3TORA Electrical Experimenter SCIENCE AND INVENTION
THE THOUGHT RECORDER
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Thousands of Electrical experts are needed to help rebuild the world. Come to Chicago to the great shops of Coyne and let us train you quickly by our sure, practical way, backed by twenty years of success. Hundreds of our graduates have become experts in less than four months. You can do the same. Now is your big opportunity. Come—no previous education necessary. Earn $125 to $300 a Month Day or Evening Courses Learn In the Electrical business. Come here where you will Don't worry about the money. Anyone with be trained in Drafting these great $100,000 shops. Experts ambition can learn here. Our tuition is low show you everything and you lea{n right on the ac- with small easy payments if desired. All tools The country is cry- tual apparatus. You work on everything from the and equipment is furnished free. Our students ing for skilled drafts- bell simple to the mighty motors, generators, electric live in comfortable homes in the best section men in ajl line's. Thou- locomotives, dynamos, switchboards, power plants, in Chicago—on the lake—just a few minutes' sands of positions open everything to make you a master electrician. We walk from our school. with princely salaries. have thousands of successful graduates. Just as soon We give you the ad- as you have finished we assist you to a good position. Electricity, Drafting vantage of our big shops. No other school Motion Picture Operating can do this. Now is Become an Expert in 33 2 Months the time to get into this big field. Experts No need of taking from 1 to 4 years to become an Plumbing train you under prac- expert, we have proved this in thousands of cases. tical working condi- The Coyne method of practical training eliminates We teach all these trades and professions in a thorough, practical tions, no books and all books, useless theory and other non-essentials and quickly and such way that finished are ready to step right theory go here. Check trains you in just what you need to know to become when you drafting on | into a position of responsibility and big pay. the cou- an expert. pon below and mail Earn Your Way it at once for full par- Send Today for Big Free Book ticulars. Don't tell yourself you haven't got the money to come to Coyne. If you have ambition and the nerve of a real man, Write today, now, for the book. It tells what that's <« all you need. Dozens of our students every year work Coyne graduates have done. What you in their spare time and earn their living expenses. Dozens of COYNE TRADE can do. Fill in the coupon, check the AND others work in the day time, earn all their expense and attend ENGINEERING SCHOOLS our evening school. Our employment department will help trade you are most interested in or ^ you without charge. ^ Bennett W. Cooke. Director send it a postal card, do now. Dept. 25. 39-51 E. Illinois St. BENNETT W. Director COOKE, ^ Chicago, III. Please send at once your big Free COYNE TRADE AND ENGINEERING SCHOOLS Book— I am interested in
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May. 1919 ELECTRICAL EXPERIMENTER iillllllllllilllitllllliiiiilllllllliiilllllllllllllllllllliiliiilll!lliiiiiiliillliiiiiiiiiiiiiiiiiiiiilliiiiiiiiiiiiiiiiililliiiilililiilllliliiilllllllllllllllllllliiiiiii!£
"See them E First — Pay E ELECTRICITY O, afterwards" = AS EXPERTS KNOW IT
Learn electricity a> you would in actual PRACTICE— in accordance with the methods employed bv the highest paid elec- trical experts in America. The New McGraw-Hill Library of Practical Electricity contains the actual working facts which you need in order to succeed in the electrical field. Ter- rell Croft, formerly with the Westinghouse Company makes the conquest easy for you.
A new standard in electrical literature The New Library of Practical Elec- tricity by Terrell Croft marks a new era in electrical literature. The great field of electrical engi- neering, with its limitless possibili- ties of earning power, is brought to you in a form that makes success Gentlemen: In an attempt easy. The Library to express myself about an CROFT^S NEW LIBRARY is a creation OF PRACTICAL ELEC- achievement that TRICITY, I have never is without parallel seen and do not believe there was ever in technical litera- printed in the English language, a ture, because it more comprehensive set of sticks to practice books. It is a library that throughout its is just as valuable to the novice as to the expert, be- 3000.pages. cause it is all practice. Respectfully, E $2 per month GVY H. PEIFER. £ starts you to Chief, Dopl.in Silk Cor- poration, H.izleton, Pa. E bigger pay. Croft's New Library of Practical Electricity. 8 vols. —3000 pages 2100 illustrations Now is the time to prepare for a high salary- -- Now is the time to master electricty.
Old books won't do. Amateurish books won't do. ; Not one cent in advance- E Books compiled by "desk authors" or men with no <*" E practical experience will not serve your purpose. Just the Coupon E Practical books are easiest mastered. Practical 2 books, written by practical men, teach you accurately Examine this new Library for ten full days without expense. Find out for yourself why it is now taking if E and rapidly. There is nothing in the Croft Library the lead in electrical book sales in America. Use the books as you see tit for ten days. Look at McGraw-Hill E which you cannot understand. Terrell Croft tells you the hundreds of illustrations that clear up all C° Book Co., Inc. the mysteries in electrical practice. Stick 239 W. 39th St.. - the secrets of success in electricity in plain words, fig- NEW YORK couple of the volumes in your pockets, and ures and illustrations. is left refer to them during the day. Figure out E Nothing to the imagina- $_ Gentlemen: in an instant the problems that have Please send me the Library E tion. There is no guesswork. There is no theory or heretofore taken hours. Practical Electricity (ship- 7 pinsping charges prepaid) for 10 E higher mathematics. free examination. If satis- Then send us $2 per month for factory. I will send %i In ten days Send now for these eight volumes. No matter how eight months, or return * and 5 2 per month until 116 has been entirely at our expense. If n it wanted I will writ© you E many books on electricity you possess, you are unfair risk nothing by returnin for return shipping Instructions. the attached coupon. = to yourself unless you take advantage of this free ex- E animation privilege. No matter whether you are be- E ginner or expert, these books will show you the clear ACT Home Address E road to success. Inspection will prove this. NOW Oily and State / Name nf I E 239 W. 39th St., New York. Your Position i iii ii ii i ii iii i ^miiiiiiiiiii iii limn i ii ii i ii iii iiiii in iiiii iii ill mi ii iii imiimi mi 4L You benefit by mentioning the "Electrical Experimenter" when writing to advertisers, perimenter 233 FULTON STREET, NEW YORK Publisht by Experimenter Publishing Company, Inc. ( H. Gernshack, President; S. Gernsback, Treasurer;) 233 Fulton Street, New York, Vol. VII. Whole No. 73 MAY, 1919 No. 1 THE THOUGHT RECORDER Front Cover RECLAIMING METAL DUST FROM FLUE GASES 26 From a painting by Howard Brown TRY THESE ON YOUR AUTO 27 FUTURE RAPID TRANSIT 7 THE TRUE WIRELESS—By Nikola Tesla.—Special Feature Article 28 WILL MAN FREEZE THE EARTH TO DEATH S AMPLIFIER BOOSTS SIGNALS 1,000,000 TIMES 31 By E. T. Brondsdon MULTIPLEX RADIO SYSTEM ADOPTED BY U. S 32 HOW THE FRENCH LOCATED SUBMARINES 9 NEW FRENCH AND AMERICAN AUDIONS 32 VEHICULAR TUNNEL UNDER THE HUDSON RIVER 10 NEW REGENERATIVE VACUUM TUBE CIRCUITS 33 By H. Winfield Secor By Samuel D. Cohen THE THOUGHT RECORDER—NO. 2 FUTURE INVENTIONS.. 12 PRACTICAL CHEMICAL EXPERIMENTS—TESTING OF WOOL, Bv H. Gernsback COTTON AND LINEN By Albert W. Wilsdon 34 PARIS LETTER, by Jacques Boyer, Paris Correspondent of the EXPERIMENTS IN RADIOACTIVITY. PART III 35 Electrical Experimenter 13 By Ivan Crawford LOCATING ENEMY GUNS BY FLASH AND SOUND 14 THE CONSTRUCTOR—THE "NOISELESS" PHONOGRAPH.... 36 NOVEL ELECTRICAL TALKING SIGN IS By Thomas Reed RELIEVING THE SUBWAY CAR CRUSH. By Sidney Gernsback 15 AUTOMATIC BELL RINGING ATTACHMENT FOR EIGHT DAY MY INVENTIONS, PART IV, by Nikola Tesla 16 CLOCK By T. A. Neelin 37 THE NEW YORK AERO SHOW 18 HOW-TO-MAKE-IT DEPARTMENT—PRIZE CONTEST 40 MONSTER ESCALATOR FOR NEW YORK SUBWAY 20 WRINKLES, RECIPES AND FORMULAS. Edited by S. Gernsback 42 BRITISH SUBMARINE LOCATER 21 LATEST PATENTS 43 PUTTING IT OVER ON FRITZ By K. K. Sammerin 22 WITH THE AMATEURS—LABORATORY ' PHOTO 'CONTEST .... 44 COLD LIGHT—WHAT IT IS By Rogers D. Rusk, M.A. 23 SCIENCE IN SLANG—THE SPECKS IN SPACE 45 POPULAR ASTRONOMY—ASTRONOMICAL DISTANCES 24 By Emerson Esterling By Isabel M. Lewis "THE ORACLE" 46 EDITORIAL Practlacal Science {HE wonderful age in which we are living perspiration soaks his clothing. Finally he sinks down has never been paralleled in history. We into the snow, exhausted, and if it is cold enough he is have more comforts, more conveniences, soon frozen stiff. Now Eskimos, who have learned a more of everything than human beings bit of science by hard experience, prefer to live pleas- ever had, since the creation of the world. antly thru the worst snowstorm, with the temperature Nevertheless, our lives become more and below zero. If the Eskimo becomes lost in the wilder- more complex, as time rolls on, while the ness he knows better than to run about aimlessly. He average human being becomes more perplexed at the promptly digs a cave into the snow, with the entrance strange surroundings in which he finds himself. away from the wind, using only his hands for tools. In- Our electro-mechanical age brings forth new sur- side of ten minutes he is safely ensconced in a com- prises constantly, and he who does not know the rudi- paratively warm shelter. He then closes up the entrance mentaries of mechanics, electricity and general physics almost entirely, sits down, drops his head on his knees, is like a blind man in a circus. He hears what is going and has a refreshing sleep. The next morning he digs on, but all is meaningless to him—he cannot get the full himself out, and is on his way. benefit of the performance. If the writer had not known something about elec- Where humanity now finds itself surrounded by ma- tricity, he, too, might not be here to write these lines. chines, and by electrical wires at every hand, it behooves As a boy he went down into an unoccupied cellar. The every man to know something about them. Thousands wind blew the wooden door shut, locking him in, as the of lives are lost even' year because laymen refuse to iron latch was outside. The only other exit was an learn a little about science in general. They get killed open window hole barricaded w-ith stout iron rods, because they fight short-circuits with water, when ten thru which the wind roared. The temperature was be- minutes of study would have told them that water is a low zero. The cellar was empty, save for a few wooden conductor, and that a few handfuls of dry sand—which crates, the object of the visit. The cellar being distant is a non-conductor—would have saved the life, and the from the house and other habitations, the parents away, house which burnt down due to the short-circuit. If and the caretaker off for the night, there was every pos- the father had told his boy that a wet rope is a good sibility of his freezing to death. No tools to break down conductor for electricity that boy would be alive today. the door, no matches to make a fire. But there was a Instead, the boy threw the wet rope over the high ten- portable light, with two large electric dry cells in a sion line, while holding it in his hand, and was killed. wooden box, which the writer had brought along to If the six hundred auto owners who were asphyxiated light his way. last year—the casualties become larger each year—had He unraveled the stranded electric cord and extracted known a bit of chemistry, they, too, would be living to- a single thin copper strand an inch long. With this he day. But they insisted upon running their engines in a short-circuited the dry cells. The wire became white garage with closed doors, and unfortunately, you can't hot. A piece of paper was touched to it, which burst is smell carbon monoxid, even if it deadly. into flame ; a broken piece of crate wood was ignited by Then, too, hundreds of people perish in snow storms the flame, and a fire soon roared. A burning crate set every year quite unnecessarily. Usually they freeze to the cellar door on fire, and in ten minutes the adventure death." The white man runs about in a frenzy when he had come to a close. knows himself lost. He becomes overheated, and the H. Gernsback. The ELECTRICAL EXPERIMENTER is publisht on the 15th of each month at 233' tions cannot be returned unless full postage has been included. ALL accepted contribu- Fulton Street, New York. There are 12 numbers per year. Subscription price 19 $2.00 a tions are paid for on publication. A special rate is paid for novel experiments; good year in U. S. and possessions. Canada and foreign countries, $2.50 a year. U. S. coin as photographs accompanying them are highly desirable. cents each. v.. 11 ,is,r. s. stamps accepted (no foreign coins or stamps). Single copies 28 ELECTRICAL EXPERIMENTER. Monthly. Entered as second-clasB matter at the A sample copv wiii be sent gTatis on request. Checks and money orders should be drawn New York Post Office under Act of Congress of March 3. 1879. Title registered IT 8 to order of EXPERIMENTER PUBLISHING CO.. INC. If you change your address Patent Office. Copyright, 1919. by E. P. Co.. Inc.. New York. The Contents of this mifirv us promptly, in order that copies are not miscarried or lost. A green wrapper In* magazine are copyrighted and must not be reproduced without giving full credit to the dlcates expiration. No copies sent after expiration. publication. The ELECTRICAL EXPERIMENTER Is for sale at all newsstands in the United States All communications and contributions to this journal should be addrest to: Editor, and Canada; also at Brentano's. 37 Avenue de l'Opera, ParlB. ELECTRICAL EXPERIMENTER, 233 Pulton Street, New York. Unaccepted contribu- Member of the Audit Bureau of Circulation. May. 1919 ELECTRICAL EXPERIMENTER The Secret of Being a Convincing Talker How I Learned It in One Evening By GEORGE RAYMOND AVE you heard the news about the loving cup the boys gave him, how flus- spoke clearly, simply, convincingly. Then came Frank. Jordan ?" tered I was and how I couldn't say a word be- my first promotion since I entered the account- there were people around? You remem- ing department. I was given the job of answer- H This question quickly brought cause ber how confused I used to be every time I ing complaints, and I made good. From that I little me to the group which had gathered met new people ? I couldn't say what I wanted was given the job of making collections. When in the center of the office. Jordan and I to say when I wanted to say it; and I deter- Mr. Buckley joined the Officers' Training Camp, had started with the Great Eastern mined that if there was any possible chance to I was made Treasurer. Between you and me, learn how to talk I was going to do it. George, my salary is now $7,500 a year, and I Machinery Co., within a month of each "The first thing I did was to buy a number expect it will be more from the first of tie year. other, four years ago. A year ago Jor- of books on public speaking, but they seemed "And I want to tell you sincerely, that I dan was taken into the accounting divi- to be meant for those who wanted to become attribute my success solely to the fact that I sion and I was sent out as salesman. orators, whereas what I wanted to learn was learned how to talk to people." ******* not only how to speak in public but to Neither of us was blessed with an un- how speak to individuals under various conditions When Jordan finished, I asked him for the usual amount of brilliancy, but we got in business and social life. address of the publishers of Dr. Law's Course by in our new jobs well enough to hold "A few weeks later, just as I was about to and he gave it to me. I sent for it and found them. give up hope of ever learning how to talk in- it to be exactly as he had stated. After study- terestingly, I announcement stating ing the eight simple lessons I began to sell to Imagine my amazement, then, when read an that Dr. Frederick Houk Law of New York people who had previously refused to listen to I heard: University had just completed a new course me at all. After four months of record break- "Jordan's just been made Treasurer in business talking and public speaking entitled ing sales during the dullest season of the year, of the Company!" 'Mastery of Speech.' The course was offered I received a wire from the chief asking me to on approval without money in advance, so return to the home office. We had quite a long I could hardly believe my ears. But there since I had nothing whatever to lose by exam- talk in which I explained how I was able to was the "Notice to Employees" on the bulletin ining the lessons, I sent for them and in a few break sales records—and I was appointed Sales board, telling about Jordan's good fortune. days they arrived. I glanced through the Manager at almost twice my former salary. Now I knew that Jordan was a capable fel- entire eight lessons, reading the headings and I know that there was nothing in me that had low, quiet, and unassuming, but I never would a few paragraphs here and there, and in about changed except that I had acquired the ability have picked him for any such sudden rise. I an hour the whole secret of effective speaking to talk where formerly I simply used "words knew, too, that the Treasurer of the Great was opened to me. without reason." I can never thank Jordan Eastern had to be a big man, and I wondered "For example, I learned why I had always enough for telling me about Dr. Law's Course how in the world Jordan landed the place. lacked confidence, why talking had always in Business Talking and Public Speaking. Jor- The first chance I I into got, walked Jor- I seemed something to be dreaded whereas it is dan and are both spending all our spare time dan's new office and after congratulating him really the simplest thing in the world to 'get up making public speeches on war subjects, and warmly, I asked him to let me "in" on the and talk.' I learned how to secure complete at- Jordan is being talked about now as Mayor of details of how he jumped ahead so quickly. tention to what I was saying and how to make our little town. His story is so intensely interesting that I am everything I said interesting, forceful and con- going to repeat it as closely as I remember. vincing. I learned the art of listening, the value So confident is the Independent Corporation, "I'll tell you of silence, and the power of brevity. Instead publishers of "Mastery of Speech." Dr. Law's just how it Course happened, of being funny at the wrong time, I learned in Business Talking and Public Speak- how and when to use humor telling ing, that once you have an opportunity to see George, be- with effect. "But perhaps the most wonderful thing about in your own home how you can, in one hour, cause you may learn the secret of speaking and how you can pick up a the lessons were the actual examples of what things apply the principles of effective speech under pointer or to say and when to say them to meet two all conditions, every condition. I found that there was that they are willing to send that will a help you the free knack in making oral reports to my superiors. Course on examination. you. Don't I found that there was a right way and a send any money. Merely mail the "You re- coupon or wrong way to present complaints, to give esti- write a letter and the complete member how will mates, and to issue orders. Course be sent, all charges prepaid, at scared 1 used once. If you are not entirely satisfied send it to be when- "I picked up some wonderful pointers about back any time within five days after you re- ever I had to how to give my opinions, about how to answer ceive it and you will owe nothing. talk to the complaints, about how to ask the bank for a FREDERICK HOUK LAW On the other hand, if you are as loan, about how to ask for extensions. pleased as As educator, lecturer, execu- chief? You Another are the thousands of other men and women tive, travtler and author few remember how thing that struck me forcibly was that, instead men are so well equipped by who have used the Course, send only SS in you used to of antagonizing people when I didn't agree experience and training as Dr. full payment. You take no risk and you have Law to teach art of effec- with them, I learned how to bring them around the tell me that everything tive shaking. Bis "Mastery of to gain, so mail the coubon now every time I to my way of thinking in the most pleasant Speech" is the fruit of 20 years' before this remarkable offer is withdrawn. active lecturing and instruction opened my sort of way. Then, of course, along with those in Eastern schools and colleges mouth I put lessons there were chapters on speaking before FREE EXAMINATION COUPON preceded by an education at Oxford Academy. Amherst Col- my foot into large audiences, how to find material for talk- University. lege. Columbia The it, meaning of ing and speaking, how to talk to friends, how Brown Uni- Teachers College. to talk to servants, and how to talk to children. Independent Corporation versity, and New York Univer- course that sity. He holds the degrees of every' time I "Why, I got the secret the very first evening Publishers of The Independent Weekly A.B.. A.M.. and Ph.D. spoke I got in- and it was only a short t : me before I was able Dept. L-1105 119 West 40th Street, Dr. Law Is the author of two New York to trouble ? You to apply all of the principles and found that novels, two books of poetry, and Please send me Dr. Frederick Hnuk Law's "Mas- editor of six school text-books. remember my words were beginning to have an almost tery of Speech." a Course in Business Talking and At present he is lecturer in I Public Speaking in eight lessons. I will either English in New York University. when Ralph magical effect upon everybody to whom re- ma II the Course to you within Are days after Its Lecturer in Pedagogy in the left spoke. It seemed that I got things done in- Sinton to receipt, Extension Work of the College or send you $5. take charge of stantly, where formerly, as you know, what I of the City of New York. Head of the Dept. of English in the the Western of- said 'went in one ear and out the other.' I be- Name Stuyresant H. S. and writer fice and I was gan to acquire an executive ability that sur- of the Weekly Lesson Plans for The Independent. asked to pre- prised me. I smoothed out difficulties like a sent him with true diplomat. In my talks with the chief I Elect. Exp. 5-l» You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. ELECTRICAL EXPERIMENTER May, 1919 >Vl^^l^^^^^t^^t\Wi>sqi\gqwqi)sqi^wq The Burgess BLUE BOOK for all Practical Men and Electrical Students (.See review of this book by Editor in December issue of your Electrical Experimenter page 568) I have prepared a pocket-size note book especially for the practical man and those who are taking up the study of elec- tricity. It contains drawings and diagrams of electrical ma- chinery and connections, over two hundred formulas for calculations, and problems worked out showing how the formulas are used. This data is taken from my personal note book, which was made while on different kinds of work, and I am sure it will be found of value to anyone engaged in the electrical business. i The drawings of connections for electrical apparatus tions, Calculating Unknown Resistances, Calculation of include Motor Starters and Starting Boxes, Overload Current in Branches of Parallel Circuits, How to Figure and Underload Release Boxes, Reversible Types, Eleva- Weight of Wire, Wire Gauge Rules, Ohm's Law, Watt's tor Controllers, Tank Controllers, Starters for Printing Law, Information regarding Wire used for Electrical Press Motors, Automatic Controllers, Variable Field Purposes, Wire Calculations, Wiring Calculations, Illu- Type, Controllers for Mine Locomotives, Street Car mination Calculations, Shunt Instruments and How to Controllers, Connections for Reversing Switches, Motor Calculate Resistance of Shunts, Power Calculations, and Dynamo Rules and Rules for Speed Regulation. Efficiency Calculations, Measuring Unknown Resis- Also, Connections for Induction Motors and Starters, tances, Dynamo and Dynamo Troubles, Motors and Delta and Star Connections and Connections for Auto Motor Troubles, and Calculating Size of Pulleys. Transformers, and Transformers for Lighting and Power Also Alternating Current Calculations in finding Im- Purposes. The drawings also show all kinds of light- pedance, Reactance, Inductance, Frequency, Alterna- ing circuits, including special controls where Three and tions, Speed of Alternators and Motors, Number of Four Way Switches are used. Poles in Alternators or Motors, Conductance, Suscep- The work on Calculations consists of Simple Electri- tance, Admittance, Angle of Lag and Power Factor, and cal Mathematics, Electrical Units, Electrical Connec- formulas for use with Line Transformers. WHAT PRACTICAL MEN SAY ABOUT THE "BURGESS BLUE BOOK" Received your "Blue Book" and must say it is the best book licate their order to you. Go ahead with this good work. 1 ever saw. I showed it to a friend of mine and he refused to Yours truly, give it back to me but he paid me a dollar and told me to get EDW. C. RAY. another. Rather than be without this book 1 am sending Money Brooklyn, New York. Order for three of them so 1 can show them to two more of my friends and have left for would one myself. Wishing you mail I am enclosing three dollars for which please send me three at once. them I am Yours very truly, copies of the "Burgess Blue Book". 1 showed the copy 1 got JOSEPH BRAITH, Electrician. last wee!: to some friends and three of them asked me to get Madison, Wisconsin. them one. Very truly yours, CHAS. H. DAVIS, Your "Blue Book" received and it is just the book I have Los Angeles, Cal. been looking for. Please mail me three more by return mail for which I am enclosing Money Order. Respectfully, I received your "Blue Book" and after I looked over it 1 see V. E. Tel. Co.. JOHNSON, Western Union that it is a very useful book. After 1 showed it to some fellows Marion, Ohio. they wanted a copy also and 1 am enclosing Money Order for which please send me three at once. Yours very truly, Have received the copy of the "Burgess Blue Book" and am very well pleased with the easily found formulas and data con- R. S. SWANSON, St. Paul. Minn. tained in it. 1 am enclosing Money Order for four additional copies. Very truly yours, I received the three books I for I sold THURE C. ANDERSON, sent and the next day Ridgeway, Penn. them. The fellows think they are well worth the price. Please send me three more for which 1 am enclosing Money Order. Yours very truly, Dear Sir: —There can be no possible question as to the ser- vice you are rendering Electrical Workers. To date 1 have R. S. SWANSON, received 78 Burgess Blue Books and hope my friends will dup- St. Paul, Minn. NOTICE To help get the "Burgess Blue Book" to the men who need it the most, we have established a resale discount to which those who have purchased a book from us are entitled. In this way the "Blue Book" is sold by those who know its value and we feel that this arrangement is much more satisfac- tory to the purchaser, than if he bought it through the regular book-selling channels. The book practically sells on sight, as a man engaged in practical work realizes when he sees it, it contains infor- mation which is extremely useful and which is difficult to obtain. The Burgess BLUE BOOK Will Be Shipped, Postpaid, on Receipt of $1.00 Send dollar bill, money order or check. / guarantee satisfaction or will return your money if you decide not to keep the hook after using it for five days BURGESS ENGINEERING CO., ££SS2 "TSSJXZ You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. — May. 1919 ELECTRICAL EXPERIMENTER Was $100 The Famous Oliver For Free Trial—Then Save $43 This is the identical $100 Oliver, you merely pay $3 per month un- Model 9, our latest and best. We til the $57 is paid. This is less than continue to sell it under the plan 10c per day. we adopted during the war. This Oliver is being bought by We learned economies then in the thousands. Our plan, con- selling which enable us to save the ceived when this country entered $43 it formerly cost us to sell you the war, has met a tremendous an Oliver. welcome. We have repeatedly in- We learned that it was unneces- creased our production facilities sary to have great numbers of Note at the left a few of the great traveling salesmen and numerous, concerns using the Oliver. And re- expensive branch houses through- member that it is being bought by ramous users out the country. We were also thousands of individuals. It has able to discontinue many other been aptly called the people's type- superfluous, costly sales methods. writer. Tn every particular, this splendid You benefit by these savings. U. S. Steel Corporation Oliver is the finest that 24 years of Only our sales plan has changed. experience can produce. A better type- Not the Oliver. Our new plan is writer is impossible. It has all the latest improvements. It is noted for Pennsylvania Railroad to ship direct from the factory to its handsome appearance, richly enam- you, depending upon the Oliver to eled olive green and polished nickel; Nat'l City Bank of New York be its own salesman. its durability and workmanship. Do you know of any typewriter which may order direct from this You combines so many advantages, yet Morris & Company advertisement, without sending a offered at such a low price and easy penny. The coupon brings an terms? This Oliver has a standard key- Oliver for free trial. Encyclopedia Britannica board. So anyone may turn to it When the Oliver comes to you, without the slightest hesitancy. It is let it prove its superiority and speedy and has an untiring action with lightest touch. Boston Elevated Railways saving. You be the judge, with no Don't buy—don't rent—until you eager salesman present to influence have investigated this fine economical Otis Elevator Co. you. Oliver. Note that the coupon below brings either an Oliver for Free Trial, If not agree that it is you do or further information. Corn Products Refining Company the finest typewriter built, regard- less of price, simply return it, ex- Canadian Price, $72 press collect. Even the outgoing Columbia Graphophone Co. transportation charges will then be The Oliver Typewriter Co. refunded. N. Y. Edison Co. The Oliver for $57 makes a $100 675 Oliver Typewriter Bldg. price appear extravagant. Chicago, Illinois Hart, Schaffner & Marx Remember this is not a second-hand or rebuilt THE Diamond Match Co. machine. If any type- OLIVER TYPEWRITER COMPANY 675 Oliver Typewriter Building, Chicago. III. writer is worth SI 00, it Ship Hi,- a in u- Oliver Nine for five davs free insi ec- is this brand new Oliver. i I will Baldwin Locomotive Works I pay (57 at the rat* or $3 Furthermore, it is as nih The title to remain In jmmi until fully paid for, My shipping imiiii is Oliver easy to buy The i does ii.-i place me uiuier any obligation to buy. 11 I American Bridge Co. tu tin- Oliver, I will ship it back at your as it is to try it. If, . choose return expense ;ii tin- end ol 5 days. after trying it five days l>u in. I semi ii niai hinc until I order it. Mail me your honk- "Tii.' High Cost of Typewriters—The Reason you decide to keep it, and the Remedy." your do luxe catalog and further in- formal li Over 700,000 Sold Name Save $43 by using Street Address this coupon (4.02) City State Occupation or Business You benefit by mentioning the 'Electrical Experimenter" when writing to advertisers. ELECTRICAL EXPERIMENTER May, 1919 Master Electricity By Actual Practice The only way you can become an expert is by doing the very work under competent instructors, which you will be called upon to do later on. In other words, learn by doing. That is the method of the New York Electrical School. Five minutes of actual practice properly directed is worth more to a man than years and years of book study. Indeed, Actual Practice is the only training of value, and graduates of New York Electrical School have proved themselves to be the only men that are fully qualified to satisfy EVERY demand of the Electrical Profession. The Only Institution of the Kind in America At this "Learn by Doing" School a man acquires the art of Electrical Drafting; the best business method and ex- perience in Electrical Contracting, together with the skill to install, operate and maintain all systems for producing, transmitting and using electricity. A school for Old and Young. Individual instruction. Over 5,500 Graduates are Successful Men in the Electrical World No previous knowledge of electricity, mechanics or mathematics is necessary to take this electrical course. You can begin the course now s:sssssSSs::: and by steady application prepare yourself in a short time. You will be taught by practical electrical experts with actual apparatus, under actual conditions. Let us explain this course to you in person. If you can't call, send now for 64-page book— it's FREE to you New York Electrical School 29 W. 17th St., New York, N. Y. Please send FREE and without obligation to New York me your 64-page book. (NAME) _ Electrical School (ADDRESS) 29 West 17th Street, New York ELECTRICAL EXPERIMENTER H.GERNSBACK - EDITOR HW.SECOR -ASSOCIATE EDITOR No. 7:5 Vol. VII. Whole \l VY, 1919 \... 1 FunttoniFe Rapid Tir&inisM PEOPLE who have traveled abroad interesting suspended railway in the motion monorail car, which might be termed an will remember having seen the re- picture travelogues given by Burton Holmes. 'Aerial Monoflicr," and which has been re- markable suspended aerial railway of It has always seemed to us, however, that cently invented and patented by the cele- Elberfeld (Germany J, the cars hav- these cars have a little too much freedom brated French engineer, M. Francis Laur ing wheels on the roof instead of of movement to make the ride as com- of Paris. As M. Laur points out in his underneath, and but one rail being used. fortable as it might be to the passengers, description of the invention, his scheme re- This form of construction gives, among owing to the constant swinging or side- lates to an improvement in a vehicle for other considerations, much greater flexibil- wise rolling motion produced by this cradle use in high speed locomotion in connection ity to the speeding cars or trains, as for suspension arrangement. Apparently there with a monorail or single track. A very example when they wish to turn sharp are other people who have entertained sim- novel idea of the project is a passenger- curves at comparatively high speed. Pos- ilar ideas, for in the accompanying illustra- carrying vehicle somewhat in the form of sibly many will remember having seen this tion there is shown a new development of a (.Continued on page 66) OvpsTlshl. IMS. b> E t CO Th Aerial Monoflier of Tomorrow—Equipt with Like .f Wings, an Airplane, It Will Skim Along Thru the Air. Guided by the Mono- rail. The Cars Are Propelled by Motor-Driven Propellers. Which Derive Their Power from Third Rails, as the Car Glides Along at Speeds of 200 to 300 Miles Per Hour. When in Motion the Entire Weight Is Practically Carried by the Wings, the Same as in an Airplane. — — ELECTRICAL EXPERIMENTER May, 1919 111 Msie iy E. T. BIROHDSDOH VO RENT : Ten-room suburban urday afternoon. Then there would be the ject unless a dynasty of scientific Methuse- home. Three baths. Sun, sleeping greatest point of all. Once installed, this lahs is established. and breakfast porches. Radium radium system never would have to be The one big obvious objection at present 1 i ." lies heating system (20 pounds) . . replaced! When one house began to dis- to the use of radium for heating plants To find this advertisement, look in integrate from old age, the mysterious in the scarcity and tremendous cost of the the classified columns of any metropolitan metal could be taken out and installed in metal. One ounce only would cost, at the newspaper five or six centuries hence. Our the system of a new house, and so on for- present market price, approximately $40,000. great-great-grandchildren fifteen times re- ever, unless some careless janitor took it The twenty pounds necessary for heating moved will be worrying about paying the out to clean and left it in the subway the ten-room house mentioned would retail rent on some such dwelling. Have you Coal men and ash carters would pass into at $12,800,000, were such a quantity pro- paid your "Radium Rent" will be a common that same merciful oblivion which shelters curable. Figuring interest at six per cent, slogan then. stage-coach bandits and Indians on the war- the cost of that radium heating system for Radium power, light and heat for apart- path. a year—excluding the original investment, ment and home will seem as much of a The reason why such a radium system which would not appreciably deteriorate commonplace to them as soft coal furnaces would never have to be replaced is that would be in the neighborhood of $768,000, seem to us. In tomes of ancient history they radium is the one and only close approach or about 4,000 times the cost of coal heat- will read stories of how their ancestors to perpetual motion to be found on our ing today. struggled thru the smoky winter of 1918, globe. Look at a piece of radium one- The only logical reason in the world for and they will marvel at our lack of under- thousandth the size of a pin point thru a even allowing imagination to roam on this standing. Soft coal then will have a place' spinthariscope. This is an instrument con- subject lies in the terrible and undisputed only in museums. sisting of a high-magnifying lens and an fact that somewhere we are going to haze Twenty pounds of radium gives off an aluminum disc covered with zinc sulfid. to get heat if we are to li:e! amount of heat in six months equivalent to When viewed in this manner millions of So much space has been given in the last that secured by burning four and one-half tiny arrows of fire are seen to be Hying decade to learned dissertations on our tons of the best Pocahontas or anthracite from the radium and impinging on the zinc rapidly decreasing supplies of coal and coal. The ten-room house mentioned above sulfid with an explosion like that of a fire petroleum that it is useless to dwell on this. would be adequately heated, however, on ball from a Roman candle. Suffice it to say that the last reports of twenty pounds, because a radium heating Tho each of the exploding projectiles of competent authorities state baldly that we plant would be one hundred per cent effi- helium—radium somehow transforms itself will surely be out of both forever at the cient. Even with hot water and hard coal into active atoms of this other element conclusion of the present century, provided from eighty to ninety per cent of the heat looks nearly as large as the original divot our present rate of consumption is neither our plants generate goes up the chimney. of radium, you may glue your eye to the raised or lowered. Since we have no assur- A radium system would have no chimney. spinthariscope for hours—centuries, if you ance that the rate of increase of consump- Every single heat unit would be conserved live that long—and you never will see any tion will not keep on, we may bet safely for the interior of the house and distributed diminution in the discharge or in the size of that the year 1975 will see coal and oil so by any ordinary medium, such as register, the radium piece.* Scientists who have scarce that only millionaires can afford radiator or the like. given the matter intensive study over long them. Coal then may be $500 a ton, and In addition to this, the radium system months and years say that they suspect crude oil $25 a gallon. Alas for the would have the splendid recommendatio-i radium of losing an infinitesimal part of its "flivvers"! Imagine Mr. Autoist of that day HIGHLY HEATED, ALTHO JTHE EARTHS RADIUM ^SUPPLY IS SCATTERED SOLID ZONE, 80 MILES JNCIPALLY THRU A IN DEPTH, CONTAINING ' MILE CRUST SLIGHT AMOUNT OF RADIUM 3 MILE DEPTH OF EARTH"S CRUST: PROBABLE LIMIT OF MAN'S RADIUM EXTRACTION Radium Power, Light and Heat for Apartment and Dwelling Will Seem as Much of a Commonplace to Those of Future Generations as Soft Coal Furnaces Seem to Us. In Tomes of Ancient History They Will Read Stories of How Their Ancestors Struggled Thru the Smoky Winter of 1918, and They Will Marvel at Our Lack of Understanding. All Be- cause of the Wonderful Power of "Radium" to Give Off En- ergy—Convertible Into Heat, Light, and Power, for a Practi- cally Indefinite Period. At Any Rate for Thousands of Years. So the Principal Problem We Have to Solve Is—How to Find a Far Cheaper Way to Remove the Radium Than We Have at Present. And Why Should We Do This? Because, as Mr. Brondsdon Points Out, the Coal Supply of the World Is Fast Giving Out. On the Other Hand, Man Must Not Remove Too Much Radium from the Earth or the Earth May Freeze to Death. Copyright. 1919. by E. that there would be no flues, traps or pipes actual weight in the course of a few eons, going into the garage and asking for a new to be cleaned, and no ashes would accumu- but that human beings are going to have "can" of Radium for his "Radiobile." It late to make the householder angry on Sat- trouble gathering accurate data on the sub- can happen. (Continued on page 59) ^This is not strictly the case, for the zinc sulfid spinthariscope we have to-day. for while the radium will last for thousands of years, the zinc sulfid will give out in a relatively short time. However, there are undoubtedly other substances which would last much longer than zinc sulfid. Another variable factor, variable in the sense that we have not lived long enough with radium yet to tell exactly how long if will last before losing its power, is the total life of this marvelous substance. Scientists tell us that in 1,800 years radium loses one-half of its activity. In another 1,800 years one- half of the remainder will have disintegrated, etc., etc. So that on this assumption the radium will have totally disintegrated in 22,000 years.— Editor. a May, 1919 ELECTRICAL EXPERIMENTER Mow tllhie Fireimclhi Located by one the multitudinous sci- depending upon the operating conditions in/id as the must improved type and most ONEentific secret! of tin- great World and the size of the submarine. practicable. War an- finding t lit- i r waj t" llif The Walser Gear, whose construction has The sounds are received thru a number public press, so thai the student been kept secret during the war, is a direc- Hi vibrating diaframs fitted into i in i ience maj at last have lii^ ap- tional apparatus for detecting and recording id a "blister" of *hect petiti ! in Ins <|iii->t nt descriptive Sounds heard thru water and tlui- locating steel, which replaces a curr- Photos International Film Service The Walser Gear—a Type of Hydrophone Used for Submarine Listening. The Walser Gear, Whose Construction Had Been Kept Secret During the War, is a Directional Apparatus for Detecting and Recording Sounds Thru Water and Thus Locating the Presence or Approach of Enemy Ships. This Apparatus is the Invention of Lieut. Georges Walser, of the French Navy, and is Recognized as the Most Improved Type and Most Practicable. The Sounds are Received Thru a Number of Vibrating Plates Fitted Into Holes Pierced in a Boss, or "Blister" of Sheet Iron, Which Replaces a Corresponding Section of a Ship's Hull. The Observer Works in a Sound Proof Cabin Stretching Across the Whole Width of the Ship, and Wears a Listening. helmet, Attached to Two Trumpets. Into These Trumpets the Sounds are Focused By the Vibrating Plates Attached to the "Blister." Left: — Detecting the Presence of Enemy Ships On or Under the Surface of the Sea. An Observer Using the Walser Gear in a Special Cabin Fitted Up as a Listening Post. Right:—On the Hull of the "Henriette II". a French Warship Which is Using the Apparatus, Showing the Exterior of the Sound—Collect- ing Boss or "Blister". matter on some of the master problems the presence or approach of enemy ships. tion of a ship's hull. The observer works which have been worked out and solved Many different devices for "listening" for in a sound-proof cabin stretching across the by engineers and scientific workers con- enemy ships have been disclosed, but this whole width of the ship, and wears a listen- nected with army and navy developments. apparatus, the invention of Lieut. Georges ing helmet attached to two trumpets. Into Probably no one problem in the whole war Walser, of the French Navy, is recog- these trumpets the sounds are focust by drew more attention from laymen and the vibrating diaframs attached to the scientists alike than did the one of _ the "blister." accurately discovering and locating the To ear pea Some of the disadvantages of the whereabouts of the Kaiser's U-Boats. ordinary listening microphone arrange- The United States Xaval Advisory ment for the detection of submarines Board received thousands upon thou- are the following : Invariably the ves- sands of suggestions, all telling how sel on which they are mounted has to very simple it was to ferret out and be stopt momentarily while a listening locate the position of an enemy sub- test is being made, in order that the marine, just by placing a microphone ship's engines shall not drown out the or set of microphones in the hull of a sounds which the listening operator is vessel and connecting these up with a endeavoring to pick up from the sea. set of telephone receivers, so that the It is interesting to mention in this con- sound produced by the submarine pro- nection, that some of the American peller and motor would be picked up listening devices of this type were so by the microphones and thus heard in remarkably sensitive that even a small the receivers. Various methods were dynamotor used on the regular wire- described for taking certain definite less apparatus on the vessel had to be and very precise measurements along mounted on springs, so that the ex- these lines, so as to work out mathe- tremely slight mechanical vibration set matically or otherwise the position of up by it would not interfere with the the lurking sub-sea fighter. Consider- sounds picked up from the water on the able success was obtained with similar submerged microphones fastened to the arrangements \ : the navies of the dif- hull of the boat. Another fault found ferent countries participating in the with the ordinary "hydrophone" is that World War, but the Walser gear— the different sounds received simulta- special type of hydrophone used par- ScnS'tire Vtbrot/ng neously could not be distinguished very P .-,VS ticularly for listening to submarines readily from one another, and even if tcoust/c-iens under water was developed and success- but one sound was picked up. the di- fully used by the French Navy and rection from which the sound ema- other allied vessels for accurately lo- Diagram of One "Lens" of the Walser Submarine nated was not very perfectly indicated. Detector and Locater, Showing the Carefully Worked at one of the cating enemy submarines distances Out Balancing Scheme for Supporting the Movable Practically speaking then, of one mile to three miles or more, Sound Trumpet Over the Various Sound Focal Points. (Continued on fag 10 ELECTRICAL EXPERIMENTER May, 1919 The Accompanying Sectional View Shows Vividly How the New Vehicular Tunnel Under the Hudson River at New York City Will Look When Finished. There Seems to be No Question at Present as to the Possibility of Building This Tunnel, and the Only Remaining Details Are Engineering Considerations Such as Ventilation, Etc., Which Are Being Rapidly Solved by Some of the Crack Engineers of America, Including No Less a Personage Than General George W. Goethals, Builder of the Panama Canal, and Now Holding the Position of Con- sulting Engineer to the Interstate Bridge and Tunnel Commissions of New York and of New Jersey. Several Other Proposals Have Been Brought Forward for the Building of This Tunnel Under the Hudson River, But the Goethals Plan Seems to be the Most Feasible, and the One Most Likely to be Adopted. The Length of This Vehicular Tunnel Will be About 9,400 Feet from Portal to Portal, with a Distance of 5,500 Feet, or More Than a Mile Separating the Bulkhead Lines, if These Are Placed Back of the Shore Line. In View of the Fact that the Ventilation Problem is at Present One of the Most Important, and the One Responsible for the Most Discussion Among Tunnel Experts, We Have Several Suggestions in the Present Article and Illustrations Which Might, if Adopted, Help to Bring About the Early Adoption bridging of the Hudson River, THEcommonly known as the North River in New York City, is an engineering .©mi mv problem that has been before the people of the states of New York and New Jersey for probably more than thirty By H.WINFIELD this great water years. A bridge across Associate Member American highway would no doubt have been con- structed many years ago, if it had been found possible to raise sufficient funds to neer of the Public Service Railway Com- one line of traffic apportioned to gasoline render this dream a living reality. Engi- pany of New Jersey, the ventilating prob- vehicles on each roadway, and having the neering experts have recently bestirred lem of such a tunnel as proposed by Gen- owners of these vehicles equip them with a themselves with the thought of crossing the eral Goethals and other engineers can be trolley pole, but by the time the owners had Hudson either by bridge or else by means readily taken care of, as actual laboratory installed an electric motor under the gaso- of a tunnel, particularly a vehicular tunnel tests have proven, and which have provided line vehicles for use with it, it would prob- suitable for horse-drawn, electric and gaso- a satisfactory basis for calculating the re- ably be just as well for the tunnel operating line propelled vehicles. The bridge ques- sults of such a long tunnel as that under the engineers to ask the owners of such vehicles tion seems to have been discarded prac- Hudson. Also to back up the argument to invest in electric trucks for that par- tically altogether now, owing to its tremen- for building the tunnel, there is precedence ticular traffic intended to go via the tunnel. dous initial cost, which would be about afforded by the fact that London, England, All of the tunnel proposals now under $72,000,000 at least, compared to the initial has built two vehicular tunnels under the consideration agree on the location, which cost of $12,000,000 for constructing a large Thames River, one 6,200 feet long, and the extends from Twelfth Street, Jersey City, tunnel under the Hudson on the newly re- other 6,883 feet long. to Canal Street, New York. The termini vised plan proposed by General George W. The editors make several new tunnel of the tunnel at both ends are located in the Goethals, the well-known American engi- suggestions, which are shown in the illus- center of the trucking and freight dis- neer and builder of the Panama Canal. tration accompanying this article, whereby tricts. The New Jersey terminus is also General Goethals has been appointed con- the gigantic ventilating problem could be happily located adjacent to the great freight sulting engineer to the Interstate Bridge overcome to a large extent by controlling yards of the principal railroads, and close to and Tunnel Commissions of New York and the kinds of traffic that should be allowed to the main ferry lines, thus providing every of New Jersey. There are many reasons pass thru the tube. First, the writer would chance for close co-operation. Besides, the why New York should have means of com- suggest that the engineers contemplating the great Lincoln and other much used vehic- munication such as this, as its sister state building of this tunnel consider a cable-way, ular highways lead to the location proposed supplies, either directly or indirectly, a very one of which would be provided on each for the Jersey City terminus. large portion of the food and other com- roadway, east and west, for the purpose of The Hudson tubes as well as the Penn- modities for greater New York's population hauling gasoline operated vehicles thru the sylvania tunnels under the Hudson River, of 7,000,000, which is brought to the piers tunnel, without their engines being operated. which are used for railway traffic exclusive- on the west side of the Hudson by numer- thus doing away with the production of the ly, were driven by the well-known shield ous railroads. Right here there is a con- objectionable carbon monoxid and other method. General Goethals, in his proposal stant and prohibitive wastage of perishable poisonous gases emanating from their ex- for the new Hudson vehicular tunnel, has food products, owing to the highly con- haust. It would not be an impossible, or advocated the shield-driven double-deck gested and inadequate terminal facilities af- even impracticable matter, if such an elec- single tube, as shown in the accompanying forded for their movement. tric motor-operated cable-way, similar to illustration. This tube is to have an internal At the present time there is more or the old cable-car systems, were used to haul diameter of 36 feet, with two 18-foot road- less agitation in the legislatures of both the gasoline vehicles thru the tunnel to Jer- ways, one super-imposed above the other, states between those friendly and unfriendly sey or to New York. It could be arranged and a concrete floor between them. This to the Hudson River project. So far the to have the owners purchase a standard proposal for the tunnel would permit of one great problem, according to some of the cable grip, which could be fitted on to any four lines of vehicles, two on each roadway, testimony being given, and which has gasoline vehicle at nominal cost. two of the faster moving type such as seemed almost insurmountable, is the proper Another proposal, made by Mr. H. Gerns- pleasure automobiles on the upper floor, ventilation of this tube, especially where back, is one employing a moving roadway and two of the slower moving vehicles, such gasoline driven vehicles are to be permitted of sufficient width to accommodate gasoline as auto-trucks, on the lower floor. to exhaust devitiating gases into the air of auto trucks, the roadway being operated by Most of these under-river tubes have been the tunnel. But according to a very able electric motors spaced at suitable intervals constructed with cast-iron blocks built of engineering report on this project, given in along its length. segmental form, which were bolted together the Journal of the Franklin Institute and Another proposal suggested by the writer after being put in place, and which thus prepared by Martin Schreiber, Chief Engi- would be to utilize a trolley wire over the tended to resist any external hydrostatic : ELECTRICAL EXPERIMENTER of the Tunnel Project. Among These Features Are the Following: — First, That a Ventilator Shaft be Placed a Comparatively Short Ways Out in the River at Either Approach, So as to Simplify the Ventilating Problem by Reducing the Length Between the Bulkheads. Second, That Gasoline Vehicles be "Hauled" Thru the Tunnels So as to Elim inate the Fouling of the Air by Obnoxious Exhaust Gases. Particularly Carbon Monoxld, by Means of a Moving Platform. Third, Haul Gasoli ne Vehicles Thru the Tunnel by a Cableway Similar to the Weil-Known Cable Car System. Fourth, Cause the Gasoline Vehicles to be Fitted with a Trolley Pole and Electric Motor for the Purpose of passing Thru the Tunnel Without Discharging Obnoxious Gases. The Goeth als Proposal Calls for a Concrete Block Tunnel, 42 Feet In Outside Diameter, with Two Road Levels, as Here Shown. One Roadway Will be for East-Bound Traffic, and the Other for West-Bound Traffic. Actual Laboratory Tests On a Short Length of Tunnel Have Shown That 750 H.P. Would be Required to Operate the Fresh Air and Ex- haust Fans, with a Maximum Capacity of 360,000 Cubic Feet of Fresh Alr Per Minute. cars had been running light for forty min- 5 utes, the condition of the atmosphere was 'JhicMlair H\iimiime]l almost normal, so far as physiological action was concerned, and the amount of carbon monoxide content not dangerous SECOR This calculation was further supported by the fact that eighteen persons who re- Institute Electrical Engineers mained in the tunnel during the test for a continuous period of forty minutes expe- pressure with great power, much in the the Pennsylvania tunnel shields 23 feet 6 rienced no unpleasant sensations from same way that the stones of an archway inches. The latter were the largest ever breathing the air. The contaminated air in tend to support the arch. The outside of used under either the Hudson or the East this particular test showed .075 per cent, car- these segmental steel tubes is covered over rivers. The Rotherhithe tunnel, under the carbon monoxid, and 6 per cent, with a fairly thick coating of concrete. Thames River in England, was driven with bon dioxid, which proved that the per was so small as Here is where the Goethals proposal differs a shield 30 feet in diameter thru clay mixt cent, of carbon monoxid radically from former practise, and there with shells, pebbles, loam, a much firmer to be negligible. With the data thus ob- is considerable discussion now taking place material than that under the Hudson. tained, it was calculated that air supply as to the feasibility and practicability of Of course, the traffic would have to be fans with a maximum capacity of 360,000 his proposed design, which is as follows handled so that approximately half of the cubic feet of fresh air per minute, and ex- General Goethals' proposition is that the vehicles would move eastward and the haust fans having 20 per cent, more ca- tunnel be constructed of O'Rourke concrete other half westward. Once the tunnel is pacity, would be required to ventilate the blocks in segmental form. Outside of this built, however, this becomes a problem for tunnel. The total amount of horse-power tube a gravel packing is to be placed. Some the traffic engineers of that year to solve. computed for operating these fans was 750 experts seem to doubt whether such a tube According to the Goethals plan, the fresh H.P. The length of the proposed tunnel would be thoroly water-proof, and also air duct is at the top of the tunnel, and under the Hudson, from portal to portal, what would happen in case of an earth- fresh air is constantly pumped along this would be approximately 9,400 feet, with a quake or other severe concussion, as when duct by means of powerful electrically- distance of about one mile, or somewhat a powder boat or supply of explosives driven blowers and fans, while the foul air, over 5,000 feet between the bulkhead lines. might happen to blow up in the harbor, as including exhaust from the gasoline ve- As aforementioned, London has built two has occurred several times during the war, hicles, is drawn out thru ducts at the bot- vehicular tunnels under the Thames, one when the concrete tube might crack with an tom of the roadway. Besides, there are ad- 6,200 feet long, the other 6,883 feet. Public appalling loss of life. ditional ventilating and foul air ducts at interest in tunnels for New York was Detailed plans have been drawn up by either side of the tunnel, walled off from aroused about thirty years ago by Austin the New York State Bridge and Tunnel the roadways. Corbin, who proposed tubes under both the Commission, under the direction of Major To find out exactly what would happen in Hudson and East Rivers. Scientists charted General George W. Goethals and John F. a section of such a tunnel with a number the bottoms of the two rivers and reported O'Rourke, which provide for the driving of of gasoline vehicles operating their engines that tunnel construction was feasible. Per- the tunnel by the use of a shield forty-two therein, a test building, corresponding in haps it might have been undertaken at that feet in diameter—the method most usual cross-section to the proposed tunnels and time but for Mr. Corbin's death. Twenty when dealing with soft material. The ma- measuring 125 feet in length, was con- years later William G. McAdoo undertook the Penn- terial under the Hudson River is a soft structed at Newark, N. J. bight automo- this work. President Cassatt, of silt and sand overlaid by still softer ma- biles were operated in this building, which sylvania, persuaded his directors to author- terial of sewage origin, which is almost could be shut off air-tight and fresh air ize the construction of tubes under the Hud- fluid. These conditions are complicated by pumped in at the top and the exhaust son, also under Manhattan Island, extend- the presence of ledge rock which is occa- pumped out at the bottom, or vice versa. A ing under the East River to Long Island. sionally encountered. In a shield having a number of elaborate tests of various kinds The total underwater section of the tube diameter of twenty-five feet, there is a were carefully made by experts, including will be about 1 3/5 miles, and it is conser- difference in pressure between the top and Professor Gellert Allcman. of Swarthmore, vatively estimated that it will have a daily bottom of ten pounds per square foot. This Pa., and Dr. H. Jermain Creighton, of capacity of approximately 100.000 vehicles. makes it difficult to guard against blow-outs Swarthmore College. From a very elabo- Statistics compiled from data of 1917 show and other accidents caused by the difference rate and convincing analysis on the various that during that year 4,800 vehicles crost in pressure at the top and bottom of the gases present in the tube after the automo- over the five ferry lines between New York shield, tunnel experts consulted by the state biles had been operated for a period of and New Jersey in the vicinity of the pro- commissions have pointed out. forty minutes, Prof. Alleman reported that posed tunnel every day. The material thru The diameter of the shield used in driv- when all doors were closed and the ven- which the trench must be dug is soft silt ing the Hudson tunnel was 17 feet; that of tilators opened, after the engines of eight and mud. 12 ELECTRICAL EXPERIMENTER May, 1919 COMING INVENTIONS 2 By Ho GEIRMSBACS^ When the writer first conceived the idea of the lated into speech kept pace with the ad- thought recorder, he asked three prominent scien- THREE FAMOUS SCIENTISTS' VIEWS ON vancing thought of man. As the human tists regarding their views on recording thoughts THOUGHT TRANSMISSION race kept advancing at a slow pace, its electrically. The letters are reproduced herewith Altho I am clinging to ideals, my conception thinking qualities increased little by little, excerpted. It will be noted that Nikola Tesla dis- of the universe is, I fear, grossly materialistic. agrees with the writer as to thought transmission As stated in some of my published articles, I have and the senses correspondingly became more at all, but his letter nevertheless will give con- satisfied myself thoroly thru careful observation sharpened. siderable food for thought to many readers. carried on for many years that we are simply automata acting in obedience to external influences, This is especially true of the human think- Dr. Lee de Forest, inventor the audion, is of without power or initiative. The brain is not an ing machinery which perhaps has advanced not too sure about thought transmission. accumulator as commonly held in philosophy, and more rapidly than the senses. Thus we find Dr. Greenleaf Whittier Piekard, the inventor of contains no records whatever of a phonographic that certain senses retarded, the silicon and pericon detector, as well as many or photographic kind. In other words, there is no have even been stored knowledge or usually conceived, other wireless specialties, has several interesting memory as such as. for instance, sight, smell and hear- our minds are blanks. The brain has merely the ideas, and his letter Tvill certainly prove a reve- ing. life it quality to respond, becoming more and more sus- When man lived his wild was lation, particularly to those interested in radio. ceptible as the impressions are often repeated, this very necessary f.or these senses to be much resulting in memory, sharper than they are at present; hence our There is a possibility, however, which I have poor hearing, bad sight and very much studying the evolution of the human indicated years ago, that we may finally succeed in not only reading thoughts accurately, but repro- poorer smell. On the other hand, as the specie we must go back to the time ducing faithfully every mental image. It can be IN battle for existence becomes more and when man proper, as we know him, done thru the analysis of the retina, which is in- strumental in conveying impressions to the nerve more acute, is had not as yet arrived on this planet. and as moreover the battle centers and, in my opinion, is also capable of not as much physical as mental, it follows Our great biologists have irrefutable serving as an indicator of the mental processes evidence that everything in Nature works taking place within. Evidently, when an object that the mind and its thinking machinery is external form can only on a slow, laborious plan, one specie being seen, consciousness of the should naturally become more and more de- be due to the fact that those cones and rods of developed slowly into another from the the retina which are covered by the image are veloped, which, in fact, it does. We may smallest animalculae up to present man. affected differently from the rest, and it is a spec- safely say that within the next hundred ulation not too hazardous to assume that visual- When man was still in the what we may call ization is accompanied by a reflex action on the thousand years—which is only a small span animal stage, i.e., when he was not "think- retina which might be detected by suitable instru- of time in man's evolution—the human mind ments. In this way it might also be possible to ing," as that term is understood, he was will be an entirely different sort of project the reflex image on a screen, and with appara- wholly guided by instinct. His "thoughts," further refinement, resorting to the principle in- tus than it is today. Man's mental power if so they may be called, were probably on a volved in moving pictures, the continuous play of will be infinitely greater than what it is at much lower plane than thoughts of the thoughts might be rendered visible, recorded and present. Already we have indications that that the at will reproduced. average dog. The chances are Nikola Tesla. present day dog probably "thinks" much man's thoughts, or the effects therefrom, do better than prehistoric man. We also find Your article should be an interesting one, par- not necessarily have to remain within his ticularly as to the audion suggestion. The audion, that thought and language go hand in skull, but that they actually radiate from however, seems to have a certain wavelength limi- hand. Crudely speaking, prehistoric man tation, so that unless the waves to be recorded He the latter in a very imperfect manner. As lu 2 had no better language than any highly de- between about 3 X 10 cm. and 3 X 10 cm., they the human race advances, there is no doubt are not apt to be "picked up." veloped animal, such as a dog, cat or a that thought transference proper will be- A more likelv range to search would be from lo horse. 3 X 10= cm. down to 3 X 10 cm., that is, down to come an accomplished fact. It has already the harder rays, or to even shorter wave- thousands of years of evolution, Gamma been shown experimentally by Di Brazza, as Thru lengths, starting with the shorter Hertzian waves. however, instinct developed into crude Here the audion would be useless, save as a second well as Charpentier, that concentrated think- amplifier for some thought, and finally there came a time stage in the detection, i.e., as an ing will produce certain external effects, as other form of detector. when prehistoric man really began to think, Greenleaf W. Piekard. for instance, a slight fluorescence on a zinc as we know the term. That was the time sulfid screen, or a suitably excited X-ray when he began to utter his thoughts by While I have little doubt that there is such a thing in nature as transference of thought from screen. This would tend to prove that means of his voice. At first only a few one Drain to another, I am not aware that sufficient thoughts are of an electrical nature, having crude words were formulated, and probably data has ever been gathered on such a highly probably a very short wave length. As consisted of not much more than the gib- abstruse subject to permit forming any definite opinion. most electrical effects in space are depend- berish of a chimpanzee. Little by little Lee De Forest. organized thought arrived, and words, trans- (Contimted on page 84) The Thought Recorder is an Instrument Recording Thoughts Directly by Electrical Means, On a Moving Paper Tape. Our Illus- tration Shows What a Future Business Office Will Look Like When the Invention, Which as Yet Only Exists in the Imagination, Has Been Perfected. By Pushing the Button A, the Tape is Started and Stopt Automatically So That Only Thoughts That Are Wanted Are Recorded. — May, 1919 ELECTRICAL EXPERIMENTER 13 Pair J By JACQUES BOYER Paris Correspondent of the Elb rail \i. Experimi Airplane- Radio. Signaling Tanks. t lie four lower legs of which The "baby" Renault tanks now well are mounted on a revolving cupola which Paris, February, 1919. known in the United State-, played an im- makes it possible for the mast to be imme- diately revolved in direction. top Ill-, war having ended thru the con- portant role in pushing back the Huns. any The mast is 7'/- meters clusion of the armistice, the military They had not a huh- to do with the Allied of the from the ground. tm\v allows the publii victory and wen- constructed by the French The two searchlights are arranged in such Tof information concerning various nault. This well-known a manner that they can semi out two inde- il matters of the French French technician created man) different pendent light shafts, or the two shafts can Army. In this and in the following monthly models, some of which carried cannon anil lie converted into a single shaft of light. In Ittllfl I ] The "Radlo-steroo- French a Ir p I ano scope" li the latest radio generator ot In French X-ray the wind driven apparatus. By Its typo and antenna means It now be- em ployed . The comes possible to dynamo Is fitted rapidly locate bul- with a small air lets or fractures — blade which spins owing to the per- spective of vision It rapidly. The thus afforded. The antenna and weight X-ray plates are Il- are lowered from a luminated from be- on the cockpit. reel hind, while the Similar schemes physician views are In use on them thru the spe- American Air- cial coordinating In- planes. Fig. I. strument shown. Fig. 3. [ letters, we will unfold .thru the Electrical the inside of the tank we find our usual Experimenter the latest European techni- Morse telegraphers, operating a key which cal developments as they come to our atten- controls the light shafts. By means of this tion. arrangement, the ordinary Morse or Con- Particularly during the war, the censor- tinental Code can be sent out by breaking ship has been so rigid that many important up the light shaft into "dots and dashes" inventions have never been even mentioned the same as is done in the usual method of in the technical press. We shall he glad signaling with lights. Mr. Renault has in- to describe these monthly for the benefit of corporated several refinements into the Experimenter readers. search lights, one of which is an iris ob- turator whereby the volume of the light The accompanying photographs show tlie can be increased or decreased at will. latest system of radio-telegraphy installed on French Airplanes during the war. Fig. Radio-stereoscope. 1 shows what is called the "radio-telegraph dynamo" on a Farman airplane. This apparatus has been developed by All the French combat machines were the French engineer, M. Nemirovsky, the equipt with this or similar apparatus. Be- X-ray specialist of Paris. It has given tween 25 and 150 kilometers could be cov- wonderful results to the French military ered by means of this apparatus weighing physicians, and it now becomes possible to some thirty odd kilograms. For receiving locate metallic or other foreign pieces in the wireless waves the aviators of course the human body in a manner not possible used the audion. and by use of sound-proof The "Baby" Renault Tanks Played before. The ordinary X-ray photograph an Important Role in Pushing Back helmets, it was possible to receive the orders shows only the foreign body, but it is im- the Huns. Some of These Tanks clearly, notwithstanding the terrific noise Carried Cannon and Machine Guns. possible to tell how deep the penetration of the airplane motor. The small dynamo The "Tank Projecteur" Here is, and often the physician cannot tell if Shown Was Effectively Used for shown in Fig. 1 is operated by means of a a bullet is in front or in back of a certain Signaling Purposes. Fig. 2. small air propeller, and this motor works organ. In other words, he does not know entirely independent from the power plant just how deep the bullet is embodied. machine guns, while others merely carried of the airplane. As long as the airplane is Everyone who has looked thru the ordinary ammunition. One of the strangest ones in motion the propeller will turn due to stereoscope will readily understand how constructed by him is the "tank projecteur" the rush of the air, and thus even if the objects "stand out" and how they reveal (signaling tank). It is shown in the ac- engine becomes stalled, the aviator can still their exact location to the human eye. companying photograph. Fig. 2. This tank use his wireless, for the plane while vol- It is this principle which is made use of is built along the lines of the "baby" tank, planing down furnishes enough energy to by M. Nemirovsky, who has also greatly drive the small auxiliary dynamo. The simplified the radio-stereoscope technique. wireless antenna trails behind the airplane Our illustration. Fig. 3, shows the method. Two X-ray pictures thru the steel tube as seen in Fig. 1, at the The war has brought forth a great taken at one time by end of which there is a small pulley. At many surprises, many of which for mili- super-imposing two plates and afterward tary reasons having remained secret, developing the free end of the antenna wire there is a and them are placed side by side in many will continue a secret for some time weigTit of two or three kilograms (4 to an arrangement termed a "negatoscope." 6 to come. Our readers no doubt are very tends The plates are illuminated from behind by pounds) which to keep the antenna much interested in many of the war de- of more or less taut. The wire stays of the vices brought out during the war by our means an electric lamp. The physician airplane themselves form the "ground'' European Allies. We have therefore made then regulates the radio-stereoscope by arrangements for the wireless system. All aviators in with our Paris correspond- means of a thumb screw as shown, until he ent, Mr. Jacques Boyer to send us an sees the bones, and all the air were constantly in ti mch with each other parts as well. article each month on hitherto unpub- other, The foreign body then stands out in plain and in order that one airplane should lished information. The first article of not be mistaken for another one, different the series appears on this page. Editor. relief. The physician now examines the wave lengths were used for each. Not only plates carefully ami he obtains a clear men- tal picture which subsequently this, but other tricks as for instance, send- gives him an exact idea as to just how deep the foreign ing at a different intensity, was often re- but in the back we find on an inclined steel body is emplaced. If necessary during the sorted to by certain aviators in order that truss a little dynamo driven by the ma- operation, he can frequently inspect the the ground station would know from which chinery of the tank. Two "signaling pro- negatives stereoscopically in order to guide 'plane the signals emanated. jectors" are mounted at the top of a light himself should this be necessary. — 14 ELBCTRICAL EXPERIMENTER May, 1919 Locattiiinigf Emieinmy Gemini© by Flaslh amid So^amidl mi Switchboards Used for Flash or Sound Spot- ting of Enemy Artillery. Photo at Left Shows a Type B-T Sound Rang- ing Set Such as Used By the United States Army Signal Corps Dur- ing the War. Many of These Switchboards Were Successfully Used At the Front. It Is Slightly Larger Than the Smaller Model and Requires a Little More Time to Set Up, But On the Other Hand It Com- bines Many More Tele- phone Circuits. A Single Section Has Located as High as 117 Guns of Enemy Batteries In 24 Hours. The Right Hand Photo Shows a Small Portable Switchboard, Known as a Flash Ranging Set. This Sig- nal Board is Used in Conjunction With an Observation Telescope for Locating the Flash of Enemy Guns and General Activities At the Extreme Front, and is Suitable for Night or Day Service. THE accompanying photographs show tion afforded thru the observation data sub- the flash ranging corps. One of the switch- respectively twe of the war's newer mitted by two or more flash ranging ob- boards used in connection with the sound developments, which even the veterans servers. In other words, it is triangidation, ranging of enemy guns is illustrated here- of the Spanish-American War were not which mathematical quantity has been with. Hundreds of these switchboards were familiar with. For one thing, of course, raised to the n'th power by Uncle Sam's successfully used at the front during the "flash ranging" and "sound ranging," as artillery experts. progress of the war. A single section of they are called, are really two military de- The work of the "sound ranging" experts sound-ranging equipment located as high velopments which were brought about by in locating enemy guns, both large and as 117 guns of enemy batteries in 24 hours. the fact that vastly greater numbers of guns small, is somewhat different from that of {Continued on page 68) were used in the great world war than were ever even dreamed of before. 9 Let us first consider the "flash spotter." World © ILarEestt Generator The flash spotter usually takes up his lo- cation in the vicinity of front line trenches, The accompanying illustration shows one duced by induction, the primary and sec- or in a shell hole from which effec- he can of the largest water-wheel type generators ondary windings being linked magnetically tively use an observation telescope for min- ever built, and its gigantic dimensions may by means of the iron core. Transmission utely observing and locating in what direc- be judged by comparison with the figure of lines are in use at the present day with po- tion the flash of an enemy gun occurs. The the man standing beside it. This is one of tentials of 150,000 volts and higher. Photo electrical switchboard shown herewith several water-wheel generators built for the Courtesy G. E. Co. forms a part of the communication link Keokuk electric generating station of the with the artillery and general intelligence Mississippi River Power Company. This headquarters, so that the position of the mastodonic generator has 52 poles and de- enemy guns can be quickly made known, livers a current at 11,000 volts potential. and either shelled at once by counter-bat- This is a high voltage for a generator to tery fire by the artillerists, or else the lo- produce, owing to the strains on the re- cation is accurately plotted on large maps volving windings, etc. Much higher volt- for future consideration, depending upon ages are frequently used for the transmis- the activity of the enemy gun or guns at the moment. sion line, and voltages of 50,000 to 75,000 are common for such transmission, these The flash spotter, if he happens to be lo- extra high potentials being obtained by cated in a listening post or shell hole, or means of stationary transformers in the in fact in any other forward location, in- power station where the generators are lo- variably has with him his trusty portable cated. telephone connected by wire to the nearest The large field or stator frame here communicating depot, where find we one of shown forms the stationary part of the the small portable switchboards here shown. generator, and the rotatingmember which These switchboards are fitted with the is also of gigantic size and mounted on a proper regulating instruments for creating steel shaft several feet in diameter, is put the best working conditions on the various in place and lined up with high accuracy circuits, and make provision for connecting when the stator frame of the generator is and disconnecting a large number of cir- put in place and bolted to its foundation. cuits, in some cases, about 30 or 40 lines These large machines are invariably built in running out to various flash ranging obser- sections which can be bolted together after vation stations, or in other cases as many they have reached the site of their as or installa- 100 more lines. The work of the flash tion. spotter is finished for any particular case The transformer comprises a laminated when his observations, as to the angle in sheet iron core on which there are two which the flash was observed, and a similar windings or series of windings, one of or different angle measured by a co-observer which forms a low voltage primary which somewhere down the line, have reached the is connected with the generator, driven by engineers. These experts, by means of a water-wheel or other source of primary special slide rules and tables, quickly solve power; while the second set Note the Relative the of windings Size of the Man Compared distance of the enemv gun and its defi- to the form a high voltage or secondary circuit, in Huge Stator of the Largest Water- nite location geographically Wheel Type Generator Ever Built. bv the informa- which any desired potential It De- current is in- velops a Current of 11.000 Volts. ! , — May. 1919 ELECTRICAL EXPERIMENTER 15 Novel Electric Talking Sign the Icticr "K." is struck, "K" will ap- accompanying illustrations, Figs. time; it is then released by pressing a single and iii th<- and green light No. t lit- construc- key. monogram THE1, 1 and 3, show design, that a re- 3 will burn. If it does not barn, the oper- tion and method of operation of an It is of interest to note unit to strike ator knows that the "K" (ailed to appear elei tnc bulletin board, operated by a leasing device enables the "I" ratpr it with an- in the monogram and he strikes it again. typewriter, which is said to be the any one letter can and replaci the other When the operator writes a bulletin, the latest achievement in the electric si other without interfering with . riter keys dustry. T h i a write on paper new illuminated t h e usual sign called the in Elect rograph manner. This gives a complete has been ei record of every- on the Dispatch thing that ap- Building in < o- pears on the lumbus, h i O, board. The rec- and flashes the ord is used in latest n e w s checking adver- fresh from the tising. press wires, and is claimed advertising bul- It that an ordinary letins for local bulletin may be and national written in ten concerns. seconds. It It may be usually is 1 eft stated that this burning ten or I 1 1 u m i n ated seconds Sign has two mure after being sides, each side completed. This holding sixty tes the monograms, ar- amount of ad- ranged in three vertising rows. Each and monogram con- news that may flashed in an tains a clever \M3rn be The "Electrograph" Talking Sign Here Illustrated Is arrangement of evening. the Last Word in Electric Signs and Advertising De- Mr. Alton D. twenty - one vices. It Is Operated by a Typewriter Keyboard, as Upper Right View, Fig. 1, Shows. Local Adver- :er, of the lights, combina- the RD0S B, G tising Bulletins and "News", Fresh from the Wire, jV VICTORY TO Evening Dis- tions of which with Great and T Are Flashed by This System, Success M HE ALLIED patch, points out form any letter at Economical Cost. The Gigantic Sign Here Seen CRUSE that the news or numeral and Is Located in Columbus, Ohio. It Has Two Faces, Holding Sixty Monogram Letters. the a few other Each Side feature gives electrograph an characters, each s^S^S^S^S^S^S^S^S^S^Sl one measuring advertising pull not possible with two by three feet. ordinary electric signs. Latest news from The photograph Fig. 1 shows the operat- letters. Thus, if an error is made, it may bound to attract at- ing room. The typewriter method of oper- be promptly corrected. The operator can- the peace table fronts is watch for ation distinguishes this device from others not see the sign as he works and so a pilot tention, and while the crowds the advertisements. On of similar character. A standard machine board has been provided directly in front news, they read light bulbs, election night the electrograph is the center is used and contacts are made by striking of him, consisting of sixty green returns are flashed the keys just as they would be struck in corresponding to the sixty monograms on of attraction, as the other ordinary typing. An extra platen, bearing either face of the board. When a letter is more promptly than is possible by any course, increases silver plugs, over which a stylus rides, se- struck, with the platen set at any given means. This service, of the advertisers and lects the monograms automatically as the position, the letter appears in the corre- the value of the sign to writing proceeds, thus throwing the letters sponding monogram and automatically gets more results from them than they hanging in front of in their proper places on the sign. The let- lights the corresponding green light. could get from a sign at less cost. ters remain in place until the bulletin is For illustration, it will be seen that if the their places of business and completed and may be held any length of platen is set with the stylus on Xo. 3 plug By Frank C. Perkins. ieviimg* tlhe Car CiMiisIta By Sidney Geipinvslback. HAVE you ever seen a Subway crowd of the car. Our well trained eye reads these can mean only one thing : somebody wants being herded into a car? Of course signs, like an Indian would read footprints to get off that train! And if somebody off, half other bodies you have, if you are living in "little on the warpath : These spasmodic move- wants to get a dozen old Xew York." If not, thank the Lord ments, this pushing, twitching and thrusting want to get on, and usually do, too. and turn to the next Acting on this well page. You are not established principle interested ! Xot at we push and get all ! And then again pushed toward the you may get a notion open car door. A to visit that "Burgh" melodious voice one day; well, read from the end of the on, it may interest car sings out : "Let you after all 'em get off ! Let 'em Let us go back to get off !" And be- that Subway crowd - hind you a gentle- on a rainy Monday man wearing t h e morning between 8 '^feSLw^rf snug uniform of a and 9 A. M. and let Sub w a y gladiator The Cure for the "Subway Crush".—There us try to board a car at Times Square. pushes on: "Step lively!" Are Three Doors on Each Subway Car: Two There our train stops, packed brimful with And right here it is where Kipling is on Each End and One, About the Same Size its rain-smelling, sneezing and coughing wrong about that east and west business as the Front and End Door Combined, In !" cargo. You think there is not room for as the Center. Let the Outgoing Passengers "who never shall meet Take it from an much as another umbrella in the car you Use the End Doors Only, and the Incoming old Subway traveler: they do meet! They have selected. But behold the convulsory Travelers the Center Doors Only, as the not only meet ! They clash and they col- jerking and pushing going on in the middle Diagram Indicates. (Continucd on page 56) ! 16 ELECTRICAL EXPERIMENTER May, 1919 pagg5BGTO^:g^;i!j.''iu.'.^^ "Jia^nr;; mz&mii}iA!iJii>i!i'.vJi m'.m >ift»» ^Mm&mmmwjrzmJi'W vMmm %MMMMg!i iij lwwmntlom.§ By Nikola Tesla IV. The Discovery of the Tesla Coll and 1 ransiorm-eir MbwriMiM^r)Sflftwi^hw&fflbwii5ifir7»i[a!^ ^OR a while I gave myself up entirely to the intense en- I never can forget the deep impression that magic city produced joyment of picturing machines and devising new forms. on my mind. For several days after my arrival I roamed thru the It was a mental state of happiness about as complete as I streets in utter bewilderment of the new spectacle. The attractions have ever known in life. Ideas came in an uninterrupted were many and irresistible, but, alas, the income was spent as soon stream and the only difficulty I had was to hold them fast. as received. When Mr. Puskas asked me how I was getting along The pieces of apparatus I conceived were to me absolutely real and in the new sphere, I described the situation accurately in the state- tangible in every detail, even to the minutest marks and signs of ment that "the last twenty-nine days of the month are the tough- wear. I delighted in imagining the motors constantly running, for est!" 1 led a rather strenuous life in what would now be termed in this way they presented to the mind's eye a more fascinating "Rooseveltian fashion." Every morning, regardless of weather, I sight. When natural inclination develops into a passionate desire, would go from the Boulevard St. Marcel, where I resided, to a one advances towards his goal in seven-league boots. In less than bathing house on the Seine, plunge into the water, loop the circuit two months I evolved virtually all the types of motors and modifi- twenty-seven times and then walk an hour to reach Ivry, where cations of the system which are now identified with my name. It the Company's factory was located. There I would have a wood- was, perhaps, providential that the necessities of existence com- chopper's breakfast at half-past seven o'clock and then eagerly manded a temporary halt to this consuming activity of the mind. await the lunch hour, in the meanwhile cracking hard nuts for the I came to Budapest prompted by a premature report concerning the Manager of the Works, Mr. Charles Batchellor, who was an in- telephone enterprise and, timate friend and assist- as irony of fate willed it, ant of Edison. Here I I had to accept a posi- was thrown in contact tion as draftsman in the with a few Americans Central Telegraph Office who fairly fell in love of the Hungarian Gov- with me because of my ernment at a salary proficiency in—billiards. which I deem it my priv- To these men I explained ilege not to disclose my invention and one of Fortunately, I soon won them, Mr. D. Cunning- the interest of the In- ham, Foreman of the spector-in-Chief and was Mechanical Department, thereafter employed on offered to form a stock calculations, designs and company. The proposal estimates in connection seemed to me comical in with new installations, the extreme. I did not until the Telephone Ex- have the faintest concep- change was started, tion of what that meant when I took charge of except that it was an the same. The knowl- American way of doing edge and practical expe- things. Nothing came of rience I gained in the it, however, and during course of this work was the next few months I most valuable and the had to travel from one employment gave me to another place in ample opportunities for France and Germany to the exercise of my in- cure the ills of the pow- ventive faculties. I made er plants. On my return several improvements in to Paris I submitted to the Central Station ap- one of the administra- paratus and perfected a tors of the Company, telephone repeater or Mr. Rati, a plan for im- amplifier which was proving their dynamos never patented or public- and was given an oppor- ly described but would tunity. My success was be creditable to me even complete and the de- today. In recognition of lighted directors ac- my efficient assistance corded me the privilege the organizer of the un- of developing automatic dertaking, Mr. Puskas, regulators which were upon disposing of his much desired. Shortly business in Budapest, of- after there was some Fig. 1 fered me a position in —Tesla Oscillation Transformer (Tesla Coil) Presented by Lord Kelvin trouble with the lighting Before the British Association in August. 1897. This Small and Compact Instru- Paris which I gladly ac- ment, Only 8 Inches High, Developed Two Square Feet of Streamers With Twenty- plant which has been in- Five Watts From the 110 Volt D. C. Supply Circuit. The Instrument Contains a cepted. stalled at the new rail- Tesla Primary and Secondary, Condenser, and a Circuit Controller. Copyright. 1919. by E. P. Co. All rights reserved Mr. Tcsla's articles started in our February issue May, 1919 ELECTRICAL EXPERIMENTER 17 iburg, AJ • i"ii thai ( u than ur> msume on tli' a wall thai pn e of the unforgettable I ircuil right in the old incidents t" which h rred. Mj I 'turn was blown out thru | of th' I ; eror William I The Germai ed to take to Pal ek support i was the plant and the French Companj was anxious to do but my work and negotiate know ledge of thi < ierman Ian to all ! at at tini' ted situation seemed hopeless. with the difficult task of ut matters German "Efficiency". and earl) in 1883 I went to an idea of Strassburg on that mission. man thoroness and "ef- The First Induction Motor Is ficiency," I may mention Built. her funny cxperi- Some of the incidents in An incandescent lamp that city have left an indel- of 16 c.p. was to be pli ible record on m in a hallway and upon se- By a curious coincide lecting the proper location I number of men who subse- red the monteur to run quently achieved fame, lived the wires. After working there about that time. In for a while he concluded later life I used to say, that the engineer had to be "There were bacteria of consulted and this was done. greatness in that old town. The latter made several ob- Others caught the disease jections but ultimately but I escaped !" The prac- agreed that the lamp should tical work, correspondence. be placed two inches from and conferences with offi- the spot I had assigned, cials kept me preoccupied whereupon the work pro- day and night, but as soon ceeded. Then the engineer as I was able to manage I became worried and told me undertook the construction that Inspector Averdeck of a simple motor in a me- should be notified. That im- chanical shop opposite the portant person called, inves- railroad station, having tigated, debated, and decided brought with me from that the lamp should be Paris some material for that shifted back two inches, purpose. The consumma- which was the place I had tion of the experiment was, marked. It was not long, however, delayed until the however, before Averdeck summer of that year when got cold feet himself and I finally had the satisfaction advised me that he had in- of seeing rotation effected formed Ober-Inspcctor Hi- by alternating currents of eronimus of the matter and different phase, and without that I should await his de- Fig. 2—This Illustrates Tests With Spark Discharges From a Ball of Forty sliding contacts or commu- Centimeters Radius in Tesla's Wireless Plant Erected at Colorado Springs cision. It was several days in 1899. The Bnll Is Connected to the Free End of a Grounded Resonant tator, as I had conceived a before the Ober-Inspector Circuit Seventeen Meters in Diameter. The Disruptive Potential of a Ball, year before. It was an ex- Is. According to Tesla, in Volts Approximately V — 75,400 r (r Being in was able to free himself of Centimeters), That Is, In This Case 75.400 x 40 ~ 3.016,000 Volts. The at quisite pleasure but not to Gigantic Tesla Coil Which Produced These Bolts of Thor Was Capable of other pressing duties but High Tension Secondary. The compare with the delirium Furnishing a Current of 1,100 Amperes in the last he arrived and a two- Primary Coil Had a Diameter of 51 Feet! This Tesla Coil Produced Dis- of joy following the charges Which Were the Nearest Approach to Lightning Ever Made by Man. ^^ hour debate followed, first revelation. — when he decided to Among my new- move the lamp two THE proverbial trials and tribulations known to every inventor were not spared Tesla, friends was the for- the world's greatest inventor of all times. In this article we see him, arrived at inches farther. My mer Mayor of the young manhood, struggling along in a cold world. Already his fame has spread far and hopes that this was wide and his genius is recognized. Hut concertina genius and fame into dollars and city, Mr. Bauzin, the final act were shat- cents is quite a different matter, and the world is full of unapprecialive and unscrupu- whom I had already tered when the Ober- lous nipn. Tesla, the idealist, cared little for money and thus was promptly taken - in a measure a c advantage of. Hut let Tesla himself tell you in his own inimitable style. It is a wonder- Inspector returned quaintcd with this and ful story. and said to me : "Re- In this month's installment Tesla also tells us hon he made one of his most important other inventions of gierungsrath Funke is as well as sensational discoveries —the Tesla Coil. Ten inventions have caused such a mine and whose sup- so particular that I sensation as this one which culminated in the only man-made lightning ever produced. port I endeavored to The Tesla coil has so many uses and has been built in so many styles that it would take would not dare to give enlist. He was sin- a catalog to list them all. From the spectacular high frequency stunts on the stage down an order for placing the "violet" ray in your home; all are Tesla coils in one or another. cerely devoted to me to machine form this lamp without his Wireless without the Tesla Coil would not he possible today. Without an oscilla- and put my project explicit approval." tion transformer, snarl; gap and condenser which is a Tesla Coil—the sending station before several would be crippled. Accordingly arrange- wealthy persons but, Hut it is for industrial purposes where the Tesla Coil will shine brightest in the ments for a visit from to my mortification, future. The production of Ozone, the extraction of \itrogen from the air in huge that great man were quantities — all are children S fertile brain. His coil is the key to them all. found no response. of Tesla' made. We started EDITOR. He wanted to help me cleaning up and pol- ^^^-^^™^^~»™^™^^^^™»«^^^ ^^^^^^^™^^^™^—™"^^™^^^"^™" in every possible way ^ ishine early in the and the approach of the first of July, 1919, happens to remind me morning. Everybody brushed up, T put on my gloves and when of a form of "assistance" I received from that charming man. Funke came v itli his retinue he was ceremoniously received. After which was not financial hut none the le^s appreciated. In 1870. two hours' deliberation he suddenly excla'roed: "I must be going," when the Germans invaded the country. Mr. Bauzin had buried a and pointing to a place on the ceiling, he ordered me good sized allotment of St. Estephe of 1801 and he came to the (Continued on page 64) : 18 ELECTRICAL EXPERIMENTER May, 1919 to Sfinow aeronautical exposition which of the stations at the Madison Square Gar- wonderful indeed, to stand in the crowd be- THEwas held jointly in Madison Square den or 69th Regiment Armory could be es- fore the radio exhibit, and hear this con- Garden and the 69th Regiment Arm- tablisht with the flying 'planes or dirigibles, versation flitting back and forth between ory. New York City, March 1st to and in turn wireless telephonic speech was the operator in front of you and a second 15th, was the most successful aero transmitted from the aircraft to the respec- operator flying thru the air at a speed of show and exposition ever held in the United tive land stations. The effect on the public SO to 100 miles an hour. States. Many remarkable exhibits were was startling, as while most of them had One day a captive propaganda balloon shown, including large bombing 'planes, undoubtedly read of the wireless telephone, broke from its moorings over the Sixty- small high-speed pleasure and scouting they did not have the slightest idea as to ninth Regiment Armory and shot into the 'planes, besides a gigantic naval sea plane. what the apparatus used for the purpose clouds, spilling leaflets, its anchorage dang- Below:— Photo of One of Uncle Top View:— New British Super- Sam's New Coastal Airships. Zeppelin. This Photograph. Pub- Showing the Main Cabin and lication of Which Is Now Per- Engine of the ,1 C-7". One of mitted. Shows the Construction These Modern Dirigibles Was of the Monster British Airships. Exhibited at the New York Aero The Picture Gives an Excellent Show and Attracted Much At- Idea of the Construction and tention. The "Ship" Exhibited Shows the Separate Gasbags ior Had Done Seventeen Months' Ballonets) Which Are. However, Patrol Service Along the Atlan. Covered Over When In Flight. tic Coast: the Dirigible Was Lower Right View:—The Aft Filled With the Wonderful New Engine House, Showing Revers- Balloon Gas— Helium —Which is ible Propeller System for Lifting. Non-inflammable. —Photos by Central News Photo Service. N. Y. and a powerful Caproni tri-plane. A cap- looked like, or how it worked, and many of ling. Up to approximately 3,000 feet it tured German 'plane of the Albatross type them had a twisted notion that it had some- sailed, where it exploded in a burst of was also exhibited. There were also shown thing to do with telegraphy somehow or brown smoke, falling upon a roof in the a number of gas type, or lighter-than-air other. However, Uncle Sam's radio ex- neighborhood of Fifth Avenue. Came the aircraft, such as solo balloons, blimps, a perts, as soon as they got the sets up and wireless comment from an airplane aloft naval dirigible which had seen seventeen working, soon showed the visitors how the "Did you see that? It burst about a months' service on coast patrol work, etc. wireless telephone worked. The roof oper- thousand feet under us—ought to make good The "gas bags" were filled with the new ator, who is stationed at that point so that stuff for the reporters. By the way, are any- balloon gas—Helium. The individual ex- he could readily observe the approach of down there?" hibits included many interesting auxiliary aircraft, would start calling the airplane or ' Yes," broke in a newspaper man stand- appurtenances in the flying world, such as dirigible as soon as it came to view, some- ing near the land wireless set, "and will you rapid-fire photographic cameras, aircraft what in this fashion: "Hello airplane! spell your observer's name for the re- machine guns, measuring instruments for Hello airplane! Hello airplane!" After a porters?" indicating the velocity of the 'plane thru the few moments' pause, and when the oper- "Yes—it's Sergeant S-a-u-v-e-g-e-a-u. He air, et cetera, and a host of other new and ator had manipulated the tuning of the ap- had a date to come to New York this after- highly novel devices. paratus to the right point and gotten his noon, and altho he's come he can't fill his Radio-telephony was demonstrated by the Audion detector and amplifiers adjusted date very well, unless he comes down and Army Radio Corps of the Air Division in a to the proper strength, the voice of the pilot lands on the crankshaft. Anything else?" very popular and interesting way. During on the airplane, hovering in the air several "No, thanks," said the reporter as he the course of the exposition, various types hundred feet above the aero show, could hung up on the first interview by wireless of aircraft flew over the city, equipt with be heard— calling, thru a large Audion am- telephony yet recorded. wireless telephone and telegraph installa- plifier "Hello land station ! I get you all The radio apparatus exhibited, including tions, so that communication from either right now, land station !" It was really very that in the exhibit of the United States May. 1919 ELECTRICAL EXPERIMENTER 19 aviator's and in the : Navy, was that of the vacuum bulb or \u eign bombing planes, including the Hand- the breast, win- fitted with a wind-driven which there i~ a metal plate containing dion type. The range of the wireli Page, mall holes about si lie. phone airplane apparatus for transmittin generator, 'I Ins small dynamo is the one side of the waves of the airplane operator and receiving speech signal a usually mounted just to t . is secured impil this plate, and course, with the size of the transmit kpit, and rigidly airplane speeds thru readil) pass thru th n it, the length of the aerials used on the air- to the wing As the small thus vibrat diafram of the micro- plane and several other factors. It is inter- the air. the propeller on the dynamo current phone, while the violent swirling noises set to note at llus point that only recent- is rapidly spun, and the necessary up by tl ly Secretary of the it without Navy Daniels cat g tiie diafram (hi a wireless telephone thus | convei March l lere are some the 11th with an airplane of ding electrical flying over the 1' and features at a distance of o ther which appealed I 150 miles. In this two- visitor of th( way wireless telephone conversation with the in lookinj Secretary of the Navy, the airplanes of I signs, • and who was located at Washington, he used small. of the 'plants one found red his ordinary desk tele- phone, which was con- and green signal lights, placed re- nected up to the wire- winch were spectively on the ex- less transmitting set in another building. A treme outer ends of the Another recent report states lower wing. that radio-telegraphic novelty was the electric communication from searchlight of small the earth to plane has been size, mounted over carried on over a dis- kpit so as to be tance of 200 miles. The Fastest Airplane Exhibited At the Aero Show In New York—Th e "Christmas Bullet" rapidly manipulated by Used "Taxiplane" The form of antenna — Rated Speed 200 Miles Per Hour. Test Showed 185 M.P.H. To Be as t| le pil,,t or his assist- to Deliver Dispatches to Vessels One Day Out At Sea. used on aircraft dur- ant, for the purpose of ing the war has been m a king landings at invariably that employing a quick-acting thus produced for operating the radio tele- night or helping to locate the enemy in a exhibits were reel, on which the phosfor bronze stranded phone or telegraph instruments. Whenever night attack. Many interesting antenna cable was wound upon or released an airplane or dirigible was in radio tele- on hand of the various magneto ignition from, according to the desires of the pilot. phonic communication with the station at systems. A beautiful model was shown of a However, in the newer aerial systems as ap- the show, the most frequent question heard spark phase-angle indicator, which roused plied to the airplane, not one, but two aerials among the audience was: "Why is it that great interest among the spectators, as the are utilized, and no reels are employed. the terrific noise of the airplane engine is sparks staggered around the edge of a black disc, which Each wire is about 100 feet long, with a two- not heard above the comparatively weak rapidly revolving two-foot pound lead weight at the end, and flies out voice of the pilot?" The explanation is was covered over with sheet glass. Of from either extreme of the wings. These simple when you know how it is done. The course, there were electric lights in the wires, contrary to popular conception, are explanation for the non-transmission of the aviators' quarters, or cockpit, besides many allied features said not to interfere with the maneuvering airplane engine exhaust noises is as fi illows : other electrical and of great systems between of the plane at all. One of the officers at the Many weary weeks were spent in special re- interest, such as signaling radio exhibit explained that the 'planes can search on this particular problem by ex- the pilot and the observer, provision for rise and land with these wires outstretched perts of the concerns who developed the supplying current to the electrically-heated without any trouble. One of the wires radio telephone during the war, under great aviator's clothes, which the aviators always forms the aerial, while the other forms a pressure, but thanks to their keen percep- wear on long distance trips, or in night fly- success- ing when it is particularly cold. counterpoise ground capacity. The tuning t ion of the principles involved in and detecting apparatus are connected be- fully telephoning by radio from a moving Other exhibits included luminous radium tween them in the cockpit. vehicle in the air, in proximity to a terrific dial measuring instruments and gages, elec- In looking over the wireless equipment on noise such as produced by the airplane, tro-pneumatic and other forms of aerial the various 'planes, one was struck by the these engineers had the forethought to raphic apparatus, some of which wide-spread adoption of the wind-driven finally devise a special sound detecting in- operated at very high speed, as can be read- wireless dynamo, and even the gigantic for- strument or microphone, which is strapt to (Continued on page 60) Wireless Telephone Set, Transmitting and Receiving. Used on Airplanes. Airplane Radio at the 'Aero Show.' Left:—A Short Range wire- Center:—A Radio Direction Finder, Used for Locating Direction of Transmitting Stations. Right:—The Airplane "Land Station In New less Telephone Set, Transmitting and Receiving. One of the Many Exhibitions of the Special Feature at the Aero Show Held w communication City. The Management of the Show Arranged for Demonstrations and Exhibitions of the Many Developments of Aerial Recently Adopted by the U. S. Government. 20 ELECTRICAL EXPERIMENTER May, 1919 Momisfter Escalator for New York Suilbway HE New York subway system has in- accompanying illustration shows a sectional in the morning when the traffic thins down, corporated in its various ramifications view of this subway innovation, which until it is about half uptown and half down- T of some the most novel engineering promises to make this station one of the town, then two parallel escalators can be upward and the other two downward. If the traffic is quite light, it will be up to the sta- tion master to cut out two of the escalators and block them off, running one of the re- maining pair upward and the other down- ward. As the crowd slowly changes and be- comes a strong uptown- bound traffic, toward the latter part of the afternoon, then all of the escalators will be run downward. The reason for install- ing the escalators at this station was because of the fact that the 7th Avenue Subway, which dives under the Inter- boro Subway, running under Broadway at this point, has to pass under the latter Subway, an.) as it is located about three levels under- ground, this renders present climbing to the street up existing stair- ways a very tedious and laborious exertion, which is almost as bad as climbing the steps of the Washington Monu- An Innovation in Escalators is to be Tried Out at the Park Place Station of the Seventh Avenue Subway In ment. Of course, the New York City. Four Escalators Will be Available. Any Or All of Which May be Operated Either Or Up Down, present staircases will Depending Upon the Direction of Traffic, Which Is Mostly Eastward in the Morning and Westward at Night. remain in place, as under the condition features possest by any similar transporta- highest speed stations of its kind in the where north-bound traffic might necessitate tion system in the world. Moving plat- world. operating all of the escalators downward. forms have been suggested and tried in The four escalators to be finally installed then passengers arriving on southbound various New York transportation systems, will be reversible, and several ways of oper- trains would have to gain access up these and stairways moving or escalators are not ating these electric motor-driven moving stairways to the street. It would probably unknown to the metropolis' subway and ele- stairways will be available. In the morning be more expedient to operate three of the vated railroad traveling public by any when this downtown station of the great escalators downward and one upwards, a means. But one of the interesting most and metropolis is flooded with office-bound pas- problem which the traffic engineers will have highest lift escalators is now being built at sengers, then if necessary all four of the to determine by careful check over a con- the Place and Park Broadway station of the escalators may run upward to carry the siderable period of time, after the escala- 7th Avenue Subway, New York City. The traffic to the street. After about 10 o'clock tors have been in operation for a while. lURl^taiiniE ©f AM Min Lightning photos are more or less com- mon, and a great number of them have been publisht in the various issues of this Journal from time to time, but one of the most astonishing lightning pictures ever recorded by the camera, is that shown in the accompanying view, which incorporates every form of lightning, such as bead, forked, chain and ribbon, so-called heat or flash, and ball lightning. This picture is extremely interesting to all photographers, who have attempted to obtain good photos of lightning discharges. It is quite a trick to photograph lightning in j ust the way you would like to have it appear on a finished picture. In some cases, and as is the usual practise, excellent lightning pictures are obtained by waiting for a dark period just after a flash, and then opening the camera shutter, which has previously been set for a time exposure. As soon as the next flash of lightning oc- curs, the shutter is at once closed, and the plate then developed. This sounds simple, but as Shakespeare said, "There is many a slip twixt the cup and the lip," and one humorous instance comes to mind of an am- bitious lightning photographer, who sud- In this Remarkable Photo Lightning of Many Kinds—Chain, Bead, (Continued on page 56) Forked and Ribbon Varieties—Are Shown. A Photo Hard to Beat. — May, 1919 ELECTRICAL EXPERIMENTER 21 BrMslh Sufllbinnisirme Detector 1 ex- war. Wires lead to various stations on the ship, at which list arc posted. By thi steady watch is kept and theap- l craft aided. ( >ne of the pi a model submarine in an experimental tank, showing the hydrophone in tin tank, while the man with the receivers the Bounds from the propeller which warn of the appi oaching submarine. Practically all of the British ships were equipt with the de- and it is acknowli that many ships were saved by means of the instrument, which The Views Herewith the "Hydrophone" Or Show is somewhat like a dictagraph, Super-Sensitive Sound Detector Used by the British Navy In Clearing the Seas of U-Boats. The Left i.e., a super-sensitive telephone Hand Photo Shows the Device Being Demonstrated transmitter connected with a In a Museum, Where a Model "Sub" Lies In a Tank low resistance telephone re of Water. View at Right Shows a Close-Up of Microphone. ceiver. The sound detecting microphone is placed in a sub- merged part of the hull. Elecforic VaoMim «=Vnira taoso & Marvel One of the most wonderful musical in- rich and sonorous. Furthermore, one by Electri- struments ever perfected is the electrically The one, there has been added to the Violano- played violin-virtuoso shown herewith. c a I I y Played Violin is Truly Virtuoso various devices for producing not Musicians said it could never be done a Wonder of only the staccato, but the arpeggio, Modern Sci- but it has been accomplisht at last, with a tamento, pizzicato, shake, trill and all other ence — It Was range of action almost, if not, indeed, actu- Long Predict- musical variants peculiar to violin playing. ally, miraculous. ed That Such Sixty "fingers" perform the action. As The control of both speed and pressure a Device the contact cylinder carrying the paper ( Could Not Be Fed of the bows of the self playing violin is by a secondary cylinder,) Built. But It revolves, and the said to be perfect. Regardless of how fast Has — and perforations in the music roll pass given or slow the tempo the proper ratio of pres- Sixty Magnet- points, contact is made with one or more ically, Oper- sure is consistently maintained. This is ac- of brushes ated Fingers the and an electric current tl complished by means of a small electric Do the Work to finger magnets resting over the finger motor possessing a speed of from 200 to — and Play board. Each of these magnets attracts an (and any intermediate revolu- Better Than 6,000 rate) Most Human armature connected with a finger operating tions per minute, and so constructed that Violin- rod acting upon the violin strings. The the amount of pressure applied to the bows ists. Four same current also acts simultaneously on magnets Op- is automatically and accurately regulated erate the the bow action magnets. Another magnet by the speed. Thus even the softest notes Bows. produces the "staccato" while the tremolo are clear and sweet, while the loud are (Continued on fa 'uslhi a B^atttonn — Geft a ¥h The Federal Agricultural Agent up in resources and needs of every farm. An ing on an electric switch. The survey has Litchfield, Conn., being frequently called electric sorting machine was installed in the been invaluable by helping. Connecticut to upon to help farmers find things they need- State Library, and any fact disclosed by mobilize her agricultural forces for peace ed and having no definite means of knowing the survey can be made available by throw- needs. where they were to be bad except iur heard on his rounds, conceived the idea of an agricultural survey. Now, if you want to locate a supply of seed corn or oats, a grain binder, a pure-bred bull, or some young pigs, in any community in live coun- ties in that State, all you have to do is to walk into the office of the State Librarian at Hartford, run a scries of cards thru an electric sorting machine, and, Presto ! you have the information. It may sound a little like the story of Aladdin's lamp, but it is only big business applied to farm affairs under war stress. &? The Council of Defense took up this plan and offered to back the farm bureaus to the limit in every county in the State. Five of the eight counties began surveys early in March, 1918. Forty questions, under the headings of area, crops harvested in 1917, crops planted to be harvested in 1918, live stock on hand, machinery on hand, and em- ployes, were included in the survey, and a corps of volunteer farmer census enumera- tors got busy. When the survey was com- Push a Button pleted the farm bureaus had a stack of cards —Get a Pig! Sounds Incredulous. Does It Not? Yet Up in Connecticut They Have Such an Electric System in Operation. Don't Exactly Pig Or containing minute You Get the Cow by information as to the Pushing the Button, But You Do Obtain Data as to Where You Can Buy Them. 21 ELECTRICAL EXPERIMENTER May, 1919 tmltttiiinu It Oveir ©mi immediate ancestor of the Trfcks aiad Odd Slauafts exploding in the confined lane of a trench THE"Mills" hand grenade was the "jam will kill three and wound six soldiers, it is tin." This was an awkward and ©fWarfaire ftlhaft P*s2&° fairly safe to assume that this simple trick cost the Germans at least unreliable species of bomb, shaped sled tfcS&e M^aia five thousand like a canned soup receptable, with a men in killed and wounded! From that it official practise the six- or eight-inch projecting fuse intended Over a sixty-kilometer front in the Ver- day forward was in lines let severely to burn four seconds. Sometimes it ful- dun sector the bombers were assembled and German to French bombs filled expectations exactly, but more often coached in the use of this new weapon. alone. the fuse was off temperamental. It went Simultaneously at seven in the evening , Another point at which Allied wits bested before the time was up, or sputtered long "parties" started out for the German wire. German scheming was at forecasting re- enough, after dropping in the Get man Stopping here, each of the four hundred treats by the enemy. To civilians, well- trench, to allow one of the enemy to pick bombers participating delivered himself of posted with data on the occasional ex- it up and toss it back. Because, early in the four regular "jam tin" grenades and four ploits of airplane observers, this does not fall of 1915 when this crude weapon flour- of the "imitations" before scurrying back. sound sensational in the least, but doubt- ished, bombs of any kind were so scarce Fritz noted one striking feature of the less to the Huns themselves the manner in that the soldiers often made their own, few engagement. Many of the Allied missiles which the Allied forces knew of the last opportunities for dosing the enemy with his landed "dud"; this probably was due to the retreat in the Soissons-Reims sector in time pills own were overlooked. extraordinary inefficiency of the French to take full advantage of it seemed little The last day upon which Fritz monkeyed ordnance department, concerning which the less than miraculous. No matter what air- . with "fizzers" from the Allied trenches German privates had been told so much. men may say about the photographs they with any degree of self-confidence was All along the line German defenders picked took, or the observations made by telescope November 12th, 1915. That occasion taught up the imitation duds and lighted their from a 'plane, this latter scheme could only him that even a "dud" jam tin has its lively fuses, intending to bomb the bombers with tell of a retreat actually under way—too moments. French ammunition. late for much action by the Allies. On the For several weeks preceding the date The havoc that resulted was appalling! other hand, the method described here not mentioned a French ordnance engineer had Each grenade, of course, exploded the in- only would tell for certain, two weeks in been experimenting with what he termed stant it was lighted. Because a raid was in advance of the first troop or supply train "instantaneous fuse." This was made up, progress, anyway, each individual accident movement, but would mark off the exact wound in waxed thread, just like the ordi- received no attention at the moment. If line to be abandoned,^ and tell the depth to nary fuse used in jam tins. The essential Fritz saw Heiney go up in smoke while which the Germans intended to relinquish and important difference between the two handling a French bomb, he thought simply their hold! This was done sim- ply by listening in on eta**, the unintelligible gib- ""° t^*"' berish of German trench wireless with Allied instruments. ' ' ii inili>mi|«ii Ordinarily, of course, mmm three-fourths of the signaling done in the front trenches is done I I III l.,... I J BM i He Thought He De- tected Something That Sounded Just a Little Like a Message! He Wound the Phono- graph and Turned Its Speed Indicator Down So That the Record Revolved Only a Few Times a Minute. Then He Applied the Needle Again. Aha! There Was Something There! lllllllllllllllllllllllllllll by means of tele- phone, orders being sent thru one central station by wire to all parts of the sector. Towards the end of the war, however, the Germans began to run out of wire and tele- phone instruments. varieties lay in the fact that while straight that Heiney had been too careless—tough They could not replace them because of a fuse fizzed off at the rate of one and one- luck for Heiney, but he would never get lack of the materials. Therefore they be- half indies a second, the instantaneous caught that way. A second later another gan to plan on saving every instrument and variety burned twenty-six feet a second! trick bomb would send him to join his Hun foot of wire when a retreat was to be made. Without giving the fact much publicity, Comrade. They took out the stations gradual!}-, and as several thousand jam tins identical in ap- For several minutes after the bombers they removed them they set up trench wire- pearance with the stock variety were made reached their sheltered trench the explo- less instead. The Allies, after finding out up. In every way but one these were the sions continued across No Man's Land. It this plan, simply watched the appearance of same; the six-inch fuse was instantaneous, was estimated at the time that a full thou- wireless sets where 'phone stations had been ; and was made with the end charred trifle, a sand of the grenades exploded in the hands when the wireless began to predominate it to look as if the bomb had been lighted of German soldiers before anyone found was certain that ten days or two weeks would and had gone "dud" after being thrown. out the secret. Since the average bomb {Continued on page 77) May. 1919 ELECTRICAL EXPERIMENTER 23 Cold ILLa'Ihil By ROG rSK, M. A. OLD light is one of the wonders of dioxid. The heat which this light produces was still one great drawback. Scienti-tj the modern age. Light without is almost negligible. said that as the electron revolved about its heat leema like a contradiction, Cold light is a term used to indicate lu- axis in the molecule it produced light waves c nevertheless it is a scientific fact. minous radiation without heat radiation, just like a paddle wheel in a bod) of water. Since the discovery of the electrical and that means maximum efficiency, i.e., But as all molecules of all substances con- a colder and a colder source. The old fashioned kerosene lamp wastes 36.4 cal- ories of heat per second for every candle- lov.er of light produced. The gas mantle Moo, wastes 11, and the tungsten lamp but from 1. to 2. calories / Htctron- ~wT > / Considering electric lights only, the heat • ^\V / loss in tungsten lamps has been reduced by \ Uucleus 1 s the introduction of gases such as nitrogen into the bulb, but arc lights have made a W gieater development. The invention of the enclosed arc reduced the heat loss without Fig l reducing the illumination. Then the inven- tion of the flaming arc increased the illu- El mination without increasing the tempera- ture of the arc. The latter is the most in- Diagram Illustrating the Old Theory of Light teresting development because part of the The New Theory of Light and Heat Waves, Produced by Electricity. In This Explana- Which Says that Light is Produced Inter- light from the flaming arc is cold light, tion the Electron is Considered as Continu- mittently. Here Light is Produced by the ously Producing Light Waves by Its Rota- from the chemicals in the flame which are Electron Jumping from One Orbit to Another, tion. The Newer Theory of Light and Heat ionized by the electric current. The cold as the Circular Orbital Paths Indicate. Waves Is Shown at Fig. 2. light from these ions plus the light from tain electrons which are constantly in mo- the incandescent carbons makes the flam- tion, then all substances should give off nature of light, the possibility of trans- ing arc nearly three hundred per cent more light all the time. This was ridiculous, as forming electricity directly into light, with- efficient than the ordinary' incandescent everything in the world and the whole out the production of heat, has been a lamp. universe would be of a dazzling brightness tempting goal. For centuries, scientists The first flaming arc appeared in 1900, like the sun. dreamed of solving the mystery of the fire- known as the Bremer arc, and using car- The discoveries of today are changing fly and the Aurora Borcalis, but dreamed bons impregnated with several chemical this idea completely. One of the world's in vain. They saw light without heat pro- salts. Later Steinmetz and Whitney used greatest physicists, Planck, says electrons duced in Nature, but could not produce the rare metals titanium and chromium in cannot give off light waves continuously, it themselves. their arcs and produced a still more effi- but emit definite quantities at intervals. Today the discovery that light may be cient light. About the same time the mer- This theory' he calls the quanta theory, and produced without heat, by means of elec- cury vapor light was invented, which gave another physicist, Bohr, says the time the trical ionization, seems to be the key to a brilliant bluish white light from the mer- light is given off is when the motion of the the situation, and we can only wonder cury ions in the arc. Later still is the dis- electron is suddenly changed from its nor- where it may lead us. At the present time covery by two scientists, Franck and Hertz, mal continuous motion, by its jumping from over 96 per cent of all the energy used in the that an electric current of only 4 volts, when one atom to another, or from one orbit fifty million incandescent lamps in the past thru cold iodin vapor, produces a faint to another about the same atom. This is United States, instead of being turned into light of definite color. When the voltage a very simple theory, but it is often the light, is toasted in the form of heat! More- is raised to twelve, another color is ob- simplest theory which best explains the over the astonishing production of light tained. This is true cold light, produced facts. When trillions of trillions of elec- without heat by ionization has given us a directly from the molecules as they are trons are doing this at the same time, the new view of the relation between light and ionized by the current. How this is pos- light is to all purposes continuous. These electricity and the great problem of the sible, and how light and heat may be pro- theories have received added confirmation origin of light. duced independently of each other, will now from work done recently by Prof. Millikan It used to be thought that light could be shown. of Chicago University, who gained fame onlj be produced by incandescence, that is, What the actual source of a light wave is by his original measurements of the elec- thru heating of a solid body to white heat. has been one of the mysteries of science tron itself. Strange as it may seem, the candle and since the beginning of history. The dis- The principle of the new theory can be the kerosene lamp are really incandescent covery' by Maxwell, Hertz and others that easily explained by an illustration. If a lights. The light they give off is due to light is an electro-magnetic vibration, ball is whirled in a circle on the end of a white-hot particles of carbon liberated in caused scientists to look for the electric string, the pull on the string is steady and the combustion process. Even the light charges which produce these waves. When continuous as long as the ball whirls" with from an arc lamp is mainly due to the the electron was discovered it was thought the same speed. However, if the ball is ciater in the positive carbon being heated that the solution had been found, but there suddenly stopt or hit by something which to incandescence. makes it change its course, a jerk or a The fact that hjat is not the only factor wave will be felt in the string. Now an which effects the production of light can electron does the same thing, only the be easily seen in two ways. First, salts of jerk or wave is sent out in all directions by sodium, potassium and lithium may be the electro-magnetic field about the elec- thrown in the same flame at exactly the tron. This jerk or wave is the little quan- same temperature, but the first gives off tity which Planck calls a 'quanta". The a bright yellow light, the second a violet, familiar way in which an electron is pic- and the third a deep red. Second, light is tured as continuously producing light waves, produced by an electric spark in a partial by its rotation, is shown in Fig. 1, but this vacuum, such as a Geissler tube, with Utile is wrong according to the above theory. or no heat at all. In both of these cases What really must happen is shown in Fig. the light must be produced by the breaking 2, where the two circles represent different up of the molecules, of the solid or gas, orbits and the full line represents the path into electrically charged particles, or ions, of the electron jumping from one orbit to in a manner to be explained later. another and at the same time emitting a The idea of using cold light for illuminat- quantity of radiation or light. The way in ing purposes seems to have first occurred which electricity- or some other agency to Nikola Tesla. Very early in his career causes this disturbance of the electron is he suggested that the' effects produced in not fully understood. Geissler tubes might be utilized in that The most remarkable thing about it all way. Not until recent years, however, did is that heat and light waves may be pro- his suggestion bear fruit in the shape of How "Cold Light" May be Obtained by Ex- duced independently. A heat wave is pro- the now famous Moore vacuum tube light, hausting an Ordinary Glass Tube. When duced by the vibration of the whole mole- invented by McFarland Air is Moore, which pro- Pumped Out of a Tube in Which There cule is an or atom as shown by the big arrows duces a fine soft light from a glass tube Electric Spark Discharge, a Stage is Reached Where the Whole Tube is Filled and dotted wave line in Fig. 2. And under thirty to forty feet long, filled with carbon with a Soft Luminous glow—Cold Light. {Continued on page 73) 24 ELECTRICAL EXPERIMENTER May, 1919 .Asforoinioinniicsil Disttaimce^ 8y SSABEIL Mo ILBWHS of ike U. S. Naval Observatory immensity and grandeur of the the earth to the sun, "the astronomical unit," unslackened at two hundred miles an hour. THEscale upon which the visible universe would subtend an angle equal to one second An airplane traveling at this rate would is fashioned lies almost beyond of arc. This angle is spoken of as the circumnavigate the earth in a little over human comprehension. To visualize parallax of the star. The larger the paral- five days and would reach the moon in however, the vast extent of our own solar lax ; that is, the larger the angle that the seven weeks. A trip to the sun, system which is but a single unit in the astronomical unit or radius of the earth's would require fifty-three years. system of the stars we may have recourse orbit subtends, viewed from the star, the After traveling for fourteen and a frac- to earthly standards of measurements, such nearer the star is to us. The fact that there tion years we would pass the orbit of Venus as the mile. But when we desire to express is no known star within one parsec, or three and eighteen years later the orbit of Mer- in terms of units that can be grasped by our and twenty-six hundredths light years, of the cury. If we preferred to travel outward imagination, the distances of the stars that sun shows the immensity of the scale of the from the earth in the direction of Mars and lie far, far beyond, we find that all ordi- universe of stars. the outer planets instead of toward the sun, nary standards of measurement become Before considering the distances of the more than twenty-seven years would elapse utterly inadequate for our purpose. For stars and the extent of the sidereal system before the orbit of Mars would be crost. the measurement of celestial distances witli- of which our sun and his satellites form a An airplane journey to Jupiter would be in the solar system the unit employed is part, let us undertake to express the dis- a matter of more than two hundred years, either the familiar mile or kilometer or the tance of the sun, moon and planets from to Saturn four hundred and fifty years, to "astronomical unit," which is the mean dis- the earth and the extent of the solar sys- Uranus nearly one thousand j'ears and to tance from the earth to the sun (ninety- tem in terms with which we are familiar. Neptune about one thousand five hundred two million nine hundred thousand miles in The nearest to the earth of all celestial years. To cross the solar system on the round numbers). bodies is its satellite, the moon. So near diameter of Neptune's orbit would be a ELECTRICITY TRAVELS AT THE RATE OF 186324 MILES PER SECOND.THiS ILLUSTRATION SHOWS THE LENGTH OF TIME IT WOULD TAKE A SPOKEN WORD TO FLY FROM EARTH TO OTHER WORLDS ASSUMING WIRES WERE STRETCHED BETWEEN US AND THESE HEAVENLY B0D1ES-THE TIME FOR RADIO MESSAGES WOULD BE PRACTICALLY THE SAME. Next Time When You Are Impatient and Fretting Because "Central" Keeps You Waiting Ten Seconds for a Connection Imagine That Your Best Girl is on Neptune. You say "Hello" and It Takes Exactly 4 Hours and 2 Minutes for "Hello" to Get Up to Neptune, and Then You Have to Wait 4 Hours More to Give Your Sweetheart a Chance to Say "Hello" in Return. While If She Were on Alpha Centaun, It Would Take Your Voice Over Four Years to Get to Her and an Equal Time for Her Voice to Get Back, Altho You Know That Electricity Travels at the Rate of 186,324 Miles a Second. The unit of measurement employed for is the moon that if we should make on some journey of more than three thousand years. distances beyond the solar system is either great plain a model of the solar system in The sun's attraction reaches far beyond the light year or more recently the parsec which the astronomical unit, the distance Neptune's orbit, however. There are comets which appears to be rapidly replacing the from earth to sun, would be four hundred belonging to the solar system compelled by light year among astronomers. A "light feet, the distance between earth and moon the sun's attraction to accompany him on year" is the distance that light, with its would be only one foot. On the same scale his travels thru space that return periodi- finite but almost unimaginable velocity of the most distant planet Neptune would be cally to the immediate vicinity of the sun one hundred and eighty-six thousand miles two and one-quarter miles away. In round from regions far beyond the orbit of Nep- per second, travels in a year. It is equal in numbers the moon is distant from us sixty tune and there is also the possibility that round numbers to sixty-three thousand times the distance from the earth's center one or more undiscovered planets may times the distance from the earth to the to its surface or two hundred and forty travel around the sun in orbits exterior to sun or approximately six thousand billions thousand miles and thru our great tele- Neptune's orbit. of miles. The parsec is equal to three scopes we see it as it would appear at a Measured in terms of familiar units, such and twenty-six hundredths (3.26) light distance of one hundred miles. as are employed for the measurement of years, and it is approximately two hundred Granted that it were possible to escape distances on our own planet, the extent of thousand times the distance from the earth the earth's gravitational bonds and to travel the solar system is tremendously great. to the sun. It is "the distance of a star by our swiftest means of conveyance, the Seen from Neptune, the sun presents no with the parallax of a second." a fact which airplane, thru interplanetary space, let us appreciable disk. It is in this sense star- its name conveys to us. In other words, at consider how long it would take us to reach like to the Neptunians, but seen from Nep- the distance of one parsec the distance from the moon, sun and planets if our speed were tune the stars appear no more brilliant and May, 1919 ELECTRICAL EXPERIMENTER 25 SATURN > t I JUPITER I4j MILLION YEARS J 1539 YEARS 963 YEARS 452 YEARS MOON ALL AEROPLANES IN THIS ILLUSTRATION FLY AT A RATE --© 7 WEEKS OF 200 MILES AN HOUR NEVER STOPPING OAYOR NI6HT The Fastest Vehicle Known to Man is the Airplane. Supposing There Was Air Instead of a Vacuum Between the Earth and the Other Heavenly Bodies. It Would Take an Airplane a Very Considerable Time to Reach These Bodies. Even to the Moon, the Nearest of All Heavenly Bodies. Only 236.000 Miles Distant, Seven Weeks Would Be Consumed in Reaching It By Airplane. To Reach Neptune, It Would Take 1359 Years. Such Are the Immense Distances of the Universe. therefore no nearer than they do to us. travel from the earth to the stars with the appear to be but one second of arc apart, To Neptune the sun, tho star-like in form, velocity of light. a distance that requires the most careful supplies a very appreciahle quantity of light At this speed, one hundred and eighty- adjustment and manipulation of the tele- and heat (one nine hundredth of the amount six thousand miles per second, we circum- scope to measure accurately. We are still the earth receives) while the amount of navigate our globe in one-seventh of a sec- one light year distant from Alpha Centauri, light and heat that Neptune receives from ond, reach the moon in one and a fourth the nearest of the bright stars. A few of the nearest stars is entirely inappreciable. seconds and the sun in eight minutes. In the stars may now appear somewhat When our airplane reaches Xeptune after a little over four hours we pass the orbit brighter than they appear to us on earth, but a journey of one thousand five hundred of Xeptune and are started on our journey the majority of the stars appear just as we years, it is, as it were, just clearing the to the stars penetrating further and further see them here on earth and the forms of the ground for its flight to the stars. To cover into interstellar space. For a year we travel constellations remain practically unchanged the intervening space to the nearest star. and reach not a single star tho we are in appearance, for we are only beginning traveled by light in four and a third years, speeding ever onward with the velocity of our journey thru the sidereal universe and an airplane would require fourteen and a light. We have now covered the distance our position in the universe has only shifted half million years. In that time the solar of one light year which means the waves of in a slight degree. If we should continue system itself would be in some far distant light from the sun we have left behind must our journey to the immediate vicinity of part of the universe, for it is speeding on- travel for a year before they reach us. We Alpha Centauri. we would find that it is ward thru space at the rate of twelve miles continue our journey and find ourselves next not like our own sun. a single star, but is a second or about four astronomical units at a distance of one parsec from the sun. a binary star consisting of two suns in a year. We have traveled a distance of approxi- revolution around their common center of Changing now our unit of measurement mately three and a quarter light years, and gravity. The distance of this binary sys- that we may express interstellar distances were it possible to see the earth as well as tem from the solar system has been meas- in comprehensible numbers, we prepare to the sun at this distance, the two would (Continued on page 54) THE IMMENSITY OF DISTANCES IN THE UNIVERSE In This Illustration. We Are Trying to Convey to the Reader an Idea of the Enormous, Unthinkable Distances of the Universe. If the Dis- tance from the Sun to Neptune, Which in Reality is 2.791 Million Miles, is Represented By Seven Inches On This Scale. Then the Dis- tance from the Sun to the Nearest Star, Alpha Centauri. Would Be Slightly Over One Mile. Note How Near the Earth is to the Sun, Altho 92 Million Miles Away from It. In Order to Show the Earth Without It Touching the Sun. It Was Necessary In This Drawing to Make the Earth Smaller Than Mas. In Reality Mars is Smaller Than the Earth. The Other Planets Are Shown in Their Correct Proportions. — 26 ELECTRICAL EXPERIMENTER May, 1919 Reckimimig Metal Duasft From Ftoe refineries of different types there is the particles carried by the gases become It is stated that over 90 per cent of the INalways a possibility of some valuable electrified and are projected against the flue dust can be removed and that the value by-products, waste, etc., being lost by walls to the tubes. These tubes are ground- of the copper, zinc and other metals re- gases ascending the flue. This is particu- ed and thus the particles drop into hoppers covered will within a short time pay for larly true in the metal treating field. Here below. Mechanical rectifiers convert the the treating equipment. low voltage alternating current into direct current. An interesting appli- cation of this process was recently made in a copper refinery. In this particular installa- tion there is another noteworthy fact and that is the size of the generating and trans- forming unit used. The treater tubes containing the high ten- sion electrodes and thru which the flu gases pass are arranged in six groups. The elec- trodes are suspended at the top from a rack which provides ample insulation, and are con- This Power Plant Delivers 100,000 Volts and .5 Ampere, nected with the high Interior of High Tension, Direct Current, Electrode Direct Current, for Precipitating the Solid Particles Chamber Inside of Flue Tube Measuring 13 Feet In tension direct - current in Flue Gases, Such as in the Metal Refining Field, Diameter. The Electrodes Are Suspended Chains Thus Saving as Much as 90 Per Cent of the Flue Dust. line at the bottom. The Which Carry the Charge When in Use. gases from the furnaces it has been found possible to save solid and pass thru pipes 13 feet in diameter, a "Y" The transformers are of 40 kva. capacity, liquid particles from the flue gases by an with valves being provided so that the gases 200 volts low tension and 100,000 volts high electrical process. This consists in passing tension. To the motor-generator shafts are can be made to go either thru the treater or the gases thru tubes in which are suspended coupled the commutating rectifiers for insulated chains charged with high voltage directly to the stack as desired. See figure transforming the high-tension alternating direct current. In passing thru the tube herewith. current into direct current. ducing mechanism. The cams and levers A Gyrostatlnc Bicycle which operate the arms and head are thoroly concealed inside the body. The accompanying illustration shows a bicycle, or other device on which the spin- novel gyrostatic bicycle model built by a ning gyro is mounted. To demonstrate the London scientific instrument maker, and principle of the gyroscope—which is based this machine will maintain its equilibrium upon the fact that a spinning or rotating for a considerable period of time. Many mass tends to preserve its plane of rota- of us most probably have seen the street tion—all one has to do is to jack up the fakir shouting loud and longly about the rear wheel of a bicycle, and by turning the wonderful possibilities of the toy gyroscope, pedals, cause this wheel to spin rapidly. Now hold the bicycle off the ground a short distance, and endeavor to turn the complete bicycle sidewise. You will ex- perience a surprisingly strong counter-turn- £"Tfc » *& ing effect, which tends to keep the bicycle in its upright plane as long as the wheel spins at a fair rate of speed. Many of these gyros are electrically driven ; also it is well to keep in mind the fact that even an ordinary bicycle exerts some gyrostatic effort, and this has much to do with the success of the rider in maintaing his up- right position while spinning along on two wheels mounted in tandem, that is, one be- hind the other. You have probably noticed, if you have ever ridden a bicycle that the mIi^I faster you go, the easier it is to maintain /aW\\\\[ h$r f[\m\\ «* your balance. The increasing gyrostatic ef- fSm/A \ fect as the rotational speed of the wheels /C^feffLJ '10- increased was the reason. vrfWVJf x/- 1 A HARD DRINKER OF SOFT m DRINKS. This little girl is a soft drink demonstra- The Gyrostatic Bicycle Is Used Extensively in School Labora- tor and she sits in show windows all day tories to Demonstrate the Won- long pouring drink after drink of some derful Stabilizing Power of the delicious Gyroscope. beverage into the glass and rais- ing it to her lips and draining it with the greatest ease. She seems to like the beverage, for after and the apparatus here shown duplicates the each drink she nods her head a couple of many startling maneuvers that the little times with a happy smile which seems to twenty-five-cent toy gyro performs. When say, "My, that was good" ; then she pours a gyroscope balance wheel is spun rapidly, down another one. Drink Hearty, Little Girl. It's Only Some of and providing the rim of the wheel is suf- The figure is made life size of papier Willie Bryan's Famous Grape Juice. An ficiently heavy to give it a good momentum, mache and mounted on a tabourette, which Electric Motor Solves the Mystery of This it will be found very difficult to shift the contains the electric motor and speed re- Silent and Ever-Drinking Demonstrator. — 27 May, 1919 ELECTRICAL EXPERIMENTER Tlhese On. Your Auto ELECTRICALLY HEATED PRIMER ELECTRIC CIGAR LIGHTER FOR matically disengaged, the "starter" ti THE AUTO. nutting the driving enei magneto FOR QUICK STARTING as a flexible coupling. OF AUTOS. At last—a perfect electric cigar I The control ol the "star* r" is bj mean It should prove a l">on to motorists. It is -haft , lever mounted on a project handy and ^ from the front of the housing. The li ^^ c on\ enicnt is so constructed that it can either be • —a I w a\ rated bj hand or thru the medium of a i t h i n w control connection. reach. The The impulse starter is not an attach- burner tip ment, but is provided only as a pari of this is made of new magi heavy wire ;i i\ il will !:i-t indefi- HEADLIGHT DIMMER n i t e 1 y. \n Ohio electric concern is offering the Burner tip public a device known as a headlight dim- is protect- mer for Use on lord cars ed by a cap to dim the headlights when shown driving at night. This incut. This it is claimed by Ever Try to Light a Cigar dimmer, While Driving an Auto? This neat a n run y NIKOLA TESILA Written Exclusively for The Electrical Experimenter since the announcement of proved appliances. Similar phenomena were application of these radiations for the pur- EVERMaxwell's electro-magnetic theory noted, greatly magnified in intensity, but pose was quite obvious. When Dr. Hertz scientific investigators all the world they were susceptible of a different and was asked whether such a system would over had been bent on its experi- more plausible explanation. I considered be of practical value, he did not think so, mental verification. They were con- this so important that in 1892 I went to and he was correct in his forecast. The vinced that it would be done and lived in Bonn, Germany, to confer with Dr. Hertz best that might have been expected was a an atmosphere of eager expectancy, un- in regard to my observations. He seemed method of communication similar to the disappointed to such a degree that I re- gretted my trip and parted from him sor- rowfully. During the succeeding years I Lorn resistance morn* made numerous experiments with the same object, but the results were uniformly nega- Alternator Friction Device ^<^S tive. In 1900, however, after I had evolved a wireless transmitter which enabled me to obtain electro-magnetic activities of many Lour resistance. millions of horse-power, I made a last des- perate attempt to prove that the disturb- /Reciprocating piston ances emanating from the oscillator were '**************************************r. ether vibrations akin to those of light, but Bigt met again with utter failure. For more than TTt-rTrr-r-rt-fTrt-mt-rrrrrrrrnrmzzi, eighteen years I reading have been treat- Friction Device ises, reports of scientific transactions, and <*j**************f*************r*r*y. articles on Hertz-wave telegraphy, to keep p.s.. Capacity 10 Big main Alternator of 10,000 Cycles myself informed, but they have always im- K.W., Which Was Employed by Tesla in His >****r*r******************************m*9* First Demonstrations of High Frequency prest me like works of fiction. Phenomena Before the American Institute of The history of science shows that theo- Electrical Engineers at Columbia College, ries are perishable. With every new truth May 20, 1891. Fig. 1. Electric Transmission Thru Two Wires and that is revealed we get a better under- Hydraulic Analog. Fig. 3. usually favorable to the reception of any standing of Nature and our conceptions evidence to this end. No wonder then that and views are modified. Dr. Hertz did not heliographic and subject to the same or the publication of Dr. Heinrich Hertz's re- discover a new principle. He merely gave even greater limitations. sults caused a thrill as had scarcely ever material support to a hypothesis which had In the spring of 1891 I gave my demon- been experienced before. At that ^^^^^ ^^^^^ strations with a high frequency time I was in the midst of press- machine before the American In- ing work in connection with the stitute of Electrical Engineers at /N this remarkable and complete story of his discovery of the introduction of my Columbia College, which laid the commercial "True Wireless" and the principles upon which transmission system of power transmission, foundation to a new and far more and reception, even in the present day systems, are based, Dr. but, nevertheless, caught the fire promising departure. Altho the Nikola Tesla shoivs us that he is indeed the "Father of the Wire- of enthusiasm and fairly burned laws of electrical resonance were less." To him the Hertz ivave theory is a delusion; it looks sound with desire to behold the miracle well known at that time and my from certain angles, but the facts tend to prove that it is hollow eyes. According- lamented friend, Dr. John Hop- with my own and empty. He convinces us that the real Hertz waves are blotted ly, as soon I had freed myself kinson, had even indicated their as out after they have traveled but a short distance from the sender. of these imperative duties and specific application to an alterna- It folloivs, therefore, that the measured antenna current is no indi- resumed research work in my tor in the Proceedings of the In- cation of the effect, because only a small pact of it is effective at laboratory on Grand Street, New stitute of Electrical Engineers, a distance. The limited activity of pure Hertz wave transmission York, I began, parallel with London. Nov. 13, 1889, nothing and reception is here clearly explained, besides showing definitely high frequency alternators, the had been done towards the prac- that in spite of themselves, the radio engineers of today are construction of several forms of tical use of this knowledge and employing the original Tesla tuned oscillatory system. He shows apparatus with the object of ex- it is probable that those experi- by examples with different forms of aerials that the signals picked ploring the field opened up by ments of mine were the first pub- up by the instruments must actually be induced by earth currents— Dr. Hertz. Recognizing the lim- lic exhibition with resonant cir- not etheric space waves. Tesla also disproves the "Heaviside layer" itations of the devices he had cuits, more particularly of high theory from his personal observations and tests. employed, I concentrated my at- EDITOR. frequency. While the spontane- tention on the production of a ous success of my lecture was powerful induction coil but made due to spectacular features, its no notable progress until a happy chief import was in showing that inspiration led me to the invention of the been long ago formulated. It was a per- all kinds of devices could be operated oscillation transformer. In the latter part fectly well-established fact that a circuit, thru a single wire without return. This of 1891 I was already so far advanced in traversed by a periodic current, emitted the development of this new principle that some kind of space waves, but we were in ignorance as to their character. I had at my disposal means vastly superior He ap- -^7 \~^\/>iiv»a*or parently an experimental titan frequency gave proof that rt/ternator they were transversal vibrations in cycles. the frtctich Device laOOQ ftdjustoblc condenser] ether. Most people look upon this as his High tension great accomplishment. it to secondary To my mind Leads lecture room \6ro<.-rrd Adjustable seems that his immortal merit was not so | primary i.nOuctance £iastic nuoH r ^#*-l* much in this as in the focusing of the in- Qectprocvnng pis too. Illustrating the Diagram Circuit Connections vestigators' attention on the processes tak- and Tuning Devices Employed by Tesla in His Experimental Demonstrations Before the ing place in the ambient medium. The American Institute of Electrical Engineers Hertz-wave theory, by its fascinating hold the High With Frequency Alternator Shown on the imagination, has stifled creative ef- in Fig. 1. Fig. 2. fort in the wireless art and retarded it for Electric Transmission Thru a Single Wire to those of the German physicist. All my twenty-five years. But, on the other hand, Hydraulic Analog. Fig. 4. previous efforts with Rhumkorf coils had it is impossible to over-estimate the bene- left me unconvinced, and in order to set- ficial effects of the powerful stimulus it was the initial step in the evolution of my tle my doubts I went over the whole ground has given in many directions. wireless system. The idea presented itself once more, very carefully, with these im- As regards signaling without wires, the to me that it might be possible, under ob- May. 1919 ELECTRICAL EXPERIMENTER 29 radical impro table number of '- ' 'opacify ft-l J » C .» *»"•« */***,. dilators had first to I faonant energy oi these bad to b< transformed in transmitters and collected . Sueli t^-C I _i*_ a nianitc stly I lllustratlng Typical Arrangements for Id be cii in Collecting Energy In a System of Trans- its i it all extrani Wi mission Thru a Single Wire. Fig. 5. I ii . d. In time, hi iwever, n sen nee, that devices of this kind, to be in n to transmit el LTth, thus dispensing with all artificial con Elevated capacity Elevated capacity one who might wish to examine in Tesla's System of Wireless Transmission* Thru the Earth as Actually Exposed In tially tli' His Lectures Before the Franklin In- must not view it in the light oi present day stitute and Electric Light Association In nee. 1 only need to say that as lal February and March, 1893. Fig. 8. Alternator Receiver due regard to the physical properties of ; Small capocity Small capacity IV. !: !".1;:J this planet and the electrical conditions y —... node . The Forerunner of obtaining on the same. I will briefly touch the Audion — the C upon the salient advances as they were ..X-.._____ Most Sensitive made in the gradual development of the Detector system. Wireless as De- The high frequency alternator employed Known, scribed by Tesla In in my first demonstrations is illustrated in His Lecture Before ^ fig. 1. It comprised a field ring, with 384 the Institution of pole projections and a disc armature with E lectrical Engi- coils wound in single layer one which were neers, London, connected in various ways according to re- capacity X February, 1892. Small quirements. It was an excellent machine Fig. 9. Large capacity for experimental purposes, furnishing sinu- soidal currents of from 10,000 to 20.000 Elucidating Effect of Large Capac- Diagram cycles per second. The output com- ity on One End. Fig. 6. was paratively large, due to the fact that as section, the alternator by an oscillating Resonance." This little salvage from the much as 30 amperes per square millimeter piston and the filament of an incandescent wreck has earned me the title of "Father could be past thru the coils without injury. lamp by a minute channel connecting the of the Wireless" from many well-disposed The diagram in Fig. 2 shows the circuit pipes. It will be clear from a glance at fellow workers, rather than the invention arrangements as used in my lecture. Reso- the diagram that very slight excursions of scores of appliances which have brought nant conditions were maintained by means of the piston would cause the fluid to rush with high ve- wireless trans- . . mission within locity thru the small channel the reach of System orammurn) wkdaxonssmmutoKsaim in tesla's u s patent every young McSnnerfStfi.zzitXMiamsPONWBiiUKintmt m mitussmnsrt/ssion and that vir- tually all the amateur and /tdjusloble Inductance Primary Condenser which, in a -|_ tVlofUSS energy of WIRELESS RECEIVER time not dis- TRANSMITTER movement Inductance /3djuslBb/e \ be tant, will lead Source ofimpulses of would to undertak- arbitrary frequency t r ansformed t Tunedsecondary mth into heat by ings overshad- adjustable capocity owing in mag- friction, simi- larly to that n i t u d e and Circuit controller fflpiiigT importance all synenranism mm impulsespulses x^ loootioooo of the electric past achieve- Ty *jlSLSLSl$Sl31i current in the ments of the lamp filament engineer. The second The popular the fix//? tuned c/Rcu/rs ofabove diagram sho/th SEP/IRATELY diagram will impression is HI now be self- that my wire- e x p lanatory. Adjustable inductance /djuStobte induckm Corresponding less work was TransformingGrruit 'tt> " Stmi/atiy funed begun in 1893, CiKfatzJng circuit tjisup to the termi- Transforming circuit fH> plying osci/tanans of . Discharge circuit May, 1919 30 ELECTRICAL EXPERIMENTER modified substance, is the system of today and I am resulting in the generation of heat as in the tions of the oscillator might be of a single authenticated in- incandescent lamp. Theoretically consid- thru the immense extent of the globe the not aware stance of successful transmission at con- ered, the efficiency of conversion of energy principles involved are the same. of such a con- siderable distance by different instrumen- should be the same in both cases. Consider now the effect ex- talities. It might, perhaps, not be clear to Granted, then, that an economic system ductor of vast dimensions on a circuit of Fig. il- \ of power transmission thru a single wire is citing it. The upper diagram 6 a Imest system com- lustrates a familiar oscillating //>>-'" prising a straight rod of self-inductance 2L ~-~<<\\ with small terminal capacities cc and a node in the center. In the lower diagram of the is attached to the , figure a large capacity C rod at one end with the result of shifting the node to the right, thru a distance cor- " to self-inductance X. As both i responding I I ! L =4-Qn t4-qn„ \\\\\ parts of the system on either side of the \J Tesla's four circut t B- node vibrate at the same rate, we have evi- from tuned mreJess system dently, (L + A") c - (L — X) t ^ 't^^k* '. ^\ ^S, ^-\ C — c . the ca- which A' = L When Fig. 14. Diagram Explaining the Re- C + c lation Between the Effective and the Current in the Antenna. pacity C becomes commensurate to that of Measured the earth, X approximates L, in other those who have perused my first descrip- words, the node is close to the ground con- tion of these improvements that, besides nection. The exact determination of its making known new and efficient types of position is very important in the calcula- apparatus. I gave to the world a wireless certain terrestrial electrical and tion of system of potentialities far beyond any- geodetic data and I have devised special thing before conceived. I made explicit means with this purpose in view. My original plan of transmitting energy 9 without wires is shown in the upper dia- Q one illus- gram of Fig. 7, while the lower 6 mechanical analog, first publisht trates its Grounded oscillator Magazine of Hertz oscillator of in my article in the Century great energy ineffective ofsmall energy June," 1900. An alternator, preferably of highly effective ftertz wave system high tension, has one of its terminals con- nected to the ground and the other to an elevated capacity and impresses its oscil- a distant point ' the' earth. At • • lations ' upon — ' ,„bj ' > — - - j.rt /./ / » — a receiving circuit, likewise connected to ground and to an elevated capacity, collects Fig. 15. Illustrating One of the General Evi- Transmission. some of the energy and actuates a suitable dences Against the Space Wave \H device. I suggested a multiplication of I contem- and repeated statements that such units in order to intensify the effects, plated transmission, absolutely unlimited as In an idea which may yet prove valuable. to terrestrial distance and amount of en- provided, the analog two tuning forks are ergy. But, altho I have overcome all ob- the re- one at the sending and the other at stacles which seemed in the beginning un- ceiving station, each having attached to its surmountable and found elegant solutions Tesla's Four Circuit Tuned System Con- lower prong a piston fitting in a cylinder. which confronted me, Hertz- of all the problems trasted With the Contemporaneous cylinders communicate with a wave System. Fig. 11. The two yet, even at this very day, the majority of with an incom- large elastic reservoir filled experts are still blind to the possibilities practicable, the question arises how to col- which are within easy attainment. lect the energy in the receivers. With this -:%. My confidence that a signal could be object attention is called to Fig. 5, in which easily flashed around the globe was a conductor is shown excited by an oscil- strengthened thru the discovery of the "ro- lator joined to it at one end. Evidently, as tating brush," a wonderful phenomenon the periodic impulses pass thru the wire, which I have fully described in my address differences of potential will be created along before the Institution of Electrical Engi- the same as well as at right angles to it neers. London, in 1892, and which is illus- either of in the surrounding medium and trated in Fig. 9. This is undoubtedly the these may be usefully applied. Thus at a, known, but rHAHS/iirrEH most delicate wireless detector a circuit comprising an inductance and ca- it hard to produce and iKrti *mes ejCiicr for a long time was in trans- •' pacity is resonantly excited the I'll-' to maintain in the sensitive state. These the longitudinal sense. rfinugheorJi verse, and at b, in difficulties do not exist now and I am look- circuit parallel Diagram Exposing the Fallacy of the Gliding At c, energy is collected in a ing to valuable applications of this device, Wave Theory as Propounded in Wireless to the conductor but not in contact with it, Text Books. Fig. 13. particularly in connection with the high- and again at d, in a circuit which is partly speed photographic method, which I sug- be, or sunk into the conductor and may pressible fluid. The vibrations transmitted gested, in wireless, as well as in wire, trans- not, electrically connected to the same. It to either of the tuning forks excite them mission. disposi- is important to keep these typical by resonance and, thru electrical contacts Possibly the most important advances dur- the distant ac- tions in mind, for however or otherwise, bring about the desired re- ing the following three or four years were sult. This, I may say, was not a mere my system of concatenated tuned circuits mechanical illustration, but a simple rep- resentation of my apparatus for submarine signaling, perfected in 1892, but not Tm> forms ofgrounded circuits equally effective TmnsmnYing by me Circuit appreciated at that time, altho more effi- Forms of Receiving Circuits cient than the instruments now in use. The electric diagram in Fig. 7, which '-" '" i from lecture, was t.'W^;'>/p»7'W til- 'tr? > "I'r- was reproduced my meant only for the exposition of the prin- ciple. The arrangement, as I described it Transmitting Circuit deceiving Circuit in detail, is shown in Fig. 8. In this case connected to twopoinh on one grounded primary of a Transmitter Transmitter or receiver — .of the ground or both ends an alternator energizes the transformer, the high tension secondary of which is connected to the ground and an -*—. -?~-~— elevated capacity and tuned to the imprest Relative oscillations. The receiving circuit consists Fig. 16. Showing Unimportance of of Transmitting and Receiving An- of an inductance connected to the ground Position tennae in Disproval of the Hertz-wave and to an elevated terminal without break Theory. and is resonantly responsive to the trans- and methods of regulation, now universally mitted oscillations. A specific form of re- Arrangements of Directive Circuits adopted. The intimate bearing of these in- Patent No. ceiving device was not mentioned, but I Described in Tesla's U. S. ventions on the development of the wireless 613,809 of November 8, 1898, on had in mind to transform the received cur- Con- art will appear from Fig. 10. which illus- "Method of and Apparatus for rents and thus make their volume and ten- trolling Mechanism of Moving Ves- in 'Continued on page 61) sels or Vehicles." Fig. 12. sion suitable for any purpose. This, May. 1919 ELECTRICAL EXPERIMENTER 31 Novel (Gemierators 1.\l V.IXK yourself wearing a landing gear of each plane, »o that the air inally mounted on a light metal frame ivers ;uhI a telephone transmitter h" of the propeller drives a -mall . mg a voltmeter fuses and terminals, and listening to a ing, "/ am two blade wooden tan on the generator ently an aluminum i ase v. as right over R 7 and your shells ore all burst- shaft. Thus the generator runs when* developed which was watertight when ing 'short.' Increase range SO yards" That plane is in motion, and also while it is 1. Ml the switch) was the experience of American radiooper- on tl 1 with th<_- engine running. mounted ii Ground Officers of the U. S. Army Talking to Airplanes In Flight by Means of Wireless Telephone. The Range of Such Communication Has Recently Been Increased to 150 Miles by Official Test. Above:—Spring Cradle Suspension of the Wireless Generators Used on U. S. Naval Submarine Chasers and Destroyers, to Eliminate the Trans- mission of the Humming Sound Produced by Their Operation, to the Steel Hull of the Vessel and Its Subsequent Interception by a Lurking U-boat. The Sub-sea Sound Detector Used by the German Submarines Was so Sensitive That This Precaution Was Necessary. At Right:— Lower Right-hand View Shows the Wind-driven Airplane Radio Generator Developed During the War. Its Speed, of Course, Varies with the Velocity of the 'Plane and How Its Voltage Is Maintained Constant with Variable Speed Is One of the Interesting Problems That Radio Engineers Had to Solve Before Anything Else Could Be Done. ators during the latter part of the war, for Constant voltage with variable speed is se- A submarine chaser often lies motionless, radio telephone sets were developed that cured by an ingenious arrangement of dif- waiting for a U-boat to stick its nose above enabled men on the ground to talk with air- ferential fields controlled by a two-element the surface. So sensitive are the listening planes flying over the enemy lines and aim vacuum tube mounted in the stream-line devices on the submarines that even the the guns according to their directions. housing of the generator. slight hum of one of these dynamotors, An essential feature of the radio tele- At stations on the ground or on ship- transmitted to the chaser hull, would be- phone set is a small generator to deliver board, power is taken from storage bat- tray its position. Hence the dynamotors direct current at from 275 to 350 volts. For teries, and here a small dynamotor, driven furnished to the Navy are mounted in a airplane use. these generators also delivered by 10-volt current, gives the required high cradle of coil springs as here illustrated. current at 25 volts. One is mounted on the voltage. In the field one of these sets was Photos courtesy Westinghouse li. & M. Co. Boosts Sifitaals 1,000,000 Times The six-step audion amplifier set here French armies was in part due to the won- on the various battle-fronts. Amplifiers shown represents the latest development in derful results achieved with such amplifiers using as many as nine steps were employed amplifiers, and its intensifying with marked success in trench qualities are enormously in communication, aerial com- excess of any similar appa- munication, and similar work. ratus produced heretofore. In the lower left-hand cor- Under ordinary conditions, ner of the panel is mounted a this set will amplify 1.000,000 simple two-way switch, by times, so it is especially well means of which the first bulb adapted for use in connection can be made either a detector with the reception of the very for radio signals or the first- weak signals set up by the step amplifier for audio-fre- small portable transmitters quency currents. When used used in modern warfare. As as a detector, the connections a matter of fact, the set has from the tuner are made to been designed strictly with an the upper pair of external eye towards military field binding posts. When used as work, and similar purposes, an amplifier, the connections and has already proved its ef- from the detector (or the ficiency along such lines. An two-ground terminals, in case entirely new departure in de- one is receiving conduction or sign is seen in the fact that induction currents thru the only one "A" battery, and one earth) are made to the lower "B" batten - are employed. In pair of external binding posts. addition, these batteries are To the other pair of binding practically free of adjustment, posts is connected the six-volt which greatly enhances the storage battery. value of this set, and is a The telephone cord ter- unique feature in amplifier minates in a plug, which can construction. be plugged into the third, In connection with the above fourth, fifth or sixth jack The Most Powerful Vacuum Tube Amplifier Now Standardized and Built. apparatus, it cord to the degree of ampli- may be men- It Is a Six-stage Amplifier and Possesses an Amplifying Power of tioned that the success of the 1,000,000 Times. It Solved Many Knotty Problems During the War. fication which is desired. 32 ELECTRICAL EXPERIMENTER May, 1919 Adopts MunMiplex Rsidli® THE recent announcement that the ing of eight different messages on one wire radio outfit. By this new system Secre- Government had decided to adopt the at the. same time. Thus it may be seen tary Daniels is able to keep in communica- multiplex system of radio telegraphy what a great advantage it holds over the tion with several vessels out at sea at the time. Likewise, and telephony, makes possi i entirely old method of Morse telegraphy. same President Wilson, on new methods of communication. Radio messages are sent by the same his voyage to France, was able to keep in The multiplex radio system is a complex method. The trans-Atlantic Radio Room immediate communication with Washing- one. The multiplex system of ordinary in the Navy Department illustrated here- ton. telegraphy permits the sending and receiv- with is completely equipt with a multiplex This photograpli is the first to be re- leased showing the trans-Atlantic Radio Operating Room of the Navy Department. This is the receiving room of the radio station in the Navy Department. Four re- ceiving machines constitute, with the four perforating machines, one complete unit of multiplex radio-telegraphy. As a result, four messages may be sent and four re- ceived over one antenna at the same time. RADIO LINKS 3,000 MILES BE- TWEEN OMSK AND LYONS. Omsk, in which are centered the hopes for the rebuilding of a new Russia, after months of isolation, is now actively in wire- less communication with the outside world. Hourly reports, containing a complete news service, are received in Omsk direct from the French wireless station at Lyons, France. Outgoing communication will be inaugurated soon. From Omsk to Lyons is 3,000 miles on a direct air line over Bolshevik Russia and Central Europe. Omsk is about midway between the Atlantic and Pacific oceans. AN OMISSION. We wish to state that credit for the photographs accompanying the article en- titled "The City of Splendid Night" by Amos Stote, publisht in the January, 1919, issue, should have been given to the A Recent Photo Taken of the U. S. Navy Department's Trans- Atlantic Radio Operating New Room. Multiplex Radio Signaling Is Now Carried on in Both Directions across the Ocean. York Edison Co. New Freimclh dirndl Ainmeinicaini Aundlnoims UNDOUBTEDLY the radio amateur is stated on good authority and experimenter has often wondered that during the war the what form of audion or vacuum de- French Government manu- tector and amplifier was being used both factured five thousand of by the American and European armies. these audion bulbs even- Thru the courtesy of Dr. Lee de Forest, we day, or almost two million are enabled to show herewith the standard of them in a year. This form of three-electrode audion in use by rate of audion production the French Army signal corps, as well as was carried on during the by the French Navy, and also the standard last two years of the war. form of three-electrode audion in use by The French bulb here # the United States Army Signal Corps. shown is particularly in- As we have heard but very little concern- teresting as being efficient ing the French and other European wire- and suitable in all three less apparatus for several years, owing to functions, — detector, am- the war conditions existing, we rind consid- plifier and oscillator. erable interest in the French type of The Standard United vacuum bulb detector and amplifier, and so States Army type of three- we will consider it first. electrode audion here As the illustration show's it comprises a shown comprises filament, spherical form of glass bulb, which is grid and plate, rigidly se- eventually pumped out to a very high de- cured in place in the man- gree of vacuum. One thing decidedly no- ner indicated. Particular ticeable about both the French and Ameri- attention has been given in can tubes, is the simplified and highly im- this design to the manner proved form of base which incorporates of supporting the inverted four contact pins, which form a juncture "V" type filament as well with four sockets in the bayonet-joint re- as the grid and plate ele- ceptacle supporting the audion. Two of ments, so that as a matter At the Left— U. S. Army and Navy Type de Forest Audion. the contact pins lead to the incandescent of fact these rugged bulbs At Right—the Famous French Type of Three Electrode Audion, Five Thousand filament, while the other two connect to the can be handled without of Which Were Manufactured Every Day during the Last Year of the War. It Serves as Detector, grid and the plate respectively. It is thus any particular pains, and Amplifier and Oscillator. but a moment's work to snap a bulb out of none of the electrode ele- its socket and replace it with another one. ments can move as they could in the older the top of the filament is anchored and sup- The French audion is unique in its gen- types. A still better construction is in- ported by a third wire secured in the glass eral design, as will be noted from the ac- volved in a modified and improved form stem. There is still a slight chance for a companying illustration, the filament being of audion being developed for the United little movement between the electrode ele- in the form of a fine straight wire passing States Signal Corps by Dr. de Forest. It ments in this detector, and in the improved thru the center of the grid, which takes the will be seen how the plate member is bent form aforementioned and which is now form of a helical coil of non-oxidizing wire. into the shape of an inverted "U" and being developed and perfected, the filament, Outside of the helical grid, we find the rigidly secured by two wire members se- grid and plate are still further strength- wing or plate element, which is made in the. curely molded or fused into the glass ened, so that no matter how much the bulb form of a small cylinder or tube. Each of stem. The fine wire grid i; securely is jarred or shaken, no variation whatsover the three distinct elements comprising the mounted in place inside of the plate mem- can occur in the spacing between any two audion are spaced about 3/32 inch apart. It ber on two upright wire legs as shown, and of the three electrodes. — May. 1919 ELECTRICAL EXPERIMENTER 33 New Regeimeirailnve Vacwunnm By SAMUEL D. COHEN RING tin- war tin- vacuum tube very essential to note that the filament coil Dl has gone into very extensive use in line should be tapt off exactly at the cen- radio communication and other tei "i 'oil I. in order to ? results, allied electrical fields. The regener- is done in order to equalize the po- ative circuits used until now have tentials between the grid and plate circuits. been found satisfactory. However, certain Coil Li can be made as a variometer as improvements were discovered and it is will be shown later. Condenser C the privilege of the writer tn give the re- regular oscillatory secondary tuning con- sults of some of these improvements that denser. The R is a grid leak- were made on regenerative vacuum tube cir- resistance and its magnitude depends cuits for the reception of long distance Sta- upon the operating characteristics of the tions using long wave lengths. tube. One of the schemes tried by the writer A similar circuit to that of Fig. 1 is was to couple the grid to the plate of the shown in Fit;. 3, and needs no comment. vacuum tube directly in the antenna system In Fig. 4 is shown another circuit for of the oscillating circuit, in order that hete- This Circuit for a Regenerative Vacuum accomplishing the necessarv results for re- Tube Is Similar to That Given in Fig. 2, rodyne method of reception might he ac- generative effects for better efficiency. It will and Needs no Special Comment. complished with maximum efficiency. For be noted that the inductances L. and I. •his work it was essentia! to construct a a variometer. The coupling of both of comprise a variometer secondary coupled oupled magnetic system in order to accom- these coils can be changed at will, both to the primary La. The inductance L. is plish the desired effects and the accom- within the main primary and outside of the coupled magnetically to the antenna in- panying photograph shows a special type primary. This was essential in order tip ductance Li and to inductance Ls, which of inductive coupler utilized turnout these eliminate the use of switches for the con- comprises another variometer of both L. experiments. It will be noted from the trol of the inductance of the coils. and Ls. coupled magnetically to the plate The coils were built with great care, in and eing circuit of the vacuum tube. Ion- order to eliminate the undesirable oscilla- tions produced within the coil circuits, due to the inherent distributed capacity of the coils. Audion A circuit giving remarkable results in am- plifying received signals is that shown in Fig. 1. The main inductance L, is the main primary connected in series with the small coil wound on the same tube Li, which is thereafter connected to the ground as in- dicated. L-j and L., which comprises the secondary of the coupler are connected in a variometer manner as indicated. The joint point of these coils is connected to the filament terminal of the vacuum tube I nullum J I II The end of the coil is linked to the battery B, of the plate, while coil L_> is connected Fig 4 to the tertiary coil L., which coil is the one mounted on the moving arm as indi- cated on the right of the photograph. Coils Ls and L, are coupled magnetically and electrostatically thru the condenser CY It will thus be seen from the diagram that the plate and grid are coupled thru the in- ductance La and which said inductance is coupled to the antenna system La. A cri- tical adjustment is necessary between L. and Ls, and between L. and La, to give maximum radio frequency amplification in the circuit. Condenser C 3 has a magnitude of the order of two microfarads and is used in general to permit the high fre- quency current to readily pass to the plate. Another circuit is shown in Fig. 2. which Another Regenerative Circuit Resembling In This Audion Circuit, the Plate and Grid excellent results. In this circuit, the Fig. 4. Here the Radio Frequency Bridging Are Coupled Magnetically Thru Coil L., and Condensers C, and C, Are Used to Permit the Central Tap Should Be Accurately Taken plate and grid are coupled magnetically Radio Frequency Currents to Pass Freely to Off. thru coil I... In this particular case, it is the Plate. 34 ELECTRICAL EXPERIMENTER May, 1919 minnieinitts f Woolp Cotttoim amdl ILiimeini y ALBERT W. WIILSDOM The Two Long Illustrations on This Page Show How Various Textiles Such as Cotton, Silk, Linen, Etc., Look Under the Microscope. Microscopic Examination of Such Textiles is Considered One of the Best Methods of Determining Just What a Certain Fabric is Com- posed of. Microscopic Drawings of the Various Fabrics Shown In the Illustration Above are:— 1 —Cotton, 2—Wool, Various Kinds, 3—Silk, 4— Linen, 5—Hemp, 6—Cotton and Linen Mixed, 7—Cotton and Wool, 8—Cotton and Silk, 9—Shoddy, Made from New, Fine, Blue Worsted Clips. order that the layman may be more TABLE FIBERS, under which heading namely—those obtained by mechanical dis- INfamiliar with methods of making quick appear Cotton, Flax, Hemp, etc., and ANI- integration alone from the clippings, and and accurate tests of varied textiles, MAL FIBERS, as Wool and Silk. second, those fibers that are obtained from this article is written, and not with an COTTON appears under the microscope rags that have been carbonized. It thus be- object of a complete treatise on "Tex- as a wide band, generally twisted, as shown comes necessary to consider first the result tile Testing," which work in its entirety in Fig. 1. Chemically, cotton fiber, sep- of a purely mechanical operation, and in may be written in several volumes. arated from all impurities, may be looked the latter case, combined chemical and A person buying a piece of material, let upon as pure Cellulose, similar in composi- mechanical operations. Naturally, we con- tion to the Cellulose in starch. Ordinary raw cotton is not pure Cellulose, containing as it does, various impurities such as wax, oil, coloring matter, water and about 1 per cent, of mineral matter. The appearance of various kinds of WOOL under the microscope is shown in Fig. 2. Wool differs very considerably in chemical composition from Cotton and Flax. It consists of horny-matter (Kera- tin), Carbon, Hydrogen, Oxygen, Nitrogen and Sulfur. This composition is strikingly noticed when wool is burnt, accounting for the peculiar and disagreeable smell of burning horn which is given off. Boiling Caustic Soda or Potash solutions dissolve Wool, and if Acetic Acid in excess is added to the solution obtained Hydrogen Sulfid is given off. SILK, under the microscope, exhibits no definite structure, but consists of cylindrical or flattened, sometimes helical, compact threads, having the appearance of a smooth cylinder without any contents. Fig. 3 de- picts Silk as seen under the microscope. Chemically, Silk is composed of silk gela- tine, silk fiber, with fat, coloring matter and mineral substances. Fig. 19. The Burning Test Applied to Vari- Fig. 20. This Shows Apparatus Arranged for ous Cloth Materials to Determine Their Com- FLAX-LINEN fibers consist of chemi- the Accurate Testing of Cotton and Wool position, Particularly the Presence of Wool. cally pure Cellulose, and are of regular Content of Cloth, and One That is Used By Vegetable Fibers May Be Readily Distin- Practically All Commercial Cloth Testers. thickness. The cells are built up in a reg- guished from Animal Fibers By Burning, One Glass Contains a Solution of Caustic ular Animal Fibers Such as Silk and Wool Giving manner, cylindrical in shape, having Potash, or Caustic Soda, Into Which is Im- Off the Smell of Burnt Horn. They Do Not nodes arranged at regular intervals as mersed a Sample of the Wool to Be Tested. Fire Like Vegetable Fibers, But Cease to A Precipitat Indicates shown in Fig. 4. the Relative Amount Burn When Removed from the Flame. Veg- of Cotton and Other Substances Present. etable Fibers Give Off a Slight Odor of In HEMP the cells are very irregular in Likewise When Cotton is Immersed in an Burnt Wood Ignited, and They Burn When form, and do not possess nodes as in the Acid, a Precipitat Will Show the Relative Away Very Rapidly With a Flash, leaving No Amount of Adulterants. See Also Fig. 7. Hard Cinder, But a White or Gray Ash Only. former case. The cell walls are not of such constant thickness as Flax, and the ends of sider whether the chemical operation of us say for a suit, does not want to feel that the fibers are blunt, having thick walls, fre- carbonizing has in any way altered the he is being imposed upon by having in- quently branching laterally. fibers so that they might differ microscopi- ferior substitutes sold him he when believes SHODDY is old woolen or worsted ma- cally from those treated only mechanically. it is all wool. He must, therefore, have terials, torn to pieces by a machine having Pure wool, when first sheared from the immediately available some means of test- spiked rollers, which reduces them to sheep, shows that the fibers are terminated ing. fibers. They are then cleaned, and the fiber at one end with a slightly rounded point, Textiles may be separated into two main spun with a certain proportion of new wool. while the other end shows a more or less divisions, as we may call them. VEGE- Broadly, shoddy fibers are of two kinds. (Continued on page 79) Microscopic Appearance of Various Fabrics Under Microscope. Continued. 10—Shoddy, Made from New, Fine, ^oddy, Made from Black Worsted Clips, cVT^ Carbonized Brown Serge, 12—Shoddy, Made from Brown Serge That Has Been Carbonized and Subsequently r M e 8 U e er9 hat la d e n First Carbonized, Then Stript, and Afterward Dyed Green, 14-Shoddy, from fhe Sa m^i^rh6atCh = s« Th,ha t ^^unShOW n„ T? 121 ! lExceptt ThatTu! ? u 9 ' It Has Been Dyed a Full Red, 15—Originally a Brown Serge hI» f^ -r , c? T. "J rf' ^ That Had Been Car- bonized, Then Stript, Afterwardh Dyed a Deep Orange, and Finally Garneted, 16—Shoddy, Made from Carbonized, Brown Serge Which Had Been Stript and Dyed Olive Shade, 17—Shoddy, Made from Various Knit Goods of Different Colors, 18—Shoddy, Made from Serges That Were Carbonized, Stript and Dyed a Deep Maroon. May. 1919 ELECTRICAL EXPERIMENTER 35 xpemunmeimtts nmi aoiiO' By IVAN CRA PART III. the last article ionization by a-rays spread it evenly over a photographic plate. glued. Just above this screen and with its INwas discust. The radiations of radium After a long exposure the plate will be end about over the middle of it, a small also possess the property of affecting to be affected, watch hand is secured. To the extremity photographic plates. This action 01 Xiewcnglow ski has shown that phos- of this a small quantity of radium salt is radio-active substances is essentially an phorescent calcium sulfid after being ex- ionizing property and the effect produced is posed to sun-light, assumes the power of emitting beta particles. These particles are extremely penetrating, and are capable of affecting photographic plates even thru comparatively thick sheets of intervening metal. This property, however, differs from ordinary radio-activity. The sun- light seems to cause a disintegration of the calcium atom, causing an emission of beta raj s. Much better radiographs may be ob- tained if the ionizing agent is the active portion from a spinthariscope. This is a wonderful little instrument and should be in the hands of every experimenter of radio-activity. the great va- Arrangement of Plate and Uranium Salt Considering In Taking Radiographs. riety of experiments which may be per- formed with it, and the comparatively small Radiograph of Key and Pen Point proportional the ionizing power of the sum for which it may be procured from to Taken with Radium Ore. Exposure substance. several leading houses, the experimenter, if Three Days. Both the a and h panicles ionize the air at all possible, should possess himself of thru which they pass; however, the a-parti- one. It is, while being an extremely inter- fastened. In some spinthariscopes the arm c!es do this to a larger extent. In fact the esting and instructive apparatus, a very which supports the active substance is re- total number of ions per sec, due to the simple one. In its common form it some- movable, allowing it to be utilized in the complete absorption of a-rays from one what resembles the eyepiece of a micro- making of radiographs. Those, however, gram of radium, is 2.56 X which are fitted with sta- 10", while the beta rays tionary arms or those in from the same amount of which the active substance radium produce only 9 X is placed directly on the 10". It will be seen from screen, may be employed by this that the a-rays would removing the lens portion affect the plate to a much and using the case alone. greater degree than the b- When using a spinthari- rays. This is only true when scope for making radio- there is no obstruction be- graphs the exposure need tween the substance and the only last about two days. plate. When a solid is in- This is because of the much terposed the effect is ac- greater activity of the sub- con plished almost entirely stances used in the construc- by the b-rays on account of tion of these instruments. their greater penetrating If figures such as letters be power. cut from heavy lead foil or Geitel, and afterwards Method of Preparing Radium in Tubes For Use in Medical Work. The Three some metal sheet and inter- Becquerel and Mme. Curie Small White Tubes Contain Radium Sulfate and Have Respectively 2,550 and posed between the spinthari- 100 Milligrams of Radium Element Content. Beside them Are the Silver showed that the b-rays and Platinum Screens Used, Back of Which Is the Brass Carrying Tube, scope element and the plate, were subject to magnetic Together with a Package Ready for Shipment. their shadow will be clearly- deflection. The experi- discernible. Many interest- ments conducted by Kaufmann and Bec- scope. The distal lens is removed, and in ing photographs may be made in this man- querel have shown that the b-particles con- its place is put a metal plate upon which a ner. The author has found that it is imprac- sist of negatively charged particles pro- thin layer of phosphorescent zinc sulfid is tical to attempt the construction of such an jected with an exceedingly high speed, in- instrument as they are more cheaply bought. deed almost approaching that of light. These Of course there are many variations of the experiments also proved their mass was experiments just described which will not equal to that of the cathode particle in be given here as they will doubtless suggest vacuum tube phenomena. Really, how: ever, themselves to the reader's mind. the b-particles are electrons ejected from Before closing this article it has been radio-active substances at a considerably thought fitting, however, to describe several higher speed than that observed for the experiments with this remarkable little in- cathode particle. strument—the spinthariscope. If the ex- To show the effect of b-rays on photo- perimenter will take the spinthariscope into graphic plates a very simple device suffices. a dark room he will be able to see wonderful The following experiment may be easily flashes of light resembling shooting stars. carried out. An ordinary photographic It is best for the observer to remain for plate is wrapt in black paper; a few metal several minutes in the dark before attempt- objects, such as coins, keys, etc., are then ing his observations, so to allow the eyes to placed upon it and covered with a piece of become accustomed to the darkness. Upon radio-active ore. Any uranium or thorium further observation a pulsating nebula of salt may be used instead. The exposure light surrounded by flashing meteors will should last several days. The action is be seen. This is caused by the fluorescence much slower than X-rays and the results due to the ions from the disintegrating much less clearly defined. A plate with atom striking the zinc and sulfid screen. uranium salts on it is shown in Fip. 1, The spinthariscope clearly shows the con- This lack of definition makes this method stant shower of particles given off by radio- ill-adapted for practical radio-graphy. The active substances without any sensible de- A Small Silica Capsule, Shown in Natural salts of uranium and thorium have been Size, Containing 1,764 Milligrams of Anhy- preciation in their weight or power. found to give off the beta particles which drous Radium Barium Bromid, Having a The spinthariscope may lie used in an- affect the photographic plate. An interest- Radium Element Content of 740 Milligrams. other very interesting and instructive ex- At the Present Market Price of $120 Per ing experiment is to take an incandescent periment. earlier experimenters with Milligram, This Radium Shown in the Dish The gas mantle which contains thorium, and Has a Cash Value of $88,800. (Continued on page 68) — ! —! 36 ELECTRICAL EXPERIMENTER May, 1919 THE CONSTRUCTOR Not 'filOEiiOgraplhi iy TMOMAS REED WISH you knew Gladys Doolittle. No idea I could sue Gladys or her father or been endangered by these instruments ever I don't, either. I've got no grudge somebody and get damages — if the jury since the "Pup first heard His Master's against you. The Doolittles live in the should decide I was less valuable crazy Voice," and you know it. I next wing of my hotel, and as their than the way I was before. If anybody- It's a "Noiseless Phonograph" that's parlor windows face mine I know all wants to buy my claim, I'll make an attrac- needed, and as usual I have to invent it ahout the family, except who they are. tice price on it, for cash "or what have nobody else will waste the time. Some- "Gladys Doolittle," is only one name I call you?" times I get almost discouraged raking her—among others, yes, many others I suppose it isn't really Glad's fault that around after the big inventors and clearing Gladys entertains a young up the poisonous by-prod- man quite frequently. It ucts they leave. Everything isn't the same young man falls on Patsy Bolivar. —I wish it was. She's However, here's your new- "looking 'em over," and phonograph, not only !»- the specimens come on in audible except to the per- a remarkably even proces- sons who want to hear it, sion, one at a time, some but one that you can make way she has it fixt. No yourself with hardly any- fights, or jostling in the trouble. With this and the ante room ; never any nov- prohibition law in opera- elty like that. tion, I feel as tho the Home Her entertainment is a might straighten out and stock sketch, always the survive for several years. same. From 8 to 9, the This machine has be- visitor engages in conver- come possible, in a practi- sation with "Pa" Doolittle cal sense, only lately, thru about what they've both the invention of the Skin- read in the newspaper, derviken transmitter-but- -while Gladys butts in oc- ton, a complete transmit- casionally with remarks on ter in itself; and right here the sock she's trying to I sure won't object if Mr. knit. Thus "Pa" samples Skinder makes one simo- him, and at the same time leon on his part of the the victim makes up his rinktum, because he adver- mind whether he likes this tises in our "Mag." like a better than the hall bed- regular fellow, and will room on the whole. About sell you a single button if 9, he tries to pet the dog you want it. one of these micro-dogs Fig. 1 shows the general it is—and it bites him ; the layout. For the whirling cake hound has to have his table, take one of these sample, too, I suppose. At round shallow tin pans 9:15, "Pa" retires. He's a they use for baking Wash- nervous wreck or some- ington-pie sections — or thing, and needs the sleep ; strata, I guess you'd call if he forgets he needs it, 'em. The Five and Ten '11 Gladys reminds him. Then, have 'em. Take some new scene : she turns off pains to fix it true on the all the bulbs except the spindle. Well Fellow Constructors pink reading-lamp, chases — — Here's the Original "Noiseless" Phonograph. First The spindle runs in holes You'll Need One of Those Transmitter Buttons That's All the Rage Now-a-Days. the knitting off the daven- You Stick a Needle Holder On Said Button, Rig Up a Pie Tin Turn-Table, Hook thru two brass elbows. At port, and trails over and Up a Battery and 'Phone to the Button, and Let 'Er Go! the lower end, to reduce opens up the phonograph. friction, point it off and The "vamping" is about to begin. the instrument she's using in her "labora- have it bear on a piece of glass. So far the performance has been con- tory" operates on the neighbors as well. As the transmitter-button is so much fined to the home, but from this on it in- Phonographs are loud ! all of 'em. The lighter than the ordinary reproducer, the vades the neighborhood, and atrocities come manufacturers took pains to make em so, pressure of the needle on the record will hard and fast. Gladys uses "haunting" out of an absolute misconception. They got be negligible, so you won't need a gover- melodies in her vamping business, and as the idea very early that several or more nor. Your battery motor will run it evenly- the vampees are always different, one people would like to hear 'em at once. enough, and the speed is regulated by your haunter is all she needs at a time. When Why, even now, when they ought to know- rheostat. she first came it was "Memories," but that better, they publish those pictures showing Fig. 2 shows the method of attaching the wore out on her, and ever since then it's the whole family sitting spellbound, mother needle to the front stem of the button. been "Poor Butterfly." Does it haunt? dropping her sewing and Johnny his Mec- Fig. 3 shows the short arm for perpen- Well, look : when Gladys laps her lily finger cano or volume of Browning, and all that. dicular play and method of attachment to and gives that record the initial twirl, and The facts are just the other way. Johnny- the back stud of the button. old "But" soars out into the community delights in the jangled jazz that nobody- Of course it's understood you can con- with his ragtime triplets fluttering around can follow but himself, that makes the nect up as many receivers as there are folks him, we know too well it'll be an hour be- baby cry and the others want to. If Little who want to listen. But say—if any fel- fore the trusty insect will be allowed to Sister starts the well-worn maxixe, and low starts to laugh at you or me for our fold his painted pinions and beat it back falls to dreaming of the slim-waisted "silent phonograph," just remove the gentle to the envelope. Does it haunt? Woof! lounge-lizard she's seen in the movies, little receivers altogether and hitch on a I'm slowly getting crazy from it. Per- mother fidgets and glances at her offspring couple of audion amplifiers from your old it haps you've noticed signs of in my— writ- with apprehension ; and when Big Sister wireless set, then sick "Poor Butterfly" on ings. What's that, somebody says "What puts on the $7.00 "operatic," father picks up that critic, magnified up till he'll think the d'ye mean slowly?" Well, all right, you his paper and stealthily makes for the pretty creature is a night-flying airplane the of it, anyway. I have an kitchen. so it know cause And goes. The Home has with a ton of bombs on its chest. Oh ! Boy : May. 1919 ELECTRICAL EXPERIMENTER 37 Bell- Rami! AtitocJhnna- By T. A. NEELIN present diagram illustrates a 1:30. 2:25. 2:30. 3 25. 3:30 and A p. m. put in place : c" is an insulated copper bell THKsimple home-made attachment for an The accompanying photograph shows the r. ire attached from the rear to the metal ordinary eight-day clock, for the pur- clock as it is in use at the present time. works of the clock, and continuing to the bell, fir of bells are to posi of automatically ringing a hell or rete) n a number ( ommucnoN In worked at the same time, and them working :i relay at certain fuel times, It small A wooden disc bounded by the inner and the battery B was primarily designed for use in a 1 outer circles c' and c was cut from white- wood and finished to about 'g of an inch in thickness. A copper strip of the form c' was then cut and attached to the wood by means of a screw at s' and a coating of shellac to hold it in place in the other parts. A narrow slit s' just wide enough for in- sulation purposes, separates the ends of this strip. The screw s' serves to connect the bare end of an insulated copper wire c' to the copper strip c\ This wire connects to one pole of the battery B as shown. Copper plates of the form c c" c" c' c' c" c"' were next cut and in c', c', c", c" holes just large enough to admit a fi inch screw were bored Corresponding holes were bored in the wood disc. The copper plates were then laid down in shellac and insulated from each other by narrow spaces as shown c" and c* were connected by a wire attached by means of the screws s" and s". and pass- ing behind the wood disc : c" and c" were similarly connected. The dial was then re- moved from the clock and the disc inserted in its place. The hands were next prepared. To the outer extremity of the hour hand was attached a little brush made of fine Diagram of Electrical Circuits and Contacts to of Ringing of copper wire obtained from a Fitted Hands Clock for One or strands More Bells at Different Hours. The Clock Fitted with Automatic Electric piece of "lamp cord" and bound tightly Bell-Ringing Switch. This Arrangement Has about the hand. The hand was then ad- in High School ACTION Given Entire Satisfaction a even- time, and Provides 18 Rings justed in place so as to press the brush for Some be Between 9 A. M. and 4 P. M. ly on the surface it past over. A small From the battery B the current may brass wheel w', say 5/16 of an inch in diam- thought of as travelling thru the wire c' to 3 the copper plate c . soon as the wheel w' high school where it was not thought de- eter rotates freely and smoothly on the pin As current can then sirable to purchase an expensive clock es- which fixes it to a piece of wood as shown. bridges the gap at G the pecially designed for that purpose. The Into the other end of this piece of wood pass to c", thence thru the brush and hour wire clock in question has given entire satisfac- the outer end of the minute hand was in- hand, the works of the clock, thru the ls tion and rings at intervals of about 35 serted. The object of the wood was to in- c completing the circuit and thus ringing minutes with intermissions of three minutes sulate the minute hand from the wheel. The the bell or working the relay. In a few sec- between periods, making some 18 rings be- minute hand was then curved upward in the onds the circuit is broken again at "G" by the on, the bell stops tween 9:27 a. m. and 4 o'clock p. m. An middle to allow the whole to freely pass minute hand moving and attachment constructed according to the over the hour hand while at the same time ringing. The wires shown by the dotted enclosed diagram should cause the bell to the curved minute hand acts as a spring to lines are necessary to get the current from ring at the following times: 8:55, 9, 9:55, hold the wheel firmly against the copper the hour hand to the proper plates so that bell ring at times indicated. 10. 10:55. 11. 11:55 and 12 noon; 1:25, parts beneath. The minute hand was then the may the A "Lead Peimol" Rheostatt The accompanying drawing shows a lead pencil rheostat. The idea is new and very simple at the same time. The lead pencils used are in no way spoiled and can be taken out of the frame and used as if new. pencil) Fig. 2. A, is a pencil (a drawing Setxrtn which has the lead exposed at both ends. B is a screw which is flush with the wood, F, and makes connections with a wire not shown. C is another screw longer than B. D, E, E are the parts of a switch. Fig. 3. It shows the switch side of rheostat. pencil, A, is set between The Split tearing screws B and C. Screw C is screwed down until the both screws make good connections with the exposed lead in the ends of pencil. Connect wires with the screws, connect the wires in the right place on the switch. The Cut mth hocAsow number of pencils used and their length will determine the size of the rheostat. It is best to use good drawing pencils as their re- sistance is higher. Contributed by JONAS GULLBERG. USE YOUR OLD MOTOR Why Not Use Your Old Motor Bearings? BEARINGS. Cut a Slot In the Lining and Close It Up The accompanying sketch illustrates how With a Set Screw. The Lead-Pencil Rheostat. The Pencils. the bearings of small motors can be easily set- Without Rubber Erasers, Are Supported Be- used when badly worn. Remove bearing screw and replace bearing ; tighten Proper Wire tween Wood Screws, as Shown, with hacksaw as shown screw until motor runs without vibrating. Connections Being Made Between the from motor and cut Switch-Points and Screws. in sketch, drill and tap bracket for set- Contributed by HENRY L. BEIMEL. ' 2 38 ELECTRICAL EXPERIMENTER May, 1919 A HEAVY DUTY 110 VOLT, 60 red birch, cut to the dimensions in Fig. 4. THE "TALKING TABLE." CYCLE STEP-DOWN TRANS- The holes marked 1-2-3-4-5-6-7 are for the If the apparatus here described is FORMER. binding posts and 8 for the connecting fastened to the under-side of a dinner table BY RAY SEITZ cord. The other holes are for fastening it will set the table in vibration so that any the transformer to top. fastening With this article I intend to fill the want When l of the experimenter for a good and ef- transformer to top, four pieces /j," gas ficient transformer. pipe l'/z" long, will separate the core at the right Solder The first step is to make the core. From distance from the top. a piece of black sheet iron cut enough Fig. 5 gives the dimensions and shows how to cut the sheet for making a box to fit the transformer. It is made from 24 gage sheet iron, having the corners riveted ~' "' together. ~7n&kU,A-k-J : Short-circuits and heavy overloads will . ., . SJ _ ;. ,;... , not harm this transformer, if not left on for too long a time. This transformer, if ^_j built the way described, will work perfectly and is absolutely noiseless at low load and fig 2 at full load produces a slight hum. It con- sumes about live watts at no load and draws r ' about 250 watts at full load. The sec- G H ondary has six steps of three volts each, O three volts between each terminal. This T transformer is designed to operate on the h- 6 o o o o o standard current of 110 volts 60 cycles. H/V The writer has built several of these trans- formers and they work to perfection under c/ J many different conditions. fig 5 fig 4 A NEW WRINKLE IN ROLLER A 250-Watt Step-Down Transformer for Use BEARINGS. In the Laboratory, in Cautery Work, and Gen- eral Experimental Work. Most machine bearings are made of the Fig. ring-oiling type, that is, the is " bearing sup- strips 5" long 2 wide to a pile \y make plied with a reservoir for oil, into which 3" high and 3]4" " long and V/2 wide to dip one or more rings that run upon the pile 3" high. An Entertaining Wrinkle for the Electrical make a Now build four cores shaft, and thus supply the journal con- "Bug" to Try Out—the Talking Table. The like those shown in Fig. 1, two from the tinually with oil. During the operation Magnet Connects Up with a Microphone and the larger size and two from the of the machine there is a continuous How Battery. small size strips. When you have done this of oil thru the bearing, which not only clamp tightly in a vise and well with wrap keeps the shaft well lubricated, but tends number of persons putting their ears flat three layers of good friction tape. On the to wash away any particles of metal that upon the table, will hear a person talking long legs wind three layers No. 12 C. D. C. may be worn from the rubbing surfaces. over the 'phone, if it is connected up as copper magnet wire, 30 turns to the layer, In a dynamo, it is important that the shown in the accompanying sketch. taking a tap off at each layer. The two legs oil from the bearings should not follow A small piece of sheet brass is cut as will require pounds of wire. 2% Now wrap the shaft and run out on the armature. shown in Fig. 1. A piece of soft iron wire, layers of friction two good tape over this The oil itself is not so injurious, altho such as that used for cores of induction and begin winding the primary which con- it tends to destroy the insulating varnishes, coils and about 6 inches long, is bent at sists of 6 layers No. 22 S. C. C. magnet wire, but it causes an undesirable accumulation one end as indicated at (A) Fig. 1 and 80 turns per layer, using a layer of paper of dust that may greatly impair the in- put thru a hole in the center of the brass between each layer of wire. This winding, sulation. plate ; the other end is bent into the form the primary, will require V/2 pounds of No. The accompanying diagram shows a new of a small hook. Next cut off about 2 22 S. C. C. magnet wire. After you have type of roller bearing, so designed as to inches of a cheap lead pencil and soak it in the both of legs wound wrap again with two run without the use of any lubricants. It water till the lead will come out easily, friction layers of tape and paint the whole is as simple as it is efficient. then glue the pieces of pencil to the wire heavily with shellac and bake in an oven for This bearing consists of an outer hard- just above the hook. Take a piece of cigar- three hours. Now put the four legs together ened-steel casing and an inner hardened- box wood and cut a piece about lfjj inches drill and a hole in each corner in the center so it will fit over to pass a %" bolt A*B*C*D— the leadless pencil on the wire, Fig. 2. 2 tlardened iteel j/eere. and holes to receive the two After the holes are drilled, the binding posts, Fig. 2. Glue Bearing ro// /'-•., next thing to do is to solder the the disc over the pencil on the taps on with short pieces of No. wire near the upper end. The 12 R. C. wire and brought to ^tKkmmmmmimfmmmmmtmtmimttmMm binding posts are then placed their proper binding posts. No. 1 thru the other two holes. The comes from the beginning of pencil is now wound with No. secondary winding, No. 2 from 24 B. & S. silk or cotton cov- first tap, No. 3 from second tap, ered wire, the end of the wire No. 4 from end of winding on being fastened to the two first leg, (end of winding on first posts. A small weight, weighing leg and beginning of winding on about two or three ounces, is second leg are joined together, Spacing or /d/er roll hung on the hook. The appara- and tap 4 also comes from this tus is then screwed to the under joint). No. 5 from first tap on side of the table and connected second leg. No. 6 from second A Bearing You Will Want for Motors and Dynamos. It is Particu - up to a microphone and batten . larly Strong and Runs Without Oil or Other Lubrica tap on second leg, No. 7 from nts. Contributed by end of winding on second leg. WADE ROBINSON. When connecting the ends of the wind- steel sleeve. Between these are placed two ings together care should be taken to see sets of rollers of two different sizes, the that they will help each other along and smaller serving as the spacing or idler CLEANING PAINT BRUSHES. not "buck" each other. By applying the rollers and the larger being the essential For cleaning hard paint brushes make a hand-rule for electro-magnets you can bearing rollers. The relative position of hot solution of lye water ; stand the brush easily figure which ends have to go to- these rollers is shown in the sectional so that just the bristles are in the solution. gether. The primary sections are connected sketch. The idler rollers are so designed For making old corks new. Boil in hot up in series with each other, applying the to run on what may be called a track, and water for one-half hour. hand rule as in the case of the secondary are held loosely in place by two retaining Contributed by AN EXPERIMENTER. and the two remaining ends are spliced to rings. a piece of black extension cord for con- The bearing is suitable for all kinds of necting up to the supply. The hole, 8, in work. When used in connection with line A new thermostatic metal which is re- Fig. 4, is for this piece of extension cord shafting, the outer sleeve fits into a shell, markably sensitive to heat has been in- to go thru, having first bushed it out with held in place in the hanger in the usual vented. The metal may be used in connec- a piece of fiber tube from a 30 amp. manner. tion with an electric thermostat to control cartridge fuse. Contributed by heating systems and to give the alarm in The top is made from a piece of Yi" PETER J. M. CLUTE, B.Sc. case of fire. ; May, 1919 ELECTRICAL EXPERIMENTER 39 A PHOTOGRAPHIC PRINTING BOX. Reversiiraf* RIKeostatt for The inconvenience of the printing frame Small! Motors is entirely done away with in tins electric is built the motor final end the wire is tacked to the lower printing box. In regard to time tlie saving This rheostat under oi base 6 x 8 x '/i inches. On side of the base. Wind the other side in is enormous. The necessary material re- on a wood side of the base, ly* inches from like manner. The lever is a thin piece of quired follows: 1 piece wood 1"/12"/17" each '« carrying two short (base); 2 pieces wood \"/\Z"/\i" (.sides); the ends, cut two grooves inch deep and wood Yi inch wide, 1 inch wide, leaving a space of >/z inch be- binding posts, li B, which serve as sliding 2 pieces wood \"/\2"/\2" (ends) ; 2 pieces wood 1"A>"/17" (top-hinged in the middle) .•"/ j" 1 piece glass (plate) 15! 10! : 4 tmig- Steo lamps; 1 ruby lamp; 5 sockets, and 1 to magnet of motor lamp cord with plug. The ln>x is assembled as shown in the ligure. The sockets are screwed 2" up from the bottom on the ends and are 5' apart. One socket is put in the middle for the ruby lamp. The next step is to wire Pin to 3top the sockets according to the diagram, leav- lever ing enough wire to go over the tup for the automatic switch which now will be taken up. The object of this switch is to turn on the four white lights when the lid is down. To ormotvrt Control ' y It consists of an L-shaped piece of spring cf motor Lever brass or phosphor bronze that is screwed t to the cover and tits into a V-shaped piece Slid/ha 3 of metal when the cover is down tight. A contort piece of wire about 2' long runs over the top to the L-shaped switch. The other side Insulated copper can be wired up from the inside of the box. ~#ire ft* SO The remaining step is to put on the glass Toormotunt plate. The glass should be as heavy as of motor to jfop possible plate glass is the best. There is Pin ; fc /^~ often quite heavy strain on the plate from lever a "~v printing and consequently a light glass is liable to crack. The top of the box is now -2- -1- rabbited out J4" deep and J4" wide from // /glass, \1o1o of motor f- mognef A Handy Reversing Rheostat for Toy Motors. It Controls the Speed In Either Direction ClOSS ^A J and Can De Actuated from a Distance by a String Attached to the Handle. ° ' 3 tween. Take about thirty-five feet of No. contact points, connecting the arc, A A, and 28 insulated copper wire, fasten one end to the coil, D, off of which the insulation hat a binding post under the base as shown been scraped in the path of the slider, B. Top View Cj~'j:> in Fig. 1, and wind it around the base close- The nearer the glue is to this path the ly and evenly, gluing it near the place where better. the sliding contact, B, is to work. The Contributed by OSCAR ROSE. T Dyr&aunioinnietter Electric tachometers have not proven a fastened on a suitable adjustable support. success where accuracy is demanded such The requisites are one solenoid with lamin- as in dynamometer testing work and there- ated soft iron core, one old electric bell Switch fore several revolution counting apparata magnet, a circular saw, a few small gears have made their appearance on the market. and a little work. These latter usually take the form of The small brass drum attached to the operating in has a piece of insulation in the path Q—T\ * : -W solenoid operated clutches saw turn revolution counters. When the fuel- of one of the brushes whose length is suffi- weighing ap- paratus makes ^J contact, the clutch is en- " Circular Brass x/ft1 f/e/ib/e shaft gaged and a so* Amateur Photo Printer Provided with Auto- si teetl> drum button to dynomgmeter matic Switch for Opening and Closing the stop watch started. When Light Circuit When the Lid Is Operated. the weighed quantity of the inside all around, so that the glass will fuel is used up fit in flush with the top. The top is hinged the scale breaks in two places in the middle opening, and contact, the two more places on the end to give no play counter is stopt at all to the cover. It is well to cover and the stop the inside of the top with a piece of cotton watch stops. flannel the size of the glass plate. This Thus an accur- insures that the negative will be in firm ate method of contact with the printing paper. determining It is seen from the wiring diagram that pounds of fuel the ruby lamp is kept burning all the time. per brake 'Jtercuru Ironclad This is to allow for printing masks to be - horse power well solenoid ?djusted. the negative to be arranged, etc. hour is se- This printing box is capable of turning out cured. A Clever Revolution Counter for Use with Dynamometer in Testing. prints at a rapid speed, doing away with the A "seconds Work. It is very simple clumsy printing frame. pendulum" is a in construction and will repay anyone who pretty handy piece of apparatus to have in cient to cover the circular distance of all constructs it. any laboratory. I built such a pendulum so teeth over thirty, so that there will be Contributed by that at every swing the lower end of the thirty movements of the saw or a time MALCOLM MACURDA. pendulum would brush thru a mercury cup (Continued on page 73) 40 ELECTRICAL EXPERIMENTER May, 1919 HOW-TO-MAKE-IT This department will award the following monthly prizes: First Prize. $3.00: Second Prize. $2.00: Third Prize, $1.00. The purpose of this department is to stimulate experimenters towards accomplishing new things with old apparatus or old material, and for the most useful, practical and original idea submitted to the Editors of this department, a monthly series of prizes will be awarded' For the best idea submitted a prize of $3.00 is awarded: for the second best idea a $2.00 prize, and for the third best prize of $1.00. The article need not be very elaborate, and rough sketches are sufficient. We will make the mechanical drawings. Use only one side of sheet Make sketches on separate sheets. FIRST PRIZE, $3.00 SECOND PRIZE, $2.00 THIRD PRIZE, $1.00 A MANUAL TYPE CODE LEARNER. TAKING YOUR OWN "MUG" IN A PROPOSED "BELL SOFTENER." I give below drawing of a "code teacher" GROUP FLASHLIGHTS. When some one comes to the door and which I am contributing to the "How to When taking group photos by flashlight rings the bell, its sudden sound scares Make It" Department. it is often desired that everyone be in the This code teaching instrument can be picture, but as someone must hold the flash- Be//- easily at practically made no cost. A board pan and set it off at the proper moment, this is often impossible. I have a plan, which is explained below, which allows everyone to be in the photo. In the diagram a is push-button held by photographer ; fc is spark coil, the wires from a being connected to the primary side Iron Com of the coil, with set of dry cells in circuit; Baft..A r is one wire, from secondary side of coil, which is taken thru hole in bottom of holder and soldered to c: d is other wire from secondary side of coil which is taken thru So/eno/cf hole in back of holder / and turned down until there is a gap of about one-fourth inch between it and e : the covering should be removed from d for about one inch from end ; e is baking powder can cover which should be securely fastened to holder / as The Sudden Jar On the Nerves Caused by shown is holder made of two pieces of To Make This Simple Code Learner, Cut ; / Ringing the Ordinary Bell Can be Obviated Out the Dot and Dash Characters On by Inserting a Solenoid-Controlled Rheostat Strips of Tin and Embed Them in Seating In Series with the Bell and Battery. Compound. The Buzzer Circuit is Made and Broken Over These Projections. everyone. With this device it starts softly and gets louder gradually. The apparatus (any size to suit the maker) has slits cut used is the same as generally employed into it lengthwise with a knife or saw, as for this purpose with the exception of the indicated. Tin or brass strips are procured, softener, which is a large cylinder wound with a length equal to that of the board. with resistance (R), which is entirely in The dots and dashes are cut out along the circuit at the start, but is varied by the edges of the strips, as in the drawing. slider S. When the key PB is released, They are put in the slots, then connect all the slider is pulled back to the original together with a wire. Then take some wood position (having been pulled down by the about ;4"' ncn square and put it around the magnet M) by the spring SP. edge on the top. Melt some sealing com- CAUTION: Do not have the slider too pound and pour it in the box just made by far from the magnet ; make the cylinder putting the wood strip around the board, to short but large in diameter. Do not use within J-8-inch from the top of the tin. Then ;" too much resistance ; allow enough cur- cut out a piece of tin to make the "pen rent to pass so that the magnet will work. connect it up to a buzzer or telegraph Contributed by sounder and slide the "pen" across the tops ERXEST IXXES and ETHBERT REED. of the tin strips, which makes the dots and dashes at any speed desired. SPARK-LIT INITIALS Contributed by LOUIS C. KING. I here give a description of spark-lit ini- IMPROVED MORTAR AND tials formed from old shoe nails, driven PESTLE. into a block of wood so as to form letters A piece of wood 3-4" x \ />"l x 3" is used When a mortar and pestle are used for Push button for the base, initials one inch high are grinding chemicals dust often gets into the drawn on the base and the shoe nails are eyes, or small particles are driven out of Push the Button and Take Your Own driven into the initials about 1/32" apart, or the mortar and are lost, particularly in the Electric "Mug" with This Unique a little more. The initials are connected case of haTd crystals requiring a consider- Flashlight Scheme. Si c e ~j~ s Cofinec f/ng ^Sf>oc noils wood about six inches wide fastened to- mre " ( gether at right angles and covered on the inside with sheet asbestos, which acts as reflector and protects wood. Holder can be placed on either side of camera, but must be back of camera. HBS9 How It Works.—The operator puts the proper amount of flash powder in the bak- ing powder can cover, in and around the point of wire d. He then arranges his group, using the camera finder for this pur- pose, leaving, however, a place for himself. Spar* a//A, tl The light in the room should be turned low. What Is Prettier Than Spark-Lit Initials leaving only enough to see by. The camera Such as These, Which Can be Lit Up by Even a Small Spark Coil. Make This Simple Cover for Your Mortar and shutter is now opened, the photographer Pestle and Keep Out the Dirt. takes his place in the group, and at the together as shown and wires are connected able force to break them. A simple but proper moment pushes the button. The from the secondary terminals of a spark coil very efficient safeguard consists in making spark between wire d and baking powder to the letters. When the coil is excited, a cover for the mortar from a circle of can cover sets off the powder, after which sparks jump from nail to nail, lighting up cardboard, with a central hole just large the photographer closes the shutter, and the the initials in a very pretty way in the dark enough to admit the pestle as sketch shows. picture has been taken. Contributed bv Contributed by H. T. GRAY. Contributed by GLEN M. ROYSTOX. DE FOREST G. STICKNEY. 3 May. 1919 ELECTRICAL EXPERIMENTER 41 METHOD OF FORMING A SHORT- RADIUS BEND IN CONDUIT. A Low-Reading Volt-Ammeter By Garnet \Y. Shiklky Remove the balance wheel, bearings, and be nearly .3 watt. One watt should pull To make a -hurt radius bend in conduit hair-spring from an old alarm clock. Using the armature or plunger the full distance for a location such as that indicated in composition wall-board or thin wood, make into the coil. A iquare of paper covers 3x3'/2 inches : in. opening Fig. 1, the method to he descrihed can be a box and s deep. For the in the trout anil a (.'la-,* fitted used. Where turns of the usual radius are ease in adjusting, the front should be cut into slots exclude! the durt. Each coil may away as shown, and the front should be be joined to a common post at the top but easily removable. In the center, both hack and front, bore a small hole to receive the bearing screws, which are cup-shaped in the ends. The balance wheel should spin freely when in place. On a thin sheet of soft iron, taken per- haps from an empty tomato can, draw a circle with a radius of one and one-sixteenth inches. Inside this circle cut an armature like the letter S, as shown in the drawing Punch a small hole in the center of this "tin" letter S, and slip on the balance-wheel Above: The Electric Conduit Pipe Should shaft and fasten to it. Push the hair-spring Always Be Neatly Bent and Fitted In Place on the shaft above the wheel. The free Like This. The Bends Must Be Even Curves, Not Kinked Bends. end of the hair-spring is secured to a small post. The spring must of course be ad- justed to the proper tension. A thin pointer made of No. 32 wire is made fast to the balance wheel, letting the end project up thru the slot cut at the top of the instru- ment. A bit of colored paper should be glued to the end of the pointer. Around a stick of wood half inch thick and |Hi wide, wrap a couple of thicknesses of cardboard, gluing carefully. On this long rodius form wind one layer of No. 20 four feet. Conduit Procure an Old Alarm Clock. You Are Then Fasten this with shellac. Over this coil fig 2 Ready to Start Building This "Triple Scale" wind 5 turns of heavier wire, say No. 14. Volt- Ammeter, a Most Useful and Desirable For the voltmeter coil 40 feet of No. 32 Measuring Instrument for the Experimental Laboratory. Above Is Illustrated How Not to Bend Elec- may be used. This makes 200 turns and tric Conduit. Such Pipe Bends Soon Loosen, has a resistance of nearly 7 ohms. dry to a separate and Besides Present a Very Unworkmanlike A post at the bottom. Instru- Appearance. How to Bend Conduit Right Is cell giving 1.5 volts will send over 1/5 ment will work in either horizontal or ver- Explained Herein. ampere thru this coil. 200 x .2 amp. gives tical position. Calibration should be done 40 amp. turns, or 40 feet x .2 amp. equals last. If no standard instruments are at 8 amp. feet. .2 amp. at 1.5 v gives .3 watt. hand, each made, the conduits do not lie close to the dry cell in series adds 1.5 volts. surfaces and present the undesirable ap- When the ammeter coil having 20 turns or For the ammeter scales, two cells in series 4 feet is 2 it will will pearance delineated in Fig. 2. But with this carrying amperes too have send 6 amperes thru 48 feet No. 20: method, bends of the approximate form 40 amp. turns or 8 amp. feet, and will exert one cell will give 3 amperes thru the same the same magnetic pull as the voltmeter wire, and 1 diagrammed in Fig. 1 can be so made that ampere thru 9 feet of No. 32. coil at 1.5 volts. the inner face of the conduit will lie not My "batterj' tester" has been used often more than 1% inches from the faces of the If we wish to measure a little higher during the past year. Tester may be used voltage beam. A sleeve, P, of a larger diameter we may use 140 feet of No. 36 for a moment on much stronger currents copper wire, having a resistance of than than the conduit, C, being bent, is slipt over 60 ohms. examples given. the end of the conduit (Fig. 3) and then Now at 4.5 volts the energy absorbed will Contributed by H. H DAVIS. the short-radius turn can be formed with a hickey, H. The electrician uses what is known as a hickey for bending all small pipe curves. Comwertiinig SinmaM Motor If&Ho The hickey is nothing more or less than a substantial pipe tee fitted with a handle a Dymiasmio of pipe as shown in Fig. 3. The handle is threaded, of course, so as to screw into If your motor is not already mounted ture i rotated, as well as the strength of the fitting firmly. on a base, it would be well to do so for the field magnet. this experiment. On this base mount two Contributed by E. L. DURGEN. binding posts BB. Then disconnect the wires which come from the field coil and connect them to two dry cells, as shown in the sketch. Connect two short wires from the brushes f^s \ to the binding posts BB, the wires being JL r^^O , \ indicated by A A. A switch may be put between the field coil and batteries if de- X Vx^' \ sired. Now belt the motor to any large wheel, D, such as a fly-wheel of a sewing ma- chine. A water motor serves the purpose Conduit very well. being bent When the armature is revolved at a high rate of speed, current will be gen- fj»~~ Iron pipe hichey erated, which will pass thru the wires HH, connected to a small electric bulb, /, storage battery or to another toy motor. c In my case the motor was very small. * // Large diameter only three inches high, designed to run on pipe or conduit two batteries, and when converted into a dynamo it gave sufficient current to burn 1 a out a two and seven-tenths (27) volt bulb, which I had taken from a flash- Fig light. et To Demonstrate the Principle of the Dynamo It must be borne in mind, however, that the Experimenter Will Find it Extremely In- In Bending All Small Conduit Use Is Made of the voltage of a dynamo is controlled by teresting to Drive a Small Toy Motor with a What Electricians Call a "Hickey." This Is Steam Engine, a Water Motor, or Another the size and number of wires with which it Made of a Short Length of Pipe Threaded Motor, and Exciting the Field by a Few Dry Into a Heavy "Tee." i* wound and the speed at which the arma- Cells. A Small Lamp Can be Lighted. A — 42 ZLECTRICAL EXPERIMENTER May, 1919 EDITED BY S. CERNSBACK PRACTICAL CHEMICAL LABORA- use of a vacuum filtering device. To create A SIMPLE GAS GENERATOR. TORY DEVICES. the vacuum, use can be made of the glass Frequently small quantities of gas are de- aspirators which are procurable at a very sired in the chemical laboratory, and no By Thomas W. Benjamin. reasonable price. To use this for filtering, convenient and simple method of genera- is with a cork having two are many instruments and op- the receiver fitted tion can be found. The apparatus described THERE large enough to take the spout erations in chemistry that can be so holes. One, is very simple, yet it serves the purpose ad- of the funnel, the other having a short glass improved as to make them handier or mirably. Fig. 2. to shorten the time required for a given tube inserted. See First, procure two test tubes, one having A wad of absorbent cotton is placed in reaching a funnels the bottom of the funnel and '" short distance up the sides. This is to sup- Tube Tube B' port the filter paper and prevent it breaking i Rodin tube under air pressure. The bent glass tube is ^ connected to the aspirator and when the water flow is started a slight vacuum will exist in the receiver. Any liquid poured {''/ 5homng effect ySJ.CoffOn into the funnel will be filtered at a rapid ofpressure on) rate due to the air pressure forcing it thru. 5iites ofTube iron Dilute Saturated Solution Apparatus : Satu- / sulphide »iS0 - quickly 4 Toospirafor rated solutions of salts can be more made by supporting the salt near the sur- face of the liquid. The idea being that as the salt dissolves the fluid gets heavier and improved sinks to the bottom, being replaced by other 'pipe/is fluid. This circulation is automatic and con- fig. 2 tinues till the saturation point is reached. fleca/ver- rtoie in test tube A little device, easily made of glass, that can be used with all chemicals is shown in Fig.l Fig. 3. The body is made by cutting a two ^/ inch length from a large test tube and bend- Here Are a Home-made Burette-Pipette rig 1 the edges at the cut heating till and a Vacuum-Filter of Simple and Inge- ing in by nious Construction Welcome in Every Labo- soft in a Bunsen flame. A wad of glass In Simplicity This Little Gas Generator Is ratory. Undoubtedly Unrivalled. Two Test-Tubes, a Cork, Some Rubber and Glass Tubing That's All! process. Many of these are in everyday use in large laboratories but the experimenter dimensions approximately §£" x 7" long, hears but little of them. the other approximately y%" x 10" long. A form of burette, or more properly a In the bottom of the smaller test tube file pipette, having several advantages is shown a small hole with a triangular file (Fig. 1), in Fig 1. Instead of the usual form with into this test tube fit a one-hole rubber stop- the stop-cock at the bottom, a plain gradu- per. Fit stopper, with a right angle, connect- ated tube is fitted at the top with a 6-inch ing tube, and straight delivery tube, as in Fig. length of rubber tubing. The valve in this 2, and insert in smaller test tube. The case is made by sliding a short length of smaller tube A, is inserted in the tube B, the glass rod into the rubber tube, locating the flare of tube A prevents it from slipping same midway of its length. The tube is thru to the bottom of tube B. normally kept closed by this rod but a slight In operating: If H2S is to be generated, a pressure on one side of the rubber will stick of FeS, iron sulfid is placed in tube cause the tube to buckle out and form a A. and the cork inserted. Dilute sulfuric channel thru which liquids or air can flow. acid is put into tube B, filling it about two- The device can be filled either by sucking thirds full. When tube A is inserted into the fluid up into the tube with the mouth or tube B, a large volume of gas is produced. This Suggestion to Get Rid of All Obnoxious by immersing it into the fluid with the valve If is clippings Fumes in the Small Laboratory Is Certainly hydrogen wanted, small open and removing after the valve is closed. Meritorious and Shovis What a Little Inge- of iron or iron filings are put into tube A. This valve will give a finer regulation of the nuity Will Attain. usual stop-cock, drop discharge than the a Right angle fc/6e Rubber tube wool is placed in the tube, being held in place by the turned-in edge. The glass rod used to support the device is fastened in place by heating the rod and tube where Cork they are to be joined until soft and then TuOe rf Tube B pressing them together. A cork fitted over the rod will support the device inside a bottle. In use the tube is filled with the salt to be dissolved and placed in the bottle contain- Iron D/.'ute ing the solvent at such a height that the top su/pbide of the tube is just below the surface. Ad- ditional salts may be added from time to time as found necessary. Salt The aspirator mentioned in connection with filtering can be used with advantage when drying or evaporating. In this case Sfro/gfrf (?e//rery the evaporating dish is covered by a funnel " Sloss ivoo/-' Fig 5 fi/t>e the spout of which is connected to the suc- Saturator Is Easily as An Automatic Made tion tube of the aspirator; see Fig. 4. The f/p.S Shown in Above Diagram and May Come in created will off all fumes and Handy. vacuum draw The Gas Generator Ready Assembled tor vapors at a rapid rate. Should the vapor Business. Get the Gas-Mask, Archimedes! at a time or a steady stream being readily be required for further experiment a con- attainable. denser can be connected in the line between and lowered into the dilute acid in B. Re- Vacuum Filter: When filtering thick the funnel and the aspirator to condense the moving tube A stops the generation of gas. fluids the process may be speeded up by the vapor. (Continued on page 87) May, 1919 ELECTRICAL EXPERIMENTER 43 LATEST PATENTS Electric Device (or Raising Sunken Ion occurs. Surrounding the gap Constant Amplitude Vibration A Non-Capsizing Airplane. Ships. between the electrodes, thei Motor. (No. 1,284,373, issued to Platon (1,288,108, intied to Vladimir V. provided a spiral heating coil, and (No l to Leslie R. Lazaridea.) M sser.) the arc-supporting current i McDoi The design of this airplane may In this novel b b< raiting presl across the electrodes at ihe me for the The ih.it be of biplane type. in- huh ken siups, a number of large samp time the heating i ventor provides a triangular form ot Boating members or tanks are util- switched into circuit. wing, both of which are similar in ized, which are provided with iuit* shape and area, the center of the ab!v ^Jectric-motor driven prop* II< n Medical Coil Apparatus. wings being open, so that the aviator (No. 1 ,290,628. issued to e upward as well as sideways <>r.) and downward One of the princi- Can be operated from commercial pal objects of the inventor is to pro- < vide that if < ir flying machine such A '. lighting < aits rhi i s it three windings on the apparatus, one the engi I stop in mid air, primary and two secondaries. One would then become possible for the secondary is connected with sponge airplane to settle to the surface of or other electrodes for applying the the earth in much the same way as current, while the lower secondary a parachute docs. This is accom- coil provides a low voltage current plish! by carefully balancing the en- for operating a small lamp for endo- tire plane, and the car or body on the interior, for the purpose of causing the float to rotate in the Wttter cither in one direction or the other, about its axis. By means of This ingenious motor is made up flexible insulated conductors leading of a rotary member mounted on a from the salvage boat to the float, square shaft, which is actuated or the motors may be properly con- propelled about its axis by an ad- trolled, and current supplied to them justable belt member, which is alter- their operation. The dependent for nately and regularly pulled taut and cables at the bottom of the float are loosened, by virtue of its attach- fast to the sunken vessel, by made ment to an electrical tuning fork in divers or other means. These by the manner here illustrated. cables can be let out or reeled up by causing the float to rotate, and the cables wound up or reeled off A Vacuum Tube Peak Voltmeter. from differentially grooved drums (No. 1,287,161, issued to Richard H. rigidly mounted on the exterior of Wilson.) the float. An improved method for measur- Safety-Chest for Valuables. ing the peak voltage between two (No. 1,291,051, issued to James L. points of an electrical net work, McQuarrie.) and a further object of which is to By means of an ingenious safety measure a direct or alternating chest, a continuous alarm is sounded voltage without the necessity of in the event of any unauthorized constant calibration of the measur- disturbance of the chest. The alarm ing instrument. These results are mechanism is entirely enclosed in a accompli sht by connecting the in- small separate compartment, which put circuit of the thermionic valve may be readily removed, when the between the net -work terminals, is suspended scopic work, etc. The soft iron core which at the center of chest is open, for repair, etc. The across which the voltage is to be adjustable the wings. passing thru the coils is measured, and allowing the result- as to position, by means of a control ing uni -direct ion.'il pulsating cur- knob fitted with rack and pinion at- Spark Plug and Generator tachment. Combined. (No. 1,290,190 issued to Albert B. Adjustable Thermic Telephone. Herrick.) This interesting patent covers a (No. 1,290,114 issued to Pieter de Lange and Robert Aeronut Baron very ingenious gasoline engine ^park van Lynden.) plug and generator combined, which CXJfj is operated by the compression of rent in the output circuit to pass the engine. In other words, this thru a resistance or impedance. device includes an electro-magnetic generator similar in principle to a magneto which is adapted to be au- Reproducer. Sound Recorder and tomatically operated by the com- alarm is actuated by a gravity oper- (No. 1,290,7 1 1 , issued to Manuel ated pendulum member, which is Cameron.) freely movable in response to any Ear In "recording" the sounds on a disturbance of the chest, once it has piece by creating vari- been set and the chest locked. Also photographic film graduations in light to magnetic means are provided for ations and are picked holding the gravity operated pendu- dark, the sound waves up by a microphone, or a battery of lum when it is thus moved by agita- microphones. microphones, tion of the chest, so as to keep the These battery and rheostat, are alarm bell circuit closed continuously. thru a caused to actuate an electromagnet, M. This magnet operates on two Incandescent Arc-Lamp. armatures attached to the pivoted (No. 1,290,930, issued to Philip K. levers shown, to the longer ends of Devers, Jr.) which there are attached light beam In this interesting form of in- shutters, which may enter the beam candescent arc lamp, the arc is of light in the manner apparent. operated between two electrodes of The variations as aforementioned in tungsten or other suitable material, the light and dark graduations are in a gaseous medium of considerable photographed on the film, and corre- pressure. The inventor provides a spond to the voice waves. In "re- new means for starting the arc be- producing" the voice, the film is past before the beam of light, and the variations in light value pass- GosComprtxxa ^ Cylinder Sparkplug An improved form of thermic pression of the gases in the cylinder telephone adapted for certain pur- of an internal combustion engine. poses, or wherever it becomes an In the form shown, the generator object to accurately regulate the in- constitutes but one coil wound on tensity of the sound reproduction by a soft iron core. This is surrounded varying the volume of the sound by a series of strong steel magnets. ttcjvpton* chamber. In this particular arrange- At the base of the generator there ment the sounding chamber is ar- ing thru the film, cause correspond- is a threaded terminal which fits ranged in two parts, so that one may ing variations in a battery and tele- into the spark plug orifice of the tween the electrodes at low potential, be slid over the other,' thus either phone receiver circuit, by virtue of gasoline engine, so that the com- while the electrodes are below a tem- lengthening or shortening the cham- their action on a selenium cell pression can operate therein to perature at which the electron emis- ber. placed behind the film. push against the piston member. 44 ELECTRICAL EXPERIMENTER May, 1919 WITH^AMATEURS Our Amateur Laboratory Contest is open to all readers, whether subscribers or not. The photos are judged for best arrangement and efficiency of the appa- ratus. To increase the interest of this department we make it a rule not to publish photos of apparatus unaccompanied by that of the owner. Dark photo- pre- ferred to light-toned ones. We pay $3.0U each month for the best photos. Address the Editor, "With the Amateurs" Dept. THIS MONTH'S $3.00 PRIZE WINNER—N. NUSHAWG EREWITH are three views of my "Chemical Laboratory." I think it will be needless for me to give a description of the contents of H my laboratory as I had the view so photographed as to cover that part. A brief outline or history of my laboratory I think would not be out of place. The "Lab.*' as you see it in the accompanying views is an accumulation of five years of experimental work. My first laboratory eon sisted of an old wash-stand, of which a part can he seen directly behind "yours truly" in the view in which I am standing. Year by year I added to the aforesaid wash-stand, as my finances would permit, until today I have what I consider a model "Amateur Chemical Laboratory." My laboratory is not only a place which affords me much amusement but is also my "Study Hall'' and my "College of Chemistry" combined in one. I maintain a schedule of study which embraces two hours each evening, including the study of chemistry, electricity, biolog\ and other studies interesting to those contemplating a life of science. Two articles which I would like to call to your attention, noticeable in the general view of my laboratory, are first: the electric furnace constructed from the description found in the April, 1912, issue of the Electrical Experimenter. This furnace will be found on the ledge below my apparatus shelf in the right hand side of the picture. The other article is the hydrogen sulfid generator, which will be observed beside my specimen cage just beneath the window (to the left). I am sending a separate description of this apparatus to the Editor, hoping he will see fit to publish the same in "your magazine"; so keep an eye peeled for it. This laboratory is located in the cellar of my home and is twenty-two feet in length and fourteen feet in width. It is constructed of plaster board and has a four inch air cushion around it on three sides, so as to protect it against any dampness from the cellar. It is heated by a furnace pipe that you will notice running thru the laboratory. It is fitted with electric lights for general illumination and a gas lamp for use in the printing of photos. I have gas and running water at hand. A hood is also among the apparatus; this serves in eliminating all ob- noxious odors. I have been taking the Q Electrical Experimenter since the August issue of 1 15, and have each copy since that time. I find it to best magazine in its field be the and have highly recommended it to my friends, gaining the "E. E." quite a few friends by so doing. I have found the "Experimental Chemistry" course by Albert W. Wilsdon very interesting, having followed and studied each lesson since the first.—N. Nushawg, 534 Arbor Ave., Dayton, Ohio. 45 May. 1919 ELECTRICAL EXPERIMENTER Scieimce aim SI sum 3. Tlhe Specks ami Space By EMERSON EASTERLING 'I'nn with which Apollo 'Then Laplace tOpt off Newton's T was one of those unhitched the old plugs and run cipia' with his Micaniqut Ctleste. clear bright inmmer bad pulled the old glare around thing to be considered wrinkles in other directions when "Naturally, the first ii i h t 1 when the the brow g it as All is the Sun. The lavages recognized moon and stars stood loose with his treatise 'Almagest. about the means of life on our planet (of course out against the black this was way back in li. C. 200, they knew of ii" other; and worslupt it background of the "On astronomy, and more so on astrol as their God, in the same manner as we sky, casting a silvery ogy, the Gypsies were "there', bul to Um do the $, only they openly acknowledged it light upon the taint i .reeks we owe the coining of thl In lite 'we are aware of an attraction the word vonos, or plant landsi ape. We were 'ASTRONOMY', from the effect by it. Only the blind cannot tee ; ami aOVpOV, motoring along a which means LAW general. Now. it has upon everything in highway, and a< the or astroii, which means star or + we get with a lot of the experiments behind us, '1 the sky Ii ii inn out as Star-Law. From the same which means out that we are 93.000,000 stands we have it figured the cynosure of the time, our conversation I .reeks sprung Thales, the man who miles from Old Sol, and that the hot old drifted to astronomy, being of the scien out in the first discoveries of the electrical tific trend, and our company being more or phenomena, and who was so good at the less scientifically inclined. Pointing to the heavenly twinklers that he was termed the moon, Stokes made the remark, "Old girl, Father of Astronomy. It was him and not since Adam quit rubbing his eyes and be- Chrissy Columbus that told the World in came aware that he was a sentient bung general that the globe that we now know as your reflections have permeated space and the S.O0O mile in diameter ball of dirt and we have become familiar with your lunar water (which is not necessarily mud) was highness. Lovers have sworn their LOVE round instead of a flat chunk upon the by you, and coyotes have howled under .boulders of Atlas. It was he who de- your rays. But not until the spectroscope termined when the equinoxes and the sol- shows up and dissects the moon beam, lay- stices were due to arrive, and he knew be- ing its vibratory secrets bare before us, we forehand when the famous eclipse of the were not so sure after all but that you were Sun was to occur—the one that caused the green cheese, as the story book affirmed. Lydians and the Medcs to throw up the "The old time Chinks were the fir^t guj 5 sponge in their famous battle, you've read to finger around and get on to the ways of of the incident in history. Then the sun- the welkin— in fact they looked right thru dial was invented by a Greek, Anaximander. things the welkin and got wise to such as "Getting back to the history of the thing other primary stuff of the eclipses and we see a poor guy gazing up thru a dilapi- It reported great all-around. was that two dated old farmhouse roof—where there was and pro- old timers named Hi Ho who no roof—and thinking. Well, he thought be 'there' on the astronomical fest to so hard that we now still read of the dope failed to inform their boss, the Copernican theory of the universe. He of of the eclipse that came Emperor Cathay, stuck our planet in with the rest of the is further around unannounced, and it whirling globes and fireworks. He got a stated that according to the regulations of hunch from Pythagoras. the country, the men were forced to suffer then came along and modified the the amputation of their heads. "Brahe theory of Copernicus and cut out the 'cycles "Next in order came the Chaldeans, who and epicycles' stuff, and as he was not claimed to be wised up on the aerial phe- housed up in a farmhouse he built a mag- nomena, and who were able to predict nificent observatory. Then came the apt eclipses and so forth. They blew their pupil of Brahe's, Kepler, who compounded horn and left some records that are real pile of laws and stamped his cognomen on amusing and historically instructing, but a history', they started the ball so that we hear from such guys as Thales, Anaximander, Py- "After a while Galileo grew up from the thagoras, Anaxagoras and Eudoxus, Hip- skipping rope and marbles age and invented parchus, Meton and a few choice more the telescope and pendulum. Looking thru astronomers and not from other lines—of the glass instrument he found that Jupiter course we have heard from some of the had a moon—not the kind that showed up birds in other lines, but as a whole they when some of his marbles collided with too were star gazers and dreamers. much force, tho. After he slipt us a hand- "Then we read of the endeavors of the ful of physics and astronomy and the Egyptians, from the like we become aware school at Alexandria, that from the dress- and of Ptolemy and ing room of Life there ~ 46 ELECTRICAL EXPERIMENTER May, 1919 THE ORACLE The "Oracle" 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 published. 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. for each question. If the questions entail considerable 4. If answer is desired by mail, a nominal charge of 25 cents is made a quick the fee before research work oF Intricate calculations a special rate will be charged. Correspondents will be informed as to such questions are answered. REWINDING TELEPHONE while being wound into pies. There should Q. 1. Can you supply data on a 110 volt, MAGNETO. be 24 pies or coils, each % inch thick. This 60 cycle, A. C. step-down transformer for pipe thawing, the secondary giving (993) Walter F. Hawley, Buffalo, N. Y., secondary winding should give 14,176 volts about writes us with 300 turns in the primary; 21,265 volts 12 volts. 42,530 volts A. 1. We give herewith data on the con- Q. 1. How can he rewind a 3 bar tele- on 200 turns in the primary, and struction of a 2 K. transformer suitable phone magneto to produce 10 volts? with 100 turns in the primary in use. Of W. pri- for operation on 110 volt, 60 cycle, A. C. A. 1. This question cannot be answered course, when the normal number of secondary is exactly, excepting on one condition, and mary turns are reduced in order to raise The suited to develop a cur- core rent of about 13 volts and 150 amperes. that is that you would need a magnetomom- the secondary voltage, a suitable iron primary winding of this transformer eter at hand with which to measure pre- The consists of or cisely the strength of the magnetic flux in iiiiiliiuii 13}4 pounds 244 turns of No. 8 maxwells per square inch of pole-face area. B. & S. D. C. C. magnet wire, or 2 No. 11 We can suggest from our experience in D. C. C. wires can be wound side by side connected in parallel. laminated this line, however, that the armature be and The ttlhe ESecforicgJ sheet iron core, one leg of the wound full with No. 17 to 18 B. & S. gage of on which primary is wound, should measure S. C. C. or enameled magnet wire. This E5 17^4 would be suitable for a potential of 8 to 10 inches long by 8?4 inches wide, and have a Electrifying Our Battleships— The cross-section of inches. volts. Of course, the voltage can always { 2J4 X 2?4 battleship be increased by raising the speed, but na- electrically driven U.S. \ The secondary winding for this trans- "New Mexico," by Charles M. Ripley, ! former should comprise 31 turns of No. turally there is a limit to this, as the ma- the Electric Co. chine will not safely stand too high a of General B. & S. gage D. C. C. magnet wire, and will develop a current of about 13 volts and speed. Problems of Telephotography— j 150 amperes. If this is too difficult to wind Written by an authority on the sub- j —Leroy Leishman. on, 2 No. 3 wires may be used or 4 Xo. 6 A. C. SOLENOID. feet J. wires, connecting these wires in parallel. (994) Stanley Dohrzynski, Cuyahoga "My Inventions"—Xo. 5, by Dr. I Falls, Ohio, asks the Oracle Nikola Tcsla, himself. Q. 1. For data on winding a small A. C. In the Wonderland "Tin Can REWINDING DYNAMO. of { solenoid about 3 inches in diameter and Toys"—by George Holmes. (997) A. C. McLellan, La Porte, Ind.: inch iron core. 3]/2 inches long, with a Ye, Photographing Nauen's Radio Sig- Q. 1. I want to know what size wire the electromagnet j A. 1. Unless such an A. C. nals in America— Startling Scien- armature or field or both will have to be A \ is very carefully designed, which would re- tific Achievement. wound with to get 40 volts and as much quire elaborate calculations, and also un- amperage as possible from a as Close-Ups the Newest Scientific dynamo of \ less it is carefully and very exactly built follows Movies—The Role of Electricity and according to these specifications as com- \ Field is 6 pole, now with 20 Science in Photoplays. wound No. will vary con- puted, then the current taken D. C. wire, 1J4 pound to the pole. The How American Electricians Solved siderably from that calculated. Also in the j armature has 28 slots, wound with 28 coils, the Detector" Problem. "Submarine — j case of the solenoid, with a movable core, parallel lap winding, and has 2 brushes at Illustrated. the current will vary from a very high value an angle of 60 degrees from each other. when the core is just entering the coil, down Wireless" That A New "Pocket \ Each coil is wound with 20 turns of No. 20 to a certain minimum value, when the core Actually Works—with photos the of \ D. C. wire. Commutator has 28 bars, diam- into coil. is pushed all the way the Apparatus in Use. eter is 4^4 inches, length 3 inches, and at a only thing can suggest in your The we Rogers Underground Wireless for speed of 2,000 R.P.M. it now generates 105 with several case would be to experiment the Amateur—by H. WinHeld Secor. volts and 9 amperes. The dynamo is shunt solenoid sizes of wire. For the size of you Don't miss this article—It answers all wound, and when wired for 40 volts I want try winding it full have in mind, you might the "Radiobug's" questions. it shunt also. It seems to pull very hard with No. 18 D. C. C. magnet wire. The Improved Capillary Battery — by now without an> load on it at all. weight which such a solenoid could lift Thomas Reed. A. 1. We would advise as follows con- with the core all the way in the coil would cerning the rewinding of your 105 volt, 9 The New Kolster Direct-Reading probably be in the neighborhood of one- ampere dynamo lam- Wave Meter and Decrcmcter. half pound. The iron core must be For 40 volts the field should be rewound inated, solid piece. Choke Coils— to Design and 1 not a How with the same amount of wire, or l ^ Build Them, by Prof. P. E. Austin. pounds per pole of No. 15 B. & S. gage Experimental Mechanics. Lesson should 1 K. W. WIRELESS TRANSFORMER — D. C. C. magnet wire. The armature DATA. 12. Twist Drill Practise, by Samuel be rewound with the same number of coils \ D. Cohen. and in the same fashion or style of wind- (995) J. R. Johnson, McConnelsville, Ohio, writes this department: The Audion—How to build and ex- ing as previously used, but each coil should haust them, with be composed of 7 turns of No. 15 B. & S. Q. 1. Please give data for winding a I Graphs for different wire. 1 K. W. radio step-up transformer. tubes, by C. Murray. gage D. C. C. magnet the armature A. 1. We are pleased to give you herewith You mention that dynamo load data on 1 K. W. close core step-up trans- iiiiu: llllilllllilllliliB seems to turn very hard without any former. on it at the present time. This most likely The laminated sheet iron core should choke coil or impedance must be used in is not due to any electrical reasons, but measure 15 inches long and 8}4 inches wide, series with the primary winding in order to merely mechanical ones. We would sug- and have a cross-section of 2 X 2 inches, control the current, so that the transformer gest that the bearings be carefully inspected; or 4 square inches. The primary winding will not over-heat and burn out the wind- also on some small dynamos fitted with a which should have taps taken off from each ings. number of brushes, the brush friction is layer should comprise 344 turns of No. 10 made too great, and they should be read- spring B. & S. gage D. C. C. magnet wire. The 2 K. W. STEP-DOWN PIPE THAW- justed so as to have just sufficient secondary should comprise about 12 pounds ING TRANSFORMER. tension against the commutator to elim- In cases, of No. 32 D. C. C. magnet wire, thoroly (996) Joel H. M., Carney Point, N. J., inate any undue sparking. some {Continued on page 50) impregnated with paraffin and beeswax inquires : ' Mry. 1919 ELECTRICAL EXPERIMENTER 47 Test Lesson In Draftsmanship Send for this free lesson which explains let us tell you about the Chicago "Tech" method of teaching the Chicago "Tech" Draftsmanship by mail. Positions at big method. The free «X"C4 ;sss5s© salaries are waiting lesson will "°2»o£2:*aaftS now for competent men. show Co^c, Even draftsmen of limited training and you how well experience are snapped up and paid equipped you are to good salaries. If you are dissatisfied follow Draftsmanship. Enroll with your opportunities, learn Drafts- in the course only if you decide that you manship. Chicago "Tech" will train you can take it up to advantage. No cost, in the most practical way in the short- no obligation on you to make this in- est time. Mail the coupon today and vestigation. Send the coupon. $25 n to $100 a Week Draftsmen always command V Oi- good salaries. And now when American industries are to be called up- on to meet vast foreign and increased do- mestic demands, the opportunities are gTeater than ever. This is the time for you to prepare for a better position—a higher salary. Come to the College or Learn At Home Hold you present position while training. Our experts will instruct fl/f you by mail. Only your spare time is required. You are directly under practical draftsmen and engineers. You are taught exactly the work required in the drafting rooms of big concerns. No time put in on un- necessary studies. This means thorough instruction and early graduation. £*^C2>0 Easy Payments The fees for Chicago "Tech" Courses are very moderate—and you can pay on easy terms. And also, you obtain in a few months what it would take several years to acquire by ordinary methods. You can get an early start. You are soon ready to take a paying position and to quickly get back the coat of your course. Then keep on earning more. FREE Instruments Every student of the Chicago "Tech" mail course in Draftsmanship receives this set of instruments, or a cash credit in case he already has a set. These instruments are of the same make and sizes as are used by high salaried experts in drafting rooms of factories, shops, railroads, etc. You use them while learning— then take them right into your practical work. Auto and Gas Engine Course Send the Coupon—Now All about automobile mechanism— its construction, operation and REPAIR— The Booner you are prepared the sooner you will be holding a job that pays a large salary taught by mail. You train directly under the Chicago Tech" automobile ex- and opens the way to advancement. Many executives, general managers and superin- perts. Splendid opportunities open now. Send coupon and get all the facts. tendents began as draftsmen. Learn Ail This in Spare Time Other institutions ask you to pay first— and then to find out later how well qualified Principles of the Automobile, nd how to teat them. Splash you are for this profession. We send you the free lesson first and place you under no obli- Every point made clear about the baai and circulating sysU-mn. Operation in dif- gation at all. Discover your qualifications before you pay anything. Dapm ferent cars explained. DiaarsmH and tables. Cooling ayatems completely illustrated, etc. The coupon __ In pleasure and commercial cars, Batteries. Electrical principles ex- will bringtheTest Caaoline Engine*. All about the plained. Instructive diagrams of wiring and Lesson, free. Al- connections. Coils, condensers, vibrators, different types. A complete coarse in jraa CHICAGO TECHNICAL COLLEGE, etc., so information engine construction, operation and repair. etc. 545 Chicago "Tech" Building, Chicago Power Plants and Transmissions. Ma Kne to Ignition. Principles and about the profes- Application of power by cylinder practical operation of various types and Without obligation to me. please Bend me your FREE Test Lesson and) 4-6-S 12 systems with diagrams. Generation of sion of Drafts- engines Types of clutches, gears, drives, cur- other interesting literature covering the subject indicated below. axles, etc. rent. Field. armature, highand low tension, manship and de- all explained. Complete in every point. Mark X opposite work in which you are especially interested. Carburetors and Fuel Supply tailed facts about Starting and Lighting Systems. * ' ' Architectural Drafting Plan -Reading—Building Systems. All methods demonstrated. All modern methods. Starters—spark, me- Chicago Tech O Fuel values. How to teat. Gasoline and chanical, air. acetylene, electric, battery— methods, the fees, a Machine Drafting Q Plan-Reading— Shop Men air mixtures. Regulation, care and man- shown in detail with diagams and full ex- terms, etc. Mark agement, etc.. Q Electrical Drafting D Estimating etc., etc. planations. Charging. Motor and gener- with X the branch Lubrication and Cooling All ator adjustments, etc., etc. D Structural Drafting Surveying you are interested in D Know How to Find and Fix Troubles — orif indoubt about D Sheet Metal Drafting D Map Drafting Host complete instruction in auto repair work. Equips you for high pay or to start a which course to Q Builders' Course D Autos and Gas Enginaa boaineaa. Big demand for trained repair men .nd men who know how to Inspect cars. take, write a letter This course makes you proficient. Prepares you to take a job as an expert. Not enough stating facts about competent men now available. yourself and asking * Send the coupon and get catalog and all information \JirU»» *V4f LI " Cjl-T our advice which «bout the Course, the small f«« and the easy terms. will be freely given. this All sent on request. Mail coupon now. Mail either the cou- pon or letter today. City 545 Chicago "Tech" Bldg. Chicago Technical College Chicago. HI. College or Home Study? State which. Yon benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 48 ELECTRICAL EXPERIMENTER May, 1919 Thousands of Wonderful Oppor- tunities in the Electrical Field! The Trained Man Is Needed Everywhere By L. L. COOKE, Chief Engineer, Chicago Engineering Works SI NESS conditions throughout "Shall I BL enter the electrical profes- school will guarantee, under bond, to return America and even the world to- sion ?" but "What is the quickest, easi- every cent paid for tuition, if you are not entirely satisfied day are such that there are now est and surest way to become a trained when you receive your truly wonderful Electrician's Certificate granted you as a opportunities for electrical man?" Time was when it graduate of the school. We teach contract- trained men in the electrical field. The took from three to four years to turn ing and electrical drafting along with the electrical business has grown so fast out an accomplished electrician who course and hundreds of our graduates are and now successful contractors. .electricity is being continually ap- could be entrusted with any job that You can take the entire course plied to so many new uses that the came along. Only a few in your years ago it spare time. No interference with demand for trained your electrical men is used to cost thousands of dollars to regular duties. We understand growing just what faster than the supply. make an accomplished electrician, you must know and have devised a really which amount was wonderful way of instruction by mail. We Even on the farm electricity is made up in ex- now have trained thousands of men and will becoming pensive tuition, board, etc.. as well common and thousands of as train you to your complete satisfaction or money lost the farm lighting and power plants have in non-production while course will not cost you one cent. Remember, already been installed. This shows the student was learning. Hundreds that you will not be under the slightest expenses of thousands of dollars except the tuition price. how broadly electricity is applied to- were lost in A splendid Electrical Outfit is given free day, this manner because the student, and suggests something of the sel- to every student and much of the training dom, if ever, is very great demand for hundreds of is a producer while done by actual work with this outfit. studying. You have no car-fare thousands more of trained electricians. This means a tremendous or living expenses as you would have if you loss to the nation, as a minute's re- studied at a "Where will we get the trade-school. You don't have to men," is the flection will readily buy your show. outfit, or pay for question heard on every side. Elec- the maintenance of ex- Correspondence instruction has changed pensive school equipment as you would trical Manufacturers are spending all this. By this method the student wastes elsewhere. The electrical outfit which we thousands of dollars a week advertis- no time on unnecessary branches. He gets give every student includes Electrical Tools, ing exactly the training Instruments, merely for help. Look at the "Help he will use in practical Materials, etc., and is given work and Wanted" columns of any newspaper throughout his entire course he absolutely free. has the direct personal The price of and see for instruction of spe- the course, you can pay in yourself the' demand for cialists in small the branch he has selected. installments if you want to—in other trained men. The salaries paid to words, you can Further, he can do his studying at home, pay as you go along. These young in payments you men with a thorough knowl- his spare time. He does not have to give can take out of your salary which you receive edge of electricity are unbelievable. up his regular job until he has qualified as from your regular em- a Certificated ployment, it not being necessary The size of the Electrician and is ready to to give pay envelopes going this up until enter his new profession. Think of the you are fitted and ready to into the pockets of electrical take a workers thousands of dollars this one great feature good position as a real electrician. every One week reflects the scarcity of men of correspondence instruction has saved excellent feature of the assistance this the Chicago' Engineering to rill these responsible positions. So. country in the past year alone. Works is giving young men to I urge help them succeed is the free not only is the electrical field greatlv every young man with ambition and employment service. The standing of the vacant pluck to grasp the opportunity that now due to the absence of elec- school is so high and the quality of present conditions offer the electrically students trical men enlisted in the war so well known that many firms rely services trained man. Don't hesitate because of age en- tirely upon our graduates of our government, but it will be more or experience. Young men, to fill vacancies boys and old in their greatly men are needed and staffs. We are continually receiv- vacant when war's results are must fill the gaps to ing keep business requests from employers to send them counted, and the need for going. Do your part. Pre- men to till trained Electrical men. We assist pare yourself for a real position by special- our the industrial places of students to good positions our soldiers izing in some branch of electricity. and keep in All you touch with and sailor boys will need is them for years, helping and swell the demand. a few months' practical, snappy in- advising them in every way struction from a competent engineer and possible. Moreover, the I cannot urge all young reconstruction and you will be ready to go after men too strongly some real to readjusting get into the field of electricity. I periods to follow in the money. But do it now. Our boys are re- know turning the vast opportunities for bright men and war's wake are going to increase the filled with ambition, strong and healthy the opportunities have never been after two years' out-door living. better employment of electrical workers be- than they are now and will How can you hope to compete throughout be for the next yond even the ten years. The natural immense re- the reconstruction period without industry needs vou and the spe- will quirements. cial give you a good chance to make a suc- Electricity is yet to do knowledge and advantages training will cess of your life. Write us and let its biggest services to the world give you? us tell after you all about what we can The Chicago do for you. the war. Tho unlimited are its boun- Engineering Works are have ready We just prepared a new book on to help you. A specially designed daries now. electricity and men Electricity and its Opportunities and I who course has been prepared want that will fit you to send you this know its functionary phases in wonderful book—FREE. and op- the shortest possible time to take up the Write me personally telling me just erations will have even extremely interesting what wider scope and profitable work you are doing and what as a Certificated you would like and opportunity for years Electrician. The course is after peace to do. I'll gladly answer your letter myself the result of many years' teaching is declared. of young and give you the benefits men in of my many this vast field. It is intensely prac- years' experience in this field. But what- The tical. It is highly condensed, most vital question for the simplified ever you do, don't neglect the golden up-to-date and complete. oppor- young "man of You can make a tunity now offered today to answer is not splendid live men. Address L L success in this study, and the Cooke, 443 Cass St.. Chicago, 111.—Adv You benefit 6v mentioning the "Electrical Experimenter" when writing — 49 May. 1919 ELECTRICAL EXPERIMENTER BE A CERTIFICATED ^*\ ELECTRICIANS* A Real Position Like This—For You The country needs thousands of trained, Certificated graduate and receive their Certificate, they are ready for Electricians to fill good positions—and at big pay. It's a real position. But still more, at any time you wish you all a matter of knowing how, and I will teach you by can come to our splendidly equipped Electrical Shops for up-to-date, modern instruction* You can learn at home, special training. No other school can give you this. without interfering with your regular work, by my highly successful method of Home Instruction in Practical A Real Opportunity for YOU Electricity. Wishing is never going to make your dreams come true. You've got to study—to learn. A man is worth Prepare NOW and be ready possibly $2 or $3 a day from his neck down—and no is no limit to what he can be worth from in a few month* to earn your more ; but there his neck up. $46 to $100 A WEEK A trained mind is what gets the big pay. It is this training that you need, and I can train you in a few Send for this Book months. Are you ambitious to make a real success then send me the coupon—today. My book, "HOW TO BECOME AN EXPERT ELEC- TRICIAN. " has started thousands of young men on the Electrical Outfit FREE way to splendid success. A new edition of this has just To every student who answers this ad I am giving a Splendid been printed. I want every young man interested in Electrical Outfit of standard size Electrical Tools, Instruments. Furthermore, to every Electrical Electricity to have copv, and will send one, Materials, etc.. absolutely free. a you ABSO- explain Student I give a truly valuable surprise that I cannot LUTELY FREE and PREPAID. Write me today. here. How I Train My Students Free Employment Service receiving requests from employers As Chief Engineer of the Chicago Engineering Works I am continually to send them trained Electrical men. I assist my I exactly of training a to know the kind man needs students to secure good positions. I keep in enable him to get and hold good positions, and to earn touch with them for years, helping and ad- big pay. I have trained hundreds of men who are holding vising them in every possible way. splendid electrical jobs. Write Now—Don't Delay I give each of my students personal attention and a Delay never got you anything. Ac- complete and thorough training. I give him a SPLFN- tion is what counts. Get started— DID FREE, and much of the .^V^Y*' ELECTRICAL OUTFIT and get started now. Write me ^K^j^' ^ training is done by actual work. When my students send me the coupon right NO\V. M^m&* .o» ;-' L. L. COOKE, Chief Engineer CHICAGO ENGINEERING WORKS S? 441 Cass Street Dept.25 Chicago, III. & writing advertisers. You benefit by mentioning the "Electrical Experimenter" when to : " : 50 ELECTRICAL EXPERIMENTER May, 1919 I connected it as shown in the "hook up." » I proceeded as in sending a telegraph mes- THE ORACLE sage and found that a rapid movement of {Continued from page 46) the key produced a stream of what appeared sparks between the neg. ( pole to be — ) about 1/32 of an inch above the solution. also, the armature may rub against the The so-called "sparks" will continue to ap- field poles, and this can be easily ascertained by removing the armature and noting if there are any shiny spots on the field poles or armature core. ELECTRIC ARC TEMPERATURE (998) James G. Peck, Elmira, N. Y., says: Q. 1. What is the temperature of the l electric arc produced between two /2 inch carbons ? A. 1. In regard to data for building an arc light from two Yz inch diameter carbons to give you a temperature of 3,500 degrees Study these microphotographs! Centigrade, any arc, large or small, gives the same temperature roughly speak- A—New ordinary steel needle. about B—Ordinary steel needle after playing ing ; the large arcs using larger carbons one record. Note the tcom point! giving quantity C—New Sonora Semi-Permanent Sil- simply a greater of heat, vered Needle. Note that the parallel but not a higher temperature. The electric sides (which are not tapered) always fit record groove arc will give you the greatest temperature perfectly. First Stage of "Spark Ball" Experiment. D— Sonora Needle after playing one of any ordinary source of heat known. record. No perceptible wear. E—Sonora Needle after playing over The average arc, using y2 inch carbons, pear as long as the copper wire lasts. (It fifty records. Needle has worn down, either cored or solid, consumes about 5 but is in perfect playing condition. melts rapidly). My question is "What are amperes, on 110 volts, and the candle PreserveYour Phonogr aph Records pow- those sparks?" If not sparks, what is it? er is about 1200. A. 1. The experiment which you describe tmi iNrrautttwT o* quality x Appended are some interesting high tem- is nothing new and is well known to those onori perature sources of heat: who have experimented with electrolytic in- CklAH AS * Bill Bunsen burner 1.870 deg. C. terrupters a good deal. This experiment flame Semi-Permanent Silvered Oxy-coal gas 2,000 can be performed not alone with sodium Oxy-hydrogen flame 2,800 chlorid, but with almost every acid. Pro- NEEDLES Oxy-acetylene flame 3,500 viding the current is strong enough, a ball Replace steel needles! Electric arc (furnace) 3,500 of fire will appear at the end of one wire which touches the surface for the following They play SO to 100 times and are RADIO LOOSE COUPLER DESIGN reason used on ALL MAKES of steel : As soon as the point touches the needle records. Unequalled for con- (999) Alvin Harrison, Albert Lea, Minn., liquid which has a more or less high resist- venience, economy, improvement of asks ance, the solution at this point immediately mellowness of tone and the in creasing of life of the records. Q. 1. Several questions on designing starts to boil. At the same time hydrogen Loud—Medium—Soft loose couplers for wireless receiving circuits. gas is evolved, and the electric current set- 30c per card of 5. In Canada 40c A. 1. In standard practice it is usual to ting fire to it explodes this minute quantity Sample FPPF \ Sonora Nctdic will he sent provide both primary and secondary coils of gas, thereby giving rise to a small ex- r " 1- t" FREE on request. Write for it with loading inductances, these inductances plosion. This phenomenon occurs in very being either a separate part of the circuit, ^onora ^Ifonograplf or else combined with the coupler windings ^'alcB Contpann, ]tnc. themselves, preferably the latter. GEORGE E. BBIGHTSON, President The primary as well as the secondary 279 Broadway. Dept. G., New York circuits are, in the most efficient design of Toronto: Ryrie Building coupler, made so as to form a continuous CAUTION! Beware ol similarly con- structed needles of Inferior quality coil capable of being tuned to the highest wave length which it is desired to receive. Any other form of loading inductance which " '/ is separate from the windings of the coupler Close up of a So/ution only form a source of loss, for it requires a certain amount of energy (PR) to excite Pont Grope for Words Second and Third Stages of "Spark Ball" ^ this separate loading inductance, and, as it Experiment. The Theory of Its Action Is does not form a part of the main coupler Very Interesting. We are all trying to SELL some- thing— it may be brains, or winding, and is not useful in producing a automobiles, or soap—^but words rapid succession, part of the common electromagnetic field and the explosions take are the universal medium of ex- place change. LEARN TO USE THEM which transfers the energy from the pri- several thousand times per. second. CORRECTLY — PROFITABLY, Mr. H. Gernsback some years ago obtained \^H ^^F Get a command of English! mary to the secondary circuit, as you will Spend a rew minutes daily with quite large "fire balls" of this sort by using ^^^^^^^^^^" see, in any event then it must be a source of Grenville Klels-er's Mail Course, a fine carbon pencil as electrode. _ Practical English and Mental Efficiency. It will unrecoverable loss. one surely teach you how to We would refer you to a very good article Use Good English — and Win on "Building a 20,000-meter Undamped Re- 200 WATT TRANSFORMER DATA. Enlarge your Stock of Words—Use the Right ceiving Set," by William Burnett, Jr., page Word in the Right Place— Write Compelling (1001) James Dicks, Delhi, La., inquires 258, August, 1917, issue, also Business Correspondence, Stories, Advertise- Q. 1. Please give me data on 200 watt — "The Design of Large Radio Receiving ments, Speeches Become an Engaging Con- step-up wireless transformer for operation versationalist — Enter Good Society, etc. Transformers," by Chas. S. Ballantine, Ra- Ask for free particulars today. on 110 volts, 60 cycles. them call, dio Engineer, page 732, February, 1917, We send by mail. No agent will A. 1. The laminated sheet iron core for FUNK & WAGNALLS COMPANY, Depl. 267, issue. NEW YORK, N. Y. this transformer should measure, for a 200 "The Calculation and Measurement of In- watt transformer, Vi l inches long by b l ductance," by H. Winfield Secor and Sam- /z /z inches wide and 1 x i inch in cross-section. uel Cohen, parts 1, 2 and 3, which appeared The primary winding, placed on one of the in the March, April and September, 1917, is- Rider Agents Wanted long legs, should comprise 660 turns Every where to ride ** and exhibit^^'' *" —3C No. the new Ranger'Motorblke"com- 15 B. & S. gage D. C. C. magnet wire. Be- pletely equipped with electric light and horn, carrier, stand, tool tank, PECULIAR SPARK BALLS. fore winding on the primary coil, the iron coaster-brake, mud guards and (1000) R. O., San Antonio, core leg should be insulated with four lay- enti-skid ti res. Choice of 44 other J. Texas, •tyles, colors and sizes in the fa- writes: ers of oiled linen or Empire cloth. mous 'Ranger" line of bicycles. DELIVERED FREE on approval Q. 1. I am a reader of the Electrical The secondary winding should comprise and 30 DAYS TRIAL. Send for big Experimenter and desire some information 17 pies or sections, each J4 ' ncn thick, with free catalog: and particulars of our Factory- direct-to-Rider marvelous regarding an experiment performed in my paraffin paper discs between them when offers and terms. assembled. The size of the secondary wire TIDCC Lamps, Horns, Wheels, "Lab" some time ago which I am at a loss I into Sundries, and parts for to know "the why and wherefore" of. should be No. 34 B. & S. gage D. C. C. and all bicycles—at half usual prices. SEND NO MONEY bat tell us Thus: I made a solution of Sodium Chlorid 3.7 pounds of secondary wire are required. exactly what you need. Do not buy and water, in a small beaker. sketch.) There should be about 35,000 turns in the get our prices, terms and the big FREE catalog. (See M PAQ CYCLE COMPANY Using a current of 110 volts and a small secondary, and the secondary voltage with Dept. D107 CHICAGO telegraph key to open and close the circuit, {Continued on page 52) You benefit by mentioning the "Electrical Experimenter'' when writing to advertisers. ELECTRICAL EXPERIMENTER 51 Hour Would You Train 50,000 Employees? t Thin of Western Union's ^ an ar- HOW it Was As WESTERN UNION v _^.^ _^ myof50,000men _ found that there were no mmmK|P ^MFOblfimWB#1^111 and women, dif- SOlVfifl courses covering completely ^ fering greatly in w * ^^" and thoroughly the highly ability, adaptability and previous training — specialized telegraph business, it had special remember that all of them were self-supporting texts written by its own experts, who thus be- wage-earners, who could not afford to let any- came the personal instructors of its employes. thing interfere with their regular occupations — consider After careful inquiry, the Company decided that it was their employer's desire to make intensive train- 6 that the correspondence instruction method ing practical for all, without lessening their present effi- would give all employes an equal opportunity, while its ciency—and you have some idea of the complex employe- flexibility would meet any individual needs and circum- training problem that confronted the WESTERN UNION stances. And finally WESTERN UNION arranged to loan when it undertook to make it possible for any of its 50,000 the price of the Course to deserving employes who might employes to acquire a higher degree of efficiency in be unable to meet even the moderate fee asked for training. their work. The actual conduct of courses and instruction was entrusted to the American v School of Correspondence, Chicago, whose Educational Charter and 22 years' I successful experience eminently fitted it to carry out WESTERN UNION'S V plans to make special training possible to any of its 50,000 employes. Don t Dod£e Promotion Whatever occupation you would prefer to follow you can't dodge the fact that you're dodging promotion — dodging the job ahead, with its guarantee of better pay — so long as you refuse to train yourself thoroughly for the work you want to do. The man or woman with training is bound to succeed—for trained workers are the scarc- est commodity in industry. A glance ac the "Help Wanted" columns of your daily — MERICAN SCHOOL paper a question OF CORRESPONDENCE put to your boss — Wi\\ quickly prove this. The Ameri- A can School can properly develop your natural ability Dept.W7445 CHICAGO, U. S. A. —make you a thoroughly skilled worker. A small part I of your spare time—some of the hours you now waste— Please send me booklet and tell me how invested in systematic study will soon fit you for the I can fit myself for the position marked X: | Western Union Courses Steam Engineer position, and pay, you want. Telephone Engineer Lawyer I ....Draftsman ana DeBig-ner BUfffaen Manager Automobile Engineer Cert. Public Accountant Automobile Repairman Accountant and Auditor Airplane Mechanic Bookkeeper High School Graduate Stenographer i Fire Insurance Expert Gun*! Education Course Make This Test Sanitary Engineer Com. School Branches Heating and Ventilating- Electrical Engineer We will train you on a make-good basis— allow you to test out the prac- Engineer Electric Light and i'owrr Master Plumber Superintendent tical value of any Course by covering the first ten textbooks without Civil Engineer Hydroelectric Engineer Structural Engineer Wireless Operator risking one cent This means that if you're not satisfied with your Mechanical Engineer Architect progress — if you find you're not getting money-earning training from .Shop Superintendent Building Contractor the course — we'll refund every cent you've paid us. Full satisfaction P. or your money back is the only basis on which we accept students. If the fairness of this offer appeals to you—as it has to thousands —check B and mail the Coupon for Free Bulletin. You assume no obligation. ^I^^S330S^!SS22S1^S You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. — : 52 ELECTRICAL EXPERIMENTER May, 1919 laminated sheet iron core of the shape in- dicated in the diagram is built up, and it Tires at Wholesale THE ORACLE may be riveted at several points. It should (Continued from page have a width equal to the approximate Save 1/3 Tire 50) Your Cost length of the armature, and also a pole- Tires Tubes "Armor" face curvature as nearly like that of the 30 x 3 $13.60 $2.90 $3.00 all primary turns in use is 5,890. The sec- armature core as possible. The winding on 30x3}4 17.00 3.45 3.60 ondary voltage is increased in proportion as this transformer may, for a small size de- 32x3% 19.65 3.60 3.60 the number of primary turns in circuit at vice to be used in testing out small magneto Other sizes quoted on request. any time are decreased. The secondary leg or auto lighting dynamo armatures, be com- Order these 5.000 mile Beacon"Rib-Skid" of the core should be well insulated with posed of about 75 turns of No. 14 B. & S. Tires, Red Tubes and 'Inside Armor" 10 layers of oiled linen before placing the insulated magnet wire. at above prices on money-back approval, or write at once for fall description and our pies in place. A very satisfactory and simple test for plan of selling First Grade, Fully Guar- short-circuited as well as open-circuited anteed Tires, etc., direct-to-you. at whole- POINT OF D. C. DYNA- armature coils can be carried out by con- sale prices. Give size of tires and name of NEUTRAL car. Address MO AND A. C. MOTOR necting a buzzer across the brushes, and SPEED CHANGES. thus testing from bar to bar with a 75 ohm MODERN TIRE CO., 659 7th Street, RACINE, WIS (1002) R. G. LeTourneau, Stockton, Cal., telephone receiver. If a coil is short-cir- asks the Oracle cuited or partially short-circuited, then no Q. 1. Several questions concerning the sound or a weak sound will be heard in the shifting of the neutral point on a D. C. telephone receiver. It has been found that Pocket Tool Chest generator and speed changes of induction this test will give better and more accurate Strong Knife Wire Pliers motors. Leather Punch Hoof Hook 9 Tools in 1 Sicrdging Atcl Wire Cutter A. 1. The neutral point on the commu- Screw Driver Screio Bit Alligator Wrench tator of the D. C. generator changes at least To AC Each a strong, practical slightly with changes in speed of the arma- AC. Testing tool. As easily carried as Fhcan Transformer a 3-b]ade knife, and has _•*" ture as you mention, unless the machine no more parts. Length. 4 Wunderknire has one of the following precautions taken in. Fliers and wire cut- ters are drop-forged tool in its design : The machine might have a steel — cut barbed fence wire as easily as 8-inch very powerful field, which would cause a pliers. Blade is tempered very even and rigid distribution of the flux cutlers' steel. Each tool Imo core works independently. Once used, at the pole tips ; the machine might be pro- always carried by Electricians, Rail- way Men. Motorists. Mechanics, Horsemen, vided with interpoles, such as provided on Sportsmen. any one of the leading machines on the Bent pitstpaid in V. S. for $1.75 (add 5c if insured). Highest quality construction, fully guaranteed. market at the present time, which tends to 87 Ba ; B ' dg - preserve an even distribution of the field Elican Specialty Co. ?,', VS^is ,i flux, and thus to preserve a practically fixt neutral point, thus obviating the necessity for shifting the brushes, even on over- Big Profits forYou loads of 50 per cent. Or again the machine might be provided with variable air gaps in HB Battery Charging . between the field pole tips and the armature, Start now to build big battery business. Oppor- such as in the Stow design, where all of tunities best this season—more old cars driven the field poles are geared together by means new Fords with storage batteries. HB users are easily clearing of worms and gear rods to a common hand- $100 to $200 Extra Profit Every wheel on the top of the machine, which Month | Somo even more. Get In the came! This HB 7- enables the field poles to be advanced toward Bartery Charter recharges 1 to 7 aut<> batteries at once. Current cost 12c to 15c per battery. or receded from the armature and the air- Motorist pays 75c to $1.50. Figure your profits. Noelectrical or mechanical experience required to gap flux distribution varied. operate. No expensive renewals or adjustments. Home- Made A.C. Tester for Short-Circuited ffOC Puts Thia Money-Maker in Your You are correct in assuming that several Armature Coils. The Materials Required to V^O Garage on Money-Back Guarantee different speeds can be obtained from an Build It Are Available About Any Shop. Balance in 9 monthly payments of $20 Its Action Is Simple, Yet Positive. each. Earnings easily pay for machine. A. C. motor by changing the groupings of Pin your $25 initial piyment check to this ed and send today for trial order. Yon the field poles, i.e., by changing the number run no risk under HB Absolute Money- Back Guarantee. Don'tdelay. Getbusyl of poles, such as by causing the field to pro- is case Get those profits! results in a minimum of time, than the HOBART BROS. CO., Box5E,Troy,< duce 4 poles, 6 poles, 8 poles, and so on. where the Wheatstone bridge is used. Open- Successful manufacturers since 1S9S This system is adopted in some of the lead- circuited coils will manifest their presence ing A. C. motors now on the market. You when the proper bars are bridged a very POPULARITY FOLLOWS THEf by will find data on this subject by referring loud noise in the receiver. It is common UKULELE, * J to books on A. C. machinery. practice in many shops to use this test in ITyou play quaint, dreamy Hawaiian music l connection with the 110 volt, 60 cycle A. C. or latest songs on the Ukulele you wi|1 be L*4p wanted everywhere. We teach by mail 20 /*F^\ A. C. TEST FOR "SHORTED" ARMA- lighting current, the necessary current being simple lessons: give you free a genuint- I Hawaiian Ukulele, music, ev-rything— .* TURE COILS. past thru the armature in series with a 110 r noextras. Ask us to send the story «~ ) j of Hawaiian music. You will love it. • *^_*i (1003) Earl E. Teater, Wheeling, West volt lamp. obligation—absolutely free. ***j No ^ j Ya., writes the Oracle : If you have a good voltmeter on hand or The Hawaiian Institute of Music Q. 1. For data on a simple A. C. testing posibly an ammeter without the shunt on it, 1-100 Broadway, Suite 1105,NewYork scheme for short-circuited armature coils. you can also make tests quickly for open or BUILD A $ioo A. 1. Herewith we describe an A. C. short-circuited coils or grounds by the bar- PHONOGRAPH testing device for determining whether to-bar test, passing direct current thru the Assemble your own Phonograph armature coils are short-circuited or not and brush points on the commutator. For this Do it vourself easily. Have the finest machine. which is used in repair shop work. The work the armature is usually mounted in a We Astounding saving. small transformer has a single winding on testing cradle, comprising a wooden frame give you the phonograph secrets. Complete instruo- it, which is excited with alternating cur- and one upright which carries a pair of liuns 10 cents. rent suitably controlled by connecting it in adjustable copper or other brushes which ELECTRO MECHANICAL PARTS CO. series with a lamp bank or choke coil, etc. will transmit the testing current to dia- 160 N. Wells St. CHICAGO Using this transformer primary, as it may metrically opposite points on the commuta- QUICKLY LEARNED be called, and holding it in contact with the tor, for the two-pole armature, or four LANGUAGES armature, in successive positions, as the points ninety degrees apart for a four-pole -CfN - ALL PHONOCRAPHi 'Like learning a tune—and as easy." Our Disc Records armature is turned from coil to coil, there armature. In any case where the telephone repeat the correct accent and pronunciation until you know it. Familv and friends enjoy language study by thf is set up thru the armature core a magnetic receiver and A. C. or buzzer method are LANGUAGE-PHONE METHOD flux, which induces a current in the arma- used, or the voltmeter method, the criterion _ And Rosenthal's Practical Uneuistry War has created unlimited opportunities for ture windings. If one of the coils happens of the tests for a perfect armature is to those who know languages. Prepare now to better your position or increase your business. to be short-circuited, as becomes apparent, obtain a similar or very closely similar de- Used and recommended by educators in leading ,-,.11..,— Write i-.r t. — klrt ami Fr-- Trinl Offer. this current will heat up the coil. Also by gree of sound in the receiver for each coil, THE LANGUAGE PHONE METHOO 931 Putnam Building. 2 W. 45th 5t. N. Y. turning the armature a complete revolution or an equivalent similarity in the voltmeter and holding a small piece of iron against it, readings for every coil on the armature. If Built for the Owner >. $990 00 the coils being tested for short-circuits will any appreciable difference is noted in the be easily located, as the piece of iron held meter readings or in the telephone, then the Simple, near the coil will vibrate, due to the result- connections of the commutator, and also sturdy construction. ant magnetic field set up by this coil and the the leads of the coils should be carefully Low cost of up-keep and operation. Can- current passing thru it. The transformer examined. Sometimes a high reading will tilever springs in rear. device should not be put in position nor result from a poorly soldered lead con- Comfortable E-Z riding Immediate deliveries. Fifth suceeas- removed while current is flowing thru the nection to the commutator bar, which on a rifmlpfcLicalcrS WnntAfl Increased output. Liberal WantcO f u ] year. newspaper advertising in dealers' territory. Wonderful opportunities. magnetizing coil of course. superficial examination may appear to be a Write or Wire NOW. job. THE SENECA MOTORCAR CO., 45 Seneca Factory, F0STORIA, OHIO To make this testing transformer, a first-class soldering You benefit by mentioning the "Electrical Experimenter" when writing to ad-eertisers. — — — . M ay. 1919 ELECTRICAL EXPERIMENTER 53 AtDawn theAnswer 1 Now Own a FlashedcmMer K5.000 Homo concentrate. The THERE are How a young man jumped from $30 a truth is, will only a few week to $50,000 a year. His remarkable $50,000 jobs- power will enable success h< i attributes to the way he uses yet of all the men in them to do both. his will. "What I've done, I believe any- the country it is dif- The man who one can do," he says. ficult to find enough can use his will only to fill the few big can not jobs available. There are plenty of men for wrong with me. Along concentrate and the $25-a-week positions—but the thousand- towards dawn the remember, but dollar-a-week openings "go begging." How answer flashed on me can make use of this young man trained himseif for earn- and I resolved to these two faculties. And I want to —And Live In Luxury ings of $50,000 a year is one of the most make an experiment. leave this one word with you—no interesting chapters in the annals of even I decided to cultivate knowledge, no plan, no idea is worth making. This is the will power, believing that if I did this a penny unless it is used—and it cannot be present-day fortune my !" story told me, almost word for word, by I would not hesitate about making decisions used unle-? some one's power of will docs it the young man who did it. —that when I had an idea I would have "Three short years ago I was $5,000 'in sufficient confidence in myself to 'put it PROF. Haddock's miles arm exercises in the hole' and earning S30 a week. I had over'—that I would not be afraid of myself — will training have been placed in book a wife and two children to support, and I or of things or of others. I felt that if I form, and 1 have been authorized by the used to worry myself sick about the future. could smash my ideas across I would soon publishers to say that any reader who cares "Today it seems like a dream—all my make my presence felt. I knew that here- — to examine his startling book on will power troubles are over. I am worth $200,000— tofore I had always begged for succe.-s may do so without sending any money in enough to keep me and my family in com- had always stood, hat in hand, depending advance. In other words, if after a week's fort for the rest of our lives. I own two on others to give me the things I desired. reading you do not feel that "Power of automobiles. My children go to private In short, I was controlled by the will of Will " is worth S3, the sum asked, return it schools. I have just purchased, for cash, others. Henceforth, I determined to have and you will owe nothing. a $25,000 home. I go hunting, fishing, a strong will of my own to demand and When you receive your copy for examina- motoring, traveling, whenever I care to. command what I wanted. tion I suggest that you first read the articles on: The law of great thinking; How to de- " T ET me say in all sincerity that what I "T 1 7ITH this new purpose in mind, I ap- velop analytical power; How to guard against *—; have done I believe any one can do. VV plied myseif to finding out something errors in thought; How to drive from the I am only an average man—not 'brilliant' more about will power, and in my inves- mind unwholesome thoughts; How to de- have never gone to college—my education tigation I encountered the works of Profes- velop fearlessness; How to use the mind in is limited. I know at least a hundred men sor Frank Channing Haddock. To my sickness; How to acquire a dominating per- who know more than I, who are better edu- amazement and delight, I discovered that sonality. cated and better informed—and their earn- this eminent scientist, whose name ranks It is interesting to note that among the 225,000 ings probably average less than $50 weekly with James, Bergson and Royce, had com- owners who have read, used and praised "Power of Will" art- such prominent men as Judge Ben income is over $1,000 weekly. I thorough and constructive while my pleted the most P. Lindscy; Supreme Court Justice Parker; Wu mention this to show that earning capacity study of will power ever made. I was Ting Fang, ex-U. S. Chinese Ambas McKelvie of is not governed by the extent of a man's astonished to read his statement, 'The will is Nebraska; Assistant Postmaster- General Britt; General Manager Christea to encourage those who have not just as susceptible of development as education— the Wells Fare.,, Expr St. F.lmo Lewis; had the advantage of a comprehensive educa- muscles of the body !' My question was Senator Arthur Capper, ot' Kansas, and thousands of others. tion. answered! Eagerly I read further— how Dr As a first step in will training. I would suggest "What, then, is the secret of my success? Haddock had devoted twenty years to this Immediate action in this matter before you. It is Let me tell you how it came about. study—how he had so completely mastered iii»i ei en necessary to write a letter, Dae the blank form if addressing it "One day, about three years ago, some- it that he was actually able to set down the below, you prefer, to the Pel- ton Publishing Company. 80-J WlIcoX Meri- thing happened that woke me up to what very exercises by which anyone could de- Block, 'leii. Conn., and the book will come by return ni.nl was wrong with me. It was necessary for velop the will, making it a bigger, stronger This one act may mean the turning point ol your me to make a decision on a matter which force each day, simply through an easy, pro- life as it has meant to me and to so many others. was of little consequence. I knew in my gressive course of training. heart what was the right thing to do, but "It is almost needless to say that I at Pelton Publishing Company, something held me back. I said one thing, once began to practice the exercises formu- 30-J Wilcox Block, Meriden. Conn. then another; I decided one way, then an- lated by Dr. Haddock, and I need not re- I win examine copy of "Power of will" at your rial I other. I couldn't for the life of me make count the extraordinary results that I ob- agree to remit $3 or rematl the book In I the decision I knew was right. tained almost from the first day. You Name . "I lay awake most of that night think- already know the success that my developed ing it of will about the matter—not because was power has made for me. address of any great importance in itself, but be- "People sometimes worry because they cause I was beginning to discover what was cannot remember or because they cannot You benefit by mentioning the "Electrical Experimenter" zehen writing to adrcrtisei i. ! 54 ELECTRICAL EXPERIMENTER May, 1919 Popular Astiroiniofiniy J^M en Wanted for Airplane (Continued f rom page 25) ured with considerable accuracy and is along its longest axis, while globular star INDUSTRY known to be four and a third light years. clusters distributed above and below its Tho there may be a few faint stars or non- central plane have been found to be at dis- Wonderful opportunities luminous stars nearer to us than Alpha tances from it ranging from ten thousand ——great scope for advance* Centauri, and there is, in fact, one incon- to two hundred thousand light years. This tnent — and big pay await you in the airplane spicuous star known to be slightly nearer, entire organized system is our sidereal uni- industry. This does not mean actual flying, but verse. beyond is unexplored. in any and all of the various branches of the in- the distinction of being the nearest of the Space The dustry. It is the coming profession—the future brighter stars has long been held by Alpha globular star clusters are the most distant means of transportation. U. S. Mail is already our sun continues his celestial objects so far discovered. The being carried by airplanes. Factories are springing up Centauri. As own everywhere and trained men are in big demand. journey thru the universe the two stars spiral nebulae may be entirely within the You can get into this (our sun is a star just like Alpha Centauri) limits of this system or future determina- Ooenini*! in profession HiL^ B w while it is will finally draw away from each other tions of the distances of the fainter spirals flany UranCneS still in its infancy as a mechanic, engineer, repairman, instructor, in- after many ages have past and some may extend the limits set by the globular spector, builder, contractor, salesman or pro- other sun of space will be our nearest star. clusters to include spirals found to be still fessional aviator. minute The you understand distances that separate the stars from more distant. the science and mechanics of The aviation you can step into a each other probably average as great as We can conceive the possibility that our high-salaried position. the distance from the sun to Alpha Cen- sidereal universe, vast as it is known to be, tauri. Within a sphere whose center is at may be but a unit in some still greater or- the earth and whose radius is five parsecs, ganization and that other similar systems We Guaranteed or about sixteen light years, there are only lie beyond the reach of existing telescopes about twenty known stars. There is there- at unimaginable distances of a higher order. fore small chance of collision among bodies The mind of man is overwhelmed by the that are so small in proportion to the tre- thought of sidereal systems as vast as our We absolutely and unre- ^V»?^3h««£te' mendous intervals of space that separate own lying far beyond our ken. Whether servedly guarantee that or not such external systems our Home Training Course them from each other. There is ample do exist and I will enable you to qualify for a good position as room for the individual stars to pursue are with our own sidereal system units in soon as you graduate. The Course itself has their journeys thru without interfer- some still vaster creation we cannot know. I space I been written by noted aeronautical engineers, and covers the entire fundamentals of practical ing with each other's motion so long as they aeronautics. Every lesson is written and illus- are as widely scattered as they appear to trated so clearly that you cannot fail to under- be in this portion of the universe. That 1 stand it. But see for yourself. Take ten les- its sons. Then if you are not satisfied you are not our own sun has continued journey thru out one cent. We guarantee satisfaction. the universe for hundreds millions [ some of of years without any catastrophe such as Prepare Now for a would result from closely approaching or Bis colliding with another sun of space shows Future on how grand a scale our sidereal system Only by specialized instruction can you expect to succeed in aviation or in any line of business. is fashioned. ! Training alone will fit you for a big job— and Stars that are ten, fifty or even one hun- NOW is the time to begin. Check and mail the coupon for Big Free Bulletin and Money- dred light years from the earth are our i Back Guarantee. near neighbors in space. They are the stars that show a slight displacement in the AMERICAN SCHOOL heavens or measurable parallax viewed OF CORRESPONDENCE from opposite sides of the earth's orbit. - Dept. F 744S CHICAGO. 0. S. A. There are probably a thousand stars among the hundreds of millions of ror TRAINING THE KEY TO SUCCESS stars within reach of the greatest telescopes whose dis- J '- Please send Free Bulletin and W /\JtT! tances have been determined in light years explain how I can qualify for r^UU the position checked. by direct measurement of their displacement High School Graduate .....Lawyer in the heavens resulting from the change of ..... Electrical Engineer —Business Manager position of the earth in its orbit. The most ...Xertified Pub. Accountant Elec.Light&PowerSupt. distant of the stars are apparently immov- Hydroelectric Engineer , .-.Accountant and Auditor ....Telephone Engineer ..-Bookkeeper able in the heavens showing neither the Telegraph Engineer ..-Stenographer effect of the sun's motion or their own ...-Wireless Operator ,._Fire Insurance Expert .....Architect ..-.Sanitary Engineer motion thru space. Methods for ascertain- Building Contractor —Master Plumber ing the distances of many far remote stars Civil Engineer ..-Heating & Vent. Engineer Structural Engineer ..—Automobile Engineer and star-clusters have been devised, how- Mechanical Engineer .. Automobile Repairman ever, and some comparatively recent inves- Shop Superintendent ..—Airplane Mechanic tigations yielded Steam Engineer ...-General Education Course have determinations of the ..—Draftsman and Designer ...-Common School Branches distances of these objects indicating that the diameter of the system of stars to which our sun belongs approximates to at least three hundred thousand light years. It is difficult to grasp the full significance Addre3= of this fact. It means that hundreds of millions of the suns of space throng the -Orbil of«?rt2-- visible universe at distances from us and F/pZ Fig.l JjQt from each other running into hundreds, Me tram YSOUiiv thousands and even hundreds of thousands How Star Distances Are Measured by Means of Parallax. of light years. The light waves from some Ylif*) tiny object that we can just barely glimpse We have attempted to grasp feebly the ««n* M-*ta in one of our great reflectors may have vast expanses of time and space that are to My advice to you is to started on their journey thru space over be found within our own sidereal system, start right now to take my one hundred thousand years ago when men but the finite mind of man cannot grasp the HOME COURSE of the Old Stone Age inhabited our planet wonders of a creation in which our entire IN AVIATION earth sidereal system may hold a position as sub- and prepare to fill one of the ordinate as does our own planet in the Astronomers have found as a result of big jobs later. Wonderful op- sidereal universe to which our sun belongs. portunities. Trained men their investigations that the sidereal sys- in biff demand. Prepare The distances of stars are almost incon- now tem to which our solar system belongs is for big future. Lessons are easy ceivable to the human mind. They are to understand. Write TODAY for in the form of a flattened spheroid with its my FREE BOOK. "The Science computed by what is known as the parallax. longest axis in the plane the of Aviat.on," and I will send it of Milky Way. C.pt. G. F. Campbell,, In order to make this plain to the non- formerly Third Ace or and write you a personal letter We have shown in a preceding article on the Royal Flying- Corpa. that will interest you. Address: technical reader, Fig. 1 shows the method the Milky Way how all the various units CAPT. GEO. F. CAMPBELL, Chief Instructor, National used. When the astronomer wishes to Aero Inttitute, 538 S. Dearborn St., Dept. 7445. Chicago of our system, stars, nebulae and star clus- measure the distance of a distant star, he ters are distributed with reference to this takes an exact observation of the star on plane, including our own sun. The extent ** M January 1st when the earth is in position SEXUAL DISASTERS of this star system composed of hundreds C. Then on July 1st he again observes the la something different. Actual cases from pen of a physician. of millions of individual suns in addition Warns you against hundreds of sex evils in very plain lan- same star with very accurate instruments. guage. More interesting than fiction. Sent immediately, to nebulae and clusters is, as we have said, Then he will have an angle A, B, C. The postpaid, for $2 no. MONONGAHELA NOVELTY CO.. Box A-565. MONONGAHELA. PA. at least three hundred thousand light years (Continued on page 56) You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. : ! May, 1919 ELECTRICAL EXPERIMENTER 55 BE THE NAN WHO KNOWS -and Earn Big- Pay By our method of teaching, in your Spare time at Home You Can Soon Be A Trained Man Electrical, Steam, or Marine Engineer, or a Graduate in any of our numerous other Practical Business Courses Business ^Mfijjjjffigfe Today Demands Trained Men — you know that. Your success in life depends upon how well ^° U re are f° r lt ^ ts a question \iA jftTlTEwifery P P of knowing your subject! mm jP& Big business is looking, hunting, advertising—for big, trained men to accept good positions at big pay; such men are scarce hu * there are always Elrrtrtral iErujtnper ; too many of the other kind. W ich ClaSS are r in t0 be in CO^ft^&w^W, £ > °V g° g You want t0 stud y Wltn a Real School. The high stand- .'/jr% , ^^fctathtri tuM '^i, ing of the Jos. G. Branch School of Engineering may be j- - indicated tit- .-! 'i— .1 . by the fact that * *»/ -•- "5 ** We Trained Over for , 1000 Men Government Marine Service ~ZYour Diploma No matter what line of training you need, you will probably find exactly what you want in the list of our courses below. Each course is practical and complete, yet everything is written, illustrated and ex- plained so clearly that anyone who can read can understand it. Everything is made clear. You do not become involved in difficult technical matter which is of no value and discourages the student, but you go right straight through start to the finish from the —and then you've got it ! You can't fail if you will simply do your part, and follow our instruction. THE COURSE YOU WANT IS HERE Complete, Practical Correspondence Courses in Electrical Engineering Marine Engineering Practical Mathematics Stationary Engineering Drafting Ingenieria Electrica Power Plant Engineering Drawing & Designing (SpanUh Course) Power Plant Accounting Practical Chemistry Mechanical Refrigeration VALUABLE BOOKS FREE We have published a Library of Valuable Business Books covering each of the above courses, and we are furnishing a set free to each enrolled student who answers this ad. These are all standard books, each by an authority on the subject. The fnf- tOiif-~_ an rl 1V/I=»"1 Mffc\X/ books above may be worth many times the cost of the course V^M . . .V: _ _***r~_ _ Y._fM_.~ ^/!S~ YY. is the that : Here Library goes with the Electrical course | use this coupon • . Jos. G. Branch School of r> .• i r-i . •. «, r , , w , ! Engineering Practical Electricity I he Electric Motor D.Pt. is, 542 s. Dearborn St.. Chicago Alternation Currents Simplified You mjy send m e. free full information about vour n » • u*s • „ ,. , ,. ,, special offer on course checked below Electric Wiring Practical Mathematics „ctr(cll En eerl s „„ „„ Mlrln , EnalnMrln , Practlcal „„„„,„,„ f Stationery Engineering Drafting Ingenieria Electrica owtr p lan .• 1 ' Engineering Drawing & Designing (Spanish c 1 .i. r- e r 11 I 1 ii. E . Course) bend in the Coupon now for full particulars about the Course yOU } Pmtr Plant Accounting Practical Chemistry Mechanical Refrigeration are interested in. } Name '. The Jos. G. Branch School of Engineering city ...... slate Dept. 15, 542 S. Dearborn St. Chicago, 111. i Present Occupation You benefit by mentioning the "Electrical Experimenter' when writing to odzertisers — — 56 ELECTRICAL EXPERIMENTER May, 1919 ASTRONOMICAL DISTANCES. ELECTRIC VIOLIN-VIRTUOSO A Saved $10022 (Continued from page 54) MARVEL. distance from A to C being roughly 185,- (Continued from page 21) On My Diamond" 000,000 miles, and the angle being known, is obtained by means of a third magnet J85 diamond you sent compares favor* it- is easy to figure the distance from B to which vibrates the tail piece thru the me- InK of J100).—Narae on request. A by means of trigonometry. But if the lis firm i\ ' nearly 3 century old. rated over dium of the shaker bar. JI.UOO.UllU.OO. ' lenda money on r hi Kh gndc jewelry star B is at an immense distance such as Aroazinir. bargains in unpaid loan diamonds" To produce the wonderful orchestral ef- i ' " examination. is shown in Fig. 2, the angle A, B, C be- fects achieved by the Violano-Virtuoso, as Why Full comes very small. As some of the stars Pay Prices the instrument is called, it is necessary to ir vourBelf that Send your are billions upon billions of miles removed iderfuljists free. Every" jewel accurate iy" crlbed in use not one but four bows—one for each detail. Radically differ :t from catalogs. from the earth, it will be readily seen that bee these prices before you buy. string. there will come a point when the angle A, Send for These bows consist of numerous conical Latest List B, ceases to exist. In other words, the 1 C Diamond Loans J'"^^ 11 ^ discs of specially prepared flexible celluloid, monds far under market prices. F-e= ^, distance A to C, altho 200,000,000 miles, nation. Amazing btnraina proved by cus the edge of each disc acting as the hair of tomers letters. Write today. will practically vanish—as it is so little a bow. And it is possible for these revolv- Jos. DcRoi & Sons. 8050 DeRoy BIdg. and the angle becomes so sharp that A, Qify Opposite P.O. Pittsburgh. Pa ing bows to play simultaneously on all B, C is practically nothing but a straight of Reference: Dun'sor BradsireeVa; the four strings. These 4 bows are operated Marine National Bank; Union line. As a matter of fact most of the stars Trust Co.. Pittsburgh. by magnets and are mounted which we see are so far removed from the bow on a bow earth that they have no appreciable paral- shaft extending over the bridge. This, in connection with the fact that the instru- lax, and it is therefore impossible to know ment has sixty fingers against the four BOYS! BOYS! JOIN how many billion miles such a star is re- moved from the earth. As a matter of fact available to the human violinist, is the rea- son why this instrument can, with facility, The JUNIOR YANKS only a comparatively few stars exist that show an appreciable parallax, even with the render the most difficult concertos, etc. Be the firsttoorganizeacompany the master-pieces of the world's musical in your town. A real boys' organ- extraordinary degree of perfection attained ization—no Secure literature some of it is grown-up leaders. an in measuring instruments. Such is the in- — which manifestly officer's commission for yourself. Gei. impossible for four to six boys to join you. conceivable magnitude of interstellar dis- any save the greatest hu- The only boys' organization teaching military virtuosi to achieve. signals, wig-wagging, wireless telegraphy, ma- tances. man chine gun and rifle drill, how to dig trenches, The are automatically make tree entanglements, dug-outs, listening Distances from the sun to the planets and to the bows rosined. posts, how to advance and retreat, do scout ana nearest star in terms of astronomical unit Suspended above the strings is guard duty: all the things a real soldier knows- the the rosin Write today and we will tell you how to be- (distance from earth to sun) and in millions of come box from which the strings automatically a "Junior Yank" and officer, receive tho miles. official Junior Yank Trench cap and collar orna- obtain the proper supply rosin. ments, and a complete military outfit without Table I. of This one cent of cost. is controlled Send ten cents 'stamps or coin) for the official In Astronomical In Million box by a governor and ac- magazine in colors. "The Junior Yank" and a Units Miles copy of the manual drill and rifle cording as the speed of the motor raises or of practice. Mercury 0.39 36.0 Have all your boy friends write at tho same the time. Address Venus 0.72 67.2 lowers— greater the bow speed and the JuniorYanks,202 W. Ohio st. .Chicago, lil. Ear.h 1.00 92.9 closer the box comes to the bows, which Mars 1.52 141.5 by their revolutions against the surface of Jupiter 5.20 483.3 its rosin, Saturn 9.54 886.0 automatically obtain a greater or Uranus 19.19 1,781.9 less supply as required. use HB Ball Bearing Neptune 30.07 2,791.6 Our illustration shows the electrically op- Alpha Centauri (nearest violin, Electric Motors star) 273,000.00 26,000,000.0 erated as well as its accompanying Value of light vear 63,000.00 6,000,000.0 player piano. Both instruments playing to- HB Electrical Motors Save Power—(jet Ball Bearing Parsec 206,265.00 20,000,000.0 gether, thus give rise to a very creditable equipped HB Motors, as they save you a substantial Table II. sum each month on your power bills. Absolutely musical performance. they are trouble -proof, economical, amply designed, Time required to travel from the earth to sun, just right for your requirements—one-half to 15 h.p., moon, planets and nearest star by airplane, (at the they substantially lower your power costs. Easy to rate of 200 miles per hour), and with velocity of ALL KINDS OF LIGHTNING. install and operate. Require practically no attention. light, (at rate of 186,324 miles per second). $20.00 gives you an HB Ball Bear- (Continued page ngfWotor. The balance on easy To By airplane With velocity from 20) terms. Suits your requirements. of light Le tour engineering depanmentadvise denly took it into his head that he was go- State Moon 7 weeks 1 seconds you. Send In your problems. % ing to take some superlative lightning kind of machinery you wish to run and Sun 52.99 years 7 min. 59 sec. photos type of current available. Can also furnish Battery Charging Outfits. Venus 14.37 years 2 min. 18 sec. on a certain summer day. In this particular Lighting Generators, etc. Pin thisaa Mercury 32.46 years 5 min. 6 sec. to your letterhead and mall for further instance, the thunder storm had not been be- Mars 27.72 years 4 min. 21 sec. Information today. having very nicely, according to the pho- HOB ART BROTHERS COMPANY Jupiter 222.68 years 35 min. 15 sec. Box5£ Ohio Saturn 452.37 years 1 hour 11 min. tographer's notions, but he thought he Troy, Uranus Sueesssfui Manufacturers Since 189S 963.38 years 2 hours 32 min. would take a chance any way. We might Neptune 1,539.30 years 4 hours 2 min. mention before going further, that the Alpha Centauri 145'i million (nearest star) years 4.35 years thunder storm did not come up in the usual Note: The above results were obtained by way, and proceed to discharge veritable using the mean distances of the planets from the Earn ?35.to forked "Bolts of Thor," but satisfied itself 10.WEEKLY sun and the nearest approach of the planets to You can make $35.00 each other. with merely hanging around in the offing, to $100.00 a week. I want hustlers, and giving a perfect imitation of the best money-makers, to work flash, or so-called lightning, with me, to advertise, sell RELIEVING THE CAR CRUSH. "heat" you ever and appoint agents. Big- (Continued from page 15) saw. What happened was this. The pho- gest thing inyears. City conveniences without lide! The westerner wants to get off and tographer waited until several of these plumbing. Used in any room. the easterner wants to get on, naturally. flashes had occurred and the rain had be- _ ells on sight. l>emonst ratine tub furnished. Folds small, self-empty- Now an old axiom says that one mass gun to fall, when he thought the lightning ing, non-leaka.l>le. Guaranteed 10 years. can't take the place of another mass with- discharges would sharpen up enough to AGENTS MAKE SALES EASILY out displacing that first mass. But tho we photograph most beautifully. However, he Two sales daily means $60.00a week. Leggett, Ohio, "Worked two hours, took two orders, profit $10.00." Hayhurst, Ntbr.. have learned in our physics class that miscalculated the extent and the frequency l "Took 11 orders in 4 £ days—profit $D5.00, ordered 12 more water is not compressible, Subway pas- of the flash lightning, which in this par- tubs." Manning, Inwa, "Sold. 10 tubs in one day—profit »50.00." DeHut. Nebr., "Soldl2tubs in three days—profit sengers are compressible to the Nth degree. ticular case hung on for a long time, and iGO.00." And Luidrc la of others making big money. "Opcroentof homes have no bath tubs. Experience and capital untiMeiesry. Credit Then after a homeric battle in which accompanied each flash of forked lightning, ii»t f> 'i particulars and given to the right man. "special plsn;"s11 Fart. both sides display a titanic amount of which was rather slight in quantity, with H. S. Bobinson, Pros., THE ROBINSON CABINET MFG. CO. ^STSFjclorlo^lllldln^^^^^^^^JLEDO^HIO muscular effort the "westerner" is finally the total result that after six 8x10 nega- ejected forcibly from the car and a half tives had been exposed, and then rushed training again open to ELECTRICAL civilians. Over 3000 men dozen "easterners," with the "gentle" help expectantly into the dark room and de- iramed for electrical in- of the subway gladiator, are packed into veloped, they dustries in experience of more than a quarter of a century. showed,—what do you sup- For men of ambition and limited time. Condensed course in the train, which proceeds on its way until pose? Well, sir, those six plates turned out Electrical the next station, where the same little to be six of the finest snap-shots of the ENGINEERING g£g game of forcible subtraction and addition surrounding landscape and buildings that good positions and promotions. Theoretical and Practical is enacted all over again. you ever laid eyes on. By actual compari- Electricity, Mathematics, Steam and Gas Engines, Mechani- cal Drawing. Studehts The cure? There are three doors on son you could not tell them from a sunny construct dynamos, in- each New York subway car : Two on each mid-day snap-shot of the surrounding coun- I YEAR stall ONE wiring and test electrical machinery. Course with diplo- end and one (about the same size as the try taken with the same camera. ma, complete. front and end door combined) in the cen- Thus the Thoroughly equipped fireproof dormitories, motto would seem to be, that to dining hall, laboratories, shops. ter. If the outgoing passengers could use, obtain good lightning photos, one should Write for catalog. 27th year opens October say, the doors only the 1. 1019. end and incoming take advantage of a very dark overhanging BLISS ELECTRICAL SCHOOL travelers the middle doors only, and if this storm which gives the greatest contrast of 260 Takoma Avenue, Washington, P. C. rule would be strictly enforced, don't Comics. Cartoons Commer- you course, for the lightning flashes to appear cial, Newspaper and Maga- think that this would help to make the Sub- against. At night would seem to be a most zine illustrating. Pastel, Bc-ojvx. Crayon portraits. Poster way a better place to travel in? opportune time to photograph lightning dis- and I'.i-li.ms Earn Bik Money. Tauijhtbu Mail or LocalClasscs. And, besides, Kipling would be right. charges, but many excellent pictures have !" Write for illustrated booklet, "East and West, they never shall meet terms and list of successful pupils been obtained in the day time as well, un- ASSOCIATED ART STUDIOS. I3A Flatlron Bldg.. N. Y. Anyway, not so rudely! der suitable conditions as just outlined. You benefit by mentioning the ''Electrical Experimenter" when writing to advertisers. — May, 1919 ELECTRICAL EXPERIMENTER 57 Taught By a Practical Man and in Your Home! ' ;m vertisement, that you will send for my catalog which tells what I am en- deavoring to do and also places before you the simple way in which the instruction work is handled. The catalog is written in a very plain manner. much in the same style as m> lessons are written, and tells you exactly what you get and what the course can do lor you. My catalog, as well as my advertisements, is written in a very careful, conservative manni there is no possibility of you expecting something you will not get- sons are rL arcd especially for the purpose for which they arc Triei ne Purnoserurpose oiof the v-ourscCourse uiof oiuuyStudy P P me . is tni individual jnJ addiliona , instruction rf^ lo Btu- 1 teach- I ha igning courses in electrical in.-truction and dent, with a view of meeting hi- particular need-. 1 have th_- ing electricity, of! and on during the past 17 year?, and during information to give and I believe the ability to impart it to that time 1 have had an unu-ual opportunity to make a special others, a fact which is in a way proven by other institutions study «ii iiu teachin from tin standpoint of a practi- which have made use of my services in the design and perfect- cal man. This course of my own i- designed with a view of fag f instruction courses. To understand this wurk. IT IS UP reaching those who do not have a lot of time and money to JO YOU to stick with me and I will surely stick with you till devote to study work, and to give them as thorough a knowledge you understand any part of the work you have gone over, ' as possible of electricitv, in the possible time. The . . . - . . _ . shortest n ., _ ,, , n instruction is given like you were working on various jobs, Practical IVlen lake IVly Course and Kecommend it to Diners giving the explanation necessary for the understanding of the sixlv percen t f mv students arc actively engaged in electrical theory covered the subject There are by under discussion. work an<] nn(i lhe 'instruction I give well suited to their needs. conditions every run of many which seldom occur in the day Several of these men have had their fellow worked take the electrical experience, these condition:- 1 Ia> particular .tress , and course a so and thcy are taking the instruction together making on. This part ol the instruction makes the course particularly a class-room proposition of it and the results are in every Way attractive and valuable to those already in active elec- engaged satisfactory to all concerned. One of these classes was started tncal work. by a chief Electrician, one of my students in Glen White. W. \ a . It Is Up To You wno nmv ^ as practically all the men under him taking my course. I believe the fact that these men who understand electrical work The instruction work is laid out and given in a way easily approve of my course to this extent is one of the strongest understood. It is not a cut and dried book plan, but the les- endorsements I could get. What Electrical Men Say Of My Course In my catalog are letters from men I ham taught, »mi being men I bsea position as waiter and am now employed as electrician in tin- Car-It..?, Rliz I taught when ici Institutions wars aun. printed bo far like* the and work rery much u.'!. bee regards I an You i [en of showing you thai 1 ban netting the Has Bnglemaa." 1 -' here ex racts from er from Mr Bnaleman about a week later "Tom Lessons together letters idents from winch you will with your i Blue Book i sry much anl I think it la Ilk.- unour electrical course you offer a most practical system of who work under him. "I am just in receipt of your valued letter a training for anyone In the electrical work. 1 would refer you to a young man here than pleased with the suggestions and Information -i in Uoi set ire an In si hoal Bit i i . enrollment pour aun a thai shall do all thai Is ; . lt , nt M Blratton Irani Waller Lime much myself. Speaking of the lessons. I have never seen anything i blm to you as I have already recommended your as Interesting as they are. an. I. as I ui-t as aoon an I ruin after It school very highly.'' I ami don'l stop until thii I :,r.,l the siH This letter hi from Johi srrall. Pennsylvania, "I am writing this manager looked over our lessons last night and be iinl sol hesitate In so In thai »w me better and know I am earnest In taking this course. the lessons were the best that he had ever seen He Is a college man with I am a foreman in this riant am] all I have learned Is through practice and that number of real ' experience In the engineering business and knows a good thin.; Is ' \ at tins the reason 1 want to lei lam Cbiel .- when be sees II and I feel rare thai b your work a l plant said to me thai he bad taken course Borne time ago and asked blm within tin We received the returns on the last lessons and all of us lurse and he >U This man worked under are more than pleased with the work that you are giving I never saw a more I working him I me sometime ago and now am under and do not want It to enthusiastic bunch of men than they are over the lessons and everyone Is buckled happen again." down to work and Is going to try and make good. Fit mysell I wish to sav tha- i . from Max Qigleman, New lort City "Tour Oral Installmenl on I took s course some yean ago In electric railways and i have l I wcnl to work and liked thi I b d ol your gotten more ol out your lessons thus far and 1 know that if I live unin I com- Insjtructlons vers well. STou will find the answers i" the examination plete this Questions course, with the knowledge thai I will gel oul ol it connec ed with the uMucht'd i" tins letter. I .. liter uii'l would be only too gla the privilege of discontinuing the work if they should find that it was not just what I they were after, and their payments stop at the same time. This is my way of I Gentlemen: and I would want doing business not your money when I was not giving you' the Sen-I me catalog describing your course in Electricity instruct | an d Drafting Apparatus, Instruments, Material, Etc. | Certain electrical apparatus, instruments, material, charts, drafting implements, etc., i ' as detailed in the catalog, are included in the course and are a part of the regular ' instruction f'>r there is extra as it which no charge is covered by the regular | ADDRKSS monthly payment I FILL OUT COUPON FOR ONE OF MY CATALOGS WHICH GIVES FULL INFORMATION ' , ,,-y BURGESS ELECTRICAL SCHOOL STATE 745 E. 42nd St., Chicago, III. You benefit i\\ mentioning the "Electrical Experimenter" when writing to adverttsei ) ; 58 ELECTRICAL EXPERIMENTER May, 1919 ^- It contains the follow- ing 44 chemicals: Q3D 323 •"* Alum AI 3 (S04 ) 3 , (NHJsSOj Antimony (powdered) (Sb) «s; Ammonium Aqua r (NHa+H-O) Ammonium Carbonate Glycerol ( Glycerine) C3 H B (OH) 3 We present herewith to our friends our new E. I. Co. Chemical Labora- Hydrochloric Acid (HC1) Iodine (I) tory which contains real chemicals and apparata to perform real chemical Iron Chloride (FeClo) experiments. This outfit is not a toy, put up merely to amuse, but a Iron Oxide (Feo0 3 ) Lead Acetate Pb (C 2 H 3Oo) J practical laboratory set, with all the chemicals, apparata and reagents Litmus Paper Magnesium Carbonate necessary to perform real work and to teach the beginner all the secrets (MgC03 ) of inorganic chemistry. With this outfit we give free a book containing Manganese Dioxide (MnOj) Mercury (Quicksilver) (Hg) a Treatise in Elementary Chemistry, useful data and recipes, and 100 Nickel Chloride (NiCI 2 ) instructive and amusing experiments. Oxalic Acid (H2C2 4 ) Sodium Bicarbonate (NaHC03 ) Sodium Borate (NaBOo) DESCRIPTION OF THE OUTFIT: Sodium Carbonate (Na^COa) Sodium Chloride (NaCl) The outfit consists of forty-four (44) Chemicals all A good part of the book is devoted to Weights and C. P. (chemical pure) put up in appropriate wooden system Sodium Nitrate (NaN03 ) Measures. The Metric System, the English Sodium Phosphate boxes, glass bottles, and hermetically closed jars. The and the U. S. System are fully explained. acids are put up in glass bottles, with ground-in glass (Na 2 HP04 ) Sodium Sulphate (Na-SOj stoppers and there is a sufficient quantity of chemicals The following tables are furnished: Symbols and Sodium Sulphite (NaJSO.-O supplied (mostly one to two ounces) enough to make Atomic weights of the Elements; Measures of Weights, dozens of experiments with each. See list of Chemi- Stannous Chloride (SnCl.) Volume, Capacity and Length ; Per Cent solutions Sulphate of Nickel 231 STREET NEW YORK CITY TRADE MARK TRADE MARK FULTON See our full page Ad, on page 88 for Free Cyclopedia You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. May. 1919 ELECTRICAL EXPERIMENTER 59 Will Maim Freeze the EartH to DeattlK? i c ontinutd from pat Rising price* and increasing scarcity of the Pacific Ocean, with thi- resultant surely will drive Us to other fuels. Alcohol dl ot live steam and poi - tl has been cited as a probability, mainl) lie- ing the earth and killing all animal and cause it can be produced anywhere crops 'able life, would be the gn at del are grown. The truth of this matter is that ; to be dreaded. Taking all into if the fuel requirement! of the world were ration, radium seems like the best and EARN $35 TO $100 to be supplied by the world's crops there t possibility. would be no crops left to feed the world's < Ine strange possibility which has an inhabitants. equally queer parallel in the case of radium PER WEEK The final summation simply is that when extraction on a large scale is the quick coal and od both give out we will have an doom which would face the earth if men As a Mechanical Draftsman era of substitutes beside which the war piped all their heat from the earth's in- bread of the past vents year will be heavenly. terior. Providing millions of these Thousands of Men Wanted We will scratch around, burn up all our for power uses on all continents would cool forests, dig our peat bogs to the bottom, the iron center of the earth speedily. You can learn Mechanical Drawing at home and do what we can to find other sub- Under the present scheme of things. Pro- in your spare time through our practical Home stances to supply the deficiency. All the fessor Maurier estimates that the earth will Study Course and qualify for Big Pay. We substitutes will be costly, both from point cool to the temperature of the moon ( — 110 have placed hundreds of our students in good of view of actual price and in point of degrees Centigrade) in twenty-eight million paying positions. Government departments and efficiency. Those who cannot afford to use s. Human life as we know it will have private concerns are continually calling upon will them simply have to move toward the been extinct, in all probability, for twelve us for our graduates. equator or freeze to death. or thirteen million years of this term, unless Radium is the one direct answer to the man finds some material in which to clothe Become a Chief Draftsman problem raised by this situation. True, it himself thru which body heat cannot pass, and get to the very top in this well-established exists only in minute quantities in the and grows his crops in huge heat-insulated rapidly earth's crust. True, under our present sys- greenhouses. and growing profession. The training given by the Columbia School of Drafting will tem of extraction it costs prohibitively. I f the vents were opened, however, the Still, it is the only logical answer. heat of the earth's center would flood the give you just the knowledge you need to make Why? While radium is present only in atmosphere, even if used as economically as good as a Chief Draftsman. No previous train- proportions of from one to three grains per possible. It would rise to the outer edges ing is necessary. You can begin our course now ton in the outer thirty miles of the earth's of our air, coming into contact with the and make rapid progress from the start under crust —excluding the oceans, of course, in bleak (absolute zero) temperatures of the the Personal Instruction of the President of the which there is only a trace—there is suffi- void, and cooling. Instead of the gradual School, Mr. Claflin, by mail. His carefully pre- cient of it in the millions of years, upper two miles uf crust to change extending over pared lessons and personal letters of advice supply all possible would confronted a situation to power wants of man. man be by make each step easy and interesting. The fact that it now costs us over a half- which he probably could not adapt himself. million dollars a pound to extract it is no The end of the world would come in ten Draftsmen Now Getting argument. The scientific brains of the thousand, yes, perhaps in five thousand to a world never has been focust on the problem years. $35 $100 Week of securing radium. Only the inventive Even if the radium power system were with big chances for better pay as the demand skill of a small number of people has been inaugurated, something similar might take grows. All big engineering, construction and concerned with the processes of mining and place, tho by no means as suddenly. Radium manufacturing projects must first go through extracting any kind of precious metal. apparently was placed in the earth's crust the drafting room before the workmen can With only a few dozen laboratories in the for one particular purpose. That was to commence. All such enterprises depend upon world knowing anything whatever about keep the earth from cooling off quickly. large numbers of draftsmen. Salaries are ad- radium, the cost of securing the metal has W'e have seen that twenty pounds of vancing steadily. been cut in half in the last four years. In radium would equal nine tons of anthracite the event that radium showed itself to be in a year's time. The amount of radium in Drawing Outfit Free with the only salvation for men outside of the the thirty-mile crust of the earth, according Our Course equatorial zone, would not this cost be to Professor Henri Becquerel of the French As soon as you enroll you will be sent our slaughtered? Would not radium be ex- Academy, is sufficient almost to equalize drawing outfit for your own use throughout tracted by the ton instead of by the milli- the daily loss of heat thru the atmosphere! the course. This entire outfit will be yours to gram? When it is considered that by the That means that if there were a little more keep. You are not obliged to return it after extraction of all the radium in a belt of radium in the earth this planet never would completing the course. land, ten miles wide by three miles deep, cool off at all! Also it means that if the extending around the earth sufficient of the earth were of the same consistency all the Not Only a Correspondence School metal would be secured to run civilization way thru, and not mostly molten iron or The Columbia School of Drafting is proba- just as it stands until eternity, without fur- steel, the amount of radium being of the bly the largest residence school in the ther outlay for power of any kind, does same proportion as at the surface, the globe country specializing in the training this seem impossible? It would be an would get hotter constantly. In the course of professional Draftsmen. undertaking, for centuries, undoubtedly, but of a few decades or centuries it would Our Home Study Courses are an what of it? There would be little or no burst into flames and burn to a cinder. extension of the same instruction as given depreciation in the metal secured year by The big point for us to grasp, however, locally. year, and every tiny particle mined and ex- lies in the fact that we are living now on tracted would do away with the necessity earth solely because the crust contains Illustrated Catalog FREE for just so much other fuel. In case the radium. If this had not been the case the Simply fill in the coupon below, return it to were started under Government or earth would have become cold and project dead us and we will send you free a copy of our other competent supervision, the probability eons ago. If man. for any reason, becomes illustrated catalog which tells all about our would be strong that the descending price rasping or in such dire necessity that practical Home Study Course and how you curve of radium would cross the rising he extracts all of the radium from the may secure our instructions at once on easy curve of other fuels in the course of from crust, he simply will be limiting his chances terms so as to quickly qualify for one of the fifty to one hundred years. of a long stay very definitely. big positions open. The only alternative to this desperate This, however, is a remote possibility. offered de- The radium is scattered thru plan that seems to be to our the whole Send This Coupon Today. scendants is the piping of steam and hot air crust to an average depth of thirty miles. from the earth's interior. On a small scale v tlii > there is a highly heated tho COLUMBIA SCHOOL OF DRAFTING this has been done already in Italy, but solid zone in which there probably is a cer- Dept. 982. 14th and T St.., Washington, D. C. scientists have pointed out that serious dis- tain amount of radium. This zone extends turbances, earthquakes, cracking of the eighty miles in depth, and below it is molten \\ itlmut obligation to me, please send me your crust and other disasters involving huge iron, the core of the earth. Man will have Illustrated Catalog and tell how I may secure your losses of human life would be certain to his hands full extracting the radium from practical braining in Drafting and your help in securing a position as Draftsman. follow the experiment of trying this on a the upper two or three miles of the crust. large scale. The trouble mainly would be Since this will give him all he ever can caused by the sudden cooling of certain need, unless the demands of future civiliza- portions while the other parts remained in tion grow much faster than any of our Address a molten state. The great catastrophe of a estimates figure, he would not touch the tremendous crack appearing in the middle greater portion. City State. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. — 60 ELECTRICAL EXPERIMENTER May, 1919 " The National Authority on Electric " New YoirUt A,© Wirin£for Twenty-Five Years §Ih©w All You Need to Know About Wiring (Continued from page 19) is in the Latest Edition of ily imagined for the visitor was shown a complete composite photographic map of "Standard Wiring" the city of Washington, D. C, which was taken from an airplane in a trip lasting but two hours and fourteen minutes. Hundreds year's edition, completely revised THIS of photos are taken by the rapid-fire cam- to date, is the only accurate book on eras, and after developing and printing electric light and power wiring and these have to be evenly matched and as- construction published. sembled. Large photographs taken about The National Electrical Code, with all its New York along the river, showing the new rules, is explained and illustrated. 52 ferry boats, etc., were taken during the of the latest and simplest tables which afternoons of the different days, and the show, at a glance, just what size of wire is plates would be rushed to the aero show, needed for any kind and size of lighting there developed and finished and prints or motor installation, for any voltage, cur- made by the Army's photographic experts, rent and drop desired for any system. Di- the mounted photographs being on exhibit rect Current, Alternating Current, single, at the show in from one hour to an hour two or three-phase. The latest Code Rules and one-half after they had been taken by on grounding required on all work. the aviator flying above the city. The machine gun exhibit attracted much How to install and operate generators, mo- attention, particularly the means for tors and every kind of wiring device with used synchronizing the diagrams of connections. Special chapters two machine guns on battle-planes, so that they both fired dead on illumination. House Wiring, Electrical ahead and thru the revolving propeller, the Units and their Equivalents. The latest bullets passing accurately thru the spaces lamp data. Proper symbols to use to indi- between the blades every time these spaces cate outlets, etc., etc. came in line with the machine gun barrels. It Will Make You an Expert The Packard Automobile Company, makers Wireman of the well-known Packard motor car, ex- hibited a new pleasure and battle-plane fitted with the Packard 12-cylinder aircraft Leather Cover - Pocket Size - 375 Pages - Price $1.50 engine, which somewhat resembles the Liberty motor. The Liberty motor, which Sent to any address, postpaid, on receipt of price was on exhibit, attracted considerable at- tention, and the number of these motors H. C. Cushind,, Jr., 10 West 40th St., New York built by each of the large automobile con- cerns during the war were shown. There was a large sea-plane on exhibit which had flown to the show. Speed enthusiasts in the flying world had their attention riveted on what was pur- ported to be the fastest airplane in the world, the "Christmas Bullet," a small model of which was exhibited at the Aero ^FREEthc Show. It was very well built, and the most remarkable feature of the design of the 71 DON'T WEARATRUSS "Bullet" is that there are no struts between the planes, and also there are no guy wires, as in the usual types of monoplanes. The wings are supported by the cantilever prin- ciple, and besides they are flexible. The "Christmas Bullet" bi-plane is guaranteed to PLAPAO nUDES make 200 miles an hour, and it attained a THIS speed of over 185 miles per hour on a recent Inner surface made self- THROUGH adhesive purposely to prevent OPENING A trial flight, when equipt with a six-cylinder constantly applied slipping and to keep 185 H.P. Liberty motor. It is claimed by its the absorbent - astringent medication called PLAPAO. Close the hernial opening builders to be the safest and fastest airplane as nature Intended eo the Rupture CAN'T in the world. Not only this, but its lifting come down. capacity compared to its size is greater than that of any other 'plane, it is stated. As will Do Away With Steel and Rubber Bands That Chafe and Pinch be evident, this ingenious design of 'plane is You know by your own experience that the truss is a mere makeshift—a false prop against constructed on the principle of true bird a collapsing wall—and that it is undermining your health. Why, then, continue to wear it? flight, therefore it self-balanc- STUART'S PLAPAO-PADS are entirely different—being medicine applicators made self- which makes adhesive purposely to prevent slipping and to hold the distended muscles securely in place. No ing and serviceable in any kind of weather. straps, buckles or springs attached. "digging in" or grinding pressure. No Soft as Velvet— Flexible The wing surface is 170 square feet, and —Easy to Apply— Inexpensive. Continuous day and night treatment at home. No delay from work. total is Hundreds of people, old and young, have gone before an officer qualified to acknowledge oaths, and the weight 2,100 pounds, which in- swore that the PLAPAO-PADS cured their Ruptures—some of them most aggravated cases—and of cludes fuel for three hours. long standing. This airplane is intended to play the role Send Today For FREE PLAPA0--No Charge for it--Now or Ever of the first "taxi-plane" ever used in steam- ship service, and is to be operated at the Simply write your name and address below. Send this advertisement for absolutely FREE TRIAL port of New York by one of the leading PLAPAO and 48-page Book on Rupture. No charge for it —now or ever. Nothing to be returned. "Be wise today 'tis madness to defer." Address. PLAPAO CO.. Block 844. St. Louis. Mo. steamship companies for overtaking a ship Name Address a day out at sea with sacks of belated mail, dispatches, etc. Among the interesting airplane engines exhibited at the Show was the well-known T TLE EFFORT "Dusenberg." This Company exhibited a TO INCOME A DAY MADE powerful new model 12-cylinder aircraft en- ADD YOUR $5 t0 $To EASY WITH gine, in which each set of six cylinders operated a separate crank shaft of its own. New Improved Green Automatic Machine The power from the individual crank shafts Sharpens. Hones and Strops all kinds of safety razor blades, in one operation, from four to sis blades per minute. For both Quality and Quantity, this machine* was then transmitted to the propeller shaft is in a class by itself. There is nothing like it on the market. Let us send you by means of two gears, one on each side our free booklet explaining everything including the "AMERICAN" Key Cutter cuts square, angular or round slots. of the main driving gear secured to the AMERICAN SHARPENING MACHINE CO. (Inc ), Dept E E, 184 W. Washington! St., CHICAGO propeller shaft. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. May, 1919 ELECTRICAL EXPERIMENTER 61 The True Wireless By Nikola Tesla [Continued from paye 30) wanted: ornce MEN Auditors, Accountants. Office Man- Which Job trau-.s • an ' arrangement described in my I aitera. Crrdit Men. Cashi' era and Cost — Patent No. 568178 of September 22, 1896, Clerks S1.2U0 lo $7,500. and corrcspoixHnvr dispositions' of wireless rnCTOQT HEN Electrical and Mechanic*] KnRineers. Fac- apparatus. The caption'. . >t' the individual tory Managers, Superintend".- ' i diagrams arc thought sufficiently explicit to Designers. Draftsmen— $1,500 to $12,000. Can dispense with further comment 1 will CONSTRUCTION HEM Civil merely remark that in this early record, in and Structural Engineers, Transit. nv-n. Construction addition Supcrmtrndents and (O indicating how any number oi Foremen, Estimators, Dt-signcrs and rconant circuits may he linked and regu- Draftsmen — S1.2O0 to $10,000. lated, I have shown the advantage of the TRADES — Machinists and Tool- proper timing of makers. Auto Repairers, Electri- primary impulses and use cians. Stationary Lnitifwra. oi harmonics. In a farcical wireless suit in 1 IMUMU, I'lumbcrs, Car- penter*, etc.— II, LW don, some engineers, reckless of their to com. reputation, have claimed that my circuits were not all as- Fill at attuned; in fact' they serted that I had looked upon resonance as All a sort of wild and untamable beast I these It will be of interest to compare my sys- positions Which one of them could tem as first described in a Belgian patent were advertised of 1897 with the Hertz-wave system of that jyott fill? If you haven't the period. The significant differences between in a single issue knowledge necessary to them will be observed at a glance. The break into the big-pay class, first enables us to transmit economically of a Chicago decide to get that knowledge energy to any distance and is of inestimable These newspaper NOW! Any of the books value; the latter is capable of a radius of books only a few miles and is worthless. In the listed below will quickly fit were writ- # first there are no spark-gaps and the actions you for a well-paid job—at home are enormously ten by ex- magnified by resonance. In —in your spare time. both transmitter and receiver the currents perts in plain, are transformed and rendered more effec- everyday language. They are Carpentry and Fire Prevention tive and suitable for the operation of any free from puzzling technical Contracting and Insurance desired device. Properly constructed, tm Five volumes. 2138 pages and Four volumes, 1500 pages and more than 400 illustrations. 600 illustrations, diagrams, system is terms. Numerous illustra- safe against static and other in- Prepares for Contractor. Build- form., etc. Prepares for Count- terference and the amount of energy which tions, diagrams and tables inir Superintendent and Car- erman. Rats Clerk, Inspector or Agent. Regular price. be transmitted may is billions of times make difficult pnce.J25.00.Specialpnce.n-.sO. J20.00. Special price, 115.80. greater than with the Hertzian which has points as simple Civil Engineering Electrical none of these virtues, has never been used Engineering asA-B-C. They Nine volumes, 3900 pages and Seven volumes 3000 pages and successfully and of which no trace can be 3000 illustrations, plates and 2O0 illustrations, plates and found at present. are handsome diagrams. Prepares for Civil or diagrams. Prepares for Elec- Structural Engineer, Transit- trical Engineer, Power Plant A well-advertised expert gave out a state- ly bound in man, Estimator, Designer or Superintendent. Substation Op- Chief Draftsman. Regular erator or Electrician. Regular ment in 1899 that my apparatus did not price.S15.00. half or full S pedal price.J29 .80. price ,t35.0). Special price .HS.60. work and that it wouid take 200 years be- (ex- Telephony Accountancy fore a message would be flashed across the leather and and Telegraphy Business Management Atlantic and he even accepted stolidly cept Law my Four volurr,. --. 1TJ- pa^cs ar,d T.T ilijrftratiossj, <•-. congratulations on a supposed great feat. and Practice, 2 Plata and 1.--7 1. steal --. f -,..= diagrams. Prepares for Tele- But subsequent examination of the records which is Engineer. Wire Chief. Accountant, Auditor. Office showed that my devices were secretly used xchange Manager. Trouble Manager. Accountant, Credit bound in law Uan or'telegrapher. Regular Man or Bookkeeper. Regular all the time and ever since I learned of this pnce.J20.oaSpecialprice,iliS0. price.J50.00.Specialprice.l24.SO. I have treated these Borgia-Medici methods buckram) and with the contempt in which they are held stamped in by all fair-minded men. The wholesale gold. Fill out One appropriation of my inventions was. bow- the coupon. ever, not always without a diverting side. Week As an example to the point I may mention Automobile my oscillation transformer operating with Engineering an air gap. This was in turn replaced by Five volumes, 2400 pages and Seven volumes. 3300 pages and Free 2000 illustrations. Prepares for 2SoO illustrations, plates, dia- a carbon arc, quenched gap, an atmosphere Garage Foreman, Automobile grams, etc. Prepares for Sta- of hydrogen, argon or helium, by a me- Mechanic or Chauffeur. Inval- tionary, Marine or Locomotive uable to car owners. Regular Engineer or Fireman. Regular Trial chanical break with oppositely rotating price ,$25.00. Special price. J17.&0. price ,$35.00. Special price ,$21.o0. members, a mercury interrupter or some We'll gladly send you any set Machine Shop Practice Law and Practice for kind of a vacuum bulb and by such tours seven days' examination. Don't send Six volumes, 2300 paces and (with Reading; Course in 25 de force as many new "systems" have 1 •J&i-O illustrations. Prepares for bound pamphlets). Thirteen us a penny; just pay the small ship- Machine Shop Superintendent volumes, pag-es and 2: illus- produced. I refer to this of course, with- 0000 ping or Foreman, Foundryrnan, Pat- trations. Prepares for all Bar charge when the books arrive. out the slightest ill-feeling, let us advance tern Maker, Tool Designer or Examinations. A wonderful Examine them carefully— use them Tool Maker. Eevrular price, aid to business men. Re>rular by all means. But 1 cannot help thinking 130.00. Special price, fh'.sO. price. $72. 00. Special price. j-^.i-O. at your work for an entire week- At how much better it would have been if the Sanitary, Heating and Practical the end of that time, if you feel they ingenious men, who have originated aren't worth tl Ventilating Engin'ring Accounting far more than we ask, return "systems," had invented something of their Four volumes, 1454 pages and Foot volumes, 1S^0 pages and them at our expense. If you keep them, pay the bargain own instead of depending on me altogether. more than 1400 illu 800 illustrations, plates and price on the easy etc. Prepares for Sanitary diagrams^ C. P. A. questions terms explained below. Before 1900 two most valuable improve- Engineer, Heating1 and Venti- ana practical problems. Pre- lating E n B_i neer, Master pares for Accountant. Book- American ments were made. One of these was my Plumber or Plumber. Regular keeper or Cost Clerk. Regular Technical Society individualized system with transmitters emit- price,£20.00. Special price, $13.30. price, $20.00. Special price.S12.8a Deal. X338S Chicago. U. S. A. ting a wave-complex and receivers compris- americanTachnical ing separate tuned elements cooperatively 50c A WEEKT Society, De»l. X3345, Chicago, III. PI associated. Yes. if ! **. •>'-:.—• The underlying principle cat you decide to keep the set you I ,„, J*;:±;'" HJ c : have explained in a few words. Suppose that selected, send $2 within seven | ta^fta^'rS^XJ^^^^^^ days and then S2 a month i50c a ««*) , ,. „ ,„. there are n simple vibrations suitable prW „_ „ , Mim ^ ^ for until the present price I will return tS«-iribr low has been KprvM at your 'iptoM. TUU Dotloput to m* imul ™"lb* use in wireless transmission, the probabil- paid. Have you ever heard of a more Mt i* fully pfcJd foe. ity that any one tune will be struck generous offer? Remember, you take by an no chances whatever— we send the books for 1 examination and you are not obliged to keep extraneous them if you do not care to buy. Hail the disturbance is —. There will coupon now—before you turn the page. n _.j then remain n—1 vibrations and the chance 1 Learn Watch work, Jewelry work and that one of these will be excited is , A flne mde command! a good aal- We write music, a-.iigiaviugFnoravina rn guarantee publisher's acceptance. ary, and your urrteea Is )i— 1 axe always Submit poems on patriotism, love or any subject. demand. hence the Address H0R0LO0ICAL Department. CHESTER MUSIC COMPANY probability that two tunes would Bradley Institute. Peona. m . (or our latest catalog 918 S. Michigan Ave. Room 313 Chicago. Illlnoli , . ! May, 1919 62 ELECTRICAL EXPERIMENTER 1 be struck at the same time is . Sim- FOR THOSE WHO n(n—1) ilarly, for a combination of three the chance LOVE GOOD MUSIC 1 -will be and so on. It will be n (n— 1) (n—2) readily seen that in this manner any desired degree of safety against the statics or other kind of disturbance can be attained pro- vided the receiving apparatus is so designed that its operation is possible only thru the joint action of all the tuned element.. This was a difficult problem which I have suc- cessfully solved so that now any desired number of simultaneous messages is prac- ticable in the transmission thru the earth as well as thru artificial conductors. The other invention, of still greater im- portance, is a peculiar oscillator enabling the transmission of energy without wires »» in anv quantity that may ever be required Master for industrial use, to any distance, and with The Ellis "Music very high economv. It was the outcome of years of systematic study and investiga- Reproducer tion and wonders will be achieved by its means. Will make your Talking Machine The prevailing misconception of the mech- Artist "The Soul of the Living anism involved in the wireless transmis- been responsible for various composition as orig- sion has a i ordinary sound-box can reproduce unwarranted announcements which have The true tone colormg NO played or sung by the artist. and worked harm. By inally it not misled the public overtones completely lost. And is lacking—the beautiful keeping steadily in mind that the transmis- reproducer vibrates, causing a oerfecth° adjusted the ordinary sion thru the earth is in every respect commonly associated with mechanical Tarsh and shrill tone so identical to that thru a straight wire, one will gain a clear understanding of the phe- Master" Reproducer all this is correctly "But with the Ellis "Music nomena and will be able to judge that ongmaUy went into changed Every shade of expression the merits of a new scheme. Without wish- ing to detract from the value of any plan that has been put forward I may say that of novelty. So for instance or they are devoid were in your home, playing transmitting and exactly as if the artist himself in Fig. 12 arrangements of which 1 singing at his very best. receiving circuits are illustrated, For all machines— have described in my U. S. Patent No. You must hear the "Music-Master to all Records 8, 1898 on a Method great merit Plays 613809 of November apppreciate its talk- what style, size or make of for Controlling Mechan- No matter records of and Apparatus of hard study and have if it "?es disc It took 10 years ing machine you and Vessels or Vehicles, and experimenting to develop this you can use Ihe Ellis "Music-Master ism of Moving constant put on. it pro- brings to enjoy the real music. Easily recently dished up as orig- one reproducer that faithfully because it is which have been lines the lite of the records, there is in the record. other reproducers tech- life all much lighter in weight than inal discoveries. In other patents and to you an ade- cannot afford Words cannot convey And the price is so low that you suggested conduc- wonderful will double the worth of nical publications I have quate idea of how much this to be without it—it the obvious device will do to improve the playing your instrument. tors in the ground as one of it- of records. You must see it—hear Write today for full details modifications indicated in Fig. 5. all compare the effect with any and to the Thousands of satisfied users attest you know of; then to sena reason the statics are still other reproducers real value6 of my reproducer. I want For the same every music- tell you mere you will understand why some of their letters and wireless. There is about you in and mail the bane of the lover owner of a phonograph who hears about my -Music-Master-. Fill full -particulars. Ask in the remedies recently the "Music-Master" Reproducer wants the coupon below for as much virtue Circular E. to own one. for proposed as in hair'restorers. A small and Manufacturer has been produced which — ww w-« -w -m t tr\ Patentee and compact apparatus H. ELLIS P.O. Box 882 MILWAUKEE, WIS. docs 'away entirely with this trouble, at J. remodelled. Mail this Coupon Now! least in plants suitably is more important in the present Milwaukee, Wis. Nothing H ELLIS. P. O. Box 882, the wireless art Reproducer. phase of development of about the Ellis "Music-Master" Please send me full information than to dispose of the dominating erroneous ideas. With this object I shall advance a Name . few arguments based on my own observa- Address tions which prove that Hertz waves have . State even City ... little to do with the results obtained at small distances. In Fig. 13 a transmitter is shown radiat- ing space waves of considerable frequency. waves It is generally believed that these pass along the earth's surface and thus affect the receivers. I can hardly think of any- thing more improbable than this "gliding wave" theory and the conception of the Profits all Make Bis "guided wireless" which are contrary to laws of action and reaction. Why should these disturbances cling to a conductor in Battery Charging where they are counteracted by induced cur- other rents, when they can propagate in all auto storage bat- $150 to $250 Clear Profit Each Month recharging unimpeded ? The fact is that the b-volt batteries directions teries The HB 16-Battery Charger recharges 1 to 16 passing along lac per battery. radiations of the transmitter or their equivalent at once with current cost of 12c to This season means soon extinguished, Motorist pavs 75c to $1.50. Figure your profits ! the earth's surface are driven—new lords bigger batte'rv business than ever—more old ears of. the inactive zone indicated in Start after the height, Get busy now 1 Don't delay ! to have storage batteries. diagram, being some function of the those profits the wave length, the bulk of the waves travers- Money-Maker in Your Garage on Money-Back Guarantee phe- $57 Puts This ing freelv the atmosphere. Terrestrial Earnings pay tor machine. Balance in 10 monthly payments of $23 each. nomena which I have noted conclusively knowledge necessary to operate. Uses 2 or 3. Dh» se u^^"?!*. No electrical ogtteries or if complete with 2 charging panels capable of charging 1 to 8 there is no Heavistde layer, Furnished Sold on show that adjustments or expensive renewals. Big. permanent proms. each No Fin your is of no effect. It certainly HB Absolute Money Back Guarantee. Order Now—you run no nsK. it exists, it order. Do it NOW ! human race check to this ad and mail today for trial would be unfortunate if the Hobart Brothers Company, Box 5E, Troy, Ohio were thus imprisoned and forever without space. Successful Manufacturers Since 1893. power to reach out into the depths of advertisers. "Electrical Experimenter" when writing to I'o ii benefit by mentioning the 1 . — ;; ; ; ; ; ; ; ; ' May. 1919 ELECTRICAL EXPERIMENTER 63 The actions at a distance cannot he pro- portionate i" the height of the antenna and the current in the tame. I shall endeavor to make this clear by i in Fig. 14. The elevated terminal chai t" a high potential induce* an equal ami opposite charge in the earth and there are 1 1 » i - ii. in. } lines an average current | / = AQu which circulates locally and is useless except that it add- to the momen- tum. A relatively small number <>f lines / however, go ofl to great distance and t>> thesi nds a mean current of it = 4, in to -chicli is due the action iii (i distance. total a\ i ent in the antenna is thus I m —- AOn -\- 4qn and its intensity is no criterion tor the performance. The q trie efficiency of the antenna is + 4 and tin- is often a very small fraction. Dr. L W. Austin and Mr. J. I.. have made quantitative measurement- which are valuable, but far from supporting thi Hertz wave theory they are evidences in disproval of the same, as will be easily per- ceived by taking the above facts into sideration. Or. Austin's researches are es- Public Speaking 1 Learn pecially useful and instructive and regret that 1 cannot agree with him on this subject. I do not think that if his receiver was af- fected by Hertz waves he could evei estab lish such relations a- he has found, but he would likely to be reach these results if the in lessons Hertz waves were in a large part eliminated. enrr At great distance the space waves and the V Write -quick — for jP IP current waves arc of equal energy, the ^ |\ former being merely an accompanying man- particulars of this extraordinary JL A maLIA^ ifestation of the latter in accordance with the fundamental teachings of Maxwell. offer; an opportunity you will It occurs to here to ask the question me never forget if you take advantage of it. Ten lessons in effective public why have the Hertz waves been reduced introduce our from the original frequencies to those I speaking absolutely FREE to those who act promptly, to have advocated for system, in my when so course in localities where it is not already known. doing the activity of the transmitting ap- mail to become a powerful and convincing speaker—to in- paratus has been reduced a billion fold? We teach you by fluence and dominate the decisions of one man or an audience of a thousand. We I can invite any expert to perform an have trained hundreds and helped them to increase their earnings and their popu- experiment such as is illustrated in Fig. 15, larity. Learn, in your spare time at home, how to overcome "stage fright" and which shows the classical Hertz oscillator conquer fear of others; how to enlarge your vocabulary; how to develop self-con- and my grounded transmitting circuit. It fidence and the qualities of leadership ; how to RULE others by the power of your is a fact which I have demonstrated that, speech alone ; how to train your memory. Our altho we may have in the Hertz oscillator au activity thousands of times greater, the effect on the receiver is not to be compared WHAT THE COURSE New Easy Method to that of the grounded circuit. This shows that tit the transmission from an airplane TEACHES YOU. perfected and taught only by Prof. R. E. Pattison Kline, former Dean of the Public Speaking Depart- we are merely working thru a condenser, How to talk before your College of Expression, can be the capacity of which is a function of a club or lodge ment of the Columbia learned in IS minutes a day. Prof. Kline is one of logarithmic ratio between the length of the How to address board conductor and the distance from the ground. meetings the foremost authorities in the country on public speaking and mental development. Do not let this The receiver is affected in exactly the same How to propose and re- chance escape you. manner as from an ordinary transmitter, spond to toasts the only difference being that there is a cer- How to make a political tain modification of the action which can be speech predetermined from the electrical constants. Offer Limited How to tell entertaining difficult to maintain com- It is not at all stories; munication between an airplane and a Send This Free Coupon Now How to make after- - station on the ground, on the contrary , the dinner speeches; This Special Offer of TEN LESSONS FREE is feat is very easy. How to converse inter- made strictly for advertising purposes and will be To mention another experiment in sup- estingly ; withdrawn without notice. Write now, before it ex- port of my view, I may refer to Fig. 16 in to write better pires, and receive full particulars with enrollment which two grounded circuits are shown How blank by return mail. No obligations of any kind. excited by oscillations of the Hertzian order. letters to sell more goods Just tear off and mail this free coupon—or a postal It will be found that the antennas can be put How will do. out of paralleli-m without noticeable change How to train your in the action on the receiver, this provin memory to enlarge your that it is due to currents propagated thru How the ground and not to space waves. vocabulary FREE LESSONS COUPON Particularly significant are the results ob- How to develop self- tained in cases illustrated in Figures 17 and confidence; North American Institute, win- 18. In the former an obstacle is shown in How to acquire a 7415 Manhattan Bldg., Oiicago the path of the waves but unless the re- ning personality ceiver is within the effective electrostatic How to strengthen your I am interested in your course in Effective Public influence of the mountain range, the sig will power and ambi- Speaking and your offer of ten lessons free. Please are not appreciably weakened by the p tion; send full particulars. It is understood that this request ence of the latter, because the currents pass How to become a clear, places me under no obligation of any kind. under it and excite the circuit in the - accurate thinker; way as if it were attached to an energizi d How to develop your wire. If, as in Fig. 18, a second ramre hap- power of concentra- pens to be beyond the receiver, it could only tion; strengthen the Hertz wave effect by reflec- How to be the master tion, but as a matter of fact it detracts of any situation. (Continued on page 87) You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. w 64 ELECTRICAL EXPERIMENTER May, 1919 Pour Red,Whife ^Blue ly Iimveinittnoinu {Continued 17 frofh a Glass of Wafer fi om tage ) You can mystify your friends with puzzling lamp there. It was the exact spot which I life had been squandered. But it did not ch«mical tricks; write secret letters with invisible ink; make your own magic writing had originally chosen. take long before I recognized that it was paper, and your own blue ink or Ink powder. Writ© with water and have it turn blue. Yon So it went day after day with variations, the best thing I could have done. Within can pour seemingly plain water Into three glassesand have it turn red In one, whits In but I was determined to achieve at what- a few weeks I had won Edison's confidence atherand blue in the third. Send twenty- i cants in stamps and get your outfit by ever cost and in the end my efforts were and it came about in this way. il, postpaid. If you send right away, we 1 willenteryourname to receive a copy of Th« rewarded. By the spring of 1884 all the The S. S. Oregon, the fastest passenger " Chemcraft Chemist. It's an iir|CIWum.„uri Interesting magazine for boys. E*H? differences were adjusted, the plant formal- steamer at that'time, had both of its lighting egular "CHEMCRAFT" Out- Junior tits at SI. 60, $3.00 and $5.00. QCa ly accepted, and I returned to Paris with machines disabled and its sailing was de- THE PORTER CHEMICAL CO., aC OC. Arcade Building Hagerstown.Md. Poatp'd pleasing anticipations. One of the admin- layed. As the superstructure had been built istrators had promised me a liberal compen- after their installation it was impossible to Build Your Own PHONOGRAPH, sation in case I succeeded, as well as a fair remove them from the hold. The predica- It's Easy With Our Help SAVE consideration of the improvements I had ment was a serious one and Edison was A few hours Interesting work made in their dynamos and I hoped to real- much annoyed. In the evening I took the saves many dollars and gives OVER you a machine exactly to suit ize a substantial sum. There were three necessary instruments with me and went your ideals. We furnish motors, HALF administrators I shall designate as aboard the vessel I for tone arms, case material, blue whom where stayed the prints and full instructions. A, B and C for convenience. When I called night. The dynamos were in b'ad condition, Plays any record. You can make fine profit building phonographs on A he told me that B had the say. This having several short-circuits and breaks, but for your friends. gentleman thought that only C could decide with the assistance of the crew I succeeded Write Today for Our Free Blue Frint Offer. Agents and the latter was quite sure that A alone in putting them in good shape. At five wanted for our ready built had the to act. After several laps o'clock in the morning, passing along Choral eons. power when of this circulus wciostis, it dawned upon me Fifth Avenue on my way to the shop. I met Choraleon Phonograph Co- that my reward was a castle in Spain. The Edison with Batchellor and a few others 705 Monger Bid;., Elkharl, Ind- utter failure of my attempts to raise capital as they were returning home to retire. for development was another disappoint- "Here is our Parisian running around at Patented ZIP-ZIP Sept. 3rd. 1918 ment and when Mr. Batchellor prest me to night," he said. When I told him that I The Greatest 60 Ct. Article on the Market. of redesigning coming the Shipped right from the factory the same go to America with a view was from Oregon and had re- day we receive your order. The Prong is I paired both made of beautiful metal; never break or the Edison machines, determined to try machines, he looked at me in wear out ; scientifically made and in silence without st workmanship. The rubbers my fortunes the Land of Golden Prom- and walked away another elastic and lasting, wit' I plenty of pep and force. Zip- ise. But the chance was nearly mist. word. But when he had gone some dis- Zip, complete, only 50c pre* tance I heard : ?.ala. Be sure the name Zip- liquefied my modest assets, secured accom- him remark "Batchellor, this ip and our address appear \ modations and found myself at the railroad is a d n good man," and from that time on the article you buy. Order < — on from ua or any Sporting Goods pulling I full freedom in directing the Storein your city. SendStamps, station as the train was out. At had work. Coin or Money Order, I discovered that For nearly a year regular hours AUTOMATIC RUBBER CO. that moment my money my were COLUMBIA, S. C. and tickets were gone. What to do was from 10.30 A. M. until 5 o'clock the next the question. Hercules had plenty of time for to deliberate but I had to decide while run- .ning the train feel- NEW alongside with opposite MY BOOK ONE DRAWING ings surging in my brain like condenser ^ "Muscular Development" ^ U lustra tors—-CartoonistsCartoonists — Com- i- -. «— oscillations. Resolve, helped by dexterity, mercial Artists make big money will tell you how to get a wonderful muscular Learn NOW at home in spare won out in the nick of time and upon pass- development like mine, perfect health, abun- time by our new instruction of vitality and great 50 method. Handsome booklet ing thru the usual experiences, as trivial as dance strength as I have. free explainaeverything. Write The results of my system for it today. Get our Special unpleasant, I managed to embark for New are shown on my own per- Free Outfit offer. son and that is recom- PAID Washington School of Art, Inc. York with the remnants of my belongings, 14U7Hdt.,N.W.VVabhiugtou,D.C. mendation enough. To give some poems and articles I had written, and every one the opportunity to profit by what I have a package of calculations relating to solu- learned, I will mail ray tions of an unsolvable integral and to my book, for a limited time NATIONAL DENTA L only, on receipt of flying machine. During the voyage I sat TRADE Q SCHOOL most of the time at the stern of the ship Stamps 806 8. Wabash Ave.. Chicago, III. LEARN MECHANICAL DENTISTRY—DEMAND UNLIMITED watching for an opportunity to save some- 10c or Coin A paying professional trade: You will be a trained dental body from a watery grave, without the mechanic and receive our diploma when competent. Stu- This wonderful book dents I given advantage of thoroughly up to date laboratory, slightest thought of danger. Later when will help you. It is pro- and services of graduate Dental Surgeons on practical cases. had absorbed some of the practical Ameri- fusely illustrated and No effort spared to place graduates advantage ousLv. No age contains pictures of many limit. Day or Evening. Individual instruction. No educa- can sense I shivered at the recollection and of the world's strongest tioral requirements. No book or home study. Easy terms. men whom I have trained. Highest references. those marvelled at my former folly. Especially attractive proposition to EARLE E LIEDfcRMAN Send for it to-day. Right Who write at once for catalog H. ' Tesla in America Why not look ai bealtby and be n " n while it is on your as strong as 1 am? tuind. You Can RENT I wish that I could put in words my first EARLE LIEDERMAN. Dept. 208, 203 Broadway. N. Y This Phongraph impressions of this country In the Arabian Tales I read how genii transported people on our new plan! $10 puts this Young's Mechanics' Utility Superior Phonograph in your home on 30 into a land of dreams to live thru delightful Days' Trial! Plays all makes of disc records. adventures. My case was just the reverse. MOTOR GRINDER Cabinet size, 47 ins. high. Rental applies on A Time-Saver and Money-Maker for $62.50. for purchase. $125 Value Write The genii had carried me from a world of For Shop, Factory, Garage or Home details of greatest phonograph bargain ever Attach to any electric light socket Offered. Offer Limited. Write Today. dreams into one of realities. What I had end yoQ have a power unit which will do grinding or all descriptions as YOUNG'S SUPERIOR PHONOGRAPH left was beautiful, artistic and fascinating well as drive small machin- 62 W. Madison St. Dept. U. Chicago. Ill ery. Can be furnished with in every way; what I saw here was ma- chuck and buff for buffing. me B—Complete with 4 in . by chined, rough and unattractive. A burly „,.e-half in. Emery Wheel, . MOVING PICTURE BUSINESS Order today. twirling stick $15.50. policeman was his which PACINE UNIVERSAL MOTOR CO. Jackson Blvd. Chicago, hi. JSmall Capital Starts You looked to me as big as a log. I approached 53 W. him politely with the request to direct me. on our easy payment plan. Begin "Six blocks down, then to the left," he said, FRENCH WIRELESS now and get your share. We sell everything. Write today. with murder in his eyes. "Is this America?'' FROG made of steel i with large clicker inside, how earn telegraphy. you to Atlas Moving Picture Co. I asked myself in painful surprise. "It is a used to learn 10. S25=2ro*50=sperday ORE\T FUX. SEND — — „_, pept. 49 53 8 S. Dearborn St. .Chicago century behind Europe in civilization." YOUR FRIENDS WIRELESS SENT complete with ' quickly cured, if you When I went abroad in 1889—five years MESSAGES. Yma can be code, and to make a big bundle book. having elapsed since my arrival here—I be- we will send a Ford joke Parlor games, etc.. all tor lue came convinced that it was more than one Dept. 72, American Toy Co., Lowell, Ma»».,U.S.A. STAMMER hundred years AHEAD of Europe and Send 10 cents coin or stamps for 70-page book on Stam. nothing has happened to this day to change Anering and Stuttering, "Its Cauwand Core." It tells how I ^m cured myself after stammering for 20 years. my opinion. ^5 Benjamin N. Bogue, 4 Bogie Building. IpdiawpolU 75 Tesla Meets Edison A WONDERFUL NEW TO ' INDEX The meeting with Edison a memor- INVENTION The Q. 8. Target was to 30 feet, Pistol shoots shot 100 feet, wooden arrows 20 able event in my life. I was amazed. at this with Burpiisimr power and accuracy. Boya go wild over ELECTRICAL EXPERIMENTER It. grown people find itmost interesting. Send 10c. (sil- wonderful man who, without early advan- ver) for sample, terms, etc. Our Q. S. Special. 26c. , for the older boy and grown people. Send 3c. extra for scientific FOR VOLUME 1, 2, 3, 4, 5 ?nstage and packing on single order. (Agents wanted.) tages and training, had accom- PISTOL - - DetinSOft, H, T. HE Q. S. NOVELTY CO., plished so much. I had studied a dozen Po8t aid languages, delved in literature and art, and Price J P "earn money had spent my best years in libraries reading OC» Stamping Names on Key Tags. SCft all sorts of stuff that fell into my hands, EXPERIMENTER PUBLISHING CO. Either sex. Spare t\m*. Some make *3\3 Send 25c for Tag with your name on and instruc- from Newton's "Princi[>ia" to the novels of Book Dept. 231 Fulton St., N.Y. ttona. ReturnedlfTequired. Exp. Key Tag Co.. Cohoes. N. Y. Paul de Kock, and felt that most of my You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. T 1 May, 1919 ELECTRICAL EXPERIMENTER 63 morning without a day's exception. Edison ;aid to me: "I have had many hard-work- a5xa=sg£^ggs ing assistants but you take the cake." Dur- ing tins period I designed twentj I % different types of standard machines with Dozt t Commit A Crime .vlmrl lores anil of unit'orm pattern which replaced the >'M oir-s. The Manager had Against The Woman You Love promised me fifty thousand dollars on the completion of this task but it turned . - .. v, to be a practical joke. This gave me a AMnI r r ! II ?»r the No . .ii commit, purt, painful and I tin position. shock resigned Irustli Immediately thereafter some people ap- KIT t proached me with the proposal of forming ii. -r whole future i an arc light company under my name, to t.. belp li'-r u ^ mi ; ! fslthh u hi i which 1 agreed. Here finally was an op- it the rnatttr a lidt, fOU . i r v lit, portunity to develop the motor, but when |U i girl Im- potent, sickly; grouchy with ached the subject to my new ass.,, I "\'<>, arc lamp. they said: we want the I \\ r don't care for this alternating current : ...-. ir do! for your own • her marrl- III Off, If of yours." In 1886 my system of arc light- v nil .m* onlj in. m. M Ith ) OUT n ing was perfected and adopted for factory Hubby, youi blood 11 if as a r your ooodltlon, and municipal 1 ii^Vi t invr. and I was free, hut with no other possession than a beautifully engraved certificate of stock of hypothetical She Thinks You Are a Man value. Then followed a period of stro in the new medium for which I Was not sin- trusts, Admires snd lores whal ihe THINKS real man, mentally, moral! Icaily, fitted, hut the reward came in the end and She beltei i in April, 1887, the Tesla Electric Company man who can look anj other man In was organized, providing a laboratory and our own with him; who Is able t" protect her who can make hit way in the facilities. The motors I built there were nd give her the comforts she has s right to as> exactly as I had imagined them. I ma 1 in her husband; and finally who will ultimately attempt to improve the design, but merely make her the mother « use. I had already noted in my demonstra- ay that has brought i tions before the American Institution of hope snd r ol Using to thousand-, ol other men; li will ihow you FREE CONS ULTATION COUPON Electrical Engineers that several times the how to make yourself FIT to live; KIT to «>r. if .ire man i Mr. Newark Picas** readjustment. marry; you [done] BtrongforL N. J.— tune was lost, necessitating will belp rou become the father <•( i Bond me your book, '-promotion and con- happy, laughing children who will ' SERVATION OF HEALTH. and did not yet foresee, what I discovered STRENGTH AND i ir wife sa Ions a> you lire. MENTAL ENERGY. long afterwards, a means of operating a JOB WANT THAT BOOS. tampa. I hare marl before the subject in which I am inter. machine of this kind at a speed constant to ..Colds . Flat vary more than a Do Your Part Now Feet Heartweakness such a degree as not to . .Catarrh ..S'omach Poor Asth Disorders small fraction of one revolution between DO TOTJB P-irt and I'M 00 MINK— M guarantee it. Kill mil ami send me the . Obesity . .Constipation Skin Disorders the extremes of load. with three % . .Headache . .Biliousness Despondency . king n tlu> fr..- iNHik, "Promotion Thinness . Torpid Liver . Round The Invention of the Tesla Coil and Conservation of Health, Strength and . Rupture . . Indigestion Shoulders Mental Energy." ami I'll lend you with . Lumbago ..Nervousness .Lung Troubles it. without charge, helpful, perawal in- . Neuritis . .Poor Memory .Increased it ap- many other considerations . From formation on Lit are .Neuralgia . . Rheumatism Height peared desirable to invent a simpler device troubling you DON'T DELAY A . Flat Chest ..Youthful .Stoop ir pari now , . Deformity Errors Shoulders for the production of electric oscillati (describe) ..Vital Losses . Muscular exposed the theory . .Insomnia . . Impotency Development In 185b Lord Kelvin had ..Short Wind ..Gastrin's of the condenser discharge, but no practical LIONEL STRONGFORT application of that important knowledge was made. I saw the possibilities and un- Health and Strength dertook the development of induction ap- Specialist paratus on this principle. My progress was 883 Strongfort Institute Newark, N. J. so rapid as to enable me to exhibit at my lecture in 1891 a coil giving sparks of five inches. On that occasion I frankly told the (Continued on page 89) writing to gjvertuert. You benefit by mentioning the "Electrical Experiment*" when — 66 ELECTRICAL EXPERIMENTER May, 1919 FUTURE RAPID TRANSIT AN EASY WAY TO (Continued from page 7) an airplane and provided with planes or MAKE MONEY ,s This provision of planes on either on a small salary. Be independent. Go in the tire re- wings. pairing business. One man says "I made $60.00 the first side of the car renders it possible to modify day." Others average $200 to $500 a month. Very little capital needed. Jobs plentiful. Every motorist a pos- DO Your their angle of incidence, to relieve, the sup- sible customer. No experience needed. We teach you. Own PLUMBING porting rail of larger part of the weight a Tire AND HEATING at low cost of the vehicle. HaLSH Repair Outfit Send for our big inst motive The aerial monofiier, as our artist has Improved Wrapped Tread Method Used by Tire Manufacturers 256 page well-bound Handy- here depicted, may be propelled by means Man Book Catalog. Every Does as good work as the big high of one or more propellers placed either at priced vulcanizing outfits. A boy H o m e Owner, Contractor, the car or at both ends, and in can use it. It's the only vulcanizer Electrician, Farmer, Factory one end of that has Automatic Heat Control, and electrically driven, can't undercure or overcure a tire. Manager, etc., needs it. Shows any case these could be Requires no watching or regulating. over 10,000 Fixtures and Sup- the current necessary for operating the plies in plumbing and heating electric motors being taken thru appropri- FREE Rook at wholesale. Shows how to ate contact shoes or brushes, resting in "How to Open a Tire Repair Shop." save skilled labor, hard work It tells how to make big money. rails fixt and unnecessary material by contact with insulated conducting Don't delay. Write quick. upon which the monorail to the frame-work C. A. SHALER CO. OUR NEW of the mono- is supported. The end view 2204 Fourth St. Wlnpon, Wisconsin Cut-to-fit-Method flier shows clearly the arrangement of the two third rails, one on either side of the -IE MIDGET SLIDE RULE TTiis wonderful book helps you select and install the monorail, constructed so that they may also proper Plumbing. Water Supply System, Hot Air, has many exclusive features. It Water or Steam Plant. Besides being our Wholesale serve to insure the maintenance of the car v. ill handle three facturs at one Catalog it setting and has a Log-Log Scale, has many practical in the proper vertical position, by pre- plans, diagrams, sketches, ele- Polyphase or Inverted Scale, Ad- vations, etc., showing how to venting any lateral displacement thereof. dition and Subtraction Scale. Square Root Scale and Binary do the work this newer, cut- the car in to-flt way. Any handy man For the 'purpose of maintaining Scale. It will add and suhiract with a few tools can easily do the proper vertical position by virtue of (fractions and give decimal equiv- his own installing with the alents, multiply and divide frac- aid of this the third rails just mentioned, there are tions and mixed numbers. It will Big Handy -Man also give the Logarithms of Book provided two series of wheels inside the car. Numbers and the Sines, Tangents. We have spared no as the end view indicates, one set on Cosines and Cotangents of all effort and have gone to a angles. An instruction book, "The great expense t" compile either side of the monorail structure. From Slide Rule Manual."' 16 pages. 12 illustrations, is sent with each rule. this valuable book. With Length of Logarithmic Scale, 12 inches. Diameter of rule, 4 inches. economy still a national one end of the car to the other, the slot, Body of rule made of 24 Ga. sterl. transparent celluloid indicators. printed in black on a white coating, figures large and easily necessity, it would be un- Graduation 3 as it might be called, slightly expands so read. Price, sent postage paid wilh instructions. $1.00. Send for free patriotic to send this ex- descriptive circulars. Your money back if you are not satisfied. pensive £} book broadcast that the car can negotiate curved sections GILSON SLIDE RULE CO., Niles. Mich. to non-interested parties. Therefore, we request a of rails, which it could not do if the slot temporary deposit for each running thru the car from front to rear Says the Master Mechanic. The Greb copy of 25c which we re- Automatic Grip Puller is a One-Man fund on first order, or were made perfectly straight. The car is Puller tiuick-acting, strong and sim- we send our — Bargain Bul- provided with electric lights and the usual ple in the extreme. May be locked in letin Free. Address Today any desired position. A combination protective features, such as electric braking of two or three arms. Heavy Duty HARDIN-LAVIN COMPANY 1" electric in weather, sig- Size capacity to IS"—Junior size 40 Years At means, fans warm capacity 1" to 7". Two sets of jaws 4510-20 Cottage Grove Ave., Chicago nal lights, etc. The motorman, whose cab furnished with each size. $500,000 plants behind our guarantee ou is placed in the forward part of the car, Ten Days' Trial J'.i?r .S jobber not have them we will send yoa full the electric propeller does has control of Dne. Try it tea days. If not satisfactory, return to us and we will refund your money motors, and he can also change the angle We also make the GREB RlM TNOl. of the planes, on either side of the mono- THE GREB CO., 230 State Street, BOSTON IN FOUR flier, so as to cause it to practically float I Earned $2200 MONTHS in the air when it is under full headway, the monorail passing thru its center merely acting as a guide rail along which it flies. Electric heaters could be used in the cold weather, and for heating coffee and cooking light meals, etc., in the buffet lunch on Swing 4 in., 11 in. between centers, 17 in. total Shippingweightl31b9. Bed , board, electric stoves would be available. length. of lathe ia machined, \Vorkmanship flrst- 1 class. Equipped with wooa turning chuck, 1 In general the monoflier is ovoid in form, Can be 6tted with 3 in. face plate and drilf chuck u _ equipment. one today. Price $5.00 caabl thus following the latest practise in the special Order is 1 nnHis £k% STPHEB MFQ. CO., DEPT. C TOLEDO, OHIO \ * Richard A. design of dirigible airships, so that it will Oldham. He earned $2200.00 encounter the minimum of resistance from in four months with a Hay the air during its displacement. Such a CONVERT YOUR BICYCLE INTO wood Tire Repairing outfit For craft should be easily able to attain a speed -p 20 years he was telegraph operator on the of 175 to 200 miles an hour and higher, as A MOTOR-CYCLE «fc i. Illinois Central Railway. He is now 58 years when it has attained its highest velocity and Best hill climber. Most reliable. answered advertisement—quit More STEFFEY'S in use than old. He my the planes are properly elevated, the craft his job—bought a plant and opened a busi- all others. LOWEST PRICES. just "I have made more will be practically floating in the air, without ness. He wrote me Cash or instalments. Send Stamp for circular. in eight months than years as operator." 2H encountering any retarding friction from Agtnis wanted. There are now 500 stations where tire re- engagement with the monorail, excepting pairing is neglected. Steffey Mfg. Co., Dept. E, 5025 Brown St., Phila.. Pa. when passing around curves. Even here I Must Have 500 Men the friction which would normally be en- To Fill These Positions countered might be reduced considerably if SMALL ENGINES I have a Big interesting Book to send you. not entirely obviated by the provision of a Perfected Gasoline Engines It tells all about tires—gives for Farm proper air rudder at the rear of the car. Vz. 1 and \Vz h. p.— inside figures and profit Send and Shop use. Price. $27.50 for it! What Oldham and others} When the car had reached the end of its and up. Also, are doing You can do. 52500.00 to WASHING MACHINES run, its peculiar etc., $4,000.00 per year is conservative. owing to ovoid shape, We ship on trial. Send for Like Mr. Oldham— One machine it would have to be reversed in position Booklet and Special Offer. will start you. Then open a shop. SIEVERKROPP ENGINE CO. all around you. Pot before starting else Wis. You can seebusiness back, or sent back to Di — 1 9th St. Racine, out a Haywood Sign and business will its destination by parallel monorail cometoyou. Now g^t started. Send for a sys- STARTER for FORD CARS the Big: Book and start making money. tem, which would undoubtedly be the usual Pres. M. HAYWOOD, practise, much in the manner shown in the Tire & Equipment Co. Haywood accompanying view. Undoubtedly in the SAVE 25% to 60% 1209 Capitol Ave. Indianapolis, Ind. years to come, when such highly congested on sliehtly used localities as Xew York City have become GRAFLEX-KODAKS more and more built up with towering office Cameras and Lenses of every description. Equal to new. Save money. Write now for structures, with a dailv working population Free Bargain Book and Catalog 15,000.000 listint? hiimlri'iis of money-savins' bargains in of say 12.000,000 to "people, and sliehtly used aid new cameras and supplies. All the goods sold on 10 days' Free Trial. M.nevback subways and street elevated lines have if not satisfied. You take no chances dealing 1 Jt^ I teach you per* i become crowded to the limit of endurance, with us. We have been in the photographic i Ifi Write now. Sonally, b7 mail, n a short f business over years. time. Oldest and. largest Sc then it seems that such a system as this CENTRAL CAMERA CO.. Depl. 175, 124 S. Wabash Ate, Chicago Big Cell, work interesting. Yui EARN SI8 TO $45 A WEEK '' should serve a very useful purpose indeed. Fritzner, Minn., wrote. ' "Did i°b after fi If got "JIO, profit $7.05 Crawford such a system as here illustrated eon, t INSYDE Inner Armor 'says: "Earned $2C100.00 while taking course, TYRES literature, samples, guarantee; all FREE. were properly constructed and designed, it for Auto Tirea. Doable mileaire. prevent blow- i outs and punctures. Easily applied in any tire. DETROIT SCHOOL OP LETTERING would not only serve as a fine piece of in- I Thousands aold. Details free. Agenta wanted. Established 1899. 6S3 D. S. ofL. Bldg.. DETROIT. MICH. Amcr.Aoceaaof rba Co-.Dept.53 Cincinnati dustrial engineering, but it would also give You benefit by mentioning the "Electrical Experimenter'* when writing to advertisers. May. 1919 ELECTRICAL EXPERIMENTER 67 high speed traveling facilii ubur banites, who have to travel ten t.. t • miles every night and m ing to and from business, such ^ those who live in the rapidly developing Westchi itei ' ount; tion, where undoubtedly man) hundred thousand "i New York's future popul will reside, as well as those who will i tlicir homes on Long Island. As the illustration -.hows, the monoflier i-. divided into several Boors, and if de- sired, each flooi maj bi Mil. divided into compartments. The lower floor is prefer- ablj reserved for luggage freight and in. ul. while the upper floor may be very well utilized tor the electric mol .ititiK llie propellers and lifting planes. Stair- ways lead from the lower flnorv to the up- Is Require per floor or flo tiding upon the site of the car. The main frame-work of the car is composed of rolled steel sections, and rest lack Saw Blades the of the structure including the doors and outer covering is of aluminum, the If vou want to cut structural steel or brass pipe effi- seams being electrically welded so a- to ciently, you need a different hack saw than foi present a perfectly smooth surfaci on the iron or machine steel, and you certainly can't work entire exterior in order to minimize the as coarse a blade in a light machine as in a heavy resistance to the air. The windows, which one. To try to do everything with the same blade is afford an excellent view to the passengers simply to do most of it inefficiently. as they >-kim along over the tops of the skyscrapers far above the city and the sur- rounding country, are fitted "with the new unbreakable glass. Also the outer contour Hock Sows of the windows and doors are made so as StQVPZtt to fit very tightly and to preserve an even will'help you select do the most work with the least effort and Our Hack Saw Chart surface both vertically and horizontally kind of work, each one is the proper blade for any for the purposes in the time because aforementioned. it. Our Service made to meet the exact requirements of and vou can depend upon Some other novel solve your cut- features involved in different metals in different powered ma- Department will help you design efficiency the of this aerial monoflier, which chines. ting problems and increase the seem to possess great practicability are as of your citting-off department. follows : The inventor points out that in order to impart greater stability to the Write us today. Ask for Catalog No. 21 LE. car. its longitudinal axis should preferably €>Storrett# be located below the top of the monorail. Hock Sow Chort In other words, the greater part of the -'-Jv ™ weight should be distributed on a line below THE L S. STARRETT COMPANY A ^_r=^=. =. the monorail level, which line is at a point The World's Greatest Toolmakers. about one-third "I the height of the car from 1 - Manufacturers of Hack Saws Unexcelled. ir^rfr a the top of the same. The large wheels in Mtn* — the interior slot —— ... >• ** — of the car, which rest on ATHOL, MASS. the upper or monorail, are heavily flanged. S6- 1 •In order to provide against the possibility ==LI sis. - s; ^ k of the vehicle leaving the track vertically NEW YORK LONDON CHICAGO = m _ . _ *™ • under the influence of the air pressure be- 1 neath its wings, the lower portion of the . third rail rollers may be given a circular WLLinUmtO. ArM.Ktu.D-lA. flange, which in the case under considera- tion would bear against the lower flange of these rails, and thus serve to maintain the car in contact with the rails. The car could be made longer as desired, but. of course, it could not be made too long, or Learn Telegraphy-Wireless otherwise it would be impossible to turn 1 curves, unless they had very in time long radii. Right In Your Own Home, your spare ^ Most probably the reader has Remarkable opportunities are offered experienced wire- become ; interested in the general working principles less operators and telegraphers. The demand is greater than of such an aerial monoflier system, par- the supply—steady positions at increased pay and rapid ticularly in the probable arrangement of the stations, which could be of several advancement are assured. types, as our illustration herewith shows. DEPENDABLE Some of the stations could be erected on Combination A*v M-C**. the roofs of tall buildings where these were v-Hltllt of appropriate height for the purpose, and Wireless -Telegraphy in some will soon make you an accomplished operator. cases where the railway past di- . mctiic spiciimis Teaches Light and Sound Signals, both Radio rectly thru the tower of the skyscraper, the and Morse. Outfit consists of exceptionally tine station could be built in the "hole in the i tph Key, Buzzer, i Binding rOBta, Lamp. wall", as it might be called. Each station Lamp Socket and Control Switch - all mounted on a highly fin- could be designed in several ways— for in- ished base. Two outfits can be $o-oo stance, it might in some cases be provided operated at considerable with one platform, and the passengers on apart for sending and receiving practice. 3 the monoflier in this case would have to descend from the upper to the lower floors by means of the stairways provided in the car, before reaching the station. The sta- This Same $Q.50 tion platforms could be enclosed and pro- Outfit S vided with sliding doors, so as to be draft- Without Lamp *" proof in the cold weather, and high speed express elevators would carry the passen- Order to-day. Or your dealer can secure it for you. De<- rircular and catalog i E celebrated Knap] U ad Electrical gers from the aerial railway station to the Specialties from 10c up nailed tree on request, KNAPP LEADER street, or by taking a local elevator, they Radiates real power-plant could alight on any floor of the building- Knapp Electric & Novelty Co. da and all of which seems very Price. Complete. good from a 523 West 51st Street New York City $3.50 strictly engineer point of view. Vou benefit fry mentioning th ai Exfc-intcnter" when writing to advertisers. 68 ELECTRICAL EXPERIMENTER May, 1919 LOCATING ENEMY GUNS BY Magic-Like Relict FLASH AND SOUND for {Continued from page 14) Asthma As the name suggests, "sound ranging" is Barbers' Itch Boils based for its operation on the transmission Blackheads of sound, either thru the air or thru the Bunions Callous earth, whenever a gun is fired. Some of Catarrh this work is performed in conjunction witli Chilblains Colds the flash spotters, for by observing the flash Corns sec- Constipation of a distant gun, and then counting the Dandruff onds on a split-second watch until the sound Deafness Earache is heard, the distance at which the gun is Eczema located may be accurately computed, as the Eye Disease Falling Hair velocity of sound thru air is about 1,100 Hay Fever Headache feet a second. The velocity of light is prac- Goitre tically instantaneous, or 186,000 miles per Insomnia Lumbago second, and secondly it serves very accu- Nervousness rately to consider the flash of the gun as Neuralgia Neuritis the starting point of the onward journey Obesity Pains of the sound wave. The accurate locating Paralysis of any gun is accomplished by having two Piles Pimples observers take telescopic or other sightings Pyorrhea on the gun, noting the distance between Rheumatism and Skin Diseases the tw-o observers and the angles as mea- Sore Throat Sprains sured on their respective instruments. Thus Tonsilitis it is a simple matter to solve accurately by Whooping Cough triangulation the definite location of the enemy cannon. This is only one side of "sound ranging" science, however, as applied to modern ar- tillery tactics, and the scientists and engi- neers connected with the work of the artil- - lery , particularly the locating of enemy gun positions, early in the war -worked out a high- in own home you can have wonder- NOW your ly sensitive sound detecting apparatus which ful Violet-Ray treatments exactly as are picked up the sound of enemy guns, even at given by eminent physicians and beauty the specialists throughout the country. Now you a great distance, as transmitted thru can rid yourself of headaches, catarrh, consti- earth. For this purpose detectaphones and pation, eczema, insomnia, lumbago, nervous- Audion amplifiers prove highly efficacious. ness. Relieve your pain from neuritis, rheum- Enemy guns 15 miles distant were accu- atism, and other disturbances. Multiply your rately located by this means, the same trian- vitalize your nerves, double or bodily health, gulation maneuvers as previously outlined treble your energy by using Violet-Rays. Sleep being followed. and usually three ob- better, increase your strength, and improve Two your appetite and digestion. Soothe your nerves, servation (sound-detecting) points being reduce or increase your flesh. Tone and employed, advantage being taken of the strengthen the entire system. Beautify your values as given by the velocity of sound complexion. All with Violet Rays! when transmitted thru the earth, and also by the difference of time at which these sounds arrive at different sound-detecting stations. Used in conjunction with the reg- NotaVibrator ular angular measurements, the locating of The Violetta is not a Vibrator. It is not a machine enemy guns became as simple to General that contracts the muscles—it does not shock, it does Pershing's artillerymen as weighing out a not pound the muscles— it is absolutely painless. Vlnlet-Rays administered by the Violetta are wonderful pound of butter would be to a groceryman. even tor Infante Relieve pain and suffering in every part of the body simple tests prove that Violet-Rays pass com- pletely through every part of the body, stimulating every cell IN remedial form. EXPERIMENTS RADIO ami organ, it la electricity in its highest ACTIVITY. Part III. Read What Physicians and Users Say (Continued from pag 35) - noticed Trixie Friganza, well known K. L. Allen. D. C. 205 Boone Frank Borzone, Seattle.Wash., radio activity actress says "Cheerfully will I National Building, Boone, says: "I purchased the VIO- that radium induced an add my praise for Violetta. Iowa, says: I have had very LETTA for my wife who was activity into substances It's the best 'pain chaser' and good results with the appli- suffering from an acute attack placed in its vicinity. the very 'soother' I've had the good cation of High Frequency of Sciatica. From This induced activity fortune to find. It's Current in cases of Paralysis. first treatment it induced WON- w-as found to consist of DERFUL. It cured my Rheumatism and Neuritis and peaceful rest and she is an active deposit brother of neuritis. As for think it a great help in drug- entirely well now." the disinteg- myself I use it for facial treat- less healing." formed by rating radium. In the ments and general massage. Dr. Daniels, Lisbon, North I cannot say too much for it." Dakota, says: "Have used the spinthariscope the lens portion found to Dr. Bert H. Rice, of Vinton, VIOLETTA in such cases as was Iowa, says: "I have good re- Goitre, Bronchitis, Pleurisy, assume this induced ac- Radiograph Taken by the Author, sults with the Violetta High Neuritis, Neuralgia, and Lum- tivity because of its bago, and find it very benefi- Using An E. I. Co. Frequency Instrument in all proximity to the active Spinthariscope cial. In fact. I would not be cases of neuralgia. Almost substance. This may with Lens Re- without it in my office." instant relief in Facial Neu- be easily shown by use moved. The Fig- ralgia." ure "U" Was Cut of the electroscope, de- from Brass Sheet. scribed in the first arti- cle. Using the spinthariscope in the posses- sion of the author, the following results FrTeTookTupoVX -^ FREE were obtained : —empty, the electroscope dis- BOOK charged in 700 seconds; the lens portion BLEADON-DUN CO. Dept- 2D, ^* Write today without fail. Mail coupon or just a postcard. Let us was then removed and introduced into the 32-page beautifully illustrated free book, describ- 11 So Desolaines St Chicago, 111. %, send you our electroscope. This timejt only required 320 nig the Violetta in detail. Read the amazing phenomena pro- ^ seconds. This conclusively shows that Please send me your free book ^ duced by Violet-Ray High Frequency current. Why it and 10 Days Trial offer on ^ produces stimulation and sedation. How to give spinal radium induces an activity into other objects Violetta, to treat various ail- Violetta Violet-Ray Machine. + treatments with the how exposed to its radiations. This induced ac- * ments, including nervous troubles, rheumatism, obesity, ^» hay-fever, skin treatments, facial treatments. Mail cou- tivity, however, soon decays. Other uses Name •* pon or postal right now before you turn this page. for the spinthariscope will suggest them- selves to the reader, but in any case he will V BLEADON-DUN CO. certainly never regret purchasing or else \ Dept. 2D making one. City ^ 11 So. Desplaines Street Chicago, 111. (To be continued) mentioning the "Electrical Experimenter" when wt \ting to advertisers. 1 May. 1919 ELECTRICAL EXPERIMENTER 69 IN SLANG "Slickest SCIENCE THE SPECKS IN SPACE Trick onlinufd from / You hundred n Ever ptillion. Tin weigh) oi the >mi is . lillicm." Saw" "Then the Sim weighs twenty-threi lion, forty nonillion grains," put in Punk. MINUTR V JV "Approximately," returned Stokes, with ONEIt's a rou^Hter «4v^ nil smile. — with sturdy, roomy 1 1. f >i wagon -bed, big enough to haul . yi hi ihiuk that the lines of er, * e, Ice, wood, and tools, ' an' every- electricity, that are radiated from the - or tt.)!^." The next minute It's the niftiest ! Sun act iln- Earth turning on i<> speedster you ever saw — a real coaster, upon I UILT for coasting, with stream-line body, diurnal axi^ and traveling in its long and lean like a greyhound. The around the Sun in the same manner as the Auto-Wheel Convertible Roadster a dynamo?" enquired Bill I N an is I At least iln like Its older brother, the Auto-Wheel Coaster, is "Thai possible, suppose. I, nit v.ry much lil.oun nutomobile^with ovalapokcs. radiation: from the Sun are, mon roller- bvurinirs. and steel axles. Tires of steel, to give long, hard service. likely, responsible for <>ur electrical phi FREE-FELT PENNANT nomena and along with it —but we do not to every boy who sends u» the names of three coaster ani- wigon dealer*, mentioning which ono hud know to what extent tho plant and Auto-Wheel. Oar color catalog goes with pennant. mal life, BUFFALO SLED COMPANY, "Schih- have one theory, some have an- 1*3 Schenck Street, N. TONAWANUA, N. Y. other, but I would ii"t in surprised al some Ftm Cap to #• * In CiuKntir mcmltrr of th« mt that "ill do to our dope what Coaotcr t'lub. Preston, Writ*. f w did to the old 'Seven Stars' idea. (int. From the thought thai our planel was the center (natural to the more or less e "I Can Succeed!" i al Man) the universe, the idea that of to "What other men have done with the the Sun was IT and then that tlu- Pleiades help of the International Correspondence are the center. Some say they are- v. Schools, I can do. If the I. C. S. have not disprove it, as far as I know of the raised the salaries of other men, they can matter. But that is not saying it is final. raise mine. If they have helped others ave no way of peering way to advance, they can h< Ip me. To me, out into the infinite space and discerning " I. C. S. means 'I CAN SUCCEED.' the outer stellar orbs. With the innovation Make up your mind right now that not of the instrument that makes it possible, we another day shall pass until you have Build and Fly will step on a stride further as tialilco did your start toward success. with his telescope, and discover other sys- made Your Own tems and the orbs that go to make up the For27yearsmen in offices, stores, shops, factories, mines, railroads, and in the system. The more, I believe, we no into been winning pro- TrainingPlane lldy of the universe and its gloriouS- Army and Navy have through ness the more aware will we be 01 its true motion and increased salaries Train yourself in greatness and vastness. the I. C. S. More than 100,000 men and I are getting ready right now with Aeroplane of your own. Learn "Now, as we have inches and feet as lin- women it; learn ear measurements, we have the distance I. C. S. help tor the bigger jobs ahead. tii e prlnc ; ind oontrol. W( wll between the Sun and Earth as the 'Astro- No matter where you live, the I. C. S will come to IDE \i- Ai ui iU Scali 1 matter what your handicaps, or how small nomical Unit'— then, when ascertaining the you. No .1 Building ii your means, we have a plan to meet your circum- I distance of a star way out there in the stances. No matter what career you may choose, build u perl> vast infinite depths that we cannot reach some one of the 280 I. C. S. Courses will surely suit will by your needs. rise from the ground or understand figures tly like a by nor even imagina- ( rod When everythine has been made easy for you— big otic Bend now fur tii>' tion, but can only term Space, by determin- spent with the I. C. S. in the I . hour day I when one a | [i tctloi ...mt to build. ing its parallax, we are only able to express quiet of your own home will l.rintf you a bii;eer Drawings and Instructions for its distance in 'Light Years'—antl when you income, more comforts, more pleasures, all that sinele price- Curtiss Military Tractor C5 --» success means—can you let another O stop to consider that light travels al the rate Btarlot Monoplane «wOC less hour of spare time tzo to waste? Make ynur Nlcuport Monoplane EACH of 186,000 miles per second well buy a start riirht now! This is all we ask: Without cost, Taube Monoplane — Set of without obligating yourself in any way, put it up Curtiss Flying Boat Feven tablet and figure it for yourself. To our to us to prove how we can help you. Just mark Wrisht Biplane • 1.60 minds, cannot conceive of with- Cecil Peoli Racer f>oatl>kfd we anything and mail this coupon. Ideal Model Aeroplane Catalog Sc—None rree out beginning nor end (excluding the cir- TCftR ' . OUT MCRC !. . :I :ii it clng iaroplanes, Tells cle I, and to our minds things must have i pari - and mild them s INTERNATIONAL CORRESPONDENCE SCHOOLS wiili 4 pagej Bei I three dimensions to be understood by us. IDEAL AIRPLANE & SUPPLY COMPANY universe BOX 6188, SCRANTON P PA. Woosler St.. New York Cltv Now the has apparently no begin- 159-161 Expiain, without obligating mo, how I can qualify for tho ning nor end as far as we are able to dis- position, or In tho subject, brfnrr which I mark X. cern. jKI.EfTltiriL E.MilM » ii SALESMANSHIP | BHtrll Hebtlng ami H«i. ADVERTISING BUILD THIS CAR At this point we drew up at a road house, J Electric Wiring Window Trimmer BOYS or Inn. "How shot m Telegraph Engineer Show Card Writer aboul a of raspberry Telephone Painter iflv little enr dill m Work Sign JHF.t IliMl it. I M.IMIIL '_ Railroad Trainman DC built by in juice into tin neck to wash that ethereal md in v.tt m Hprhanlcal llradimnn ^ILLUSTRATING discourse down." suggested Stokes, in his ™ Marliln* Shop I'mctle* Cartooning bulldlni Toolmaker i'.. m HOOKKI.l.rF.R i price list of pari almost provoking anti-climaxical tone and h M W I" JGii Engine Operating fjSt^norraphur and Tmlifl build tins manner, as we entered the building. JC1VIL BNGINI i K Cert. Pub. Accountant lads' car. SurTf v|«jj and Happing TRAFFIC MANAGER MIM HUH >l *N sr I M.It Railway Accountant SHI IOS1R1 J- M.lM.tl. Commercial Law m Marine Engineer GOOD ENGLISH ~Slitp Draftsman _ Teacher ARCHITECT t'ommnn School Sabjrrtt SYPHERMFG.CO. Contractor and ftollder r Mathematics 156 Warren Street trrhltrcfurnl llriftimin L CIVIL SERVICE TOLEDO. OHIO. Concrete Builder _ Railway Mall Clerk Structural Engineer m U'TUHOIIII.H Ol'tttATISiJ ru mux; AMI lit , ll\fl m tnto Repairing BIG BUNCH OF FUN Sheet Metal Worker Navigation irjSpaaUh ( " TfitllM.ta At.llli I I,TI'IIP inrr*»eb l New Airship Quae with™10 AN OMISSION 1 j 1'oalu-y Ualslag IDltallao i ami*and V 3011EMIB1 \\ e wish to state that credit for the 1 Chl- 1 -se-hl-la. ) s l raphs accompanying the article en- Name - IS Other Oamee IS i titled "The City of Splendid Night," by Preaent Occupation. i'rvtty Amos Stotc. publisht in the 1919, i January, - i joke Street i \n for 10c with large Cata- issue, should have been given to the New and No logue. Dept. 72 York Edison Co. City- Lowell, Mass., U. S. A. TAMPS; Supplied with current from the lij;ht socket, a two-fan electric ventilator lias been TYPEWRITERS diff. (large bi-color), China. Jamaica, SIO AND UP. ALL MAKES. SAVE $25 TOSSOon 50 Belgium invented which, when set in a window, 1'ortugal. Venezuela, etc.. 10c: 100 dlff., nice built nl ih* factnry by the well-known" YoungProcetV" i. nt or rentr-1. Krnlal Kppttw racket. 20c: 1.000 well miied. 40c: 100 »ar. draws in fresh air and expels that already rurchajM- pric-. Writ.- for full itetails and ruini' te*. s.. 50c: 1.000 blngee. 10c: Ants, wanted, 60*. S O. Prr-iri*l. Oept 111. Chie», f in a room. TOUIC TTPtwtlTER CO. List free. I buy stamps. L. B. Dover. Overland. Mo. & Yon benefit by mentioning the "Electrical Experimenter ' when writing to advertisers. 8 70 ELECTRICAL EXPERIMENTER May, 1919 Some Government War Secrets — and the reason for the Victory Liberty Loan r E HAD promised the Allied war-chiefs Lorraine it was never fighting on German soil? They that we would have in France by July ot were brave soldiers, the German soldiers. They still "W!last year, 600,000 men. On that date we had millions of them on the Western front. And had a little over 1,900,000. We had behind them yet they surrendered while they were on foreign soil. nearly 2,000,000 in this country under training who They had a fleet which had required years and years would have been on the front before July, 1919, and and years to build and it flew the white flag without we had behind those 4,000,000 men as many more firing a shot." men as were necessary to do the job. "Four million men in France meant at least "I cannot believe that these great stores of muni- 20,000,000 tons dead weight of shipping to take care tions were wasted. In addition to the bravery of the of them, and we had that program under way and American doughboy that arrived in France and got were making our maximum output just about the into action in numbers about the 15th of July and time the armistice was signed. Twenty million turned the tide and drove the Germans back, in tons of shipping at present cost means just about addition to his bravery and his almost reckless spirit $4,000,000,000 or a little over. of determination, for which the praise cannot be too in "Did you know that those 2,000,000 men high, I say in addition to that, I believe there was France, who did so much to bring the war to an end, one other factor that brought this war to an end at had only one small battery of American-made artil- least one year before the most optimistic of us had lery behind just battery of a few them; one 4.7 and dared to hope for. One other factor, and that was naval rifles ! of the artillery the big The rest used by that Germany, her general staff, knew that back of American soldiers was made by Frenchmen in the few hundred thousand Americans that really got ot guns France. But, on the way was a great stream into big action, and back of the 2,000,000 in France, and shells that would have blown the German army was another 2,000,000 ready; and despite the fact into large off the earth. But that stuff had just come that we had practically no artillery of American it for the production in November, 1918. And is make on the Western front, that there was a great deliveries that big production that have on peak we stream of American-made artillery on the way. And to pay in December and January and will have to it is my conviction that the German staff knew that continue to pay for in February." if they prolonged the war into 1919, they were invit- ing, not certain defeat, but certain annihilation." "Our program for tanks, ot which few got into action, was, I have been told, to provide for a tank "We are asked to payfor things that were never used; in 1919 for every 75 feet of the front." we are asked to pay for shells that never were fired; for cannon that never reached the battlefront, but we are asked to pay for those things that helped in "Those are some of the things that cost money, a major way to bring this war to an end in 191 and practically none of those great supplies ot artil- instead the bringing of this to lery, of shells or tanks, even of ships, practically none of I919. And war an before could logically look of that stuff was ever used. What an awful waste! end twelve months we for it that are asked to saving the We are asked to pay for a dead horse that never means we pay for lives 100,000 or 200,000 American boys who would drew a load! It is discouraging, paying for some- of have died on foreign soil had the war continued thing that is no good! another year." "Well, let's see it it's any good. Do you realize that the German army was never reallv routed; that — Extracts from a speech J>y Hon. Leivis B. Franklin, except for a little bit of a stretch down in Alsace- Director tVar Loan Organization, U. S. Treasury 'Department. ictorv Liberty Loan —_ *_;, tr Space contributed by Ihe Clean-up Button ELECTRICAL EXPERIMENTER SCIENCE & INVENTION Prepared by American Association of Advertising Agencies cooperating with United States Treasury Department 1 ou benefit by mentioning the "Electrical Experimenter" when writing to advertisers. May. 1919 ELECTRICAL EXPERIMENTER 71 PATENT ADVICE Edited by H. GERNSBACK M one send for blank form l r with printed in In this Department we publish such matter at is of intereat to inventors and particularly to Strttctii work those who are in doubt as to certain Patent Phases. Regular inquiries addrest to "Patent Advice" up yon your rights cannot be answered by mail free of charge. Such inquiries are publisht here for the benefit of all A* ittomeys we represent readers. If the idea is thought to be of importance, we make it a rule not to divulge all details, in hundf ill over the order to protect the inventor as far as it is possible to do so. nada in the nl of inven* Schedule of fees will b- Should advice be desired by mail a nominal charge of $1.00 is made for each question. Sketches *blc. The form "1 and descriptions must be clear and explicit. Only one side of sheet should be written on. ception" sample, instructions relai obtainii t and schedule of fees sent up Ask for them. — a post ill do. NOTICE TO CORRESPONDENTS Magazine Mailer Questions on Patent Advice are answered in (321 > Carlyle Rudolph, Minneapolis. Minn., "1* there such a thing as a magazine this department every month, and naturally 5 LANEASTEB^ g g&ALLWNE mailer A machine that folds, wrap-., stamps and each question must take its turn. We have re- gets magazines all ready for mailing. I have an ceived so many letters during the past months idea which I think is worth something, but don't like to start on it until I know if there is any- 255 OURAY BLDG., that it is absolutely impossible for us to answer thing similar in u WASHINGTON. D. C. them all in the "Experimenter." Thus, for in- A. There arc certainly machines to do this. stance, the answers appearing in this issue are For instance, the Electrical Experimenter is folded and wrapt every month on a machini of letters going back as far as Oct., 1918. We this kind. While the machine does not -would therefore urge our correspondents to bear mat teal ly stamp the wrappers, this, however, can this in mind, and if an answer is wanted quickly, ly be accomplish! by a simple attachment on the market now. If our correspondent has s< correspondents should make themselves ac- thing fundamentally new, hi 1 to get in quainted with the rules printed above. touch with any of the large printing houses who have such machines and he can hear from them as to what the requirements are. Sectional Automobile Radiator Safety Elevator Device | ,^ (318) Edwin Scha'i Ralph E. Hast. Ettrina, W Va., explains X. J„ writes: (322) TO THE MAN WITH "I have DOted a photograph his invention as follows: "The idea ot tin of a pile of automobile radiators that "have^ecn ventaon is to have a device on elevator . AN IDEA damaged in the war. It has been my experience which, when the doors were closed, would close in repairing the present type ot" radiator that it a circuit, allowing the operator to ascend or I offer a comprehensive, ex- doors are closed the takes anywhere from one-halt" hour to as high as descend, but when the not perienced, efficient service for three days to fix a leak. This is true especially circuit would be open, thus rendering it impossible his prompt, legal protection and when it happens to be in the interior. My idea to operate the elevator. The device on the doors is to build a radiator in units. Should 01 would be a partly concealed socket which operates the development of his proposi- more units be damaged, they could be replaced easily but forms a constant circuit when i by others in and cannot be jarred out of place." a very short time. Kindly advise Send sketch, or model and descrip- if such an idea A. There is nothing new in our correspon- would be of any benefit, and it tion, for advice as to cost, search it dent's Safety devices of this kind have been could be patented. idea. through prior United States patents. A. It is doubtful this used for many years, and are in use right now. that a device ot kind etc. Preliminary advice gladly fur- instance the York Subway Bie- would prove satisfactory, for the reason that there Take for New nished without charge. would probably a rs, particularly the ones at 181st Street and be good deal of trouble to My experience and familiarity with Broadway, operate with tins device. interconnect the various sections, and there would various arts frequently enable me to probably be just as much trouble in keeping these accurately advise clients as to prob- connections from leaking well-made as in a radi- Depth Bomb able patentability before they go to ator. That a device of this kind can be patented any ex; is also very doubtful to us. (S23) George W. Curtis, Detroit, Mich, has in- Booklet of valuable information vented a depth bomb which works on the sea and form for properly disclosing water conductivity plan by means of which con- your idea, free on request. Write tacts are closed when the sea water enters the today. Telephone Appliance intake of the bomb. Our advice is asked as to the practicability of this device. RICHARD B. OWEN, Patent Lawyer 164 Owen Building, Washington, (319) R. C. Kcnnan, Indianapolis. Ind., sub- A. There is nothing new about this device- D. C. 2276-8 Wool worth Bldg , New City mits a drawing and description of a telephone many bombs of this kind having been proposed York appliance which is designed primarily to eliminate during the war. The regular depth bombs, how- trouble for the man who talks several feet away ever, working on the hydro-static principle, are from the phone and expects people to hear him very much simpler and better. on the other end of the line. The arrangement also permits using the phone without holding the receiver in the hand. Our correspondent wi advice if thi ; patentable and if we think a market exists for such a device. TRADEMARKS A. This is one of those devices of which probablv five thousand have been patented in vari- ous forms in the past. Our correspondent's de- \ice has a lever at the end of which the receiver COPYRIGHTS is fastened. The arm and the receiver swing in a half circle, and is then locked. The subscriber can then talk without using his bands. The hook Before disclosing an invention, the inventor should write tor our blank connection is automatically established as soon as form "EVIDENCE ON CONCEPTION." This should be signed and witnessed the lever is raised. A There is nothing new to this and. as we and if returned to us together with model or sketch and description of the inven- beer stated, many thousand similar ones have tion we will give our opinion as to its patentable nature. ented in the past. There does not seem, moreover, Our illustrated Guide Book. TO OBTAIN" A PATENT, sent Free on to be a market for such an appliance. HOW request. Contains full instructions regarding Patents, Trade-Marks, Foreign Patents, Our Methods. Terms and 100 Mechanical Movements illustrated and de- scribed. Articles on Patent Practice and Procedure, and Law Points for inventors. Trolley An actual search .>f United States patents made in all cases before preparing application for patent Electrical Cases a Specialty Highest References Prompt Attention Reasonable Terms (320) Frederick E. Barber. Syracuse, N V . encloses a sketch and description of a device to keep the pole of a trolley from jumping off the FREE COUPON! wire. Our advice is as VICTOR J. EVANS & CO., Patent Attorneys views as to trolleys a A We have exprest our New York Offices: Pittsburgh Offices: Philadelphia Offices: Our advice great many times in these columns. 1001 to 1007 Woolworth Bldg. 514 Empire Bldg. 135 S. Broad St. Our ideas were to trolley "inventors is: "don't". Main Offices: 779 Ninth Street, N. W., Washington. D. C. fully exprest in a recent answer to one correspondents in these columns. We refer to \ame Address our March issue, page 825. Patent Advice Ho. 3 18 You btneAi by mentioning the "El perimenttr" when 72 ELECTRICAL EXPERIMENTER May, 1919 Phonograph Needle (324) R. W. Xapper, B. Guiana, S. America, Patents Promptly Procured asks us: "Do you think that a patent of any value could be secured on a double-ended grama- Send sketch or model for actual search phone needle, i. e., a needle sharpened at both of U. S. Patents. Highest references. ends? This would tend to save steel, as each Personal service. Moderate fees. Write U.S.PATENTS needle could be used twice instead of only once." A. We do not think that a needle of this kind for Free Patent Book. and believe needle Our facilities for securing would be of great benefit we a GEORGE P. KIMMEL, Patent Lawyer of this kind was once tried. The reason is that patents enable us to give 99-T Loan & Trust Bldg. Washington, D. C. a needle of this sort cannot be held as securely prompt and reliable service at as one with the squared off end; it tends to rattle reasonable rates. Inventors because the upper end is not supported except by are invited to write to us re- a sharp point. garding questions appertain- Searchlight PATENTS ing to securing patent protec- Inventors Invited to Write for Information, (325) Joel Silver, Newark, N. J., submits the tion. All matters receive following idea: "T think that if about five search- and Particulars prompt attention. Send sketch lights have their rays focused on the inside of Highest References. Best Results. Promptness for preliminary examination. another larger searchlight (see illustration) there Assured. will be more power; hence a small searchlight, WATSON E. COLEMAN Books free on request with the aid of others, can be made more powerful. The rear of the main light (A) is cut open (B). Patent Lawyer All the searchlights (C) have their rays focused 624 F Street N. W. Washington. D. C. A. M. BUCK & CO. upon the center (D) of A. With very good re- flectors and a very powerful lens, I am quite sure Patent Attorneys that a longer distance will be obtained. That is, it will be five times as powerful as one of its How to Get Rid of Moles 205 Second National Bank BlcJq.. size." A simple, safe home treatment — 15 V/ashinatcn. D. C. years' success in my practice. More powerfulrug Moles (also BIG growths) Dry Up. 4// sides ofsearch Ask for Free Booklet of Full Particulars light clothed rv/'fh WM. DAVIS, M.D. reflectors Inside 4 1 40 State Street Perth Amboy, N.J. -•-Jill' roys focuseo PATENTS Opening here 5 Learn WATCH REPAIRING LACEY & LACEY l'ou caa learn by our modern and orig- inal Byitem of instruction every part of the Watoh Repairing Trade at home Attorneys-at-Law—Patent Practice Exclusively as good or better than at a shop. You can earn money while learning end secure a Solicitors of well paying position or start in business after completing our course of instruction. Good watch repairers are always in demand and earn, U. S. and Foreign Patents from $20 to $36 per week. For particulars apply to the Milwaukee, Trade-Marks, Copyrights Milwaukee School of Watchmaking 165 Mason Si , Wis 639 F Street, N. W., Washington, D. C. Write Us for Our Free Inventors 1 Book MUS3C TAUGHT FREE PATENT-SENSE Searchlights 1869. .ESTABLISHED boo can Moid TTUamx. UKtihu quuMj| A. While the idea is ingenious and no doubt In Your Home. Write today for our booklet. It tells novel, it certainly is not practical, for nothing how to learn to play Piano, Organ, Violin, Mandolin, could be gained either electrically or economically Guitar, Banjo, etc. Beginners or advanced pupils. to arrange the searchlights as shown. The reason American School of Music, 57 Lakeside Bldg., Chicago is that one search light can be made to give the same amount of light by using large enough car- PATENTS corresponding of bons and consuming a amount current. Of course, multiplicity searchlights a of Lighting Fixtures" INVENTORS: Send us sketches or a are used in a great many cases, but not to con- "Hang Your Own centrate the light on a point. They are usually One Light Bracket $1.05 4 Light Shower $6.15 model of your invention and a de- employed to throw the light over an extended — Semi-Bowls $5.83 Plate Ball 85c, complete scription of the device for advice surface. — & with glassware. Wired, Fine finishes. Send for in regard to the best way of ob- Chemical Flask Photos complete line. taining patent protection. Our practical (326) Eug. Lavigne, Montreal, Can., submits ERIE FIXTURE SUPPLY CO. experience covers a period of twenty years. Our diagram and sketch of a combined water bath and Sta. Erie, Pa. patents is sent free on request. All C, hand-book on boiling flask. It is shown in our illustration. He communications strictly confidential. Write us today. wishes to know if this idea is patentable and it TALBERT & TALBERT it is practicable. Patent Lawyers SELENIUM CELLS Guaranteed 99' f selenium 4287 Talbert Bldg. Washington, D. C. pure Made by people who know their business, for the most difficult work, requiring very sensitive, quick acting cells. Special cells to order. Competent Patent Service LABORATORIES, Inner boiling ftosk THE SELENIUM By a Former Examining Official New York Offices, 56 West 45th St. of the U. S. Patent Office Norman T. Whitaker EASIEST SHORTHAND Learn in 5 evenings homestudy; then acquire speed with K.I. Lawyer and Engineer Shorthand. Amazingly simple, ^Cortr — Hs. Write :.. ra- 480 Whitaker Bldg. Washington, D. C. ..j brief orlte me- notes Branch Office. 87 Nassau St.. New York City. p jDaite ' at lecturesi, meetings : keep con- . fidential diary. Big help In any, INQUIRIES INVITED aid In Liquid profession or business to Boiling roar career. Osed In Anny, Navy, courts, com- 6e heafed mercial Bchoolg; by Public and private steno- water graphers teachers, bflcfit coat. K. I. Shorthand people. Including YOU. Proof Lessons. -for h usy 1 JJ Guarantee and irocburewithTestimomals'ree, postpaid . Address: KING INSTITUTE, EL 300, Station F. NEW YORK CITlf J^£ Feldman's "Geyser" A. While no doubt a patent could be obtained Hand Books on Pateats. Trade Marks, etc.. sent efficient on this device, we do not think it would be of free Our 70 vears of experience, service, Electric Water Heater and fair dealinc assure fullest value and protection much value for the reason that it could be used to the inventor. Patents procured through us re- only in very few cases. As our illustration shows, American. Instantaneous Hot Water ceive free notice in Scientific the evaporating water would flow into the central MUNN & CO., 618 Woolworth Bldg.. K. T. flask and it is quite certain that more or less water would find its way into the central flask, FELDMAN MFG. CO. Washington Office, 625 F St., Washington, D. C. where surely it is not wanted or needed. This is 1500 Times Bldg. New York City our main objection to the idea. RAISE BELGIAN HARES C°T In the June issue: "HOW TO FINANCE TAM MERER HUGE PROFITS easily and pleasantly made We AND MANUFACTURE A PATENT," by furnish stock sod pay you 86. 00 a pair and St-nd 10 cents for my remarkable Jay G. Hobson. express charges for all you raise. Contract hook, "How To Stop Stammering." and book* 'Fortunes id Hares", by mailFraw, of stammering. A very important article for all inter- s Kill the fear •UT10HAL FOOD S FUR ASSOCIATION Re education the key. ested in patents. r DOT*. 2* MILWAUKEE. W1SC. Chicago, III. The Hatfield Institute. 109 N, Dearborn St . © You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. May. 1919 ELECTRICAL EXPERIMENTER 73 COLD LIGHT 1 1 ontinutd ]• om pagi -i i proper condition! tl»- imall li^lit wave may be given <>IT 1 >• t lie electron without affectiiiK the whole molecule in the least. That is cold tight. An interesting experiment can I Formed with i vacuum tube, which i trate-. completely the principle ol light auction by ionization, and at the tame plains tin- principle >>f the Moore Unlit. Few people, othei than scientists, realize what a peculiar tiling the production of light in a vacuum iir Geissler tube is. The light is evidently not the product "I I but depends on the fact that the electric -.park breaks the «a> molecules up into charged particles Or ions. And tins phe- nomena is most noticeable when a certain degree of exhaustion is reached in the tube. When air is pumped out of a tube in which there is an electric spark discharge, several different stages, as shewn in I i Become an Electrician In One Year Here are successively reached. \t first the dis- charge in the tube is the ordinary disruptive Or Learn An Electrical Trade In 6 Months spark. In the next Stage it forms a quiet thread of light thru the tube. Then the school teaches electricity thoroughly, from the very fundamentals, including the thread of light becomes a broad pencil of THIS laws and principles of electricity and the theory of direct current—together with light, and finally with more exhaustion the practical lectures and problems, actual training in laboratory work and electrical whole tuhe is filled with a Sbft luminous machine departments of designing, building, repairing, installing, operating, etc. And the glow, which is technically known as the faculty here are practical electrical engineers who know how and what to teach because positive column. This is the point of high- they know what knowledge and ability the great field of Electricity requires. est conductivit) of the tuhe, and may be As one szanple of this school's thoroughness and air reached with try pump. With prai thai training and development witness tin- pictures R. O. T. C. UNIT further exhaustion, by means of a special above showing rtew of tfotor G Department, The War Department of the U. S. Govern- where Btudei making air pump, the resistance increases, the cold ment has recently authorized Junior and til connections and performing all tin- necessars opera- Senior Reserve Officers' Training light disappears, and the point is reached Corps Units tions, on Ui" nil" practical basis as in a powei In this school. Student! in courses listed where X-ray phenomena and fluorescence or large industrial concern. below are entitled to join Junior Unit If they wish to »o so. R. 0. T. C. membership appear. The color of the light in the tuhe The thorouRhness in essentials here, the practical offers such advantages as ; Complete tree able faculty, together with this school's depends on the gas used in the tuhe and training and uniform equipment, free summer training broad facilities and tntenslre iblllUes, are the reasons camp trip, summer uniform outfit and free is undoubtedly the product of the ions. why you can become an Electrician here In one year, special technical Instruction. Membership and all obligations cancelled on termination Electrical Trades In months. Just before the war a Frenchman, Claude, or master one of the 6 of school work. devised a means of producing in quantities If you are determined to achieve success in the the rare gas, neon, which gives an intense Electrical Field this Is your school. You will acquire and accomplish more In a shorter time at a less cost "i carbon yellow lulu a vacuum tube. The and be a fully developed, practical electrical man when dioxid which Moore uses gives a white you finish. Mall the coupon at the right and get com- MAIL THIS COUPON NOW light. Other gases, possibly rare ones, may plete Illustrated and descriptive details of the advan- tages this school affords. If interested in Electrical still, and School of Engineering of Milwaukee, be found which are better helium Engineering with U.S. degree, check same on coupon. (88) 373 Brozdway, Milwaukee, Wis. has been suggested as a standard by some. Mail the coupon now. However, up until the time the U. S. Without nblinatliik uniish detalli low. Government discovered the way of pro- You Can Earn While You Learn Electrician ducing it in immense quantities for balloon Electro-Technician will provide you with part time employment too to Electrical Engineer (3 yrs.) work, during the war, it was rare WEto help defray your expenses here and give be practical. The more the conditions in you actual outside experience — without interfering SPECIAL 6 MONTHS' COURSES is explained In such a light can be improved, and the more with your class hours—which fully OUT catalog. Mail the coupon. nearly the light is a pure ionization or cold Draftsman light, the higher the luminous efficiency Electrical Trouble 4. Lineman Electrical Wlreman will he. An interesting table is given, show- Sch(tool of engineering Electrical Motor Repairman ing the progress which has been made up to Telephone Trouble & Repairman tube. the present, including the vacuum of Milwaukee Electrical Meterman Various Luminous Efficiency of An Electrical Technicians' Institute Illuminonls NAMK Candle 2 per cent Department of Practical Electricity Gas mantle 5 per cent (88) 373 Broadway, Milwaukee, Wis. STATE Carbon lamp 6 per cent Cm l'i Flaming arc 15 percent i CATION AGE. Vacuum tube 40 per cent REVOLUTION COUNTER FOR DYNAMOMETER HAVE A BEAUTIFUL FACE (Continued from page 39) YOU duration of thirty seconds. The time ele- BUT YOUR NOSE ? ment may be changed at will by the use of saws of any desired number of teeth. To start the apparatus, the starter button is brought into action until both brushes bear on the metal drum. This completes the circuit and engages the clutch thru the electro-magnet and spring thus startitig the counter. At every swing of the pendulum, the circuit thru the solenoid is made and broken, thus drawing the saw—as illus- trated—thru a circumferential distance equal to one tooth. After thirty swings of BEFORE AFTER the pendulum one brush is again hearing on TI1IS DAY and AGE attention to your ftD] Permit no one to see you looking otherwise: it will i you constant- is an absolute nee tlu moat the insulated section of the drum and the r< ly make rpvl* the fallu Ufa No! wuj tumid you r ittrao- Is to be youi ulUmati counter clutch is disengaged. A reading of I Model -r the counter gives accurately the number of b youi affori i, but rou vti U Qnd I In without " nt 1 in general fudging P Wholly, by your ill one's daily occu- revolutions ,,f the dynamometer in thirty "lookt." therefore it pays to :: at Bight, seconds. This counter may also he used in Write today for fret booklet, tchich tetU you how fa correct •il-iheptd nosu uithoul cost ij not lalisfactory connection with a fuel weighing apparatus. M. TRILETY, Face Specialist 1162 Ackerman Bldg., Binghamton, N.Y. Contributed bj W. H, WEBER. You benefit by mentioning the "Electrical H.vfoimenter ' when writing to advert 74 ELECTRICAL EXPERIMENTER May, 1919 circuit is to amplify the audio frequency currents of the first vacuum tube. This RADIO DEPARTMENT audio amplification is accomplisht thru • Continued coils L and L ; , which are mutually coupled MURDOCK New Regenerative Vacuum Tube Circuits with this arrangement, and it is possible to amplify the signals to 1000 or more times (Continued from page 33) their original value. It was possible, in tests, to amplify signals received from a No. 55 these wave lengths, the proper size induc- distance of 5000 miles to such a value as tances are always to be utilized. It is ad- to cause the incoming signals to be heard visable to use this circuit whenever large twenty feet away from the telephone re- amplifications are desired at extremely low ceiver. The telephone receiver was equipt wave lengths. Tests have been made with with the proper megaphone. this circuit in comparison with other low In Fig. 7 is delineated a radio telephone wave length regenerative circuits, and it circuit using a vacuum tube for the genera- was found that the above circuit gave bet- tion of sustained oscillations. The grid and ter and more efficient results and that it plate are coupled magnetically thru in- was possible to produce regeneration in ductance L = , which also energizes the an- the plate circuit with much greater ease tenna circuit thru inductance Li. Con- than that obtainable with the usual type of denser C is used to tune the oscillatory' circuit. circuit CLc. The plate voltage in this work A similar but a more complicated circuit is considerably higher than the plate voltage is shown in Fig. 5. The radio frequency used in receiving sets and it usually ranges bridging condensers C3 and G, are used to from 300 to 1500 volts. This is usually permit radio frequency currents to pass accomplisht by the use of the generator freely to the plate. G. The inductance L 3 which is a choke Pre -War Prices Complete Complete 2000 Ohm 3000 Ohm Double Set Double Set $400 $500 Without exception the best radio receiver value in the world. Positive satisfaction guaranteed. Fourteen Days' Special Form of Loose Coupler Provided with Five Coils, for Use with Regenerative and Trial, and money back if Wireless Telephone Audion Circuits Here Described. they don't make good. Get Your Set Now. With all the above circuits so far de- coil is used to prevent high frequency cur- scribed, it will be noticed that the regenera- rents from the plate circuit entering the We are prepared to supply tive coupling is accomplished in the an- generator. Modulation is accomplisht by promptly your requirements for tenna circuit, thereby amplifying the in- shunting a telephone transmitter T, thru coming radio frequency oscillations and a resistance R and battery B across the good radio instruments. therefore producing maximum amplification grid and filament of the tube, as indicated. Ask for Bulletin No. 19. without the loss of any feeble currents due Another successful circuit is shown in to coupling in the secondary oscillatory cir- Fig. 8 and voice modulation in this circuit cuits, which means of regeneration of in- is accomplisht by coupling the telephone coming signals is accomplisht with pres- transmitter thru an induction coil I, com- WM. J. MURDOCK CO. ent forms of circuits. Thus, it is seen that prising coils L 3 and L.. The primary L. direct results and better efficiency can be is connected to the transmitter and battery 55 Carter St accomplisht with the circuits described. B, as shown. The modulated wave is im- Fig. 6 outlines a circuit similar to Fig. 5 prest upon the grid in the vacuum tube, Chelsea, Mass. in which the plate of the first vacuum tube which wave is superimposed upon the main is coupled magnetically thru coils 4 and radio frequency oscillations. Pacific Coast Representatives L Ls. The purpose of another vacuum tube (Continued on page 76) The Keeler White Co. 221 Second St., San Francisco, Calif. MAKE ELECTRICTY BY HAND Simply turn the crank and make 110 volts A.C. While they last Only $5.00 Order from this ad. House-Lighting Plants $225 to $2,100. Battery Charg- ers. Dynamos, Motors, all sizes. State agents with $500 capital wanted. WATSON ELECTRIC CO., Dept. 14, Gas Building. Chicago WIRELESS IS SIMPLE when the Summers' theories of wireless are applied to wireless systems, transmitting and receiving apparatus. Will advance the wireless art by leaps and bounds. Get on the right track with your experiments. This booklet should be in every home and school. United States and foreign copyrights. Price $2.00 reg- istered postpaid to any part of the world. Amplifier, the Circuit of the Second Audion Being Magnetically Coupled Memphis. Mo. Two Stage Audion Address FRANK E. SUMMERS. to the First Audion Circuit. Amplifying Power 1,000 Times and Better. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. May. 1919 ELECTRICAL EXPERIMENTER 75 Wireless in Ten Weeks We teach you in your own home during your spare time Thousands of operators needed for America's Merchant Marine The age of wireless is here. I h<- experin has passed. Wireless now equals in impor- tance telegraphy, and telephony. It ha^ assumed its place among the great commercial Industrie the- earth. So rapid lias been the development and growth oi wireless in recent years that there has been left in its wake a tremendous shortage of oper- ators. Actually thousands upon thousands are now- needed for permanent "peace time" positions offer- ing wonderful opportunities for advancement. Earn up to $200 per month In the short period of ten weeks we can make of you a wireless operator, a man with a profession, independent, and not subject to the rise and fall of wages in the labor tries arc as high - r month. There is in the merchant marine, the army, the nnv a laml station, awaiting everyone complete nrse. One of the Riant wireless towers which keeps us in We give you this training at home, by mail, in your spare constant communication with Europe time. It is not neo or you to lose any time from your work to take the course. Free Instruments While a student of our course, we present absolutely FREK to every student enrolling with us a Standard Set of Instruments (the same as used by the Government in testing applicants for first grade commercial licenses). This machine sends and records messages. Travel the world over or locate at a land station in America. America is spending billions of dollars on the mightiest navy and merchant marine in the world. Practically all vessels are being equipped with wireless apparatus of the most up to date type. Thousands of operators are needed now. The field affords a wonderful opportunity for the man who starts now to master wireless. Our students actually pass the com- mercial examination in ten weeks or less* Get your instruction The National Radio Institute, headed by au- A Valuable Book Free thorities who have been closely allied \\ir the Nation's ernmcntal training of students, has perfected Our booklet. "Wireless—The Opportunity of Today from I-uture." <- an casii> mastered course in wireless telegraphy and the Greatest Field of the g« complete information in regard to our course, the quick Capitol. Our course where) ;ire taught completely in ten and e;t- by which yon can master wireless is endorsed by officials weeks, either here in V. a our large and other important facts you should know. It is by mail. Many of free. Just mail the coupon. No obligation whatei of the U. S. Govern- our students are ready to take up actual wire- your part. :i much less time. The course is ment. - founded on actual practice, hence the rapid : FREE COUPON progress of the student. NATIONAL RADIO INSTITITE. Dept. W, Washington. D. C. Send me. free of charce. ; "Wireless The Opportunity of Today and the Greatest Field - particulars NATIONAL RADIO INSTITUTE I the Future." with full restardinc your us in week-' Home Study Course, and your Dept. W Name 14th and U Streets, N. W. Washington, D. C. Address . • .... the Electrical Experimenter when writing to adieu 76 ELECTRICAL EXPERIMENTER May, 1919 NEW REGENERATIVE VACUUM TUBE CIRCUITS. (Continued from page 74) Another circuit to accomplish the same result as above, is indicated in Fig. 9, in which case the oscillations are started thru the coupling coil M and the voice modula- tion imprest upon the grid circuit is ac- TWO TYPES OF MICA TRANSMITTING CONDENSERS SUITABLE FOR MODERN AMATEUR APPARATUS. 2 1000 VOLTS. .004 MFD. Make Your Wireless Apparatus Send Further Last Longer and Work Better The wireless amateur and experimenter is once more busy constructing apparatus for use the moment that orders go forward allowing amateur stations to open. First Form of Radiotelephone Transmitting Circuit, Utilizing an Audion, of Interest to The kind of apparatus you used before the war doubtless answered your Amateurs. purpose nicely, but just consider the tremendous advancement made in the art during the past two years and you will appreciate your modern apparatus complished thru the telephone induction the must contain several new types of equipment to bring it up to date. coil whose secondary is connected thru grid and one leg of the coupling coil M„ and the other to the main oscillatory coil DUBILIER inductance Li. The primary of the induc- MICA CONDENSERS tion coil is connected with the microphone proved their real worth in the Navy, the Signal Corps, and as a part of the equipment of and battery as indicated. Tuning is ac- the righting Airplanes both here and abroad since 19 16. complished with condenser G, which is in You can now purchase a genuine DUBILIER MICA CONDENSER for your new set for any the oscillatory circuit GLi. Energy trans- voltage and capacity. They replace Leyden Jars with greater efficiency and without brush discharge and with negligible losses. They are compact and indestructible. Made in any capacity and up to 1,000,000 volts. Special condensers supplied for ex- perimental work. Used in practically every Government installation. DUBILIER MICA CONDENSERS are now ready for your use. Type A Navy Type .002—21000 volts $11.00 $18.00 004—21000 volts 20.00 35.00 DUBILIER CONDENSER CO., Inc., 217 Centre St., New York For Great Britain, Address DUBILIER CONDENSER COMPANY, Ltd., 1 & 3 Stephen St., London, W. I., England Boys! You Can Make Your Own Electrical Ap- paratus with the aid of these wonderful books Home-made Electrical Apparatus By A. M. Powell Second form of Audion Radiotelephone Three wonderful big books, chuck full of just the sort of information Transmitter with Magnetically Coupled Mod- SCIENCES -!*°8 you have been looking for and at a price within reach of your pocket book. ulating Circuit. JtRTSJim jj Each volume is printed on heavy paper, contains 75 pages and over 60 illustrations, complete working drawings for making every sort of electrical ferred to the antenna circuit is accomplished %m EMAM them. The price is only 25 apparatus. Written so you can understand thru the plate inductance L^, inductively IELECTR1CAL cents per copy practically the cost of publication. See partial table of — coupled to the antenna inductance La. To APPARATUS contents below and order now. The supply is limited. Static Vol. I Contains working drawings and directions for making all sorts of Ma- the impedance of the grid circuit \ in -tnree Paris reduce chines. Static Apparatus, Home-made Batteries, Storage Cells, Transformers. Recti- [Y ', VOL.11 due to the high inductance of the secondary IwSK fiers, etc- directions for all sorts of Voltmeters. Am- l^ «,««, Vol. II contains tcorking dratcina* and of the telephone induction coil, it is neces- meters, Galvanometers. Switches. Rheostats. Telegraph Keys, Sounders, Telephones. Shocking Coils. Spark Coils. Experiments, etc.. etc. sary to shunt a capacity G of considerable ^rfVMM and directions for making all sorts of Dynamos, |fe#| Vol. Ill contains working drawings magnitude to overcome this excess im- 1— ','&" Motors. Electric Engines. Miniature Lighting Plants. Wireless Telegraph Apparatus. -wfr- -i' Tesla Coils. Wireless Telephone. Electroplating, Experiments, etc.. etc. pedance. Any of these wonderful books will be sent to you postpaid for 25 cents. COLE & MORGAN, Inc., Publishers and Booksellers COLE 5> MORGAN inc. P. O. Box 473, C. H. Sta., New York City tEfje breakers! Atlantic City's Newest Fire-Proof Hotel Ocean Front. Unusually attractive during the Autumn and Winter sea- sons. American and European Plans Luxurious lobbies, spacious verandas and sun parlors overlooking the ocean. Charming afternoon musicales and evening concerts. A palatial residence for those seeking rest and recreation. Sea water baths. Fireproof garage. Illustrated booklet sent on request. Third Form of Audion Transmitter for Radiotelephony. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. ! May. 1919 ELECTRICAL EXPERIMENTER 77 PUTTING IT OVER ON FRITZ. (Continued from poo* '>r ilnis marked i »l Five Points of latum the position <>i even wireless -.fin l»-r could be ascertained abandoned. This i .11 even time, and tli<. the was guarded jealously during the BRANDES war, it noVi can be L harmless, and every other nation knows just how the prophet \ was made Superiority It was not often that the Germans kepi Allied brains working overtime on In a single instance, however, the I Inns Brand es wireless head thought up a devilishly clever plan loo' ting Becrel information into German score i on the five fat tors w.^ called for weeks and weeks the that determine the efficiency "Nauen-Madrid Buzz." Brando "Superior" and value of receivers for Nauen, of course, was the official German Head Set, com- plete with head band, $6. A profession- butli and nment wireless station, while in al set within the means of every ama- professional amateur Madrid, was teur. Spain, situated i itation ca 2000 ohms. use. pable of sending messages to any pan of the German empire in Europe. During all Sensitiveness: Brandes receivers do more than make weak signals audible; they the months of the war in which direct make them readable,—clear and sharp This is because both receivers are exactly ccimnHiiiicaii.ui between German] and the matched in tour. outside was severed world practically offi- Dependability: Made by hand by an organization which manufactures wireless cial war and "inspired" bulletins news came receivers only, carefully measured by a micrometer for exact construction, and out from Madrid. Nauen thru The latter tested against a Standard receiver— Brandes headsets can be counted upon for station sent hack neutral news ami views of absolute dependability under every condition. the war. Lightness: Because Brandes headsets were first designed for professionals, they In the spring of 1917, however, a came are so made that they can be worn long hours without discomfort. queer development Every now and then Service: With ordinary care, Brandes receivers give service indefinitely. would seem t<> he badly bothered by Hun- "static" or by some imperfection in the dreds of owners would not exchange sets several years old for new ones. sending apparatus. The station would emit Appearance: Compact in size, correct in head band design, with an orderly ar- an unintelligible buzz, like unto no message rangement of cords, and made from the finest materials, Brandes headsets have known to operators. This was regarded a handsome, efficient appearance. with grave suspicion by the Allied intelli- gence departments, and when Madrid Booklet "E" will be sent upon receipt of 4c in stamps. started the same thing a whole corps of military wireless detectives were assigned C. BRANDES, Inc. to the problem. No one doubted that this ^V^^i iine new form of communication, but what on earth could anyone make out of that continuous buzz? Complete line of Brandes receivers for those in Western States and Pacific Weeks past with no light on the ques- Coast. Catalogue "E" on request tion. The two Stations had grown bidder Balboa Building FORD KING San Francisco, Cal. and were using the buzz constantly. Valu- able inform ed to the it was made practically certain that the "buzz" was responsible. The mystery was solved by the help of a Commercial lucky accident. The technique of studying every code wireless message of the enemy had been to take down the sounds of the Telegraph Apparatus * T- OcrOREST spark on cylinder record; -fe.5Hl_ a phonograph | ~~X*^t— WIRELESS-wSji^ this gave the intelligence officer an accurate i -»^V SYSTEM ^S-^ reproduction at any time he desired. On I Bargains ~~f* K/*yt/ > W-iP.1 the occasion mentioned an officer had been J trying to establish some similarity between several the records without suc- of Standard twenty ohm (POOO cess, when his machine ran down. As the Telegraph Sounders at «P*-each needle grated to a stop on the cylinder the officer sat up suddenly. He thought he Standard Telegraph 125 detected something that sounded jusi a Keys at leach De Forest's New Catalog little like a message He wound the phonograph and turned 110 Volt A.C. illustrating and describing the very ed indicator down so that the record Dynamos revolved only a few times a minute. Then latest and best in he applied the needle again. Aha! There Three Bar leach imething there! Tho this arrangement gave him insuffi- Four Bar 2^ch RADIO APPARATUS cient to enable him to sol lie had For Discriminating Users the idea. Next the phonograph cylinder Five Bar 2^ch was attached to a motor, revolving at three is ready for mailing. Complete in- hundred revolutions a minute, and several For other bargains see pages 90 <* 91 formation regarding the Forest records taken at high Speed of the peculiar De buzz. When these records were re-run at "Unit" Set, Honey Comb" Coils moderate speed it was simple; the messages Skinderviken Telephone Equipment Co. (a radical departure from decoded in an hour and were found previous were Abbreviated Address to be questions and answers on topics the forms of apparatus), variable air Germans were not even supposed to know- STECO-2118-2136 N.Clark St CHICAGO and fixed condensers, wavemeters, existed ! The method used by the Germans and by variometers, detectors, etc.. will be the Madrid operator had been simply to sent upon receipt of to punch in the message on a perforated paper 10c defray roll. Then running this thru the sending TELEGRAPHY postage. Both wire equipment at high speed the message had and wireless, and Station Agency taught thoroughly and quickly. BIG WAGES NOW PAID, rapid a gone into the ether waves at too some of our recent graduates procuring $138.00 per rate to be caught by ordinary methods. At month toatart. Great opportunities for advancement. Our De Forest Radio Tel. & Tel. Co. Hohool tho oldest and laruest—annual enrollment €00 students. the other end the receiving station used the bvndorsed by railway, tele* raph, wireless and government offi- 1391 Sedgwick Ave. New York City phonograph equipment to catch and record cials. Expenses low—chance to earn part. Catalan free. Write. the message. DODGE" INSTITUTE, 22nd St. Valparaiso, lad. You benetit by mentioning Ike "Electrical Experimenter" when writing to advertisers. , —: ; ELECTRICAL EXPERIMENTER May, 1919 lOTRU WITH THE OMNIGRAPH NUMBER 2 The Omnigraph Went to War — IF you have ever stopped to figure out But It's Home Again the terrific cost involved in publishing Uni- the During the war, scarcity of material and orders from the Government and from the leading a magazine, and small amount of the Govt, in teaching versities, Colleges. Telegraph and Technical Schools, closely connected with money that you pay for your issue each to the trade. Codes, made it impossible for us to make prompt shipments to individuals and the month, you probably wonder how a pub- We are now filling all orders promptly. lisher can afford to give you as much as The Omnigraph Automatic Transmitter will teach you the Continental and the Morse Codes, at it for the home, in half the usual time and at the least possible expense. he does. If were not advertising Buzzer, or with Buzzer and Head Phones or with bounder, THE OMNIGRAPH. connected with vour carried, he could not do it. Your 20c mil send you unlimited Wireless or Morse Code messages, by the hour would not buy a magazine one-half the aild at any speed you desire. Im- size, or quality, of the "Experimenter" un- possible to anticipate. less that the We offer the Omnigraph as a positive magazine were supported by success and with the strongest of en- advertisers who use its columns every dorsements. It has been adopted by month. the TJ. S. Government, Department of Commerce, and is used to test all operators applying for Radio licenses. The Electrical Experimenter, especially, Telegraph Schools use Many leading costs a vast sum of money every month to The Omnigraph to send to their stu- dents in preference to hand sending. produce. The magnificent wash drawings Ask us for their names if you so de- and expensive cuts that you see in every is- sire. We have hundreds of unsolicited sue and which have made the "Experi- testimonials and with permission we are publishing one of them. menter" famous are only one of the many Jersey Ave.. items that makes the publishing of your 2 5 New Jersey Ave. 205 New Anglesea. New Jersey. Anglesea. New Jer-.-\ magazine a severe and heavy strain. The Feb. 20th, 1810. Feb. 17th, 1919. price you pay for your copy helps to meet The Omnigraph Mfg. Co.. The Omnigraph Mfg. Co., Cortlandt St.. New York I :;;* Cortlandt St.. New York Cits 39 part of this expense, but the advertisers your letter of 19th inst., I am Dear Sirs: — K./c.-iv.-d my Omnigraph No. 2 with a set Dear Sirs: — In reply to Dials and tiLAD to give you permission to use my previous letter foot the most of the bills. Don't let that of Morse and an extra set of Con t i nental wish to thank you fur your prompt shipment. in any way you see fit. not receive enough Morse to fool you, however. They are not doing it Five minutes after I had received the box, 1 had it Two weeks ago I could person was saying but today I can unpacked and working. 1 cannot praise it too much understand what a for any love of the "Experimenter"— it is receive about ten words per minute on my Typewriter and a friend uf mine as soon as he heard it. said a business proposition with them. "Why, man, that send; PEBFECT Morse and Wire- when the OMNIGRAPH is sending. Each First Grade Commercial Radio Operator's less." I will give you all the praise thai I can I I have a better my and every one have something that they myself doubted that the machine would do all you License and am using the OMNIGRAPH to telegraphy. stated but it does all you state AND THEN SOME receiving and to fit me fo- land feel is of interest to you. Perhaps it is a wishing you the best Wishing you the best of success for the future, I Hoping to be of help to you and piece of merchandise that they want to sell; of success in your business. I remain remain, Very truly yours, Very truly yours, a new wireless outfit, a correspondence (Signed) Thomas W. Braidwood. Radio 3 C Z. l Signed) Thomas W. Braidwood. Pres. Cape May County Rad-o As: Pres. Cape May County Radio Aaso course that they know will improve your If you are a beginner, it will make you an operator in the shortest possible time. mind and equip you to earn more money a better one. if you are already an operator, the OMNIGRAPH will make you maybe it is a book or a novelty that you or order direct through your Electrical Send for free catalog describing 3 different models 59.00 to J23.00 — but, it is, satisfied or money bacK. would enjoy having; whatever Dealer. We sell the Omnigraph under the strongest of guarantees—you must be your they are willing to pay their good money to St., New York THE OMNIGRAPH MFG. CO., 39 L. Cortlandt support the magazine in order that the How did you learn to talk? By listening. JUST LISTEN,—THE OMNIGRAPH WILL DO THE TEACHING magazine can print their advertisements. The more advertisers we have, the more income there is each month, and the pub- lishers of the Electrical Experimenter have committed themselves to putting back into the magazine, in enlarging its size, and BIG 300 PP. improving its articles, and its drawings, every penny that comes in through the cir- DUCK'S Wireless & Electrical culation or advertising. You will notice that with this issue eight more pages of largest and most Catalog is now as it always has been, the pure text have been added, making this Mailed complete and dependable Wireless Catalog published. number the biggest ever published. This first order for 12c in 'stamps or coin which may be deducted on was made possible by the big increase in of one dollar. Catalog not sent otherwise. This catalog costs us advertising during the past few months. twice the price of other catalogs. You can help the work along and make the tell magazine still larger and better, if you will Everything in wireless worth 'while is listed in this catalog. The experienced amateur will you to see our catalog before buying. You are thereby insured against an unwise purchase. It purchase what you need and the things you wireless apparatus. Xo bigger or is the Beacon Light to guide you right in the selection of your require in your work or for your pleasure, values are obtainable elsewhere. Send for revised price list. It is yours for the asking. better from the advertisers who are helping you. Read what they have to say in every issue, THE WILLIAM B. DUCK CO., 230-232 Superior St., Toledo, Ohio and when you want anything, no matter what it is, look it up in the advertising columns of the "E.E." and send your or- ders to those firms who are helping give you a magazine that you would not want to do without. MAGNETIC THE F-F BATTERY BOOSTER Live concerns that advertise sell better RECTIFIER For Home Charging and Service Stations goods and at a cheaper price, quality con- Patented April IS, 1916 sidered, than unknown firms who persist The wireless ban will soon be lifted, and it is time bushel." to figure what Rectifier you need to charge your bat- in "hiding their light under a Next for either S. C. or tery. The F-F Outfit is furnished month I will tell you the real reasons why D. C. current and attaches to any light socket, making quality of advertised article has a convenient, simple, economical, and reliable the any home charging situation. to be the very best and show you why you The battery must be charged often to main- should patronize your own advertisers for tain a high point of efficiency and keep the plates reason, if for no other. above the critical sulphation point. This will pro- this one long indefinitely their life and usefulness. Write for Bulletin No. 12. The France Manufacturing Company Cleveland, Ohio Advertising Manager. advertise! You benefit by mentioning the "Electrical Experimenter when -writing to 9 — May. 1919 ELECTRICAL EXPERIMENTER 79 PRACTICAL CHEMICAL Mesco Telegraph EXPERIMENTS Drakes *2«L Books 34) For Home Study Practice Set way i ui, for the big For Learning Telegraph Codes dnc b Mucily elast moms —-the amount ri when tub fat pa) ' to tension. In the case of wool that has Written ed and dyed, tl In non - technl- toroewl omjng i al language^ considerabl) firmer. If subjected to '• to read— the break lias the appearan :< •>.-.v.*/: to under- and rupture, >vVv^'i-' like a ! of a fracture, £v;w*v;&v;v.' I ' We will inclusive, Fig. R< ferrina r« #&«»•&•$W.jfifi lend any book new, fine, blue from Vttv";%*r>>«;*5S*l ' paid I clips. Notice the great var —keep them broken the tendency days — if of the fibers to split or tear lengthwise. The not en I irely i tale- fibers showing the side breaks are evidently return the books and your graph kej . without clrcuH n of the shoddy ma- money will be refunded in full. ugh pitch boner, one cell Red Baal Drj chine. Order direct from thm page. Use i ord Fig. HI i- ;i shoddy made frum new, fine, the coupon. ke3 .1 nil buzzer are mounted on worsted dips. Hen again may be ulghlj finished wood base, arid three ntcktl black Electrical Books plated binding posts are n that UM noticed their peculiar terminal fractures, Electric Motor Control Systems and r Ave different purposes. where the fiber has been pulled asunder. Prtcs Methods. Leatherette $1.50 fibers has a number of spines 342 Telegraph Practice Set, with Bat- One of the Electrical Tables and Engineering Data. ten sad Cord $3.24 ting from it. These so-called spines Leatherette 1.50 Motion Picture Operation. Leatherette.. 1. 50 Weighs 4 lbs. packed. are really the fiber cells, which, no doubt. Price does not include postage. Alternating Current. Leatherette 1.50 were loosened by the tension on the fibers Wiring Diagrams and Descriptions. OxnUiulion Pr«liCf S*l (or Iriininr, the Mof \r that and Leatherette 1 .50 a»l Audible CtaV. in the machine. Note both Figs. 9 MESCO Gssfa nsi Armature and Magnet Winding. 10 represent new wool that has been simply Leather- ette 1.50 at mechanically reduced to shoddy, and no Modern Electric Illumination. Leatherette 1.50 time carbonized. Modern Electrical Construction. Leather- ette 1.50 Fig. 11 is shoddy made from carbonized Electricians' Operating and Testing it seen what in- brown serge. Here may be Manual. Leatherette 1.50 dicates the brittle character of the fiber, de- Drake's Electrical Dictionary. Leatherette 1.50 void of elasticity. The breaks of the fibers Electric Motors. D and A. Leatherette.. 1.50 Electrical Measurements and Meter abrupt. Test- are seen to be quite ing. Leatherette 1.50 Fig. 12 is a shoddy made from brown Drake's Telephone Handbook. Leatherette 1 .50 serge that has been carbonized and subse- This outfit Is the only reliable iiistniment which Automobile Books will enal oi ersiors quently stript. The abrupt character of the tn the U S. Naval s with a buaxer and miniature lam breaks is plainly noticeable, while at the ' tn Ik>Uj mdil Automobile Igni- user master the vi-u«i and time the fibrils comprising the body same tion. Leatherette. List No. 52— Practice Set with Red Seal Bat- of the wool fiber are very distinct. Their $2.00 tery and Cord 14.05 PRACTICAL GAS attributed to the chemical Weigh* j tbs. packed. Price does not Include pottage- presence may be Brookes' Automo- AND OIL ENGINE of the stripping. bile Handbook. action HAND BOOK Send for the New Edition of Fig. 13 shows fibers made from blue serge Leatherette . .$2.00 that had been first carbonized, then stript. Automobile Start- Our Catalog W28 and afterwards dyed green. Here again we tng and Lighting. Leatherette ..$1.50 It Is pocket size, contains 264 pages, with over notice the tendency to break longitudinally, Ford Motor Car, 1.000 Illustrations, and des< rfbes In plain, clear terminal break occurs, the danguage all about Bells. Push Buttons. Batteries. and where a Truck and Tractor Telephone and Telegraph Material. Electric Toys. fibrils appear distinctly. Attachments. Cloth. Burglar and Fire Alarm Contrivances, Electric Call Bells. Electric Alarm Clocks. Medical Batteries. Fig. 14 is shoddy from the same batch $1.00 Motor Boat Horns. Electrically Heated Apparatus. Fig. 12. except that it has Battery Connectors. Switches. Battery Gauges. as that shown in Ford Motor Car. Ignition Supplies. Wireless Telegraph Instruments. been dyed a full red. Here we notice that , Truck and Tractor etc. one of the fillers has been split longitudinal- Attachments. J Leatherette fiber terminals .$1.50 Send for the Catalog Now ly, while the other three \ Automobile break characteristics that indicate the Cate- show chism and Repair Manhattan Electrical brittleness of the stock. Manual. Leatherette $1.25 Inc. Fig. 15 was originally a brown serge that Gas and Oil Engine Handbook. Cloth... 1.00 Supply Co.. Gas and Oil Engine Handbook. carbonized, then stript, after- Leather- ST. LOUIS: had been ette NEW YORK: CHICAGO: | .so i 17 Park Plar* 114 8 Wi - 81 I wards dyed a deep orange, and finally gar- San Francisco Off. e: 604 Mission St neted. A great majority of the breaks of Modern Language Courses fibers in this sample are extremely abrupt. French Without a There appears to be no longitudinal rup- Teacher, Spanish tures, and this seems to indicate little or Without a Teach- er. German With- no elasticity. Even the fibrils do not show out a Teacher. plainly. rofessor 16 is a shoddy made from brown Philip Schuyler serge that has been carbonized, stript and Allen. University dyed an olive shade. Here again we see of Chicago. An entirely new home the abrupt fractures of the fiber and a ten- series of modern dency to longitudinal splitting. The fibrils languages. are entirely wanting. Simplest. language 1" to-DUSter Fig. is a shoddy made from various method ever de- knit goods of different colors that were first French, The Electric Safety razor makes shaving a : carbonized, then stript. and afterwards dyed Spanish or Ger- vibrating 7,200 times a minute * man. Pocket pleasure. Blade blue, producing finished colors of varied cuts the beard smoothly and without slightest Bach $1.25 | lines. The fibers show a rather curious side pull or Irritation—feels like a tenth : without electric current. S Can be used with or abrasion ; a form of mutilation that ap- Mail the Coupon NOW quite in this lot of pears to be common Order on our Ave day money back plan. ai ism #f tic Lek-Tro-Shav jiuiweiitit — J shoddy. A barU-r say? 'Have shaved for years and have | Fig. 18 is a shoddy made from serges that FREDERICK J. DRAKE &. CO.. never used any shaving device near Its equal." g * ma user savs— i pleasing share I te were carbonized, stript and dyed a deep ma- 1009 Michigan Ave., Chicago, III. in hie. ShaTes my face closer than I id my | Enclosed find ($ ), for which please used to shave, but there is no after Irritation or ill I roon. It will be seen that the tendency of frum another razor." send me prepaid the books checked in this effects *s I usually get of the fibers is to split longitudinally. some I. No. I Made for use from Light Socket. adv. t«>r It is agreed that I No. 2 Made for use from Dry Battery. The terminal shown is characteristic of may return same in "> days if not entirely illustrated circular describing Lek-Tro- I Write for filer lengthwise, the Bed, and money will be refunded In full. Shav Safety Razor fully. a pulled apart when fibrils have a tendency to separate, forming Name VIBRATING ELECTRIC RAZOR CO. j Dept. 122. Omaha, Nebr. a brush-like head. Address J The various characteristics above re- benefit by mentioning the "Electrical Experimenter" when writing to advertisers. — : 80 ELECTRICAL EXPERIMENTER May, 1919 ferred to, and illustrated, will serve to draw attention to what one must look for 4I4.RAGES is believed in an examination of cloth that [-4S ILLUSTRATIONS to contain shoddy. In masses of shoddy such as are usually taken for microscopic WANTED I.C.S. examination, there will always be found ELECTRICAL ENGINEERS many short fibers due to mechanical break- HANDBOOK ing of long fibers, but to separate them is Immediately M an operation of great delicacy, tho yielding results no value. IELECTRICITY! of WIRELESS operators are in THE "BURNING" TEST demand owing to the expan- HERE'S just the book on Vegetable fibers may be readily distin- sion of our Merchant Marine. Electricity that you need guished from animal fibers by burning. Pay has increased to $110 per to answer your many ques- Animal fibers, such as Wool and Silk month plus all expenses. tions — to solve your knotty give off the smell of burnt horn. They problems, to teach you new kinks, V. M. C. A. Radio Schools do not fire like vegetable fibers, but cease THE to be your memory for tables, rules, give thorough practical courses formulas and other Electrical and to burn when removed from the flame, individual instruction. Our Mechanical facts that some people and the burnt portion curls up, forming a with try to carry in their heads—and fail. graduates fill responsible posi- hard cinder at the end of the thread. tions. With this "Little Giant" I. C. S. Vegetable fibers, on the other hand, give Electrical Engineer's Handbook in off a slight smell of burnt wood when your pocket, toolchest, on your is your opportunity. drawing table ordesk, ignited. They burn away very rapidly THIS work bench, Classes now forming. Excel- an hour or a day need not be lost with a flash, leaving no hard cinder, but "digging up" some forgotten rule, some un- lent dormitory facilities. Complete a white or gray ash only. The above familiar fact; you'll just turn to the very com- laboratory equipment. Write to- it "in a jiffy." Just a few tests broadly distinguish vegetable from plete index and get day for illustrated booklet. of the subjects treated are: animal fibers, but further chemical exam- Electricity and Magnetism; Electrical Sym- ination is necessary to distinguish mix- bols; Batteries; Circuits; Magnets; Direct and tures of any of them when woven into Alternating Currents; Dynamos and Motors; Y. M. C. A. 19.) Belts; Shafting; Electroplating; Electrical cloth. (See Fig. Measurements; Meters; Arc and Incandescent Referring again to Figs. 1 (Cotton) and NEW YORK CITY Lamps; Mercury Arc Rectifiers; Transformers; 4 ( Linen) we can readily distinguish the Insulation; Electric Cars; Single and Multiple* Manhattan Branch Brooklyn Branch: Unit Control; Transmission; Rail Welding; difference by means of the microscope as 154 East S6th St. Marcy Ave. Near B'way of Wires — Sizes, Capacities, etc., fabric is without starch, oil Tables shown. If the Tel. Lenox 6051 TeL. Wmsburg 3800 Mathematical Rules; Formulas, Symbols; Tables makes linen translucent and cotton Constants, Equivalents, Roots, Powers, Re- of of ciprocals, Areas, Weights and Mea sures; opaque. The finish must be washed out Chemistry; Properties of Metals; Principles of highly finished materials before this test Mechanics; First Aid, etc. can be used. The Electrical Engineer's Handbook is one of 52 A test to distinguish between linen and I. C. S. Handbooks covering 22 Technical, Scientific and CHEMICALS Commercial subjects. (See titles in coupon below.) cotton, which only an expert, or at least a have the contents of a full-size book condensed tor EXPERIAXtNTI They quite experience, can I THE Into pocket-size ready to go with you anywhere and person having some be at your instant command. Substantially bound in perform, consists of what is known as the (ON'T PAY FANCY PRICES for cloth, red edges, goldleaf stamping, printed from new, chemicals. Buy highest quality for low- clear, on good quality book paper and "tearing" test. The linen weaves in general readable type est price. Our unique system of standardization Illustrated wherever a picture willbelp. are more difficult to tear than cotton. The guarantees you at all times the most for your torn ends of the linen threads appear un- money. Send today for interesting free booklet No Risk Money- Back Offer! describing the money-saving, value-giving, N-S even in length and the individual libers are The price of the famous I. C. S. Handbooks, of which plan and listing hundreds of chemicals, chem- in practical more than 2,000,000 have been sold and are twisted in every direction. The sound of ical glass ware, and apparatus. everyday use, is $1 per copy. So confident are we that you will find them exactly what you need for tearing linen is shrill, and that of cotton ready reference in your work, that we stand ready to dull or muffled. THIS RELIABLE MAIL ORDER HOUSE promptly and cheerfully refund your money if for any norld (lined (<•' in "irrles* (elccnph apparaiui ind eipen- hundred* I't reason yuu are not fully satisfied with their value. distinguish between the ten luppl. , hii been ur^td bj of patrons to easy way to < An .rr> depart In offer whit >li>h . cher mem unnrwc Simply send a letter or the coupon below, enclosing $1 Cotton Damask bdfa ul chen for each book wanted. If at anytime within 10 days you highly-sized and calendered .'here you ire jI»ih inured o( Standard Quatttj, Standard Qnaatitj, Standard Pithnf. Standard frit*. wish to return the books, your money will be refunded. and true Linen Damask is to boil a sample. THE NEWMAN-STERN CO. INTERNATIONAL CORRESPONDENCE SCHOOLS After being dried and ironed, if it is cotton Dcr^'imeoi E E CLEVELAND. O. ton, Box 6187 Scran Pa. it will have a dull and somewhat fuccy - -TEAR OUT HERE- appearance, while the luster and smoothness OhaTUminrtfinvSta'vTt S/y/»ta/m/ INTERNATIONAL CORRESPONDENCE SCHOOLS of real linen will not be affeeted by this Box 6187,SCRANT0N,PA. treatment. Mercerised Cotton Damask apparatus, Raw keeps more luster than untreated cotton. WIRELESS Materials, Magnet I enclose $ for which send me postpaid the Handbooks marked X, at $1.00 each. I may return any or but less than linen. wires, motors, experimenters' needs, novelties all and get my money back within ten days from receipt: Since the price of pure, new wool is rel- listed in our Catalogue C-3. Assure yourself Electrical Engineer's D Advertiser's prices buying B Teleph.andTeiee.Eoglneer*8D Business Mnn's atively high, it is the practise of manufac- of prompt service and right by Mechanic's D Bookkeeper's D turers to mix other materials with it, the from this world famed, reliable, experi- D Steam Engineer's C Steno. ami Correspondent*! G Westinghouse Air Brake Salesman's most common of which is "Shoddy." Such menters' Supply House. M Civil Engineer's Q Window Trimmer's U Coal Miner's Cotton Textile Worker's goods have many uses, being a full-bodied, The Newman-Stern Co., Cleveland, O. Concrete Engineer's Farmer's flimsy fabric, it is made chiefly into Building Trades Q Poultryman's but H Plumber's and Fitter's Marine cheap cloth, table covers, etc. Manufactur- Chemist's Automobiles "The Livest Catalog in America' ers state that the best grade of worsted Our big, new electrical cyclopedia shoddy—that having long fibers—is superior No. 20 is waiting for you. Posi- grade, short staple, new or virgin tively the most complete Wire- to a low catalog Street less and electrical in it is impossible to get the print today. 180 Big Pages, and No.. wool ; also that 500 illustrations. 300 in texture and finish required for some of the struments and appara- City_ best grade goods without the use of some tus, etc. Big "Treati: on Wireless Teleg- jv- rniir „, to the fact that shoddy is raphy." « shoddy. Owing -<'^EE jjPJtTPJ* to 20 coupons for l" our ~*^^^Jk\\mm\m\-M,BBBBMZ ~i,-nrv from wool fibers, as stated under the J fc sons FREE made i - a e p g ^3E r!JrmJ^ Cyclopr. i "Shoddy," it is very difficult to de- F It F F ^rm#jC^ heading dia No. 2 Telegraph Pictures Vi !.: a convi < >m RANSFORMERS and wool i solution of Potash ui • austii Soda into which is i 8 Volt Secondary 1 111 mi ed .i lampti ol the wool to be LISTEN tested. A precipitat indicates the relative amount "i cotton and other sni i I is Hill DOt ft ikew ite when i otton imn Itirl.T in an at id, the precipitai will show tl TO uvc amiiiint ui adulterant Fig. 7. $1 .oo It is easy to determine heavily-weighted silk material by burning a small -ample Postpaid silk lniriis Pure rapidly, nulls like » I, ME! Only $1.00 | gin* 3 and produces a small amount of brittle, run. r 12 and 18 Tolls s«Nm test for lead will iiadiK reveal its pi - ®)S :£. QUESTIONS AND ANSWERS ^iii. Be A Ques. No. 5. Edward I. Walsh, Lexing- CERTIFICATED ton. Ky., wants to know how he can remove Thi-t coupler 'It. I real work an-t "mad« lOod rhe l>ll I Irdec rour La u i lodin stains from li^ht clothing. NOW for future delivery. Later there i- bound U3 be a rush, result: delay. A email deposit will Insure Ans. You fail to state whether the ma- ELECTRICIAN delivery nheo you »im it. terial from which you desire to remove the J. F. ARNOLD is is stains starched or unstarched. This THIS IS YOUR 2082 Lexington Ave., near 125th St., N. Y. an important factor. Stams which are pres Established 1910 cut in unstarched material produce a brown CHANCE OF A LIFE TIME or yellow stain. Whereas on starched ma- I am Chief Engineer of the great Not Toys But Real Apparatus nginerring Works. I am in close official touch with the electrical world. I On same as used by aU operating com] You had better send us your order Immediately know how badly we need trained electri- to Insure prompt delivery, ;i< this equipment cians who can lake charge of important Hill not last long at these i work as experts. Kiuht now there is such 110 Volt Hand Generators ... 3 bars, each $3.00 a need for executive 4 bars, each 4.00 electricians that I am 5 or 6 bars, each 5.00 making a special effort to help meet the Telephone transmitters with arms. each.. .75 demand. I am publishing this special an- Good ringers complete with bells, each 50 nouncement to secure a certain of Telephone receivers, each 75 number ' ambitious I will Condensers. 2 to 2 M.F., each 50 men whom personally Induction coils, each 50 train by mail for the wonderful oppor- Relays, each 1 .50 tunities that are open. Repeating coils, each 2.00 Real complete C.B. wall type telephone... 4.50 Slightly used dry cells, per dozen 1.25 / WILL MAKE YOU send money-order oi cash with yotu order Mv*l Please ELECTRICAL SPECIALTY COMPANY a Trained Electrician Dept_E, 48-50 So. Front St.. Columbus, Ohio I don't care Dept E," 128 So llth'St, Philadelphia, Pa. how young or old you are, just as long as you can read and write and have a spark of ambition. I don't care where you live or what you do. I don't ??????? care if you don't know a blessed thing about electricity. Just give me a little of Will Your Station Be Ready your spare time for a short period and I'll ??????? show you the quick way to success in electricity. You can qualify to earn $36 ALL AMATEURS WILL CELE- -.-, LT-s-' ~4aaaaai to $100 a week with opportunities for BRATE O PEN 1 N G NIGHT. OVERHAUL YOUR STATION greater earnings. NOW. DON'T DELAY. / Train You by WRITE FOR DESCRIPTIVE BUL- Fig. 21. Removing lodln Stains from Light Mail! LETIN .tin! proposition on supers or Other Colored Cloths By Application of Your spare time will do. No interfer- live receiving apparatus, smooth running Ammonia. The Ammonia May Be Applied knobs, levers, switches, con- ence with your regular duties. I under- rheostats, With a Glass Rod or Sponge, and Should tacts, etc. stand just what Be Immediately Washed Out as Soon as you must know and I have devised a wonderful way of instruct- Audiotron Sales Co. the lodin Stain Is Removed. ing by mail. I positively guarantee your Leavenworth St. San Francisco 1940 satisfaction. tcrials, the presence of starch causes the Wonderful stain to become deep blue or black. For unstarched stains, sponging with Electrical MARKO Ammonia, or alcohol, the latter being fre- Fr Outfit quently used on materials which water Absolutely free. Not a penny STORAGE BATTERIES would injure. See Fig. 21. cost to ARE GOOD -TRY ONE you now or later. To those who act at Starch, such as prepared for laundry pur- once I will give a wonderful set of Elec- Paul M. Marko & Co., Inc. poses may be used for washable materials. trical Equipment with my compliments 1402-1412 Atlantic Ave. Immerse the stained parts in the starch and Brooklyn. N. Y. Write me at once. I have only a limited boil. It first turns blue and then disappears. number of sets to be given free. Drop Flour may be used in the same manner as me a post card or letter. the starch. 1 '" ' ,J U w '" have to act quick to WIRELESS TELEGRAPHY For starched materials, the stains may be Vrf*!/WW HIV,!? get j n on th; s opportunity. :>nr 14 weeks course prepares you for MERCHANT immersed in a dilute solution of Sodium \\ rite me today for lull particulars. Drop M.\ltl\E paying Sllu per month and Mi me a post card. Write Now. RADIO INSPECTORS recelre 11.200 i" 13.50a per thiosulfate (known photographically as year. Our Instructors are licensed by D a envem- of "Hypo"! and then rinsed thoroly. Sodium CHIEF ENGINEER COOKE, ment : school fullv equipped and largest Its kind ui inail and payable weosiy We sulfite (not sulfate) may be used in the Chicago Engineering Works, guarantee to qualify you. Board and room In Wash- ington at reasonable rates while taking the same manner as the thiosulfate. Another Dept. 525 RADIO SCHOOL. Particulars on request. SERVICE method is to soak the stains in dilute am- 102 Pa. Ave. N. W.. Washington. D. C. 441 Cass Street, Chicago, Illinois monia (sp. gr. 0.95) until they disappear. L You benefit by mentioning the "Electrical Experimenter" uhen writing iV advertisers. c May, 1919 82 ELECTRICAL EXPERIMENTER HOW THE FRENCH LOCATED SUBMARINES. Super -Sensitive Microphone ?™^q Just to Get Acquainted This instrument is offered * I (Continued from page 9) at an extremely low price. I will mail 4 issues of major problems, if not indeed the pre- we vou It is excellent for building your own amplifier. Can also be used in dominant one, to be met with in working many experiments where a sensi- out a more selective and accurate form of THE tive microphone is required. submarine listening device was that, what- PHOTO-PLAY Detectagraph, ever its form, it should be susceptible of operating and functioning on any vessel detecting instrument WORLD it under full headway, and fur- of marvelous sensitivity can while was oe used for detecting secret ther, that the indications given by the in- The one by which all others conversations. Outfit consists strument of the direction of such sounds of Sensitive Transmitter. 25- - should be sufficiently accurate to permit the are governed for $1.00 ft. Black Cord, Receiver, Headband, Case and Battery. commander of the vessel on which it was The Photo-Play World contains Send for One Today and installed to set a straight course for the $15 Convince Yourself. Deteclagrtpb indicated spot where the submarine lay in only the best pictures— Stories THE $15' MICROPHO wait for its prey. Contrary to general and Articles. Has a Staff of DEAF-PHONE opinion, many authentic instances are on America's Foremost Writers. is a super-sensitive instru- record where submarines were surprised in been devel- ment which has this way during the war and sent to the Subscribe Now oped to meet the demands bottom, sometimes by armed merchantmen for a practical and efficient 35c a Copy $3.50 a Year hearing device at an extreme- or converted yachts, and again by fast de- ly low price. It is equal to stroyers or submarines. The English in any $35 instrument made and grati- THE PHOTO-PLAY WORLD upenur to most of them. The outfit consists of One particular seem to have obtained very One Super-Sensitive Transmitter with cord connector; fying results in fighting the U-Boats with Bulletin Bldg. Dept. E. E. Philadelphia, Pa. Super-Sensitive Ear Piece with small black cord; One Black Single Headband; Black Case and Two Bat- their own submarines. teries. WRITE TODAY FOR FREE BOOKLET Lieut. Walser designed his apparatus G. BOISSONNAULT CO. after first carefully studying a well known, 26 CORTLANDT STREET NEW YORK yet heretofore overlooked, principle of phy- Makers of Super-Sensitivt Microphone Apparatus Yankee Wireless 50 sics, viz : that sound, identical to light, upon passing thru one medium into another, is refracted. The orthodox theory concerning THE YANKEE Experimenters — Man ufacturers I the complex light beam or ray from a ii lor two complete stations -with Morse code and instruc- tion! lot operating. We will also include our picture tiile given object states that they comprise a attachment, which will enable the nrwrtt ir 10 lend and re BASES — INSULATION wirelcu The c. waves, which may be e obtained only (i number of component All charges paid for 50c money order considered as parallel when their source is A. A B. HFC. CO.. 1305 Peoria St., CVcuo. QL composition situated a sufficient distance, and which ™JJ I base suitable for detector, fixed con- parallelism is upset only when an obstruc- CLEARTONE PHONOGRAPHS their path, they are denser, etc. The bottom has a cavity tion is placed in when $4.00 to $200.00 Retail 3" " x %". Over all dimensions thus caused to enter a new medium having Needles 45c per thousand in lots of 500,000 x 1V2 Motors $1.35 to $14.75 each. Tone Arms and different value that in 4Vi" x 2" x %"• Two holes for bind- a density of a from Reproducers $1.30 to $5.75 per set. Main fastening down which they were propagated. Lieut. Walser Springs 20c to 00c each. Records, Needles. ing posts and two for Sapphire Points and Parts at reasonable to table. Post paid 30c had the forethought to perceive that sound prices. waves must follow the same theory. To Write for our S4 page catalogue, the only one — pf Its kind in America, illustrating 33 differ- An excellent Base prove his theory, he interposed in the path ent styles or Talking Machines and over 500 Phonographic Parts. f different H or detectors. of sound waves a device which would re- LUCKY 13 PHONOGRAPH COMPANY Has binding post holes and holes for spond to various vibrations, and which Export Dept, 46B E. 12th St.. N. Y., U.S.A. mounting detector parts. Black com- formed what we might term an acoustic KMBiNi&Klft^nlLLgJWB position 3%"x2"x%". Post paid, 32c lens. As has been found in explaining the BIG MONEY SAVINGS FOR YOU Manufacturers Send for Discounts in theory of light transmission, a similar ef- Used and""rebuilt motorcycles, si rifle and twins, Quantity. takes place in sound transmission thru to $100. Uaed bicycles. $5.00; tan- fect dems, (10. AH machines guaranteed Bakelite panels, about the air or water and other mediums, and in good working order. New bi- 9 x 19 x Black XX $4.00 cycles and motorcycles at Fac- Vi the result of thus interposing such an acou- tory prices. You save dealers' 19 x 19 x V* Black XX 8.00 profits. Motorcycle and auto- Black 3.00 stic lens or vibrating member causes the mobile tires too. $3.00. Com plot* 9x19x316 XX „ line of parts and supplies. 19 x 19 x 316 Black XX 6.00 individual waves composing the complex Deninger Cycle Co. . Rochester, N.Y, A. H. CORWIN & CO. wave propagated from a given source to nMMmtan This has the two-fold 5 Kirk Place Newark, N. J. come to a focus. fn« • • Get upup-to-to date Intn House Wm-m intensifying the individual waves M lA/vrwiA«rt«%A INC ! Save Time. Mon:"dONEY, effect of i IV I IPf^ Tri f^l ft Ii S I *BO« and MATERIALby USusing LH^V^LI lV^iaHO our 98 GENl, INE blue.__ PRINTi-r and also of isolating them precisely from Drawings, containing; all the latest diagrams and connections known in house wiring—every diagram other sounds emanating from the sources and connection up-to-the-minute as uaed by first class electricians for wiring Bells, Burglar Alarms. Lights, Annunciators. Fire foreign to the one being localized. Natur- Alarms and Electric Gas Lighting. These drawings are bound in the TELEGRAPHY form of a flexible book (9x121 for convenience in using on the job. will ally, the different sources of sound Send for them, and if they don't make you more efficient aea wireman contractor, return them and number of foci, of and save you many times their coat aa a AND RADIO create a corresponding money will be refunded—you can't afford to be without them. One DAY ANDEVENINGCLASSES which the geometric focus can be ascer- Dollar postpaid. Send for circulars on other sets of drawings. SEND FOR PROSPECTUS computation. In a PATENT SPECIALTY COMPANY tained by mathematical P. O. Box No. 583 San Franci»co, Cal. IN SUBJECT INTERESTED the similar manner from the position of Combination A. C. and D. C. EASTERN RADIO INSTITUTE sound focus which corresponds to any in- 899-B Boylston St. Boston, Mass. dividual source of sound, the definite direc- Eight Inch DESK FAN tion of that source can be readily estimated. detachable plug and 8 ft. of cord. Will operate on A.C. or D.C. current, The accompanying illustrations show the 125 volts. 30 to 60 cycles; Send 100 to BUY gear in- weight 10 lbs.: black enamel finish: "Walser submarine detector" as fan for height IIV2 in. A real —not a NOW stalled on French vessels, and the detail toy. Price $6.50. Agents wanted. Lata- view shows how the sound detecting lenses, loguc and THE TEWNO CO. which are fitted into large steel bulges or PRACTICAL WIRELESS TELEGRAPHY Save a 150 Chambers St.. New York "blisters", secured to the hull of the vessel, By E. E. Bucher rY^ll-*-UOllar and THE WIRELESS AGE for one year, are connected to two trumpets, which may- MATHEMATICS MADE EASY $2.75. Regular price, $3.75. be traversed in a circle above them, so as to The Arcascope— the Combination Triangle WIRELESS PRESS. INC.. 33 ELM ST.. NEW YORK. heard with a Brain —will multiply, divide, fliure accurately localize the various sounds percentage and proportion, solve all problems from different vibrating diaframs compris- in trigonometry and geometry, draw symmetri- AMATEURS ATTENTION! cal figures, plot arcs, etc. Superior to any slide ing the lenses. One trumpet picks up and rule. Simple to operate. Also includes a With our No. 5A receiving set. consisting of double and localizes the sounds from the port lens, and TRANSPARENT TRIANGLE, PROTRACTOR slide, tuner, galena detector, fixed condenser, switch THREE RULES. Used at Columbia University. for aerial, ground and receivers and binding posts the other the sounds picked up and in- West Point. LT. S. Aeronautic Schools, etc. Only mounted on beautifully finished quartered oak base, Postpaid. Order today before you forget. lens. spheri- cents shore stations and ships at sea come in with surpris- tensified by the starboard The Ogden, Utah Send Dept. S, L. J. LEISHMAN CO.. ing clearness. Price $4.50. Receivers 75c up. cal segments supporting the multiplicity of 25c for set of 3 rubber knobs 1" dia. suitable for loose- ON THE coupler switch knobs, detector handles, etc. 5c in lenses is indicated by A in the detail figure. GET stamps brings copy of code. This segment is provided with a circular VAUDEVILLE McMAHON & ST. JOHN. STAGE profession for 56 West Ave., So. Norwalk. Conn. series of openings, B, each of which con- I tell you how. Fascinating Big salaries. Experience un- tains a sensitive vibrating diafram, C. The either sex. necessary. Splendid engagements always general effect of this arrangement is to waiting. Opportunity for travel. Thea- authorities endorse my Printing* Cheap focus all of the sounds picked up, the focal trical agents and *s~~Canis.circular8, labels.book. paper. Press$6. methods. Thirty years' experience as points all lying on a circle, /. As afore- 2^g You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. EXPERIMENTER 83 M ay. 1919 ELECTRICAL ' and oni keel. .'" Tobacco Habit solid sound - in, in which Mil. m in tht op i the BANISHED appa 48 to72 HOW'S ia such thai thi hi with the li of two car trumpets, D, in the diai ram, an] the la quickly No crnvinjc for tobacco in any form thru when you begin taktOffTobaceo Redeemer, up and localized for dirt V Don't try to Quit tlu* wobAoeo hublt un- ds from thi- V ftJdwl I t'liaioaing/ fight against heavy odds ns the other the starboard lent. and means n to-runi* bocK ' and Let tho tobacco habit quit YOU. By means of the itinj drum, It v. ill quit you, if you will just take appi • Tobacco Redeemer, according to direc- I which aid drum beii tion* for two or thn-«* day*. It id a moat erator, the | reliable ilrtmi mitrvilouwly quick and thoroughly I. rated. SO that as the handle "i the I remedy for the tobacco hatnt. I is turned the trumpet ASK YOUR BOSS circles ; focal Substitute aboul tl live I Not a any sounds received, The control drum, ''Docs it Pair to Tobacco Redeemer contains no hubit- of re- forming drugs of any kind, It is in no sense which is manipulated bj the operator, a milirttittite for tobacco. After finishing volves the trumpets, P. which arc pivoted the treatmentyouhavoabsolutely i t"'l<. i |lr " the movement, //. J to use tobacco aifain or to continue the qm on a ! l which bj of the remedy. It makes not a particle of represents the counterweight, who difference how lonff you have been using means of cord, A', maintains the trumpet in Put it up to the man tobacco, how much you use or in what form you. Don't hesitate. He'll I such a position that its axis is always employs you ure it— whether you smoke cigars, appreciate your interest fine cut or pointed toward the center of the spherical respect and cigarettes, pipe, chew plug or and 11 positiTe- knows the value of training— use snuff. Tobacco Redeemer wi I lenses. The function of the counterweight, He ly banish every trace of desire in from 48 will gladly tell you how much more /.. is to maintain the balance of the movable to 72 hours. This we absolutely guarantee you would be worth to him as a in every cose or money refunded. on which the trumpet is supported, showing I trained worker. If you're in doubt Write today for our free booklet while the weights, .1/. .1/'. cause this arm the deadly effectof tobacco upon the human 1 ASK THE BOSS. Ask him anyway. , in such system and positive proof that Tobacco filiate about thi V, A' Redeemcrwillquickly free you of the habit. rolling of the vessel is position :l way that the A Bigger Job The Newell Pharmacal Company, i thus tending to keep the In Tour Factory you d like 1 St. Louis, Dept. 52 Mo. tlie trumpet in the same hori- mouth of most in your factory ia not beyond at all tunes. The complete zontal plane your reach. You can get that position is carried by the metal frame apparatus any time you will fit yourself for it. marked O. Aim as high as you like and you will With the apparatus in use, the operator find that American School training TABLETS hears the sound with the greatest intensity will enable you to qualify for the job and sharpness when the trumpet axis is in you want. KNOWING HOW doubles and FOR trebles your earning power. If you don't line with the locus of that particular sound. think so-ASK THE BOSS. He can also hear a certain sound when the trumpet is anywhere in the vicinity of the Why Not fry This All focal point. The operator proceeds in any event to explore the various foci by manip- Guaranteed Training ulating the central control drum, which re- The American School training Pain volves the trumpets around the focal cir- is so thorough, complete and up-to- cles. This centralized control drum having the-minute that it absolutely guaran- Headaches been calihrated beforehand, it becomes a tees satisfaction or your money back. simple matter for the observer to accurately In other words, you can take ten full Neuralgias locate the direction of a certain sound, examinations in the Course you select. progressing— or more strictly speaking,— its origin, as Then, if you feel you are not will not enable you to has manipulated the trumpet to that the instruction Colds and La Grippe soon as he advance — you simply notify us and your the proper focal setting, so as to hear the money will be refunded in full. The success Women's Aches and Ills received sound with -the greatest intensity of our thousands of students warrants this confidence in our ability to fit you for a bet- Sciatic Pains clarity. a quick calculation based Rheumatic and and By ter paid and more congenial position. upon the value of the minimum intensity ol Tablets Ask y°ur Druggist for A'K the sound received, the range of the sub- TRAINING Decides Tour Pay (If he cannot supply you, write us) marine can be approximately calculated. It Make sure of this: the who get more money in is then a comparatively simple matter to men yojrfactory than you do know Small Size dmrJjk Dozen Size steer a straight course for this spot, and if more. Your position and pay I and in any job, is the object of the search turns out to be a I at all times, I simply by what you submarine, then the destroyer will pass over governed — 25c can DO. And that depends on lOc' ^^ ^^ Fac-Similo W it. ______it and discharge depth bombs upon what you KNOW. Make some of vour spare time bring SUC- on the Genuine Of course the wiseacre will say. it is all See Monogram Jj^ CESS to vou. Study in idle very well to locate a submarine and then moments with GUARANTEED TRAINING. The Aatiksmma Remedy Company. St. Louis, Mo. steering a course so indicated for the object Make your start TODAY for a better job by and mailing the coupon. Free Write for Free Samples of dropping several carloads of "ash cans" checking Bulletin and full details will be promptly (depth bombs, in navy vernacular ) upon it, mailed you without any obligation. LEARN HOW TO BREATHE-RITE FOR but what about the movements of the U- HEALTH "Snorenomor." Boat, which may have paddled off a mile AMERICAN SCHOOL or so from the spot so dear to the heart of Or COBBESPONDENCE the naval officer. This problem would seem Dept. G 7445 CHICAGO. U. S. A. solved by the fact that contrary to BB______a i i T'l Uijp the usual apparatus utilized for such pur- Explain how I can qualify the operator may keep _1_SC for the position checked. * II 11 Mouth on taking the soundings of the sub- ...High School Graduate ..-Lawyer Hr. lUMf* full head- Inhale marine, while the vessel is under ...Electrical Engineer ...-Business Manager virateot Public Accountant K.rm". way and moving loward it. The sensa- „Elec. Light & Power Supt Certified »nd «rc ID ..Hydroelectric Engineer ...-Accountant and Auditor eoaatant tions experienced by the submarine detec- ...Telephone Engineer Bookkeeper 12.00 cubby- At Best Supply Houses or sent direct tor tion officer located in bis steel-bound ...Telegraph Engineer ...Stenographer Expert wn near the keel of the on-rushing ...Wireless Operator ..Fire Insurance CO., Dept. 2, Ann Arbor, Mich. ...Sanitary Engineer BREATHE-RITE , Architect vessel, as the sound of the submarine's en- ..Building Contractor ...Master Plumber Engineer and propellers pound louder and Civil Engineer Hang and Vent. ...Automobile Engineer louder in bis ear trumpets, probably can ...Structural Engineer Engineer .Automobile Repairman PHOTO CRAFT than described, for the ...Mechanical be better imagined ....Airplane Mechanic PHOTOGRAPHIC JOURNAL . Shop Superintendent THE NEW submarine commander may have a "card Steam Engineer General Education Course the Art of Picture Taking and and Designer Common School Branches Devoted to up his sleeve" and be just altout scrappy ...Draftsman Nature Work with the Camera. clever enough to lay for the on-coming Four Competitions with Valuable Cash Prizes and Leading to a Fifth. destroyer or war vessel and discharge a subscription. Send 10c for three months' trial torpedo at it or open up with a broadside Photo Craft Magazine, Ann Arbor, Mich. from some nifty "seven inchers." advertiser You benefit by mentioning the -Electrical Experimenter' when writing to 84 ELECTRICAL EXPERIMENTER May, 1919 H.P., 110 volts, A.C. THE THOUGHT 1 60 cycle, single RECORDER phase, 1 750 R.P.M. (Continued from page 12) ent upon wave motion, it should not be sur- MoToRS prising therefore that thoughts or active We have 1000 NEW WASHING MACHINE MOTORS. These thinking should give rise to wave motion are of standard manufacture and carry the regular factory guarantee. Shipped in original boxes. Complete as cut. as well. This theory is greatly strengthened by the fr.om Bankruptcy Stock Bought fact that it has been proven beyond doubt Suitable for operating Coffee Grinders, Cream Seperajors, Bottle Washers, that active thinking necessitates an expendi- Air Compressors ture of energy. If you sit perfectly quiet Small Lathes, Mail $3.00 cash or in a chair without expending any visible Etc. Money Order. We will send CO.D. subject muscular energy, and if you concentrate to full examination. $18-50 very hard upon a certain problem, it is not MONEY BACK GUARANTEE *V EACH infrequent that perspiration appears on Special Quantity Prices Regular Value S34 MANUFACTURERS" DISTRIBUTER your forehead from the simple effort of BARGAINS In Small Motors thinking. Of course, this is rather a com- and Generators GHAS. H. JOHNSTON - West End - Pittsburgh, Pa. Write lor Cataluo plex phenomenon, as the perspiration is not produced directly, but rather indirectly by the nerve centers working upon the human organs, principally the heart. Nevertheless, we know that thinking proper calls for an expenditure of energy in the brain itself. That this energy is considerable can also be 4 Famous Books! shown experimentally. It therefore cannot come as a surprise that the act of thinking should give rise to a direct wave motion, sending out from the brain certain waves in an analogous man- ner, to the spoken word which produces sound waves of a certain wave length. It is quite probable, however, that thought waves are simply another form of ether EACH ONE waves, the same as radio waves or light waves. Just as light rays traverse thru a A BIG thick glass pane without suffering any ap- preciable loss, just so will thought waves probably pass readily thru the human skull. If once we admit this theory it follows that it should be possible to detect such waves, and the only thing we need to know about them are the wave length and other impor- tant characteristics. We may take it for granted that the human brain, sensitive as THE it is, probably is not at all sensitive to these waves, and that by suitable apparatus it BOOKS should become possible to detect such waves. YOU Just what apparatus are necessary to de- tect thought waves, or the effects therefrom, MUST the writer does not venture to predict, but HAVE there is no doubt that the apparatus will be eventually found. Very little is known about the emission of the thought waves, and as a matter of fact the entire mechan- ism which produces thoughts is practically an unknown quantity, but every effect can be translated and recorded if once we understand its fundamentals. Thus, fifty years ago the recordinc of the voice would have appeared just as fantastic as the recording of thought appears today. People then rightly said, how could it be possible to hold the spoken word ; it goes Elec- No. 1. How to Make Wire- Wireless Course in 20 Experimental into the air and vanishes instantly. But less Sending Apparatus Lessons tricity Course in 20 once acoustics were better understood, it 2. to Wire- By S. Gernsback. A. Lescarboura and Lessons No. How Make became a simple matter for the inventor of H. W. Secor. E. E. less Receiving Apparatus the phonograph to record the voice. Simi- ByS. Gernsbackand H. W. Secor. E.E. A course that tells you everything By 20 Radio Experts. larly, the day will come when thoughts will you can possibly want to know about A Course of the theory and prac- off in lesson No. Remarkable Books be recorded in an analogous manner. All "Wireless" starting tice of Electricity for the Experi- Two 1 by explaining the Principles of undoubtedly one menters. This is Book No. 1 contains 100 pages, that is necessary, as stated above, is suitable Electricity. second and third The of the most complete ajid com- size 7 x 5 in. and 88 illustrations, lessons are devoted to magnetism, prehensive treatises of this special paper bound. apparatus, and this should be easy to find. motors, generators and wiring. And book subject ever published. The Book No. 2 contains 100 pages, then, by simple, easy stages, this authors as suggesting the audion as a is written by the same size in. and 00 illustrations. The writer, in wonderful Course takes you into in 7x5 the famous "Wireless Course paper bound. thought-wave detector, does not do so be- "Wireless". The mysteries of "Wire- 20 Lessons". less" are unfolded to you by the These two books have been written cause he thinks that it is suitable in all re- use of such simple** language s.i skill- Even- phase of experimental elec- and published entirely for the wire- is fully used that of necessity you must trici y is treated comprehensively less enthusiast who wants to make spects, or even feasible. His main idea every word The subject in plain English. 1' is a book not They understand his own radio apparata. to set the stone rolling, and get other people is not treated superficially, however, only for the beginner but for every contain more information on how experimenter and student <>i Elec- for there is a whole leison devoted to make it than any other books to think about the problem, when sooner or New Experiments are de- to the Theory and Mathematics of tricity. we know of. Only strictly modern The this epoch marking subject. To lend scribed and explained and nearly radio apparata are described In later something surely will emerge. charm to the Course, the last lesson every application of Electricity In these books and the illustrations writer has suggested the audion because it (No. 20) is devoted to a history of modern life is given in simple and descriptions are so clear and Wireless and the men who developed language. simple that no trouble will be ex- is known as one of the most sensitive elec- it. perienced in making the instru- trical detecting apparatus for wave motion The book ron+atns P"t nages and ments. Size of book Is x IO'/ In.. 160 rise 7 4 more than 400 Illustrations. which we have today. If thoughts give pages, 350 Illustrations, 30 tables. Br>ok No. I —How to make Wireless Sending Apparatus 25c to electrical waves, then by winding a few Flexible cloth cover. . per copy $.50 Flexible cloth cover. .. per copy $.50 Stiff Book No. 2 How to make Wireless slipping it Stiff cloth cover per copy 1.00 cloth cover per copy 1.00 — turns of wire on a headband and Receiving Aonaratus -25c Postpaid Postpaid Postpaid over the head, it should be possible to de- tect the presence of thought waves in the hand, too. the audion THE EXPERIMENTER PUBL. CO. Book Dept. 233 Fulton St., New York audion. On the other is enormously sensitive to capacity effects, You benefit by ntioning the "Electrical Experimenter" when writing to advertisers. May, 1919 ELECTRICAL EXPERIMENTER 85 as i- well known. Thus, fur instance-, an scillating audirni is to tenaitive tliat •. /Aake All This the human baud is approached to i< at a Come True distance of even two feet, the pri the hand will In- heard plainly in the t< phot It tins is tin- case, tin- dii turbance created in tin- mind should tain)) make it felt in the audion, for thinking being first of a chemical na- ture, tin inly must give ri capacity effects. Hut let us assume thai live thinking does not give rise to ws electrical "i otherwise, then the mere chem- ical action (and resulting capacil should produce a disturbing influence upon the audion. These variations, it i -light, could then he amplified by the use of an audion or other amplifier, and the resul- tant effect he sent into an Eunthoven string inometer. The small mirror attached to the string of the galvanometer will send it- luminous pencil upon a light-sensitive p tape which moves at a certain rate of speed in front of the mirror. The result will be a wavy Become a line traced upon the paper tape in the well- known manner. The paper tape traveling Doctor of Chiropractic ein will pass thru its fixing tank, and from Advanced Science of Spinal Adjustment there will emerge from the outside of the machine after it has past thru a small dry- Here is your opportunity to prepare yourself to enter the profession of ing chamber heated by electi ical coils. Chiropractic— the modern science of relieving ills and ailments through spinal adjustment. No matter where you live or what you are now doing, you can From this, it will he understood that a enter this uncrowded profession a profession of good incomes. Some of our man sitting in front of his Thought Re- — graduates report they are making $3,000 to $5,000 and more a year. teach corder will he able to actually see on a tape We mail or in class. his recorded thoughts, the same as the tele- you by grapher working on a trans-Atlantic cable watches his tape and its wavy line produced 22 Complete Charts by the Syphon recorder, emerging from the latter. Of course, it will he necesary for in Drugless Healing everyone to learn the "thought alphabet" FREE just as the stenographer today must learn As an extra inducement to quickly secure new students we will give you, the various characters, or as the child is absolutely free, our 72-page book and 8 Anatomical Charts, beautifully litho- taught how to read and write, and as the graphed in lifelike colors, that regularly sell for $15, cable operator must learn how to read the also complete set of colored Nerve, Pain Area, Con- Our Lessons Teach Ton Syphon recorder "alphabet." All this, how- cussion and other Charts that regularly sell for $16.50. howtomakeSpinal Adjust- miss this liberal offer. ments for speedy relief of ever, is simple, and is only an educational Don't Get these free charts by all means. See how you qualify as a Doctor Headache Neuralgia feature once the apparatus has been in- may Indigestion Neuritis vented. of Chiropractic and what splendid opportunities this Lumbago Catarrh profession offers you for gaining an independence. Epilepsy Fevers The objection naturally comes to the mind Never before has the demand been so great for Doctors Pleurisy Jaundice immediately that even if we have a ma- Constipation Dyspepsia of Chiropractic. To meet this demand, we must have Rheumatism Paralysis chine to record the thoughts, all we will get more students immediately. Write today. Asthma Etc.. Etc. on the tape will be a jumble of contused thoughts, and we might get a lot of thin.:- Learn At Home To Be a on the tape that were not meant for record- ing or registering at all. Such criticism, of course, is beyond controversy for the simple Mail write a letter by hand CHIROPRACTOR reason that when you or on the typewriter, you have also at first No special talent or advanced education necessary. If you have common school education, the is institu- a lot of confused thoughts, but you do way open to you. This tion trains you either by mail or in class. Learn in your own (ouponToday not record such thoughts even by hand or home in yourspare moments to be a Doctor of Chiropractic. It by machine. It often happens after you offers you a profession of dignity and prestige. Let us prove M how YOU can make a good income. difference You benefit by mentioning the "Electrical Experimenter" u-hen writing to adiertiscrs. . 66 ELECTRICAL EXPERIMENTER May. 1919 free romouj,§. mm l\g©sd this ferti^rK&kte Qlter? N\j(jM^Jj V \ OFFER No. 1 :=^ - ____^ Wireless Course l £j^^^^= =; = Course most comprehensive Wireless | ^^^vlwW \*^Y ^^Bll5§§§^^&= - Trie pages, ll- l printed- Contains 160 350 | (Cll?M \^^*^ /•• ,L„„ — =-,-1-^ ever book 634"xl0". Very - l lustrations. Size of \W!*W 'J ^^ ;', -,/gT gfafglBliBBSKfliffSffg | :? fine flexible cloth cover - ii!lrl) *r\^^^*^- ^f*^W M mSu ^EnffS&^^sStKI - >#/ I ^^^ v£ *2F3 VgiMlMi FREE with a year's subscription. Add 5c {or postage m ' ^vY~^Jy," .^35 f^^^^B^^B^^Sl^n^Si^S ^^w/J^~3 iiiiiitiM'iiini i Ill 'HI' ""- .llllllllllllllllllllllllllll 1 1UHIIUIU HII OFFER No. 2 ^Li^i :^^^^^^^I^^^^S I Experimental Electricity Course A t^^SlS^^^^^^^P^^^v 1 ; contains < /S O^. '^^Sv 1 This masterpiece 160 | V^« ^ -^5^^^^^^^^^^^^ , '9*'' /* Size I ^/^S^^l^^p^' I pages, 400 illustrations. ,H/ ^^Sis_ = " of book 5 x9 - Printed on ex " S ~^^*foi ^fft\ fy) '^^W = *De tra tbin a er - so D°°k can v ty)t TS» /^j *^^^s. i p P i ! pocket. Hand- ''o ^V/? slipped into °'" ^£\s^9^-*^^ 5 a some n exible cloth cover. ^J^/ft, <2j, *^\ OFFER No. 3 ^- /-*- Ce> £f, '^Yv. - How to Make Wireless | W~%SS' %. ^ V^-^iX >* *'"V\ i Sending Apparatus ^<\*J*P'' \<> Ct, TV»Vj 'v\ By 20 Rod' Experts ' tySf /t'^YV = How to Make Wirelew I \ *»% Receiving Apparatus *%, tf HjQ^Sgfe \ s' I J - praise these e 'IIMK'VSi'^^r^t^^^^^^ /^^ cannot books to hi h Each book ° s 'y- • W^B^'^f^W^Mm = I / pages I contains and IWH^^^A^ ^\$^5\^/ \ 100 " jftn^L from 88 to 90 illu stra- ! ^'as, \y-. .. | tions. BOTH books | '/^y ^ \ I FREE with a year's sub- j | scription. Add 5c lot postage I 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 have only a limited supply of these fine books on hand; after they are gone we cannot reprint the books until con- ditions become normal again. Now is your chance. The publishers of this journal have earned an enviable reputation of giving more than 1 00 cents' worth for each dollar spent with them. Profit by this liberal opportunity NOW; it may never be made again. HERE'S THE OFFER ^^ Subscribe to the ELECTRICAL EXPERIMENTER for one year, at the regular subscrip- A\^B £&L SU^ tion price of $2.00 per year (Canada, foreign and N. Y. C. $2.50) and we will send you either books shown in one of the above offers. If you subscribe for two years, Gentlemen: ^ \ ^Cjjj WlS^ two offers will be given, etc. Please enter *<£• \ ^8SBg»t , c • • , , , , . i r i my subscnp- \y \ 'WjH Wl " you are a subscriber at present take advantage or this wonderful opportunity the tion to v:::::":::::::::::.v:."v::... 4> Name *if Address v You benefit by mentioning the "Electrical Experimenter" when writing to advertiser — May. 1919 ELECTRICAL EXPERIMENTER 87 in thru set water it m. Tlhe True Wireless An illuminating experiment is indicated By Nikola 1 20 in wlmli two grounded trans- the (Continued from ; mits rs arc shown, one » il md other with a small terminal Sup- former pose that the latter I the greatly from the intensity "i the Inn that it is charged to in til oi the two impulses because the electric i tential and let the frequency in both the mountains is raised, as I have explained circuits and therefore the currents in connection with my lightning proti antenna Your I Strengthen in the EXPERIMENTS! of Febri with the smaller capacity v. ill then times the energy of the other but the on the receiver will be in no wise propor- tionate. EYES! The same conclusions will be reached by transmitting and receiving circuits with Preserve Your Most Precious In each case wires buried underground. Possession tions carefull) investigated will be Transmitter found to be due to earth currents. Numer- Your light is your most precious gift. iit be cited which can Weak eyeslgbl moans weak power of ob- »•;. un- ih verified. So for example oscillo- servation, eye strain. and with of low frequency are ever so much told tnconYenience. Take no chancel more effective in the transmission which is your eyes— you cannot get aloriK without wit; a. Mj them Make them stroi day in- Fig. 17. Illustrating Influence of Obstacle In inconsistent the Path of Transmission as Evidence Against observations in 1W0 an - r it nn.g and -the simple. Mr Si effective eye educational exen i inwiiiiu acfadded. Eye Defects Remo'cd TO ALL you to your This remarkable new Course teaches how use ilhnm ..train at all distance* —how to do without AMATEURS glasses-—how to remedy cross eye* or squint eye* —how to the normal sight—how to restore perfect control to Fig. 18. Showing Effect of Two Hills as eye nertes and muscles. Further Proof Against the Hertz-wave Theory. We have received many thousands 3 Beneficial Results at Once 1 of communications from radio ama- No drugs, medicines or operations. The Course Includes a more effective, which could not be the case simple, yet thorou,.! -ystem of eye educational 1 teurs for the past few months asking in a transmission with Hertz radiations, us about the status of their radio sta- anient continue* daily <> "n like manner if two grounded circuits are I they will be allowed woman vritM 1 notice a great Improvement In n. | tions, and when learning to dm already im 1 to operate them again. prorlng." ail ill another HTltes, "Words cannot eipn gratitude fur these excellent books." (Names on re- offi- Inasmuch as there has been no QUSSt. ) 1 cial information as to the reopening Send No Money you this new "Strengthening Eyes" 1 of amateur stations, during the arnii- Let ill MDd Court* the on five days* approval. Th- -imple Utile I tice. we can only say that in all likcli- lessons winch will show you the way to strengthen and serve your sight the gift of the gods! Try tin . be allowed to — 1 hood, amateurs will not then return the Course if nol -,tn-tied and you win o« / operate until actual peace has been nothing. If. It '. 1 that the Course will / help yuur eyes wonderfully, send only* J5.00. y signed, fn his executive order of I Mail Coupon! / \pril the 6th, 1917, President Wilson If you value your eye;, if you steal - / closed all radio stations in the United and want to get rid of U»em. If j * Transmitter | ' \ weak or if rou vranl to Physical Transmitter approved in the Radio are or strained, | grounded Stalls by an act Insure freedom from eye troubles, mail r .separated Culture Pub. without 1912. coupon now / Qo from ground Law of August 13, "Strengthening the Ey«t." * -' n.nf lens break By—but mail coui-w. by spark gap J; J7„.u CV ' I 19 W. lNn si. Such a measure, according to law, now. as this offer may never appear again / New York City duration of the war, is only for the Ontlenieii : DL l /- u S •r '-> -r-*-r- -r-7~™ '~V~' Physical Culture / i there being at present no legislation Send me youi Publishing / 'sircuirtlu'tiini; t h a which prevents any station, amateur or | / Byes" whirl, l will re- Fig. 19. Comparing the Actions of Two Company from operating after peace - / turn In 5 days or Forms of Transmitter as Bearing Out the 1 otherwise, you $5 in payment for tho Fallacy of the Hertz-wave Theory. has actually been declared. Therefore, Dept. 5605 / 119 West / course. the minute newspapers announce that 40th Street / Name to day the effect is Address observed from day 1 peace between the United States and N. Y. C. / greatly with the damp- found to increase the Central Powers has been signed, ness of the ground, and for the same reason all amateur stations automatically re- 3 vert to their former status, and ama- Transmitter rrith small 1 teurs need not wait for permission to I terminal capaaty i operate their stations, once peace has = i been declared. Transmitter m'tfi large EDITOR. terminal capajcefy WANTED — Railway Mail Clerks 1 Age 18 to 35 WRINKLES, RECIPES & FORMULAS. $1100 to $2000 Year Franklin Institute Dept. E101 (Continued from page 42) Common Educa- Rochester. N. Y. If carbon dioxid is to be generated, fill tion Sufficient tube A with marble chips and tube B with Sure pay. Sirs: Send me. without charge. £ (II sample Railway Mall Clerk dilute hydrochloric acid. Life Job. ^f Examination Questions: (21 Pull unnec- schedule showing places of all It is evident that the parts of the penera- examinations; essary. £ I tor can be easily cleaned and new chemicals (31 list of other goTcrnment jobs now open, and (41 free book describing them. put in. The completed apparatus is shown Hertz-wave Theory Fig. 20. Disproving the in Fig. 3. by Two Transmitters, One of Great and the Other of Small Energy. tributed by S. WEISINGER, JR. mentioning the "Electrical Experimenter" when Writing tj mdverheers. — 88 ELECTRICAL EXPERIMENTER May, 1919 FOR EXPERIMENTERS ONLY !! quantity have in the past held many extraordinary sales, but we believe We have bought a large block of these goods and have a large are WEthat t lie present one eclipses all by the wonderful values we Immediate shipment can be made on all of the of every item on hand. offer on this page are all standard offering. The goods which we goods in practically any quantity within reason. Shipment within telephone Every piece we are offering is equipment that for apparatus. twenty-four hours will be made if you use the coupon at the bottom of discontinued by the telephone companies. one reason or another was this page. This coupon saves you several days and your order will then If of the pieces which we offer herewith, from you wanted to buy any be considered a rush order. We guarantee every piece to be as repre- the manufacturers, the price would at least be ten times what we are sented, and we will refund the money if goods are not exactly as asking for it. You can readily ascertain this for yourself by looking claimed by us. over our wonderful prices. telephone work, and you will even find it sensitive two 5 REPEATING COIL (Transformer). This is NO. I TELEPHONE RELAY, 1500 ohms—has NO coil and is used by all enough for short, distance wireless work. sliver-contact springs and is very sensitive, fan be a standard small repeating 4 different wmduigs and No. 7 Bell Telephone Receiver— sliip- works on NO. 10 MICROPHONE AND BRACKET. An A-l NO. 12 POLARIZED RINGER with Bells. The polarized and has a powerful magnet. It if run at sensitive microphone of the carbon grain type. Has resistance of the two coils is 1250 ohms each. The (56.6 cvcles and any magneto will operate it instrument. hard rubber mouthpiece and enamel steel bracket, the armature is perfectly adjustable. Bell will work on a certain speed. A very finely built Re- con- instrument being 10 inches long. This microphone, in any magneto. We also furnish blue print with ringer sistance of each coil being 200 ohms. Can be polarized relay can be made verted into a polarized relay by substituting a very Ci nnection with our No. 7 or 8 Receiver and No. 16 showing how a first class furnished. Ringer Box, will constitute a complete telephone out- by anyone using only a few pieces of metal and fine leaf spring inside the heavy one A interesting instrument with which to experiment. fit, good to speak 50 miles or more, at a remarkably screws. most Polarized Ringer with Bells— ! order. It will ; 231 Fulton Street leave us within : ELECTRO IMPORTING CO., NEW YORK I ADDRESS i 24 Hours. •SAAAAAAAAA/V I STATE.... You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. May, 1919 ELECTRICAL EXPERIMENTER 89 My Iirwentifcns Typewriter Sensation mtinutd from / engineers of a defect involved in the trans- hkc that governing the conversion ol me- formation by the new method, namely, the chanical enern We ma) FREE TRIAL Use as You Pay Only $4.00 a month until the low total price of $53.15 is paid, and the machine is yours. This is absolutely the most gener- ous typewriter offer ever made. Do not rent a machine when you can pay $4.00 a month and own one. Think of it—Buying a $100.00 ma- chine for $53.15. Cash price, $50.35. Never before has anything like this been attempted. Standard Visible No. 10 Smith Premier Perfect marhlnne. BUndard size, full 84 character one motion keyboard Th< tine at writing completely rlalbli baa the tabulator, the two-color ribbon., irftti automatic reverse, the. back ipacer, ball bearing type bars, ball bearing carriage ac- tion, in fad even late style feature and ting convenience. Comes to you with everything complete; tools, cover, oper- ating book and instructions, ribbon, practice paper— nothing extra to buy. You cannot imagine the perfection of this beautiful re- constructed typewriter until you have seen it l have sold eeveral thousand <>f these latest style Model No. 10 machines at this baicain price and every one of these thou- sands of satisfied customers bad this beauti- ful, strictly up to date machine on five days' tree trial before deciding to buy it. I wilt send It to you F. 0. B. Chicago for tire days' tree trial. It will sell itself, hut if you are not satisfied that this is the greatest type- writer you ever saw, you can return It at ray expense. You won't want to return It after you try it —you cannot equal this wonderful Mechanical Analog of Tes/o Oscillation Transformer•(&*<») value anywhere. You Take No Risk—Put in This revolutionary Improvement was exhibited and explained by Tesla tor the first time In his lecture before the American Institute of Electrical Engineers May 20, 1891. It has made possible to generate automatically damped or undamped Your Order Now oscillations of any desired frequency and. what Is equally Important, of perfectly constant period. It has been Instru- mental in many great achievements and Its use has become universal. The underlying principle may be briefly stated as WhSD the typewriter arrive deposit with the ex- fit. the machine for five follows: A source of electricity Is made to charge a condenser and when the difference of potential at the terminals of press a^ont 15 and take trial. If that It Is the the latter has reached a predetermined value, an air-gap Is bridged, permitting the accumulated energy to be discharged days' you are convinced through a circuit under resonant conditions, this resulting In a long scries of Isochronous Impulses. These are either Bwrlter you ever uw, keep it and send mc 14.00 until our bargain price or $33.15 Is directly used or converted to any desired volume or pressure by means of a second circuit Inductively linked with the first a month If it. return it to the and tuned to the same. The above diagram Is taken from Tesla's lecture before the Franklin Institute and National paid. you don't want $1». 15 return Electric Light Association In 1893 and shows more elaborate arrangements of circuits, now quite familiar, for the con- express agent, receive your and me. I will pay the return version of ordinary direct or alternating currents Into high frequency oscillations by this general method. In the the machine to banes. This machine la suaranl mechanical apparatus Illustrated, an attempt Is made to convey an Idea of the electrical operations as closely as practi- if (or 11 It li standard. cable. The reciprocating and centrifugal pumps, respectively, represent an alternating and a direct current generator. as roo raid (ISO. 00 Orer hundred thousand people own and use these The water takes the place of the electric fluid. The cylinder with Its plastically restrained piston represents the one and think tin in the hot ever manu- condenser. The Inertia of the moving parts corresponds to the self-Induction of the electric circuit and the wide ports ten around the cylinder, through which the fluid can escape, perform the function of the air-gap. The operation of this factured. supply at this price Is very limited, the price apparatus will now be readily understood. Suppose first that the water Is admitted to the cylinder from the centrifugal The will probably be raised when my next advertise- pump, this corresponding to the action of a continuous current generator. As the fluid Is forced Into the cylinder, the ment appears, so don't delay. Fill In the coupon piston moves upward until the ports are uncovered, when a great quantity of the fluid rushes out, suddenly reducing the today mail to me the typewriter will be shipped pressure so that the force of the compressed spring asserts Itself and sends the piston down, closing the ports, whereupon — — promptly. There Is. do red tape l -niploy no these operations are repeated In as rapid succession as It may be desired. Each time the system, comprising the piston. solicitors—DO collector!—no chattel mortgage. It rod, weights and adjustable spring, receives a blow, It quivers at Its own rate which Is determined bv the Inertia of the Is simply understood that I retain title to the moving parts and the pliability of the spring exactly as in the electrical system the period of the circuit Is determined machine until the full $53.15 Is paid. You cannot by the self-induction and capacity. Under the best conditions the natural period of the elastic system will be the same lose. It is the greatest typewriter opportui as that of the primarily Impressed oscillations, and then the energy of the movement will be greatest. If. Instead of the will ever bare. Do not send me one cent. Get the centrifugal, the reciprocating pump Is employed, the operation Is the same In principle except that the periodic Impulses coupon In the malls today—sure. of the pump Impose certain limitations. The best results are again obtained when synchronism Is maintained between the natural oscillations of the system. these and Harry A. Smith, 758, 218 N. Wells Si., Chicago gation showed that no matter what medium carry it to the lower level along any devious H. A. SMITH. 758. 218 N. Wells St.. Chicago. III. is employed, be it air, hydrogen, mercury path, it is immaterial insofar as the amount Ship me a No. 10 Smith Premier V O It Chicago, a.t described in this advertisement. I will pay you vapor, oil or a stream of electrons, the of work is concerned. Fortunately how- the $41'i0 balance of the special 153.19 DOKtUsM $4.0" month. The title efficiency is the same. It is a law very much ever, this drawback is not fatal as by proper price, at the rate of per to remain In you until fully paid for. It 1$ under- Conrocrs proportioning of the resonant circuits an stood that I have five dan in which to examine and try the typewriter if I choose not to keep it ==™-» Primary efficiency /vr cent is attainable. Since at of oS I will carefully repack it tod f. fcj c of) press agent. give the my early announcement of the invention it It Is understood that you standard guarantee for one year. has come into universal use and wrought a Name . revolution in many departments. Hut a still preater future awaits it. When in 1900 I obtained powerful discharges of 100 feet and Hashed a current around the globt. I was reminded of the first tiny spark I ob- Condenser served in my Grand Street laboratory and Fig. 3 Scheme of Circuit Connections In ACCOUNTANCY — was thrilled by sensations akin to those I The Highest Paid Profession taught thoroughly Tesla's Oscillation Transformer Shown In in a few months of Fdt when I discovered the rotating mag- home study by new system Fig. 1. The Secondary Circuit Which Slips CDEC RAnK International Accountants Society Into the Primary Is Omitted. netic field. mfct WVWn 0cpt 39KM26S. Mioh. *»». rMt*& You benefit by mentioning the "Etectrieat Experimenter' uhen writing to advertisers. : 90 ELECTRICAL EXPERIMENTER May, 1919 I TRANSMITTER BUTTON r of a which may be an ordinary pony telephone receiver (single Fig. 1 shows how the music Transmitting means pole), which must be wound to five ohms or otherwise the re- violin can be transmitted by Violin The sults will not be satisfactory. By winding the receiver spool of the Skinderviken button. full and evenly with No. 26 enamel wire, you will get about button may be attached to any part Music the de- five ohms. The battery between the standard receiver and of the violin and if it is not S ohm receiver must be sired to drill a hole into ascertained by experi- the violin which may ment, usually from four be valuable, there are six volts and some- numerous places where to times as high as ten the button can be at- volts are required. It tached by means of a should be noted that - VMMnli Fig. I small nut, or if this is f W T the Skinderviken but- *°""> Re- 2 sealing wax into which the thread ! desired a small lump of not easily burn out and can stand about one ampere will do nice- ton does not is quickly prest before it cools, part of the button continuously. The more battery current put on, the louder transmitted from one room to another. ly. Music can thus be the voice. The important part now to consider is the trans- mitter horn, which must be made of white bristol board, the ! how to transmit piano Transmitting Fig. 2 shows same as used on visiting cards. Buy it at any stationery store. music at a distance. The button is The horn may be from 14 to 30 inches long, and the opening ! Piano attached to the front sounding board at the small end should be about /il inch. It can be attached into the sealing wax to the receiver cap. On the loud Music by drilling a very fine hole by means of ordinary receiver diafram will do. altho one a trifle panel, or should this not be desired, talker, the works better. No magnet is used in this receiver as the described under Fig. 1. heavier it can be attached by sealing wax as pull on the diafram is electro-magnetic as well as concealed as desired. The wire can, of course, be the transmission of the voice. This device talks An interesting stunt can be performed by inter- very loud. the receiver posing a battery into the line, and Fig. 4 shows how you shown in our diagram can then be the ordinary How to Make can make a telephone ex- house telephone receiver. Piano music can then a Telephone tension to an existing tele- be transmitted to your friend who may be hun- phone system. Suppose you Extension telephone subscriber dreds of miles distant, and the music will be ab- are a and you wish to have another extra phone some- solutely clear. The same stunt can also be per- where in the building for someone else to listen in formed, of course, with the violin as shown in all you need is a Skinderviken button mounted Fig. 1. on a cigar box as shown. When the receiver is taken off the hook, it is placed on top of the cigar i Fig. 3 shows how an ordinary A Loud box directly over the transmitter button and from telephone receiver can be made there the usual line runs thru a battery to the re- Talker into a loud talker. Very often ceiver. The distant party can then hear what is said. If it is desired to have him reply also, it is desired to have a telephone Fig 3 being it .for to talk conversation come in so loud that every one in in that case will be necessary him into a Skinderviken transmitter and an extra line with a tele- the room can hear it clearly. Our illustration shows how this phone receiver near the house phone. The party who makes i can be done. The telephone receiver connected to the incoming the connection would then naturally have to take the receiver line is attached to the top of the base board as shown. The only and place it over the mouthpiece so that the party at the other alterations will be as follows: The cap is unscrewed and its end of the wire could hear what is said. This arrangement is Skinderviken button as hole is enlarged somewhat to take the not shown in the diagram, but it is self-evident. shown. A thin iron nut is then attached, necessary on account " ^8" ^ shows an interesting instrument of the pull exerted upon it by the telephone receiver. If the "J-Jowler and _ called "Howler". It is used in connection j is single pole type, the arrangement as telephone receiver a 1 elegrapn with telegraph practice instruments. It receiver is used, a shown in diagram is O. K. If a double pole Practice Set gives a loud clear musical tone every time small iron plate instead of the nut must be used, as otherwise the telegraph key is depresst. From two the pulling effect will not be so good, altho still appreciable. to three dry cells are used. The construction is somewhat simi- lar as explained in the illustration is self-explanatory. It is important that the nut does not touch the telephone pole No. 4 and The underlying idea is that the single pole telephone receiver piece, as otherwise the transmission will not take place. It will works the Skinderviken transmitter which in turn again oper- be necessary to underlay the diafram with a few paper washers ates the telephone receiver, giving rise to a clear note ; the same in order to raise it sufficiently. After the Skinderviken button as if you take an ordinary telephone receiver of your house has been attached, it is necessary to enclose it in a sort of phone and place it over the transmitter mouthpiece, only you in illustration. This box may be a sound-proof box as shown will find that the tone of the device described above is much bet- turned wooden box, but ter and clearer. This in- CMI0601W1 ' tM^ffi™™.) an old telephone receiv- strument probably con- JD**CtLL5 »A5l nou will nicely. stitutes one of the best er shell do aT\kr\e^ fi? r It should be attached and simplest learner's outfits. It of course, by means of sealing wax can, also be used as a radio as shown, making it en- test buzzer, simply by sound-proof. The tirely connecting one of the two transmitter wires transmitter wires to the are then connected to a detector. It works very loud talking receiver well indeed. Fi s- 5 SKINDERVIKEN BUTTON COMPLETE $1.00 PREPAID ni • 1 .i if .,, crcrn 2118-2136 N.Clark St., Chicago, III. Til r Address us as steco, Skinderviken Telephone tquipment to. or New YoA City N Y You benefit bv mentioning the "Electrical Experimenter" when writing to advertisers. May, 1919 ELECTRICAL EXPERIMENTER 91 TRANSMITTER BUTTON Mi trii a.1 experiment- ' )NG da )i : ' can easily make :i highly 4? 100 ers die button h Bensitive detectophone by vv lation. It i- not inn ommoo usingusini a Slunderviki a I ransmittei unsolii ited letters like Button to '"11" t the sound waves. vi these: 1 n i < 1 transmitter button today and You can build your own outfit without buying I wish to inform you that it works great at nsive equipment. Think of the fun the best I have ever seen or heard of for the would have with such an instrument! price. I will icrtainly recommend it to my It's very >ini| il;-. too, and inexpensive. friends. I wish to thank you for your good You can install an outfit in your servke." ' "I nave been u-in". one of your transmit- home and hear the conversation ter buttons, and it has proved to be worth all house. " held over the You can more than its value in my experimenting nect up different rooms of a hotel. Transmitter Button i some time ago, and they are just O. K. for ex- (>ur outfit was used by secret st i perimentary." "I have been using operatives during the War. It one of your transmitter bull' stage. IS being used on the So experimental work and it certainly much for its commercial adapta- lives up to all you say for it and tions! You can procure appa- BARGAINS then some." Mr. H. Gernsback, editor of this ratus of the same type. These prices are very low magazine, who is t In* One of the main it. Mil of electrical ex- All equipment is GUARANTEED. The appa- ln the writer's opinion, ob- advantages of ratus is the same as sold by us to large i ;i 1 1 1 .-.I ln.il telephone companies. 110 volt telephone by a c Skinder v i k e n our generators. J fitter Button Is Transmitter But- lbs. 3 bar $1.75 Weight 6'/2 probably most efficient ton lies in its ul- 4 bar 2.2S 8 lbs. device "f Its kind on 2.75 10 lbs. market to sensitiveness. 5 bar today, due tra- 1 lb. Its Ringers 80 ohm. . . .35 simplicity and " 1 lb. other cutatandlni You can place it 1000 ohm. . . .75 " ures. Should have a great future." Silk cords, 6 ft. 3 cond. .20 3 oi. in any position " Figures ti. 7 .iri.i .Mm.- very " " 6 ft. 4 cond. .20 3 oz. " ting experiments. Thai of repro- you like. It is the greatest in- «• • 3 ft. 2 cond. .10 1 oi. iluriri^' music at ,i point far removed complete with vention in micro-phones and has Transmitters from t ho phonograph is very popular with Steco transmitter button $1.50 12 oz. experimenters. The Sklndsrvtken Ti won recommendations from men Induction coils 35 6 oz. milter Button is mounted In a very small holy in the under side of the sound arm. of high standing in the scientific (Note : Tills hole will not injure the qual- ttte world. It is being used all over ity of music, i When tlie phonograph Is being played, the sounds produced are trans- can it most anywhere. the world. You mount formed by tlie skinderviken Transmitter Button In figures 3, 4 and 5 are shown some un- into a varying electrical current The receiver, usual and practical methods. Card board which is located in another room, reproduces the music at that i Stove pipes, Stiff calendars and hun- boxes, Figures 7 and 8 illustrate the methods of dreds of other places will surest themselves transmitting sound by means of tin* vibrations to you. The buttons cannot be seen by any dy whil, sneaking. Speech will he repro- by the receiver just the same as if the one in the room as they are so small and experimenter had spoken into a transmitter. In light. Only a small brass nut is exposed to tlise experiments the Skinderviken Transmitter the view, Button is mounted on a small iron disc The same circuit connections apply to all experiments, regardless Full directions for connecting up the button for use as a of how the transmitter button is moo detectophone are given in booklet No, 4 which is sent with The Skinderviken Transmitter Button operates on one or two dry each button. Figures 1 and 2 of this advertisement, two of rells. It often happens that two celts produce too much current and the sounds are the many illustrations deafening. We mi e 11 d either one in booklet Xo. 4, show fresli cell or two worn out the circuit connections We have the utmost of the detectophone. faith in our transmitter The only instruments button. We guarantee lurv service or we to complete a needed will refuni the purchase detectophone outfit, in price. ! 1 ong and send In a dollar bill addition to a Skinder- old— BIGHT Now I Sou can't viken Transmitter But- it' you're not satis- ton are a receiver, bat- tied, you receive your dol- k. Isn't that fair? Pig. 1 rig a and, if desired, an Transmitter Button mounted mi Dia- tery, Send a 8c stamp for a Transmitter Button mounted the same phram. Simplest circuit. induction coil. copy of Booklet No. 4. but with Induction Coil USE THIS COUPON City. Y. Use Pencil) F. 5-19 2134 North Clark St.. Chicago. Illinois, or New York N. STECO. Bnclose sufficient postage for mailing enter order for Gentlemen : — Please an re aid Skinderviken transmitter buttons »'•«<> P » Ship to. f os. 110 volt generators bars ® "J Ringers ohms ™{ r! ^ Wt lbs. Cords conductor ft | « wt os. Induction coils f Wt. ^bs. Transmitters with T. Button •| 50 Send Booklet N . I [ 1 Telegraph Keys •"» j-l-i^j j ^^^^^^^^^^-*-mrmm. "" Si | un.ii wiling la advertisers )ju benefit by mentioning the "Electrical Experimenter" — — — 92 ELECTRICAL EXPERIMENTER May, 1919 "Sr Opportunity Ad-lets will to read and investigate the offerings will find many remarkable opportunities and real bargains in these columns. It pay ypu VOD be seeking, whether supplies I made every month by reliable firms, dealers and amateurs from al over the country No matter what you may most attractive specials ot the automobile accessories, the opportunity to make money, or anything else, you will find listed here the best and " accepted Name and address Advertisements in this section seven cents a word for each insertion No advertisement for less than 50c an accredited advertising agency. must be included at the above rate. Cash should accompany all classified advertisements unless placed by advertisements not accepted, Ad- Ten per cent discount for 6 issues, 20 per cent discount for 12 issues. Objectionable or misleading vertisements for' the June issue must reach us not later than April 22. The Circulation of the Experimenter is over 100,000 and climbing every month l EXPERIMENTER PUBLISHING CO., INC., 233 Fulton Street, New York. N. V. >^liu:"" J mri f nn i iii nnTiJiimgiP 1 juuuiimiiuiiuiJUJiUiiniiuJPi 1 m * umiunimmuiimmimriarmiJi m imj uijnnji [lli>l[lllll!IIIIINNIIIIIIllllllllllllll|lll||||||||!l|li|!l|||||||||||||||llllllllllll[llll Illlllllltllll! IIIIIIIIINIIINI mi — Automobile Accessories. Tricks, Puzzles and Games. Exchange Ads. Continued. Sell— Variety of articles, apparatus, etc. Write c Card Tricks— Sensational Escapes Liquid Silk Automobile Polish, finish lasts as Magi wants. Send stamped envelope. Vernon Palen, Jokes Novelties. Everything in the amusement long as new car, or money back. Sample 25c. — Sparta, Wisconsin. line. Large illustrated catalog of a thousand prepaid. Liquid Silk Mfg. Co., Delanson, N. Y. "Multi-Audi-Fone", tricks free. Write today. Largest amusement brand new, $15. Try this with your Ford power Mechanical Products greatly in- {goods manufacturers in the world. Heaney Magic Audion or any detector. C. Francis, Box 1504, Providence, R. I. crease ability Ford Cars, Sedans, Trucks, Trac- Co., Desk 200, Berlin. Wisconsin. — tors, Racers, "4 Speed Forward Auxiliary Trans- Leading Magical Magazine! All magicians like Wanted Quick! Volumes 1, 2, and 3 "Elec- mission"; trical Experimenter" either bound separate Double Power, High, Low; Reverse; it! You will, too! Why? The value is there. or Powerful Motor Brake descending hills; "Abso- any odd copies purchased. Good prices offered. Sample, 10c; three months, 25c. ; year, $1.00. lute Neutral.*' Easy winter cranking. "Full- Eagle Magician, Dept. E, Minneapolis, Minn. Write for particulars and price to Box 70, Care power" "16-Valve Cylinder Head," 20^-64% Electrical Ex perimenter. Black Art Hindoo Experiments, 1919 Edition, Power increase, government test. Other Ford For Sale Receiving set 25c. Invisible Ink. Free Trick. Catalogue each — $10.85; consists of 15 Power Devices coming. Opportunity agent, and 7 inch double slider coupler, cat -whisker, dealer, Victor- order. Linhorst Magic N Shop, St. Louis. owner. Send for trial plan K. detector, 14 point loading coil 17 and 3 inch. Have illustrations. Cata- Ford Trans. Mfrs., 246-248 W. 54th, New York. 1000 Stage Tricks with 500 other wireless things. Send for list quick. logue 10c; small catalogue free. Hornmann Fords run miles George Faunce, 5 Green Street, Millville, X. J. 34 per gallon with our 1919 Magic Co., S ta. 6, 170 Eighth Avenue, New York. carburetors. cheapest gasoline or half Cheap Cyclopedia Applied Electricity. Stamps, Use Novelties, — kerosere. Start easy any weather. Increased Tricks, Puzzles, Jokes, Toys, Games, Coins, junk. Howorth, University, Miss. Doll and Cane Racks, Plays, Wigs, Stage Sup- power. Styles for all motors. Runs slow high Exchange plies, Escapes and Illusions. Large 1917 catalog —Cycle-car for Smith Motor Wheel gear. Attach yourself. Big profits for agents. or bicycle engine or free. Magical Co., Dept. Oshkosh, $50. Send stamp for par- Money back guarantee, 30 days trial. Air-Fric- Oakes 549, Wis. ticulars. Carl Mayo, Orleans, Mass. tion Carburetor Co., 270 Madison St., Dayton, Wanted— Ohio. 100 Kinds Wire and Steel Puzzles. Catalog and Whimshurst Static Machine. All let- ters answered. leader, 10c; postpaid. Western Puzzle Works, J. Picucci, 670 57th St., Brook- iiniiipmiiiniiijiiinniiii™^ lyn, N. Y. St. Paul, Minn. Aeronautics. For Sale—Shaw Motor attachment, $20. Harold Lambert. Haver straw, N. Y. Flies 2,000 Feet—Manhattan Racer, 26" wing 77 5. Spencer Street, Typewriter—Like new— For sale or exchange. spread, made finest materials, strictly a speed Aurora, III. John Galbreath, Rogers, Ohio. and distance aeroplane for amateurs. Great for Feb. 6, 1919. § For Sale—25 Watt Dynamo parts, $10. 2 K.W. spring and summer outdoor sport. Complete Editor E. E. y 1 Transformer Coil, $5. Electro Oscillation Trans- materials, knockdown, carved propellers, assem- Dear Sir . The small ad I had in the former, $5. Loose Coupler, $2. Navy Receiving bling and flying instructions, Postpaid in H $3.50 3 February issue is surely bunging some great Transformer, $15. Blitzen Variable Condenser, U. S. Blueprint only, 35c. Postpaid. Blueprint results, about six letters each day from all S3. Murdock Variable Condenser, Variable Bleriot racer, guaranteed 600 foot flver, 35c. I $3. over the United States and Canada. Condenser, $2. Ground Switch, $1.50. 2000 ohm Postpaid. Hec Aeroplane Co., 6 West 48th Street, H I would like to know the price of one phones, $2.50. Home Medical Apparatus, New York City, N. Y. $3.50. |e insertion of the one-inch ad I am in- Post Card Projector, $3.50. Bell Ringing Trans- nniinnintmiiiiniiniininNiinniimM^ =. closing also cost of six insertions. former, $1.50. $30 Mecanno, $20. All in good H Please answer quickly. order. First draft or money order takes them. Motorcycles. Yours truly, Burrows Rogers, Cainsville, Mo. Sell or Exchange—Ford Gray & Davis Starting Motorcycles from $25 up—New and second - = Howell Rang. and Lighting system; Shaw bicycle motor at- hand. Easy terms, large list to choose from, all tachment. Want Dynamo 2 K.W. or larger, makes. Send 4c. stamp for Bulletin "A." Peer- y 24. to 60 volts direct current, or screw less Motorcycle Co., Watertown, Mass. cutting Exchange Ads. lathe 8" swing or larger. Frank Pantel, Mus- i ij i rm r n i j m i n i if KTBppirmfiTTnTiTnfTini 1 mmiTTnn 1 mnniTS J tTjn p jjj f cat UJ1 IFini JIIPTIII1J For Sale— Single barrel shotgun, no v. Port- ine^Iowa^^ Telegraphy. able electric heater, Hawkins' Guides, Zeno For Sale—Blueprints of motor windings, see chewing gum vending machine, and other arti- ad under Blueprints, etc., this issue. Charles cles. For description and prices, send three - L. Chittenden, 811 West 181 St., Kansas Telegraphy (both Morse and wireless) and City, Mo . cent stamp. Earl Brown, 514 Virginia Ave., Railway Accounting taught thoroughly and I have wireless apparatus and other things for Martinsburg, W. Va. sale. for quickly. Big salaries now paid. Great oppor- Write list now. George Sharp, 73. picture for Everett tunities. Oldest and Largest School—est. 45 Wanted—Small motion machine Ave., Providence. R . I. home, price about $10. Donald Porter, Frazee, years. Catalog free. Dodges Institute, 7th St., Sale—Send stamp for list of wireless Minnesota. instru- Valparaiso, Ind. ments, all. bargains. Geo. Sprouls, 5624 Pale- Sell—Motorcycle engine; telescope; chemicals; thorpe St., Philadelphia, imiiiiiinmrrinniiiiiDirinuinniinninQTiiinnTiTinT EmTnTminniTirrmrnninnnTiTnniiiiniBD ununmninai Pa. electric motor. Shank, 521 Jefferson St., Dayton, Sell—New $50 Phonograph, $25. C. Gillespie, 72 Stamps and Coins. Ohio. Woodward, Buffalo, N. Y. For Sale— 1 K.W. Packard transformer, round Sell—Motorcycle engine, $10.00; Magneto, $3.00; 100 Different Stamps 10c, 200, 25c Michaels, detector and amplifier bulbs. Will buy old type Spark coils, $1.50; Generator, $1.25; Motor, 75c. 5600 Prairie. Chicago. General Electric Induction Fan Motor. Harry Harley-Davidson Motorcycle, $30.00. Ruben Hil- Free—Packet Valuable Stamps to Applicants Weber, 1113 Walnut St., Dover, Ohio. born, Brown City, Michigan. Approval. Benj. Forbes, 160 Devilliers, Rifle telescope sight and Kraig rifle 50% Wanted— Wanted— 14 K.W. transformer, Packard or Pittsburgh, Pa. or carbine. A. L. Chamberlm, Box 132, Daven- Thorderson. Clyde Stream, 2537 Elm wood. 300 Different Stamps, 35c; 100 different U. S. port, Iowa. Kansas City, Mo. Electricity, 21c. C. Reitter, Box 1054, Detroit, Mich. Bargains—Cyclopedia Applied $15.00; Boys! Big mechanical Engineering Set. Con- Popular Science Library, $10.00; Excellent condi- 78 Different Stamps to approval applicants. tains three motors. All for $75.00, cost a lot tion. First money order takes same prepaid. T. Enclose 5c. Harland Burgett, 419 Spring St., more. Send cash in registered letter. Russell Raleigh, North Carolina. Lima, Ohio. H. Blacknall, Box 107, McOuilkin, Millport, Col. Co., Ohio. Sale Regenerative Receiver, Storage Battery, For Sale—Twenty large American cents, all — Pocket Tester for electricians, trouble-shooters other apparatus. Write for description. Thomp- different dates, for only $1.55- Old coins bought and maintenance men. _ For use in place of son, 36 John St.. Worcester. Mass. up to 1916. Catalogue, 10c. Savage, 436 Melville lamps on 90 to 500 volt lines for locating shorts, St., Rochester, N. Y. For Sale—Twin Motorcycle, or engine, New grounds, opens and blown fuses. Size 2^" x 5", Sayville Rotary spark gap, $7.00. Two Portable neat leather case with leads for testing. $1.50 Stamps—61 all different free. Postage, 3c in spark coils, wireless and elec- Falls Electric Shop, Cuyahoga Falls, Mention paper. Quaker Stamp Co., Toledo, Ohio. Wireless Sets, postpaid. trical instruments. H. Gary, 600 Main St., Ohio. Stamps—Send 25c. for our collection. Some Aurora, 111. Sell—White Cross Vibrator. Almost new, half fine ones. Facastenhz, 425 LaGrave, Grand Wanted—Smith motor wheels. Johnston, 9 price. Write Wm. Waldrip, Attico, Ind. Rapids, Mich. Rutherford, Binghamton, N. Y. Swop. Whole Laboratory! Electrical' California Gold, Quarter size, 27c; Half-dollar Sale— Wanted—Small Graflex camera. A. Hofman, Bargains. Write for list. All answered. Chas. size, 53c; Dollar size, $1.10; Large cent, 1820, and P. Q. Box 809, City Hall Sta., N. Y. Derrick, Grampian, Pa. catalogue, 10c. Norman Shultz, Kings City, Mo. For Sale—Wireless instruments. Vincent Na- Cleaner with 500 Finely Mixed United States or Foreign For Sale—$60.00 Retina Vacuum talish, 68 West 56th St.. New York City. $25.00. P. Crawford, 13 Ten Broeck Stajnps, 12c. Philatelic Star, Madison, N. Y. attachments, Head Set—New Brandes distance phone—3,000 St., Albany, N. Y. CTfnronnMMMiroiM list Ohm, $13.50, sell $8.00. Send stamp, large Sell—5 H.P. 2 cylinder gasoline engine, $46. Old Money Wanted. Receiving Electrical apparatus. Dare, 94 Clinton Will exchange for screw cutting lathe. Herbert Ave., Brooklyn, N. Y. Sicklesteel, 802 12th St., Detroit, Mich. '" " ,, |, |, l :" . ' ' five dials clock driven : : .. .:.. urn We Buy and Sell Old Coins. $2 to $500 each For Sale—Omni graph lIIlllllI^I^^l^Inmllllll[ll^lllltl^^lll'J! polarized relay paid. Keep All Old Money; you may have valu- wireless code, quenched gap, 5 Scenery for Hire. less able coins. Send 10c. for New Illustrated Coin ohms, stepup transformer. Will accept no Scenery for all Plays. Amelia Value Book, Guaranteed prices. Get than $25 for outfit. Pastime Theatre, Union Collapsible 4x6. Pennsylvania. posted. Clarke Coin Co., Box no, Le Roy, N. Y. Hill, NT. Grain. Philadelphia, You benefit by mentioning the •'Electrical Experimenter" when writing to advertisers. p — . d May. 1919 ELECTRICAL EXPERIMENTER 93 . __ ... . - Agents H tinted Pntjajti Opportunism / ->r \h 11 fc-*»y. : Pbuul Work r mi Make Die-Castings. Razor Bladet dollars and Proposition, i.e. Byrd \ Blair, It \ Eric , Pa. South loth, i 1 ' !.. Bi( St ':....:;! - 1 Why 11 Perfumes and Toilet Goods ior _ t utlery Co., jpg H t ..n. Ohio. 1 .Mi the • Help W anted. Insyde 1 yres, n lie hres, Memphis, •1 blOW SO Tenn. Mcn-Womm, , unrdl- Demand atel> Manufacture 1 1 electrical specialties. -. free. 1 1 ' r pi- 5-4, sales wanted \\ • < » North Phila., ClllC I t 1 [ Wril Pa., IV 1 > Box 5861. mi- mical Novelty foi old and Young. Bar- I>epl I V. Earn Money at Home. "The Reliable Plan" tells ho W-ntrd V. r leers to start Collec- New Jersey. tion I < c Rullct i , Conn. year! tin and refer b \ .. lory- Mechanical Toy Soldier Klran-Ritr window at- to" free. it. Salutes, turns head, Whirlwind srllcr. Great K. Bureau, Dept. 20, 65 Mayna r Shipments prepaid. with linger, etc., as set. Well made, Special Dollars ' — i 1,- Saved I k3 Offf IpOttdcnCC nicely ,, cur-'T !:• ^it-\cr Produt L> Polk St., Sam, etc. tional Electrically operated. 1 t every . 111. Bureau. Victor, X. half minute ..r oft iel and will salute Y. $1* Daily refinishing ili.nn; soldier and pay a to other if de- Be a Detective. Good income. Excellent op- '>iles by new method, withoul capital or sired. Repn portunities to travel irs irer. v. I Ttt p.irli ultr s and proofs. Write town. Writ- for prices. The John M. Bi Amerii a School of Criminology, Dept. E. Gunroctal Co.. Ave. Decatur, 111. D, Box 324. Chattanooga. Tenn. troit, Mich. Miracle Motor-Gas amazes motorists, jc. worth Dollars Yearly in Your Back Yard. No gin- Make Die-castings. Sketch, Sample, Book- line. Eliminates carbon, yn^'r scng, mushl Investigate. let and Proposition, 12c. Byrd & Blair, Box 2-7 I. 1 'Shin 500 p Particulars free, .\fctz, 313 East 80, New York. Erie. Pa, Sample* tr< '. - _-;-- : — -, Enter .it I — j Butler, SecV, Dept. 70. Toledo, Ohio. Earn $3,000 to $6,000 onal fees making and fitting a ' History of the World War," by Francis A. Hooks. toot specialty, op' where with all the brother of t ieni r.il .March. Authentic, - - trade \ ily learned by any- Books for Real Live People. J tr- TT"" complete 750 pages— illustrated—official photO- — one at home in a few weeks at small expense; Sheridan. 417 E. 151st St.. New York. credit given. no fun no goods to buy; Dear Reader— If Occult, fit. Vietoi New-Thought an job hunting, soliciting or agency. Address entitic books to Company. 641* Manhattan Bldg., Chicago, appeal you, send for my catalog. Stephenson Laboratory, 18 Back Bay, Boston, it*s free. Illinois. I have books on i Mass. Concentration, Spiritualism, Install Farm Lighting Plant*. Big Profits. Build Up an Income in Oil -Others are doing ship. Will, Mind, Hypnotism. Mesmerism, Char- Plana at once. Wolkce Co., it Why not you ? Today is the opportunity. Ri sdingr, Healing, ' Louisville. Kv cess. Join our easy monthly payment plan now — it Salesmanship, Mi 1 hanii , Entertainment, etc. may mean hundreds in profits. Write A. W. Martens, j-40. Burlington, Iowa. Cameras, Supplies—Photo Developing. formation. National Oil Drilling Co., Dcpt. K, 24 Money-Making Formulas, Houston, T 25c. $15 course in candy making—6 complete lessons for 50c. Both Kodakers: How would you like to get a 9 x 11 books 60c. Alton Studio. Alton. I >w a enlargement of your best negatives free? Drop $30.00 a week evenings. I made it with a small us a card right now asking about it. Films mail order business; continued my regular Where to Buy Right; How to Advertise. 2— developed at 10c. per roll, prints 3c. 4c. and 5c. job daytime. Free Booklet tells how, 2 cents expense 25c Box 115, San Francisco, Calif. post ige Albert W. Scott. Cohoes. N. Y. eacl utced. Ford's Foto Invisible Inks—30 formulas, 15c. Horton P. Ellensburg. Studio. Washington Patents for sale. To buy or sell patents ad- Jones, Perry. la. Mail Us ISc with any size Film for develop- dress Patent Ncws-H, Washington, D. C, only "Nature Book" facts every married and en- ment and 6 velvet prints. Or send 6 negatives inventors' newspaper published. gage 1 person should know, 35c. Central Cora- any size and 15c. for 6 prints. 8 x io"rnounted pany, 509 Ninth Avenue. New York. Big enlargements 35c. Prompt, perfect service. Roa- Get our Agency Plans at once. Wolkee Co., World-Romic System, Masterkey to All Lm- noke Photo Finishing *So., 255 Bell Ave., Roanoke, _ guages. Six Textbooks. $1-44. French Chart. Va. Louisville, Ky. 37c; Spanish, »C| Aviation Dictionary. $1.50. French- Frane's Brownatone 2Sc. Tones --50 pictures "Quick-Action Advertising— How it is Building English Aviation Dictionary, 61c. Languages, beautiful brown; easy ts washing prints. Frane, Business for the Progressive Advertisers of 143 West 47th. New York. 111. America"; little story of results, told by Eureka. A To Get Better Pictures: Read the Amateur the advertisers themselves not the publisher. Special Trial Offer. Your next Kodak him de- — Photographers* Weekly; illustrated; weekly You will be interested in reading this little veloped, 5c. Prints 2c. each. Moscr & Son, 1919 prize competitions; print criticisms; many booklet, which we have prepared for prospective T ames Ave.. Cincinnati. O. unique features; $1.50 per year; three months' advertisers, a copy of which will be gladly Finishing at the trial subscription 25c. Abel Publishing Com- Clean, Neat, Perfect Kodak mailed to you upon request. It tells you how pany. 401 Caxton Bldg.. Cleveland. Ohio. 't prices. Work returned the same day re- to talk business with 1,000.000 intelligent, inter- of 1. Send film for sample print and copy ested and responsive Americans every month Old E. E. Back Numbers: We have some valu- log on Developing, Printing. Enlarging and men who know what they want and who have able old E. E. back numbers on hand as follows: of Craft Maga- Hand Coloring, also copy Photo the money to buy it. Write for particulars and 1915—J-'in., March, April, May, June, July. Aug., zine, which will help you make better pictures. rates today. Douglas Wakefield Coutlee, 225 Sept., Oct.. Nov.. Dec, price each 35c. 1916—Jan.. Photo Craft Co.. Box 60, Ann Arbor, Mich. West 30th Street, New York. Feb., March, May, June. Sept.. Dec, price each 35c. Make real mystic photos without camera or 1917—Jan., April. May. Aug . Nov., Dec, Are you in search a plates by using Star Photo Papers. No experi- of a formula to produce each 35c 1918—Jan., Mar., May. 35c; igiS—June. certain preparation? If so, perhaps we can help ence necessary. Complete out tit for making 15 July, Aug., Sept.. Oct., Nov., Dec, each 20c. you. are ever on the alert and closely fol- pictures, 25c. Abrams Co., 1305 Peoria "St., We 1919—Jan., Feb., Mar.. Apr., aoc We can fill or- Chicago. lowing the development of the industrial arts in der* at once upon receipt of your remittance, and all its branches. Our standard price for each if you have not these numbers already, now is six or eight exposure film up to Post Any formula or process issued is Thirty -five cents. your chance to get them, as they probably will be Card size developed and printed, 10c, or enlarge- Let us hear from you._ Industrial Methods snapped up verv quickly. Experimenter Pub- 10. your fa\orite negative, 20c. Special ment, 8 x Bureau. 320 Fifth Ave.. Xcw York City lishing Co., 233 Fulton St.. New York City. Introductory offer to show high quality work. 1, : ; " ~- -.; 1 I!' 1 Photo Co., Dcpt. 12, Cincinnati. Sta. A. Iceless Refrigerators. Particulars for stamp. Bacliman. Box 57. Fullerton. Penn. Health. Hurry: Issue. Plans and specifica- Chemicals. Our First Tobacco or Snuff Habit Cured 1 for building National Advertising Weather if Chemicals and Laboratory Apparatus for tions cured. Remedv sent on trial. Supcrba Co., Service. Sales talk picture of finished machine, SA, Baltimore, analysis and experimenting. April list 5c. Md. etc. Profit $150.00 for manufacturer. Protected Frane. Eureka. 111. Pyorrhea— H. E. Kelty D. D. S., at D.. pyor- territory. Descriptive literature, terms and pic- rhea specialist for 15 years, has developed a suc- Chemicals or Chemical apparatus — We have ture 25 cents. None free. National Sales Co., cessful home treatment for pyorrhea. Purifying, what you need. Our lists are without end. Box 421, Lima. Ohio. State your requirements. We also make up ex- healing, preventative. Full "month's treatment perimental sets of any value. The particulars Start a profitable business manufacturing and booklet $1.00. Circular free.^ Dr. H. E. of our standard sets will be furnished upon re- "Puffed Crisp". Delicious confection. Whirl- Kelty. 106 Gladwin Ave.. Leonia. X. J. quest. Zeigler Experimental Laboratory, Roches* wind money-maker. Machine, Instructions com- Cigarette, pipe or chewing habit conqu< ter, X. Y. plete $6.«;o. Samples 10c. Bestevcr Products Co., Nature's method. Guaranteed. Write for free St.. 2426-E5 Polk Chicago. brochure. Edw. J. Woods, TA-300, Station F. X e w York, Stammering, Want to make $30 a week in spare time ? 'HMIfffflMIMBsWWWWIM^ Particulars. 20c. Walker. Box 465. Dayton, Ohio. Sta-nmering at home. permanently eradicated Formulas. Cure positively guaranteed.^ Particulars free. Opportunity— I have a comprehensive, electrical ::irc Training Keene. N". H. System, \ -a liable for development, that should 500 Formulas. Re silvering Mirrors, Renewing ~~_y- - -' ~ ' " ' t~i: '-;;: r-\-r* j ,_] iMim revolutionize a certain industry. Interesting Dry Batteries, Luminous Paint. Mechanics' Soap, research is here afforded experimenters and in- 35c. Catalogue ac Ideal, 5501 -E North Robey, For Advertisers. ventors in something new, useful and worth- Chicago. 111. while for amateur and experienced electrical Unheard-of Trial Offer! Inch displav or 30- 20.000 Formulas. $1.00 postpaid. List 4c. Oscar classified advertisement ten weeks, $1.0.3. people. Postpaid three dollars. Roy Y. Hughes, word C. Han son, Me ntor. Minn. Record Advertiser. Box 2E. Houston. Va. Electrician. Mitchell. South Dakota. Consult Us when in need of definite and re- "Quick-Action Advertising-How it is Building Big possibilities in new profession. Easy to liable data concerning any trade formula or Business for the Progressive Advertisers 01 learn in comparatively short time. Field of industrial process. « >-.ir standard price for each % America'*; A little story of results told by the practice unlimited. Many so engaged earning formula or process Thirty-five cents. advertisers themselves—not the publisher. You $2,500.00 to $10.000. 00 Exceptional oppor- Write us now. Industrial Methods Bureau, 320 will be interested in reading this little booklet tunities for women. Write to Howard College, Fifth Ave.. New York City, N. Y. which we have prepared for prospective adver- :_- S Ashland Blvd., Chicago, Illinois. —,—„ tisers, a copy of which will be gladly mailed to you tipon request. It tells you how to talk rVesflS Correspondents. business with 1,000,000 intelligent, interest Collections. writing news responsive Americans every month—men who Earn $25 Weekly, spare time, for Expcrien know what they want and who have the money How to Collect Accounts; also Exposure of I, magazines^ tails frc Louis. Mo. to buy it. Write for particulars and rates today. Membership and Contract Collection Agencies. Douglas Wakefield Coutlee, 225 West 39th St.. Booklet 25c Smith Mercantile Agency, Jeffer- New York. son, Ohio. Continued on pzge 94 You benefit by mentioning the "Electrical Experimenter" when writing to aJi crttscrs. A : 1 94 ELECTRICAL EXPERIMENTER May, 1919 'WiiiiiiiiiiiiiiiiiiiiiiniiiiiiiiiiiiiiiiiiiiiiiiiiiiiiHiiniiiiiiiuiiiiiiiiiiiiiiii: iiiiiiiiiDinioiNiiiiiiiiiiiuiiiiniiiniiiuirnuiiiiNiiiiniiiiirrfoninnriimiiiniim imii iiiiiiiiiiiiiiiiniiiiiiiiiiiiii iiiiniiliinii iiiiiiimiiiiiiiiiiiiiiniiiiiiiiiniiuiiuiiiiiuiiiiiiiii'. Supplies Appliances. For Inventors. Patents for Sale. Electrical & Your Transformers. Costs Inventors. Protect your Idea before exposing Automobile Direction Indicator, Electrically Make Own a few operated. Patented. Manufacturing cost cents to make. Will ring bells, buzzers, etc. No it. Advice Free. Inventor's Patent Service, Just Royalty batteries required. Guaranteed, instructions, Park Row Building, New York City. low. Ability to Finance means money. 25c. or contract. Investigate. L. A. & A. A. Own- Abrams Co., 1305 Peoria St., Chicago. 600 Mechanical Movements, also illustrations bey, 1210 East 5th St., Chattanooga, Tenn. Install Farm Lighting Plants. Big Profits. and explanations of 50 perpetual motions. My : : Get our Agency Plans at once. Co., 1 Wolkee i 1 i:vllili:ui.IV . : : ! 1: :,mli til 1 1 [tn 1 1 1 imni;i t;.':i 11: n;: book, Inventors' Universal Educator, 4th edition, UHUIMG l!lin;';it;i; 1 . i : 1^ ;r Louisville, Ky. procure and sell a patent for your tells how to Miscellaneous. new invention. Government and other costs. Repairing and rebuilding Galvanometers, Volt- meters, Covers the matter from A to Z. 140 pages ele- Ammeters on any electrical instruments. . Gasoline Steam Engines. gantly bound. Contains noted Court decisions Wanted—Small and V. W. Bradbury. Winnsboro. La. Cash paid for 1 to 4 cylinder light weight on Patent cases. Mechanical Movements greatly Propellers for Air Propulsion. Practice Motors. to 10 H.P. Johnston, West End, and assist inventors—suggest new ideas that might !4 Professional blades Pittsburgh. Pa. made to order. Crawford prove of great aid in perfecting inventions. Tells Motor and Aeroplane Manufacturing Co., Pitts- how to select an attorney. Has valuable informa- Blacksmith, Listen! Prepare for big wages in burgh, Pa.; New Orleans, La. regarding Patent Sharks, Selling Agents and Navy and Arsenal with Toy's Modern Methods tion Inventors' and Manufacturers'. Experimental Brokers. Price $1. Postage free, Ired G. Diet- doing hard jobs easy. Forging and making solid work, models, tools, instruments, light ma- erich. 603 Ouray Building, Washington, D. C. welds, hardening and tempering to a standard, with colored tempering charts. All for one dol- chinery. Over twenty years' specialized experi- Inventions Commercialized. Cash or royalty. ence working from samples, blue prints, rough lar. Sample free. W. M. Toy. Sidney. Ohio. Adam Fisher Mfg. Co., 205 St. Louis. Mo. sketches, explanations. Customers' supervision snow from sidewalks, Inventors join National Institute of Inventors, Snow Plow. Removes in machine shop permitted. Manufacturers' and lower. Thoroughly tested. World Building, New York City; membership etc. Easy to raise or Inventors' Electric Co., 29D Gold St., New York. Can also be used as toy. A. H. Tallyn. Benson, 111. society 1.900 strong; will help protect, develop, Get the proper apparatus tor your experiments. Class. finance and market your invention. Absolutely Be a Top Notcher—Get into the ioo'/r Coils, Electro-magneto. Solenoids, Resistances, no charge. Write for booklet. Be Prosperous, Powerful, Happy. Our system Inductances and Condensers, designed and con- It can show YOU. imuuuiiiiLtLituiuiiiinuiiiiiLumiuiiiuuiiuiiuiuumuiULiiiuiuiirmiiiBUiniiiiiiiiiiimiiiMiiiiuiiiiiniiiiUD has shown thousands HOW. structed to your order. E. Fast, 5840 W. Erie Proved. true-to-life Person- J. No guesswork. A St., Chicago, 111. Patent Attorneys. ality Sketch and first lesson on Happier Living Problems and advice in Radio, Mathematics, for 10c. and birthdate. Thomson-Heywood Co., Patents Procured—Trade Marks Registered— Electricity, Chemistry, etc., answered by experts De pt. 350, Chronicle Bldg., San Francisco. Cal. comprehensive, experienced, prompt service fot for $1.00 and up. Paragon Technical Bureau, 329 Black breeding foxes. the protection and development of your ideas. For Sale—Choice Silver East Fifth Street, New York City. furnished without R eid Bros., Bothwell, Ont., Canada. Preliminary advice gladly 10 Security Ford Locks, new, at $3.50 each, of and form for Doubles your charge. Booklet information Julian's Liquid Fishing Lure. regular $5.00 locks; 100 ampere combination Ford request. Richard B. Dollar. Julian, disclosing idea free on catch. Trial bottle. One George Locks for switch at $2.00 each, new, regular Bldg., Washington, D. C, or Building. Boston. Mass. Owen, 130 Owen Albany price $3.50; one Palor Cut 6" Electric Fan, new, 2278-T Woolworth Bldg., New York. 5" Special—Cardboard tubing, impregnated. at $4.25; one telephone, new, 50c; one Premo M. F. Miller, Ouray Building, Washington, diameter. 20c per foot. Postage extra. Maier, Camera, No. 1—3*4 x 4>4 Second-Hand at $6.00. D. C. Patent Attorney, Mechanical and Elec- 335 East 93d St., New York. Electrical, Optical and Technical Supplies. H. C. results. trical Expert. Best quality of work and Plastography Instruction with model or mould, Hancock, Bogota. N. J. charges. Advice free. r Moderate $2.00. Success awaits you. P. B. Spahr, \ ork, Look! Save Money! Heavy aluminum 10 x \z Millions spent annually for ideas! Hundreds Penn. sheets, fifty cents; inch strip, 12c. ft. Heavy Patent yours and profit! Write strip, 18c. ft.; inch, 10c. ft. now wanted! Fancy Mice 30 Varieties; send stamp for list, l'/t inch brass H free tell how to protect your- — Robert Duffield, Detroit, Mich. today for books— or 50c for book giving full information on Postpaid. ideas wanted, how we help self, how to invent, varieties, housing, breeding, etc. Holman's 25c. in coin will- answer that question on Stor- Industries, Inc., 212 you sell, etc. American Mousery. Dedham. Mass. age Batteries. Henry G. Oakes, 81 Triangle St., Patent Dept., Washington, D. C. composed to words. Bauer Bros, (for- Buffalo, X. Y. Trade-marks Registered. Music Inventions Patented. nerly of Sousa's Band). Oshkosh, Wis. Look! Penlites exact representation of foun- Labels, Prints and Publications Copyrighted, " flashlight, Marvelous! Send for our time-saving multipli- tain pens, 65c; 6y2 tubular $1.05. reasonable fees; correspondence solicited; de- batteries Products of any amounts readily Postage 5c. extra on either. Extra tailed information free; booklets. Jaynes & cation table. pocket size card. Price 10 sold. J. McLardie. 424 Edgewater. Dayton, Ohio. Jaynes, 702 Kellogg, Washington. D. C. calculated. Handy cents (coin) by mail. Remittance with orders. Will buy and sell anything electrical, chemical Invention. Personal Service. Protect Your Tabluated Information Card Co., 2040 Chestnut or mechanical. Send for list and send in list sketch for honest advice. J. Reaney Kelly, Send St.. Philadelphia, Pa. and pric es. Box 255, North Bennington. Vermont. 732 C, Woodward Bldg., Washington, D. C. "Opportunity Adlets" bring quick results. Our 24 Dry Cells Recharged for 4c. Instructions, Your Inventions. Save attorney's Patent Own 100.000 circulation, net. Other firms are making 10c. Walker, Box 465, Dayton, Ohio. applications; furnish full in- fees; we prepare so can you. For proof address Classified satisfaction. Free informa- money— imiiimiiiiiimiiiMiiiiiiiniiim'Jiiiiim structions and give Department, Electrical Experimenter, 233 Fulton Carl Larsen Co., Park Row Building, New tion. St., New York City, Blue Prints. York City. iiffliiiiiiiininiuininiiiiniiiiiiimtmiraiiiiniiiiiiiraiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiillB James N. Lyles—Patents, trade-marks, copy- iniiiiiiiiniiiiiiiiniiiiiii Blue Prints of Motor windings. 108 A.C. con- nections, 132 D.C. armature windings, complete rights. 734-D Eighth St., N. W., Washington, Motors, Engines and Dynamos. 240 diagrams $5.00 cash. Send 25c. for 12 samples D. C. or write for particulars. Charles L. Chittenden, in monthly install- Motors Patents— My fee payable Small Motors and Generators: 1000 New 811 West 18th Street. Kansas City. Mo. ments. Send sketch for advice. Booklet free. and Generators from Bankruptcy Stock, \i H. P. Blue Prints: % H.P. Gas Engine, 30c; K H.P. Frank Fuller, Washington, D. C. A. C, $18.50 each; J4 H. P., $30.00. Battery Steam Engine, 50c; Vs H.P. Boiler and Engine, McLachlen, Atty. at Law, Patents, Charging Sets—Robbins & Myers new outfits, all John M. 70c; all 3 for $1.00. Circulars on Castings and Copyrights, 410 McLachlen Bldg., sizes, $30.00 each and up. Charging, Lighting Trade Marks, each Engines for stamp. Universal Gas Motor Co., Washington. D. C. and Moving Picture Arc Generators, $10.00 of current. Im- 364 Monadnock, Chicago. Engineer, Mechan- and up. Motors for all phases Patent Attorney, Electrical OilllQniiaiiniJDiiiniiiiiiimuuDnnijniitiimiiui'iiiiiMsiDiiinruuuinuuiiuaiiiumniiiiiiuiiib:!: mediate delivery. Less than Y2 regular prices. Expert; Thorough Personal Service. Frank ical Write for late bulletin. Johnston, West End, 21 Park Row, New York. Instruction. Ledermann, Pittsburgh. Penna. cnTiiiiiiiiiiiiifliiiiiiiiiiiuiiiiiiiiitaiiuiinniiiiiiiiiiiiniiiinTiiniijiJiiiniiiiuanatniuiiiiuiiiiiiiiiiiiiiiiiiiniinu For Sale—Motors, all sizes. Write your wants. Typewriting learned easily and quickly at Printing. We have them. E. Billstone. Jamestown. N. Y. home by Modern Fingering Gymnastic Method. Marine, row- New discovery by long experienced typewriting Quality Printed Envelopes, size 6J4, 50c. Gas Engines for every purpose. 100 Engines from instructor makes expert typists. Demand in- Postpaid. Name cards same price. K. \\ lese, boat, stationary and motorcycle. year. Write United creased salary. Complete course, twelve lessons, Atlantic. Iowa. $10 up. Guaranteed one Motor Repair & Supply Co., .305-309 Broadway, five dollars. Guaranteed. Enroll today. School Style Visiting Cards 5"C ; 100 100 Engraved New York. of Modern Method Typewriting. Warren, Ohio. Emblem Cards 70c. H. Gregory, Warwick, N. Y. , 500 Watt Motors, Modern, Efficient, cost me Over 100 Brunches thoroughly taught by mail. iiiiiiiiiiiiiiiiimiiniiiiniiiiiiiiiiiiniiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiNiiiiiiiiiiiiiiiiiiiiiiiiiiiirairaiiiiiiiiiii $n. Investigate! Duplicate! Clark, Barnes For "Free_ Tuition", apply Carnegie College, Wireless. Road, Newton, Mass. Rogers, Ohio. 1 50-H.P. Gasoline Engine, 4 cylinders, alumi- ulMli/^i'UiiiniiiiiiiiiiiiiiliiiiiiiiliiiiiiiiiiiiM :':'' i:mminiii:i!:. 1 ,. Complete receiving sets $8.50, $9.50 and up. num, cost $1,500. Will take $450. Geo. B. Song Poems Wanted. Instruments, parts, minerals. Circular for Bo utelle, 324 N. Eutaw St.. Baltimore, Md. stamp. Inquiries invited. Jenkins, 923 Purchase Dynamo, brand new, under Write the Words for a Song. We write music Street. New Bedford. Mass. 10 Volt, 20 Ampere and guarantee publisher's acceptance. Submit Call Saturday evening, 354 Convent Switch Points. Binding Posts, Switch levers, half price. poems on war, love, or any subject. Chester Music Ave., New York. and small parts, send 2c for catalogue describing Co., 918 So. Michigan Ave., Room 265, Chicago. iiiiiirii«eiuwwiiDiwuiiiJiiMi]i™ these and other goods. A. W. Bowman & Co., 23 You Write the Words for a Song—Submit Cambridge. Mass. Church St.. (Harvard Square). Novelties. poems on war, love, or any subject. Chester Music Before you build that new set get our free write music, guarantee copyright and assist in circular on switches and contact points. Hard Latest Fad, $1.00. Blanket flag sofa pillow. securing publisher. Metropolitan Studios, Room rubber knobs used. Eureka Secondary Co., 6939 Covered with 24 flags, 8 shield of arms, satine 113, Morton Bldg., Chicago, 111. Fletcher, 1711 S. Oregon Ave., S. May St., Chicago, 111. lined. Fletcher & iiiiiiiiiiiniiiiiiiiiniiiniiiniiiiiiiiiiiiiMiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiitiiiii: n Louis. Mo. Agents write for particulars. Radio Apparatus of Quality—Manufactured to St. Phonographs. your own specifications. Radio Engineering Snappy girl pictures. You will like them and Compa ny. Baltimore. Md. want more; 20 for 25c. Write today. Smith's Build Your Phonograph. "Perfection" high- Elizabeth, Chicago, 111. Bargains— H" Wireless Coils complete, guar- Novelty, (Dept. 5) 6735 quality spring and electric Motors, Tone Arms, i innnrnnnn rannnTin i mni ra nmuininn saving. anteed. 90c, except postage. Also Wireless imiiiimniniriininmiininnniTmtmijTimraiinnitnnijTnmnnii Reproducers. Wonderful results. Big Coils without vibrators, 45c, except postage. A. New catalog and building instructions mailed For the Hair. Indiana Phonograph Supply Co., Dubs, 1534 Pitkin Ave., Brooklyn. N. Y. for ten cents. In- Indianapolis, Indiana. Our Universal Radio Receiving, Detector, and I was Bald. Obtained hair growth by an Transmitting apparatus. The best that science dian's ointment containing genuine bear oil and Build Your Own Phonographs and manufacture instructions. Parts, and skill can manufacture. If interested write rare plant juices. Many others have good hair- them for profit. Drawing complete, sent free for catalogue. Universal Radio Mfg. Corpora- growing results. Will send box, postpaid, with Price List, Blue Prints, etc., 10c. Brittain, 150 E. 32nd St., upon request. Write today. Associated Phono- t ion. Elmira, N. Y. recipe, John Hart graph Co., Dept. E-t, Cincinnati, Ohio. Amateurs! Drop us a postal and receive in- BA-ioo. New York. teresting information that is of vital importance •iitiiiiiiiiiimiiiniirniiiiiiiiffliiffli QUMMlMI'iaim^ American to vou and future amateur radio. Personal. Letter Specialists. Institute of Radio Engineering. Omaha. Nebr. Letters That Land Orders and Money Orders- Gold Catwhisker is best for mineral detectors. Are you self-conscious—embarrassed in com- troubles written for $4.00; three for $10.00. Guaranteed. Hard drawn 18 Kt. Gold Wire 26 B. & S. 3% pany—lacking in self-control? These Criterion Service, Dept. 3, West New York, New inches, 50c. Sterling silver. 15c. Geo. Schuler, overcome. C. E. Veritas, 1400 Broadway, New Jersey. Jr., 126 W. 46th St., New York City. York City. N. Y 5*om benefit by mentioning the "Electrical Experimenter" when writing to advertisers. - 1 M ay. 1919 ELECTRICAL EXPERIMENTER 95 DAYI Bova. you can hava Bto.laa al four o«n home »lth Ihla I.I..I modal I D*g*'* **H *" ORE ATE ST TO Y SENSATION OF THE "TL fl Roku" n. I FI6HTJN8 DRMONAUOHT MOVING PICTURE MACHINE HSJHLjtss ""aS* tjT SENSATIONALLY REALISTIC 1 1 Meaeurea i aa tk« Uri»r michmn Vera- tuilr ma 3> but Mai ' ej '« Inchea ie*n, llrf* la i .M (iood Vwi* . >"<• - ii. , ., .. MULTIPLYING BILLIARD BALLS cooo luck rinc .sarir' Johoson Smith & Co^ Dtp!. £ 7. 3224 N. UalOed Si-, oiiaga end a> w Tha Baat Taat of Ita Kln« »*I«M Ill ifUii PraatUal frr*w Trim Your Own Hair With th« Eh scbanc* afm«in,i SlLa T»a)'a»tl*e. of.,( th* ti(\. um»r*l* I io 10, and [»int|„ni.iii m_ __ in aa *t~»i *d i**i tn* letlei |i i arTlla i roil. to r.i , Tha lli'f'f" ii poai.I n while Utility Safety Hair Gutter • a all**! ,,, * ruller snores the rati a riara and (nrrea Iha aapar f-i - Cuts His Hslr Any hat. •» "•< ">• !""• »•• *" " "."' dlaUDKa Length, laiut •!<(>'•- Earnlioaairilar In aatr . *> lid lull printed Dactad Ikiui thsrl or lt« •aaalafaaa. TSlra tamelaM. Si.Ou aant b. c teas— SsaaS JahawM S;aUh & Co-, Dept E 1, 3224 N. Hakled Si^ Chicago Cstt First Tima Ussd. fi-araill. a.jO.ri lr-m a.^>„ klxd <-l apaam a«d rat «-i..lh*r trail i. tha raault Tha (rat r.i. th.r. ba re- Price Wonderful X-Ray Tube «'"*o. 'h« balli dl.aapvariftaj una attar anuihar tl.at ,- Only SSo'tr.'S" SQUIRT I naiee rarnalni hi...., inlareetine erteh Ibal can C'iMB pa*ar hair I*e cea . _ rformad by lolloaHra; iha-'dir aetJ.... "»s«an" tba a^iarxui ewict. 2s cinti papar at MaLF eaicr, alb OaaLV ~ig Ca^WnL RINC f'sreaiD, — atlTH a CO. cciirjtij. shiih johhsom a co. /-a ,', l, E LaaretyMstv "« berkae at ;f:-"*4.:„*«.v; ... -->a- fourth the tint* bafor* ,. ar " "* roaiaiala u( ha'dauma- THE "LITTLE GIANT" TYPEWRITER n ralrwr. The ladies can cut lha child JJ a LOADED CIGARETTES ,: can b* B sad aa an ordinarj raj. r la taaaaaJ • .'«" • r ' ai'*->- ' a/, ind 'he A#f<*a«, tea rubOtr Sa'l, a- ar- a.. Uh A First Cla.a temptea and nack. Sfacpanad U J ri-d ar. iha real («• al raadr ifaV N^ffffA raaajed that iba Una. la VSafL f°r maianl us* and wnl la ffgV »•< «' >^"> Writing JafM V"* *— eon,l»rfiil •faaav ,),. A till •_, „,, u m tha pn>. Jchmon Smith A Co., o*.t t-i New 1 a 1-be of.fk and full printed Inatr-ir in* marnina. fricw coeaplata SUa hi mall poatpald wine tha r*aa-.'n Vamping 1 U>fu thalf ra SERPENT'S EGGS MYSTIC SKELETON I. aa>ar aitaaaet lha raal a bon^h of th*a* bitTa. aa Ut«r A fnlntadflsaira.'.faaVatateO limiird Each box containsi tains 12 Eggs. ** Hajraa.butthJok thai hara cao«ht It ona Mbperaonof nw»r.a i- n EaTaTS. d**^**7*Tc, Card Batvvaa tha I proapan.'H. Ii, Ot.Ur.- r. II baa UM otbar. UnahW a which are no larger than * ajvl aa bllta al tha pmp-rr lima and i»r(orm rarlooe p«* nt and moorrneDta whlla <.IT a ( rnuina bill or two from U . a (rmin of oats. " thar.>;.*.".oparat.* oiai be anj eel aaaae—a. aa# Haaa. *r am pW* *< oli'iM.' f'tha rt lit j When tanea fr«o JL Tha Otrara allwhaaa tiara la a n'rcin) paopla, will be fonrifj to b-a all that <-ai __ of b« aiamkiad br tba epaetatora. tt Vaba aat. Fft.alJt i aired >>•*, aj*atsaiai is enia mutch, however, UthatnawMl 10* When han ln^ . rtaaaof water and wh.o tft. »,.,r U p^^rad out Ih. rola haa *^aawS^riUl th acn^.^r.^^mdfollsrtnt.d In.Onclioft. fo, j-rformin. eacH iSiaf-a^'lh.7 .n.!f. JOHN5WN SMITH A CO.. OtPT £7. KM X MAL3TLD STREET CHICAGO S fODtat /*_ jfc in m Ml the Latest Surprising and Joke Novelties Potmend minutm eoBjorara. F«IC* COaieLlTH OwLT SO CliaTa" Tba flnaet repaJrer for Ironware. A rat*ware, JOHNSON SMITH & CO., Oept. E 7, 322* N. Halsled Street, CHICAGO Enaeaefwara.eU. Ceod for kallle* aota.aaaa, , W--,, gabtwTadba,. baklara. and aaarr k'»d of Ironware, alao fa* Sa: K^^iC_Ti it tie. copper, alaoUcMun. lea boiee. Iron papae, aa (a'baaa.'aataM at'iaarbt 10» _ eracka in atoraa, brvban china, poraalala. v Mawr ire** fa»" „ wcVarr. •roodaBwwre , n-*«ehle, ale. Will n"t chip, fry. TMK UFNDI.iI THE STRi INCEST SpnT STHI PQT Cwiiaa iat mi tha powder with w.ur. HARDENS UKE latOrf. t. Yew nao All a bie hole or a email tra^k bta^a^jatare Raplacaa chlppaw ewamel Anion* can do It: FAILURE UJ = aod auarUiu aaadar Tbxaw aiaae. IS Ceala. 2» cea* . ruuka. IP, a JDH.SOa SMIIM . OL 3224, JOHNSON SMITH A CO., Dept. 7, 3224 N.^als'ted^t7eet7c^CACO* Lloboaoo Smith A Co.. Dept. E 1 3224 N. HalateJ Pt.. Cblcaco mentioning the "Electrical Experimenter" when writing to advertisers. . 96 ELECTRICAL EXPERIMENTER May, 1919 TREAT YOURSELF Now made simple and perfectly safe With The Wonderful Health Restorer IOLETmy You Can Have Bodily Vigor, Success-Attain- ing Energy, Attractive, Healthful Beauty All at practically no cost—The great benefits of the Violet Ray treatments heretofore only procurable at big expense from physicians and beauty specialists are now available in your own home. Look over list of treatments below. Send for particulars. How Violet Ray Benefits Painless Electricity Electricity from your light socket is Science has modified electricity that transformed into health and beauty- the weakest may stand its force with- giving Violet Ray—powerfully effec- out fear or pain. Every tissue and tive, yet gentle, soothing, perfectly fibre if saturated, patient experiencing safe. Voltage is raised from ordinary only a sensation of relief, as if standing lighting current to thousands of volts, in a ray of sunshine. Violet Ray high giving tremendous penetrative force. frequency has no comparison with old, The irresistible, crude, electrical revitalizing pow- batteries and ers of Renullfe shocking current. Violet Ray are Every jar and carried at once to Renulife Violet Ray shock is removed. every nerve cell, The effects are fibre and part of HIGH FREQUENCY GENERATORS marvelously body. Blood is rapid. Relief can enriched and be given in one purified by a flood of oxygen, giving or more treatments. Often cures added vitality and strength. As- are accomplished in that time. It similation and digestion improved— is positive and certain in action. functions restored to normal—extra If you value your health, and want supply of fresh blood quickly brought to keep or restore your good looks to area treated, removing congestion and gain vitality, throw away medi- and supplying nourishment. While re- cine bottles—take this sensible, scien- lieving pains and aches, the manifest re- tific means. Violet Rays work with sults of disorders, it nature. Every COUPON FOR BOOK removes the deep- day's delay seated cause; com- Offered o Most Liberal makes relief more and Special Information bines the benefits of difficult. electricity, vibra- TRIAL PLAN Send for Book- RENULIFE ELECTRIC CO., tion, exercise, Learn the Wonderful Benefits 636 Marquette Bldg.. Detroit, Mich. stimulation and by Actual Use let, "Health via Please send without obligation, your book 'Health " explain- oxidation. Violet Ray." ing Violet Ray treatments with Renullfe Generators; also Rive full particulars as to its application for ailments checked below TREATS SUCCESSFULLY RENULIFE ELECTRIC CO., 636 Marquette Bldg., Detroit, Mich. . .Abscesses .Facial Neuralgia ..Obesity . .Anemia .Falling Hair ..Pain In Abdomen CANADIAN RENULIFE ELECTRIC CO. SALES REPRESENTATIVES . .Asthma . Female Com. and Chest 236 Netting Bldg.., Windsor, Ont. . Arteriosclerosis plaints Paralysis WANTED . .Baldness .Goitre ..Piles . .Blackheads .Gout .Pimples . .Brain Fag . Haemorrhoids . .Pyorrhea . .Bronchitis . Hay Fever . .Rheumatism . .Bunions .Infantile Paraly. . .Scars . Bruises sis ..Sciatica . Catarrh .Insomnia . Skin Diseases ..Colds .Lameness ..Sore Throat and ..Chilblains .Locomotor ft Ataxia Throat Diseases . . Dandruff .Lumbago . .Sprains ..Deafness and Ear .Nervous Affec- . .Toothache Diseases tions ..Weak Eyes ..Eczema .Neuralgia ..Wrinkles ..Enlarged Prostate .Neuritis ..Warts and Moles Name. .. j f , , ,,,„.,„ j) You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. — ! . — Electrical Man fonts These Books for your inspection I Hhi ! 10 Volumes 3500 Flexible Pages Covers 4700 Pictures Handy $1Per Pocket- 1 \olume Size J Volumes l Month Just what you need to know to succeed in ELECTRICITY EVERY electrician, every engineer, every mechanic should know READ THIS PARTIAL LIST OF CONTENTS about these wonderfully helpful instructive books, which give in No 1 plain words a complete working knowledge of electrical engi- —primary cell neering in all its phases. of dyuamos—arm.i commutation You run into some new electrical problem almost every day. The W— O Contains 348 ; i^u* £* information you need to help vou in your every day work is in principles—armature t calculations.—brake horsepower—-selection and installation of i and motors—galvanometers standard cells—eurretit nice measur- watt hour meters—operation of dynamos—operation of moto: No *\ Contains 123 illustrations. Distribu- i^vj* . o i:i j W i rt calculations side, outside and u -Iifiht- HAWKINS ning protection us, etc. « illustrations. Alternat- 1"]W rt A l, 379 ELECTRICAL GUIDES guide in one. written in plain day language no wasted words - every - - reference — . only what yon need to know chock lull of up-to-the-minute electrical knowledge. — ' nating — No fi The guides are a complete course in electrical engineering. They will help you In every detail of the day's electrical work. You can't ask an electrical question that lays—lightning Hawkins Guides can't answer. —synchronous condensers—indicai ng Contains 316 pag« ii\j.Mn 7 § ing current, Pocket-Size Flexible Covers management. Thi- to into i books are small enough slip your coat M Q igjes, 436 illustrations. Telegraph 1 rt Id black carers. 11U * *"* flexible — Imultaneous telegraphy and t> What Electrical Men Say You can earn- each volume with you until you have tometry, etc. mastered paces of actual information Wn Q Contains Eleo- Helped Him Make Good and 4,700 illustrations. Ones jrou see these books and nw ' ** trie raihv.v - light- put them into actual use you will never again want to be right for me I ing—trolley car operation m ippltcatioas— ^t> ihly the lk»r. without them. Try it at our expense. motion pictures- ga> ^Jr they have been of the - starters and lighting . . nii' in my I f\ Contains ng * 513 odent nf N v Elevators—crai. ' Ic Construction Department ol heating—electric welding ft> THEO. Companies. soldering and brazing — r Ohio's largest Electrical SEND NO MONEY industrial electro- AUDEL I would like to see every man turn a plating— electro-therapeutic set of Hawkins Guides. It will cost you nothing to receive these books—to look —X-rays, etc. &CO. them orer—ask them all the m can think of 72 Fifth Ave. Geo. Knecht. Columbus, Ohio. Also a complete 126-page rei pick ui. some reference Index Of the complete New York, N.Y. In the Naval Electrical Dept. Information that will ur earning ability. We ~aW will ship you the entln himes entirely FRKK, library. Tin's index has been "The Hawkins *** me On This is a slgi nfldence in Oie guides. Pnre planned to remKr easily ac help to me in the Naval r aW gold- does not objec COSSlble all vast Infor- examination Hawkins Department, which ti the W lays and if yon ]e that you can't get thortHU-i matlon contained In the Electrical Guides tsrles C. J C return them to us and owe us +4} • Iving Ship. Urooklyn. N. Y. nothing. 10 electrical guides. W $1 each). Ship at once, pre- ire over Superintendent keep them you nnlv have to pay 13,- ^^^ paid, the 10 numbers. If satis- 500 cross refer- $1.00 down an! The easy factory I agree to send you Jl "I am imw superintendent the of payment of $1.00 a month till pa You rind - within seven days and tu further Dunnville Hydro Electric Systems, hi ^ U| to wt the books. It will pay you what you want e^r and Hawkins Guides were a great many to 51 each month until paid. me in twilling down a re- know in stantly. AW^ W. K- Swartz. Dunnvllle, Ontario. THEO. AUDEL & CO. ^ Signature Wireless Operators Occupation. "I have work.'l wireless for ten 72 Fifth Ave. New York, N. Y. rears— hut I wish I had thi years ago. as they h.v Employed by. . . . great deal of trouble." H. Marshall. Steamer M ft H N r Residence Walkerrille. Out. L1END NO MONEY- USE THE COUPON Reference F. E. May benefit by mentioning the "Electrical Experimenter when writing to advertisers. ! 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