr. you $2.00 In seven days and balance at $2.00 a Flowers, addressing him in care of the month until $19.80 has been paid. Then you will I TEL - send me a receipt showing that the set of books RADION CO. American Institute of Electrical Engineers, and the $12 consulting membership are mine and 37 West Thirty -ninth Street, New York. fully paid for. If I think that I can get along without the books. I will return them after 7 days Alternators! at your expense. Generators! AUTOMOBILE HOIST IN WIRE- We have a complete line of sturdy, efficient gen- erators and alternators from 100 to 1000 watts. LESS WORK. Name We furnish complete parts for these finished ready Workmen on the masts of the Marconi to assemble with instructions to wind. Trans- formers made to order. Send for catalogue. station at Bolinas, Cal., were raised aloft A ddress ALL AT FACTORY PRICES by means of tackle connected to a touring car, the car engine Bergmann Motor Works, 442.446 Niagara St., Buffalo, N.Y. supplying the hoisting L Reference power. You benefit by ,mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com 848 THE ELECTRICAL EXPERIMENTER March, ;917 THE WASHINGTON'S BIRTHDAY RELAY, FEB. 24, 1917. (Continued front page 805) VIOLET- RAYS! being temporarily out of service. Now all of you wanted something hard, so go to NEW LIFE, POWER, HEALTH and BEAUTY in it and get the M.S.G. from New York and the marvelous delightful VIOLET -RAYS. also get the one coming from Los Angeles, Newest Cal., as soon as you get these M.S.G.s de- and most powerful form of electricity, causing neither liver them to the mayor or highest civil muscular contraction nor pain of any kind. authority in your city and get his receipt and mail them at once to 9XE, Davenport, THE VIOLETTA Ia., no name, just "9XE" that's all, so that I may get to work again and work I Li._ea:\ High frequency instrument is endorsed by thousands of Physi- all night on the write -up, in order that you cians who use it daily. may read it in your magazine. If you Produces SOOTHING, INVIGORATING, CURA- want the wave length of the various send- TIVE VIOLET -RAYS. Wonderfully quick results ing stations look in the Government call- obtained in treating SCALP, FACE and BODY. book ; only the sending stations will be Health bringing OZONE forced into the blood, pro- given this information, as each will receive ducing an abundance of VITALITY. a personal letter from the writer in good Sent on Free Trial time before the relay. Now you all wisht Simple in construction and operation. The VIOLETTA this hard work on yourself so it is now up is especially adapted for personal use in the home. to you; the results of the relay depend Will operate on alternating or direct current or battery. upon those who do not send, those keep- ABSOLUTELY SAFE and GUARANTEED. ing quiet and those asked to send to keep Write for New Free Book quiet after getting Q.S.L. Send for our new beautifully illustrated book on VIOLETTA. We are anxious to get the M.S.G. from Tells all about the marvels of Violet -Rays. Read what scien- both coasts to New Orleans and believe tists and doctors have to say. Post card brings book and all we must use the following route: 6EA, particulars of special low price and free trial offer. with 6DM and 6SH, alternates if needed, Dealers BLEADON -DUNN CO. DePt. 9ZF, SDU, Emerson, Dallas, Texas, 9ABD, 208 NORTH FIFTH AVENUE, CHICAGO Corwin, Jefferson City, Mo., 9GY, Kern, Matoon, Ill., 8AEZ, west, Lima, Ohio, 2AGJ, Hewitt, Albany, N.Y., and lIZ, our old "bright star in the East," Robert T. St. James, who must get it back to New New Undamped Wave Coupler No. 749 York City mayor thru a local station. Special Introductory Price, $18.00 5ZQ, St. Charles College, Grand -Coteau, La., and 5ZD, C. B. De La Hunt, Mem- Our new coupler No. 749 Ls 32'' long, 9" wide. and 10" high, over all, and on an average -sized Antenna phis, Tenn., have agreed to help getting the tunes to 15.000 meters. This coupler. used with the M.S.G. to SZS, W. Anthony, Shreveport, new CHAMBERS' SYSTEM or CIR- CUIT, will bong in signals from domestic La., if he does not get it direct from 9ZS and Medan Arc Stations surprisInglY loud and clear. Note the difference In or 9XV or 5ZC on the way west, but they size of our No. 748 and No 749. are asked not to send if 5ZS- Q.S.I.'s We claim to be the original Inventors of a SYSTEM or CIRCUIT for the recep- promptly, or they will QRM route west at tion of the undamped waves without the 9ZF. use of Loading Coils or Oscillating Coils. as they arereCIRC called: s Inducltivour Mr. and Mrs. C. Candler are requested SYSTEM CIRCUIT Coupled Coils are necessary. Circuit supplied to get M.S.G. going west from N.Y. and each This AMBERS' CIRCUIT saves You money. send it on 200 meter wave on a Q.S.T., Think of it! No extra coils to pay for, sad price of coupler only $18.00. Place order m to be in on the introductory price. orders filled in rotation. Send for three times after M.S.G. leaves 9ZN and descriptivede. crip matter. 5ZC, going west; this is for the benefit of F. B. CHAMBERS & CO., 2046 Arch St., Phila., Pa. all the southeast stations from Baltimore to Florida, as they will be listening for SNH. They will also give return M.S.G. from west on a Q.S.T. three times for the benefit of the same stations, but 8NH will Use Bunnell Apparatus not send this M.S.G. on its return from Best and 6EA until lIZ acknowledges Q.S.L. Sta- mostdur- tion KIX, Denver, and KIW, Mr. Colburn, able. Up -to- Ajax mines, Victor, Colo., will be on the date dealers job to help us out at this point, which is have them a hummer and has caused the writer many tp in stock. gray hairs. Among the many special sta- Our Catalog tions agreeing to help are Cornell Univer- í11 36E illustrates sity, University of Pittsburgh, Ohio State and describes No. 8654 Dandy 21 Plate Variable University, Illionis Watch Co., thru our old about 300 ar- Condenser $3.90 ticles of wire- friend 9ZS, Mr. G. S. Johnson ; State Uni- apparatus versity of Iowa, Iowa City; Professor asw as other J. H. BUNNELL CO.'S 8804 Detector Ford, University of North Dakota, Grand No. Jove Crystal Holder appliances. Radio Dept. On Dark Porcelain Bee . $1.20 Send 2c stamp P Forks; Professor Taylor, Washington Uni- 32 Place New York On Handsome Composition Base . . . 1.50 for it. to Park versity, St. Louis; Professor Blatterman, to whom with Professor Taylor, we are all indebted for our real information on long Wireless distance sending. Rev. Fr. Phillippe, St. Charles College, La.; Rev. Ruth, St. Mar- tins College, and our old friends, Mathews, Transformers in Chicago, who is now in charge of Spe- cial station 9ZN, formerly 9IK, Corlett Best For Long Distance Work 5ZC, Dallas, Texas, who says there are 1 only four states in the country that have Every user reports exceptional range with heard my "sigs," and the other well - these instruments and loud messages are se- not cured every time. known boys who have worked hard at the Many amateurs buy one of these unmounted game and on whom will fall the burden and build their own transformers at low cost. of putting this M.S.G. thru. Don't forget boys, we are working against time; so cut Write for details and stations Wireless Bulletin T207 out QRM as the special are go- ing to try and make better time than the amateurs in these messages, and truthfully WARREN I want the amateurs to lick them to a n :ai' fWivsipfanx OHIO splinter. Write 9XE about any Q.R.M. You benefit by mentioning "The Electrical Experimenter" when wríti, g to advertisers.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 849

whether from commercial or Government stations. None of the operators at these stations were born with receivers on their ears; they all had to learn and plenty of them LAST have still more to learn; so wc'ltope they will not be so impatient on this night and try to hog the air. We hear Government stations every night hogging the air with CALL,! lots of fool stuff worse than amateurs and numerous commercials calling each other More names -we hear you boys, so have a heart Only a Few Left and give us a real chance to make good- so we may be able to work with you later and not against you. The writer's expe- The greatest bargain rience in the U.S. Navy taught him that there are many points of etiquette yet to be ever offered in elec- acquired by the commercial class as a body, trical literature. but you are all good scouts, so help us out just a little for the "love of mike," and give us just a few minutes out of the 525; A complete volume 600 minutes in the year to try out our Big Money in of schemes. the Electrical PRIZES. Electricity Experimenter The Thordarson Co., of Chicago, Ill., The Electrical industries offer have donated again a 1K.W. transformer, bound in rich, dark which you almost won on the Presidential wonderful opportunities to boys with green linen, stamped Relay, November 27, 1916. The Electro a liking for Electricity. The salaries Importing Co., of New York City, have paid to trained men are large, pro- with gold letters at very kindly donated one of their "Nauen- POZ" Radio Receiving Sets (first prize) motion comes rapidly and, best of all, the extraordinary low and one of their "Professional" \Vave Met- the work is fascinating. price of ers (seeond prize). The W. B. Duck Co., of Toledo, Ohio, have donated one of their The discovery and development celebrated "Arlington" tuners. The Mesco of new lines (such as wireless teleg- Co., Chicago, Ill., thru their Mr. McGivern, raphy and telephony), from time to $1.25 time, promise attractive and paying DO YOU fields to those who wish to special- own a wireless station, either for sending If you do, ize. The will to do and Special 7 is or receiving? Postage on lbs. extra don't fail to join the greatest Wire- Training will bring success to you. less Association in the country: THE RADIO LEAGUE OF AMERICA. If you believe in the The International Correspond- preparedness of your country, if you ence Schools can help you to be- wish to help Uncle Sam. if you wish to have your station officially recognized. join the LEAGUE, a national, come an expert in electrical work, non-money -making organization. Beautiful engraved and sealed certificate. FREE to all members. NO no matter what branch you like 'DUES OR FEES WHATSOEVER. best. Thousands of young men have W. G. BUL- Honorary Members: H. already won through I. C. S. LARD, U. S. N.; PROF. REGINALD A. success FESSENDEN; DR. LEE DE FOREST; help. You can do as well as any- DR. NICOLA TESLA. body, ifyou try. Everything is made e Send stamp for large 8-page information booklet. so clear that you can learn in your DO IT NOW. 233 Fulton St., New York City, N. Y. spare time, regardless of where you live or what your work. No books donated a pair of their 3,000 ohm Mesco to buy. 'phones. The F. B. Chambers Co., of Philadelphia, Pa., will give a prize and it There's big Money in Electricity. will be one of their No. 748 or 749 Tuners. Get after it by marking and mailing The Adams -Morgan Co., Upper Montclair, Coupon today. Finding out costs N.J., will also donate something worth the your while and a number of other manu- you nothing. facturers have agreed to give plenty of MARK THE COUPON NOW Volume contains twelve numbers, 743 things. The full list of prizes will be pub - ages, 1,226 complete articles, 1,742 lisht in the April issue of "EE" and the TEAR OUT HERE "- illustrations, 227 questions and answers. disposition of them will be determined INTERNATIONAL CORRESPONDENCE SCHOOLS after consulting the donees and the ama- Box 5337, SCRANTON, PA. A world of electrical information; teurs of the country after the Relay. Explain, without obligating me, how I can quality for the entire electrical Progress for one Don't forget the final reckoning will be the position before which 1 mark X. ELECTRICAL ENGINEER Commercial Law year; the greatest reference book on made after this Relay and the number of Electrician CHEMICAL ENGINEER current "Wireless " at a price as Telegraph Expert SALESMANSHIP -all credits you receive will determine along Practical Telephony ADVERTISING MAN low as the unbound copies would with the number received on the last Relay Electric Wiring Window Trimmer is Electric Lighting Show Card Writer bring. Mind you, the book durably as to who gets the best prize of all. Electric Railways Outdoor Sign Painter bound with heavy covers. You will Letters with receipts of M.S.G. and re- Electric Designer RAILROADER MECHANICAL ENGINEER ILLUSTRATOR be proud to have it in your library. ports with post -marks on the letters. show- Mechanical Draftsman ARCHITECT We have only 100 copies, therefore be Go Engineer Areblteeteral Brahma. ing they have been mailed more than forty- CIVIL ENGINEER GOOD ENGLISH sure and order today. Shipping weight eight hours after midnight, February 25, Surveyingand Mapping Teachers Course 7 lbs. Add sufficient for Metallurgist Comment Nehool Sobjeata a amount 1917, cannot be entered in the final round- STATIONARY ENGINEER CIVIL SERVICE postage. up Concrete Engineer Railway Mail Clerk for the write -up so please get busy at Structural Engineer AGRICULTURE Order today to avoid disappointment once boys and send your dope in at once, BOOKKEEPING Navigator Q German i.e., Stenographer and Typist Poultry rrmas right after the Relay. Cert. Pub. Accountant ATOMOAUTOMOBILE.' Italian We received so many requests to have Railway Accountant Auto Ilenatrivg Italian EXPERIMENTER PUBLISHING the Relay on Saturday, February twenty - Name COMPANY, Inc. fourth, that we decided to hold it at that Occupation, if any, time if hitch in getting and Employer and any comes the Street Sooft Department, M.S.G. west or east we will start the same and No 233 Fulton Street, New York, N. Y: time Sunday night, the twenty -fifth, and City State do it again. Another all over thing, if the of Course Want la not In thla flat, write It below. cast bound M.S.G. gives any trouble corn- Hearne you You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com 85o THE ELECTRICAL EXPERIMENTER March, 1917

ing from Los Angeles, 6DA, we can have AskYour Dealer the chance of our lives for a little early morning work and still be in time for church. As a last call boys, do your very best to keep your sets quiet during the Re- lay-I know it is a tough job to listen and to show You hear not -I have been there -but try it just once; take out your fuses and resolve for this one night you will not arbitrarily spoil the work of thousands by a few Mo- these Handylight ments' unnecessary sending. Now I have done my part and the rest is really up to you -go to it and luck to you. Cordially yours, 9XE, They Are Davenport, Ia. The following stations are appointed Mighty Useful "monitors of the ether" and will report any Q.R.M. from amateur, special, commercial in or government stations; even the Allies For finding your way the dark; for signalling are requested to keep quiet for a few mo- at night; for the thousand and one times when ments!! C. F. Ouidin, 2AFT, Schenectady, N.Y. you use matches to light your path, use a safe, Graceland College, 9Y0, Lamoni, Ia. sure The Old War Horse, 9RD, Clinton, Ia. O. R. Terry, 9I1Q, Stoughton, Wis. MacQuarrie, 6SII, Stockton, Cal. H. P. Maxim, 1Z.M, Hartford, Conn. Franco Flashlight \V. A. Parks, 3ZW, Washington, D.C. Lieutenant for, lIZ, Massachusetts. D. R. Simmons, 5AX, Shreveport, La. D. H. O'Neill, 9DÍ , St. Louis, elo. They are made in a variety of sizes -one is bound to suit Mr. and Mrs. Candler, 8NH, St. Mary's, you. With a Radio Battery inside, they will give a brill- Ohio. iant light lasting a long time. Get one from your C. Dunning, 8YZ, Pittsburgh, Pa. white F. B. Chambers, 3XC, Philadelphia, Pa. dealer's today, or write for illustrated booklet. Il. Brownell, 5AM, Birmingham. Ala. W. T. Gravely, 3RO, Danville, Va. INTERSTATE ELECTRIC NOVELTY CO. W. S. Rothrock, 4DI, Winston- Salem, N.C. 104 -114 S. 4th STREET, BROOKLYN A. A. Herbert, District Manager, A.R.R.L., CHICAGO .. SAN FRANCISCO .. TORONTO New Jersey. F. F. Merriam, 4CL, Atlanta, Ga. S. Greenleaf, 9ZG, Woodstock, Ill. W. Reinhart, 9BW, Omaha, Neb. W. S. Ezell, 9YE, Wichita, Kans. Cedric E. Hart, 6SL, Salt Lake City, Utah. An Opportunity for Experimenters THE CALCULATION AND MEAS- to secure a GOOD storage battery at 1/j UREMENT OF INDUCTANCE. a moderately LOW cost. The (Continued from tage 813) ONE article you cannot Substituting the values for F' F" in equa- TVA tions (8) and (9) we obtain for F' (1.12) afford to i storage batteries are es- and F" (1.03995). ..olving the above we e Marko'Quality with peciallyj adapted for operation of ment obtain for L= .000198 henry or 198,050 cen- all kinds of spark coils, insuring a heavy timeters of inductance. is a storage nothing superior and powerful spark. There is It will be observed that the shape cor- battery. FOR AUDION USE rection It Pe Volts Lisp. 11.0 Lint Special price to factors are very small and the larger Capacity40 wirelessw .20 iseor s the coil 9(2 4 8 17 00 becomes the nearer will they ap- 6C2 6 40 1000 6.00 proach unity; for this reason they may 6(4 6 60 12.00 7.20 be 6C6 6 80 16.00 9.60 neglected for coils whose diameters are one -tenth PAUL M. MARKO, 1191 Bedford Ave., Brooklyn, N.Y. New York Depot -974 8th Ave., New York City that of their length. For long inductances, such as those used in the regenerative Audion circuits for re- ceiving undamped waves, the above formula is particularly useful. As an example, the inductance of a long wave loading coil, con- NEW "TUNGAR" RECTIFIER No.995 sisting of a single layer of No. 28 S.S.C. magnet wire, wound on a cardboard tube This is one of the latest developments of 28 inches long (26 inches of winding) and the GENERAL ELECTRIC CO., and is 558 inches outside diameter was ascertained of the hot cathode, argon gas filled type, to be 76,355,400 cms. Using this coil in acting independent of frequency. series as a loader, with a 4 wire, 500 ft. flat -top, inverted "L" antenna, 100 ft. high, Made in three sizes and with a loose coupler primary having 9,400,000 cms. of inductance, the wave length capacity figures out to about 22,900 MAGUIRE & SHOTTON meters; sufficient for practically all ex- perimental requirements. Special Circular upon request ALBANY NEW YORK The formule given herein for calculat- ing the inductance of coils is for the cur- rent -sheet value, and apply accurately only to a winding or infinitely thin For the electrical metal strip, experimenter's repair kit which completely covers the solenoid, the successive turns being supposed to meet at "Red Devil" Combination Plier the edges without making A 51¡-Inch drop forced steel tool combining burner grip. flat, electrical contact, nose and side cutting plies. Scientific handles fit hand and and so realizing a uniform distribution of prevent slipping. From dealers, or it not, from us for 70c. Style No. 325 /a. current over the surface. If we have a Tool literature sent free on request winding of insulated wire or of bare wire 107 Chambers Street Smith & Hemenway Co., Inc.,Inc. New York City wound in a screw thread, we may have (Continued on page 854) You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 85 i

THE U.S. NAVAL OBSERVATORY. TRAVELING AT 500 MILES PER HIGH - HOUR IN THE FUTURE With increased and increasing speed of WITTE GRADE ENGINES fighting ranges, ELECTRIC RAILWAY. our warships, increased Kerosene, Gasoline, Gas, Distillate. and the continuing development of sub- (Continued from page 794) marines and aircraft has conic thc neces- means of of powerful electric solenoids placed 2to22H -P. sity for new and more rapid methods along the track, as shown in the accompa- VFor which Naval Q. operating belted machinery, elevators, navigation and plotting, the nying plan view. The details of switching, pumps, bone mills, feed grinders. cream Observatory has met by encouraging sug- etc., are not given, as there are several dif- separators, crushers. mills. blowers, hoists, gestions, aiding in the development of ferent ways in which this could be taken etc.- Stationary or Portable. also Saw- instruments, making trial of Rigs, complete. Largest exclusive engine methods and care of, but in some of the schemes de- ED. H. WITTE factory in the world selling direct to the all such as give promise of usefulness and veloped in this direction, the opening and user. Saves $25 to 5100- Immediate Shipment - furnishing to the service those that have Write for latest WITTE prices ['a closing of the solenoid circuits as the car and catalog of engines. State proved of value. progresses on its way, is functioned or size wanted or what work you r* ._ The usefulness to navigation and to the cared for by the movement of the car it- have.-Eo. H. Wirre, l're,., country in general of the daily time self. In other words the car, as it moves WITTE ENGINE WORKS ``-' service has been added to by the installa- along, passes over a set of electrical con- , up -to -date transmitting clocks 3937 Oakland Avenue - Kansas City, Mo. tion of two tacts placed between solenoid points, so that 3937 Empire Building, - Pittsburoh, Pa. and arrangements for checking the actual the solenoid is deenergized just as the car emission of the radio time signals, which approaches it; the momentum of the car are now received thruout the country east carrying it forward owing to the powerful I4,_,.P. of the Rocky Mountains and the contigu- magnetic pull of the solenoid which had 4 _AGE S ous oceans for several thousand miles, ac- acted on the car a brief instant before. This 'ILLUSTRATIONS cording to the report of the Secretary of is the principle upon which electromag- I.C.S. the Navy. The time for the country west netic guns operate also. of the Rocky Mountains and for vessels ELECTRICAL ENGINEERS There is still another way to reduce the HANDBOOK navigating the north and east Pacific initial installation expense of such a rail- LC S 50` Ocean is sent out from the navy chrono- way system, by placing the locomotion coils meter and time station at the Mare Island or electro- magnets within the car, or rath- k$IDBOeK Navy Yard. er on the car; these moving solenoids to ELECTRICITY! The routine astronomical work of the act on iron rings or armatures of suitable just the book on observatory for keeping track of the cross -section placed along the track The HERE'SElectricity that you need heavenly bodies has been kept up, a photo- current can be periodically switched on and to answer your many ques- graphic zenith tube telescope for determ- off automatically, so as to act in the manner Cscrmriu. tions-to solve your knotty above described, whereby the electromag- alótacrlü problems, to teach you new kinks, to ining the variation of latitude added to be your memory for tables, rules, the plant, and the photographic work ex- net coil would be deenergized just at the formulas and other Electrical and instant where the moving car is approach- Mechanical facts that some people try tended One volume of observations and carry in their heads -and fail. the Differ- ing the point of maximum magnetic pull. to an appendix, "Determination of With Giant" I. C. S. Elec- Washington In any event, this particular action sim- this "Little ence of Longitude between mers down to the point where what is re- trical Engineer's Handbook in your 1913-14," have been publisht. pocket, tool chest. on your work and Paris, quired is a powerful electro- magnetic pull bench, draw ing table ordesk an hour The 1916 Nautical Almanac contains im- between an iron mass and the electro -mag- or a day need not be lost ¡'digging and additions over previous up" some forgotten rule. some unfamiliar fact. provements net. you'll just turn to the very complete index and issues, and tables have been gotten out to This all sounds very simple, as well as get it in a jiffy." Just a few of the subjects add the times of sunrise and sunset and impracticable, but a system of this kind can treated are: moonrise and moonset in future editions. be worked out, and has been tried out, in Electricity and Magnetism; Electrical Symbols; Batteries; Circuits; Magnets; Direct and Al- For the ensuing year the Naval Observa- fact, in the laboratory by M. Bachelet and ternating Currents; Dynamos and Motors; tory will continue its routine work of other inventors, with track systems having Belts; Shafting; Electroplating; Electrical Almanacs, and a length of 1,700 feet and more. Measurements; Meters; Arc and Incandes- furnishing time, Nautical cent Lamps; Mercury Arc Rectifiers; Trans- navigational instruments; and it is hoped Such a high speed, tubular electric rail- formers; Insulation; Electric Cars; Single and will be allowed.a small appropriation for way system would have many advantages Multiple -Unit Control; Transmission ; Rail fitting out a party to ob- over present day methods of transporta- Welding; Tables of Wires -Sizes, Capacities, preparing and tion, and one of these is that the peculiar etc., -Mathematical Rules, Formulas, Sym- serve the total eclipse of the sun, of June bols; Tables of Constants, Equivalents, Roots. design of such a railway lends itself well Powers, Reciprocals, Areas, Weights and 8, 1918, the path of which will cross the to support on a single row of steel towers Measures; Chemistry; Properties of Metals; United States. in the manner shown on our front cover, Principles of Mechanics ; First Aid. etc. and the elimination of local stops. The Electrical Engineer's Handbook is one of 22 I. C. S. Handbooks covering 22 Technical, Scien- SHOOTING BIG GAME ON THE While the hypothesis and ideals of Pro- tific and Commercial subjects, all crowded with fessor Weinberg as previously outlined, not value. They have the contents of a full -size book ELECTRIC "MOVIE" TARGET. condensed into pocket -size ready to go with you (Continued from page to mention those of numerous other invent- anywhere and be at your instant command. 793) ors and scientists, have often been rudely They are substantially bound in cloth, red edges, by a separate spring in by goldleaf stamping, printed from new, clear. read- gers, each operated shattered the more level- headed and able type on good quality book paper. There is three -quarters of an inch space is not ad- slow -going intellects of the day, it really an illustration at every point where a picture visable. does not seem so rankly impractical to con- will help. Hundreds of thousands have been To avoid this difficulty the screen is first jecture on the possibilities of such a high sold on a money -back guarantee of satisfaction. divided into zones, and in each zone there speed railway somewhat of the type here described. A fortune awaits the man who The regular price is 51.25, but fora LIMITED are five wires; the zones were represented TIME you can buy the ones you want, post- by letters and the wires by numbers. Thus is big enough for the job. It wants an- paid, delivery guaranteed, for only 50 cents. would be other Tesla or Edison and he is bound to a bird in the center of the screen later. in front of the ball which connected wire arrive sooner or You Run No Risk! Money Bach if Desired! Dl with wire Hl. There are vertical zones International Correspondence Schools and horizontal zones. Therefore, to estab- Box 6338, Scranton. Pa. of any object in the pic- OXYBENZYLMETHYLENGLY - Teen OUT Nana lish the location COLANHYDRIDE. ture, nine fingers were required for the INTERNATIONAL CORRESPONDENCE SCHOOLS vertical and nine for the horizontal, and at (Continued from page 8or) Box 6338 , SCRANTON. PA. each operation two fingers were necessary, percha, one of the best of the old insula- I enclose t - for which send me postpaid the one to establish the zone and one to estab- tors, a specific resistance but little higher. Handbooks marked X. at sic. each. I may return any or an film and get my money back within ten days from receipt: lish the wire dropt thru the perfora- BAKELITE -MICARTA is the name of Electrical Engineer's Advertiser's tions for the horizontal and one zone fin- Teiepb. sod Teter. Engineer's Business Man's a remarkable material developed a few Mechanic's Bookkeeper's ger and one individual finger to establish years ago by the Westinghouse research Steam Engineer a Steno. and Correspondent's Westinghouse Air Brake Salesman's the vertical wire so that each picture car- specialists. Primarily it is an insulating Civil Engineer's Window Trimmer's ried Coal Miner's Cotton Textile Worker's four perforations. material, but is also a superior product for Concrete Engineer's Farmers A special device has been built for perfo- various other purposes. Building Trades Poultryman's Plumbers and Fitter's Mariner's rating the film and which works automatic- Bakelite- Micarta is a hard, insulating IP Chemist's Automobile ally. This is the most amazing piece of material of high dielectric and mechani- work ever attempted by any human being cal strength, which will not warp, expand, Name Street and its inventor certainly deserves credit or shrink with age or with exposure to and No for his time spent in developing the elec- the weather. It is infusible and remains

tric moving picture target. unaffected by heat until a temperature is City . State You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com 852 "I HE ELECTRICAL EXPERIMENTER March, 1917

reached that is sufficiently high to carbon- of gas in a small volume exerting a force ize the material. Heat does not warp it, great enough to cause the cork stopper to and it will stand an electric arc better than be pushed out. In the second case a large hard fibre, hard rubber, built -up mica, or amount of gas was also formed but the any molded insulation of resinous or fibrous gas was not confined to a small volume but material. The coefficient of expansion is could occupy the necessary volume in the low -about .00002 per degree Centigrade. atmosphere and hence we had no explo- It is insoluble in practically all the ordinary sion. The gasoline engine is nothing but The Uni- Lectric Is a complete electric solvents such as alcohol, benzine, turpen- service station in home size. Generates a contrivance for making explosions in standard 110 -volt direct current. Big ca- tine, weak solutions of acids and alkalies, succession; these explosions being utilized pacity -operates one to 60 lights, electric hot water, and oils, and is not motors up tot h. p electric Irons, electric affected by to move a piston, which in turn causes a heaters, vacuum cleaners, force pumps, ozone, a feature that makes it superior to churns, separators, washing machines, etc.-- wheel to rotate. 24 hours a day. everyday in the year if you hard rubber, resin, etc., for electrical pur- Experiment ro. wish. Uses standard lamps and fixtures. Mix two parts (by poses. It is water -resisting and non -hy- weight) of Potassium Nitrat with one droscopic. Bakelite -Micarta can be sawed, part of sulfur and three milled, parts of char- No Belts -No Batteries turned, tapt, and threaded. It can coal. This gives the familiar mixture call- Our patented, high-speed, rotary Neese valve ngi¢ be punched only in thin sheets and can- operates the modern. high -speed generator ed gunpowder. If a match is applied with euch molded. a to that all necessity for storage batteries Is not be It takes good polish this mixture (it is not advisable esmoothnessliminated. Thus the renewal of batteries and battery and is accurate in thickness within close to use up -keep cost Is entirely done sway with. Outfit comes In more than about a teaspoonful) it will be one email compact unit, ready for quick Installation. limits. It is made in various grades in o found to burn quietly just Simple, dependable and e omled. The tire outfit plates, and rods, all same as the gasoline guaranteed for five yeses. Write today for free copy of tubes, having the did in the preceding experiment. If, how- our new catalog on farm lighting plants. general characteristics, but differing in ever, some of the mixture is placed in a ,Waterman Motor specific points to adapt them to different toyy cannon and set off Company kinds of service. by the aid of a 'ill Mt. Elliott Ave, Detroit, Mich. fuse, an explosion occurs The Bakelite -Micarta plate is made in analagous to the The first part of the preceding experiment. lighting plant that various grades, having different character- operates without The ordinary fire cracker storage hatter- lJèi=Lëtrie! istics. Each grade is designated by a num- or salute, is tou,is-guiíac ' i\t nothing but gunpowder packed tightly in a LIGHTING SYSTEM ber. small space and a fuse leading For instance No. 213 is to it. The the plate the fuse is nothing but some gunpowder standard one and is tan in color. It is use- wrapt loosely ful for all applications where high mechani- so that it burns quietly but steadily. A very good way of set- cal strength is required, or for general ap- ting off fireworks plication, on account of its electrical and for those who wish to mechanical qualities. it celebrate the Fourth of July safely and For short periods sanely but noisily, is will stand 140 seen in figure 10. temperatures as high as de- The figure is self -explanatory. grees Centigrade and has a breakdown The ter- minals of the secondary of the spark coil voltage of approximately 400 volts per mil. (hairpins heavy It will stand continuous service at 25 to 50 or wire) are placed so that the protruding ends are close together PUT UP A WIRELESS! volts per mil. Its specific gravity is 1.25, enough so its tensile strength approximately 19,000 that the spark will jump across The first thing to do is to but far enough apart at all buy a copy of Expert. lb., per square inch with the grain, and its other points mental Wireless Stations" strength under compression approximately so that the spark will not jump elsewhere. New 1916 edition, by Philip The switch E. Edelman. It shows you 40,000 lb., per square inch across the grain. is placed at a safe distance. just what to do, stop by This experiment was tried very success- step, exactly what you It can be sawed to size and drilled and tapt need, what Sire to make fully by a young experimenter, Mr. Arthur against the grain ; it can be punched with the aerial and where to put Pickett, using a "Bull -dog" spark it. how to connect up and simple dies in thicknesses up to '% inch. coil. adjust the apparatus, how If we strike a sharp blow on some of to cuver any desired dis- It is furnished in sizes from 1/64 to 2 the tance, bow to make your inches thick, up to 36 inches square. No gunpowder, we notice no effect. If; own instruments, etc. 272 however, we mix equal parts of Potassium pages. fully illustrated, cloth doubt about it- Bakelite fills a distinct want t The one book o w ant, chlorat and Sulfur, we find that the force Only [1.69; postage 11c. in the commercial electrical field. Insist on gelling the new 272 - of the blow is sufficient to set it off. Page edition te `r aitlmodmme,doee- Efficient miniature torpedoes are made by ry rasä ; ái° dmáá áßi Russia Wants More Electric Stations wrapping a small amount of this mixture bieatg ÌLóf át o morertca th `láláo together with a small marble in tin -foil. U. S. radio patents is included A committee on Russian industrial af- fairs reports that there is need for a rapid If thrown up and permitted to land on something hard, such as pavement, TCOMBINATIONis ook illlhesentttogethei increase in the means for generating elec- the the with 'EXPERIMENTS. force the marble is of cieics"woo tric power in Russia. At present there are of striking sufficient I.6U, to detonate it. On mixing four parts toor`only{-RS5 guarannteed 93 generating stations with a capacity of of 79,533 kilowatts in European Russia. this mixture with one of powdered Mag- PHILIP E D E L M A N, ßd0 tHagueAve. nesium, a good flash powder is made, which can be used for photographic pur- EXPERIMENTAL PHYSICS. poses. Finally the ordinary bullet is an FREE (Continued from page 804) application of the principles underlying sufficiently large cork stopper is available these two or similar mixtures. Here (d) a milk bottle will be just the thing. Punc- is a brass shell, (a) is steel or lead, (b) is Fine ttes ture two holes in the cork as far apart gunpowder, which on being sufficiently MANDOLIN, VIOLIN as practicable. Bend two hairpins as in heated, explodes and propels (a) for- $20 UKULELE GUITAR OR CORNET ward; (c) is the fulminate, ie., the mix- We have a wonderful new system of teething noto music by figure 9, and stick them thru the two holes mail. To amt pupila In each locality, we'll give a $20superbVlo- in so are about % an ture which is set off by the blow of the lis, Mandolin, Ukulele, Guitar or Cornet absolutely free. Verysmall the cork that they charge for lessons only expense. Wegu&ratites to make you player inch apart at the lower extremity. Soak trigger, the heat given off by which, sets or o charge. Complete outfitfree. Write atones -no obligation. a small off the powder. (See figure 11.) III: a wad of cotton about the size of SLINGERLAND SCHOOL OF MUSIC, Dept 165, Chicago, marble in gasoline, benzine or ether. Place Nitrocellulose is a substance far more the wet wad in the bottle and cork the powerfully explosive than either of these THE GILSON POCKET SLIDE RULE two mixtures and since on explosion it- Patented October 19, 1916 bottle rather tightly. Insulate the leads I This new elide rule nuisance any other pocket slide rule fm accuracy coming from a small spark coil (a % -inch gives off all colorless gases, it is used in In solving mathematical problems. Thin Instrument will solve any prob- lem involving multiplication, division. proportion, even and uneven wireless spark coil works admirably) so the manufacture of smokeless powder. Logarithms of number* and the Sines and Tangent. na powers. that they can be held in the hands. After Nitroglycerin resembles nitrocellulose in IM operation ie ve Mink and anyone can learn to use this s fide rule In a few minutes, and` can quickly obtain the result of any calculation, having moved away to a safe distance (in the violence of its explosive effects. One for example: Find the cube root of 817.49; answer 9.351; time required, using a Gilson Pocket Slide Rule. 16 seconds. It is de of heavy an extreme case the bottle might burst), volume of nitroglycerin yields about 1300 waterproof bristol and just fits the pocket e 4 in. by 7 in. Price with complete inafructione. hoc- Imitation leather carrying case 2k touch the ends of the hairpins (a) with volumes of gas, which by the heat of re- extra. Send for free descriptive circulars. the action expands to 10,000 volumes so that GILSON SLIDE RULE CO. Niles. Mich. the leads. An explosion occurs and cork stopper is projected upward. Wet the force exerted is indeed enormous. A "'Reliable Supplies for another wad of cotton with the same liquid mixture of Sodium Nitrat, wood pulp and place it on a piece of asbestos, marble, and nitroglycerin is called Dynamite, WORKING MODELS or slate and light it. It is found to burn which can be handled with less danger. fully described in our interesting, new illus- Recently the Germans have developed a trated s0 -PAGE CATALOG. 5c. postpaid. quietly without explosion. In the first case Write today for a copy. SPECIAL ORDERS the vapor of the gasoline mixed with the powerful explosive called Trinitrotoluene, are promptly and carefully executed by our air in the bottle and the mixture on being which is prepared by the action of nitric mechanical department. Submit us your draw- is a can ings and specifications for quotations. heated by the spark, formed a gas which acid on toluene. It solid and a much larger vol- be transported with safety. IDEAL AEROPLANE & SUPPLY CO 70-82 W. 8'dway, N.Y. would normally occupy ume. This was the case of a large amount (To be continued.) You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com Mar cIt, I917 THE ELECTRICAL EXPERIMENTER

/ I A T V e v 111' Illli, Edited by H. GERNSBACK In this Department we publish such matter as is of interest to inventors and particularly to those who are in doubt as to certain Patent Phases. Regular in- i"FREE-lhfl.'I quiries addrest to "Patent Advice" cannot be answered by mail free of charge. BOOK-BULLETINS &ADVI,PE Such inquiries are publisht here for the benefit of all readers. If the idea is thought to be of importance, we make it a rule not to divulge details, In order to protect the inventor as far as it is possible to do so. Should advice be desired by mail a nominal charge of $1.00 is made for each question. Sketches and descriptions must be clear and explicit. Only one side of sheet should be written on. 255 OURAY BLD'C, WASHINGTON, D.C. SAFETY SWITCH GUARD. by a motor and perforated tape. Our ad- Don't Lose Your Rights (128.) John T. Dwyer, W. Philadelphia, vice is asked whether this can be patented. We publish form, called "Evidence of Con- Pa., has submitted to us a Safety Guard Answer. There is nothing new contained ception" by which you can establish your rights before sending the invention to anyone. It is your for preventing electrocution or shocks in this idea, which is practically the identi- best protection. We issue up-to -date bulletins of from touching the metal on knife switches, cal thing being manufactured at the present improvements wanted; aid inventors to promote the safety guard being arranged in such time by the Dodge School of Telegraphy their rights; render reliable opinions free of charge and secure valuable patents and trade-marks on a manner that it will enclose the blade Co., Valparaiso, Ind., to whom you might reasonable terms. Personal service assured by our and at the same time help prevent the write for their catalog. Service Guarantee Contract. References: from opened or closed. Our 2nd National Bank, Washington, The John P. switch being Roth Packing Co., Cincinnati. opinion is asked as to the patentability of COHERER. (132) Harold Stanford, Lawton, Okla., SIMPLY MAIL COUPON the same. LANCASTER h ALLwiNE, 55S Dewey Dtds.,trashinttee, D.C. Another device is also submitted, being a has sent us in a description and illustra- Send me free book "Inventions-Patenting and spirit level to determine whether a board's tion of a special coherer which is excited Promoting, Bulletins of Improvements Wanted and form "Evidence of Conception." surface is horizontally true. by electro- magnetic means in a certain blank Answer. Concerning the knife switch manner. Our advice is asked if the device Name is patentable and it has any guard, this is a very good idea, but unhap- whether mar- Address pily, we believe the high cost of making ket value. such an article of hard rdbber or other Answer. Your device in itself is not insulation, on account of the amount of new. Similar devices have been patented material needed would make the device pro- before. What seems to us as being new, hibitive, as far as its commercial phase is however, is the manner of connecting the A0) a. OUR IDEAS t S a Constant coherer to the aerial and ground, which There concerned. The idea, nevertheless, is an r Demand for Good Inventions seems novel and possesses several meritor- excellent one. a As to the spirit level, we think this a ious features. However, without having "WHAT TO INVENT" good idea and a patent might be obtained tested the device we could not offhand tell 14 upon it, but would suggest that you have whether it would be practical for long dis- and " How to Obtain a Patent" tance Thew Books sent FREE a patent attorney make a search as to the receiving or even for short distance If you have an Invention send patentability, first. work. We would advise you to have care- sketch for tree report regarding patenta- bl lty: It not send for free book. "What ful tests made before patenting the article. to Invent." TRAIN STOPPING DEVICE. From our advertisements In newspapers SWITCH. manufacturers are constantly writing to (129.) P. Traniello, Natick, Mass., sends us regarding the purchase of patents. us a sketch and writes as follows: (133) Albert H. Beiler, New York City, Their names and addresses are furnished our clients free of charge. We advertise "I am sending you herewith illustration asks: your patent for sale at our expense. of a train stopping device, which I think "Will you please inform me of the prac- DON'T WAITI Your Invention will never do you any good if some one else patents will stop a train in case an engineer should ticability of a device by means of which a it ahead of you. Write to us NOW. try to pass a danger signal set against him. single -pole, single throw knife switch may CHANDLER u CHANDLEE \Vould like to have your advice as to be made to operate any number of lamps Est. 20 years. 950 F St., Washington. D.C. whether such a system is practical and with successive intervals, lighting only one whether a patent can be obtained on it." lamp at a time. Thus, by closing the Answer. We have carefully looked over switch, Light No. 1 will light and remain the idea, but it seems to us that the idea so until the circuit opens again. With the is not practical enough to warrant rail- circuit now closed a second time, Light No. roads using it. Besides, there is a very 2 will light and remain so until the cir- similar device used at the present time in cuit is again opened, and similarly with any the New York Subway, and the usual au- number of lamps. tomatic block systems which are now in Answer. The idea is a good one, but vogue all over the country are a great without more information about the con- deal simpler, involving less expense, and struction it is impossible to fully advise -the ONLY kind Wanted and seem to us to be capable of working with one. There is unquestionably a demand BOUGHT by Manufacturers. more certainty than the device submitted. for devices of this sort, but you should Send tic. postage for new book of not forget that they must comply with the Extraordinary Interest to Inventors. PORTABLE ELECTRIC BRUSH. regulations of the Fire Underwriters, which R. S. & A. B. LACEY (130.) G. Ladermann, New York City, are very strict, and not all the devices lend 63 Barrister Building, Washington, D. C encloses sketch and description of a port- able revolving brush which he thinks would come in handy for porters, who have a Write for List of Patent Buyers who good deal of brass to polish, also for jew- PATENTS WANTED desire to purchase patents and What elers and the like. Is the idea new and To Invent with valuable list of Inventions Wanted. $1,000,000 in prises offered for in- is it patentable? ventions. Send model or sketch for Free Opinion as to patentability. We have a Answer. Nothing new is contained in Special Department devoted to Electrical Inventions and are in a position to assist the suggestion. Merely by putting a re- and advise inventors in this field in the development of their inventions. volving brush on a portable motor does FEES --WE ASSIST INVENTORS TO SELL THEIR PATENTS not make the article patentable, as no new MODERATE features are contained in the device. By Write To -Day for our Five Books sent free to any address. (See attached coupon:) just taking a motor and mounting some wFREE :we - -_ sort of revolving article on it does not en- title you to a patent. I VICTOR J. EVANS & CO., Patent Attorneys NEW YORK OFFICES: 189 -t9t Broadway PHILADELPHIA OFFICES:. i429 Chestnut St. SELF -SENDING KEY. Main Offices: 779 9th Street, N. W., WASHINGTON, D. C. (131.) Robert L. Hazeltin, Jamestown, GENTLEMEN: Please send me FREE OF CHARGE your FIVE Books as per offer. N.Y., has submitted a scheme for a self - ! NAME ADDRESS teacher to learn the code which is operated You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com 854 THE ELECTRICAL EXPERIMENTER March, 1917

themselves to commercial exploitation for that reason. We would advise you to get in touch with a patent attorney. THE CALCULATION AND MEAS- UREMENT OF INDUCTANCE. WANTED -Railway Mail Clerks 11111110 111 (Continued from page 850) 1 COMMENCE $75 MONTH INCREASE TO 5150 MONTH a greater or less self -inductance than that Common education by formula. This sufficient. BBB Y. 11' given the current sheet 1 6 depends upon the ratio of the diameter of Sure pay. Franklin Institute the wire to the pitch of the winding. Tak- Life job. Dept. W104 Rochester, N. Y. Pull unites- Sirs; Send me without charge, ing L for the actual self -inductance of a essary. o+ sample Railway Mail Clerk Es- coil and Ls for the current -sheet value as JQ aminatioa questions; list of other o government yobs w easily obtainable found by any of the formula herein cited, 0 and free book describing them. we obtain the expression: A Ratchet Hand Drill L=Ls -DL; Nome is a necessity because you are The quantity DL is found by solving the Address most apt to get into crooked following equation: corners in doing small work. DL- 47rXaXn(A+B) ; Send for large Wherein R E E a =mean radius of coil in cms. Catalogue of MILLERS FALLS n =whole number of turns in coil. Practical Mechanical Books 'e._3.1416. F HAND DRILL No.305 While A and B are constants to be 'taken FOR HOME STUDY has ratchet on crank handle which is from the accompanying tables I and II. operated by simply raising and turn. The correction term A is dependent upon Best Books for Electri- - cians, Telephone Men, i g a knob to right or left. Detach- the size of the bare wire, having diameter re will hold all drills Motion Picture Opera - ;na,t able hollow handle the pitch "P" of the AUTOMOBILE up to % capacity of chuck. "d," as compared with tors, Engineers, Railroad `yt "n d Slotormen, Drafts- STARTING Here's a hand drill made up to the Men, "h LIGHTING quality standards that such a tool winding, or' on the value of the ratio - men, Automobile MANLY deserves. P Mechanicians, Plumbers, Carpenters, Builders, Mechan- The two values must be in units of like Ask your dealer to show you Sign and Card Writers, ic's Handbook. containing much val- denomination, i.e., either in cms. or in in- uable mechanical information never also Bookkeepers a n d before printed, and pocket catalog Civil Service Applicants. free on request. ches. When the value - becomes less P F. J. DRAKE & CO. MILLERS FALLS CO. than 0.58, A is negative and in such cases Ave. Dept.6. 1006 Michigan \ "Toolmaker to the Mailer Mechanic" when the numerical values of A are great- CHICAGO MILLERS FALLS, MASS. er than those of B, which is always posi- Sent Postpaid for $1.00 N. Y. Office 28 Warren Street tive, the correction DL becomes negative, and hence L will be greater than Ls. 04+OcG

JANUARY MEETING OF THE A.I.E.E. The American Institute of Electrical En- gineers held their 328th meeting on Janu- ary twelfth under the auspices of the Pitts- burgh Section of the Traction and Trans- portation Committee at the Fort Pitt Hotel, Pittsburgh, Pa. An interesting paper entitled "Regenera- tive Braking of Electric Vehicles" was pre- sented by R. E. Hellmund of the Westing- house Electric and Manufacturing Compa- ny. This paper presented an exhaustive study of regenerative control as applica- ble to the various systems of electrical rail- ways ; and in view of the wide possibili- ties which exist for successful regeneration, the subject of regenerative braking is now rapidly assuming considerable commercial importance. It possesses many practical advantages in electric railway work and for heavy railroads, as well as in various oth- er fields, such as steel mills, etc., which cause this subject to be of particular inter- est to electrical engineers engaged in rail- way work and other industrial applica- tions of electric power.

THE QUENCHED SPARK GAP. (Continued from page 8r5) the same amount inserted in the secondary, circuit, multiplied by the square of the ra- tio of transformation. The opposite holds true in the case of capacity, which is trans- ferred from one circuit to the other by dividing by the ratio squared. Reactance, as stated before, behaves like resistance. Our reactance adjustments can be most yES, for this insignificant sum you can get the great 1916 edition of the Cyclopedia made in the primary side of of Applied Electricity. See it before you decide to buy. No matter what you conveniently want to know about electricity -here it is at your fingers tips. The great author- the transformer. ities have written it in plain English-so that you can grasp it instantl These books The condenser C is connected across the mean secondary terminals of the transformer more money for you -promotion -the position you have been dreaming about, apparatus. Its capacity and all you need to do to get the entire seven volumes is to send us your name and without any other address. Use them seven days at our expense before you decide if you want buy. may be roughly determined by the usual to power relations, assuming the voltage is known, and should be made adjustable. When the apparatus has been arranged All About Electricity! as shown, the primary mains are connected indica- The 1916 edition of Cyclopedia of Applied Electricity contains 3,500 pages, 7x10 to the transformer and the current in.; 3,000 illustrations, full -page lates, diagrams, etc.; hundreds ted on the ammeter noted when Rp has of valuable tables and The formulas; carefully cross-indexed for quick easy reference. Printed on special quality been adjusted to maximum indication. paper and bound in half red morocco, gold stamped. Seven volumes. The standard is increased until the capacity at C then of America -the information that is vital to you and to every man who is interested maximum is again obtained and its value in electricity. And it is yours -on a startling offer. noted. This procedure is gone thru for the different capacities and the corresponding r Read These Subjects ammeter readings entered in a table. Care Elements of Electricity- taken that the condenser ca- ia f7ndZ Electrical Measurements should be Shipped FREE! w send the -Underwriters' uire- pacity does not exceed the limiting value ments- Theory. Calcula- entire seven volumes prepaid right to your home, so that you tion. Design and Con- set by the equation:- can see and examine them for yourself. Keep them seven struction of Generators and Motors Dynamo- full days. Then decide if you can get along without them. Electric Machinery-- you you ean, send them back. Lighting Machinery C 3552L' If think If you keep them, Power Transmission - pay $2.00 after the seven days' trial -and then $2.00 a Eieetric Railways -Power- L represents the primary radio in- Stations -Switchboards where month (50e a week) until $19.80 has been paid. You are the and Switching-Storage ductance for the wave length to be used., sole judge -you do not risk a penny. This offer is open to Batteries Applied Eleo- trochemistry- Electric Any excess of this value would not permit everyone in the U. S. and Canada. Elevators- Electric- Weld- of sufficient inductance in the primary of ing and Heating -Wire the oscillation transformer to permit of and Wireless Telegraphy. efficient energy transfer to the antenna. Consulting Service FREE ! which gives the The condenser capacity A year's Consulting Membership (regular price $12.00) will t largest ammeter reading at resonance be given free if you send your order at once. The advice of a Ameri can Technical Society be one used. If the primary Chicago, U.S.A. should the an entire corps of electrieal experts is yoursto help you E 7443 of the transformer is provided with taps your progress-for a whole year FREE! ase send me Cyclopedia should be of Applied Electricity for seven for power variation, each tap days' free examination. If I measured in terms of resonant condenser keep the books will send $2.00 capacity and tabulated for reference. It seven$ d80s and $2.00 a is possible the reactance in the pri- month until $19.80 has been paid, that Send the Coupon when books and Consulting Member - mary of the transformer of the closed core See these books for yourself before you decide to buy. will type will not be needed for some adjust- , r iitty wyon and hód b oks a bject ments, but the condensance of the total cir- Remember-don't send us a penny. Just fill out your order. cuit should be increased so that the adjust- the coupon and mail it. Will send you the entire ments may be made by this means, as great- seven volumes prepaid. Use them seven days- then if you want to buy pay the special reduced price at Name - er flexibility is then obtained. the rate of $2.00 a month. Send the coupon now. Your It will be noted that the writer has re- ambition says -act -see for yourself. ferred to the closed core transformer as ' being the best for quenched gap work. This AMERICAN TECHNICAL SOCIETYOCIETY hse had nn prenons dealin¢e with you. l referto, to question of difference between the two Dept. E. 7443 CHICAGO, U.S.A. 1 types of transformer has been disputed for several years and various opinions have You benefit by mentioning "The Electrical Experirnenter" when writing to advertisers.

www.americanradiohistory.com 856 THE ELECTRICAL EXPERIMENTER March, 1917

been exprest. The reasons why the author has suggested the use of the closed core type are as follows: In favor of the open ` core type, it might be said that it possesses r` the desirable high leakage characteristic a and is simple, both in design and construc- tion. The closed core type requires less -- copper and iron for a given output, and consequently the losses are smaller and it is more efficient. The relative space taken up by the two forms favors the closed core type also. It will be seen that the closed core instrument is to be preferred. How- ever, the open core type can be used, pro- vided a suitable reactance is inserted in the primary to compensate for the leakage re- actance of the other type. This is in addi- tion to the adjusting reactance used in the preceding experiment, and can be incor- porated in the adjusting reactance itself. It has been the experience of various en- gineers working with the quenched gap that a destining of the transformer circuit about 15 per cent off the resonant fre- quency just determined was desirable in Don't Monkey order to obtain a clear note. This may Strong of Limb be done later when the gap is put in op- Keen With the Buzz -Saw eration by readjusting the reactance in the and of Eye primary. An explanation of this detuning -growing more husky, hale, hearty, ro- and don't experiment with an unreli- process as given by a well -known engineer bust, deepchested, pink -cheeked, red. able brake. It is dangerous business. is somewhat as follows: blooded every day-that's your boy when Experienced cyclists for the past six- Referring to Fig. 2, which represents the he rides a 1917 Electrically Equipped teen years have given consideration to variation and phase relations of the cur- only one brake -the rent with the various reactance adjust- ments as abscissae, the heavy dotted line drawn parallel to the Rp axis indicates the zero phase axis. Above this line capacity predominates and the primary current leads, while below it the current lags. It &dim DUPLEX COASTER BRAKE will be observed that the current curve has an asymptote on an axis at right angles Its reliability is known. It has proved itself Rp the point. In and thousands of times to at resonance other d- pendable thousands at this a Bicycle under all riding conditions. Cyclists know words the current point reaches they can trust it. because it has never failed. high value, and is limited only by the re- Through actual service it has earned its repu- sistance of the circuit. This would indi- Nothing like an Indian to keep him out- tation as the standard brake equipment - doors where he can broaden mentally 100 %q efficient. cate that the point of exact resonance does not represent a and physically, where he will be in daily A d" safe working condition "Corbin Control Means Safety owing to the excessive current obtained. contact with the type of boys you want Powerful, durable and sure; smooth in action. Of course this could be controlled by means him to cultivate. easy of operation. gradual or instant of grip. There is no doubt about it. the Corbin Duplex of resistance, but this would reduce the And in the Electrically Equipped Indian is the only brake you can afford to equip to efficiency of the apparatus and it will be he has the strongest, most highly per- your bicycle -old or new. It doubles the fun found better to detune from the resonant and safety of riding. Insist on the Corbin fected bicycle money can buy. Snappy Duplex. It is the only brake for you to use. frequency. The shaded portions of Fig. streamline Indian Motocycle effect, at- At all bicycle dealers'. Ask for it. 2 show the operating regions after this is tractive red finish, Indian tank battery The Corbin Screw Corporation done. holder, Indian crank hanger, Indian front T heAmerkan Hardware Corp.,Suceessor The question now arises as to the differ- fork with quadruple crown and braced 216 High Street, New Britain, Conn. ence between these regions. It will gen- members, Indian rear wheel stand, Indian Branches: New York, Chicago, Philadelphia erally be found that operation in the re- cross -bar motorcycle type handlebars, Makers of Corbin -Brown Speedometers gion marked II will give the best results, brake. front and rear mud guards, Troxel from the standpoint of spark clarity. From saddle, large electric light, powerful re. A to B the current will lead, causing a rise Hector. All Indian built and backed. of generator voltage because of the rapid re- Indian Electrically Equipped Bicycle, $45 ; ten other duction of initial gap resistance, due to the models, $26 to $45. Write for /9 /7BicycleCatalog. fact that currents in this phase relationship Makers of the famous Indian Big Twin with cause the armature reaction to aid with Powerplus Motor, Side Car, and Light greater extent the generated E.M.F. In the Twin with Four Cycle Opposed Motor. region C to D the opposite holds true, i.e., HENDEE MANUFACTURING CO. that the voltage will fall as the resistance Mass. of the gap drops, resulting in practically 826 State St. Springfield, a uniform current thru the gap, and a pure Largest Motorcycle Manufacturers in the World note. This is probably the reason why it is better to work above the resonant point rather than on or below it. Experiment under the actual conditions is the only Convert Your Bicycle Into means by which the exact operating point a Motorcycle may be determined. PORCELAIN "THAT'S OUR BUSINESS" Motor flts any wheel. Best. Referring to Fig. 3, it will be seen that r-s` most reliable. Best hill climber. More the quenched gap G and inductances Lt STEFFEYS in use than all others. A floe Standard and Special Shapes, Regardless motor for running small Dynamos. Lathes and and L, of the radio circuit have been con- of How Difficult small shops. Motors only as low as $16.95. nected in, and coupled to the antenna cir- SteSer Mfg. Co., 5025 W. Brown St., Phila, Pa. cuit. Previously, however, the two radio We illustrate one hard shape we make. A pair of rolls 7y" long and 1I" in frequency circuits are tuned to resonance diameter with 8 hoes on ends and middle. and the coupling adjusted until the two They must be perfectly straight and we emitted waves lie close together. Call this make them so. It's hard but not for us. $40 We can make your difficulty designs also. MOTORCYCLES the critical coupling. Now, using all the Send us blue print for quotations. and BICYCLES at rut prices. Singles and twins $25 to $100. gaps at hand, the mains are connected to New Motorcycle Tires33. the primary and the set operated. Allow Automobile Tires $3. Best Uniot Electrical Porcelain Works Motorcycle Belts $5. Carbur- the gap to operate for about five to ten lors $6. Sra coils $6._ Second - N. handB.cyciee $5. Tandem, $IS. tien Bicycles at Factor, Prices. minutes, in order to complete the chemi- TRENTON, J. Deninger, The Price Cotter, Rochester, New York cal reduction in the sparking chamber. You benefit by tnentioning "The Electrical Experimenter" when writing to advertiser:. www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 857

If the gap has not been previously sea- soned, it will take a longer time for this action to ensue, for the reasons previously pointed out. By listening in on a wave meter, the pitch and clarity of the note may be determined, and when this has been par- tially cleared the current may be shut off. Now from the table obtained during the resonance adjustment just made on the transformer circuits, find the amount of reactance to be used in series with the pri- mary. Set Rp to this amount and place the set in operation again, listening in on the wave meter (or receiving set). Vary the amount of reactance in series, keeping above the resonance point, until the note is clear and the current in the primary is at a maximum. The coupling may be adjust- ed at the same time as the reactance exer- cising care not to deviate from the criti- cal coupling by a large amount. If an We Pay the Freight integrating wattmeter of the indicating type is at hand, it should be placed in the Your Choice of 44 Styles primary circuit of the transformer and Colors and Sizes in the famous Ranger Line of used to determine the point of maximum Bicycles for Men, Women, Boys and Girls. Also power. Finally the antenna current is no- Other Styles $1 A ,75 ted and the point at which the primary 83 and Sizes 1 `t and U p power or current is maximum, and when Electric Light the ratio of this power to the radiation Five Year Guarantee current is maximum, the note of the spark and Auto Horn and Accident Insurance FREE clear and the wave lengths not too far apart, the transmitter may be said to be Send Coupon Now for Wonderful Offer operating at its highest efficiency at the FREE wave length used. This adjustment should be made for all taps on the power varia- tion switch on the primary of the trans- No Morley In Advance former, and the values of the various units tabulated for future reference when it is Don't hesitate. You can get this famous Ranger Motorbike or any other bicycle you want without one t in advanee -no red tape or delay of any kind. Just your mere request brings the bicycle of desired to use less power. your choice -the size and color you want. equipped in every particular to suit you. When the bicycle comes, you can decide to keep it on our 30 -Day Free Trial Plan or send it back at our It may be found in reference to the an- expense. We won't persuade you to keep the bicycle. The bicycle in your own hands, under every day use. tenna current that the hot -wire type of sell itselftself to you, or we'll take it back, and not ebarge you one cent for the use of it. ammeter is not sufficiently sensitive to follow the changes of current when the The Greatest Bicycle Ever Built quenched gap is used, and the adjust- We have spared no expense to make the Ranger Motorbike the best and most completely equipped bicycle in the world. It not only excels in construction, but it also answers the cry for SPEED. furnishes extra ments of coupling, etc., may have to be riding COMFORT. Its ENDURANCE is remarkable. It is a BEAUTY in appearance. Atogether it stands made slowly in order not to miss the max- without a rival -on country road, on steepest hills, on city boulevards. on forest trail. imum. It is suggested that this form of Note This Wonderful Equipment Free FREE # 5. Premium Outfit! current measurement be replaced with the You'll simply fall in love with every detail the cali- Special Make up your mind NOW to get a Ranger Motorbike thermo -junction and milli- voltmeter, T rt e Front nt reinforced withersr, Tust he or other Ranger model and we'll send you FREE of R.M.S. amperes. The Steel Tool Box between Top Bars, which looks ex- cost this $5 Outfit. $2 Bicycle Pump and Pump Clips, brated in terms of actly like gasoline tankrr on motorcycle. Special Sterling Wrench. Hub Shiners, Silver Queen Bell, Cor- author hopes at some future date to give are:-Motorbike Bars, bin Stand Lock, Steel Screw Driver Trouser Guards, dal CterBrske Pantdt Motorbike Saddle, Large Can of Oil Quick Action Motorcycle Stand, a more detailed description of this appa- Quick Detachable Mud Guards, Imported Bramp- Roll of Tire Tape, Spoke Tightening Nipple Grip. ratus and some of the results obtained by ton Roller Chain, Electric Light, Auto HandHorn, All this in addition to the reguar tool outfit of Sampson Tires. In addition, we give you FREE, a wrenches, repair kits, etc. its use. $5 Tool Accessory Outfit described on this page. By reading carefully the foregoing para- this Motorbike or any MAIL THIS COUR 01.1 anger me or ]n- graphs, and also by extending the study of Special -Now Getoth er R 5- Year Guarantee, Accident Insurance. Send coupon MEAD CYCLE CO., 19 N. Canal St., Chicago this gap to other available publications for Big Book showing all styles, sizes, colors from Without obligating me in any way. please send me your there is no doubt that some of the mis- which to choose. We 11 ship bicycle freight charges Big Bicycle Book and _particulars of your No- Money -In- fully prepaid. If you believe it the grandest bar- Advance,30 -Day Free Trial Plan. Also send me informa- conceptions concerning the quenched gap gain and greatest bicycle ever offered, keep it on our tion regarding Special Liberal Terms am] Particulars of may be it may then enjoy a 30-Day Free Trial Plan, or return it at our expense. Extra Inducements and Privileges. corrected and Send coupon for book -while our liberal Introduc- more extensive use. This gap will not tory Offer prevails -then send for bicycle you want. raise the frequency of the spark, nor will Name it do any other of the astounding and phe- CYCLEtCOMP nomenal things sometimes claimed for it, MEA 't9 N. Canal St. Address but it will allow a reduction of decrement of the radiation, at the same time increas- ARMY AUCTION BARGAINS YPEWRITERS efficiency the transmitter and Saddles, $3.00 up. New .:niforms, $1.50 up. T$10 and Up. All Makes ing the of Army 7 shot carbine $3.50; etges.11Se each Save $25 to $50 giving the spark a clearer tone. D. S. N.N'incbester blgb palter use 6m/ m, S9.13 Teambaruesa$21.55 up. G.w.ArmyEevolvers,$LCS in rebuilt at the factory by the well - In order to aid those who have as yet ar1ttt,4r Remington Army Revolver, $4.85; ogee, le each known "Young Process.' Sold for low ' maser nigh Power rifle with 200 elges. $10.85 or rented. Rental had no experience with quenched gap de- cash -installment 15 Acres Government Aoetion Goods Samaras applies on purchase price. Write for sign or who have met with failure in their illoatrated and described in 428 lame page wnote- aale and retail cyclopedia Catalogue, mailed 22e hull details and guarantee. Free trial previous attempts, the writer has included east and Sae west of Ml,olselppl Liver. the design of a small gap suitable for use FRANCIS BANNERMAN, 601 R »OADW eY. NEW TORT Young Typewriter Co., Dept. 174, Chicago on a 60 cycle, quarter K.W. closed core transformer having a secondary potential C4 THERE'S MONEY /NIT" of the order of 10,000 volts or under. In case it is desired to increase the spark fre- =HOME- quency and at the same time retain the de- Ñciffr= AR1 TELEGRAPHY sirable quenching qualities of the quenched - MORSE AND WIRELESS= - gap, it is recommended that a rotary gap - and the quenched gap be connected in series, as has already been suggested by TEACH YOURSELF Mr. Blatterman. - in half the usual time, at trifling cost, with the Referring to the Fig. 4, the various parts wonderful Automatic Transmitter. THE OMNIGRAPH. .of the gap may be seen. The plates are cut Sends unlimited Morse or Continental messages, at from sheet brass, or cast and trued on a any speed, just as an expert operator would. lathe. The general experience, however, Adopted by U.S. Gov't. 4 styles. Catalogue free. will be that it is better to cut them from 1% -inch bar stock, as the chucking is sim- OMNICRAPH MFC. CO. plified and the waste is not great. A word might be said in regard to the 39L Cortlandt St. New York :gaskets. This has been the cause of fail- You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com 858 THE ELECTRICAL EXPERIMENTER March, 1.917

ure in a great many quenched gaps on account of leakage. The writer has tried nearly everything in the line of insulating materials and has found that ordinary card- Marconi board, impregnated with an insulating var- nish containing rubber, gave the best re- School of Instruction sults and at the same time was much more economical than any of the others. The Announces the opening of an WIRELESS number to use in each gap of course de- EVENING CLASS operating spells OPPORTUNITY pends on the thickness of the material em- beginning February 1, 1917. today. ployed, and the total voltage to be used The great demand, rapid pro.. in the gap, and can be determined experi- TECHNICAL -TRAFFIC -CODE motion and increased salaries make mentally. In mounting the gap apply suffi- Instruction, this cient pressure but do not overtax the ma- Monday to Friday, work very attractive. We posi- beginning at 7:45 P. M. tively have good positions waiting for terials supporting it. The elastic limit of the materials shown in the drawing is great Students Trained Without Charge our graduates; operating in all parts enough, provided reasonable care is exer- of the world, coast -wise, transatlantic, cised in assembling the gap and clamping Day and evening classes con- transpacific, etc., etc. Our special the plates. vene throughout the year. If the note of the gap is not clear after Spring class for Day and Evening making the adjustments according to the Immediate positions assured to students starts April 2nd. Easy pay- preceding paragraphs, either the gap may graduates. Several hundred ments if desired. be leaking, is too short, or the condensers or the gap may be brushing. There should licensed wireless operators Send for special literature. be absolutely no brush discharge around required coming year - fifty apparatus using a quenched gap. When licensed telegraphers wanted this condition does exist, it will invariably EASTERN RADIO INSTITUTE be found impossible to thoroly clear the immediately. note. Call, Phone or Write 8998 Boylston St. BOSTON, MASS, The coupling adjustment with the quenched is INSTRUCTING ENGINEER gap a delicate one and should EDISON BUILDING be made carefully. In Fig. 5 is shown graphically the gen- 25 Elm Street New York City eral effect of the coupling adjustment on the radiated energy. These curves for the case of a quenched gap and synchronous rotary gap were obtained with the appa- SeeTheWorid,.. ratus shown in Fig. '3. The sharp rise to And THE the maximum in the case of the quenched r '' Y. M. C. A. RADIO SCHOOL gap is clearly shown. Another point of in- terest, is the increased radiation over -that desires to open communication with obtained with the rotary. The maximum young men wishing to qualify as radiation obtained with the synchronous rotary gap was nearly 4.4 amperes, while Wireless Operators that of the quenched transmitter was 50 per cent higher. 6.7 amperes. Decrement EXCEPTIONAL OPPORTUNITIES readings were made for each coupling ad- Commercial and Marine justment con- Write for Booklet to determine the boundary operators in great demand. Good op- ditions of operation in order to keep the portunity fcr you in well paid pleasant radiation within the limits defined in the profession. Y. M. C. A. RADIO SCHOOL radio legislation. It was found that at 145 East 86th St. New York, N. Y. about two inches coupling, the quenched Highland Park Course gap radiated practically one wave. while Very Thoro for a condition even approaching this the We teach how to build, install and coupling with the rotary gap had to be maintain wireless stations. We also oe- in. in offer strong practical courses in Elec- "Never Mind loosened to 4.5 This resulted the trical Engineering. How Strong antenna current dropping to about 2 am- You Are- peres, which is very low compared with Write today .hulme "Çet There" bookld the 6.6 amperes obtained with the quenched HIGHLAND PARK COLLEGE gap. 291 H. P. Sta. Des Moines, Iowa It is at once apparent from a considera- tion of the above results that the quenched type of spark transmitter is appreciably more efficient in every respect Learn Wireless Under if TESTING HIGH VOLTAGES WITH , SPARK GAPS. Marconi's Chief Instructór What D'ye KÑÚ. (Continued from page 822) To-day it's a battle of wits -and brains win. tive air density should be taken from table SPECIAL, EVENING COURSE Muscle and brawn don't count so much as they below. for advanced amateurs begins In next 30 days. Out - used to. The great question now is "What do Values of relative air density and corre_ of -town men should write for Information about tem- you know ?" It draws the line between failure porary day employment and living conditions while and success, between a poor job and a good one. ponding values of the correction factor are etudying. Our students may enter the Marconi tabulated below. It will be seen that for service direct. What do you know? Have you special ability? Radio Operates are new in Great Demand you " values above .9, the correction factor does Could "make good in a big job right now? Great stress islald on laboratory experiments, with com- For 25 years the International Correspond- not differ greatly from the relative air den- plete commercial apparatus. Special training given on ence Schools have been training men for bet- sity. advanced types of Trans-Oceanic Equipment. Course ter work and bigger salaries. They can train under the personal supervision of the Instructing Engi- YOU, no matter where you live, what hours The Spark -Over Voltage, for a given gap, neer of the Marconi Co. Send today for our folder E. you work, or how little your education. Mark decreases with decreasing barometric pres- EASTERN DISTRICT Y. M. C. A. and mail the coupon and find out -it won't sure and increasing temperature. This cor- Marcy Ave., near Broadway Brooklyn, N. Y. obligate you in the least. rection may be considerable at high alti- 13 minutes from New York City Hell. 113 minutes from Hudson Terminals, OUT HERE tudes. INIIRNA;10NAt CORRESPONDENCE $0100LS, Bot 5339, Soantm, Pa. The spacing at which it is necessary to Explain fully about your X Course in the subject marked set a gap to spark over at some required Civil Engineering ADVERTISING ID CHEMISTRY WIRELESS Electrical Salesmanship Illustrating voltage, is found as follows: Divide the re- OPERATORS team " Commercial Law Farming Mining " Bookkeeping Poultry quired voltage by the correction factor giv- SEE THE WORLD Mechanical " Stenography French en in 4. Positions always open. Good Merbenirl Drafting Civil Service German Table A new voltage is thus ob- salaries. Day and evening sessions. Sreblteetoral Drafting Ry. Mail Service itdian tained. The spacing on the standard curves Correspondence courses. Wireless ARCHITECTURE AUTOMOBILES SPANISH obtained from Table 3, corresponding to apparatus for home use. Send this new voltage, is the required spacing. 2 cent stamp for catalog. Name Phila. School of Wireless Teleg. The voltage at which a given gap sparks 10 Parkway Bldg, Philadelphia, Pa. Address over is found by taking the voltage corres- You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com March, 1917 THE ELECTRICAL EXPERIMENTER 859 ponding to the spacing f rom the standard values of Table 3, and multiplying by the correction factor. Wireless Tau ht B Mail TABLE 4. Air- Density Correction Factors for Sphere You Alrty Learn Theory, Code and Laws of Radio Gaps. Comm unication in Our School or at Your Home Relative fitting you for positions pay;ng good salaries with wonderful air Diameter of standard spheres in mm. - chance to travel the world over. It's the most interesting pro- density fession known and the demand for skilled operatorsis increasing. 250 500 62.5 125 Send stamp for catalog giving facts. Resident classes 0.519 0.50 0.547 0.535 0.527 \f open Oc . 2nd. 0.594 0.583 0.575 0.567 / 0.55 RADIO SCHOOL, 141h& U Sis., N. W., Washington, D.C. 0.60 0.640 0.630 0.623 0.615 LIPNATI ONAL OfferscfalSpe Adsvantage 0.65 0.686 0.677 0.670 0.663 WASHINGTON for These Courses. 0.70 0.732 0.724 0.718 0.711 0.75 0.777 0.771 0.766 0.759 1,11 0.80 0.821 0.816 0.812 0.807 0.85 0.866 0.862 0.859 0.855 Space 0.904 Line 0.90 0.910 0.908 0.906 Adjustment I want, through thi..s advrrii, m..n i, to t' tahllsh as friend ly hu.inrr> via- 0.956 0.955 0.954 0.952 Lions with you as I pos.slbty can. I 0.95 Carriage Return also, that it Is my 0,95 0.956 0.955 0.954 0.952 want you to realize 1.000 end Automatic earnest effort and Intention give. 1.00 1.000 1.000 1.000 you full, value every dollar 1.05 1.044 1.045 1.046 1.048 Spacer hat ou spend with me. This is the only way I can -uceeed. MY 1.092 1.094 1.096 1.10 1.090 advertlsemmnzicnnfrusly o 'iimore than four years. //Two Color /R bbon Shift I am building up my bus- A "SECRET" RADIO SCHOOL. iness on the foundation Tabulator Key of good value and square \Vireless Tele- dealings. I am saving The "Transmississippi R.H.Margin thousands of satisfied cus- graph and \Vireless Telephone School" was Release Shift Lock tomers thousands of dol- $20,- lars by supplying perfect incorporated with a capital stock of Back spacer -late style -visible writing -type- 000 by Sanford Schonbrunn, Roy A. Les- writers, at remarkably low prices. lie and Henry A. Meyer to "teach wireless All my transactions are bandied telegraphy and telephony by a secret pro - throughout by personal correspond- ence. I assure you every courtesy cess." and consideration In your dealings with me. Your order will have my prompt. careful, personal attention. 1 will be glad to do business with You. EXPERIMENTAL CHEMISTRY. (Continued front page 826) a s7sifí7'ï'r It is used: ALL LATEST 111 As a basis of various inks, as India IMPROVEMENTS ink and printers' ink, as well as an ingre- dient of black paint, etc. 121 Also as an ingredient of stove -polish. EXPERIMENT NO. 37- TYPEWRITER SENSATION Have lighted a candle, the oil of a kero- sene lamp, and the gas of a fish -tail burner, Free TRIAL -Use as You Pay also of a Bunsen burner. Take a piece of price glass and hold it across the flame of the Send me only $3.00 a month until the low total candle and notice if any deposit is left on of $49.15 is paid, and the machine is yours the glass. In the same manner hold a This is absolutely the most generous typewriter offer ever made. Do not rent a machine when piece .of glass over the kerosene lamp, over you can pay $3.00 a month and own one. Think of it- Buying a $100.00 machine for $49.15. the fish -tail burner, and the Bunsen burner. Cash price $46.45. Never before has anything like this been attempted. Do these substances tested contain the same elements? This is ascertained by com- STANDARD paring the results of the products on the VISIBLE glasses. UNDERWOOD It will be noticed and remembered that Perfect machines, Standard Size, Keyboard of Standard Universal Ar- the same element is contained in three dif- rangement, writing the full 84 characters- universally used in teaching the touch system. ferent forms-namely, in the case of the The entire line of writing completely visible at all times, has the inbuilt tabulator, with billing candle as a solid; in the kerosene as a devices, the two -color ribbon -with automatic reverse and key controlled shift, automatic in emitted from the flexible paper feed -automatic paper fingers thebaek spacer- roller bearing carriage action liquid, and the gas -in fact every late style feature and modero operating convenience. Comes to you with i H. A. $M lTH fish -tail burner, as a gas. The reason no everything complete, tools, cover, operating book and instructions, ribbon, practice paper ` Room 738 deposit is left from the gas of the Bunsen -nothing extra to buy. You cannot imagine the perfection of this beautiful typewriter seen have sold several thousand 231 N. Fifth Ave. burner is because there is almost perfect reconstructed until you have it. I ! perfect latest style machines at my bargain price and everyone of these thousands of CHICAGO, ILL. combustion taking place in this case. satisfied customers had the beautiful, strictly up- to-date machine on 5 days' free trial before deciding to buy it. I will send it to you F.O. B. Chicago for five days' free ' S h i y me the The deposit left on all the glasses is called 1 Lampblack. trial. It will sell itself, but if you are not satisfied that this is the greatest type- U N D E R WOOD writer you ever saw, you can return it at my expense. You won't want to return / F.O.B. Chicago, as de- itafteryoutryit-you cannot equal this wonderful value anywhere. i scribed in this advertise- Coke: ment. I will pay you the Coke is a fuel obtained by heating coal You Take No Risk -Put in Your Order Now $42.00 balance of the in confined places. This is done sometimes When the typewriter arrives deposit with the express agent $7.13 and take the / SPECIAL 849.15 purchase in heaps, just as charcoal is made from machine for five days' trial. If you are convinced that it is the best type - i Price at the rate of $3.00 writer you ever saw, keep it and send me $3.00 a month until my bargain I per month. The title to re- wood, in ovens. is in. but more frequently It price of $49.15 is paid. If you don't want it, return it to the express agent. ¡ fully also a by- product in the manufacture of receive your $7.15 and return the machine to me. I will pay the return fmainIt tá understood paid illuminating gas, remaining in the retort af- express charges. This machine is guaranteed just as if you paid have five days in which to ex- $100.00 for it. It is standard. Over one hundred thousand people own ' amine and try the typear rifer. ter the volatile portions, which go to make and use these typewriters and think them the best ever manufactured. i If I choose not to keep it, I will gas, have been driven off by the destructive The supply at this price is very limited, the price will probably r, carefully repack and return it be raised when my next advertisement appears, so don't delay. to the agent is under- distillation. Coke is a hard, irregular, brit- i stood that you give the standard Fill in the coupon today -mail to me-the typewriter will be ! guarantee tle and porous solid, having a grayish and shipped promptly. There is no red tape. I employ no solicitors , for one yyear. sometimes metallic luster. It does not burn -no collectors -no chattel mortgage. It is simply understood i so easily as coal and in consequence requires that I retain title to the machine until the full $49.15 is paid. / You cannot lose. It is the greatest typewriter oppor- a constant draft of air. Its combustion is tunity you will ever have. Do not send me one cent. accompanied with great heat and but little Get the coupon in the mails today -sure. smoke, which is a highly desirable quality in separating metals from their ores. Also ,+. Address it does not become pasty in the fire and HARRY A. SMITH some of the sulfur of the coal is driven off. 738 -231 N. Fifth Avenue Chicago It is used in metallurgical operations as a You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.

www.americanradiohistory.com 86o THE ELECTRICAL EXPERIMENTER March, 1917

reducing agent. Also in smelting and re- a Month COME TO DETROIT, THE AUTOMOBIL fining metals from their ores. ANO 50 The master- CENTER piece of watch EXPERIMENT NO. 38- Detroit trained manufacture-adjust- With a new set of apparatus used in Ex- men e t preference and ed to the second, positions, tem- jobs quickly. Think hat perature d isochronism. En- periment 35, and in the place of wood, fill It means to learq in the Michigan 1, ased at factory into your choice State Auto School. Factories endorse of the eanuisite new watchcases. the test tube with finely crushed Soft Coal. our School. glad to employ our graduates Heat as before and record your results. r offer them territory. Men needed verywhere as testers, repair men, cheufears, Test the gas at the end of the stricture tube tmndrede of our graduates start by applying a flame to the end. What were in sebus for themselves. Earn in $75 to $300 a Month the results? After the heating is complete, any auto proposition. Students We teach you to handle train- men and wo.acn Burlington actually build cars from start to finish gettingfactory examine and see if you can identify the bling. block -testing. ad testing, ev rything. The great Burlington Watch sent on simple request. Special complete course in Oxy- Acetylene brazin¢¢ welding and Pay at rate of $2.50 a month. You get the watch at substance left in the test tube. Test the cutting, separate from regular ou . All leading types of the same price even the wholesale jeweler must pay. farting, lighting end t nition ey,teme in operation. contents of the bottle with both red and boxier, eight -cylinder Ring used for road instruction. We have Write Today for Free Watch Book Chalmers 6 -30" chassis with 3400 r. p. m. motor. 1917 De- blue litmus paper and record your results. trotter -6 and Overland Delco System, used In Buick, Hudson, See handsome color illustrations of all the newest Knight complete chassis. designs in watches that you have to choose from. The three products of the destructive dis- Packard Twin -6, 1917- Willys- Your name and address on a postcard is enough. of [2] a liquid, Any Time Get this otter while it lasts. Write today. tillation coal are [1]a gas; Detroit is Place to Learn= -Start 44 auto factories in Detroit and 140 parts factories. We oper- rn on Watch Co. Dept 7493 19th & Marshall Biel. and [3] coke, which is left in the test ate Westinghouse. Autofite Biiur Service Stations. Students get actual experience in handltn Il kinds of electrical auto equiy- tube in place of the original coal. Just installed Sprague Electric Dynamometer tor block- Mineral Coal: testing for o open all - Graduate in 10 to 12 weeks. Enter

www.americanradiohistory.com rch, 1917 THE ELECTRICAL EXPERIMENTER hLl

atlually moving the flame toward the ire 1 end of the tube. Observe and record ¡the change that takes place in the lime - HTLY wtdCr, Can you remember any other ex- FIRE SALE!! OD BOOKS erinient which you performed, that caused A fire in our stock rooms caused many books to similar change in limewater? By corn - be damaged by smoke and water. Every one is vnng such experiments could you identify good except for covers and contains just as much is gas as Carbon Dioxid [COr]? valuable information as when it was new. But tYPF.tI'4ENiAL we can't Jell them for new. Rather than tiJERIMENT NO. 40- dis- ELETRICITT pose of them to dealers, we prefer to t7RSF, Allow the tube heated in the foregoing give our readers the benefit. What we experiment to cool and when cold pour its offer you is a combination of c t s is into a 200 cc. beaker. Let a small ,tream of water flow into the beaker. What Our Celebrated Wireless Course substance is carried away by the water? (160 p. 400 illus. flexible cloth) 'list is left in the beaker? What element Reg. Price $1.00. is taken from the Copper Oxid? Assum- List of Radio Stations of the World ing that Carbon Monoxid has been libera- (Call letters and location of every ted, the following would be the equation if station in the world) stiff cloth, the experiment was performed under prop- Reg. Price $50. er conditions: The Experimental Electricity Course O Cu (160 p. 350 illus. stiff cloth) Reg. Copper Oxid +Charcoal Carbon +Cop r [Carbon] Monoxid Price $1.00. ALL How to Make Wireless Sending FOR $1.50 EXPERIMENT NO. 41- Instruments (100 p. paper) Reg. p R E P A I D Thoroly mix a little boneblack with some Price $.25. cider vinegar in a small beaker. Fold a Remember the books are damaged but in many cases only the bindings have a h ter taper and place it in a funnel. Pour few water spots. But every book is absolutely complete. some boneblack on the filter paper and This is the biggest bargain in books we have ever offered. You should take advantage scoop out a hollow in the center of the of it at once. Send to -day. Remit by cash, postal or express money order to b meblack.. Into this hollow pour the mix- THE EXPERIMENTER ture cf vinegar and boneblack. Collect the PUBLISHING CO., Inc., 2ÉWFULTONC, TY N. fItrat and note its color. Filter a solution c i Copper Sulfate thru boneblack. Can the color Fe removed from all liquids by filter - inq them thru boneblack? Try a solution LOOK HERE, EXPERIMENTERS of red ink and water. From these experi- A COMPLETE ments can you form CHEMCRAFT OUTFIT FOR ONLY $1.50 a conclusion why crude POSTAGE PAID ANYWHERE sugar is dissolved in water and filtered thru IN UNITED STATES OR CANADA boneblack? Chemcraft No. I contains fourteen chemicals. Test Tubes. Glass Tube, M , etc., and a valuable in- struction book telling how to work 36 wonderful experi- EXPERIMENT NO. 42- ments in Chemistry and Chemical Magic. Place a small piece of Ferrous Sulfid in You can make gunpowder. colored fire and fire ink. a test tube and add 10 cc. of water and 5 manufacture fuses. make black and colored writing inks, cc. of dilute Sulfuric Acid. Result. Note prepare chlorine and hydrogen sulphide. You can pre- pare magic inks and papers. change water to wine and the odor. When the action becomes vig- wine into water and do dozens of others. These experi- rous, half fill the tube with boneblack. ments can be repeated many times and the outfit con- shake and observe the odor. definite tains all the chemicals and apparatus you will need. If With Chemcraft No. I you can also devise many new results are not obtained cork the tube and experiments of your own. of tie tube leaks make the opening gas- Chemicals and Apparatus for the Experimenter 6 '11 'y rubbing vaseline around the open - This picture shows Chemcraft No. 2. which con- We have just completed a price of tains 32 chemicals with complete apparatus and list chemicals and it.o, and shake thoroly. [Hydrogen Sul - apparatus for experimenters. Send 10c in or '.elution instructions for working 85 experiments in Chem- coin stamps d may be used in place of the istry and Chemical Magic. Price, postage paid. for a copy of this list. It will be valuable to you. crrot:s Sulfid and Sulfuric Acid, as these $2.50. West of the Mississippi and to Canada, $3.00. two ' THE PORTER CHEMICAL COMPANY ompounds are used to produce Hydro - Department B, en Sulfid.] Dealers, Write for Discounts on the Chemcraft Line Hagerstown, Md.

Super- Sensitive Microphone Only $6 Detectagraph $12 This instrument is offered atan extremely low price. It is This detecting instrument of marvelous aensitivitycan be excellent for building your own radio amplifier. Can also used for detecting secret conservations. Outfit consists of be used in many experiments where a sensitive microphone Sensitive Transmitter. 25 -ft. Black Cord. Receiver, Head- is required. band. Case and Battery. Send for One Today and Convince Yourself MICROPHO- DETECTOR COMPANY, Gaston Boissonnault, President, 119 Nassau St., New York Makers of Super -Sensitive Microphone Apparatus

a

Factory Rebuilt, Like New, at $52.50 The word 'rebuilt" has been abused and misused until it has become a meaningless trade term. 081r- iy-{Lrct When we rebuild a Fox Typewriter we take it allto pieces, re- nickel the nickel part s, ro- r., .,n, 3n, enamelthe frame and replace all worn parts with new ones. The same men who orig- -!*9j inally built the typewriter do this rebuilding and do the work just as good. 40% New Parts and Three Years' Guarantee We offer a rebuilt Fox Typewriter, Model No. 24 -Just like new -for $52.50. These have standard carriages, taking paper 101.4 inches wide, any kind of key- board, any kind of type, rubber covers, tabulators, back spacers, two-color rib- bons, complete with instruction books and cleaning outfits, and are guaranteed for 3 years, the same as new ones, and to have not less than 40% of new parts. Send any amount you can spare, from $1 up, as a first payment, and pay the balance $5.00 monthly. 5% discount for all cash. Purchaser must pay transpor- tation. If $10.00 or morels sent with order we will include FREE a Fox Solid Oak Typewriter Table selling at $4.50. Please order direct from this offer and inclose any Pay amount you can spare -and be sure and mention The Electrical Experimenter for March. $5.00 FOX TYPEWRITER CO., 8702 -8752 FRONT AVE., GRAND RAPIDS, MICHIGAN Monthly You benefit by menttontïig "The Electrical Experimenter" tchen writing to adzertsers. www.americanradiohistory.com 862 THE ELECTRICAL EXPERIMENTER March, 1917

5. GERÑSBACK t4. LESCI4RBOURt4 H.W.SECOR

This masterpiece contains 160 pages. 400 illustrations. Size The most comprehensive Wireless Course ever printed. Con- of book 5" x 9rt. Printed on extra thin paper, so book can tains 160 pages, 350 illustrations. Size of book 6 3/2tl x 9." be slipped in pocket. Handsome stiff cloth cover. Very fine flexible linen cover. Price $1.00 if bought alone. FREE with a year's subscription. Price $1.00 if bought alone. 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 by this liberal opportunity NOW; it may never be made again.

Subscribe to THE ELECTRICAL EXPERIMENTER for one year, at the regular subscription price of $1.50 per year (Canada and for- eign $2.00) and we will send you FREE POSTPAID, either one of 3 -17 the above books. If you subscribe for two years, BOTH BOOKS Gentlemen: GIVEN WILL BE. FREE, POSTPAID. P, Please enter my subscription If you are a subscriber at present, take advantage of this /,' to TUE ELEC- wonderful opportunity anyway. If you do, we will extend , TRICALEXPERI- your present subscription for one year. MENTER for the . LIGHtN J term of year..... MME TOÁRMa O,' which I enclose L ._ _ withfo You will also send me at once FREE nrenaid your hoots..

12 copies of THE ELECTRICAL EXPERI- EXPERIMENTER PUB. CO., MENTER make a book 9" x 12 "an4 4" thick. This book will weigh 7 lbs. It is the greatest 233 FULTON STREET, Electrical and Wireless reference @151st .s./ Name work in the world. And all for W ,/ NEW YORK CITY Address

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