January, 1920 ELECTRICAL EXPERIMENTER 849

Your last chance to procure a com- The price goes u plete electrical ed- ucation at as low a price as $16,t1 payable $2 per month.

We had Intended to In- crease the price Nov. 29 last. but the Now York printers' strike prevented us from petting out our announce- ments.

The price of the CROFT LIBRARY OF PRACTICAL ELEC- TRICITY must go up. We have fought against this increase as long as we could. You have, however, one more chance to purchase at the old price. In fairness and justness to the readers of this paper, we desire to give everyone notice of the change in price before it goes into effect. Know electricity as experts know it No other library or course on the practical side of electricity adheres so closely to actual electrical work as the Croft Library of Practical Electricity. No other set of books or course is more modern, complete, or more easily understood. This Library, with its mine of working details, enables you to mastef electricity quickly,. and to know it as 'experts do. The standard in America Terrell Croft has had twenty years' experience in electrical practice. He started as wireman's helper. Later he became trouble shooter, then draftsman, then electrical engineer for the Westinghouse Co. His twenty years' experience is boiled down to eight flexibly-bound pocket books which are now accepted as the standard in America. Meet Terrell Croft Be guided in your study of electricity by an experienced electrical Nothing better at any price engineer of high professional standing, a man who gained his No matter how much you may pay electrical knowledge with his sleeves rolled up and has met your problems for literature, in advance. He tells in plain, understandable language how to nor how much you spend on educating yourself in the finer proceed by the best and most practical methods to the higher position. points of practice, you cannot get more reliable, more authori- tative, more detailed information than is contained in the Croft Library. It is an innovation in the world of electricity, as a ten -minute examination will prove. Ten days' free trial EXAMINATION COUPON NOT ONE CENT IN ADVANCE $ McGraw -Hill Book Co., Inc.. In order to receive advantage of the old price on these o) 239 W. 39th St., Now York. books, just fill out the coupon and return to us. Keep ': Gentlemen:- Please send me the Library of Practical Electricity the books ten days and examine them thoroughly, putting a (shipping charges prepaid), for 10 days' free examination. If satis- their usefulness to every imaginable test. Then if they are factory I will send $2 in ten days and $2 per month until $16 has been paid. If not wanted, I will write you for return shipping not satisfactory, return at our expense. instructions. Should they come fully up to your expectations, send us Name . $2 per month for eight months. Address McGraw -Hill Book Co., Inc. City and State 239 West 39th Street New York Where Employed

occupation (Ex. 1 -20) You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. Electricall Experimenter 233 FULTON STREET, NEW YORK Publisht by Experimenter Publishing Company, Inc. (H. Gernsback, President; S. Gernsback, Treasurer; R. W. DeMott, Sec'y), 233 Fulton Street, New York. Vol. VII. Whole No. 81 Contents for JANUARY, 1920 No. 9 FIRST WINGLESS AIRPLANE Front Cover ASTERN! "With Engine Running Ahead! 885 From a painting by George Wall By Charles M. Ripley VERTICAL LIGHTHOUSE BEAMS 867 POPULAR ASTRONOMY - THE EINSTEIN THEORY OF THE "HELICOPTER "-A VERTICAL AIRPLANE 868 RELATIVITY 886 By Robert G. Skerrett By Isabel M. Lewis, M.A., U. S. Naval Observatory IS THE ELECTRIC AIRPLANE POSSIBLE' 870 THE MOUNT WILSON 100 -INCH REFLECTING TELESCOPE - WHAT ATOMIC FORCES COULD DO 872 AND HOW BIG TELESCOPES WORK 888 ELECTRIC LOCOS CROSS ROCKY MOUNTAINS 874 By Professor F. L. Darrow MAGNETIC STORMS 876 THE STRUCTURE OF ELECTRICITY 892 By Professor Lindley Pyle By Dr. Alfred Gradenwitz SWIMMING POOL PURIFIED BY ELECTRIC RAYS ' 877 HOW DOES THE SUBMERGED LADY BREATHE? 893 H. IS THERE A SUB- ELECTRON? 894 By Joseph Kraus By Rogers D. Rush, M.A THE WORLD'S GREATEST THEATER 878 THE AMATEUR MAGICIAN -THE MAGIC FIRE BOWL 896 ELIMINATING SMOKE AND DUST ELECTRICALLY -HOW THE By Joseph H. Kraus SMOKE NUISANCE HAS BEEN ABATED AND MILLIONS PRACTICAL CHEMICAL EXPERIMENTS -INTERIOR HEATING 897 OF DOLLARS RECOVERED ANNUALLY FROM ORE -LADEN By Albert W. Wilsdon DUST IN SMELTING WORKS A SMALL RECTIFIER FOR CHARGING STORAGE BATTERIES 899 ELECTRICAL ENGINEER AT WORK 888801 By Elliott A. White By H. Winfield Secor CALIBRATING ELECTRICAL INSTRUMENTS 900 A MODEL "HELICOPTER" 883 By Thomas W. Benson By William John Beach, M.E. ELECTRICAL MACHINIST -No. 3.- REBABBITTING BEARINGS 903 SCIENCE IN LATEST MOVIES 884 By H. Winfield Secor

i A Ce eaaIlm 111111 IÍIfr Shoyl-CIlrcuIlt N Novetliber 26th there fell into Lake elapse. The entire cooling and subsequent heating Michigan a meteor of unprecedented process ranging from-459° to over 2500° Fahrenheit, which have since been probably takes place in less than 3 seconds. When size. Press reports anywhere verified thru a number of independent a really big meteor comes along weighing remarkable from 50 tons upward, it can be readily seen that the sources, reveal the following internal stresses must be enormous, because the core facts : while the shell may ball of fire, white may be at a temperature of-400°, Witnesses aver. they saw the great be in a molten state. Such a titanic difference in tem- and orange colored, which illuminated the whole coun- stresses, It fell peratures in a single body sets up ponderous try, pass over the lake south of Grand Haven. tending to rend the mass apart, which as a matter of into the waters, creating a fog of steam clouds. fact happens almost invariably. Telegraph operators of the New York Central lines things probably as Grand Rapids, In its flight earthward several other reported wire trouble as far north occur to a meteor, but as to these we are still ignorant. Mich. For one thing, due to the enormous friction set up, The power plant of the Calumet Electric Light Co., meteor prob- and another the writer advances the thought, that the at Kalamazoo was ,put out of commission, ably becomes highly electrified, taking on a charge that plant near Berrien Springs was disabled. runs into the millions of volts. Indeed there is no good The greater majority of the meteors which strike the reason to deny a strong charge even before the meteor earth are rather small, probably well below 100 lbs., for strikes our atmosphere. Remember a meteor is com- the individual fragment. Great meteors such as the posed of iron -nickel, a very excellent magnetic alloy. Peary Ahnighito, weighing 371/2 tons, are exceedingly Such a body without a shade of doubt must take on an rare. The composition of most of the known aërolites electrical charge when traversing any field of force, par- is iron with a small percentage of nickel. While the ticularly as it travels at such an enormous speed. The meteor moves thru interstellar space at the terrific old experiment of an unmagnetic iron rod which be- speed of from 18 to 36 miles per second, its tempera- comes a magnet when twirled around rapidly by means ture is that of free space, namely -459° Fahrenheit. of a string, is a case in point. The instant the meteor strikes the upper regions of Thus when the big meteor, probably as large or larger the atmosphere, the latter, acting like a cushion towards than a big mansion, struck Lake Michigan an immense the meteor, retards its flight. That means that an im- electrical force was liberated -a titanic short -circuit mense amount of heat is immediately generated, because it was in fact! The bottom of the lake forming the you cannot arrest a body traveling at such a prodig- "ground" or return circuit, it can be readily seen why ious speed without generating heat. But as the aërolite the electrical disturbances were not only felt for miles rushes earthward, the atmosphere becomes denser and around, but were of such a magnitude as to even burn denser, and the friction between the world wanderer out the big fuses of the electrical power plants. and our planet's air becomes enormous. That means The effect may be compared to the "return shock" still more heat -sufficient as a matter of fact to melt of lightning which often knocks down men and kills all or part of the iron- nickel mass. cattle, altho they may be at a considerable distance from From the time the meteor enters into our atmosphere the spot where the lightning hit. till it finally strikes the earth, only a few seconds H. GERNSBACK.

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The ELECTRICAL EXPERIMENTER is publisht on the 15th of each month at 233 tions are paid for on publication. A special rato is paid for novel experiments; good Fulton Street, New York. There are 12 numbers per year. Subscription price is $2.00 photographs accompanying them are highly desirable. a year in U. S. and possessions. Canada and foreign countries, $2.50 a year. U. S. coin ELECTRICAL EXPERIMENTER. Monthly. Entsred as second -class matter at the as well as U. S. stamps accepted (no foreign coin or stamps). Single copies, 20 cents New York Post Office under Act of Congress of March 3. 1879. Title registered U. S. each. A sample copy will be sent gratis on request. Checks and money orders should be Patent Office. Copyright, 1920 by E. P. Co., Inc., New York. The Contents of this drawn to order of EXPERIMENTER PUBLISHING CO.. INC. If you change your magazine are copyrighted and must not be reproduced without giving full credit to address notify us promptly, in order that copies are not miscarried or lost. A green the publication. . wrapper Indicates expiration. No copies sent after expiration. The ELECTRICAL EXPERIMENTER is for sale at an newsstands in the United All communications and contributions to this Journal should be addrest to: Editor. States and Canada; also at Brentano's. 37 Avenue de l'Opera, Paris. Sole British agents- ELECTRICAL EXPERIMENTER. 233 Fulton Street, New York. Unaccepted contribu- Geoffrey Parker & Gregg, 02 and 8A The Mall, Ealing, London. tions cannot be returned unless full postage has been included. ALL accepted contrlbu Member of the Audit Bureau of 'Circulation." ' 850 january, 1920 ELECTRICAL EXPERIMENTER 851

THIS ADVERTISEMENT Contains a Wonderful Message for Every Reader of The Electrical Experimenter

The message is of such extra- Mind is the Master Key which but you would not attempt to ordinary and transcendental im- unlocks the Secret Chamber in drive an engine with ice. Con- portance that no reader of this which the treasure is stored, and vert it into steam, and it easily magazine should fail to answer ideas are the seeds from which takes up the load. It is exactly it. It tells of the discovery of a abundance develops. Perception the same with Mental Ice. Con- reign of law, which has elimi- is the Magic Lamp which lights vert it into energy and it be- nated the element of uncertainty the way to opportunity, always comes a power so volatile, so and caprice from the lives of the invisible precedes and prede- subtle, so powerful, that it can men, and substituted law, reason termines the nature of the visible. readily control every other and certitude. The Infinity of Wisdom is a power in existence. Abundance is a Universal law. knowledge of the mechanism by The laws governing in the The evidence is conclusive. We which we are related to the law mental world operate with scien- see it on every hand. Every- of abundance. This knowledge tific exactitude, and those who where, Nature is wasteful, lavish, will enable us to consciously have become familiar with them extravagant. Profusion is mani- control our experiences and en- are enabled to break the bonds fested everywhere. Nowhere is vironment, compel opportunity of environment, control elemen- economy ob se r v e d in any and master fate, but we shall tary forces, and utilize the po- created thing. The millions and soon find that we cannot sow tentialities of Infinity. millions of trees and plants and seed of one kind and by "Will" The Master Key System is flowers and shrubs, the millions Power make it bear fruit of an- the only clear, concise, compre- of animals, the vast scheme of other. All Natural Laws obey hensive, definite, exhaustive, dis- production and reproduction us precisely to the extent that we tinctive, original and scientific where the process of creation first obey them. Power is there- presentation of this wonderful and recreation is forever going fore contingent upon a know- creative power ever formulated on, all indicate the lavishness ledge of the nature and opera- by anyone at any time. with which Nature has made tion of these laws. A copy of the Master Key provision for man. The creative Principle is in will be sent to any address with- That there is an abundance the Universal, and any attempt out cost or obligation of any for all is evident. The store- to force a compliance with our kind. house of Nature is inexhaustible. wishes by the power of the in- With this Master Key you If there appears to be lack any- dividual Will is doomed to fail- will be enabled to ascertain for where, it is simply an indication ure, because it antagonizes the yourself the underlying cause of that the channels of distribution very power which it is seeking every condition which ever has are as yet imperfect. to use. It is the individual in or ever will confront you, and Thought is the fuel which conflict with the Universal, the you will be surprised at the as- fires the imagination, which finite attempting to coerce the tonishing simplicity with which lights the torch of inspiration, Infinite, it is an inverted con- this Wonder Work, this Master- which controls the distribution, ception which cannot succeed. ful Idea, this Triumphant Teach- which turns the wheel of fortune, Water manifests on three ing is expounded. There is no from which your future will planes, as ice, as water and as charge for the Master Key, it is emerge. steam. It is the same compound, free!

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You benefit by mentioning the "Electrical Espe ncnter" when writing to adder sers.- 852 ELECTRICAL EXPERIMENTER January, 1920 LEARN WIRELESS By Mail -In Ten Weeks Calls Coming in Steadily for National Radio Institute Graduates from All Parts of the Country. Four Concerns Guarantee to Take All Operators We Can Furnish. Commercial Radio has arrived and many attractive positions are now open in the commercial land radio service, merchant marine, railroads, radio supply factories, lake and ocean steamship lines, telegraph com- panies and aerial mail service. We are now receiving requests for more National Radio Institute graduates than we can furnish. Salaries Up to $350 a Month Travel If You Want To with exceptional opportunity for promo- If you want to travel and see the world, tion to Radio Mechanics, Electricians, go to foreign countries and increase your Engineers, and Government Inspectors. No knowledge of world affairs, wireless offers previous experience or training is necessary. you the chance of a life time. However, You can learn Wireless the National Radio you are not obliged to travel, but may se- Institute way. in Ten Weeks, by mail, right cure a permanent position at one of the in your own home. With our help you can many land radio offices, railroads, tele- quickly qualify for First Grade Govern- graph or steamship companies, if preferred. ment License and a good position paying Pay As You Learn you approximately $2125 a month to start. Many of our students secure positions be- Our plans of payment places a wireless fore completing the course, because it is education within the reach of anyone who based on actual practice and teaches what desires to learn. is needed to make a big success of Wireless A small payment down on our convenient work. payment platt and small following pay- ments enables you to earn the cost of your Get Your Instructions from the tuition while actually learning to be a Nation's Capital wireless operator. (Our Course is Endorsed by the United FREE Instruments to Every States Government Officials) Student The National Radio Institute, established In addition to five text books-one hand book -46 special Lessons and 18 Personal Examina- in 1914, was the first in America to suc- tions-we send you, while taking our course, a is Standard Automatic Transmitting and Receiv- cessfully teach wireless by mail. It ing Set for sending and receiving messages. headed by authorities who have been close- These fine instruments are sent only to Nation- ly allied with government training of stu- al Radio Institute Students. dents. The work is under the direction of Free Membership in N. R. I. Relay J. E. Smith, E. E., formerly director of League the Radio Department, Howard University, Upon enrollment every student in the Na- tional Radio Institute is presented with a hand- and E. R. Haas, formerly of the Radio some blue and gold pin, signifying his official of Yale University, assisted by a membership in the N. R. I. Relay League, with Division a rapidly growing membership throughout the competent corps of trained instructors and world. lecturers. FREE Course in Radio Telephony We now have hundreds of students through- In addition to our complete course in radio out the world. Our location in the Nation's telegraphy, every student is given our complete Capital, together with the standing of our course in modern radio telephony. This course comprises ten special lessons and ten personal officers and their wide acquaintance among examinations. These combined courses enable government officials connected with Wire- our students to fill positions requiring thorough knowledge of both radio telegraphy and modern less activities, places us in position to give radio telephony. our students the best instructions obtain- able and to be of the utmost help in as- Send the following coupon today for our FREE book containing them to secure good paying positions. all particulars and sisting special offer to students enrolling now. NATIONAL RADIO INSTITUTE Dept. 152-14th and U Ste. N. W. Washington, D. C. Mail This Coupon Today -- -- NATIONAL RADIO INSTITUTE I Department 152, 14th & U Sts. N. W., Washington, D. C. Send me, free of charge, your booklet, "Wireless The Opportunity of Today ", with full particulars regarding your famous ten weeks' Home Study Course and your Special FREE INSTRUMENT OFFER.

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City State .. You benefit by mentioning the `Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 853

R' Try This Lesson Now

Take the ordinary longhand letter ír Elim- inate everything but the long downstroke and there RTA Simple Lessons will remain / This is the Paragon symbol for D. It is always written downward. letter .0 rub out every- yOU know how often you have wished that From the longhand you could write shorthand. You realized thing except the upper part -the circle -and your Can Now Be what it meant to busy executives and to will have the Paragon E. o business beginners-in efficiency, advance- Write this circle at the beginning of / and' Purchased for ment and increased earning power. you will have Ed. % But like thousands of others you dreaded the By letting the circle remain open it will be a hook, long, weary months of study, the memory tax, and this hook stands for A. Thus / will be the mental strain, and the high cost, in time and Ad. Add another,A at the end, thus a% and you ONLY money, of the old systems. will have a girl's name, Ada. Now you can have your wish. Because, all From eliminate the initial and final strokes) that you dreaded is done away with in the Para- O will which is the Paragon symbol Q5.ó0 gon Method of Shorthand. The entire system and remain, consists of for O.. For the longhand vvy which is made of 7 The Alphabet; Paragon strokes, you use this one horizontal stroke - Twenty -six simple word -signs; Therefore, -o would be Me. Six prefix abbreviations; Now continue the E across the M, so as to add Used In Government Service D- thus 7° and you will have Med. Noadd One general rule for contractions. "I learned Paragon Shorthand the large circle for O, and you will have o from the home -study course the - (medo), which is Meadow. with the silent A and W lessons alone - without any further THAT IS ALL. The simple explanations and aid whatever. At the end of a exercises are divided into seven lessons, each of omitted. week I could write the system which you can grasp in one evening. Speed will nicely. I am now using it in the develop pleasantly as you make daily use of your Government service, Treasury De- quickly acquired knowledge. partment, Washington. D. C., and telyou, William Loeb, Jr., Edward Bok and other am getting along O. K. On account This is the Paragon System. In 7 evenings men of highest achievement. of my efficiency as stenographer, you should easily learn it all. See for yourself my salary has been increased. I how perfectly simple it is. Stop right here and Shorthand Writers Wanted owe my rapid advancement to Para- study the specimen lesson at the right. Never before have American business men felt so gon Shorthand. " -E. C. ALLEY, Big Room 426, Winder Bldg., Wash- keenly the shortage of capable shorthand writers. Now you know how easy it will be for you to business houses are looking everywhere for shorthand ington, D. C. learn Paragon and how quickly you will be writers and are ready to pay any salary within reason to get the service they must have. Salaries are steadily ad- In Court Reporting equipped with the great modern instrument of for shorthand writers has Efficiency. vancing-and yet the demand "I have been the official Court not been supplied. Reporter for the Ninth Judicial Thousands of young, ambitious men and women District of Louisiana for a number who have failed to learn the old, complicated Speed, Simplicity and Accuracy of years, using Paragon Shorthand forms of shorthard have learned Paragon with are demanded of the shorthand writer by present-day exclusively. Some years ago I ease. business. With Paragon you can write without mental learned this system in seven les- friction-no complicated rules to remember, no "lines" to sons. With Paragon Shorthand I They have since become court stenographers, re- watch, no heavy and light "shading", only 26 simple am able to do any kind of work word -signs, no tedious memorizing, no confusing of mean- porters, assistants to business heads and in many old elimination of vowels. Paragon with as great rapidity as the oc- ings, through the cases notes never get "cold" they are just as easy to read after casion may demand. MAR- executives of prominent concerns and in- " -J. 10 years as after 10 minutes. TIAN HAMLEY, Lake Providence, stitutions. Thousands of grateful letters now in our files attest these facts. Those printed at the Our records show that in addition to the thousands of La. young men and women who need shorthand as a help in left are typical. men, In Public Schools their business careers, other thousands-business professional men, students, clergymen and literary folk - Paragon writers are all over the world, in Eng- $horthand as a time saving "As a result of competitive teats. would like to know Paragon land, Continental Europe, Australia, New Zealand, convenience. Still others-fathers and mothers -would Paragon Shorthand was unani- Canada, South America, Canal Zone, China, like to give their sons and daughters this wonderful ad- mously adopted as the exclusive vantage in order that they may be able to be self- support- system for the Atlanta High Schools. Philippine Islands and wherever English is ing any time it may be necessary. The classes we have already grad- spoken. Many of these persons who have not a direct need for uated in Paragon are by far the shorthand but want it as an instrument of efficiency and best we have turned out during my Paragon is used in the offices of the largest a daily time saver would buy the complete course of twelve years' connection with the firms and corporations in the world such as Paragon Shorthand at a popular selling price. schools. "-W. C. LOWE. Head of Standard Oil Company, United States Steel Corp- No the Shorthand Departments, 18 oration and the great Railway Systems. Send Money Avery Drive, Atlanta, Ga. Just fill out and return the coupon and Paragon Short- Paragon is also being taught in You have reached the point where you must hand Course will be immediately mailed to you. Try one the High Schools of Alton, Ill.; know Shorthand to do yourself justice and com- lesson or all seven, if you like. Keep the Course for seven Lafayette, Ind.; Johnstown, Pa, pete with others -as a busy executive or as a be- days -study it and test it from every point of view -then and elsewhere. decide whether or not it is worth $5.00 to you. If you ginner in business. don't want it you have not spent one cent and you are In Big Corporations You know how it is. Two good men apply for absolutely not under any obligation in returning it. If you decide to keep it send us only $5, and you will have "I am getting along fine with a position -one knows shorthand and the other received, for this small amount, the identical Course Paragon Shorthand. It is all you does not -the shorthand man wins every time. taught by Mr. Alexander Lichtentag for 15 years for $25. claim for it. It is easy to write, and as for speed- there's no limit." Remember how many of the biggest men in -JOHN WALLER, JR., Standard America got their start because they could write Paragon Shorthand Institute Oil Company, Sugar Creek, Mo. shorthand -Frank A. Vanderlip, George B. Cor- G1101 -311 Sixth Avenue, New York City

IMPORTANT G-1101 311 Sixth Ave., New York City With reasonable application you will have learned Para- PARAGON SHORTHAND INSTITUTE, gon at the end of a week. If your purpose is to use it for the making your own memoranda, you can then begin using Send complete Paragon it at once. But, if your object be to prepare for a short- Shorthand Course postage Name hand position, then, at the end of a week you will start prepaid. If not entirely speed practice to acquire the necessary speed. Numbers have been able to take positions In a month. two months satisfied, I will return it Business or three months. It all depends on the time per day within 7 days after its devoted to practice. In public schools, on account of many additional studies, the shorthand course Is made to receipt If I decide to Address last as long as the other courses -one or two years. keep it I will then send you $5.00 in full payment.

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. s 854 ELECTRICAL EXPERIMENTER January, 1920

NAME LUJLVJIVJLI/JIVJLVJLVJIVII\/JLVJVJJIVJLVJL VI J11,1/JIWDJLVJLVJWJlvJ0./JLVJPJJILVWJp,SRVJWJ ADDRESS I STATE . FILL IN THIS COUPON FOR E L E C T R O IMPORTING COMPANY, 231 Fulton St., New York City. I I enclose herewith 6 cents in stamps or e YOUR COPY OF coin for which please send me latest Cyclopedia Catalog No. 21 con- Our New 176 taining 176 pages, 263 illustrations Page Cyclopedia No. 21 and diagrams, including Treatise on Wireless Telegraphy, and IT IS WAITING FOR YOU 20 coupons for your 160 page Free Wireless Course in Full size fac- simile of our catalog as E 20 lessons. just it looks when you get It E. E. 1 -20 1 -2 INCH THICK . WEIGHT ALMOST 1 -2 POUND al In 263 Illustrations

A Few Interest - ing Things from Catalog No. 21 Treatise on Wireless Te- legraphy by H. Gerns- back, Editor Electrical Experimenter and Ra- dio Amateur News - 13 big pages, 3 illus- tralions. The Wireless Law of 1912-all about it, what you can do and what you can't. How to receive and send Radio messages. How far you can send messages. Table of wave lengths, of principal II. S. & foreign Radio high pow- er stations. How to receive time sig- nals by Radio. How to construct an amateur aerial. How to use the test buzzer. How to join the 'Radio League of America" FREE, including appli- cation blank. How telephone receivers are wound and built, tested and magnetized. 3 pages, 2 illustrations. Experiments with a pony telephone receiver, with 6 illustrations. Wireless Codes: Morse, Continental, Navy. Experiments with spark coils, 3 pages. E How to photograph elec- trical discharges (sparks). All about storage bat- teries, how to test them, recharging, etc. Teel a experiments, 2 pages. How to make Selenium Cells (illustrated). with this won- FREE derful cyclope- dia-20 coupons for our 160 page Wireless Course in 20 lessons. 3 5 0 illustrations, 3 0 tables. Catalog explains how you can get this Course absolutely free. "THE The Elpc h o Imnoaitjn Co. LIVEST 231 FULTON STREET NEW ORK CATALOG "EVERYTHING FOR THE EXPERIMENTER" IN AMERICA" IN this cyclopedia you will find 116 pages E. I. Co. for quality and workmanship. Talkers, High Frequency Apparatus and all about radio. One of the greatest Other things you will find listed in this supplies, Heating Pads, Electro- magnets, catalogs of its kind in print. catalog: Electrolytic Interrupters, Bull- X -ray tubes, Telephones, Magnetos, Low You will find in it dozens of wireless in- dog Spark Coils, Chemical Outfits, Omni - Tension Transformers, Books, etc., etc. struments of the famous E. I. Co. make. graphs, Code Practice Sets, Telegraph In- IN A WORD THE MOST COMPLETE Remember always that this company was struments, Primary Batteries, Storage Bat- CATALOG IN PRINT the FIRST to make and sell wireless instru- teries, Solenoids, Hydrometers, Volt and ments, the first wireless outfit having been Ammeters, Batterymeters, Electrolytic Rec- ELECTRO IMPORTING placed upon the market by in 1904. CO. them tifiers, Rheostats, Tesla Coils, Nickel Plat- 231 FVLTON STREET NEW YORK, N. Y. The E. I. Co. knows how, because it has the ing Outfits, Lighting Plants, Dynamos and experience. Others imitate but cannot equal Motors, Microphones, Detectiphones, Loud "Everything for the Experimenter"

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You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 855 January, 1920 ELECTRICAL EXPERIMENTER How One Evening's Study Led to a $30,000 Job A Simple Method of Mind Training That Any One Can Follow With Results from the First Day By a Man Who Made Formerly No More Than a Decent Living because they had been unable to remember just HOPE you don't think I'm conceited or -that is, if we read a book and remember what they wanted to say. Many decisions involv- tell how I nothing that was in it, we have not added ing thousands of dollars had been made unwisely egotistical in trying to others didn't remember all suddenly changed from a comparative one particle to our experience; if we make a because the man responsible about it, we are apt to the facts bearing on the situation and thus used failure to what my friends term a phe- mistake and forget poor judgment. I . know now that there isn't a nomenal success. make the same mistake again, so our experi- day but what the average business man forgets to so on, in everything do from one to a dozen things that would have in. I do not take the credit to my- ence did not help us. And greater words in In reality is absolutely dependent creased his profits. There are no self at all. It was all so simple that I believe we do. Our judgment the English language descriptive of business in- the same on our experience, and our experience is only efficiency than the two little words "I forgot." any man can accomplish practically had reached my decision. On the recommenda- secret, which he can do as great as our power to remember. I thing if he learns the My mind was a tion of Powers, I got in touch at once with the evening. In fact, I know others "Well, I was convinced. Independent Corporation, which shortly before had in a single never been able to re- Memory who have done much better than I by fol- `leaky pail'. I had published the David M. Roth Method of a man's name thirty seconds after I'd Training. And then came the surprise of my life. lowing the same method. member very first lesson of the course I found the been introduced to him, and as you know,I In the came about in a rather odd manner. key to a good memory. Within thirty minutes It all was always forgetting things that ought to be after I had opened the book the secret that I had I had been worrying along in about the same it as a fault, but never been in need of all my life was mine. Mr. Roth done. I had recognized the way as the average man, thinking that I was a definite barrier to business has boiled down the principles perfecting by providing thought of it as memory so that the method can almost be grasped doing my bit for the family in at once to make my you follow the meals a day, when an success. I started at a glance. And the farther them with three square memory efficient, taking up a memory training method the more accurate and reliable your mem- old chum of mine, Frank Powers, whom I a man's ory becomes. Within an hour I found that I could course which claimed to improve memorize a list of 100 words and call them had always thought was about the same kind you call my easily out with memory in one evening. What off backward and forward without a mistake. I of a chap as I, suddenly blossomed fortune to -day I attribute solely to my was thunderstruck with the ease of it all. Instead great prosperity. good seemed like a fascinating every evidence of exchanging a `leaky pail' for a mind that re- of study the whole thing a fine new house, bought a game: I discovered that the art of remembering He moved into tains the things I want to remember." had been reduced by Mr. Roth to the simplest good car and began living in the style of a * * * * * method imaginable -it required almost nothing but man of ample means. Naturally the first Powers' story set me thinking. What kind to read the' lessons! Every one of those seven when I noticed these things simple lessons gave me new powers of memory, and thing I did -for of a memory did I have? It was much the I enjoyed the course so much that I look back on he had said nothing to me about his sudden same as that of other people I supposed. I it now as a distinct pleasure. good fortune -was to congratulate him and had never worried about my memory one way The rest of my story is not an unusual one brought the evident change among American business men who have realized ask him what had or another, but it had always seemed to me the value of a reliable trained memory. My in- in his finances. I remembered important things pretty come today is close to $30,000. It will reach that that next fiscal year. "Bill," he said, "it's all come so quickly I well. Certainly it never occurred to me that figure at the beginning of our the And two years ago I scarcely made what I now can hardly account for it myself. But it was possible or even desirable to improve think of as a decent living. thing that has made such difference in my it, as I assumed that a good memory was a In my progress I have found my improved mem- life lately began with an article I read a short of us, when ory to be priceless. Every experience, every busi- sort of natural gift. Like most ness decision every important name and face is time ago about training the mind. I wanted to remember something particularly easily and definitely recorded in my mind, and each "It compared the average person's mind to I wrote it down on a memorandum pad or in remembered experience was of immense value in leaky losing its contents as it went then I would some- my rapid strides from one post to another. Of a pail, a pocket notebook. Even course I can never be thankful enough that I along, which if carried any distance would times forget to look at my reminder. I had mended that "leaky pail" and discovered the arrive at its destination practically empty. been embarrassed -as who has not been ?-by enormous possibilities of a really good memory. "And it showed that instead of making the being obliged to ask some man whom I had SEND NO MONEY it up was, after vain- pail leak -proof most of us kept filling previously met what his name Mr. Roth's fee for personal instruction to classes and then losing all we put into it before we ly groping through my mind for it, so as to limited to fifty members is $1,000. But in order to ever reached t h e be able to introduce him to others. And I secure nation -wide distribution for the Roth Mem- place where the had had my name requested apologetically for ory Course in a single season the publishers have David M. Roth put the price at only five dollars, a lower figure contents would be the same purpose, so that I knew I was no kind has ever been sold When Mr. Roth first de- than any course of its termined to exchange his of real use. different than most men in that way. before, and it contains the very same material in leaky mind for one that observe myself more closely in permanent form as is given in the personal $1,000 would retain anything he "The leak in the I began to course. wanted It to. It was be- pail, the writer dem- my daily work. The frequency with which I So confident is the Independent Corporation, the cause he found his mem- Roth Memory Course, that once ory to be probably poorer onstrated, was for- had to refer to records or business papers con- publishers of the than that of ally man he getfulness. He show- cerning things that at some previous time had you have an opportunity to see in your own home knew. He could not re- how easy it is to double, yes triple the powers of member a coat's name ed that when mem- come under my particular notice amazed me. your memory, and how easily you can acquire the 20 seconds. He forgot so ory fails, experience, The men around me who were doing about secret of a good memory in one evening, that they maay things that he wan to on free examination. convinced he could never the thing we all the same work as myself were no different are willing send the Course succeed until he learned Don't send any money. Merely mail the coupon to remember. Today there value most highly, than I in this regard. And this thought gave or write a letter and the complete course will be are over ten thousand is worthless. He new significance to the fact that I had been sent, all charges prepaid, at once. If you are not people in the United entirely satisfied send it back any time within five States whom Mr. Roth proved to me that performing practically the same subordinate it and you will owe nothing. has met at different times same salary for some days after you receive -most of them only once a man is only as duties at exactly the On the other hand, if you are as pleased as are -whom he can instantly good as his memory, three years. I couldn't dodge the fact that the thousands of other men and women who have name on eight. as well as most other people's, lit- used the course, send only $5 in full payment. You Mr. Roth can and has and whatever prog- my mind, take no risk and you have everything to gain. so hundreds of times at din- ress erally limped along on crutches, because it offer ners and lectures asked a man accom- mail the coupon now before this remarkable fifty or sixty men he has plishes can be laid could not retains names, faces, facts, and fig- is withdrawn. never met to tell him their to if even a EXAMINATION COUPON names. businesses and directly to his pow- ures. Could I expect progress FREE telephone numbers and ers of retaining in small proportion of the important things I then after turning his hack while they changed his mind the right learned from day to day slipped away from Independent Corporation seats. has picked each one things the things me? The only value of most of my hard -won Publishers of The Independent Weekly out by name. told him - his telephone number that are going to be experience was being canceled-obliterated- Dept. R1101 119 West 40th'St., New York and business connection. forgetting things that my These are only a few of useful to him as he by my constantly Please send me the Roth Memory Course of the scores of equally "Im- goes along. experience had taught me. seven lessons. I will either remail the Course to possible" things that Mr. The whole thing hit me pretty hard. I began to you within five days after its receipt or send you Roth can do. and yet a "Farther on in $5 of the Course. few years ago he couldn't think about the subject from all angles as it af- in full payment remember a man's name the article I read fected our business. I realized that probably hun- twenty seconds. WM go that the power of dreds of sales had been lost because the salesman Name around with a mind like a forgot some selling point that would have closed leaky pail When. as Mr. the mind is only whom I had heard Address Roth says. "what r have the order. Many of our men done any one can do." the sum total of try to present a new idea or plan had failed to put what we remember over their message or to make a good impression Elect. Exp.-1.20 You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 856 ELECTRICAL EXPERIMENTER January, 1920

e Rule That Makes Selling Easy

How I Learned It in A Few Hours and Became a Super -Salesman

YOUNG fellows who take to ing business and the opportunity to our business and I had much to do office work are not usually of pile up to my credit a daily record with the routine end of this work. the type who are interested in of work well done. I naturally became interested in the salesmanship. I was no different As I look back now I can see that kind of men who could or could not from ; the rest my natural bent, my my viewpoint was that of the loyal sell to our firm. The daily contests future, semed to be on the "inside." subordinate who works faithfully, between buyer and seller were ab- As jobs go I had a fair one. I but without a fixed purpose. Like sorbingly interesting to me. had the good fortune to be thrown many other young men, I had plenty One question which perplexed in contact with two unusually high- of hope, which I mistook for ambi- me, and to which I find tion. could not grade business men. From them I an answer, was, "What made a first - had the chance to learn an interest- Purchasing was a vital factor of class salesman ? Why were some You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1 92 0 ELECTRICAL- EXPERIMENTER 857 salesmen inefficient ? Could 1 be a of lightning I was well nigh para- on the road. Right from the start salesman of any kind -good, fair or lyzed with Revelation I possessed I sold goods in substantial quanti- poor ?" I often wondered. But that the one, the all- embracing, Rule that ties. In nine short weeks my sales was as far as I got. The possibility would make me, bashful clerk that I topped the list of our entire selling of actually becoming a super- sales- was, a super -salesman.. force. You can well imagine my man no more struck me than the . jpy. I had actually out- distanced possibility of my becoming a beau- Though I may have a thousand "Old Timers" and had become the tiful butterfly. future lives to live, I believe that I firm's Super - Salesman. That is, until the night of what I But for what I have done I claim call The Great Revelation, when - no special ability. I had only a But I am getting ahead of my story. grade - school education, and never was considered anything out of the My employers were not easy peo- ordinary intellectually. I say this ple to sell. Besides being accom- frankly, as I have no desire to pin plished buyers they were human roses on myself. beings with likes and dislikes, preju- dices and whims. Mr. Pond was The point I want to make is this : rather overbearing and could be very If I, with these handicaps, could so tyrannical. Mr. Booth was our quickly become a top -notch sales- scholar-quiet and cold, oversensi- man, it is only reasonable to suppose tive and refined. Anything crude or that others can, too. The thing that noisy grated upon him. so quickly made me a Master Sales- man was a knowledge of The One I soon found that all the salesmen Great Rule in Selling and Its Hun- who called upon us could be classi- Who Is dred Devices, told by Arthur New- fied into three types : First, and in Arthur Newcomb? comb in his astounding 7- Lesson the large majority, were the incom- Course in Super -Salesmanship. petents. They generally went away After his graduation from college Every word of this great course empty- handed. Occasionally, out of Mr. Arthur Newcomb took up news- pity, Mr. Pond would give one of paper work, and in the ten years from is written out of practical achieve- 1896 to 1906 was reporter, city ed- ment in is them a little order. But all men of itor, news editor, managing editor, selling. That why it special correspondent, advertising man- stands out from the legion of books this type ever got from Mr. Booth ager, manager,.and advertising coun- sellor for various newspapers and pe- and courses on selling. was a quick application of high -bred riodicals. freezing process. He had nothing In 1909, he edited the course in No preaching, no teaching, no but contempt for inefficiency. "The Science of Business Building" theorizing, no tricks, no stunts. But of which fifty thousand copies were the - of the sold in the eight years following. one hundred clean -cut, easily The second class consisted understood devices that will speedily medium -grade salesmen. These In 1912-13, Mr. Newcomb edited "The Science of Personal Efficiency." get you under, over, around and men were turned down, however, through the obstacles to triumphant oftener than they got orders. And In 1914, in collaboration with Dr. K. M. H. Blackford he wrote `The selling achievement. I noticed this -that those who could Job, The Man, The Boss," which not only had a phenomenal sale, but set sell to Mr. Pond were often unable in motion the great employment move- ment which has since been adopted by to get anywhere with Mr. Booth. It the United States Chamber of Com- You need not take anyone else's was the other way around, too. merce and the United States Gov- ernment. word for what the One Great Rule who ever of Selling will do for you. You can Out of all the salesmen In 1913.14, he edited "Character An- be the called upon us there were only alysis by the Observational Method," judge yourself. Send no by Dr. K. M. H. Blackford and, in money. Mail the coupon. This will about five who nearly always made a 1915, collaborated in writing "Ana- lyzing Character," both of which works bring the complete Course to you on sale. They seldom went away have had a very wide sale. empty- handed. Nor did they talk five days' approval. Examine it In 1918 Mr. Newcomb edited, for thoroughly ; test it out in actual ex- much nor work at all hard to make Dr. Blackford, the short course, "Reading Character at Sight," now perience. Then if you feel that you a sale. They made up the third being studied by tens of thousands. class -the Master Salesmen. can get along without it, send it back In his Course, "Super- Salesman- and you will owe nothing. But if ship," Mr. Newcomb has broken away How did they do it? I did not from all the old traditional theories you want to make it yours, as you of salesmanship and persuasion - know then. But now I know that which made such a wide appeal and had surely will, remit only seven dollars consciously or unconsciously they so much good effect because they were in full payment. partly true -and has based his work used The One Great Rule of Suc- upon human nature as it is and upon the world's greatest commanders, As this special free -trial offer cessful Selling. Even though these leaders, and salesmen. Mr. Newcomb may be withdrawn at five men expressed themselves dif- has been a salesman and salesmana- any time, it is ger. He has employed and trained suggested that you take prompt ferently and were entirely different hundreds of salesmen and knows ex- actly the problem salesmen must solve action and mail the coupon now. types of men, they all used The One and how to solve them. In all his Rule. men experience Mr. Newcomb has found Great And the who but one great rule for selling goods INDEPENDENT CORPORATION failed to sell to is did not use this of any description. Dept. S 1101 rule. 119 West 40th Street, New York City But let me tell you how I found INDEPENDENT CORPORATION, this out. One day I ran across some- can never forget those wonderful Dept. S -1101, 119 West 40th Street, New York thing in print on salesmanship. I moments when I first read of The City. Please send me Arthur Newcomb's Course in had never taken printed matter on One Great Rule of Successful Sell- Super- Salesmanship on 5 days' Approval. If salesmanship at all but for ing and Its Hundred Devices. It pleased with it I will send you $7 in full pay- seriously, ment for it- otherwise I will return the Course. some reason or other this gripped was mighty knowledge to have and my attention. use. Name

Then came the interest that no To make my story short, I "sold" Address novel can give. With the swiftness my firm on the idea of sending me Elec. Exp. 1-20 You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 858 ELECTRICAL EXPERIMENTER January, 1920 MAGA2INie Príce $1ahedï of magazine subscriptions expire this month! With the tremendous advance of paper prices and labor it is Millions certain that nearly all magazines will advance their subscription prices at least from 25% to 50%. The BY ORDERING NOW YOU WILL SAVE BIG MONEY. }¡Yiaav. In announcing these wonderful prices it is with the absolute, Publishers knowledge that our readers are offered the lowest prices for standard Magazines that it is possible to obtain anywhere. Will Mail the Only by special arrangement with the publishers are these prices possible, but to take advantage of them, Magazine you must act quickly. Don't delay, do it now. 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You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER1 859 - ,YCCA-c.-..- J wi 1Et71tY l¡q vir VOL.! Yl? l ,

C>!N itEClk t*)

LLN MtqjLAY' nM ipQ:tM1 YilaeM1JL Learn Electricity the New War IT'S no longer necessary to go to school or serve an ap- This is the 1920 edition-new from cover to cover -chuck prenticeship to learn electricity. With this new library full of the latest methods and most recent discoveries in of APPLIED PRACTICAL ELECTRICITY you learn this fascinating field. Everything is written in plain, good right at home -in your spare time without interfering old U. S. language by 27 of the greatest experts in the busi- with your present work. ness. The eight volumes with 3800 pages make up a com- Any big job that you want in the electrical field is yours plete course in electrical engineering. It's a home study if you will train yourself to fill it. It only takes an hour course for the beginner and a handy reference guide for or two a day with these books. the expert combined. Big Par for Jobs paying Good Jobs If you are the Elements of What Electricity - Trained Men $5000.000 í a Are Waiting some branch Books Teach Electrical year are waiting for men who can of electricity you will never have to look Measurements -Electric Wiring -Un- qualify as Electrical Engineers -Sub- for a job. The job and the big pay will derwriter's Electrical Requirements - station Operators -Troublemen- be looking for you. You can't dodge a Theory, Calculation, Design and Con- Switchboard Operators -Dyna moTend- good job if you have the "know how" struction of Direct Current Generators ers- Electricians. Electricity is the under your hat. Let these 27 great en- and Motors-Types of Generators and greatest force in the world and it is gineers help you to the best kind of job Motors -Management of Electrical Ma- growing bigger and bigger every day. with their books. chinery- Electric Lighting -Alternating More and more men are needed all Send the coupon below and get them Current Machinery-Power Transmis- the time. Why don't you get into for FREE examination. See our free sion- Electric Railways-Self- Propelled this big paying field now? offer below. RailwayCars- TracklessTrolley -Power Stations -Switchboards and Switching- Storage Batteries-Applied Electro-chemistry - Electric Elevators-Electric Welding and Heat- The World's Greatest ing- Wireless Telegraphy and Telephony - Land and Submarine Telegraphy. With every set Free Service of these great Electrical Books electrical books we give a one year membership in this society. This entitles you to consult our engineers and experts on any electrical prob- lem. Write as often as you like. Ask as LOANED to YOU many question as you like for one year. I Coupon is American FREE Technical We will lend you this wonderful library to use in your own home or shop a All You Society whole week FREE. It won't cost you one cent. DON'T SEND ANY MONEY. De.t. E-251 Just fill out and mail the coupon today and the set of eight volumes will come Need Chicago. U. S. A. I to you by express collect. You be the judge and find out for yourself what the Please send me the 8 -vol- nLne set of Electrical En- I books will do for you. Use them as you please. Show them to your friends gineering for? days' examin- and get their opinion. Then if you have any doubt as to their value send them Send it ation, shipping charges collect. If I decide to buy I will send $2.00 back at our expense and you won't owe us anything. Now within 7 days and balance at the rate of $2.00 a month until $24.80 has been paid. Then you will send me a receipt showing that the set of books DIV and the Consulting Membership are mine OnIY 7 Cents a pay and fully paid for. If I want to get along If you like the books after a week's examination you pay us only $2.00 and the same amount without the hooks, I will return them, after each month until $24.E0 is paid. This is only 50 cents a week -7 cents a aay. You can't afford 7 days, at your expense. to pass up a better job on these easy terms. MAIL THE COUPON NOW. American Technical Society Asme Dept. E -251, CHICAGO Address lejere,Lee

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 860 ELECTRICAL EXPERIMENTER January, 1920

"I was astonished at my new power over men and women. People actually went out of their way to do things for me, they seemed EAGER TO PLEASE ME. The Secret of Ma/tiny People Like 61612,

"Getting people to like you is the quick road to Peters ! Why, this fellow Peters was success -it's more important than ability," only a branch -office salesman. . . says this man. It surely did wonders for him. Personality! Why, he was only five feet four inches high, and had no more How he does it -a simple method which any- personality than a mouse. Stack him one can use instantly. up against a big man and he'd look and act like an office boy. I knew ALL the office was talking about it, ways. And I was sure that the firm Peters well and there was nothing to and we were wondering which one knew it, too. him, nothing at all. January the first came and Peters of us would be the lucky man. Never shall I forget my thrill of assumed his new duties. All the boys There was an important job to be filled pleasure when the president's secretary were openly hostile to him. Naturally, Assistant -to- the -President. Accord- came into my office with a cheery smile, -as I felt very keenly about it, and did not looked at me meaningly, handed me a ing to the general run of salaries in the exactly go out of my way to make things bulletin and said, "Mr. Frazer, here is office, this one would easily pay from pleasant for him -not exactly! the news about the new Assistant- to-the- $7,000 to $10,000 a year. But our open opposition didn't seem President." There seemed to be a new The main requisite, as we to bother Peters. He went right on with understood note of added respect in her attitude his work and began to make good. Soon it, was striking personality and the abil- toward me. I smiled my appreciation I noticed that, despite my feelings ity to meet even the biggest men in their as she left my desk. against him, I was secretly offices, their clubs, and their homes on a beginning to At last I had come into my own! admire him. He was winning over the basis of absolute equality. This the firm Never did the sun shine so brightly as other boys, too. It was not long before considered of even more importance than on that morning, and never did it seem we all buried our little hatchets and knowledge of the business. so good to be alive ! These were my palled up with Peters. You know just what happens when thoughts as I gazed out of the window, The funny thing about it was the big news of this sort gets around an office. seeing not the hurrying throngs, but hit he made with the people we did The boys got to picking the man among vivid pictures of my new position flash- business with. I never saw anything themselves. They had the choice all ing before me. And then for a further like it. They would come in and write narrowed down to two men -Harrison joyous thrill I read the bulletin. It in and telephone in to the firm and praise and myself. That was the way I felt said, "Effective January 1, Mr. Henry Peters to the skies. They insisted on about it, too. Harrison was big enough J. Peters, of our Cleveland office, will doing business with him, and gave him for the job, and could undoubtedly make assume the duties of Assistant-to-the- orders of a size that made up dizzy to a success of it. But, personally, I felt President at the home office." look at. And offers of positions! -why, that I had the edge on him in lots of Peters ! Peters-surely it could not be Peters had almost as many fancy- You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 861 figure positions offered to him as a dic- Then trouble sprang up at one of our you will quickly become a leader - tionary has words. factories. Then men talked strike. nothing can stop you. And you will What I could not get into my mind Things looked ugly. I was sent to want to use it for no other reason than was how a little, unassuming, ordinary - straighten it out. On the eve of a gen- to protect yourself against others. to- look -at-chap like Peters could make eral walkout, I pacified the men and What Peters told me at luncheon such an impression with everyone-es- headed off the strike. And not only this, that day was this: "Get Dr. Blackford's pecially with influential men. He seemed but ever since then this factory has led `Reading Character at Sight.' " I did to have an uncanny influence over peo- all our other plants in production. so. This is how I learned to do all the ple. The masterly Peters of today was I could tell you dozens of similar remarkable things I have told you about. an altogether different man from the instances, but they all tell the same You have heard of Dr. Blackford, the commonplace Peters I had first met story -the ability to make people like Master Character Analyst. Many con- years ago. I could not figure it out, nor you, believe what you want them to be- cern:: will not .employ a man without could the other boys. lieve, and to do what you want them to first getting Dr. Blackford to pass on do. I take no personal credit for what I him. Concerns such as Westinghouse One day luncheon at I came right have done. All the credit I give to the Electric and Manufacturing Company, out and asked Peters I how he did it. method Peters told Baker -Vawter Company, Paper half expected him to evade. But Scott he me We Company and many others pay Dr. didn't. He let me in on about. the secret. He have told it to lots Blackford large annual said he was not to fees for advice afraid do it as there of our friends, and on dealing was always plenty with human nature. of room at the has top. it enabled So great was the demand for these them to do just as services that Dr. Blackford could not What Peters told remarkable things even begin to fill all the engagements. me acted on my mind as Peters and I So Dr. Blackford has explained the in exactly the same have done. method in a simple seven-lesson course way as when you Which reminds entitled "Reading Character at Sight." stand on a hill me: One of my Even a half hour's reading of this and look through wife's close friends remarkable course will give you an in- binocular glasses moved to another sight into human nature and a power at objects in the she people " People would come in and town where over which will surprise you. far distance. write in and telephone in and was a stranger. Such confidence have the publishers praise Peters to the skies . . Many things I he was showered with offers course of fancy figure positions." My wife of in Dr. Blackford's course, "Reading could not see be- knew of my meth- Character at Sight," that they will fore suddenly od. She told it gladly send it to you on approval. Send leaped into my to her friend with the idea that it might no money. Merely fill in and mail the mind with start- be of assistance to her in meeting new coupon. The complete course will go to of power ling clearness. A new sense people. It helped her so wonderfully you instantly, on approval, all charges the urge surged through me. And I felt that in a very short time she won the prepaid. Look it over thoroughly. See to put it into action. close friendship of many of the "best if it lives up to the claims made for it. Within a month I was getting re- families" in the town. Every one won- If you do not want to keep it, then markable results. I had suddenly be- ders how she did it. But WE know. return it, and the transaction is closed. come popular. Business men of impor- But you want to know what method And if you decide to keep it-as you tance who had formerly given me only I used to do all these remarkable things. surely will -then merely remit Five a passing nod of acquaintance, suddenly It is this: You know that every one Dollars in full payment. showed a desire for my friendship. I doesn't think alike. What one likes an- Remember, you take no risk, you was invited into the most select social other dislikes. What pleases one offends assume no obligation. The entire course circles. People -even strangers -actu- another. And what offends one pleases goes to you on approval. You've every- ally went out of their way to do things another. Well, there is your cue. You thing to gain -nothing to lose. So mail for me. At first I was astounded at my can make an instant hit with any one if the coupon NOW, while this remark- new power over men and women. Not you say the things they want you to able offer remains open. only could I get them to do what I say, and act the way they wanted them to do but they actually want you to act. Do this and anticipated my wishes and seemed eager they will surely like you, to please me. But let me tell you some and believe in you, and will of my experiences. go miles out of their way to One of our biggest customers had a PLEASE YOU. grievance against the firm. He held off You can do this easily by payment of a big bill and switched to knowing certain simple signs. one of our competitors. I was sent to Written on every man, woman see him. He met me liked a cornered and child are signs, as clearly tiger. A few words and I calmed him. and as distinctly as though Inside of fifteen minutes he was shower- theywere inletters a foot high, ing me with apologies. He gave me a which show you from one quick check in full payment, another big or- glance exactly what to say and to continue giving to do `In a very short friendship of mane der, and promised to please them-to get f the 'beat families' in t us all his business. them to believe what you want iti - -FREE EXAMINATION COUPON-' For certain reasons it became neces- them to believe-to think as for the firm to obtain a signed let- you think do exactly what Independent Corporation sary -to Weekly man. Three you want them do. Publishers of The Independent ter from a prominent public to Dept. B -1101 119 West 40th St.. New York of our men had tried, and failed. Then In knowing these simple You may send me Dr. Blackford's Course of seven les- sons entitled "Reading Character at Sight." I will either I was given the job. I felt I had been signs is the whole secret of get- remall the course to you within five days after its receipt. made the "goat." But I got the signed ting what you want out of life or send you $5 in full payment of the course. letter, and with it an inside tip which -of making friends, of busi- Name enabled us to land a prize order about ness and social advancement. Every Address which our competitors are still guessing great leader uses this method. That is and wondering. why he IS a leader. Use it yourself and Elec. Ewer. 1 -20 Von benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 862 ELECTRICAL EXPERIMENTER January, 192G

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Talklc- y and others will In- stantly get your point of view -think as you do -and carry out your slightest wish. '771e Knack of Talking Convincingly

IN nearly every group of men there is speech. Many of us deserve a greater salary what your ability entitles you to, you've got one good talker. He is always the than we are getting. You may have a won- to know how to talk convincingly. derful ability genius for your work -which leader. Convincing talkers are the -a You have seen or read about scores of courses dominating leaders of every business. is not being rewarded because you can't put which claimed to teach convincing speaking. You Here's how you can learn the principle your ideas into speech that convinces. Do not have often thought you would like to take ad- let this handicap hold you back another day vantage of them and master this knack of powerful of convincing speech in one evening and speech. Possibly you have investigated a few of rise quickly to leadership. from the success that is rightfully yours. them. But you have always found one of two the time comes is al- have felt as elated When -and opportunity things. Either the course in question dealt almost IWONDER if you would ways at hand-you can be ready to get up entirely with oratory -for which you have no use - as I did. A man whose name you would or else you discovered that the price was entirely be- in the financial world and put your thoughts into speech, the sheer yond what you wish to pay for such training. know instantly -a power force and conviction of which will mark you -had granted me an interview. I wanted secret of his great success. as a leader. here at last is a wonderful new method of him to tell me the This knack of talking convincingly will do BUTteaching the principles of convincing speech. Put yourself in my place if you can, and for It is not instruction in oratory or the use of high - -mil- wonders any man or woman. Most people sounding words. But it shows you in one evening imagine yourself seated before this multi are his boyhood, afraid to express their thoughts; they the principles of talking your way to a better posi- lionaire, chatting with him about know the humiliation tion, more salary and success. And the price his meteoric rise. of talking to people and -not his start in business and obtaining in answer a casual nod, or a curt twenty, thirty or forty dollars -but FIVE. He was the biggest man I had yet inter- Not one cent in advance. You examine it free - "yes" or "no ". But when you can talk con- viewed in the hope of getting a real "half vincingly, it's different. When you talk, peo- for five days. Then if you want to keep it, send five Nelson" on the illusive "secret of success." I dollars. If you do not want it, send it back and the ple listen to you. you are not out a penny. We take all the risk. had half expected to hear When you have acquired the Send no money. Merely mail the coupon and the same old story about "honesty, knack of talking convincingly, it's complete course goes to you at once. hard work and stick-to- itive- Can You Do This? This course was written by Dr. F. H. Law, for easy to get people to do any- thirty years a lecturer and an authority on speech. ness." So you can imagine my Can yo u talk as to You he said that his well in pu blic as at thing you want them do. When you receive Dr. Law's course, it will be just surprise when home? can get special attention from the same as if you were in personal contact with success was due primarily to one Can you get finan- Dr. Law, getting the benefit of his advice and in- words: anyone from a hotel clerk up to struction. thing. To use his own cial back ing when a millionaire. You can make "If you should ask me what you want it? In one evening you will get the secret of talking - others see your point of view, advice I would give every young Can you win con convincingly. You will learn exactly how to secure fidence, friendship, think as you do, and carry out complete attention to whatever you are saying; how man in business, I would say, love thro ugh your to make your words forceful and convincing, speech? your slightest wish. and `Learn to talk convincingly.' All again it helps in make other people do for you the things you want is upon Can y ou make And social done. success in business built people lis ten when life. Interesting convincing others to think and do and Many men have risen to leadership through the getting you talk? talk is the basis of social success. as wish getting the will- Can you hold your use of Dr. Law's wonderful course, "Mastery of you -in At social affairs you will always Speech." It may be your "open sesame" to a big ing co- operation and loyal sup- hearers sp ell bound? Can you give hu- find that a convincing talker is success. If you do not want it you cannot lose a port of other men. And the only morous, e xtempora - and cent. Don't send any money in advance Just mail way this can be had is through neous talk s? the center of attraction that the coupon. The whole course goes to y at once. becoming a convincing talker." Can yo u address people go out of their way to Remember what the multi -millionaire said : any size audience to him. Talk con- "There is no ability which will bring success to "There is no ability which will "make up" from one to thou- vincingly no man mat- a man so quickly as the ability to talk convincingly." bring success to a man so quick- sands? and -no ter who he is -will ever treat Strike out now with a strong determination for ly as the ability to talk con- Can yo u get up your success. Mail the coupon today. vincingly." and talk, any time, you with cold, unresponsive in- any place without difference. Instead, you will in- Free Examination Coupon And the more men I see who nervousne ss? have made their marks in the stantly "get under his skin." Talk world, more I realize that he convincingly and any man -even INDEPENDENT CORPORATION tie like an pal was right; They are all convincing talkers. a stranger-will treat you old and Publishers of the Independent Weekly the shirt off his back" to With their mastery of words, their ability to will literally "take Dept. L -1101, 119 West 40th Street, New York talk convincingly, and with the dominating please you. You may send me Dr. Law's course, "Mastery of influence of their speech, they have swept Speech." I will either remelt the entire course to away all barriers and have attained success. OU can get almost anything you want if you within five days after its receipt or send you I you know how to talk convincingly enough. $5.00 in full payment for the course. ability alone IT is no figure of speech, but fact, to say that You've noticed that in business, Name the great men have talked themselves does not always count. Many a man of real himself well, is to success. ability, who cannot express Address . .' Many a man who deserves success is being outdistanced by a man of mediocre ability held back because he can not express his who knows how to talk convincingly. There's City State thoughts and ideas in strong, convincing no getting away from it, to get ahead -to get Elect. Exp. 1 -20 You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 864 ELECTRICAL EXPERIMENTER January, 1920 IERISTRY

/NM

. No. *1 469' G

t '_Li . Imo 0 IlD «ai 'Nor It contains the follow- . ing 44 chemicals: Mum Al2(SO4)2, (NH4)2SO4 Antimony (powdered) (Sb) Ammonium Aqua (NI- 13-1-H20) Ammonium Carbonate (NH4)2 CO2 Ammonium Chloride (NH4CI) "TILe Joy of Fatlicr and Boy." Ammonium Sulphate (NH4)2 SO4 Barium Chloride (BaC12) Boric Acid (HaBOs) Brimstone (Sulphur) (S) Calcium Chloride (CaCI,) Calcium Oxide (CaO) Calcium Sulphate Chemical Laboratory (CaSO42 H2O ) Charcoal (Carbon) (C) Chloride of Zinc (ZnC12) We present herewith to our friends our new E. I. Co. Chemical Labora- Copper Sulphate (CÚS04) tory which contains real chemicals and apparata to perform real chemical Ferrous Sulphate (FeSO4) Ferrous Sulphide (FeS) experiments. This outfit is not a toy, put up merely to amuse, but a Glycerol (Glycerine) CsH2(OH)a practical laboratory set, with all the chemicals, apparata and reagents Hydrochloric Acid (HCI) necessary to perform real work and to teach the beginner all the secrets Iodine (1) Iron Chloride (FeCl2) of inorganic chemistry. With this outfit we give free a book containing Iron Oxide (Fe2O3) useful and recipes, and 100 Lead Acetate Pb (C2H802)2 a Treatise in Elementary Chemistry, data Litmus Paper instructive and amusing experiments. Magnesium Carbonate (MgCO3) Manganese Dioxide (MnO2) DESCRIPTION OF THE OUTFIT: Mercury (Quicksilver) (Hg) Nickel Chloride (NiC12) The outfit consists of forty -four (44) Chemicals all A good part of the book is devoted to Weights and Oxalic Acid (H2C204) C. P. (chemical pure) put up in appropriate wooden Measures. The Metric System, the English system Sodium Bicarbonate boxes, glass bottles, and hermetically closed jars. The and the U. S. System are fully explained. (NaHCO3) acids are put up in glass bottles, with ground -in glass Sodium Borate (NaBO2) stoppers and there is a sufficient quantity of chemicals The following tables are furnished: Symbols and Sodium Carbonate (Na2CO2) supplied (mostly one to two ounces) enough to make Atomic weights of the Elements; Measures of Weights, Sodium Chloride (NaCI) dozens of experiments with each. See list of Chemi- Volume, Capacity and Length; Per Cent solutions; Sodium Nitrate (NaNO3) cals herewith. Conversion of Measure expressed in parts; Poisons Sodium Phosphate The apparata furnished are all of the best obtainable and their antidotes; Technical and common name of (Na2HPO4) make and of standard laboratory size and shape. A various list of the 17 ieces of apparata furnished with this chemical substances; Formulas for Cleaning Sodium Sulphate (Na2SO4) etc. Sodium Sulphite (Na2SO2) outfit is printed also herewith. substances, etc., book Stannous Chloride (SnC12) The Instruction is a real Chemistry Course Among the 100 Experiments are: Sulphate of Nickel (NiSO4) for the Beginner. Some of the Contents are: Divi- Sulphate of Zinc (ZnSO4) sion of Matter: This is a Treatise on Elementary How to make chemical tricks; How to make invisible Sulphuric Acid (H2SO4) Chemistry and deals with the theory of the Ele- and magic inks; How to test flour; How to test soil; Tin (Granulated) (Sn) ments, Molecules and Atoms, etc. Chemical Nomeq- How to Make Chlorine Gas and smoke (German War d explains in simple language the deri- Zinc (Metal) (Zn) ature: This Gas) ; How to bleach cloth and flowers. How to pro- Zinc Carbonate (ZnCO3) vation of the chemical names of the Elements and to make chemical their compounds. There is a chapter on Laboratory duce Oxygen and Hydrogen; How Operations; Glass Working; First Aid; Fire Ex- colors; How to test Acids and Alkalies and hundreds The following apparata tinguishers; Experimenters' Aphorisms, etc. of interesting hints and formulas. are furnished: One Standard Washbottle Weight 10 shipped only.) One Alcohol Lamp The price is still $5.00. Shipping lbs. (Can be by Express One Conical Glass Measure One Erlenmeyer Flask One Glass Funnel One Delivery Tube Six Assorted Test -Tubes One Test -Tube Holder THE ELECTRO IMPORTING CO., Mfrs. Ten Sheets of Filter Paper One Glass Dropper 231 FULTON STREET NEW YORK CITY One Spoon Measure TRADE MARK Glass Tubing One book containing Trea- tise on Elementary "THE LIVIEST CATALOG IN AMERICA" Chemis- COMPANY try and 100 Chemical Ex- Our big, new ELECTRO IMPORTING periments to electrical cyclopedia No. 21 is waiting for 231 Fulton St., New York City be performed you. Positively the most complete Wireless and electrical with this outfit. I enclose herewit h 6 cents In stamps or coin, to catalog in print today. 176 Big Pages, 400 illustrations. cover postage, for which please send me your latest 300 instruments and apparatus, etc. Big "Treatise on ' Cyclopedia Catalog No. 21 as described. Wireless Telegraphy." 21 FREE coupons for our 160 -pago NAME FREE Wireless Course in 20 lessons. FREE Cyclopedia ADDRESS No. 21 measures 73E514". Weight 2,4 lb. Beautiful stiff STATE E.E. 1 -20 covers. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 865 LEARN WIRING Earn $50.00 to $75.00 a Week This Latest Edition of "STANDARD WIRING" Will Make You An Expert Wireman GENERATORS -How to install them, care for them and operate them; all their troubles and how to pre- vent and cure them ; all diagrams showing connections for compound, series and shunt wound machines. How to operate them in parallel or in series. How to protect them and wire them in accordance with the underwriters' requirements. MOTORS-How to install them, how to protect and operate them. The required amperes, volts or horse power when any two factors are known. How to take care of hot boxes, sparking commutators and other troubles. How to change the direction of rotation when desired. How to start and stop any kind of motor in any class of service. All diagrams of motor wiring. How to find the proper size of wire for any motor for POCKET SIZE LEATHER COVER direct current or for A. C. single, two or three -phase.

OUTSIDE WIRING -Pole line construction, line lighting fixtures. How and where to use flexible cord wires, service wires, roof structures, poles and their and where not to use it. How to install arc lamps and dimensions and weights, and how to erect and protect gas filled lamps and the fixtures and rules required. them and wires they carry. Insulators, guard arms, LIGHT AND ILLUMINATION -What is meant by guy anchors. Tree wiring, splicing, service and en- proper and efficient illumination, the latest data on trance wiring. How to install Lightning arresters. Mazda and gas filled lamps of every candle power and Transformers with diagrams and instructions. wattage. Direct, indirect and semi -indirect illumina- tion and where each should be used. Illumination re- INSIDE WIRING -When and where to use rubber quired for various classes of service from show window covered, slow burning and weatherproof wire. How lighting to public halls and from factories to small to find the proper size of wire to use for lamps, motors residences. or heating devices for any current, voltage and drop, either by formula or by the many tables that are given TABLES -Fifty -two tables giving every dimension, in this section of the book. How to wire for two -wire carrying capacity, resistance, weight and strength of or three -wire systems. Direct current, two -phase and every size of wire and cable of copper, steel and iron. three -phase with formulae and tables, with examples worked out for each system and in a simple manner All the necessary dimensions, capacities, weights, and that anyone can understand and use. How to run other data on conduits, fuses, insulators, lamps, sockets, wires on walls, ceilings, floors, through partitions and motor efficiencies, current per horse power of motors. walls and in concealed places, damp places and where Electrical units and their equivalents. Proper size of dangerous surroundings exist. When and where to wire for all classes of power, light and heating installa- install Switches, Cut -outs and Circuit Breakers and just tions. The proper symbols to use to indicate on plans how to do it. How to wire for high and low voltage just what is wanted from a motor to a small snap systems and the precautions to be taken. The proper switch with all necessary diagrams. way to install Knife and Snap Switches, Cabinets and Cut -out Boxes, Outlet, Junction and Switch Boxes, APPARATUS AND SUPPLIES-A classified list of Panel Boards, Wooden and Metal Raceways. How to the leading manufacturers of officially approved wires install complete interior conduit jobs either for rigid and wiring devices. Engines, generators, motors, metal, flexible metal or flexible non -metallic conduit. appliances, fixtures, and all supplies necessary for any Concealed knob and tube work or armored cable. How complete installation from a Central Station to a small and where to install and wire electric and combination cottage. The most complete and accurate Book on Wiring and Construction published 350 PAGES - LEATHER COVER - POCKET SIZE, $1.50 Sent Postpaid to Any Address on Receipt of Price by H. C. CUSHING, Jr., 8 West 40th St., New York Every Electrical Inspector in the United States will approve your work if done in accordance with the simple rules given in "Standard Wiring"

You benefit by mentioning the `Electrical Experimenter" when writing to advertisers. 866 ELECTRICAL EXPERIMENTER Januar:, 1920

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 6,200 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 and by steady application prepare yourself in a short time. You will be taught by practical electrical experts with actual apparatus, under actual conditions. The 2120011110101141,_ N. Y. E. S. gives a special Automobile Ignition Course as an Atr,,.. advanced training for Auto Mechanics, Garage Men and Car Owners. 111101101110 111iü' The course covers completely all Systems of Ignition, Starters, Lighting iw:M4ae;a1/.1#1 ji,ItRF. and other electrical equipment on automobiles, motor boats, airplanes, etc. Let us explain our complete courses to you in person. If you r Am o 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 sénd FREE and without obligation to me York your 64 -page New book. NAME Electrical School STREET CITY STATE 29 West 17th Street, New York 44011114 ,

ELECTRICAL EXPERIMENTER H.GERNSBACK - EDITO R H.W.SECOR -ASSOCIATE EDITOR IIIIIIIIIIIIIIIIIIIIIIIIIIÌIIIIIIIIf0 ,dIIIIlI11111111111111111111N11l

Vol. VII. Whole No. 81 January, 1920 No. 9 erne . Lbth miles Brooklyn, the 6 HE history of lighthouses is as old projector or searchlight, which can be seen "Within twenty of as navigation itself. Ever since the 100 miles at sea. The greatest range here- most brilliant lighthouse in America shines ancients ventured out of sight of tofore of any lighthouse has been 25 miles. every night. The Navesink Light at Sandy land in their triremes and their 'It was in the 18th century that the first Hook holds this foremost position, swing- sailing craft, there have been mar- attempts were made to use an optical sys- ing a beam of 11,000,000 candle -power out iners' beacons. From the beginning, naviga- tem with the light. In 1812, the United across the harbor entrance once every ten tion has been a twenty- four -hour -a -day in- States adopted a scheme consisting of a seconds. It is well worth a trip to this dustry and guiding beacons have been a crude copper reflector and a bull's -eye lens faithful mariners' guide to see the remark-

--;1''ePOT ÓFVERTNCáLBEÁMCB BE SEEM 10OMILES OR4TIMES OLDMA%.P,AHGE

___ .______' .....

AIRPLANES HAVE ACTUALLY SEEN VERTICAL BEAM 100 MILES AND FOUND THEIR BASE BY IT

HIGHEST LIGHT IN THE U. S. DUE TO CURVATURE OF EARTH CAPE MENDOCINO CAL. HIGHEST OLD TYPE LIGHTHOUSE WITH LOW -LYING CLODOS OR FOG 422 FT, ABOVE SEA LEVEL HAS RANGE OF DU T2SMILES VERTICAL BEM} VISIBLE SO MILES FOG OR CLOUDS OFTEN NULLIFY (OVER TOP OFCLOUDS OR FOG) IT ALTOGETHER VERTICAL BEAM VISIBLE 00 MILES Lt

Copyright by E. P. Co., 1920 the Old Horizontal Beams Which Were Often Not Visible at All In Foggy The Latest Idea in Lighthouses- Vertical Shafts of Light Instead of Is 25 Miles. Weather. Vertical Lighthouse Beams Have Been Seen 100 Mlles Away -the Maximum Range of the Old Style Beacon About necessity. Altho vague references to beacon in several of the important lighthouses. able Fresnel prism head. Two tons of op- lights are found in literature dating many But, in the terms of one of the old light- tical glass built in the form of a cylinder centuries B. C., the ,first lighthouse of which house reports of the time, it 'made a bad about six feet high are mounted so beauti- we have authentic record is the great light worse,' and hence was short -lived. fully that one can rotate the system with Pharos of Alexandria. This famous light It was succeeded, however, by better and the slight pressure of a finger. This heavy of the ancients, which was built about 258 better apparatus until in about 1852 the head floats in a container of mercury and B. C., was a huge tower of solid masonry Lighthouse Board adopted the Fresnel sys- thus rotates with practically no friction. on which a large bonfire was maintained tem of prisms and lenses, which has re- The two -ton head is revolved slowly all nightly. Even today one can see, not far mained unimproved for this service up to night long by the gradual dropping of a from London, the remains of an old mas- the present time. This system is now so small weight through the height of the onry beacon quite similar to the Egyptian universally employed for lighthouses that tower. Pharos." Thus spoke P. R. Bassett, re- one always thinks of a lighthouse as a "Let us look at the broader aspects of search engineer of the Sperry Gyroscope tower with one of these beautiful cages of the lighthouse problem and consider the Company, which concern has recently de- concentric glass rings and prisms mounted requisites and the limitations. In general, veloped a remarkable vertical lighthouse in the light -room at the top. (Continued on page 928) 867 868 ELECTRICAL EXPERIMENTER January, 1920

Top Right: Full Length View of Helicopter No. 1, Showing the Testing Installation of the Vital Features of the Machine. Lower Left: Showing the Temporary Installation of Two Electric Motors Each Capable of Developing a Maximum of 100 Horse - power. The Upper Gear Wheel of the Reducing Gear Is Seen Just Above the Box -Like Structure, Which Carries the Large Dial of the Platform Scales Used in Measuring the Lift or Thrust of the Propellers at Different Speeds and Power. The Motor Foundation Was Pivoted So That It Would Show Any Tendency of the Propellers to Turn the Whole Machine About Its Center. This Impulse Was Found to Be Practically Negligible, and the Entire Apparatus When Running at Maximum Trial Speed Could Be Rotated Freely to Right or Left by the Pressure of One's Hand. While Guys Were Attached to the Top of the Shafting to Steady the Machine, This Precaution Was Found Unnecessary, Because the Apparatus Stabilized Itself in a Pronounced Manner, the Faster the Screws Revolved. Lower Right: Details of the Propeller Blades, Guying and Shafting of Helicopter No. 1. Top Center Photo: Dr. Peter Cooper Hewitt in the Center. Thomas A. Edison, Who Is Inter- ested in the "Helicopter," at Dr. Hewitt's Left and One of Dr. Hewitt's Technical Assistants to His Right.

e " elicopter"9 rtical ir 1 ne By ROBERT Go 5KERRETT THE HELICOPTER has been an ture of the program. The cessation of hos- copter lagged. Now, however work is about aeronautical puzzle ever since in- tilities caused a tremendous slump in avia- to be resumed, and both Dr. Hewitt and ventive genius tackled the problem tion, and interest for the nonce in the heli- Prof. Crocker are positive in their asser- of producing a heavier -than- tions that the craft will do as well air flying machine. Mechanical aloft, as it has done within its hangar success of a sort has been realized at Ampere, New Jersey. from time to time by those variously The fundamental stumbling block engaged in this undertaking; but so heretofore has been a propeller capa- far as the records show no full -sized ble of translating into effective thrust, craft of this type, with one exception, or lift, a sufficient measure of the has been produced capable of lifting prime mover's developed power. None its designed full load. In short, they of them has in the past given, at useful have been unable to rise as they stood. working speeds, more than 10 pounds The one exception is the reason for of thrust per unit of horse- power- being of the present article. most of the aviation propellers fall In an effort to strengthen our coast considerably below this in perform- defense during the recent conflict, ance. The propellers evolved by Dr. Doctor Peter Cooper Hewitt, who has Hewitt and Prof. Crocker have yielded given the world the most economical more than 20 pounds of thrust per form of artificial light in his mercury horse -power ! These engineers have vapor lamp, and Professor Francis achieved this by breaking away from Bacon Crocker, long the head of the the generally accepted types of aero- Department of Electrical Engineering nautical screws both in the matters of of Columbia University, combined size, design, and the materials em- their talents to bring to a practical ployed. To be brief, they are adapta- head certain experiments with the tions of the aerofoil -the blades are helicopter initiated by Dr. Hewitt in relatively miniature airplane wings. 1906. They began their work in 1917, Without elaborating upon the physi- and a year ago brought their labors cal circumstances under which the to a brilliant climax after they had usual airplane propeller of relatively put Helicopter No. 1 thru a series of small diameter functions, it will suffice exhaustive tests. The armistice was to mention that it revolves at a speed declared just as the ground trials were An Early Forerunner of the Helicopter -a Steam Driven varying from 1,000 to 2,000 times a finished and flight was the next fea- Vertical Flier Proposed by Mr. de La Landelle in 1863. minute; it has a very large percentage January, 1920 ELECTRICAL EXPERIMENTER 869

a double of slip ; and its effectiveness is greatly re- Furthermore, due to the fact that the ter has assumed the desired angle, duced by the way in which it disturbs the screws neutralize one another, so far as set of vertical rudders, opposed to the line air well ahead of it. This latter motion they might tend to turn the engine plat- of advance, act against one another and cuts down proportionally the screw's hold form about its center, it is at once evident hold the machine in that plane of motion. upon the atmosphere and its capacity to that the helicopter will not spin about its The helicopter will be able to hover aloft, exert a propulsive effort. As the outer own axis when aloft. Also, it will, for and can be made to ascend or descend portions of a propeller's blade do most of this reason, be easily steered by the rud- vertically with the utmost deliberateness. the helpful work, it is evident that the hub ders to be provided for that purpose. Dr. With half of the engine power "dead" the and the massive inner sections of the blades Hewitt has designed a double reducing helicopter will return to earth at a safe are something of a handicap. Finally, ow- gear which will operate at a ratio of 23 speed. However, because of its high ratio ing to its moderate diameter, the ordinary to 1. By means of the wide use of op- of thrust per unit of power, it is feasible airplane screw has only a modest volume posing forces, and the employment of anti - to equip an aircraft of this kind with a of air to work upon. frictional bearings, this engineer- scientist reserve motor which can be put in gear In planning Helicopter No. 1, the first obtains a series of dynamic couples which at the will of the pilot or automatically aim was to obtain propeller blades having neutralize one another and thus insure upon the failure of any of the working high sustaining and propulsive factors, as balanced action. engines. the entire burden of lift and horizontal In all of its essentials, Helicopter No. 1 Professor Crocker has thus summarized movement was to depend upon the screws. is a practical man -carrying machine, and the advantages of the present type of flying These were mounted upon concentric, tubu- can be made ready for flight by substituting machine: "The helicopter will start from It was two airplane engines in place of the testing any moderate space such as a roof or or- lar shafts, revolving oppositely. to not enough to use aerofoil blades; dinary street, and come back to have land on the same spot. It is in- it was quite as necessary dive, recourse to propellers of large herently stable and cannot diameter, driven at comparatively the support being all above and the weight below ; so that special low angular velocities, which would it act upon a large mass of air with- skill is not required to operate out previously setting up discount- at high or low speeds to prevent ing perturbations. To this end, it from getting out of control. the propellers of Helicop- The helicopter is substantially each of being constructed thru- ter No. 1 has a diameter of 51 feet, fireproof, of revolution is out of metal. To build it, no labor and the speed difficult to about 100 turns a minute. or materials that are The blades are attached to tubu- obtain are needed. The craft can lar steel arms, and placed where the be constructed in an ordinary make most ef- machine shop, and can be assem- periferal speed will or repaired fective their length of 15 feet and bled, disassembled, feet. The with the skill and facilities corn- their breadth of 2/ The heli- blades consist of a succession of mercially available. transverse partitions or frames of copter is far less noisy than the aluminum over which is laid, top airplane and, because of its gen- of eral design and arrangement, less and bottom, a single sheathing sky." the same metal. To prevent "chat- conspicuous when up in the tering" the blades are attached to As the editors see it this re- the supporting arms forward of the markable development in flying center of pressure. Therefore, the machines certainly looks like a blades are, in effect, drawn instead long step in advance, if all of the of being pushed thru the air. This many predicted qualities inherent arrangement gives the blades a cer- in its design are fulfilled in actual tain measure of automatic adjust- flight. Especially in war -time will ment of pitch when meeting with the marked advantages of this varying stresses and changing an- type of aircraft be apparent, for gles of travel on the part of the its visibility will be far less than machine. that of the present airplane, which The vital features of Helicopter has wings of considerable area. No. 1, as assembled for testing, Besides, the small wings or re- weighed something less than 2,300 revolving screws of the Helicop- pounds. When the screws were ter will prove a difficult target for turned at the rate of 70 revolutions the enemy gunners, whether aloft a minute -their two electric mo- or on land. The cab of the Heli- tors then developing 126.5 horse- copter can be armored so as to power -the total effective lift readily withstand ordinary bullets amounted to 2,550 pounds, i. e., and shell fragments. And just 202 pounds of lift per horse -power! imagine the great superiority of Electric motors were used in place 1. Inner Concentric Shaft Which Rotates Upper Propeller, 9 an aerial observing station that of aviation engines because they 2. Outer Concentric Shaft Which Rotates the Lower Pro can "hover" about, in one spot if it possible to carry on the peller, 10. need be, in order to gain an ac- made 3. Permanent Tubular Sleeve Which Takes the Weight of tests progressively, from the low- the Machine and Alternately Bears the Lift and Compression curate sight on enemy artillery est speeds upward, and to read off Loads When the Craft Is Flying or at Rest. and other activities. at the electric meters the actual 4. Upper Wheel of Reducing Gear. We have now considered some at any moment. 5. Lower Wheel of Reducing Gear. The Geared Pinions on of the advantages of the Helicop- power consumed the Engine Shafts Are Introduced Between These Wheels and The driving apparatus between the Drive Them Equally. The Shaft of the Lower Propeller Is ter, but it would seem to the edi- motors and the shafts consists of Secured to the Upper Wheel and the Shaft of the Upper Pro- tors that there are also some dis- an ingenious reducing gear by peller Is Attached to the Lower Gear. advantages. For instance, owing which it is feasible to step down 6. Engine Foundation Structure. to the small sustaining surface of 1,400 7, 7. Aviation Motors. the screws, which act virtually as the prime movers' speed from Fuselage. 100 a minute. This 8. wings also, what will happen if ac- to revolutions 11 and 12. Rudders That Can Be Swung Both Horizontally makes it practicable to employ the and Tipped to the Right or Left from the Vertical. By Tip - cidentally or in battle, the engines high -speed aviation engine and yet ping Them Oppositely, the Down Draft from the Propellers happen to fail ? It would seem to obtain the desired low rotary Tends to Rotate the Fuselage So That the Craft Will Swing to that the airship would obey the Port or Starboard. By Tipping No. 11 So That the Rudder movement of the propellers. Face Is Vertical instead of Horizontal the Machine Is In- law of gravity and dart earthward The reducing gear was developed clined by the Head and Will Then Advance Horizontally in at a rapid rate. Airplanes can that Direction. Similarly So Inclining No. 12 will Cause the down safely if by Dr. Hewitt, and, while possess- Helicopter to Travel Rearward. volplane the engine ing a measure of flexibility to meet After the Craft Is Started Horizontally at Any Angle of Ad- stops, as their superior wing sur- the variable stresses of mechanical vance, the Rudders 13 and 14 Are Set Oppositely, Thus Form- face allows of their doing so ; flight, is, nevertheless, positive in ing a Dynamic Couple Which Tends to Hold the Machine but perhaps the inventors of the the contacts between the pinions of Inclined and Upon the Desired Line of Travel. Helicopter here shown have cir- 15 16. Rudder Yokes. the engine shafts and the two and cumnavigated this problem in a geared wheels to which the upper manner which they have kept to and the lower tubular propeller shafts are, electric motors. It is only necessary to themselves so far. respectively, secured. Revolving oppositely, tip the machine a matter of about five de- Those interested in trying out the merits the propellers exert a very notable stabil- grees toward the bow or toward the stern, of the Helicopter flying machine will find a izing moment ; and so marked is this effect to propel it at high speed in either of these most interesting article on a successful fly- that it was unnecessary to steady the ma- directions. This tipping action is effected ing model of this type, by Mr. William J. chine by guys during the ground trials! by suitable rudders ; and when the helicop- Beach, in another part of this journal.

T 870 ELECTRICAL EXPERIMENTER January, 1920 e Eaarffc e 113cofilD:le?

WOODHOUSE, the well - developed by the dynamos ; and these losses known What An Eyafinent# ENRY aviation expert, recently are more than compensated for in apply- gave out a report that there had AIlppIlane ing the electrical drive to the airship, by I I been plans disclosed in Chicago neer Oays virtue of the much smoother operating for a radically new type of flying control and driving qualities. One thing craft, to be propelled by electricity entirely, is certain -that with this that it is arrangement of and therefore to be of such great power a wonder they show up as well gasoline -electric propulsion we know it will and efficiency as to be able to make flight as they do. work !- providing we build our electric ma- around the world. "I do not mean that they are altogether chinery unsatisfactory, sufficiently light, as Dr. Christmas This wonderful new flying machine, he but I do say that they can has pointed out, so as not to over-burden be improved upon by substituting a com- the flying said, was designed for propulsion thru the mon electric craft with useless dead -weight. air by motor. The power -plant here shown, comprises electric motors driving the propeller "The electric motor is blades, with a total horsepower of 6,000. compact. While 6,000 horsepower of electric motors driv- the present day motors are heavier and ing the four The airplane is also credited with being bulkier per horsepower screws, or each motor pro- 100 than most aviation duces 1,500 horsepower. The motors may capable of carrying from 75 to pas- engines, this is because sengers, and the wings are to have a spread aviation engines be operated in pairs in case one generat- have been refined for the particular service ing set should fail, and of 240 feet, while the airship itself is 180 on airplanes and therefore the two feet in length. The appearance of this new electric motors have not. inside or else the two outside screws can Now if our electrical geniuses put their be used. flying craft is shown in the accompanying heads down to illustration. the job of developing a fine The two dynamos develop 3,000 H.P. aviation motor, they will doubtless come each and are driven by two 3,200 H.P. gaso- WHAT DR. WILLIAM WHITNEY CHRISTMAS within the same limits that the gas engine line engines. The pilot in his cabin, atop THINKS OF THE ELECTRIC AIRPLANE. men have attained.' the main body of the aircraft, has full con- "The problem of supplying the electric trol of the speed of the propelling screws Before going further, it would be well energy to the motor on electrically- driven at all times. Where the propellers can be to listen to what a leading aviation expert, airplanes is, as we might surmise, some so accurately and easily controlled, as in Dr. William Whitney Christmas of New problem! However, it is not insolvable, the case with the electric drive, the ease York, has to say with respect to electri- and there are three obvious ways to be of handling of the airship is greatly en- cally- driven airplanes. Dr. Christmas is suggested. One -to carry storage batter- hanced, as for instance by speeding up the the inventor of the famous "Christmas ies; two-to transfer electrical energy by screws on one side, and reducing their Bullet," whose cantilever supporting wings wire or wireless, i.e., as by means of a de- speed on the other side, etc., especially in are flexible like a bird's, but not to the pending trolley cable between the airplane bad weather. With electrified airships there same extent. The "Christmas Bullet" is and a contact or third rail, over the contact comes many other niceties for long distance the fastest plane in the world and has made rails of which would run a contact shoe journeys, such as electric cooking, electric 200 miles an hour on official test, when at the lower end of the cable; and the wire- heating, electricity for operating a power- fitted with a liberty motor. Recent unof- less transmission of energy, referring to ful radio set, electric lights, and an elec- ficial reports from France, mention a new the ideas of Dr. Nikola Tesla, of course trical gyroscopic compass. record for an airplane flight of 226 miles not developed yet to the stage of practic- As will be noted from the illustration, per hour. Dr. Christmas has been con- ability; and third -a gasoline- electric air- the radio antenna in this machine follows nected with aviation matters from the days plane in which great constancy of power the latest departure in this direction, and of Professor Langley, and his views upon and beautiful control of driving screws are the wires constituting the antenna are the subject 'of airplanes are therefore of obtainable. In this scheme the gasoline placed inside the wings. interest to us. engines drive dynamos which generate elec- Objection might be raised on this point tric current, and this current is then Dr. Christmas said : "In suggesting that con- that there is considerable danger of fires airplanes be driven by electricity, I realize trolled as desired by the pilot, and fed to owing to electric discharges from the an- that I am making myself open to severe one or more electrically -driven motors to tenna wires, but it might be said that the condemnation by many well informed which the screws or propellers are at- latest idea in building such machines is to gentlemen who say that it cannot be done. tached." cover the wings with sheet aluminum or Nevertheless, I am of the opinion that the THE GASOLINE- ELECTRIC AIRPLANE TO aluminum alloy sheeting, in the same man- ultimate craft of the air will be electrically THE FORE. ner as some of the German and other for- driven. eign planes have been successfully built. As the accompanying illustration shows, As will be seen, there is room for a "It is not my part to say how this is go- the layout and arrangement of the electric ing to be accomplished, but to argue from limited amount of baggage on such an air- propelling mechanism on the newly pro- plane, and for night trips, sleeping quar- the present failings of the aviation gas en- posed airplane described by Mr. Wood- gine to the conveniences of electric motors. ters may be provided on the order of the house, is along well -known and thoroly well -known Pullman car accommodations - "As is well known, an airplane depends tried engineering lines and corresponds to that is, by converting the seats into berths. upon its motor to stay in the air and the the electric drive on our newest battleships. Powerful electric searchlights are avail- very delicate adjustments required on com- There is not a very great loss in con- able for flying at night, and especially for mon aviation motors make them not en- verting the mechanical energy developed in landing purposes, while port and starboard tirely reliable. There are so many parts the gasoline engines (of which there are lights or markers are fitted on all such that can wear out or get out of adjustment, two in this case) into electrical energy as planes at the present time. Gemir Convepca3tIlOo n One MIlle Away It is a common knowledge, especially ried on by the Allied troops, it was pos- tered his trenches, underground dugouts among men of the U. S. Signal Corps who sible by the use of the high power ten - and wine cellars, it is a matter of record served with the A. E. F., that by means of step amplifiers, both French and American that the Allied troops, in many instances. the wonderful 6, 8 and 10 stage audion am- type, to overhear telephone conversation and particularly toward the close of the plifiers, available in the present war, and and also telegraphic signals whenever the war, found whole sections of German tele- by placing a parallel loop of wire over a Germans happened to communicate over phone instruments over a considerable area few hundred feet near the front lines, wires, at a distance of one mile behind the near the front lines entirely sealed with that enemy conversations could be easily front line trenches. Interrogated at this red labels marked "Verboten," and, fur- and accurately intercepted and amplified. point, the expert explained that not such thermore, some of the captives stated that As we have just said, this phenomena is a long wire loop was necessary their troops had been ordered not to use as might be the telephone at more or less well known, but it is not gen- supposed, but that a wire about 250 feet all under any considera- erally known, we believe, that, as recently tion, even where the wires were laid in long, placed parallel to the German iron pipes. Many other valuable uses were pointed out by a U. S. radio expert who trenches, was all that was necessary, and made of these eight and ten -step vacuum invented the amplifying radio buzzer sys- just to show that the "Yanks" had the amplifiers, some of which will be described tem used in trench and field warfare car- "Boche" on the run long before he en- in future articles. January, 1920 ELECTRICAL EXPERIMENTER 87

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U W 872 ELECTRICAL EXPERIMENTER January, 1920 hmg, C FOTC Ccaull.a IR OLIVER LODGE, the eminent There are some scientists who raise the the atom, that English scientist, we depend for the different declared recently question as to whether or not the electron substances or elements which we have to- that the first utilization of basic is really the ultimate sub -division of matter. day, such as iron, tin, copper, atomic properties of matter, had first gold, silver, Some scientists think the electron may in etc. Every ounce of matter that we know been utilized by man in wireless turn be composed of a series of small elec- of today, including telephony. This refers our very bodies, is to the remarkable tric charges, and that these charges may composed of millions of billions of these ' electronic action occurring in Audion bulbs. represent the ultimate particles of matter. ever -whirling electrons, so our scientists He added, that if the atomic energy of one Fig. 4 show., the whole electron family. tell us. ounce of matter could be utilized in a prac- First we havçthe molecule, which is com- tical everyday sense by man, it would be posed of DIFFERENCE BETWEEN BREAD AND IRON atoms, -then the atom, which is ONE sufficient to raise all the German ships sunk composed of electrons-and finally the elec- OF ATOMIC STRUCTURE. in Scapa Flow and pile them on top of tron, which may be easily composed of Thus, we see that the difference between the Scottish mountains. In conclusion he ultimate ether particles -which latter are a piece of bread and a piece of iron-is stated that it was his hope that the human thought by some physical investigators to that one has a different electronic structure race would not discover how to use this than the other. Aluminum, for example, has a vast store of energy until it had brains ,,,,,,..,eeI,,,FF11111111,11,1,1,1,1111.11111111111111111111111111111111111111111111111111111111111,u111111,11111111.1, different number of electrons whirl- enough to apply it properly, because if the ing around its atomic nuclei than does gold discovery were made before its time and or iron. It has been intimated by some of by the wrong people, this planet would be our ablest scientists that the dream of the unsafe to live on. For "February" Alchemists of old would surely come to pass, once we master the key to the RADIUM WATCH DIAL A VEST -POCKET atomic POWER -PLANT. structure. For if we can apply, let us say, How I Discovered Radioactivity - a powerful electric charge to a certain sub- What is this atomic force and have we Feature stance so as to alter its any means of seeing it at work today? illustrated article specially electronic and written by Prof. Becquerel. atomic formation, then we can turn lead or Thanks to Radium and Radio- activity, we iron have into gold, but we have no such con- a means of demonstrating some of the The Giant Canadian Reflector- trol as yet over the electron family wonderful effects of sub -atomic activity on circle. Second Paper on Large Telescopes Thus we cannot cause them to combine in a small scale. If you own a radium dialed and any desired pattern, altho watch with luminous figures and hands, How They Work, by Prof. Floyd we are beginning L. Darrow: to learn what some of these patterns are, then you are the possessor of a vast power at any rate. plant of no mean proportions. There is When Weight is Zero. By H. As Professor sufficient radium on your watch dial to haul Millikan has shown, as well Gernsback. as other investigators, there is apparently you train homeward, if it could be proper- a ly applied. As the matter stands, the inno- The Audion as vast amount of space between the elec- a Scientific Magi- trons in an atom and experiments have cent- looking radium dial does not seem to cian -What it has done and is doing. been possess made which have demonstrated this phe- any extraordinary amount of con- Prepared in collaboration with Dr. nomenon to very centrated energy, but this is only appar- a remarkable degree. Free Lee de Forest. electrons have been shot thru an atom ently the case, and not actually so; for the without reason that while the amount of activity The Dark Searchlight touching any of the other electrons - Taking in that atom, or without dislodging any of manifested by the radium paint on the dial "Movies" by invisible light rays, by them, is small, this effect will keep and past on over a considerable dis- up for 2,500 Lewis Yeager, its inventor. tance before coming to rest. years, provided the zinc sulfid, with which Fig. the radium is mixed New Experimental 5 illustrates Sir Oliver Lodge's pre- so as to produce a Chemistry diction of what might occur glow, held out that long. The zinc sulfid Series. No. 1, Alcohol if we under-I in -To be con- stood how to produce atomic disintegra- most cases gives out in about eight to ten ducted by Prof. Floyd L. Darrow. tion and realize years. See Fig. 1. the tremendous, almost "in- Radium-the Wonder- Substance- conceivable power locked up in the atom- One of the accompanying illustrations, that is, could Fig. 2, shows a sectional view of a very in- Some unusual and simple experi- we raise all the German ships that were sunk in the Scapa Flow atop the teresting radio -active instrument known as ments .illustrated and interestingly Scottish mountains. the "Crookes Spinthariscope." This instru- told, by Harold F. Richards, A.M. ment which is a simple and inexpensive de- It is interesting to learn of some other vice, demonstrates in a most beautiful man- The New Theory of Electrical remarkable results that could be accom- ner the marvelous activity of radium or Mass, by Rogers D. Rusk, M.A. plished by atomic disintegration. As Soddy shows, radium gives off heat any radio -active salts. Building Model Airplane Motor of at the rate of It comprises an eye lens -piece, as shown, 133 gram calories per hour, or .in the 2,500 the Rotary Comprest Air Type, by years of its life ,(half period of decay) which can be adjusted to different focuses, W. J. Beach,,M.E. and in the bottom of the tube there is placed it will yield the stupendous :total of 2,900,- 000,000 , a zinc sulfid Just A New Commutator -less C. gram calories per gram of pure screen. in front of this A. gnd radium. The screen there is placed a tiny speck of some D. C. Machine, by Richard A. Engler. calculation data on the steam radio -active substance. The needle holding locomotive were kindly supplied by Mr. H. this substance is usually mounted on an Radiotelephony and the Airplane, S. Vincent, of the Engineering Department adjustment nut. This spinthariscope, when with diagrams, by William C. Mundt. of the American Locomotive Co. An inter- esting computation "slows that five viewed thru the lens opening in the dark, Audion Hook -ups -a page of them ounces presents a most wonderful spectacle, as of this precious stuff, which you can hold -Centralized battery connections for in your hand, would propel a standard pas- hundreds of the atomic particles, thrown grid and filament, and hosts of others. off continuously from the radio -active sub- senger train of 10 Pullman cars from New York to Chicago, a distance of 908 miles stance, bombard the zinc sulfid screen ; each by railroad. How many tons of coal do you spot at which a particle strikes the screen ,111111111111,11M111 1,Mg...1111111111111111111111111111/111111111111111111,.111tt.,...111. lighting up, until the whole interior of the think it takes to drive such a. train over a spinthariscope resembles a veritable fire- 900-mile, 22 -hour .journey? It requires 60 works display. be without weight. In other words, these tons of the best anthracite coal to make one ulti-particles would merely be ether whorls. trip from New York to Chicago or vice THE STRUCTURE OF THE ATOM. Now we are coming to the point that versa. Such a train averages 41 miles per The modern idea of the structure of an Sir Oliver Lodge had in mind when he hour and the steam passenger engine used atom as well as the family tree of the atom made the statement cited in the forepart for the trip develops an aberage .of 1,600 and molecule are shown in Figs. 3 and 4. of this article. What he meant when he horse -power. The engine is rated at 2,200 Referring to Fig. 3 we see that the atom, intimated what tremendous amount of en- horse -power. which was the smallest known sub -division ergy 'would accrue to mankind if we could FIVE OUNCES RADIUM WOULD DRIVE .of matter a few years ago, is composed of only unlock the secret of the atomic struc- TRAIN 900 MILES. a positive electric charge or nucleus, around ture, was this : That instead of having" to which there are constantly rotating at tre- wait thousands, or hundreds of thousands The manner of computing the amount of mendous velocity, a certain number of elec- of years, for atomic radium required to duplicate the work of a structures to form of 60 trons or negative electric charges. This their .1wn accord, that we should be able -ton coal pile, measuring 67 feet high, idea of the atomic structure is believed in to re- arrange the formation of the elec- with a base 10 by 10 feet, as shown at Fig. by practically all of the leading scientists of trons in the atom. For it is upon the num- 6, is based on the assumption that each today, 'including such men as Millikan. ber of electrons and their arrangement in - (Continued on page 934)- January, 1920 ELECTRICAL EXPERIMENTER 873

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EmIny has blazed the trail in operarting conditions ; this was often the motor, which motor is connected directly many of the world's greatest en- actual experience of the C. M. & St. Paul on the same shaft with two direct current, gineering projects and accomplish- Railway. It has happened many times 3,000 volt generators. The two D. C. gene- A ments, and it has remained for one since this system has been operating with rators are connected in series and deliver of the great western railways of electric locomotives, that one of these 3,000 volts D. C. to the over -head trolley the United States to electrify the longest "electric steeds of the rail" has been sent wires from which the electric giants of the stretch of trunk line in the world, and out to haul in a disabled and frozen up rail derive their power ; not thru the ordi- which within a short time will extend over steam engine. nary trolley pole, but by means of a very a distance of about 850 miles. This route In the accompanying illustration several elaborate trolley contactor known as the extends over some of the steepest ranges interesting comparisons, of steam and pantagraph trolley. The advantage of this of our western mountains. The enterpris- electrified railroad systems, are vividly de- trolley contactor is that on curves and also ing railroad which has had the foresight picted. The two locomotives, one electric, on high speeds for straight runs, there is and courage to attempt such a gigantic ann the other steam -driven, here illustrated, only a slight probability of the trolley electrification scheme as this, is the Chicago, tell the story of the wonderful advance in losing contact with the wire. The ordinary Milwaukee and 'St. Paul Railway, whose railroading over the vast stretches of our city or suburban trolleys use but 550 volts tracks pass thru the thriving cities of St. western plains and mountains from the D. C. Paul, Minneapolis, Butte, and Spokane. The year 1848, when the first steam engine, ELECTRIC EQUIPMENT. section of this railroad running between "Bob Ellis ", here shown, proudly hauled the Harlowton, Montana, and Avery, Idaho, first train of cars over Wisconsin rails, up Under normal conditions, forty -two 440 miles trunk line distance, and passing to the present day, when the gigantic elec- powerful electrical locomotives are re- over the great Continental Divide, has been tric locomotive here shown, swings up and quired to haul freight and passenger trains in electrical operation for some time. Work over the precipitous mountain paths and on over the electrified mountain districts of has been under way for several years on the to the coast, 850 miles thru America's most the Chicago, Milwaukee & St. Paul Rail- electrification of the main trunk lines pass- gorgeous scenery. way. These locomotives each cost approxi- ing over the Cascade Mountains in Wash- mately $112,000; they weigh 284 tons each ington, between The electric power for operating this and will haul 3,200 -ton loads, trailing up a Othello and Puget Sound electrified railroad system, is derived from to 1 per cent. grade at an average speed of Seattle, a distance of 211 miles. Electric vast water-power developments, which have current has recently been turned on the 110 sixteen miles an hour. Similar electric mile stretch been brought to their present stage of ef- locomotives, geared for greater speed, will of this system, extending from ficiency by the Montana Power Company. Othello to Cle Elum, as shown in the ac- haul 800 -ton passenger trains over the same companying The electrical power supply utilized in stretch at a speed of sixty miles per hour. illustration. operating the 440 miles of electrified trunk By the first part of the year 1920, it is To appreciate the immense tractive power line, between Harlowton and Avery, and of these electrical "Goliaths" one should expected to "open up" the electrified section the 160 miles of electrified spur and yard of the road from Cle Elum to Seattle, or know that the wood -burning locomotive of trackage in Montana, is obtained from the fifty years ago weighed twenty about 130 -miles. This will then give a hydro-electric power plants of the Montana tons and had a tractive of only 5,000 pounds ! completely electrified trunk line for a dis- Power Co., whose main plant is located at power tance of about 680 miles. As becomes evi- The present -day big Mallet steam locomo- Great Falls, Montana. The electric power tive has a tractive power of 76,200 dent, this leaves a gap of non -electrified or for operating trains over the Cascade dis- pounds steam operated trunk line, extending from and the electrical locomotive, weighing 284 trict will be obtained from hydro -electric tons, has a tractive power of 85,000. Avery to Othello, approximately 220 miles, developments at Long Lake, Snoqualmie which for the present will be operated with pounds. These electrical locomotives are Falls and possibly Priest Rapids on the 112 feet, 8 inches long, and are driven steam driven locomotives. However, a Columbia River. The electric current from by grand scheme of electrification has been separate motors, twin geared to each of the water -power generating stations is de- eight pairs of driving wheels. The cab ex- mapt out by the engineers of the C. M. & livered in the form of 100,000 volt alternat- St. P. system, for the complete electrifica- tends nearly the whole length of the loco- ing current. With this high potential the motive. tion of the entire trunk line between Har- tremendous losses are brought to a very lowton, Montana, and the Pacific coast, low minimum, and electric power may be REGENERATIVE BRAKING. that is, Seattle and Tacoma, which will give transmitted for a great distance, even 200 a Regenerative braking applies to a method total electrified route of about 900 miles; miles or more, when necessary. The elec- used on down grades, by which the train, this means one way direct trunk line mile- tric power for operating the mountain dis- instead of consuming electricity, actually age and does not include auxiliary trackage trict for example, is delivered at 100,000 produces it while traveling onward, and such as spurs, switches, yard tracks, etc., volts potential over transmission wires by which, at the same time, the speed of which would make a total of about 1000 strung along the route on steel towers and miles the train is kept under perfect control. of electrified track. When the com- is distributed along the way to 14 sub-sta- This is the first use ever made of direct plete electrification is effected within a year tions. The purpose of these sub -stations current regenerative braking, and the fol- or two, when railroad matters have become is to pass the 100,000 volt ultra -high poten- lowing from an authority on the subject more stabilized than they are at present, tial alternating current into transformers explains its functions: due to the government operation of rail- and thence into rotary transformers, which "Electric motors are reversible in their roads which has markedly curtailed the gi- convert it to a much lower tension direct function, namely ; while they absorb elec- gantic improvements which would have current, or one having a potential of but trical energy and give out mechanical taken place otherwise, this system will have 3,000 volts ; as but 1,800 to 2,000 volts is energy going up grades, they can reverse succeeded in electrifying within 200 miles, required to kill a man in the electric chair, this operation and absorb the mechanical one -half of the entire mileage of the St. it may readily be judged what a tremendous energy given the down Paul- Seattle line. train grade by potential 100,000 volts really is ! The sub- gravity, and transfer it into electrical It would be considered a wonderful feat stations thus perform two important func- energy. Thus the electric locomotive pro- of electric railway engineering, even if this tions -they transform the 100,000 volt cur- vides a perfect braking system, which is in- great length of trackage had been electri- rent down to one of 3,000 volts, which can dependent and separate from the air fied or was about to be electrified, over a be more safely used in operating the motors brakes, which are used only in emergency stretch of level country, but one glance at on the locomotive, and besides-they and for stopping trains. Electric energy so the profile view on the opposite page show- change the alternating current to a direct generated can be turned into the trolley ing the severe grades met with in climbing or a continuous one. wire to assist other trains and reduce the the stiff mountain ranges, will give some The alternating current pulsates or rather amount of purchased electric current." slight idea of the titanic task encountered alternates from positive to negative about In actual operation, at the crest of the in the "engineering" of this vast 20th cen- 120 times per second, while the direct or grade, the helper locomotive is brought to tury development. continuous current passes in the same di- the front of the train and coupled with Previously steam locomotives, the largest rection continuously, i.e., one wire is posi- the forward locomotive, both being ever built, puffed and snorted painfully tive and the other negative all the time, operated as one. The train is then con- over these mountain trails. In the winter while with alternating current, such as used trolled on the down grade by regenerative time, when snow and ice descended in the in the main 100,000 volt transmission lines, braking. passes to depths of 15 to 20 feet, and the the wires become charged positive and This system of braking provides maxi- mercury in the thermometer slipt out of negative, alternately, 120 times per second. mum safety, eliminates wheel, brake -shoe sight, the only thing the steam engines Motor -generators are used in each sub- and track wear and overheating; insures could do was to stand fast on the track and station, the stept-down alternating current uniform speed on down grades, and re- freeze up, so severe were the winter -time from the transformers operating an A. C. (Continued on page 931) January, 1920 ELECTRICAL EXPERIMENTER 875 876 ELECTRICAL EXPERIMENTER January, 1920 Mmgnefic S4omEn.s Y LEHR/LEY IL Professor of Physics, Washington University, St. Louis, Mo.

How Sun Spots,9 !A Ilnfl Wind mama Cfl® ld Shmd®ws Affect Emirt ns Magnetic Force and is a slow progres- sive change with lapse of time. The diurnal change is one that has a daily cycle or period and is repeated day af- ter day. It was discov- WIND,RAIN,ANDCLOUD ered in 1722 and is no SHADOWS MAY CAUSE doubt related to the "MAGNETIC STORMS" - ionizing action of (CHANGES IN EARTHS sun- MAGNETIC FIELD) light upon the atmos- phere. T h e annual change is likewise a re- curring change, but is repeated every year. It is a small variation OBSERVERS AND and is without doubt "MAGNETIC STORM" due RECORDING APPARATUS to forces situated IN PIT outside the earth. The present paper deals primarily with t h e Irregular Fluc- tuation s, commonly termed "Magnetic Storms." These are small, irregular fluctuations which may be especially marked for a duration of a few seconds, a few hours, or even for several days.

MAGNETIC STORMS CAUSED BY WIND, RAIN, CLOUD SHADOWS AND SUN SPOTS. Just as a rain storm may be a purely local affair or may cover half a continent, so may a magnetic Top Photo: Typical record of a "mag- storm Photograph publlsht by the United States Coast and Geodetic Survey. Shows netic storm" or variation In the earth's be purely local in ori- part of the equipment at the U. S. Magnetic Observatory, Baldwin, Kansas. magnetic field. Fig. 2. gin or world wide in Instrument at left registers the deviations In "direction" of a compass needle. Photo below: Photograph of Prof. Instrument at center registers the variations in "strength" of the pull upon a Nipher's magnetic, research station lo- scope. In November, compass needle. The Instrument at the right records photographically on the cated on the lake shore at the north end 1882, sensitive drum -paper the position of the beams of light reflected from the mirrors cf Lake Huron. 1914. The weighted near the period attached to the suspended magnets of the first mentioned instruments. frame -work holds auxiliary magnets; of maximum sun spots, lasing around suspended magnet show at center. a magnetic storm oc- curred at the same mo- ment over the entire earth. Such disturb- MAN is so constituted that his or- ered an open one. However, we are on ances are usually accompanied by auroral ganism is sensitive to certain sure ground when we state that the human (Continued on page 920) types of energy transmission and organism is not directly insensitive to others. Our bodies aware of the magnetic are able to detect changes in field of the earth, and temperature, changes in wind velocity, without the aid of special changes in humidity, changes in intensity apparatus would be as un- of a light source, and our thermometers, aware of it as if it were anemometers, hygrometers and photome- absolutely non - existent. ters are devised to measure these things. But the compass needle Our bodies are insensitive to the slow and furnishes irrefutable evi- continuous changes in atmospheric pressure dence of the presence of as indicated by our barometers and baro- this mysterious ether phe- graphs, tho we do respond to quick changes nomenon. in pressure such as we experience in the At any chosen geograph- rapid ascent or descent of elevators in sky- ical location close observa- scrapers. But there are cases where only tion shows that the com- our inanimate instruments are able to de- pass needle undergoes con- tect the presence of some physical agents tinuous fluctuations corre- and variations therein. sponding to changes in di- One of the most notable cases is that of rection and strength of the magnetic field, -a man can thrust his the earth's magnetic field. hand into the airgap of a powerful electro- These changes may be magnet and experience no sensation what- clast as (I) Regular Fluc- ever. Of course when the body, which is tuations, and (II) Irregu- an electrical conductor, is placed in a vary- lar Fluctuations. The first - ing magnetic field there must be induced named may be grouped electrical currents set up in the tissues. under three principal sub- Some experimenters have claimed to have heads: (a) Secular, (b) detected the effects of these currents as set Diurnal, and (c) Annual. Electrical Apparatus Devised by the Writer of the Present up by very powerful alternating magnetic The secular change has Article for Recording the Effect of "Magnetic Storms" or Fluctuations in the Earth's Magnetic Field. See Also Fig. 1 -A fields, but the question may still be consid- been known since 1634 for Connections. January, 1920 ELECTRICAL EXPERIMENTER 8 7 7

The Above Views Show the Large Men's Swimming Pool at the Hotel Pennsylvania, New York City. At the Left, and Also In the Center at the Right -Hand View, May be Seen the Tile- Covered Water Purifying Apparatus, the Ultra -Violet Ray Tubes of Which Sterilize All the Water in the Swimming Tank Continuously. Electrically Operated Ultra- Violet Ray Tubes Accomplish This Result. 5wIlmnain Pool Y IrecerrIlc y JOSEPH No KRAUS OF the thousands of people who in fact all germs and fungi are completely frequent swimming pools every H®w Una-a-Vn®Ile4 destroyed by their action. These lamps year, how many realize the fact Rays Stei'flIlilze Svyr Il m- were developed by Peter Cooper Hewitt in that such bodies of water, both part ; that is, he developed the mercury indoors and outdoors, are pol- S(TLIf iiltì ®®Il WateIt vapor arc and De Mare has first used it for luted with germs and bacteria of all kinds? water sterilization. This hotel uses 220 A bacteriologist can at any time secure of all germs, fungi, and other poisons. volts direct current for the operation of water from such a pool and upon making This sterilizer consists essentially of a these lamps. a germ culture, will find it filled with the container thru which water is past, this Ultra violet rays, altho invisible and in- bacteria of various diseases such as influ- apparatus being connected with the in- tangible, are easily produced in very large enza, typhoid, enteritis, diptheria, Asiatic take and exhaust water pipes, and a spe- quantities by quartz glass mercury vapor cholera, peritonitis, tetanus, etc., and sel- cial type of electric lamp using 220 volts, lamps. When started, the lamp is tilted, dom do people believe that they have ob- which generates powerful ultra violet rays. which breaks the mercury bridge and the tained the disease from polluted waters, These rays are generated and radiated arc is struck, whereupon the mercury is preferring to accuse any other source than thru a quartz tube surrounding a mercury vaporized and the current passes thru the hot to think of the possibility of "catching vapor arc, as shown in the accompanying vapor, thus maintaining the arc. Not only something" from an innocent- looking illustration. is this method economy in itself, but it opens swimming pool. Strange as it may seem, ultra violet rays up a new branch of swimming pool water One hotel management in New York has have the peculiar property of a complete sterilization, inasmuch as by using proper shown foresight enough to know that such bactericidal agent, and pathogenic germs, filtering and circulating apparatus very is actually the good and ,sani- case, and that tary water can ULTRA VIOLET RAY LAMP be supplied in- disease germs PpbITION OF METALLIC MERCURY(LAMP IN NORMAL OPERATION) ANODE SEAL definitely, as at do breed and CATHODE LEAD ANODE TERMINA ANODE LEAD lurk in the CATHODE TERMINAL REINFORCEMENT the Hotel water of pools; CATHODE SEA Pennsylvania in .aCAP New York City. even drinking MERCURY VAPOR RC AN, DE AEr water being We do not full of the mean to say germs men- that this hotel tioned, and uses the same various other water indefi- lesser cultures, nitely, but just t o o numerous cite this as an to mention. example show- Therefore, in- ing that the stead of using ,same water the water di- could be used rectly from the over and over main pipes, again. The say- they installed ing "that we an ultra- violet swim in purer ray sterilizing water than you apparatus drink at home" which corn- is quite correct. pletely steri- This apparatus lizes the water, also renders a the most OVERFLOW AND Caa.v pleasing atmos- so that phere exacting c u I - to the tures of the swimmers in water taken the cool, invit- from pool ing waters. the Sectronai View Thru Ultra- Violet Ray Lamp Chamber With Partitions, Showing How the Water From (Continued show a corn- the Water on the Swimming page 939) plate absence IsS °ActActed roandt All GermspKl ledubyhtheuPowerfulCUltra-Violet Rays. 878 ELECTRICAL EXPERIMENTER January, 1920'

General View of the Capitol Theater Stage, New York City, Showing the Revolving Tower Effect Used. This Is Filled with Chorus Girls, Both Inside and Out, When It Is in "Full Bloom." Electric Lights Are Used to Outline the Tower Structure. While One Line of Girls Ascend the Second Line Is Descending, Producing a Beautiful and Entrancing Spectacle. The Capitol Theater Is the Largest in the World. The WonIl angelt

ABEAUTIFUL new theater was re- in similar New York buildings. The audi- forward may be accomplished in the least cently opened y in New York, which torium is 175 feet wide and extends south possible time and with the minimum of not only dwarfed picture palaces towards the stage, a stretch of 159 feet. labor. that now flank Broadway, but also Its orchestra floor seats 2,750, and its bal- When thus shifted forward, a semi-cir- out -ranks the theaters of the world. cony seats approximately the same num- cular stairway is placed around the base This particular assertion not only embraces ber ; or a total seating capacity of 5,300. of the tower, hiding its mechanism and the so- called legitimate theaters, but also The balcony is guiltless of the presence of covering the electric cables leading to it the celebrated opera houses of the globe, a single supporting column, due thru the for the lighting purposes. A large iron including the far -famed and gorgeous La application of the most modern Cantilever beam swings forward and locks the tower Scala at Milan, Italy. building construction. so that it cannot topple over or sway. This new theater, the "Capitol," is re- THE CAPITOL THEATER SHOW The tower itself is mounted on a large markable not only for its size, but in its wheel supported by roller bearings. Two location on one of the most valuable sites The entertainment at this theater is stairways lead upward in such a manner in creation, a $3,000,000 plot, and in its unique and marvelous in that the manager that one spirals to the left and the outer unique combination of pictures and other has attempted to combine both "folly" nov- to the right. The inner stairway is cov- forms of entertainment. It extends 109 elties and high -class "motion pictures." The ered by very fine gauze, which makes it in- feet on Broadway, 269 feet on 51st St., and scene depicted in the photographs is from visible ordinarily. The rotating mechanism thence 200 feet south to 50th St., where the the closing scene of the "Ned Wayburn Re- of the tower consists of a worm -gear drive stage is located. This feature in itself re- view." The feature scenic effect is a re- which is rotated by two men in back of quires a frontage of 157 ft. markable revolving tower filled with girls. the drop or back scene. The theater presents an unbroken front This tower is shifted into position on a Now, for the effect ! A stairway- -like- of conventional, monumental design, orna- set of tracks from its resting place back wise collapsible, so that it may be moved mented by a solid row of pilasters, seven- stage, being mounted on a carriage which out of the way when not in use -connects teen in number, the longest line adornment is mounted on wheels, so that its movement to the top of the tower, but the means of January, 1920 ELECTRICAL EXPERIMENTER 879 approach to the tower is hid- Immediately below the base den ; a sliding trap door com- are three commutators which municating directly with a supply current for the illu- door in the tower. The chorus mination of the tower. Large girls, hidden from view, sud- brushes make contact with the denly are seen to descend on cummutators, each of which the outer spiral and arrange is directly connected to a very themselves in artistic, graceful heavy rubber covered cable, groups upon the platform of running to its supply base, the the tower itself and the stage. switchboard back stage. After a short period of enter- The . switchboard itself is a taining they are seen to ascend beauteous marvel of simplicity. the spiral stairway to the top It is capable of producing not and seemingly to disappear, only ordinary actual work, but while in reality they descend intense serviceability under un- again on the inner stairway. usual conditions. Its panels Suddenly, the lights illuminat- of the unit type are constructed ing the inner spiral are flashed so that they may be removed on the tower, being made to separately for any necessary revolve at the same time. This repairs. From this switch- causes the girls behind the board, a variety of current gauze -veiled inner stairway to may be obtained and methods be seen as tho in a mist. They for inserting plugs to draw descend constantly, while those any voltage of any form from on the outer are ascending, it are found to conform with thanks to communicating plat- both the fire underwriters' forms between the stairways laws, and laws, if such there at both top and bottom, so that are, for preventing any seri- an endless stream of actors ous accident to those. directly and actresses form a spectacu- responsible for the electrical lar and bewildering maze. side of the show as there is The illustration shows clear- no way of coming in contact ly the arrangement of the with a live circuit, all the tower and its methods of com- switches being entirely con- municating at the top and bot- cealed. From the switchboard, tom chambers, likewise the 110 volts alternating or direct carriage and the rotative current may be obtained. Like- means. The insert view shows wise, 220 volts in both forms. the top dome with its sliding Elaborate rheostats and regu- trap door and the communica- lators allow a gradation of tion means between the two current value which alone is stairways ; likewise the beam capable of producing most holding the tower rigidly in wonderful stupendous effects place. Two steel cables clamped which any stage setting or any to this beam are tightened play may necessitate. by means of turnbuckles act- Fourteen or more projectors ing, in this way, as braces and with variable color filters minimize any lateral swing- enable a diffusion of light in ing tendency which the tower The Revolving Tower Filled with Chorus Girls from the Ned Wayburn all its color values to be di- and its beauties may experi- Review at the Capitol Theater. rected in streams upon the ence. stage and ac.Jrs.

The Loc©moO tIlve Pet1 Ilacope g NemKU By GEORGE WALL

NOW that the war has shown us what periscope in use on an electric locomotive approaching at a dangerous speed, that he an invaluable instrument the modern and two of them are here employed, as can speed up his own train, so as to mini- periscope really is, even to the extent the electric locomotive, unlike its steam - mize the effect of a rear -end collision, if that thousands of our brave soldiers in the driven prototype, is liable to run in either such really is to occur at all. trenches in many instances owed their directions, for it is reversible. We have often heard of railroad engi- very lives to the efficiency of the trench For one thing, the locomotive periscope neers racing their trains so that the run- periscope for looking over the parapet will enable the engineer to see at all times away train on the same track behind, either without exposing their heads or bodies, we any signals from the rear of a long freight cannot catch up with him, or else if it did, are not surprised perhaps to see the peri- train, such as the swinging arm signals, and in view of the fact that his own train scope adapted to the requirements of mod- or swinging lantern signals, given by brake- was traveling at a speed approximating em railroading. Why not use the peri- men atop the cars, and he also can see the that of the pursuing train, that any colli- scope on locomotives, both electric and track far to the rear. This means that sion between them would be very slight, steam? It should save many lives for if he should see a train on the same track compared to one that might occur between more reasons than t h e stationary o r one. Its use should slow -moving t r a i n certainly prevent and the rapidly-mov- many heretofore un- ing train at the rear. avoidable occurrences No one can look in such as rear-end col- lisions, etc. two directions at the The periscope for same time ordinarily, locomotives employs a but thanks to the lo- large mirror, so that comotive periscope, the engineer need not the engineer of to- focus his gaze accur- morrow will be bet- ately on a small eye- ter off so to speak, piece, as in the sub- for after a little prac- marine periscope, for tice, he can keep a this would hardly do sight ahead as well as owing to the many duties constantly behind, by simply thrust upon him. The I IIII glancing periodically accompanying i 11 u s- and regularly at the trations show the periscope beside him. 880 ELECTRICAL EXPERIMENTER January, 1920

70cD:15hcAng SmoRe L T11E dust and fumes which are dis- ess. He need only stand where he can charged from the stacks of iron How Tlìa®usands watch the stacks leading from the treater, furnaces, cement mills, and many ®ff n®IlIlarz's while some one opens and closes the treat- other industrial enterprises, not only ing circuit. When the current is "off," represent a waste of valuable ma- Are ReeIlaIlr1ied by the familiar clouds of smoke pour out; terial but also frequently constitute a nui- but when the current is "on," the smoke sance. In the interests of economic con- SmineIl4Ilng' Companies vanishes, and nothing but a fine vapor can

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Another Group of Tension i ft D. C. Rectifiers Switch-Board. and

97 _ ", D. C. Rectifier 100,000 Volt Close -Up of Eliminator. Used In Smoke External View of Electrical Treater -Tubes of Smoke and Dust Eli minator.

servation it is desirable to eliminate the be seen. Final proof of the effectiveness loss of material represented by this dust, Outlet stab of the operation is provided by the car- and for civic or legal reasons it is often loads of precipitated dust taken out of necessary to suppress the nuisance caused the collecting bins. by its discharge into the atmosphere. Such cities as Pittsburgh for instance have long USES OF ELECTRICAL PRECIPITATION been known for their smoky and objection- Electrical precipitation processes are now able atmosphere. being used successfully in lead and copper While there are several mechanical and smelters to reduce metal losses from the chemical methods for collecting or suppres- stacks and to eliminate smoke nuisances; sing dust in furnace and kiln operation, they are in general limited in application in cement plants to collect potash and by conditions of temperature, acidity, and cement dust ; in acid plants to recover acid similar qualities of the product to be fumes; and in rock crushers to suppress handled. Electrical precipitation has few the dust nuisance. The process is also be- limitations of this sort and is generally ing applied to iron blast furnaces to elimi- applicable for collecting suspended solid nate the ore dust and to recover potash and liquid particles of every description, values; to gas plants for removing the whether acid or alkaline, from gases of dust, tar, and lamp black from the gases; widely varying temperature. The electri- to locomotive roundhouses and power cal method is simple, economical and effec- plants, located in centers of population, to tive, and has been successfully operated in Conveyor ee from the a great number of plants of various kinds. a remove the soot and cinders How Electrified wires are Suspended In smoke; and to industrial processes produc- A visitor to one of these plants is easily Pipes Thru Which Dust Laden Gases Are convinced of the practicability of the proc- Past (Continued on page 931) January, 1920 ELECTRICAL EXPERIMENTER 881 The ERectriczR Enggneer Woltz i o WinfieIld OCC®T THE DAILY WORK OF catalogs, of which THE ELECTRICAL ENGINEER every engineering of- fice has a complete (jW does the file, in order to de- electrical termine the dimen- engineer sions of any stock H work, and parts such as wheels, of what pulleys, bearings, etc., does his work con- which he may use in sist?-is probably a laying out the funda- question uppermost in mental design of the the minds of not only first machine. embryo students of THE ENGINEER - electrical engineering, DRAFTSMAN but one which exists in the minds of par- The rough pencil ents of young men or pen- and -ink about to choose a ca- sketches with a few reer as well. Of notes on them cover- course, it is impos- ing the over -all de- sible to describe the sign and "high lights" daily routine or the A Busy Scene In th e Drafting Room of the General Electric Company's Wo ^ks. Here which come from the the First Tangible O utlines of the Engineer's Ideas Are Brought to Life in the Form of general work carried Drawings and Blue- Prints. consulting engineer, on by an engineer to reach the drafting fit any one type of room, and the chief engineer or class of work, as there are so idea, he makes the first design from the draftsman, who is invariably a designing many ramifications of the engineering pro- idea as supplied by someone else in the engineer of high responsibility and thor- fession today that it is hard to find two organization or by a department of the oly experienced. Under the head of this engineers engaged on identically the same organization, or again, possibly by a pat- Department comes a staff composed of work, or who accomplish their work in ron, who desires to have a certain machine what the layman generally knows as the the same manner, in one engineering office. built. Many times the outside patron sim- "draftsmen" and "tracers." But once the ply has a hazy idea as to what he wishes to accomplish, but he is firm in his belief that it can be done -and it is, let us say, up to the consulting engineer who stands at the head of the engineering organization of his concern, to work out in his mind and develop the nucleus around which the future device or apparatus is to be built. ICONSULTING The consulting engineer is invariably but ENGINEER not always, a college- trained man, and one who is a thoro mathematician. He is an expert with the slide rule and knows his text -books the same as a musician knows his notes and keys. In his early training he has wisely read all the books on the various subjects appertaining to his pro- fession that he could possibly procure, and he has also providentially, in practically all cases, provided himself with a good The Consulting Engineer -He Is the Man working library of handbooks and text- Who Must Understand the Technical De- tails of an Electrical and Mechanical De- books, which will be of real service to sign. He Must Be a Good Mathematician. him. The carpenter, plumber or ma- chinist works with his tools, and these tools he must have to accomplish any cred- Blue- Printing by a Machine Fitted with Let us consider how the electrical engi- Powerful Electric Lights Which Take the case and itable performance of his work. The con- Place of Sunlight, Used In the Older Process. neer does his work in a typical sulting or electrical engineer works from The Drawings Are Made on Tracing Cloth. under an organization such as exists in a plant. his hand -books and text -books, in general, large manufacturing coupled with his experience on various de- erstwhile layman has been initiated into THE CONSULTING ENGINEER signs with which he has come in contact the intricacies of the draftsman's every- during his career. Right here we may ad- day life, he will be surprised indeed, to The consulting engineer is the man who vantageously study the mode of living, for learn what mass either conceives the original idea from a of detail the draftsman, that is really what it amounts to in the (Continued on page 955) which a machine or device is to be built, final analysis, of the thoroly trained engi- or if he does not originally conceive the neer, no matter what line he happens to be engaged in. The carpenter for example, may build a house, or he may even design a building, but the writer has noted from personal experience, that very few carpen- ters or builders, who may erect such a complex structure, keep any data on the building as to its cost or the different di- mensions for future reference, but the en- gineer, particularly the consulting engi- neer, will bend every effort conceivable to acquire all empirical data on any machine which he is interested in, and particularly, any machine or device that he has de- signed, and which has been built from his specifications. This should be so in every case, not only for the engineer; and as aforementioned, the engineer really lives his life in this fashion, and it does not The Draftsman, Whose Work Generally Laps hurt him either, for he grows to be meth- Over Into the Engineering Line More or odical and exact without being taciturn Less, So That When He Has Had Consider- The Engineer Finds His Happiest Moments able Experience He Frequently Holds a Po- or worrisome. Thus it is that the consult- When the "Child of His Brain" Has Been sition as an Engineer- Draftsman. ing expert refers to his books and also to Built and Made Ready for Test. 884 ELECTRICAL EXPERIMENTER January, 1920 'qcai THE upper left and lower right pho- across the gap the same as tho he were staff of a large New York newspaper. A tographs here reproduced are from transmitting. Funny-no, we must allow the girl had been murdered in New Jersey and the Pathé Serial -"The Third Eye." movies some freedom, and cannot keep them he was sent out to get the dope and in- The villain in the photograph to the dibwn to absolutely conventional means of cidentally happened to be the first to make left is shown with a complete set of connecting and operating such apparatus. an examination. A short time prior to wireless instruments in the act of This play is a mystery story in about this he had read quite a little of the retina "sending," and the is shown leaping spark episodes, in a is retaining an image of the scene or object across the spark gap. This is in eighteen which man mur- it last scene the cel- dered in moving picture studio. saw, so he promptly photographed lar retreat of a gang of crooks whose radio a The it on the murdered person. When the apparatus is supposed to be used for com- camera which has been focust to the point plate was developed, it actually showed an municating with the master criminal living mysteriously starts to turn without any image, but the image was very imperfect in his palatial summer home on an island off visible means and take some movies of and no definite indictment could be ob- the coast. He has just been ordered to start the murderer. When the film is developed, tained on the image alone.

Villains In Order to Be Real (or Reel) Vlllainish Must Have Nifty Radio Sets. So In the Upper Left Photo They Have Given Him All Sorts of Diabolical Things to Play With, Blow Up Houses, Etc. In the Photograph at Its Right, Is the "Iron Maiden "- Electrifled! "Now, Eileen (Lower Left) Don't Get Too Ticklish with the Oudin High Frequency." At the Lower Right, Is Nature's Photograph of a Movie Murderer, Permanently Inscribed on the Retina of His Victiml?? sending a message, which latter will be it is found that the hero is indicted for the The lower left and upper right photographs received at another station and a spark murder, according to the "circumstantial are taken from the Universal feature -"The will fly across the gap, as a result, igniting evidence produced by the developed film; Great Radium Mystery " -in which a one - a can of dynamite and completely dismem- but was he the murderer? Of course no gram tube of radium valued at $120,000 is bering the anatomies of the hero and hero could be. actually being used. The entire play is heroine. Of course in the "movies" the In the lower right picture the author based on the fact that a radium mine in apparatus must be arranged so as to get has made use of the theory that the retina Montana is discovered by two brothers and the most pronounced effect, hence the mas- of a dead man's eye retains for some time they had either mined or manufactured sive coiled wire ; which, if used in a after death, an image of the last thing it radium in such quantities that the whole modern wireless station, would be laughed saw in life. manner of living and the history of the at and ridiculed, as the impedance pro- In corroboration of this, Mr. Lewis, the entire world would be changed at one duced by the coils leading to the high ten- publicity manager of Pathé films, cited a new living conditions cause unnecessary case of his own experience which occurred single stroke, and sion condenser would humanity over -night. Het-16e, losses. To watch a movie man receiving before he entered the "movie" game, at be thrust upon a message, one sees the spark crashing which time he was acting on the editorial (Continued on page 961) January, 1920 ELECTRICAL EXPERIMENTER 885

AMBRINE FOR ELECTRIC AND X -RAY BURNS. Aaterná VV Ilah EngIlne RunnIln Ambrine is the discovery of Dr. Barthe Ahead de Sandfort a surgeon in the French navy. He believed, as most other surgeons be- Mo II°3IIPLET lieved, that open surface wounds should be CHARLE5 treated with a dressing which would ex- clude all air and which could be removed without disturbing the newly formed epi- thelium. Ambrine is the wonderful prep- aration used with such success during the war to heal the burns from "liquid fire" attacks. Ambrine is a neutral paraffin and resin compound, which is prepared according to a secret formula. On account of its organic composition, it is impossible to analyze. The equipment comprises one fine varnish brush, or preferably a paraffin base atom- izer ; one double boiler ; one electric drier ; absorbent cotton divided into very thin layers. When the patient enters the hospital, the clothing is removed; blebs are punctured, but not excised; and the entire area is thoroly dried with an electric hot air drier, or a fan, so that there is no moisture on the surface (an electric fan or common fan may be used). The wax is applied to the burn at the earliest possible opportunity, The Newest Thing in Boat Steering Devices -a Split Rudder, Which Permits of Running either with a fine varnish brush or atomizer in Any Direction, Even Backward, with Propeller Turning for Ahead! Photo at Right -3 in Own Length -preferably with an atomizer. It is diffi- Exposures on 1 Plate, Showing Boat Turning Its after Being Suddenly cult to regulate the temperature where the Stopt Short In Its Forward Course. brush is used; it is more or less painful and ANE of the large American electrical thick, each plate the same size as the nor- concerns has recently equipt a 25- mal rudder used on this type of boat. The ft. motor boat owned by Mr. W. B. rudder post consists of a steel rod inside a O Landreth, Deputy State Engineer steel tube, one plate of the rudder is at- of New York, with a simple yet tached to the tube and the other to the remarkable reversing and control rudder, rod. The boat is equipt with two steering with a view to showing the possibility of wheels, arranged side by side, one wheel eliminating reversing turbines from the to operate the rudder affixt to the tube, large turbine propelled ships. and the other the rudder fastened to the This boat is capable o,backing up with rod. The manner in which the rudders are the engine running in a forward direction, affixt to the stern of the boat is best shown but the most' valuable feature is its ability in the side view herewith. This shows the to turn around in its own length. With two rudders close together in the position this rudder the boat can be maneuvered for normal cruising, when they are used without steerageway; that is, with the rud- the same as an ordinary rudder. der placed at right angles to the axis of The two steering wheels, placed up' for- the keel and with engine running at full ward in the launch, are on the same axis speed, the boat will stand perfectly still and when locked together operate as one and then by making a slight adjustment of wheel for ordinary cruising. But when the rudders, the boat will turn around in its the boat is to be turned sharply or re- own length and continue to do so until the versed, the wheels are instantly unlocked adjustment is changed; and during the pro- and released, se that they may be revolved Electric Burns Are Among the Worst. Am- cess of this circular motion it can leave in opposite directions to manipulate the brine -the Wonderful New Wax Treatment for any point of the compass at full speed. rudder plates. For Burns Developed During the War, Has illustration of the maneuvering Been Very Useful and Healing in All Such As an It is truly remarkable how easily the Treatment. X -Ray Burns Can Be Treated qualities of the rudder, this boat was run its own By Ambrine Also. boat can be made to turn within into a 40 -foot slip full speed ahead, turned length. By placing the rudders in the posi- around and came out bow first without ' indicated in the diagram chart here- touching either side of slip. tion there is a tendency to brush away and with the boat will turn around in a few The rudder on the Landreth boat, the and travel back up its own wake. traumatize the new epithelium and granula- invention of H. O. Westendarp, of Boston, seconds tions. consists of two steel plates 3/16 of an inch (Continued on page 939) Chemical Burns. If the burn is acid, an alkali is used to neutralize the acid present; and if alkali, an acid is used ; the burned area thoroly dried and wax applied. In one case several acid burns, first and second degree, were treated in which 5 per cent. of the surface of the lower extremities was involved, which were cured and the patient in each case was discharged from the hos- pital in 11 to 12 days, with absolute freedom from pain during treatment. X -ray Burns. Experience is too limited to express any opinion other than the relief from pain which the dressing assures. Dr. AHEAD/ Oh engine at fu // speed. Mayo reports one case in which an excision ASTERN/ tng/ne riming fu// speed AHEAD "o/ /the /ime. had been done for a sluggish burn of more than one year's standing in which the granulating wound covered over satisfac- torily with the wax treatment. It will probably have some value in the treatment of X -ray burns. Electrical Burns. Holtze reports excel- lent results in the treatment of electrical burns (30 cases). Pain was relieved and patients recovered more rapidly than with other methods, with no contracting cicatri- cial tissue. He considers the method far The New Compound or Double Pitch Steering Rudder by Means of Which a Boat Can Be superior to other methods and has stand- Run Ahead, Astern, or In a Circle of Radius Equal to the Boat's Length, with the Engine ardized it in his service. and Propeller Running Full Speed Ahead at All Times. 888 ELECTRICAL EXPERIMENTER January, 1920 The M.ao WIl scora. 0-:Each Lecflng Te_escope Dy FLOYD Lo TEA 3R ®W Head of Science Department, Polytechnic Preparatory School, Brooklyn, N. Y. Now II( TEIImESC® ES WORN knowledge of these discoveries, invented the first astronomical telescope in 1610. Galileo's telescope was of the refracting type and an explanation of its operating principles will be given in a later article. There were certain very serious defects in these early refracting telescopes, however, and Sir Isaac Newton set about the inven- tion of another type of telescope which should depend for its optical properties, not upon the refraction of light thru lenses, but upon its reflection from a highly polished concave mirror. His first telescope was a small affair but it greatly improved the definition of the image and eliminated the troublesome color- fringe always present about the images produced with refracting telescopes. Newton quickly followed it with a larger instrument and from that day until this the reflecting telescope has been a strong competitor for first place in tele- scopic achievement and astronomical dis- covery. The immense six -foot reflecting mirror made by Lord Rosse and now in the British Museum is a notable example of the last century. WORLD'S LARGEST TELESCOPE AT MT. WILSON The latest and largest telescope of the world has just been erected in the Solar Observatory of the Carnegie Institution, located on Mount Wilson near Pasadena, California. This optical marvel was made possible by a gift of $45,000 to the Car- negie Institution by Mr. John A. Hooker of Los Angeles in 1906. Mr. Hooker speci- fied that this money should be used for the purchase and grinding of a glass disc 100 inches in diameter and having a focal length of about 50 feet. As the making of optical glass was an unmastered art in this country previous to the Great War, the order was placed with a large firm at St. Gobain, France, in the autumn 1906. Lowering Clamp onto Huge 100-Inch Mt. Wilson Glass Reflector in Order to Lift It from of Grinding Table. An order for so large a disc had never before been received and its casting taxed NO other instrument upon which Man has applied his genius for inven- tion has so broken down the bar- riers of .space and loosed the fet- ters of intellectual bondage as has the telescope. From the days of Galileo and the crude "Optic Tube" with which he made those first epoch- making discoveries down to the giant 100 -inch reflector just erected on Mount Wilson, California, stretches a continuous pathway of steady progress and brilliant achievement. As the novelist, H. G. Wells, says this planet re- ceives no imports save meteors and has no exports whatever, yet these marvelous adaptations of optical glass bring to view other worlds without end, push heaven- ward the bounds of the known universe by billions of miles and enable us to weigh the planets and analyze the stars with mathematical precision and exactitude. THE FIRST TELESCOPE To whom belongs credit for the inven- tion of the telescope has never been def- initely settled. About 1590 a Dutch op- tician, Zacharius Jensen, arranged in a tube a combination of lenses with which he was able to magnify small objects. A few years later a fellow countryman, Jo- hannes Lippershey, experimented with a similar set of lenses and made the discov- ery that a distant church steeple was brought much nearer by their aid. But certain it is that Galileo, the great Italian Note the Perfect Reflection of the Faces in the Polished Face of the 100 -Inch Reflector scientist of Padua and Florence, with no Used at Mt. Wilson. January, 1920 ELECTRICAL EXPERIMENTER 889

was as successful as the first. Prof. George W. Ritchey, of the observatory staff, and under whose direction the work of grinding was to be done then made a trip to France but found it a prac- tical impossibility to cast so A/ mapvi irngq done here mine large a piece of glass at one eye pitee pouring. Therefore the pro- ject of building the telescope R/ghfooy/e must be abandoned or work orism must be begun on the original disc. Without hesitation the latter course was adopted. THE GRINDING OF THE 100 -INCH LENS STARTS Not until 1910 was the disc placed on the grinding ma- chine. The actual work was done by Messrs. Kinny and Dalton. The edge and sur- faces were first ground off un- til the glass measured 101 inches in diameter and 13 1 inches in thickness. This was followed by the rough grinding of the concave surface. The grinding and subsequent pol- ishing and figuring were done almost entirely by machinery. Very fine emery flour mixed ;.Highly pollshed with water and applied by ref/ecfing mirror wooden brushes covered with Go/hers /Of only: cheese cloth did the work of no mr gnilirhin here abrasion. No metal was al- to lowed touch the surface. Lowering the Great 100 -Inch Mirror Onto Cover, Pre- The brushes revolved very paratory to Transporting It to Summit of Mount Wilson. slowly and from the center outward. This first grinding hollowed out glass unfit and to bring to naught long the mirror to a depth of 11/4 inches and years of hope and painstaking labor. But was followed by a second grinding in a new kind of grinding tool devised for The "Newtonian" Telescope Here the Image of the Heavenly Body -Is Reflected which still finer emery dust was employed the purpose solved the problem. It con- from the Mirror at the Bottom, Up to the and the utmost care was exercised. sisted of a 1,500-pound plate of the same Prism and Lens Magnifying System Shown. Then came the polishing -a far more ex- size as the glass, which exerted a uniform acting task than the grinding and requir- pressure at every point of the surface and to the utmost the capacity of the plant and ing a series of the most delicate and thoro thus smoothed out the inequalities of curv- the skill of the master craftsmen who ex- tests. One difficulty early encountered ature. ecuted the work. After eight failures the was the discovery that the glass was as- One of the most important series of disc was cast in 1908. It was packed just tigmatic, i.e., the curvatures at right an- tests consisted in determining the effect of as it came from the mold and shipt di- gles to each other were not uniform. temperature changes on the qualities of the rectly to Galveston, Texas, by water and Altho these curvatures differed by only glass. It was subjected to variations rang- thence by rail to Pasadena. In the rough .0016 of an inch, it was known that even ing from 30 degrees to 105 degrees Fahr. state the disc weighed 51/2 tons, it was a this slight variation would produce seri- and was found to suffer no harm if these little more than 101 inches in diameter and ous distortion of images. For a time this changes were gradual. Rapid changes did was 13 inches thick. A special building baffling defect seemed likely to render the (Continued on page 942) was erected for its grinding. But a close inspection of the disc revealed the fact that it had been cast in three layers and flaws were disclosed which seemed to render it unfit for optical use. Word was sent to St. /$. Gobain and a new furnace capable of hold- S ing 20 tons of molten glass was erected. Two E tI I I I I II II I I III I I I I I I I I I I I I I I I I I f more attempts were made but neither , \0/.

Usual Mount- ing of a Re- Ai?..ma/ rorwer flecting Tele- mirror Convex scope of the mirror Cassegrain Type. Here the Star -,. .. Image Is Re- , flecten Up- ward Again i. ;, to a Second . . and Smaller Mirror of the Line dl-ocir Convex Type, Large reflect/iv geore0 for revel- Whence the mirror / weg /e /escoppee in I m a g e I s / step wirkobed Projected Downward Thru the yy !)r.,/ xa Hole to the Fi NMI Magnifying Eye Piece. ' /. / \_. \i tick, //re_ . mirror S t. egep/PCe Diagram of the Mounting of 100 -Inch Re- flector at Mt. Wilson. Large Pedestal (North M1Il11llllllllllllllllllllllllllllf One) Bears 40 Tons, Small Pedestal (South) J Bears 60 Tons. Large Wheel at Lower End l u of Polar Axis Is Toothed Wheel Engaging ; with the Clock Mechanism. Rectangular Yoke Is Shown Only in Side -View. 892 ELECTRICAL EXPERIMENTER January, 1920 The Stfutehuce of E ectAcIlty By Dr. Alfred Gradenwátz IN the course of the last few decades ACIlance fint® She W®£c'Rd individual atoms. Such particles, however, our views regarding the nature of elec- can neither be produced by crushing nor tricity have undergone, great changes. ®{l the MfinIlont cIl by stamping. According to the process Once upon a time a theory was gen- suggested by Ehrenhaft they are produced erally held, according to which two cDT a CeTs1i Il ciu cbteEC by means of the very electricity the nature imponderable fluids, a positive and a of which is to be ascertained, an electrical negative one, would by their shifting ar- Globules of such incredibly small dimen- arc being made to pass between mercury, rangement give rise to the electrical phe- sions are arranged between two parallel, silver or gold electrodes, which are so in- nomena then known. Maxwell in England horizontal plates connected tq a positive tensely pulverized or evaporated that the and Hertz in Germany, however, at the and negative tension respectively and, ac- intermediary space is filled up by a rain end of the last century introduced another cordingly, constituting an electrical con- of particles some millionth parts of a centi- theory according to which electrical and denser, the globules themselves being meter in diameter. electromagnetical phenomena would be due charged negatively. Each globule then is If, now, the surroundings of these minute

Fig. 1 -Prof. Enrenhaft's Experimental Laboratory Apparatus Used in Examining the Structure of the Electron and Atomic Family. Fig. 2- Powerful Beam of Light Rendering Minute Particles Visible in Microscope. Fig. 3- Minute Sulfur Globules Mixed Up with Particles of Other Shapes. One Division of Ocular Scale 35.8 x 10 -° cm. Fig. 4- Minute Silver Globules Under 2870 Fold Magnification. One Division of Objective Scale: 1.10-3 cm. Fig. 5-Zinc Wool (Not Globular) Powder 1305 Fold Magnification. One Part of Scale: 11.5.10-5 cm. to ether waves of a similar nature to those by its weight drawn downward, while the metal globules be lighted up with an in- of light. electrical tension acting on its charge is tense beam of light, a microscope pointed More recently there has, however, been pulling it in an upward direction. If, now, vertically to the beam will disclose a sight a general tendency for a revival of material the condenser be connected to a tension comparable to a firmament of surprising just sufficing to conceptions on the nature of electricity. draw the globule slowly splendor and variety of colors ; each single towards the upper plate, the upward pull, luminous point falling, under the influence The same as matter is made up of indi- which is dependent visible on the charge of the of gravity, in vertical trajectories, the small elements, atoms, electricity globule and the tension applied, will ex- stronger ones more rapidly, the weaker would consist of elementary quantas, elec- ceed the weight of the globule. The ten- ones more slowly. The falling speed of trons. sion applied is afterwards reduced by de- all of them is, under the microscope, accu- In opposition to this doctrine an Aus- grees, until the globule just falls down- rately measurable. Furthermore, each of trian scientist, Dr. Felix Ehrenhaft, Pro-. wards in a vertical direction, thus confin- these minute particles will, under some fessor of Physics at the University of ing the tension between two boundary mysterious impulse, perform vibrations and Vienna, however, already at the Königs- values, the rising and falling tension, re- move ,to and fro on zigzag lines. These berg Congress of Naturalists in 1910, drew spectively. Inasmuch as these tensions are Brownian movements, so far known only attention to the fact that this would -be read off from a sensitive voltmeter, the in liquids, are due to the nearly molecular minimum charge -the electron charge - charge of the globule thus is ascertained dimensions of the particles in question. though being ascertainable as average with the same accuracy as its weight. These metal globules having been charged value, is inaccessible to human observation In order now to obtain globules as small, with variable amounts of electricity, Prof. in the individual particles. In a paper re- and accordingly charges as minute as pos- Ehrenhaft each time-in accordance with cently read before the Austrian Society of sible, it would be best to cause individual the above -determines the tension at which Architects and Engineers, he exposes his atoms to float in the interval between the a rising or falling respectively can be ob- further researches on the same subject, condenser plates. This, however, is un- served in the microscope. He therefrom which not only give an insight into the feasible, atoms being invisible even to the ascertains the actual charge, the size -or very structure of electricity, but at the same most perfect optical instruments. In fact, weight -of the particles being known. time into the physics of minute particles - the smallest particles ascertained by means Apart from the mechanical method -by of the order of the millionth part of a of our best optical instruments have diam- means of the speed of falling-this weight centimeter. eters about a hundred times greater than (Continued on page 961) January, 1920 ELECTRICAL EXPERIMENTER 893 How Does Su.hamerged. Lady Breathe?

This clever invention, or rather illusion, apparatus is particularly intended to mystify and afford entertainment. By means of this device the performer, let us say, a lady, appears to observers to be totally submerged and to live and breathe in the water, the same as in the air, even to eating, drinking and smoking. The illustration shows how this trick is performed. A watertight compartment is placed at the top of the structure, while the whole affair is housed in a covering either with cloth or other suitable material. Sev- eral water -lilies or other flowers should be arranged in the manner illustrated, one - half of the lilies, for instance, being rigidly mounted inside the glass- bottom water tank, while the lower and large part of the stem r +. uunl IIUN ïir is placed in the compartment to be occupied MVPeih,., I IG'I by the performer under the glass bottom of the water tank, but in exact alignment with the upper portion of the plant. In this way it is impossible for an observer looking down from above to see any break in the stem of the plant, particularly when the surface of the water is ruffled, as for in- How Does the Lady Under the Water Breathe? It Proves Very Mysterious to the Unin- stance may be occasioned by allowing the itiated. The Answer Is-She Is Not In the Water But In a False Compartment Below the water from the supply pipe to drip slowly Glass Bottom of the Water Tank. into the tank at the top, or else by pro- viding a slight draft of air from a hidden tank unknown to the observers or audi- apparently submerged in the water con- pipe, the stream of air being blown over ence. This trick can be shown on the stantly. In this case the lights can be the top of the water so as to create ripples. regular stage by means of a large mirror turned on and then off in the opening and It goes without saying, of course, that or series of mirrors placed just back and closing presentation of the illusion, or the the performer, whether lady or gent, has above the tank so that the audience can see curtain may be raised and dropt at the to enter the chamber underneath the water the movements of the performer, who is opening and closing of the performance.

A Novel. German T,ench LIl .h To obtain a light with this The casing of the flashlight is finished device which was built so as with a substantial oxid effect, so as to to withstand heavy wear such withstand the weather while a braided as is encountered on the battle- cord attaches to two rings on the cas- field, you simply pull the chain, ing, so that it can be suspended from the the lower end of which can be neck of the user while he pulls on the generator ring as he walks along. The lamp throws a good beam of light, the InIIIIIIIIIIIIIIIIIIIIII111111111IIIIIIII1II111111111111IIIIIIIIIIIIIIIIIIIIII llllllllllllllll11l11 bulb itself being a small screw -base type, fitted in a reflector with a lens in front The "Heinies" Ran Out of of it. The dynamo generates a low volt- Flashlight Batteries and Mate- age, equivalent to a few cells of battery, rials As Well As Their Breath, and the current is surprisingly steady - and Here We See the Conse- almost flickerless in fact, when the gen- quence-a "Dynamo" Flashlight. erator chain is pulled in a fairly rapid A Pull on the Chain Ring and manner. the Dynamo Was Spun Rapidly, There are several American concerns de- Generating Sufficient Current to veloping a magneto light of this type -i.e., Light the Five -Volt Bulb. A is rapidly the Lamp one in which a small dynamo Lens Was Fitted Over spun by hand or finger action to produce Bulb. electricity for lighting the lamp, instead of depending on a battery for the purpose. The problem appears very simple, but ap- I Illi IV111111111IIIIIllIIVI1IVVi11IIII01lI0I1lllll111IIIMI1I1111 parently is not as easy to solve as would at first appear, especially in a small lamp. seen in one of the photos, and to which a finger ring is I- Soft sheet irgo /amino/ans. 2- Prnpe/ /ing (trio in grooved attached. The propelling chain drum. 3- Pinion.iadoma /ic dutch on armature sheTO. 4 -taro/ spnhy: »ido cdoál S s figdrah rthemeád aria M pea on this generator was about 14 inches long, having a gear in- side of the dynamo casing, The accompanying illustrations show an arranged to co -act with a ratchet in such a ingenious design of dynamo -electric trench manner that the six legs of the permanent light which was captured from a Boche by steel -magnet armature were spun around an American doughboy. As will be recol- repeatedly in one direction: The details of lected it was very difficult and in fact im- this clutch mechanism are shown in one of possible to secure the many necessary ma- the illustrations, and it is very clever in its terials in Germany during the war, to design. The rotor is composed of three manufacture the hundreds of thousands of U- shaped steel magnets, as shown in the dry cells required by the Teutonic army drawing, and the three magnets are and navy. The electric flashlight was one clamped together to form an armature of the most used devices in the lines. or really a rotating field. The stationary P The Germans, however, were not so for- coils of which there were six, were wound ó-¿'tempt /ester/ armo/uri 111047/1113. .7-Jr/no-lure mamiedoo heavy copper magnet skeet. d- Sprorg cc/vale paw/ 9- Spnrq V- Par/ linger tunate, at least in the latter part of the with fairly wire, fosknrd Io p/niorl //- AC wins Jo /o s. et war, and so it was that we find this inter- about No. 24 B. & S. gage. These are relic of the Teuton military regime connected in series alternately, in the The Interior Mechanism of the German esting Trench Light, Showing How the Dynamo in the form of a dynamo excited flash- usual fashion, so as to give north and Armature Was Arranged To Be Spun By a light. south polarity successively. Chain and Drum Clutch. 896 ELECTRICAL EXPERIMENTER January, 1920

cm, !t) y JOo?J+tm1PH KLNAU5p THE MAGIC "FIRE- BOWL" ASHORT time after I stept Placing the bowl upon the table off the train, I arrived at the and drawing his chair alongside of pretty Long Island home of mine, he said, "Do you think that will Professor Henri Hargrave, do ?" and seeing that no reply was the noted magician. The ser- forthcoming, he added, "I think so. vant admitted me a few moments But what's the matter with your later, and ushered me into the pro- `weed,' is it out again ?" fessor's study, requesting that I make This, in reference to my cigar myself at home. Somehow or other which I had forgotten about during I never was able to do this when the performance. Lighting up both there are surroundings of the same our cigars, he continued with his dis- nature as those at the Hargrave es- course. tate, consequently the servant's in- "I think that the best way that I vitation was, I am afraid, superflu- can explain the trick is to show you ous. how it is done, and then you will be The spacious study filled with more able to grasp the meaning of weird, mysterious objects was now the various parts and their relation under scrutiny, each piece of work- to each other, together with their manship was critically examined. proper functioning." While thus engaged the Professor Reaching for the bowl on the table entered, just as I turned to meet he hung it from his vest under his him. coat in such a position that it cov- "Well, well, how are you ?" he ex- ered the lower left vest pocket -then claimed, presenting his hand in a secured the cloth. Waving it in such hearty shake. "Have a chair, have a manner that one is convinced that a cigar, have a- What can I do there is nothing on either side, he for you ?" slung it over one arm, covering, in These questions were fired at me this way the movement of the other so quickly, I stood there wondering hand in it's journey to the bowl. which one to answer, and while still This time it was quite apparent that pondering, altho for only a short the bowl did not come from mid -air time, Professor Hargrave thrust one as it seemed to do originally ; but of the cigars between my teeth, the clever manipulations which the eliminating the necessity of answer- performer executed could only have ing his inquiries, been gained thru practice. After a few puffs on his cigar, he "You see," he exclaimed, removing rose to his feet and said, "Well, 'Old the bowl from the table, upon which Timer' -what shall we give them he had replaced it, and handing it to this time? Will the 'fire -bowl' do ?" me, "The bowl is suspended from I nodded in the affirmative. Making Fire While You Walt and So Simple That Anyone this little hook on the edge, from Can Do It. Read on MacDuff, Read "Don't shake your head, because I On. the performer's belt, and held in a can't hear it rattle," he added joc- vertical 'position, being covered by ularly, repairing to the back of the study. While thus engaged with his little epi- his coat. In its center you will note a small A few moments later he stept forward gram, he lifted a cover from the table hollow saucer -like affair, which communi- nearby and placing it on the bowl, extin- cates directly with a long tube. This tube guished the mass of flaming gases. Re- slopes a trifle so as to allow its contents to moving the cover again with the same speed which characterized all his motions I beheld the same bowl, which only a mo- ment before was belching forth streams of MIIIl11111IIII fire, full of flowers of all hues and shapes!

Method of Making a Deck of Cards Which You Should Never Use in a Poker Game Unless You Care Nothing for Your Life. The Cards Clamped in a Wooden Vise Are Shaved Down at One End, Whence by Simply Re- versing Any Card It May Instantly Be With- drawn from the Deck, the Fingers Being Placed as Shown. The Above Drawing Depicts the Construction of the "Fire - Bowl." The Tube Containing Alcohol Is Seen Slightly Inclined, Likewise, leak out when the bowl is placed on a the Position of the Pistol -Like Device for level keel. The tube is of course filled Setting Off the Inflammable Mass. Slight Pressure on the String Is Sufficient to Cause with alcohol or some other inflammable the Mass to Burn, Its Flames Reaching to a material, in an upright position, whence it Height of Four Feet. acts much the same as a bottle with it's cork removed. waving a large red cloth in his hands. "Gently sloping toward the central tube Showing both sides of this repeatedly, he receptacle is a round sheet of asbestos, cov- suddenly produced from its folds a nickel ered with a layer of absorbent cotton plated bowl, from which poured forth fastened in place by wire, and sewed onto streamers of fire which licked the ceiling. the asbestos. The asbestos sheet holds its "You will note that there is very little position by virtue of several sheet iron 'gift of gab' necessary for this trick. It legs, which are fastened to the bowl with depends more on the result than on the ordinary solder. ability to talk. I've performed this same "So much for the bowl and it's reser- Now we come the ig- stunt before all the crowned heads of India, Note How the "Fire -Bowl" Is Suspended voir. to method of the big heads of America and the bone- from the Belt. It's Great to Have a Little niting the inflammable mass. This con- heads of Germany, and it never Heat Under the Belt in These Days of sists of a simple holder which will take an fails to "Prohib.," and Just Imagine! -"Real Alco- produce an effect short of miraculous." hol" Is Used as Fuel. (Continued on page 925) January, 1920 ELECTRICAL EXPERIMENTER 897

O cficaliChe EC iExperiTTìe ts y AL ERT W. WBII4SDCo» HEATING THE HOUSE face on account of the air of the room ing effect and may cause the furniture and T the outset the writer wants to im- that is in contact with this surface becom- woodwork in the rooms to crack and split. press upon the reader that he is ing overheated. Stoves largely heat a room By evaporating water in the hot air pas- not aiming to pass upon the merits by convection, that is, by heating the air sages the dryness of the air may be re- of the various commercial heating that is directly in contact with the stove, duced. systems now in use, but merely in- and when this becomes heated it rises and tends to give data on some of the systems gives way to the colder air. and fuels as used for heating in There openings slides and certain are or draft Sleam ,(0' dampers on the stove which perform spe- (1 cial function's and few people bother them- / \ i; selves to find out their uses, being content 1 r' \ ß with merely adding coal as the fires need ;.r. '__` it, not thinking of the waste of fuel caused t t water >.=-

in this manner. The openings at the bot- 1 I, tom of the stove should be so arranged as I Radiotor + 1 to completely shut out the air if necessary, t or stove thereby controlling the fire. This method f i I is much safer than the practise of shutting r0-,- JI p` the damper in the pipe as this will drive the products of combustion into the room, O 1HH' y-ice which if it occurred during the night, and Ill .a , more particularly if abates, __fY_ _t_,_ - the wind would - _. cause to be liberated the dangerous sul- fig7 fig8 cc phur dioxid, carbon monoxid and the suf g:- _a focating carbon dioxid to the detriment of Fig. 7-Let Us Place a Partition In a Chim- ,,,,,,,,,,,,,1111,11,1,,,,illi,i,,,,,,iii,,,,,i,iiiii1,1,,,,,1,111,,,,,1 ney with the Bottom Closed As In Fig. 1; the fg.4 Candle Will Continue to Burn, for Now the Cool Air (More Dense) Flows Down on One Fig. 4-Like Fig. 1, When a Room Is Heated New Chemistry Side of the Partition and Pushes the Warm with the Windows Closed Both Top and Bot- Air Up the Other. om the Highest Efficiency of the Heating Series Fig. 8- Illustrating a Familiar Example of System is Not Obtained, to Say Nothing of The publishers have great pleas- Heating By Convection and of Convection the Consumption of Unnecessary Fuel. While = ure in announcing that they have Currents in Air. For Laboratory Experiment the Results Are Not So Vivid As in the Case See Fig. 9. Where a Candle Is Burned As in Fig. 1, the arranged for a new series of EX- Fig. 9 -Let Us Place Some Pieces of Ice In a Principle Is the Same and the Heating Sys- PERIMENTAL CHEMISTRY papers, Test Tube Fastening Them There with a tem Will Fail to Work Satisfactorily If Pro- to be prepared by Prof. Floyd L. Coll of Wire and Pour In Water Till the vision is Not Made for the Escape of Foul Tube Is Nearly Full, and Then Hold It Over Air from a Room, As the Fresh Air Will Not Darrow, Instructor in Chemistry a Burner So That the Heat Will Be Applied Continue to Flow in Unless an Equal Amount and Physics at The Polytechnic At a Point Covered by the Water and We Escapes. Preparatory Country Day School, Will Show That the Water Above the Ice Fig. 5-A Fair Method of Ventilation with May Be Boiled, While There Is Ice Only a Radiator By Window, But Not the Best. Brooklyn, N. Y. Prof. Darrow is Short Distance Below. Fig. 6 -Here a Circulation of Air Is Main- the author of numerous articles and tained Constantly, with the Window Open Top and Bottom. books on the subjects of Chemistry In the use of Steam with indirect radia- and Physics, and possesses a clear tion it is convenient to have steam coils localities that demand certain heating sub- and very interesting style of writing in the lower part of the building so situated stances be used on account of the facilities on these topics, which we feel sure that fresh air can pass over them, and then at hand to obtain them. our readers will find a real treat. by means of suitable flues into the rooms There are at present four extensively 11 11.1111111111111111111111111111°1111. above. Once more it is essential that some used substances employed for heating: provision be made to keep the incoming the occupants. It should be borne in mind 1, Coal ; 2, Oil ; 3, Gas ; and 4, Electricity ; air moist, and this may be accomplished by and these will be taken up under the vari- that when insufficient air is admitted be- pans low the fire, more placing of water upon the steam coils ous systems utilizing them. Conveniences carbon monoxid will re- or radiators. If direct radiation is used, and disadvantages enter into the question sult, and the full heating value of the fuel will not be one disadvantage of this system of heating of selecting either of these. In houses coal obtained. is that the air in the room is dry. apparently holds its own as a favorite, Indirect Radiation. The ordinary hot air Water is used for heating on account of probably because once lighted and furnace represents this form of heating. with By this means its great capacity for retaining heat. The proper attention the fires may be kept in the air to be circulated is hot water can be carried thru the pipes to for considerable periods time, and also admitted thru a duct from the outside of of the some distance from the boiler, give up its on account of the number of rooms which building and passes over the heated heat and then be returned by means of an- may be heated by means of radiators or surface of the iron and is then distributed other series of pipes to the boiler. heated air systems. thru pipes to the rooms. Owing to the fact The Hot Water System has this advan- that the warm expanded air leaving a Ventilation is as important a factor in register tage over steam that as soon as the water heating rooms as the actual heating itself, can hold much more moisture than is warm enough to circulate it begins to and mention of this referred the cooler denser air that entered the heat- will be to ing passages warm the room and the heat is retained thruout this article with practical labora- of the furnace, it has a dry- for a long time after the fire has been tory experiments. allowed to die down. In the case of steam There are three common methods of there is no heat from the radiator till the heating, i. e., by means of 1, direct radia- water in the boiler is above the boiling tion; 2, indirect radiation; 3, direct -indi- point. With the use of hot water the tem- rect radiation. perature of the radiator is never above Direct Radiation. Under this heading 100° C. and usually much below this, and may be included the open fireplace, stoves with a suitable surface for evaporating or else by pipes or radiators carrying steam water in the rooms the air will be very or hot water. The open fireplace is not an agreeable. As the temperature of the economical method of heating, because it radiating surface is lower than in the case wastes from 75 to 95 per cent. of the fuel. of steam, the heating surface must be This form was utilized before boilers and fig. I much larger and consequently the cost of furnaces were introduced and are now used a installation is greater than the steam sys- in regions where the supply of wood is Fig. 1 -By Placing a Candle in an Ordinary tem. abundant and coal or other mediums non - Lamp Chimney Open at the Top and Fitting In, Close to the Table at the Bottom it Will Be the direct -indirect method of heating accessible. When heating by means of a Found That the Candle Will Soon Stop air is brought from the outside either be- stove, air being essential for combustion Burning. This Illustrates That the Fresh hind or below a steam or hot water radia- of fuel, it is thus removed from the room Cool Air Will Not Enter Freely at the Top. tor standing in the room, and is heated in Fig 2-If We Now Take a Chimney Closed at thru the chimney; consequently an equal the Top and Open at the Bottom and Once its passage over the radiator. This is also amount of fresh air must enter the room More Introduce the Burning Candle, the theoretically very satisfactory, as excellent to make up for that lost. When using a Candle Will Again Go out, Illustrating That ventilation is not the Warm Air Within Prevents the Fresh secured, tho often at- stove, it should be large enough to thoroly Air from Entering. tempted on a large scale. heat the room, even in the most severe Fig. 3-If We Now Take a Chimney Which In order to secure good ventilation the cold weather, without running at its fullest Is Open at Both Top and Bottom It Will fresh air introduced into the room must Continue to Burn.' The Cool Air Will enter heating capacity. It is false economy to Below and Drive the Warm (Less Dense) be ample in volume. It must be free from heat a room with a small radiating sur- Alr Out. contamination with dust and germs. 898 ELECTRICAL EXPERIMENTER January, 1920

THE CONSTRUCTOR'S

Nome CID mcle Searce By FRAHR CALVERTfl. STo . , ii `` I`- __ .g r a B ktl/olor l' A - Box 111111 A

D,Cor(wos 0 ° 1! ¡ C =PeadR eading g /ens fCorbori .. f f Supr) for bolder box.

I B fC o ; 6;Hood/e I _ n Door. . .

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9 1 , ' 4 A ., Fúses i . O 1' `

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At Right-the Constructional Details for Building a Home Made Arc Searchlight of 1,000 \ I to 1,200 C. P. It Is Operable i U '''\ on 110 Volts D. C. or A. C. _ - =-.5;2' Above-the Arc in Operation, With Rear Door Open. f

IPRESENT herewith plans of an arc trodes immersed in the solution thus made. made smaller or larger. The addition of a type searchlight which I have just built, The box was lined with asbestos. The door at the back of the box makes it easier and I hope fellow experimenters will be carbons are fastened to the blocks with to handle the arc. The search -light can be able to make use of them. strips of tin. The bottom carbon being built of pine and the principal dimensions stationary and the top one loose enough to The search -light is crude but will prove are given in the plans. It is easily built. It is permit adjustment. The lens was an old very interesting. I am enclosing a photo which was taken connected with 110 volts, in series with a reading glass. suitable resistance. We used a tin can We found that by moving the carbons at night -time with the door slightly open. filled with salt water, having two elec- backwards or forwards the beam can be This light will prove highly interesting. EllectrIlc GM5 Stove Lighter should be box can be made of %" white pine and a I believe every experimenter £X. /loaf Bross 30X 09 %4 able to construct this electric gas stove /lordrubber : ,- spnoç hinged door attached so that the inside lighter, as it is very simple to make, being hand/e can be accessible at all times. made of old or discarded parts of a tele- Bross The handle "H" in the drawing, should phone, a spark coil from an auto, a carved lac" be at least /" thick surrounding the wire hard rubber or Bakelite handle to replace inside, where the hand grasps it so as to the receiver, which with a sharp knife and insure safety against a shock while operat- sand -paper can be readily made, two dry ing it. A hole large enough for the wire cells, and a box of the dimensions given to slide thru, should be bored the entire in the drawing, to contain the above .men- length of the handle. A brass tack or tioned articles. screw can be inserted, after being soldered A suitable one -half inch spark coil can to wire leading from secondary in spark be obtained from an old auto, or probably coil. The other wire leading from sec- your friend or the local garage has one ondary should be grounded to gas stove to which can be obtained for the asking. The get a healthy spark, altho the handle wire receiver hook can be taken from any old should be sufficient. This device can be gas stove or any convenient telephone. There are always three con- óido Spit coil onm C0/70.' Bo/leery attached to the on the hook, but that will not inter- 5 ... place near the stove. tacts ALVIN WALSTAD. fere as long as only two are used. The A Useful Gas Stove Igniter. Contributed by January, 1920 ELECTRICAL EXPERIMENTER 899

v© v Ca k elt' OT ClIZT iP nn ® age V ztteTte,5 4 By LrLLLlio-nr WIiFSLtTE

ASMALL Tungar rectifier for charg- dimensions. The sizes of wire are : No. detailed above, and the projecting paper cut ing storage batteries from 110 -volt 10 D.C.C. or enameled for the 2 -volt fila- in with shears as far as the coil at each 60 -cycle alternating current re- ment winding to carry the curitnt of corner, then folded up over the outside of quires a General Electric Com- around 10 amperes, 8. turns being needed, the coil. The whole is then covered with pany's Tungar rectifier tube and friction tape, ordinary coil- winding tape, standard Edison base porcelain socket, and Ú Ú bO ÚG a step-down transformer giving 2 volts fer .E o> o m o8N ,Sawed e y b a ¿ô.-c .-. '; o.,w Brads Nail Brad Noi' ú &M1 Sowed a z3 z Í , ín záá á ú cc>ce oóó pc óÁ ac0 Uóóí F 1 " by 1 S.S. 62 & E83Ú Ell 550 75 10 1 I by 1" 4.5 495 154" 11/," 4 440 60 8 1W' TyH-y 1%" 3.5 385 53 7 4 " 330 45 6 1y," by 2 " 2.5 275 38 5

or 4 turns per volt ; No. 18 D.C.C. or enam- eled for the 15 -volt winding, to carry the 2- ampere charging current, 60 turns being required; and No. 20 D.C.C. or enameled .; to carry about 0.5 ampere for the 110 -volt How the Author's Complete Vacuum Bulb Detail View of Wooden Winding Form on winding to be connected to the power Which Transformer Coils Are Wound. The Rectifier for Battery Charging Appears. The 440 110 Size of the Apparatus Can be Judged by the supply, turns being required. The - Diagonal Split Allows of Removing the Core Rule at the Left. volt winding is on one leg, and the other From the Coil Easily. two windings together in one coil on the or cheap cotton tape 1/i" wide or more, the tube filament and 15 volts for charging. other leg. threaded thru the coil and over the out- The small tubes are made in two sizes, of The windings are in the form of coils side. This makes a neat and solid job. 2 and 5 amperes carrying capacity respec- wound on a wooden form, the core being The tape may then be further secured with tively. The outfit illustrated has a 2- ampere built up inside the coils afterward. Fig- shellac. gfieving should be slipt over the tube, costing a little over two dollars, and ure 2 shows the construction of the wind- leads before putting on the tape. One coil is suitable for charging storage batteries ing form, a block of either soft or hard consists long of 440 turns, the 110 -volt winding; at a low rate. wood 134" by 134" square and 2/" the other coil of the 60 -turn 15 -volt wind- The transformer, shown in Figure 1, has ing inside, with the 8 turns of large wire extreme dimensions of 5" by 51/a" by 23/4.", for the 2 -volt winding on the outside. The and is of the closed core type. The core sí" first coil will then have two leads, and the is 4" by 5" outside dimensions, with a 1/" second coil four, two of which may be by 2%" window and a cross -section of soldered together (the No. 10 wire being 1/" by 1/ ", built up of L- shaped stamp- left for the lead), as the 2 -volt and 15-volt ings. For 60 -cycle alternating current windings have one terminal in common (see and a flux of 60,000 lines, the trans- I in i diagram Fig. 3). former equation E = 4.44 4. f N X 10-8 After the coils are finished they may be 6.25 E, laid alongside of each other on a table, and the winding formula N - where the core built up inside of them. To make A this easy, they should first be lined with N is the number of turns required for a heavy cardboard or fiber, projecting %" given voltage E, and A is the area of cross - beyond them at each end. The core is built section of the core in square inches ; that ï up of ordinary transformer iron stampings is, the number of turns required for any 1/" wide, cut in L- shaped pieces 5" by winding is equal to six and a quarter times Fig.! 234", the short side of the L being 1/' the required voltage, divided by the cross in length (measuring from the inside edge sectional area of the core in square inches. Side and Top Views of Rectifier Transformer of the long side of the. L), to leave a win- Allowing for loss of area in stacking the dow 1/" wide by 2/" long, as shown in core, the following table shows the num- It should be cut 1/16" larger than 1g/ ", Fig. 1. Two of the L- shaped pieces form ber of turns required for the three wind- that is, about 1 11/16" to allow for the one layer. They abut, and, in the same ings for various sizes of core, so that ma- width of the saw cut which, made diag- layer, do not overlap ; therefore they should terial on hand may be used if desired. onally, divides it into two lengthwise wedge - not be placed tightly against each other, The 1/" by 1/" core was the one used shaped pieces, held together by brads dur- but a space of 1/16" or more should be left in the rectifier illustrated in the photo- ing the winding but easily removed from between abutting edges. These gaps may graph, and its construction will be de- the finished coils by extracting the brads be easily closed up afterwards with a ham- scribed. Other sizes of iron may be used and pulling out one of the parts. The mer ; but if they are put in tightly together equally well, with proper allowances in form may conveniently be placed between (Continued on page 958) centers in a lathe, with a nail projecting from one end to catch in a dog so that it will turn with the chuck, which may be rotated by hand. In making each of the two coils the form should first be wound with several layers of heavy paper, the ends of which are secured with shellac. This paper should be allowed to extend /" or more beyond the ends of the block, to be used later. The wire is then wound on in even layers 2 %" long, to the required number of turns. At the end of each layer the turns may be held from slipping off by 4 short pieces of friction tape, folded once around the end turn (one piece on each side), the tape ends laid back on the surface of the coil, and succeeding turns wound them Hook -up of the Single Tube Rectifier for over to Connections of Two -Bulb Apparatus for Fu Half -Wave Rectifications of A -C to D -C for make them fast. When the coil is complete Wave Rectification of A -C Into D -C. This Battery Charging, the form is removed from the center as Type Is the Most Satisfactory. 900 ELECTRICAL EXPERIMENTER January, 1920 0 rzton p ecrep l Instlrumment 5 y ï[110M 5 VT. ENS®N

THE experimenter usually has in his mark on the burette or graduate tube. possession electrical measuring in- The solution must first be saturated with struments of somewhat doubtful ac- oxyhydrogen gas. Connect the voltameter curacy. The checking of these is to a source of current allowing one ampere quite a problem when standards are to pass for a minute. The solution will rise not available but by the method described in the burette in direct proportion to the here it becomes practical to check their gas generated, but take care that it does not readings with a high degree of accuracy. flow over the top. Cut off the current and By making use of a voltameter we have gently shake the apparatus for several min- certain standards that can easily be con- utes. verted to our purposes, the more common A wad of absorbent cotton can be put in forms of this instrument being the silver, the top of the -burette or a short test tube copper and gas voltameters. The silver inverted over it to keep out the dust. After voltameter is unquestionably the most accu- each experiment the solution is returned to rate of the three but, like the copper, it zero by opening the pinch -cock on the rub- demands a sensitive balance to determine ber tube, allowing the gas to escape. This the amount of metal deposited. On the should be done carefully so no electrolyte other hand the gas voltameter requires but will be forced out of the tube. Fine adjust- the measurement of the volume of gas lib- ment of the column is obtained by the clip erated and since such measurement can be controlled by the knob on the front of the made with inexpensive pieces 3f apparatus instrument. Careful workmanship and neat this type was selected as the more suitable finish gives a very handsome instrument of for general application. value to every experimenter. A gas voltameter can be constructed as The instrument is now ready to be used shown in Fig. 1. A small glass bottle of as a standard for calibrating an ammeter. wide mouth and two and a half inches high It has been determined by experiment that is arranged to be mounted on a base which one ampere will liberate 0.1740 C. C. of oxy- supports an upright of wood one foot high hydrogen gas in one second or 10.44 C. C. and two inches wide. The cork for the in one minute. The instrument described bottle, which should be of rubber, has cut has a rating of nearly 60 coulombs, that is, in it four holes. Two holes take carbon it will measure current values to that electrodes obtained from small flashlight amount. The maximum current, however, Homemade batteries. These carbons are thoroly Calibrated Voltameter. It Is of should not exceed five amperes ; at this the Gas Type and Depends on the Measure- cleaned by boiling in water for fifteen min- ment of Gas Liberated. density the run should not exceed ten or utes to dissolve any soluble chemical that eleven seconds. may be in the pores of the carbon. Flexible applying vaseline and binding with silk leads six inches long are soldered to the thread will assure this. brass caps on the carbons before inserting A second rubber tube is slipt over the III other glass tube extending from the gen- Rheas-- erator. This passes thru a clip operated by Storage battery a knob on the front of the upright and is Voltmeter Ammeter arranged to be closed at the top by a screw Rheas. Storage battery pinch -cock. The adjusting clip is made from a strip of brass one -half inch wide and three inches long. Holes are drilled in the ends Voltmeter Ammeter and the strip doubled in half. An 8/32 nut 5w. is soldered over one hole, a long 8/32 bolt fitted with a knob passes thru the upright Fig, a 3W and one end of brass strip and threads into Circuit for Checking Voltmeter Utilizing a the nut. Turning the knob one way or the Standard Resistance, and a Voltmeter as other compresses or releases the tube. Well as Ammeter of Known Accuracy. Fig. 2 To set the apparatus up. Assemble as Hook -Up for Checking Ammeter With the shown in the illustration. From C. P. sul- To check an ammeter connect as shown Aid of the Voltameter (at Left). Ammeter to phuric acid and distilled water prepare suf- in Fig. 2. Two storage cells should be used Be Checked Is at Right of Circuit. ficient 10 per cent electrolyte to slightly to supply the current, a rheostat being in- more than fill the bottle. Open the pinch- serted in the circuit to limit the current. them in the rubber stopper. These leads to cock on the rubber tubing and pour the Close the circuit and adjust the rheostat till be connected to binding posts in the com- solution into the burette till the bottle is the ammeter reads one ampere. pleted instrument. just full then close the pinch -cock. Pour Open the circuit and bring the solution Two glass tubes are put into the other in more electrolyte till it reaches the zero in the voltameter to zero by opening the holes, one reaching to within one -quarter pinch-cock till it drops to zero. Final regu- inch of the bottom of the bottle, the other a lation is obtained by turning the knob on being flush with the bottom of the cork, the adjusting clamp, thus compressing or both tubes extending one -half inch above releasing the tube, causing the column in the top of the cork. Mr the burette to rise or fall as necessary. The cork can then be fitted tightly into Now, with a watch in one hand, close the the bottle and sealed by painting the top of switch when the second hand reaches 60, the bottle and cork with sealing wax dis- note on a sheet the reading of the am- solved in alcohol. The result is an air -tight meter and open the circuit after 50 sec- seal, a necessity if the work is to be accu- 111111M Min onds. Read the C. C. of gas evolved di- rate. rectly from the level of the column in the This completes the apparatus for gener- burette, the actual amperes in the circuit ating the gas, it remains to arrange some being obtained by the formula : method for measuring it. The most suitable G instrument is a Mohr burette of 10 C. C. I= capacity graduated to read .05 C. C. This .174XS can be purchased for 75 cents. Two clips Where 7 I I S are fastened to the upright to hold the bu- Actual turren/ vo/ue., G- C. C. of gas evolved as indicated by rette. A hole is drilled in the upright four Fig. 3 rise of solution in burette. inches from the bottom to pass the rubber S'= Seconds circuit is closed. tube connecting the burette with the gas .174= C: C. of gas evolved per second per Correction Chart for Checking Up and Cali- generator. The joints formed by the rub- brating Ammeter. Chart Shows Meter Read- ampere. ber and glass tubes must be perfectly tight, ing 10 Per Cent High. (Continued on page 958) January, 1920 ELECTRICAL EXPERIMENTER 901 llnahroment TOT MCMOoT Illg l°3ncQ1Ilo°ActIlvIlty By EVAN CRAWFoRD THERE are many ways of measuring A round hole is bored in the end of this the Radio -activity of various sub- support. One end of a round brass rod stances, and perhaps the best is by about an inch and a half long, well smoothed means of the gold -leaf electroscope. and rounded, is inserted in this hole. The The author has described this meth - hole is now filled with melted sulfur, which of measurement in the January, 1919, when cold insulates this rod from the sup- issue of this journal. Do not think, how- port. This is very important. ever, that this is the only method which In order to charge this brass rod from will give good results. The instrument the outside, a charger is arranged in the which is described in this article is a com- side of the case. A round hole about half bination of a torsion balance and an elec- an inch in diameter is cut in one side of troscope. With some care very accurate the case, and a No. 14 copper wire past measurements can be made. thru this. Melted sulfur is now poured The torsion balance as devised by Cou- into this hole. The wire is bent as indi- lomb consisted primarily of a non- conduct- cated in the illustration, and in this manner ing rod, having a small piece of metal on the brass rod may be charged from the one end, suspended by means of a fine outside. ' In the other side of the case a metal wire. A glass rod is arranged so as round brass tube is placed in order to intro- to have one end in the vicinity of the end duce radio -active substances into the case. of the non -conducting rod. When the glass This is accomplisht by means of glass tubes rod is charged it attracts the metal on the and slides. end of the rod, and the force thus exerted The movement of the glass slip is viewed is measured by the torsion exerted on the by the use of apparatus illustrated in Fig. wire. Using this apparatus Coulomb, estab- 2. A long cardboard scale is placed about lisht the following laws of electrical action : a foot away from the case, having a slip 1. The repulsions or attractions between cut in the center. A light placed behind two electrified bodies are in inverse ratio this slit sends a beam of light to the glass to the squares of their distance. slip, from which it is reflected back to the 2. The distance remaining the same, the scale. The movement of the slip is thus force of attraction or repulsion between greatly magnified on the scale. two electrified bodies is directly as the The instrument is used as follows : The product of the quantities of electricity with round brass rod is charged by turning the which they are charged. i. B/och composition *nob. 2: Hair 3.- Bass r»nd. charging wire so that it makes contact with It will be found that these laws affect 4 Thin glass slip. S- NYeeht ó- Su/phurinsa/o /ion same, and then applying an electrified hard the working of the instrument which will 7 Sulphurimsulotion. B- Charging rod. 9 -Tube rubber rod to the outside end. The wire now be discust. For this attraction works Rr/n/roduc /ion a/ac / /ve ramáaunds._ is then turned away by means of the also between two bodies, one charged and charged rod so as not to discharge the rod. the other supposed to be uncharged. For The hard rubber knob on the top is now a more detailed account of the action of adjusted so that the reflection from the scale. the torsion balance, the reader is referred Source itorogiry glass slip is in the center of the to any good physics text -book. of /fight gloss 51/11 This means, then, that the attraction of the The construction of this instrument, round brass rod for the gold leaf on the which we shall call the "Torsion Electro- glass slip is exactly counterbalanced by scope," is illustrated in Fig. 1. The case is the torsion of the hair. When a radio- made of half inch oak, 12 incls in height, active substance is now introduced into the 5 inches broad, and 4 inches deep. The case, the air is ionized by the rays, and the front of this case is a piece of ordinary fig. 2 round brass rod slowly loses its charge. window glass, which is held by means of This allows the torsion of the hair to turn spring clips. In the top of the case a small The Reflected Light Ray System of the the slip, which movement is seen on the hole is cut, over which a brass strip is Radioscope. scale. The speed with which the reflection fastened. A spring clip or binding post is tached to the hair about an inch above the passes over a set number of divisions on attached to this, thru which a round brass weight. This slip is formed by cutting in the scale is a measure of the radio -activity rod passes, having a hard rubber knob two a thin square cover glass, such as is of the substance. By this means, then, the mounted on the upper end. The torsion used in microscopical work. A small piece radio- activity of substances can be accu- portion is attached to the lower end of this of gold leaf is now attached to one end of rately measured by watching the spot of rod by means of a drop of sealing wax. this glass slip, which in turn is attached to light on the scale. This permits easy adjustment of the torsion the hair by using a dab of sealing wax. There are many other uses to which this element of this instrument. A wood support about three inches long instrument may be put, such as the mea- This torsion element is constructed as is now fastened to the back of the case surement of the ionization caused by follows : A small lead weight is attached about three -quarters of an inch below the X -rays, ultra -violet rays, incandescent to one end of a silk fiber or hair, the other glass slip. The correct position for this metals, et cetera, and it would be a useful end of which is attached to the adjustable support can only be found by direct experi- acquisition for any Amateur Physicist's knob in the top. A small glass slip is at- ment, as it varies on different instruments. laboratory. Wire Terminals from Socket 5heRis IlcycIle.Lamp rum Old Here is a drawing and description of a This light can be made from an old elec- Good wire terminals can be made by se- and reflector, to- curing copper rifle or revolver shells and simple bicycle or trouble lamp. tric light key socket the placing them in a vise so as to flatten the gether with the glass from a small two -cell cap ends. The holes can then be drilled tubular flashlight. The reflector is soldered easily. See illustration herewith. inside of the socket in such a manner that Contributed by RAYMOND DUSSEL. it does not short -circuit it, but when a it, will make unatavtaNmxmm flashlight bulb is screwed in it f/O//ened a good connection with the center terminal. The glass is now filed around the edge until ..uvINMIFrnIIIIIIn.fyRfllll s! it is a tight fit for the small end of the .mmmlwwmlae u IlIIIiI socket case. But be sure it is in good and lllIli not be knocked out Dril/ ho/B ugU11W RWpP\\\\\ tight so that it will cc 3 when the light is carried around. This /der/eadinhefm makes a useful light for a bicycle or a trouble light for a car. Good Wire Terminals or Lugs Can Be Fash- How to Construct a Bicycle -Lamp from a ioned from Copper Rifle Shells. Discarded Socket. Contributed by CHAS. M. QUEEN. 902 ELECTRICAL EXPERIMENTER January, 1920 SeLecflve 5wHich TOT Th.rf©© ©T M© llnIeTph©neo

Having occasion to use three of the ordi- simply made up of parts obtainable at any the 'phone to wire No. 5. Connect switch- nary Interphones, such as are used on lines electrical supply house. This switch is nor- blade to new wire and also connect new up to 500 feet in length, I found they were mally kept at the right, on dead contact switch contacts to this wire. Other con- point. nections are made in duplicate of those in When the user wishes to call a station, sketch. he moves the switch blade to the point cor- Contributed by RAYMOND A. RAN - responding to the number of the station he SOME.

Phone 3

IIIIIIIII

Common return

A 4- Station Inter -Communicating Telephone System Employing Simple Battery Instruments, Converted to Multiple Station Types as Shown in Drawing at Left. A Battery Is Used at Each Telephone, the Ringing Buttons Being on the Instruments Themselves. is calling. The 'phone is then employed [Ed. Note: It is usually found in prac- in the usual way. Upon finishing the mes- tice that more satisfactory results are ob- Making an Inter -Communicating Telephone sage, the handle H must be turned so that tained if the "home line" connection "X" is From a Common Battery Type Instrument. switch -blade B is on dead contact, or as A Switch and Base Board Are the Only made to the "home point" on the switch in- Extra far to right as it will go. Parts. This system takes care of as many stead of directly to the switch-blade as here only intended to be used between two sta- 'phones as desired: If the user wishes to shown by the full line. Otherwise, when tions. connect another 'phone, he needs only to two parties are talking, for instance Nos. 1 The solution is in the selective switch and run one additional wire and add one con- and 3, then party No. 2 or 4 can ring in wiring diagram illustrated. The switch is tact to each switch. Connect one side of your ear or cause interference.] . Home Macóe EL©cTfic Er©ri

Here's how to convert your sad iron into an end of the wire at each side. By care- The connection block is made of tran- a glad iron. This is an electric iron that fully following the drawing there should site or asbestos board. A connection plug any amateur electrician can make. It is be no trouble in constructing it. A layer may either be bought or made. If you have useful, cheap and can stand a great deal of mica is put on both sides for insulation. an electric appliance with a plug on it a of use and abuse. Its construction is The bottom plate is made of cold rolled very good idea is to use it for both, such simple, and the parts easy to obtain. The steel and . cut out the shape of the iron. as I have done. The distance, therefore, drawing will explain the iron fully. The To conserve the heat there should be a between the plugs on the connection block iron is an ordinary flat -iron fixt up as piece of thin asbestos of the proper thick- depends on the plug used. shown in the drawing. ness placed around the edge between the The cap screw should be tightened up The nichrome resistance wire for the top and bottom of the iron, indicated at real snugly and the bottom filed flush. It element may be obtained from an electri- XX. should then be smoothed and polished. The cal supply dealer by iron is now ready getting him to save for use. the old elements he Such an electric takes out of the sad iron will prove standard electric a boon to mother irons fof you The and the girls and nichrome wire re- you will gain their ferred to in the everlasting gratitude drawing was ob- by giving them such tained from a West- a convenience -in- inghouse heating el- deed a necessity, to- ement. The mate- day. The longer rial was 1/16" rib- the ribbon, the high- bon nichrome. New er its resistance and elements for irons the lower the cur- may be bought, but rent as well as the are somewhat ex- heat produced. pensive. The wire Contributed by is unwound and flat- PAUL tened out. It is LIFSCHITZ. wound on 1/32" [Editor's Note: - mica cut out as per On receipt of stamp- drawing. In rewind- ed, addrest envelope, ing, care should be names of concerns taken to follow the supplying suitable drawing closely as resistance ribbons and wires will be it is very puzzling A Good Design of Home Built Electric Sad Iron. The Resistance Wire Is Wound on a Mica at first to bring out Sheet as Indicated. furnished gratis.] January, 1920 ELECTRICAL EXPERIMENTER 903 ,cctr isGc'a, ElEchl'nist By WEN .PBEj( D SIE,C®Ii3 or dreds of armatures have been saved in this. No. 3-Motor Journals and Bearings. The bearing itself is usually of brass phospor bronze, preferably the latter, and way from the scrap pile in several large IN the repairing of electric motors and are used in all repair shops with which the writer has dynamos, particularly in the smaller phospor bronze bearings size of motors and dynamos, and other been connected, and a first class job is in- sizes, and a great deal of which is one of the variably the result. At this point it should in the electrical machine machinery, it having proved encountered very best metals for this purpose. be mentioned that the armature must be and repair shop, there are a number watched very carefully while machining the of interesting wrinkles which we will con- Many motors and dynamos above / to horsepower are provided with babbitt Shop, cutaway BrassarBranre loch scnswa nut metal bearings, and several makes of even /i; lathe bearing), the larger size machines are provided with 'Z'S(/,1&102Z/7.Z. steel and cast iron bearing sleeves, held in y the bearing proper by babbitt metal, as 7/I7l/7l/771U11 -=t i IiTww`à shown in Fig. 3. ourva/ -A- Stee/ bushing Anlrsp/ash In repairing machines in general, it is groove usual to try and purchase a new bearing from the manufacturer or from a supply house dealing in these parts, which often saves considerable time and makes a far ',Sterner better job all around. Fan bearings are w/ cup usually procurablé from any fan supply - dealer or else from the manufacturer of - - felt eiert Cup.' the fan, whose name appears on the name finis/kd plate thereon, invariably. The amount of JouMo/. Wich spring - fasehhe orhea easily judged at play in the shaft can be fig. 2 CE Fig. , fir any time by taking hold of the commutator or the end of the shaft, by working it first Showing How a Badly Cut Shaft Was Re- Typical Small Size Motor Bearing, Fitted sidewise and then up and down, and ver- bushed so as to . Fit Standard Size Bearing. With Wick Oiling System, Grease Cups, etc. tically. If this motion exceeds 1/32 of an inch in the smaller machines it is not shaft in this manner, so that the tool car- sider -here. At figure 1, is shown a typical usually permissible to let this pass, and a riage, etc., should not touch the armature small size motor bearing with its oil feed new bearing should be substituted or else and damage the winding. A trick of the cup of the wick type. This type of bearing a relined one, more about which will be electrical machinist in connection with this is used on many different makes, of elec- said anon. work is one which, while fraught with the tric motors of %oto V8 H.P. It is also used the winding and all electric fan motors. This danger of short -circuiting on practically REBUSHING WORN SHAFTS. the oil cup and bearing design is simple and necessitating the entire rewinding of is to turn down or file very care- time has shown that it is thoroly satisfac- It is not always the bearing that wears, armature, tory for small and medium size bearings. however, as in some cases the shaft, par- fully, the surface of the armature drum. done when after a repair The brass cup is threaded onto a shoul- ticularly if it is a very mild or soft steel, This is sometimes der provided with a threaded stem which fits will "cut" until it . is filled with grooves, job of this or similar character, the arma- up into the bearing in the manner shown. even to the point where it resembles a ture is slightly out of center, and comes The cup is usually filled with a cheap grade machine screw. Of course it is foolish to too close to the pole -pieces of the machine. of vaseline or else heavy machine oil. The place a new bearing or bearings in a ma- As before mentioned, it is hardly to be lubricant is fed to the bearing by capillary chine in which the shaft is \worn to such recommended, but as this has been done attraction thru the wick, and the wick is an extent. many times in electrical repair shops, it prest'against the journal of the shaft re- Some electrical machinists follow the is mentioned here for what it is worth, volving in the bearing, by the wick spring, easiest road in such a case and simply take and providing the laminations of the arma- -this spring being clamped or riveted a pair of somewhat smaller bearings and thru a hole, or otherwise, onto the wick, turn down the shaft to fit it, thus obtaining (Continued on page 952) so as to maintain steady pressure upward a new and smooth cylindrical surface on on this member. the shaft. This is sometimes permissible, setscrew ho% Babb/i Poor hefe /S/afi housing is, in the better but usually it is unsatisfactory for the rea- mela/ 1 The bearing c i -c class of motors, carefully designed with son that the designer of the machine made the shaft of its original diameter so that 'Aareidarafef Woo.; it would not heat up on long runs, etc. Therefore the original size of the shaft should be retained whenever possible, and .,,,e e;,/,ftträ, íl it is the standard rule in all first class hole /bra/ electrical repair shops, to maintain this -A- wich practise. Pourhot hobbit Wooden plug 1III Figure 2 shows how such a worn shaft /n here Shaft or fire cloy, with a steel is "rebushed," in this case, ma' &sbeslos, \ of/riiy so /s1 sleeve shrunk onto a turned down journal. of/ /evel- At figure A, the worn journal is shown -.p-.>, imialñ ?ydb tboíd clearly and also the part which is to be cut away in the lathe. Bross shelf Of/gruves, Sritgte á/ ring s /e, By means of inside and outside calipers, Trbned beoriag s/eere the reduced portion of the journal is ma- made of bronze brass chined with a diamond -point shaped tool, steel ar /rzan pipe. until it is of the same diameter as the in- -Plug side bore of the bushing, finishing the turned down shoulder as smooth as pos- freeloy all around sible and touching it up a bit with a fine - hearthg is then ex- cut file. The steel bushing Leather panded so as to be driven onto the stem 'ha/der Fig. 4 without too much pressure, by heating it cherry red in a gas or other flame. How Rebabblted Bearings are Grooved to driven Journal. From 01 Fig. 2 -B shows the steel bushing Distribute Oil to Shaft it is Rings. into place on the journal, and then Se/uefrmnm /ng ladles allowed to cool. Provided the fit has been fig. 3 EE properly made, it will be held very firmly oil retaining rings or anti -splash grooves in Rebabbiting Bear- in event on the shaft. The new journal is then Various Steps Followed on both front and back, so that the -New Self- Skimming Lad- is fed to the bearing, turned down, to the proper size to fit in the ings. At Bottom that too much oil les and Leather Holders for Ladles. it will not be thrown out. original bearing as shown in Fig. C. Hun- 4 904 ELECTRICAL EXPERIMENTER January, 1920

HOW -TO- MAKE -IT

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

FIRST PRIZE, $3.00 SECOND PRIZE, $2.00 THIRD PRIZE, $1.00 USING MAGNETO ON TOY A HIGH -POWER PHOTO PRINTER THE SIMPLEST BELL-WORKS BY TRANSFORMER. OF TRIED DESIGN GRAVITY. An inexpensive source of current for our Herewith is a sketch of a Having been ELECTRICAL gravity -oper- young Experimenters can easily be ob- a reader of Ex- ated bell which I have made. PERIMENTER for some time, being an engi- neer by profession, also a hobby rider, the gallery writer is taking the liberty of submitting Thls bar fits snugly into the to this Department a device which it is brass collar so that,,'rnoves thought many people inclined to do photo- abat tradey and canp/eles graphic printing will appreciate. the circuit when necessary The accompanying sketch explains the device in detail. It is designed from one which was constructed from shop odds -and-

ends, and has for some time been doing ; continuous daily service in one of the Gov- ernment photographic laboratories at Wash- :fit" ington, D. C. ironia Electra-magnet Brau co %hi Wiring Diagram t - Lamp ,.' WOO.....-.r.-.. F _.,..._, ...... F Bush/ A Clever Stunt -Using the Magneto on a (insulating 1-- Step -Down Transformer for Ringing Bells, C R.m------r-, --r Tg.r 3 Operating Small Motors, Etc. -I; B 'Reducer-----

tained with the following apparatus : A Very Simple Form of Electric Bell -the CIr- 110-volt telephone cult Is Made and Broken by the Rise and magneto generator, and Fall a toy step -down transformer are all that of the Hammer by Gravity. is necessary. The plug should be removed ¡ /S Bridge the The simplicity of this bell enables any- from the transformer and the wires con- SF/oor flange] two front body to make one for his own use. It nected to the magneto /1 ITee consists of an electro- magnet, as shown in diagram. 1 mountedonwa/I 1 1 jaws of an iron bolt - The magneto may be operated by crank switch head or bar (which is able to slide readily handle or attached to sewing machine, thru a brass collar) and a brass bell or gong. water motor, or other surplus power. The /ron pipe *xp iegbo/t current obtained from the terminals when When the circuit is closed the magnet the magneto is run at a is energized and attracts the iron moderate rate of xl Burhing. core. speed, is strong enough to ring bells, oper- 4 This opens the circuit as the core is pulled ate buzzers, etc., and should prove very Reinforced /amp cord , away from the gong; and the weight of useful when a small amount of current is the hammer forces it down upon the bell, 'required. Mogul /amp soufrtf4 thus completing the circuit once more. Contributed by JOHN P. SORENSEN. cap -- -- This action is continuous. This type of i bell does not necessitate a spring. Sheet meta/ i Contributed by MANUEL E. SPRING. A TEA -KETTLE ALARM. shade -- Now that the winter days are here, :1,;- /0' LAMP RECEPTACLE A HANDY the housewife will be anxious to have Type "C'Mazda /am MATCH HOLDER. a kettle alarm undoubtedly, one that will A match holder may easily be made from Extra long tell her when the water is boiling, instead Printing frame, the porcelain portion of a discarded electric of having to wait in the kitchen to ascer- handle - light receptacle. A piece of cigar box or tain this fact. This electric alarm device other wood may be fastened to the bottom should be of convenience to her. The by means of screws. A piece of sand- paper may be glued aluminum which is heated by the hot steam Double po/e Sing /e throw, 30Amp. knife to the side if desired expands thereby making switch. Contributed by ALTON D. SPENCER. a circuit which Switch moonLed o. i under rings the bell. ride ofshe/f aworkbench. Contributed by GARRETT WOLPERT A Rapid Photo -Printer Which Has Been Tried by the Author. Printing machines, boxes and other de- vices have their advantages, but this de- vice is possest of a number of valuable features. Some features : Inexpensive to make; readily adjustable; very little maintenance required ; simple to operate; has maximum factor of safety; all forms of "dodging" and "shading" printing readily performed; if desired medium lamp socket may be used in place of Mogul socket and intensity of printing light easily varied by changing various sizes of light bulbs or an adapter When the Steam From the Tea Kettle may be used in the Mogul socket to ac- Ex commodate bulbs with medium -sized panda the Metal Strips, They Touch and bases. Porcelain Lamp Receptacle Serves Close the Alarm Bell Circuit. Contributed by C. A. PURDY. as an Ef fective Match Holder. 1 January, 1920 ELECTRICAL EXPERIMENTER 905

rip. kl- s ,=,12`, ll i*1 I_lwl yTM.'a[ i, ÿrlL I . . ' , r_ , ,?_ ./_ ula;%1;'; ! ; 41a,., ! . .' n VW4l 1h I H! 4,4 EDITED BY S. GERNSBACK

SILVER PLATING the object to be plated at the cathode, close The first indication . SCIENTIFICALLY of a change of state DONE. the switch and allow a current of 2 am- is the disappearance of the meniscus (tilt' Silver plating by electrolysis, the amateur peres to flow for 30 seconds. upper curved surface of a liquid), immedi- usually finds a difficult operation. But this Then remove the work and rub with very ately following this flickering striae appear, is because he does not know and observe fine sand to determine whether the silver unrest pervades the tube, and then the the necessary precautions. In electroplat- is depositing evenly. If it is not, repeat the liquid has become a gas. whole process, starting ing of all kinds the prime consideration is with the first clean- Contributed by ERNEST absolute cleanliness. ing solution and ending with the electro- LINDER. lytic Set up your plating bath as shown in the deposition of silver having as before a current of 2 NOVEL DRYING TUBE FOR GAS diagram, using about, 8 gravity cells or 4 amperes. GENERATOR storage cells. An ammeter connected as Now cut out all but one cell and with a shown is highly desirable. A solid silver current of about 3/10 of an ampere con- Large or medium size test tubes break anode about the size of tinue the process until the requisite thick- quite frequently, and these tubes may be a quarter must be ness suspended at the positive pole and the ob- of silver has been deposited. put to good use by making drying tubes ject to be plated at the cathode or negative Remove the object, rinse in water, bur- nish and buff it. Rubbing funse/ pole. with rouge - 1r6v'af Drying First polish the object to be plated after red oxide of iron -is the best method of CottOt \ buffing. Cost basten /es/ /ue ck Cork In using cyanides exercise the utmost s care. Do not inhale cyanide fumes, for 1rrsµ L.- they are poisonous. RuDLV2Da Contributed by FLOYD L. DARROW. '-Coat CoC/1 0/ive ball/e THE CRITICAL STATE OF I MATTER. how to cut lróhdltst lode When Croched dot Ian a gas is at the critical temperature of tube and at the critical pressure also, the in- crease of pressure or decrease of tempera- ture will convert it into a liquid. When in z,./tofor/t, this condition a gas is said to be in its 04 0, /.OrC4 B- critical state. S.hClfcrN,3, G,.#At= Imo The phenomena of the critical state can u be beautifully shown as follows :- Select a test Diagram Showing How to Set Up the Silver- tube at least 8 in. in length and 1 in. plating in diameter. This should Outfit. be filled with Gas Should Be as Dry as Possible. This In paraffine. Also procure a glass tube about expensive Gas Dryer Should Be Welcome In which remove the grease that will surely Every Laboratory. adhere to it by dipping in water and then for a half minute in a cleaning solution from them. This is done by cutting off made as follows: the cracked part (B). Procure two corks Caustic soda 100 grams to fit the ends, each having a hole thru Water (preferably distilled) 1000 c.c. which a small straight or curved piece of The temperature of this solution should be tubing passes. (A). Insert one of the about 40 degrees Centigrade, or 104 degrees corks, and on top of this a small wad of Fahrenheit. Remove the object, rinse in cotton. Then fill the tube with calcium clear water and then to remove certain chloride, leaving enough room for another oxides that still remain on the surface dip wad of cotton and the other cork. This for a half minute in the following solution: dries the gases very well. Potassium cyanide (very poisonous) The generator can be made from a small olive 25 grams bottle. (A). Bore two holes in its Water (preferably distilled) 1000 c.c. cork, and in one insert a funnel tube, thru After removing from this solution rinse as the other a delivery tube. This apparatus before in clear water and -avoid thruout when made costs practically nothing. Even handling with the (fingers, which will again the funnel can be made from glass tubing, leave grease upon the surface. with a little care. Now to roughen the surface so the silver If it is charged with hydrochloric acid will get a firm grasp place the object for (or sulfuric) and zinc; hydrogen is gen- a few seconds in the following solution: erated, and is freed from moisture on pass- Mercury (dissolved in dilute nitric acid) ing thru the drying tube. It is then good for the marsh 1 gram gas test, it being necessary Water 2000 c.c. to have the gas dried for this test If Then quickly rinse in about 2 quarts of charged with calcium carbonat or marble, clean water. and hydrochloric acid, carbon dioxid is The plating bath itself is made generated. If iron sulfid and hydrochloric as fol- acid lows : Dissolve 56 grams of silver nitrate are placed in it, hydrogen sulfid is in a small volume of water and likewise produced, and this apparatus can be util- 50 grams of common table salt in another ized for making nitrous oxid by charging equal volume of water. Mix the two solu- It it with scrap copper and dilute nitric acid. Of course, separate tions and white silver chloride will precip- A Fine Experiment to Demonstrate the Criti- ones can be made for itate. Filter this precipitate in the ordi- cal State of Matter. Caution! Use Wire each gas, which would be better, as the nary way with Netting Over Your Gas Flame When Sealing material is not very expensive. funnel and filter paper, or Ether Tube. Very Inflammable. better still thru clean unbleached muslin. Contributed by Wash the residue left on the filter by pour- 4 in. long and 5 mm. EDWARD MARENZANA. ing water thru it. outside diameter. Seal one end by holding in a flame. Fill one - Then make another solution of 225 grams half full with ether, of potassium cyanide and seal other end CEMENT TO MEND LEAKY in 1600 c.c. of water with blowpipe. The paraffine is now melted BOILERS. and in this solution dissolve the residue of by holding test tube in flame, and the small Powdered litharge, 2 parts, silver chloride from the previous operation. tube suspended in it very fine sand by means of a wire, 2 parts, slaked quick lime, 1 Heat the plating solution to about 45 de- as shown in illustration. part. Mix all grees Centigrade On continuing to together. To use, mix the proper quantity or 113 degrees Fahrenheit heat the wax the ether will go and place in the plating jar. Having placed thru the with boiled linseed oil and apply quick. It critical state. gets hard very soon.

possible to evolve the 1 op 3ov aegrees Illustrating the rave--zenynr- yr ..-....- with ease. Contrary to popular belief the Wave, or Oscillation. say, it is loop is not exposed outside of the compass grounded copper netting. This precaution house. Instead, and as will be noted from shacks along the coast are even remotely is necessary in order that possible stray the accompanying figure, the loop is in- associated with radio work. external oscillations be warded off from closed within the house and thus protected The receiving apparatus which accom- the receiver, otherwise these undersirable from the elements. The house or cabin is panies the loop is situated in the lower currents would influence the receiving ap- other non -mag- part of the room and consists of a special y paratus and render loop bearings inac- built entirely of wood and curate. Pivot Fig. 6 is a schematic circuit diagram of the radio compass. It will be noted that no ground circuit is employed and that the Revotub/e radio loop leads are connected directly to the 1 compass co// loading coil of the secondary inductance, RECE/VER AMPL/F/E.e instead of the primary, as is customary in other receiving circuits. No use is made of the primary ; the loop circuit being a direct -coupled one. THEORY OF OPERATION. In order to properly understand how the radio compass functions, it is perhaps not untimely to explain a few fundamental facts concerning its theory. To begin with, one may as well be re- minded that present day investigators have decided that the radiated oscillations from Coi/ (ostra/ any radio transmitter travel over the earth's whee/ surface in undulating waves having a broad flat front; in other words sine waves, similiar to alternating currents, shown in Graduo/ed WC dio/ Fig. 2. The distance from A to B is equal to the actual wavelength of that partic- Loase ular transmitter, which in this case we as- Pivot - mup/er sume to be 600 meters. Now if the plane of the loop windings is set to wave The Connections Used In U. S. Naval "Radio Compass" Stations. The Details of the at right angles the advancing Loop Antenna Are Given In the Text. (Continued on page 949) January, 1920 906 ELECTRICAL EXPERIMENTER

RADIO DEPARTMENT he RExclto o E50 y PIIIERRE EI. B®UC c(EROH9 Ensg:., cni U. S. Ho Ro F. IIt and receiving "radio- goniometers." The re- IN the bewildering maze of inventions What. B4 Bs -What ceiving goniometer was later modified and and discoveries which have been de- at the years Et Does Et -. adopted by the Marconi Co., and veloped during the very short Does-How beginning of the war was considered the following the entry of the United Ma Res Use ®f Et radio compass War, there Who most developed and accurate States into the World fool -proof. of the day. It took a war to bring the de- stands out an instrument which has the the navigation of ships almost

908 ELECTRICAL EXPERIMENTER January, 1920 An. 00 5cIlliIlon IR.aclio TeLephone and TeLeglraph This may be done when it is installed and once these adjustments have been made it will need no further attention. Absolutely no knowledge of radio telephony is neces- sary to successfully operate the set, and the non -technical man can run it just as well as the most up to date radio engi- neer. It is as simple in operation as the ordinary house telephone. One of the advantages of this radio tele- phone which will be duly appreciated by those who have had experience with the older types is the remote control system, by which the antenna is automatically con- nected to either the transmitter or receiver, by merely pushing a button. The telephone is designed primarily for 200 meter transmission, but sets can be made to operate on other wavelengths when desired. One 6-volt storage battery is needed in connection with the telephone to operate the microphone and the remote control relay. Any standard storage bat- tery will be satisfactory for this work. Us- ing this radio telephone in conjunction with standard receiving equipment ranges of ten miles and over may be reliably covered with a moderate sized The antenna. New De Forest Radio Phone, So Simple That a Child Can Operate It. It Works on The panel on which the apparatus is A. C., Thanks to the Two Rectifier Tubes Seen at the Bottom of the Apparatus at the Left. Just Press a Button and Talk-More Simple Than the Regular Telephone, Eh? mounted is of Bakelite 14x20 inches. It sets_ on an oak base 14x15 inches so that ALTHO the A. C. Oscillion Radiophone of the instrument is quite simple. All that the complete set occupies a minimum of Transmitter is something entirely new is necessary is to connect the power leads space. At the top of the panel is mounted on the radio market, it has been so of the set to the ordinary house lighting a microphone transmitter of the usual type carefully designed and constructed that it circuit, connect antenna and ground to the on an arm, to the right and left of which is claimed to be a practical instrument terminals of the set, push a button and is located the plate circuit milliameter which may be relied upon to give excellent talk. and the filament ammeters respectively. sérvice over short ranges. The operation The set needs to be adjusted but once. (Continued on page 954) New Undamped RacIlo ReceIlver'

Have you enjoyed the thrill of listening discharge. The telephone battery to the piercing whistle of the numerous un- is enclosed in the cabinet and has In the Photograph Below Are Seen damped wave stations now operating here a pressure of 40 volts, which can Two Pieces of Newly Developed Radio and abroad? Apparatus Which Are Well, the pleasure is all finely adjusted by the 19-point Unique in De- yours, especially so as the number be sign and Construction, Having for of sta- high voltage switch. Their Objects Maximum Efficiency and tions using this method of transmission Reception of Both Damped and Un- is increasing yearly, already all the Gov- To renew the batteries it is only damped wave signals. A minimum ernment land necessary to remove several screws Table Space Is Required. The Vacuum stations of importance are Tube Detector and Oscillator Is of the equipped for sending and receiving, while on the panel and base, thereby dis- Tubular placing the cabinet and making re- Type. all the battleships are . equipped for re- ceiving, their transmitters being installed newal easily accomplished. All con- as quickly as time will allow. necting posts are clearly marked The tone in white letters, these being en- of the undamped signals can be graved in the panel. The oscillat- varied from the lowest known to inaudi- ing inductance is machine bility; it is therefore possible to select any . wound with enameled wire pitch best suited for receiving. This phe- fitted nomenon is on a substantial tube indeed interesting and in strong with a positive contact contrast to the spark method whose tone switch, which allows of suf- is fixt. ficiently fine variation. The A glance at the illustration will disclose entire set is furnished in a the advantages of the vertical mounting mahogany -finished cabinet, over the cumbersome horizontal method all metal parts being nick- which occupies unnecessary space on the eled. The height of the ap- operating table, besides being harder to operate. paratus is 32 inches. The principle is regenerative in action, Loose couplers have from resulting in amplification. In its construc- time to time demonstrated tion a high grade of insulating material is their efficiency in being able used upon which are mounted all the metal to tune out all those stations parts carrying the oscillating currents. The not desired and allowing windings are machine wound with enameled those which the operator in- wire on substantial tubes. The compound tends to receive from to switch permits fine adjustment on the pri- come in with marked clar- mary inductance. The counter -balanced ity and intensity. Many have secondary is a unique feature which elimi- raised objections to their nates all difficulty in tuning, instantly re- use, however, stating that sponding to the slightest touch and re- they were inefficient because maining in any position. The balanc- of their coupling, but very ing weight is contained in the long brass few have been able to pro- tube which permits the secondary to be duce other apparatus to re- loose -coupled six inches, resulting in highly place them, and which selective tuning. would be so univer- The set has a wave length range up to sally accepted "the 18,000 meters on a moderate size antenna. best ever." So it The detector is of the panel type, using stands to reason that the tubular bulb producing a pure electron they are to remain. January, 1920 ELECTRICAL EXPERIMENTER 905

EDITED BY S. GERNSBACK

SILVER PLATING the object to be plated at the cathode, close The first indication of a change of state . SCIENTIFICALLY DONE. the switch and allow a current of 2 am- is the disappearance of the meniscus (the peres to flow for 30 seconds. upper curved surface of a liquid), immedi- Silver plating by electrolysis, the amateur Then remove the work and rub with very ately following this flickering striae appear, usually finds a difficult operation. But this fine sand to determine whether the silver unrest pervades the tube, and then the is because he does not know and observe is depositing evenly. If it is not, repeat the liquid has become a gas. the necessary precautions. In electroplat- whole process, starting with the first clean- Contributed by ERNEST LINDER. ing of all kinds the prime consideration is ing solution and ending with the electro- absolute cleanliness. lytic deposition of silver having as before Set up your plating bath as shown in the NOVEL DRYING TUBE FOR GAS a current of 2 amperes. GENERATOR. diagram, using about, 8 gravity cells or 4 Now cut out all but one cell and with a storage cells. An ammeter connected as current of about 3/10 of an ampere con- Large or medium size test tubes break shown is highly desirable. A solid silver tinue the process until the requisite thick- quite frequently, and these tubes may be anode about the size of a quarter must be ness of silver has been deposited. put to good use by making drying tubes suspended at the positive pole and the ob- Remove the object, rinse in water, bur- ject to be plated at the cathode or negative nish and buff it. Rubbing with rouge - We/ Woo' of Drying pole. red oxide of iron-is the best method of Cotton TUleiVoi,fom First polish the object to be plated after buffing. Cork &vimtes/1uLr Coá In using cyanides exercise the utmost care. Do not inhale cyanide fumes, for they are poisonous. (Bubxrtubiny Contributed by FLOYD L. DARROW. `Cork Co C./; Olive dolite THE CRITICAL STATE OF MATTER. /tow to cut áro/ten st tote Crocked bottom = When a gas is at the critical temperature of tube \ and at the critical pressure also, the in- crease of pressure or decrease of tempera- ture will convert it into a liquid. When in ,L,+dC/ford: this condition a gas is said to be in its _ YoCy +NC/ ArCq, = B- critical state. ,rrS+//C/fa-HS G,+// NO CE The phenomena of the critical state can CC be beautifully shown as follows :- Select a test tube at least 8 in. in length and 1 in. Diagram Showing How to Set Up the Silver - plating Outfit. in diameter. This should be filled with Gas Should Be as Dry as Possible. This in- paraffine. Also procure a glass tube about expensive Gas Dryer Should Be Welcome In Every Laboratory. which remove the grease that will surely adhere to it by dipping in water and then from them. This is done by cutting off for a half minute in a cleaning solution the cracked part (B). Procure two corks made as follows : to fit the ends, each having a hole thru Caustic soda 100 grams which a small straight or curved piece of Water (preferably distilled) 1000 c.c. tubing passes. (A). Insert one of the The temperature of this solution should be corks, and on top of this a small wad of about 40 degrees Centigrade, or 104 degrees cotton. Then fill the tube with calcium Fahrenheit. Remove the object, rinse in chloride, leaving enough room for another clear water and then to remove certain wad of cotton and the other cork. This oxides that still remain on the surface dip dries the gases very well. for a half minute in the following solution : The generator can be made from a small Potassium cyanide (very poisonous) olive bottle. (A). Bore two holes in its 25 grams cork, and in one insert a funnel tube, thru Water (preferably distilled) 1000 c.c. the other a delivery tube. This apparatus After removing from this solution rinse as when made costs practically nothing. Even before in clear water and ..avoid thruout the funnel can be made from glass tubing, handling with the fingers, which will again with a little care. leave grease upon the surface. If it is charged with hydrochloric acid Now to roughen the surface so the silver (or sulfuric) and zinc; hydrogen is gen- will get a firm grasp place the object for erated, and is freed from moisture on pass- a few seconds in the following solution: ing thru the drying tube. It is then good Mercury (dissolved in dilute nitric acid) for the marsh gas test, it being necessary 1 gram to have the gas dried for this test. If Water 2000 c.c. charged with calcium carbonat or marble, Then quickly rinse in about 2 quarts of and hydrochloric acid, carbon dioxid is clean water. generated. If iron sulfid and hydrochloric The plating bath itself is made as fol- acid are placed in it, hydrogen sulfid is lows : Dissolve 56 grams of silver nitrate produced, and this apparatus can be util- in a small volume of water and likewise ized for making nitrous oxid by charging 50 grams of common table salt in another ei it with scrap copper and dilute nitric acid. equal volume of water. Mix the two solu- Of course, separate ones can be made for tions and white silver chloride will precip- A Fine Experiment to Demonstrate the Criti- cal State of Matter. Caution! Use Wire each gas, which would be better, as the itate. Filter this precipitate in the ordi- Netting Over Your Gas Flame When Sealing material is not very expensive. nary way with funnel and filter paper, or Ether Tube. Very inflammable. Contributed by better still thru clean unbleached muslin. EDWARD MARENZANA. Wash the residue left on the filter by pour- 4 in. long and 5 mm. outside diameter. Seal ing water thru it. one end by holding in a flame. Fill one - Then make another solution of 225 grams half full with ether, and seal other end CEMENT TO MEND LEAKY of potassium cyanide in 1600 c.c. of water with blowpipe. The paraffine is now melted BOILERS. and in this solution dissolve the residue of by holding test tube in flame, and the small Powdered litharge, 2 parts, very fine sand silver chloride from the previous operation. tube suspended in it by means of a wire, 2 parts, slaked quick lime, 1 part. Mix all Heat the plating solution to about 45 de- as shown in illustration. On continuing to together. To use, mix the proper quantity grees Centigrade or 113 degrees Fahrenheit heat the wax the ether will go thru the with boiled linseed oil and apply quick. It and place in the plating jar. Having placed critical state. gets hard very soon. 906 ELECTRICAL EXPERIMENTER January, 1920

ERs`E 11[o 13 UCINIERO1SV p Enságrri U. S. Ho Ro F. N the bewildering maze of inventions Ft Es litt and receiving "radio -goniometers." The re- and discoveries which have been de- What What ceiving goniometer was later modified and veloped during the very short years Does How lit Does Btt- adopted by the Marconi Co., and at the following the entry of the United oft' IIt beginning of the war was considered the States into the World War, there Whc Makes Use most developed and accurate radio compass stands out an instrument which has the the navigation of ships almost fool -proof. of the day. It took a war to bring the de-

Copyright. 1919, by E. Y. Co. This View of a Typical "Radio Compass" Station as Maintained by the U. S. Navy Along Our Seacoasts is Correct In Detail and was Drawn by the Artist From Sketches of Actual Stations Furnished by the Author. These Ship Locating Stations Provide An Invaluable Service to All Mariners Approaching Large Harbors, Such as That at New York City, and the Layout of the Several Radio Checking Sta- tions Is Shown In the Map on the Opposite Page. The Loop Antenna Is Swung on Its Pivoted Vertical Shaft Until the "Weakest" or Critical Sign is Heard from the Ship and the Position of the Coil, in Geographical Degrees, is Read Off the Scale and This Information Telegraphed to the Central Checking Station in New York City. When All the Stations Have Been Heard From the Resultant Information or the Exact Location of the Ship Is Radioed Her Captain by the Navy Station. unique feature of being at once a formid- HISTORY. vice up to its present degree of perfection, able aid to naval and aerial maneuvering Before serious attempts were made at and the U. S. Navy Departm9nt, with the during war -time, and war having ended, radio direction finding, much experimenting assistance of Dr. F. A. Kolster of Kolster takes a prominent place as a new and valu- was conduced by such pioneers as Messrs. Loop" fame and other U. S. Bureau of able aid to the navigation of all maritime Hertz, Zenneck, Marconi and Pickard to Standards experts, as well as Lieut. C. W. nations. Behold, that important and valu- discover methods of directing transmitted Horn of the Third Naval District sector, able instrument is -the Radio Compass. waves in certain desired directions. That is directly responsible for its present ef- It is perhaps a strange fact that this in- is, large metal screens were employed to ficiency. The adage "Necessity is the vention comes to the aid of a science which, deflect the emitted waves in single lines of mother of invention" proves its truth in altho a very ancient one,. has changed very directions; these screens or reflectors hav- the fact that upon the United States' entry little in its broad fundamental principles. ing the effect of causing little or no radia- into the war, Navy radio found itself con- Modern navigation methods differ slightly tion in one direction -the maximum energy fronted with the immediate necessity of from those of olden times and for that being reflected to the opposite direction. supplying itself with accurate means of reason the radio compass may be con- Messrs. Bellini and Tosi did their share in locating enemy radio stations, be they high - sidered as one of the first practical inven- developing the present day radio compass power long distance shore stations -which tions of the day designed to aid and make by devising their so-called transmitting seemed to spring up like mushrooms over- January, 1920 ELECTRICAL EXPERIMENTER 907

night -or raiders, submarines, etc. The re- sult is that today the American Atlantic coast is literally dotted with groups of radio compass stations ready to aid any vessel equipt with radio, merely for the asking. The radio compass is being in- stalled on the Pacific coast as well ; and while an invaluable boon to peace -time navigation, will also prove itself indis- pensable during war -time by readily locat- ing the positions of hostile warships ap- proaching the America coasts. For, much as may be said to the contrary, there are times when war -craft are obliged to use their radio apparatus, and vigilant radio compass operators stationed along the coast will readily determine their approxi- mate positions and courses so that effective counter -maneuvers may be directed against their approach. GENERAL DESCRIPTION. The radio compass is nothing more than a highly developed receiver employing a so- called "loop" instead of the usual straight antenna and ground. The loop consists of a box -cage arrangement built of light wood six feet square, upon which m t is wound 12 turns of insulated stranded copper wire No. 12 B. & S., gage, making all told approximately 288 feet of wire. The framework of the loop is supported upright by a long brass shaft reaching from of the the top of the loop to the bottom SNIP SUNG LOCATED compass house. The two loop wires lead SENDING OUT RADIO ... to collector- rings, the brushes of which CNLCKINO SIGNALS. further lead to the receiver, thereby en-

, abling the loop to swing at all angles. The Pte.! compass dial is installed in a stationary e< and has position convenient to the operator How the Five "Radio Compass" Stations for Locating Incoming Ships Are Spread Out inth a reading scale graduated from 0 to 360 Vicinity of New York Harbor. Lines Drawn on the Chart From Each Station intersect at a degrees, corresponding to a ship's compass. Point Indicating the Position of the Ship Sending Out the Signals. fast the An adjustable pointer is made to having brass shaft supporting 'the loop and running netic materials ; copper nails being employed designed set a primary, secondary, thru the center of the dial; this pointer thruout in construction. Unlike the regu- loading coil, vacuum tube connected to act pointing to zero of the scale when the plane lar land radio stations there is no visible either as detector, amplifier or oscillator, of the loop is pointing directly at right external evidence that the queer looking as well as the usual receiving appliances. angles to north. This adjustment, of Next to the receiver proper is connected a course, is made at the time the loop is Navy -Standard type two -step amplifier with erected. 600 /17Ele7:5 a plugging device for the very sensitive In order to eliminate all possible mag- pair of high resistance telephone receivers netic influences, all parts of the loop and furnished with each installation. This two - objects are devoid of steel or step amplifier is a very necessary adjunct surrounding when it is considered that the minimum iron fittings ; non -magnetic metals, such as and aluminum being used thruout in- amount of received energy is the one brass utilized when bearing readings are made. stead. The upper and lower ends of the fig. 2 brass shaft rest upon bearings, making it The operating room containing the re- ceiver is carefully "screened." That is to possible to revolve the loop 360 degrees Illustrating the "Wave Length" of a Radio with ease. Contrary to popular belief the Wave, or Oscillation. say, it is surrounded from all sides by a loop is not exposed outside of the compass rounded copper netting. This precaution house. Instead, and as will be noted from shacks along the coast are even remotely is necessary in order that possible stray the accompanying figure, the loop is in- associated with radio work. external oscillations be warded off from closed within the house and thus protected The receiving apparatus which accom- the receiver, otherwise these undersirable from the elements. The house or cabin is panies the loop is situated in the lower currents would influence the receiving ap- non -mag- part of the room and consists of a special y paratus and render loop bearings inac- bu It entirely of wood and other curate. Fig. 6 is a schematic circuit diagram of the radio compass. It will be noted that no ground circuit is employed and that the Revo/ub/e rad/O. loop leads are connected directly to the f compass cod loading coil of the secondary inductance, RECE/VER AMPL/F/E.2 instead of the primary, as is customary in other receiving circuits. No use is made of the primary; the loop circuit being a Audion direct -coupled one. + THEORY OF OPERATION. T #1! gallery In order to properly understand how the radio compass functions, it is perhaps not Audios Tronst Audios untimely to explain a few fundamental facts concerning its theory. To begin with, one may as well be re- c.- minded that present day investigators have . , decided that the radiated oscillations from Coi/1ro/ J e any radio transmitter travel over the earth's surface in undulating waves having a broad JI a a Tronsf flat front ; in other words sine waves, I j l7 similiar to alternating currents, shown in Grt/ducled VC ì dia/ i, Fig. 2. The distance from A to B is equal '_t=;4 y hónes to the actual wavelength of that partic- Loase ular transmitter, which in this case we as- Pivot-.....i mole,- fI'I it BarII'I sume to be 600 meters. fi.g. 6 Now if the plane of the loop windings is set at right The Connections Used In U. S. Naval "Radio Compass" Stations. The Details of the angles to the advancing wave Loop Antenna Are Given in the Text. (Continued on page 949) 908 ELECTRICAL EXPERIMENTER January, 1920 oacIlilflIlon Raid IlO Te ophone and Te egiraph This may be done when it is installed and once these adjustments have been made it will need no further attention. Absolutely no knowledge of radio telephony is neces- sary to successfully operate the set, and the non -technical man can run it just as well as the most up to date radio engi- neer. It is as simple in operation as the ordinary house telephone. One of the advantages of this radio tele- phone which will be duly appreciated by those who have had experience with the older types is the remote control system, by which the antenna is automatically con- nected to either the transmitter or receiver, by merely pushing a button. The telephone is designed primarily for 200 meter transmission, but sets can be made to operate on other wavelengths when desired. One 6-volt storage battery is needed in connection with the telephone to operate the microphone and the remote control relay. Any standard storage bat- tery will be satisfactory for this work. Us- ing this radio telephone in conjunction with standard receiving equipment ranges of ten miles and over may be reliably covered with a moderate sized antenna. The New De Forest Radio Phone, So Simple That a Child Can Operate It. It Works on The panel on which the apparatus is A. C., Thanks to the Two Rectifier Tubes Seen at the Bottom of the Apparatus at the Left. Just Press a Button and Talk-More Simple Than the Regular Telephone, Eh? mounted is of Bakelite 14x20 inches. It sets on an oak base 14x15 inches so that ALTHO the A. C. Oscillion Radiophone of the instrument is quite simple. All that the complete set occupies a minimum of Transmitter is something entirely new is necessary is to connect the power leads space. At the top of the panel is mounted on the radio market, it has been so of the set to the ordinary house lighting a microphone transmitter of the usual type carefully designed and constructed that it circuit, connect antenna and ground to the on an arm, to the right and left of which is claimed to be a practical instrument terminals of the set, push a button and is located the plate circuit milliameter which may be relied upon to give excellent talk. and the filament ammeters respectively. sérvice over short ranges. The operation The set needs to be adjusted but once. (Continued on page 954) New Undamped Radio Receiver Have you enjoyed the thrill of listening discharge. The telephone battery to the piercing whistle of the numerous un- is enclosed in the cabinet and has In the Photograph Below Are Seen damped wave stations now operating here a pressure of 40 volts, which can Two Pieces of Newly Developed Radio and Apparatus Which Are Unique In abroad? Well, the pleasure is all finely adjusted by the 19 -point De- yours, especially so as the number be sign and Construction, Having for of sta- high voltage switch. Their Objects Maximum Efficiency and tions using this method of transmission Reception of Both Damped and Un- is increasing yearly, already all the Gov- To renew the batteries it is only damped wave signals. A minimum ernment land stations of importance necessary to remove several screws Table Space Is Required. The Vacuum are dis- Tube Detector and Oscillator Is of the equipped for sending and receiving, while on the panel and base, thereby Tubular Type. placing the cabinet and making re- all the battleships are . equipped for re- ceiving, their transmitters being installed newal easily accomplished. All con- as quickly as time will allow. necting posts are clearly marked The in white letters, these being en- tone of the undamped signals can be graved in the panel. The oscillat- varied from the lowest known to inaudi- ing inductance is machine bility ; it is therefore possible to select any wound with enameled wire pitch best suited for receiving. This phe- on a substantial tube fitted nomenon is indeed interesting and in strong with a positive contact contrast to the spark method whose tone switch, which allows of suf- is fixt. ficiently fine variation. The A glance at the illustration will disclose entire set is furnished in a the advantages of the vertical mounting mahogany -finished cabinet, over the cumbersome horizontal method all metal parts being nick- which occupies unnecessary space on the eled. The height of the ap- operating table, besides ' being harder to operate. paratus is 32 inches. The principle is regenerative in action, Loose couplers have from resulting in amplification. In its construc- time to time demonstrated tion a high grade of insulating material is their efficiency in being able used upon which are mounted all the metal to tune out all those stations parts carrying the oscillating currents. The not desired and allowing windings are machine wound with enameled those which the operator in- wire on substantial tubes. The compound tends to receive from to switch permits fine adjustment on the pri- come in with marked clar- mary inductance. The counter -balanced ity and intensity. Many have secondary is a unique feature which elimi- raised objections to their nates all difficulty in tuning, instantly re- use, however, stating that sponding to the slightest touch and re- they were inefficient because maining in any position. The balanc- of their coupling, but very ing weight is contained in the long brass few have been able to pro- tube which permits the secondary to be duce other apparatus to re- loose -coupled six inches, resulting in highly place them, and which selective tuning. would be so univer- The set has a wave length range up to sally accepted "the f` 18,000 meters on a moderate size antenna. best ever." So it The detector is of the panel type, using stands to reason that the tubular bulb producing a pure electron they are to remain. January, 1920 ELECTRICAL EXPERIMENTER 909

The Simple Radio Compass Loop and Receiving Set Used on Ship to Locate Its Position From Shore Stations Fitted with Automatic Radio Transmitters.

Typical Light.House Fitted with Antenna Shore Radio Station Used In Fog Signal- for Fog Signaling Experiments, Which ing Tests by Bureau of Standards. Proved Successful. a Signz_ing

THE Bureau of Standards, of Wash- able ships to locate their positions by use three isolated lighthouses, each located off ington, D. C., is carrying on experi- of a radio direction finder. The experi- shore, on Chesapeake Bay, between the Po- ments in cooperation with the Bur- ments aimed at determining the practica- tomac River mouth and Norfolk. The in- eau of Lighthouses, to establish a bility of simultaneous signals from several stallation took about a month. It was radio fog signaling system. This lighthouses, the trial of automatic trans- found necessary to work at shorter wave system, when perfected, will give a navi- mitting sets, the comparison of damped lengths than had been planned, because gator a reliable signal under any conditions the limited space forbade erection of suf- of fog and make him independent of the ficiently large antennas. A great many lighthouse light. The principal use is the practical difficulties had to be met and sending out of a radio signal automatically overcome during the installations. from a lighthouse and the reception of this Two of the three specially designed signal upon a ship by a very simple radio In January Radio transmitting sets were rotary gap spark direction finder. If a number of the im- sets. These gave more satisfactory sig- portant lighthouses on the Atlantic coast Amateur News nals than the third set, which utilized a large electron tube. Ample power was are equipt with this apparatus, the safety The Priess Loop Set -Part II. of navigation will be greatly advanced. radiated by the electron tube set, but evi- In the experiments radio transmitting ap- By Walter J. Henry dently the radio wave was not modulated in such a way as to affect the receiving ap- paratus were placed at three lighthouses in How to Build Arc Generators Chesapeake Bay, and the radio receiving paratus used as much as the spark set. apparatus and direction finder installed on By H. Winfield Secor This will be investigated further. a lighthouse tender. Three lighthouses are The Design of Multiple Stage Am- Signals from the lighthouses were re- used so as to give comparative information ceived with a direction finder on board a on different types of modern transmitting plifiers lighthouse tender. A four -stage amplifier, equipment to determine which is the best By Prof. C. L..Fortescue, M.D., E.E. developed in the laboratory, was used on suited for this work. The apparatus is the direction finder. Experiments were of a special type developed by the Bureau Static Elimination made to find the best location on the ship of Standards as a result of some of its By Greenleaf W. Pickard for the direction finder. Calibrations were researches on radio problems during the made to correct for the distorting effects war. The Construction of a Radiophone from neighboring objects on the ship act- The Navy Department already has a fog By E. S. Rogers ing as receiving antennas. signaling system under way which is, how- Comparisons were made between the ever, considerably more complicated and A Case of Nerves radió bearings of the lighthouses and the elaborate than the one upon which the pres- By Julian K. Henney bearings obtained by magnetic compass and ent experiments are being made. The Navy by visual observation. The radio method system requires the use of several receiv- Radio Telephone on Mount Hood located the ship to better than one -half ing stations on the shore and requires the Designing an Amateur Transmitting mile at fifty miles from the lighthouse, boat to have radio transmitting equipment. and proportionately better when nearer, The Bureau of Standards system re- Antenna which is eminently satisfactory to navigat- quires only a single radio station on shore By E. T. Jones ors. Difficulties connected with simultane- and the ship to have simple receiving ap- Multiple Loop Aerial Switch ous operation of lighthouse stations were paratus. The simplicity and low cost of By John G. Merne overcome by a time schedule of transmis- apparatus required on the ship is such that sion.. It was observed that radio waves it will be possible for practically every ship Junior Radio Section apparently travel much more readily along to be equipt and obtain the advantage of By W. A. Heppner the coast than inland. the radio fog signaling system. It was concluded that this method of fog signaling is thoroly practicable. Radio FOG SIGNALING EXPERIMENTS ON signals sent out during fog by lighthouses CHESAPEAKE BAY can be received by any ship having a radio A set of experiments was made by the and undamped wave transmitting sets, the compass (direction finder). This is a Bureau of Standards during September to trial of an improved direction finder, and simple and inexpensive apparatus. With November, in cooperation with the Bureau the determination of the accuracy of lo- this system, a ship can always determine of Lighthouses, to test the practicability of cation of a ship by the radio signals. its position with accuracy when near shore, ladio fog signals from lighthouses to en- Radio transmitting sets were installed at without use of the regular ship's compass. 910 ELECTRICAL EXPERIMENTER January, 1920

New 1165 no JS errlSabre Radio The English Marconi Company has evolved a new type of mast which 165 FT LATTICE STEEL MAST has found great favor both for portable and FOR MULE TRANSPORT stationary plants. It is so arranged that it may I

AERIAL HALYARD be guyed to any tempo- PULLEY rary position such as oc- MAN HALYARD PULLEY curs with a signal corps EAEETINC HEAD. company, or it may be used in conjunction with the main station 100 miles back from the fight- ing lines. This type of mast is also applicable to small commercial sta- tions. It consists mainly of a number of steel sec- WIRE STAYS,. tions with a working scaffold. The raising of PORCELAIN INSULATORS these sections takes place much along the same lines as the tubular Mar- coni masts as used in the New Brunswick station DETAILS SHOWING METHOD wherein men working in OF MAST ERECTION this cage raise them- selves a number of feet and plate a small section of the mast into position Et and raise themselves so on upward. The mast is then guyed at points A Remarkable 165 -Ft. Steel Radio Mast Developed where needed as the con- During the War by the Marconi Engineers. It Is Adapted to Portable or Stationary Plant Require- struction goes on, and ments, and Can be Erected Quickly. It was Primarily within a short time a tall Intended for Mule Transport and for Use at Army but rigid mast is Corps Headquarter's Stations During the World the fin- War Operations. ished product,-ligh tly constructed, but rigid.

wIltoL 1(1 mac AeriIla The following is a description of a very and ground. It also completes the circuit rangement in the accompanying drawing. simple automatic aerial switch which I have thru the primary winding of the trans- As soon as the key is released the fiber devised and constructed and which works former by roller on C, coming in contact wheel returns to its former position, due very well. The object of this switch is with H, which are in series with this cir- to the adjustable spring shown, and thus to provide means of simultaneously send- cuit. This contact is not made until shortly connects the receiving set to the aerial and ing and receiving with the ordinary wire- after the sending set is connected to the ground thru contacts F and D. The wiring less set. aerial and ground, as can be seen by the ar- diagram clearly shows how this instrument Referring to the works. a c companying There are a num- sketch, the rotary ber of different drum carrying the arrangements f o r embedded copper "listening in" while contacts H, D, E, transmitting on a F, and G is made of Aerial wife H Gramd radio set. These in- fiber and is pivoted 0 from seeding set rec. set clude the break -in in the center in key system, having brass casting A. A Aerial wire 6r01//Jd frttrn AE auxiliary contacts is grounded a n d flan rec se/ B sendir/g se/ on the key, which carries a pivoted short -circuit the re- arm with a roller ceiving set, detector, contact. Casting B etc., and then there also carries a simi- is the Fessenden lar arm and is con- stunt of using a re- nected to the aerial - volving commuta- leads. tor provided with a When an ordi- set of brushes, con- nary telegraphic key nected in such a way is deprest a local that first the trans- circuit of D.C. is 4 th Aft IIIIIIIIIIIIII mitting set, and then completed thru the uiiu.!ii the receiving set, are electro- magnets I. w put into circuit suc- This pulls down the cessively and in armature attached rapid sequence. The to the bar, which in experimenter w i 11 turn revolves the find these break -in fiber wheel suffici- systems worth while ently to bring cop- Illiiii1100011, studying, for they per contacts G and are the coming thing E in contact with t,wwilllidüdai in all modern radio the aerial and stations, both ama- ground. G.E. being teur and commer- the sending set aer- cial. ial and ground ter- Contributed by minals, this con- A Design for an Automatic Aerial Switch Intended to Provide Means for S.multaneously nects it to the aerial Transmitting and Receiving Radio Messages. ERNEST OKE. January, 1920 ELECTRICAL EXPERIMENTER 911 _3.71 LATEST PATENTS

Wave Motor. cessive surges thrown on the high mitted ihru a rubber tube and in artist or player and termed the (No. 1,318,469, issued to John F. tension winding. He further aims one form of the invention, the aural "pitch leader ". The rendition of Wilkinson.) to provide an efficient electro- static receiver is made in two halves, the master artist or player is tele- This invention covers a means shield between the high and low which may be separated and one phonically and also individually for utilizing the rise and fall as tension windings, also an arrange- half held to each car. transmitted to each player of á well as the lateral surging move- ment of the low and high tension stringed instrument in the orchestra. ments of tidal waters, for produc- windings such that in a ratio System of Acoustic Signaling. transformer, the voltage of the high (No. 1,320 686, issued to John Hays Electric Auto Signal. tension winding is maintained Hammond, Jr.) (No. 1,317,906, issued to J. J. Bene- straight, and the low and high ten- Relates particularly to a method dict.) sion windings are automatically bal- for transmitting signals of varying A novel device which may be anced. used night or day on the rear of automobiles to warn the driver of Combined Telephone and Phono- a vehicle in the rear as to when graph. and in what direction the .driver (No. 1,323,710, issued to John F. ahead intends to turn. As will be Malthaner.) observed, the signal is in the form A very clever invention whereby of a human hand and an electric a "dictaphone" may be used for light mounted on it, makes it read- recording ordinary telephone conver- ily visible at night, so that any sation, or else employed in the movements of the signal will be at regular manner, as may be desired. once noticed. The lamp on the sig- In other words, the inventor pro- vides a unique scheme whereby tele- phone conversations may be recorded upon the record cylinder of a com- mercial dictating machine, so arrang- ing the electrical circuits that under ing power. Considered as a unit, of ordinary dictating conditions, cer- which any number may be used of +. course, there is a primary power cable attached to and partially ---1--,--r-d e J° 9 wound upon the main shaft. At- tached to the outer end of this cable is a hollow air -tight float. As the characters, such as pitch and in- tidal or other movements of the tensity, and receiving and interpret- water occur, the float naturally ing them, so that they will produce moves in or out, or up and down, characteristic tones or visible char- and transmits the power thus gained acters. These audible or visible char- to the main power shaft thru a spe- acters form a telegraphic short- cial clutch, which causes the power hand system. A transmitter may from the float cable to be trans- be used, capable of producing vari- mitted to the machinery in a uni- able tones ranging in frequency directional or continuous form, no from 200 to 500 per second, for matter which way the cable moves, example. The intermediate fre- -inward or outward. quency changes may be made as slowly or as quickly as desired; Electric Riveting. thus a character such as shown at (No. 1,322,848, issued to E. Jannez tain parts of the apparatus used for A, may be transmitted by starting von Henke.) receiving and transmitting telephone with a frequency of 200 per sec- An improved technique and meth- messages may be used by the dicta- ond- raising it as quickly as possi- od of applying tor. The dictating machine has ot4y ble to 500 per second -and then electric riveting cutting it off. nal is not lighted when the signal is to sheet metal, particularly heavy to be slightly modified, and fitted in the normal condition. The hand plates. As the drawing indicates, with a small electro- magnet so as to or is operated by an there is by the telephone cur- Electric Ship Detector. semaphore provided an annular con- be operated '(No. 1,319,145, issued to Reginald electric -matmet or solenoid; this tact . block, order to avoid any ob- electrically connected rents. In A. Fessenden.) solenoid bang operated from the with the transformer secondary, jections of telephone companies, no car by means of a push mechanical or electrical connection Professor Fessenden's scheme battery and here shown, covers the detection button conveniently located. between the telephone proper and location of ships and other the recorder or dictaphone is neces- Sound Transmitter and Receiver. sary. (No. 1,321,197, issued to H. J. W. Telephone Receiver. Fay.) (No. 1,321,171, issued to Maximil- An improved device for the trans- ian Weil.) mission and reception of sound A scheme fer utilizing aural waves thru water. It comprises a receivers in conjunction with the device analogic to a telephone re- usual telephone and in which marine bodies, particularly when an ceiver with such structural changes approaching ship is located over a as will adapt it when used as a mine and in such a position that it transmitter to produce a maximum while a second electrode is placed will be exploded if the, mine is de- of mechanical vibrations with a mini- under the rive as shown. As the tonated. The device proper com- mum of electrical energy to cause rivet blank is inserted cold, it can prises a large diafram, which the in- said vibrations, as the telephone be given a tight fit within the holes ventor has found very sensitive to in the plates so that when the cir- distant sounds, and on the inside of euit is established, a heavy current this diafram there is mounted an will flow from the top contact block, inertia type carbon microphone, thru the plate, across the joint be- such as the Skinderviken. tween the rivet shank and the wall of the hole, thence thru the rivet Musical Composition Scheme. shank and thence to the lower con- (No. 1,323,218, issued to Thomas tact block. A. Edison.) Transformer Protector. This scheme devised by Mr. Edi- (No. 1,317,767, issued to C. H. son, relates to the rendering of Thordarson.) musical compositions by a plurality This idea aims to provide a pro- of players, such as an orchestra, and tection in transformers between the is arranged so as to provide a meth- low tension winding and the high od for enabling the various players tension winding. The inventor pro - to maintain uniform pitch and poses to connect the coils of the tempo while ointly rendering a low tension winding with the low composition. The orchestra in this receiver may convert mechanical vi- tension current source, and to a brations, such as sound waves re- ceived thru the water, into electri- IIIIIII11II111111111111111 cal energy, and such electrical cur- rent when used to actuate a tele- phone receiver, will enable one to detect vibrations of very minute intensity. When used as a pro- ÿiÿ ïi %/ J' c ' ïïï A ducer of sound waves in water, a i, re- frequency alternat- scheme the usual electro- magnet source of high ceiver is supported in a guide or ing current is employed. The fre- support on the base of the instru- quency of this current should be ment in alignment with an acoustic equal to the natural mechanical 1 receiving chamber. This acoustic period of the diafram. The value grounded conductor, in such a man- receiving chamber communicates of the condenser in the circuit is ner as to prevent destructive stres- with a special form of aural re- adjusted until the power factor of ses or surges being set up in the ceiver, which is held to the ear or case has to be supplied with an the current flowing thru the helix low tension winding, due to ex- ears. The sound waves are trans- auxiliary leader, who is a master is substantially unity. 912 ELECTRICAL EXPERIMENTER January, 1920 WITHAMATEuRS

Our Amateur Laboratory Contest is open to all readers, whether subscribers or not. The hotos are judged for best arrangement and efficiency of the apparatus. To increase the interest of this department we make it a rule not to publish photos of apparatus unaccompanied by that of the owner. Dark photos preferred to light -toned ones. We pay $5.00 each month for the best photo or photos and $2.00 to each "Honorable Mention." Address the Editor, With the Amateurs" Dept. aaAmaa4c>ur Electrical Labora4®rgy99 Contest THIS MONTH'S $5.00 PRIZE WINNER - HONORABLE MENTION, ANTHONY MAG R. N. RHODES $2.00 PRIZE PAID EACH "HONORABLE MENTION" E accompanying photos are views of my electrical "Lab." I IHAVE a large portable garage for my "Lab," and have gas and have been for a number of years a close student of electricity. electricity installed therein. In my electrical section, I have a I am sixteen years of age, a high school student, and greatly large grinding machine with three grind stones of various sizes interested in the scientific arts. I have seven different kinds of and coarseness attached to it. This machine is run by a H.P. motors-one an induction motor, volt-ammeter, test tubes, electric motor. I also own a large work bench and strong anvil vice. On bells, all kinds of copper wire, and small electrical fittings, etc. The the right of this bench can be seen my switchboard which controls electrical division contains among other things, 50 watt step down the motor lights, transformers, etc. On my bench are seen a transformer, a four magnet generator which I use to test coils number of generators, motors, a circuit breaker, two transformers, lights, etc., and have lots of fun using it for a "shocking machine." one storage battery, and various tools. Here I construct apparata Among the home -made apparata are: -an electric stove a rectifier which I often sell and trade. On the shelves I have resistances, to change A.C. to D.C. and charge small storage batteries, also an three ammeters, two voltmeters, galvanometers, wire, tinfoil, lamps, arc light, and polarity indicator. I have also a collection of a lamp bank, switches, static electricity apparatus, electroscopes, miscellaneous articles commonly known as "junk." The usual receivers, transmitters, buzzers, bells, electrolytic interrupter, Ley- collection of "miscellaneous," comprises telephone parts, coils, den jars, glass plate condensers, step -up transformer, two tele- binding posts, aluminum, and other numerous accessories. I also phones, et cetera. have tools of all kinds, hand drill, gasoline blow torch, etc. The In m chemical section, I have over two hundred and fifty static machine is of the Wimshurst type. I made this machine chemicals and a great deal of apparata, such as ring stands and out of two seven-inch grafonola records and with brass fittings that rings, a large microscope -which is invaluable to me, a large gas are found in every Amateur's work -shop. It has sixteen tinfoil and electric furnace, beam balance and weights, condensers, flasks, sectors on each plate and is insulated from the frame by rubber beakers, evaporating dishes test tubes, test papers, graduates covered knobs. pipettes, blow pipes, sand baths etc. Under my microscope I In the photo to the right can be seen my cabinet, which I made test cloth, etc., and the chemicals that I make, I test and sell. to hold small articles. It has 75 drawers, made of cigar boxes. A book case and desk add to the many conveniences of the The drawers are properly labeled. To the right of it is my home- "Lab," and it is here that I do all my writing and calculating. I made book -case, and I have 44 scientific books, as well as files of have a number of mechanical drawing instruments and I develop Popular Mechanics, the ELECTRICAL EXPERIMENTER, and `Hawkin's and print my own photos. I also have electrical, chemical and Electrical Guides." -R. N. Rhodes, Fordyce, Arkansas. wireless books.- Anthony Mag, 4212 Penn Ave., Pittsburgh, Pa.

a January, 1920 ELECTRICAL EXPERIMENTER 913

By EMERSON EASTERLENG 'HE Great White Way!" EIlecQaIlCI~ thing. This was way back in-1882. Today We had just turned LIlghe on -but you can see for yourself. into that modern ac- Lieht "For a long while before Edison came complishment of the around with his impossibility, the public great God Obdura we witness along this thorofare; finally, spraddles around in the flickering flare of Mazda, and Bender had they satisfied themselves that the thing had the old arc lights. We had the great minds let loose with a young `got on' and that they had gotten away with like Gramme, Thomson, Houston, both y e l their stunt and so they hit the pad for the singly and combined, to be thankful to for "And we owe it all big snooze that they had neglected. When the flickerers. Gramme is guilty for the to Tommie Edison," put in Punk. they rubbed their orbs after the series of reason for the arc lights on the corners "If you want to have it that way," inter- selections at nasal delivery, they saw that and such guys as Brush and the others for posed a voice -and a body also interjected the light still burned. It was the light that the lights themselves. itself in between the mem- "Edison had the right bers Punk and Bender. idea when he took out his "What the 1" I ex- patent. If you should in- claimed, seeing Jazz vestigate you will find that Stokes, "I thought you it covers the whole system were at the power plant of generation, distribution seeing the watts wattle and what else he could along the wires." stretch it to mean. He got "I was," he returned. a blanket patent, all whole- "But I had to see the silk sale, no retail either. He legs for a change -so I did not patent the light dropt down to the little alone, to reap the millions metrop." off it. He patented the sys- "We have nothing to do tem, to reap billions from. now but walk down to the "A young American over theatre -we've gone on a in England, in 1845, got out strike with the cab drivers, a joke patent on the light I mean we walk -so let question. We might have loose with some of your heard from the chap in bull and enlighten us about other lines but he kicked the the in(can)descent light old oaken tub at the age of stuff. I'm dark on the sub- twenty -five-so "In the old days- before ject," Punk rambled along. "Yes," put in Bender. the transformer trans- "Get back to the very be- formed the D.C. to A.C. we ginning. ' This bird Thade -" here is writing your palaver "Say," I interrupted, "but up for the ELECTRICAL EX- you put us wise to that a PERIMENTER, and the darn couple of issues ago and I fool seems to be getting have to have new junk or away with it." the space will be taken up "Well," began Stokes, "to with `How to convert junk be real historic, our friend into wireless apparatus' or Sir Humphry Davy way 'What I did with MY old back in 1810 in the Jack Ox buzzer' -get the idea ?" country pulled the first "Pardon me, Emerson, boner in the 'lectric light but we will then indulge in stuff when he heated a plat- the subject of lights, elec- inum wire until it glowed tric, and those caused by out the primeval electro- electricity : firstly, we have spectro- radiation. It was two kinds-what? No, not good and no good. We primary stuff ; any kid does it now -but, get the point, have the arc and the incan- it was the first stuff in that descent -that is mainly -a line. vapor light is in reality an "When we discuss the arc of great length-per- practical electric light we haps you think differently. stick up Tommy Edison as "In the arc class we have the old man. He had a lot the Carbon arc, the flaming of guys in his laboratory arc (carbon) and the same carbonizing everything in both the open and en- around the place that could closed type and the mag- be made into a filament - netic and mercury arcs and why, he had a bunch of the quartz eradicators of hoosiers galloping into the darkness ; also they come in the glass variety, all sizes wilds of India and South We Discuss the Practical Electrical Light, We Stick Up Tommy Edison "When and half a dozen colors ; six America in quest of the as the OLD MAN. Why He Had a Bunch of Hoosiers Galloping Into the Wilds elusive bamboo specie -he of India and South America In Quest of the Elusive Bamboo -for he Figured shades of the colors around figured that bamboo was that Bamboo Was THE Stuff for His Lamp Filament. It Was! Tom then the high speed end of the the stuff for the filament in Guessed that If the Gas Companies Could Pipe Gas Around and Peddle It to spectrum. To be explicit: his new impossibility. He Unsuspecting Consumers -Why Couldn't He Do the Same With Electric three tones of violet and would get a light about as- Juice? He Did, You Betcha!" three of the same with spasms of green and yellow. sembled and whoof ! she - have it. "Cooper Hewitt is the guy who gets most would go fluey ! -he mopped his dome, gave never failed. And we still a verbal recitation in slang, and began at "From that day on Tom has had his fin- of the credit for the vapor type as he the first act with the tragedy again. If at ger in the light game. It started when he gassed the world in the movie realm when first you don't succeed, etc. He didn't figured that if the gas companies could pipe he sneaked in and set up his brand of the write that. He executed it. After some gas around and peddle it to unsuspecting artificial daylight and made it possible for forty 'leven fizzles he had the luck to get consumers-why couldn't he do the same the directors to get in on the night shift the juice squirting through his model of with the juice? at the studio. what the candle gave way to. "He could and did, you betcha! "When we get onto the incandescent type "For forty -eight hours he, and some of "Working with this in mind he con- we have to dwell on the first dim carbon his attendants, sat gazing at the red -white structed the Pearl Street central station lamp made from grandma's old shoe lace glow on the wires and he seeing in it what with the big clumsy generators and every- (Continued on page 933) 914 ELECTRICAL EXPERIMENTER January, 1920 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 publisht. Rules under which questions will be answered: 1. Only three questions can be submitted to be answered. 2. Only one side of sheet to be written on; matter must be typewritten or else written in ink, no penciled matter considered. 3. Sketches, diagrams, etc., must be on separate sheets. Questions addrest to this department cannot be answered by mail free of charge. 4. If a quick answer is desired by mail, a nominal charge of 25 research work or intricate calculations a special cents is made for each question. If the questions entail considerable are answered. rate will be charged. Correspondents will be informed as to the fee before such questions

ONE FILAMENT BATTERY FOR Poorly bonded trolley or electrical rail- at first thought, but it is well to remember TWO AUDIONS. way tracks also cause this trouble in many that the ground is not a very good con- instances. The heavy return current which ductor, especially in small areas. If you 1033) Joseph R. Matteson, Philadel- normally is supposed to pass thru the rails have ever stood on the ground with ordi- phia, Pa., asks : to the power house being unable to nego- nary nailed -sole shoes, and touched an elec- Q. 1. Give diagram for using a common tiate the high resistance fish plate, joints at tric light socket or live wire of 110 to 220 filament battery and two audions. the junction of the rail sections, hence leak- volts potential, You have undoubtedly found A. I. Herewith is a hookup showing ing away thru the ground and causing very that you_will get a very strong current thru how to use a 9,000 ohm auto or a two -coil serious disturbances in many cases. the body, and if the ground happens to be transformer, with an iron core, so that In this same direction another peculiar damp, the stronger the current received. one storage battery will light the filaments incident may be mentioned where a trolley Also if the shoes are damp, you will get a of two audion bulbs. The diagram clearly 1,,,,,,,,,,,,,,1,,,u,,,i ,,,,,, ,,, ,,,,,,, , ,,,,,.,,,,, stronger current than if they were dry. On explains connections. a perfectly insulated electrical distribution WANTED!!! system, you should not receive a shock by "ODD PHOTOS AT $1.00 EACH touching one side or the other of the live circuit, and while in contact Here's what we want i What have you got? with the ground thru your shoes, but if the system is ELECTRICAL PHOTOS- grounded on one side (or it may be ground- New photos of Lightning; new and ed as in the three -wire system for lightning unusual Electrical Apparatus and protection), then, of course, when touching Machinery; Electric Signs; Electric one of the live wires of the proper polarity, Autos; Electric Clocks. you will form a complete circuit thru your SCIENTIFIC PHOTOS- body down to earth and thru the soil, back New Scientific Apparatus; Results; to the grounded conductor connecting to Effects; Motion Pictures; Stunts. the other side of the circuit. OPTICAL PHOTOS - The problem of electrolysis is a large Peculiar stunts obtained with vari- one and is engaging the attention of all city ous lens arrangements; odd film ef- engineers, for these stray currents play fects caused by unusual conditions; great havoc with the buried metal pipes and novel micro -photographic subjects. conduits forming the water and sewerage ASTRONOMICAL PHOTOS - system of cities. A stray current will often New eclipse photos; star and moon pass from a poorly bonded railway track to effects caught by the camera; a metal pipe line ; where this current leaves comets; shooting stars; progressive the pipe, it carries some of the metal along moon studies; moon and star with it, thus slowly decomposing the pipe. Circuit Employing Common Battery for Two photos. Some of these pipes are so riddled with Audions. A Common Battery for the Plate FREAK PHOTOS holes as to be veritable sieves, when they Circuits of Two or More Audions Is Quite - are finally located and unearthed. The trol- Common. Odd double and triple exposure ef- fects; novel and striking effects due ley companies have to keep constant watch to unusual exposures. on the copper cable or wire bonds joining ELECTRIC SPARKS FROM WATER MECHANICAL PHOTOS - the ends of their trolley rails, for these AND GAS PIPES. Electrical and Mechanical apparatus reasons. (1034) H. L. Allen, Jr., Arctic Center, of unusual news interest. DYNAMO VOLTAGE QUERY. R. I., writes "The Oracle": RADIO PHOTOS Q. 1. - Stating a peculiar case where elec- New stations, both commercial, gov- (1035) A. L. Haynes; Clifton, Kansas, tric sparks were obtained from .a gas pipe ernment, writes the Oracle :- and heating and private. Owners of a furnace, in the same house. private or amateur stations will find Q. 1. With reference to a transformer A. 1. With reference to the peculiar elec- a special for boosting the voltage of a D.C. dynamo trical problem you describe, contest for these photos as near as we on another page of this issue. while it is accelerating. can judge from the meager details given, A. 1. Concerning data for a small step - the spark obtained between the gas burner And don't send us plate or film "nega- up transformer to be used on a direct -cur- and the base of the heater in the house in tives"; send unmounted or mounted rent generator, would say that this is im- which there was no electrical installation "prints ", preferably a light and dark possible, as a transformer must be operated of any kind, undoubtedly can be accounted one. Enclose stamps if photos are on alternating current in any case. for by electrical leakage currents or straight to be returned and place a piece of The best thing you could do in this ground currents. The electrical railway cardboard in the envelope with direction, probably, would be to arrange and trolley systems are particular offenders them to prevent mutilation. the field winding on your machine so that in this direction, and there was a case simi- Address photos to- Editor "Odd the field coils could be connected in paral- lar to this one on the outskirts of an East- Photos ", Electrical Experimenter, 233 lel, while the machine is accelerating, and ern city some years ago, where sparks . such Fulton Street, New York City. in series after the machine had attained as you describe occurred, and where there normal speed. This will have the effect of was no electrical installation or wiring for illiiii,m,,,,i11,,,1111111111,11111131,,,,o1111011111111111111110,,,,111m11111111111ll causing the field coils during the accelera- over a quarter of a mile. It was possible feed cable or auxiliary feed wire broke tion period to take more current, thus pro- to light a 110 -volt lamp by connecting the down, causing a heavy current to pass thru ducing a stronger field, which in turn would lead wires to the water -pipes. the ground to the trolley rail or return cir- produce a higher voltage in the armature. This peculiar phenomenon was finally ac- cuit, and a team of horses approaching the Later, when the machine had attained nor- counted for by the fact that one of the trolley crossing at this point were instantly mal speed, a specially arranged quick -throw trolley feed cables had broken down, thus killed by the difference of potential created switch could be utilized to throw the field causing a large part of the current thru when they rested their front feet on the coils in series, causing them to take less the main line to pass thru the ground, ad- trolley rail, while their hind feet rested on current and to produce a normal field jacent to the trolley system. the earth. This may seem a little peculiar strength. January, 1920 ELECTRICAL EXPERIMENTER 915 Why Ele cinca! Workers Are Needed. Consider for a moment what part electricity plays in ti- every -day life, in the comfort convenience, pleasure and even health of the whole civilized world. Think of having to ride in horse of waiting days for what the telegraph cars again- does in a Few minutes - of writing a letter every time of no automobiles or moving picture you now phone- shows - Electricity takes millions to and from work. Without it the automobile and airplane would be impossible -the telephone and telegraph would be useless. All the civilized world relies on it for light, heat, transpor- tation and communication. In a thousand ways electricity is used in factories, offices and in the homes. Electricity is almost as essential as the air we breathe. Busi- ness would be almost at a standstill if deprived of its energy. To say that electricity is still in its infancy is no exaggeration. Every What Electricity day brings into practical use some new method of controlling it, some new de- Offers You vice or appliance for using it. In in- Now You Can are still scores of Once you have mastered dustrial work there the A-B -C of electricity you Qualify operations where electricity will be are confronted with un- utilized sooner or later. The day is limited opportunities for You don't have to interfere coming when the railroads will entirely advancement. You can with your present work while qual- replace steam with electricity. Doctors, specialize in extending and perfecting the ifying for a good electrical position. dentists and scientists are only begin- wonders already accomplished in the field. The American School can give you ning to realize the possibilities of elec- may up branches of just the training you need in your You take those electrical SPARE TIME. trical energy. and mechanical work which cover the de -' Our electrical sign and manufacture of electrical apparatus courses have been specially pre - These facts merely touch the pared for home study -are written high spots, yet they prove beyond a or start in to qualify for a well -paid position in the designing, construction, operating or so you can understand everything doubt that electricity plays a vital part quickly -and from your first lesson our individual lives, and consulting branches of the electrical engi- in business, in profession, and to fit yourself until you get your Diploma expert that there is unlimited scope for those neering eventu- instructors coach you. Our train- their life work. ally for a position as Distribution, Operating, who make electricity Testing, Erecting or Designing Engineer. ing will enable you to get into the The electrical worker provides game RIGHT. other men light to work by, the tele- In the automobile, airplane, tele- phone and telegraph to convey their phone and telegraph lines there is also great Read This orders, the power to run their machincn scope for the trained electrician. Many won- and transport their goods. He sup- ders of electricity have yet to be unfolded- Guarantee plies power in the homes to operate its uses multiplied - and opportunities still washing machines, vacuum cleaners; greater for those who can qualify. for ironing, heating and ventilating. In -Then Act short, it is the electrical worker who makes With all these indisputable "We guarantee at any time it possible for the world to live more com- facts-things you absolutely know during the first year of your enroll- fortably, to enjoy more pleasures and to to be true -can you doubt for a do a bigger, more profitable business. ment to refund the entire amount moment that in choosing elec- paid if, immediately upon the com- Try to realize just what it tricity for your lifework pletion of ten examinations, you would mean if the world were you are making a wise notify the School that you are not deprived of this wonderf ul energy choice, satisfied with your course." , and you will have a better idea of its importance and under- stand why the electrical worker is always AMERICAN SCHOOL needed. OF CORRESPONDENCE Dept. G 261 CHICAGO

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You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 916 ELECTRICAL EXPERIMENTER January, 1920 Po ó uL.tn- A5tTORICIULY By IIembeR LevynIl5p Ma A. (Continued from page 887) Let the mirror be fixt at equal distances of the Kaufman -Bucherer experiments on Auto and Tractor Mechanic from A and B in the two systems. A and the mass of electrons shot off from radio - Earn $100 to $400 a Month substances or in cathode rays. Young man, are yo B will agree that AM equals BM' for the actiive mechanically inclined? two lengths can be directly compared by A still more startling conclusion arrived Come to the Sweeney School. Learn to be assuming A to come into coincidence with at is that mass itself is a manifestation of an expert. I teach B and M with M' as the systems pass. a certain form of energy and that "the in- with tools not books. Do the work yourself. That is, two observers on relatively mov- crease of the kinetic energy of a particle, that's the secret of the ing systems will agree in their estimate of in ergs, is equal to the increase in mass, SWEE!!EY SYSTEM the length of a line that lies perpendicular in grams, multiplied by the square of the of practical training by which 6,000 to their line of motion. velocity of light," and as a direct result, soldiers were trained for U. S. Gov. ernment and over 20 OCO expert Nbw let A thinking himself at rest note assuming that matter and energy are dif- mechanics. Learn in a few weeks; no previous thing, one experience necessary. how long it takes for a ray of light to ferent names for the same gram Write today for Illustrate ee cata.og pass from A to M and back in his system. of matter represents 10" (ten to the FREE showing hundreds of pictures reca Say he concludes that it takes one second twenty-first power) ergs of energy. We working in new Million Dollar Trade School. to travel to M and back over the path must come to the conclusion also that the LEARN A TRADE AMA. Let B thinking himself at rest per- two laws of the conservation of mass and form the same experiment in his system. of the conservation of energy are one and He also will find that it takes one second the same thing. SCHOOL OF AUTO -TRACTOR -AVIATION by h ss clock for light to travel to M' and 66 SWEENEY BLDG. KANSAS cI TY, mo. back (since the two observers agree on the velocity of light and the equality of AM and BM'). B assumes that the path of the ray of light in his system is BM'B AN EASY WAY TO (= to AMA) thinking he is at rest, but Don't be A who has been watching B's experiment content to from S thinks that the path of the ray of MAKE MONEY plod along on a small salary. Be independent. Go In the tire re light in B's system is BPB' where BB' pairing business. One man says "1 made $60.00 the first represents the motion of B relative to A day." Others average $200 to $600 a month. Very little capital needed. Jobs plentiful. Every motorist a pots. during the interval in which the ray of Bible customer. No experience needed. We teach you. light is passing to B's mirror and back. Repair Outfit A is surprised that B should report that the Hp,latiTire experiment takes one second, the same Improved Wrapped Tread Method time that A found for his experiment, since Used by rue Manufacturers A the two paths AMA and BPB' ap- (AM)2 = (BM')2 = (PL)2 = (BP)2 - (BL)2 Does as good work as the big high to priced vulcanizing outfits. A boy pear unequal in length so A is forced to (AM)2 (BL)? can use it. It's the only vulcanizer = 1 - Now BL is to BP as that has Automatic Beat Control. and conclude that B's time intervals are longer - - -; undercure can't or overcure a tire. than his own ; that is, that B's clock is V to c, WhereBy Is the Velocity of B Rela- Requires no watching or regulating. slower than his clock and B comes to the tive to A, and c Is the Velocity of Light. FREE Book same conclusion in regard to A's time in- 1 "Bow to Open aTire Repair Shop." tervals. That is, the two observers are in AM J v2 It tells how to make big money. Therefore . 11 Don't delay. Write quick. hopeless disagreement as to the actual BP = - c2 length of the second. From a reference C. A. SALER CO. AMA Is to BPB', as 220p Fourth St. Weapon, Wisconsin to Fig. 2 we find that the ratio of B's time and 2 AM Is to 2 BP, or interval to A's time interval as it appears v2 A B Both 1 - is to 1. But and V' -C2 SLIGHTLY USED to A is 1 : 1 - - where C is the Agree that Light Takes One Second to Travel STANDARD MAKE TIRES C' the Two Paths Unequal in Length, Therefore V the velocity of B B's Second Must Appear to A to Be Longer Size Now Tube Price Size New Tube Price velocity of light and Than A's Second in the Ratio 30x3 ..$1.85..$ 4.60 35'41..$3.00..$10.25 relative to A. That is the amount by 30x334.. 2.00.. 6.00 36a41/2.. 3.50.. 10.50 1 31x334. .. 5.50 35x5 .. 3.75.. 11.00 which B's clock is slower than A's depends 32x334.. 2.25.. 6.00 36x3 .. 11.50 on the relative velocity of A and B. v2 31x4 .. 2.75.. 6.60 57a5 .. 4.00.. 12.00 8411 - 32x4 .. 2.40.. 7.50 By similar processes of reasoning we C2 34x4 .. 2.70.. 8.50 Special -Brand New 3414%.. 2.85.. 10.00 32x334, Cord..$12.25 can deduce equally startling conclusions as a given line in B's system If the motion of the stars thru space Order now. Shipment made the same day. to the length of uni- lying parallel to the direction of motion is slightly accelerated instead of being $1 deposit required with each tire order, form, and if increase of mass and energy balance C. 0. D., subject to your examination. and find that we must come to the con- energy Specify whether you desire to have clincher or a moving yard stick (or other due to this fact can be changed into straight side tire. clusion that is source of supply unit of length) is shortened parallel to its of radiation, there then a Special cash discount of 5 per cent if full amount of the radiant energy of the sun and stars accompanies order. V that can be drawn upon for infinite ages. line of motion in the ratio of 1 - - : 1 It is also possible to deduce from the CENTRAL TIRE & VULCANIZING CO., C' 2309 S. STATE ST., Dept. E. E. CHICAGO V' as compared with the same rod at rest. form of the factor I that figures That is, the shape of a body relative to a ,\1 -9- in propor- C" STARTS ANY COLD stationary observer is changed so prominently in the theory of relativity, tion to its velocity relative to the observer, MOTOR IN A JIFFY the fact that no material body can possess all lines in the body parallel to its direc- a velocity equal to or greater than the This Electric Intake tion of motion being contracted in the ratio Heater attaches to in- velocity of light, for if V = C the expres- take manifold or car- j V' sion for the mass of a body moving rela- no drilling, buretor - I1 : 1. There is, therefore, no tive to an observer with the velocity of lapping or alterations. - - its length in the Operates from dash v C' light because infinite and switch Quick starting absolutely rigid body and the shape of a line of motion vanishes. Is, then, a ray of made sure in coldest body depends on its velocity relative to light an infinitesimal portion of an infinite weather. For any car and is different for different with storage $3.50 the observer mass or energy? battery systems of reference. A body that ap- Granted that there can be no velocity Write for descriptive pears to us to be circular, say when at rest, equal to or greater than the velocity of matter will appear spheroidal in shape when mov- light, at what speed, then, does gravitation Dealers and Agents ing rapidly and its shorter axis will lie itself act, which has always been assumed get our proposition parallel to its direction of motion. to be instantaneous in its effect? Another startling conclusion to which we It can be seen from what we have been Electric Intake Heater Co. are forced by similar processes of reason- able to state, in a more or less detached 120Corlland SLJacksoa,Mic6 ing is that the mass of a body at rest is and incomplete manner, concerning somre of less than its mass when in motion in the the chief deductions to be made frorti the us V' principle of relativity, that it deprives of our most cherished ideas concerning the ratio 1 : 1 depending on its Perfect,new tires, all sizes, non -skid or plain, -s absolute nature of time and space alld .rre- fabric or cord. Prepaid on approval. 8000 to V C relative to the observer. moves the possibility of the simultaneòius 10,000 Mlles Guaranteed velocity of events at different placees. 30,000 Customers. Catalog Free. Agents Wanted. This conclusion of relativity has re- happenings Service Auto Equipment Corporation (Continued on page 918) 1 995 Service aids., Kansas City, Mo, ceived striking confirmation in the results to advertisers. You benefit by mentioning the "Electrical Experimenter" when writing January, 1920 ELECTRICAL EXPERIMENTER 917

rg :,.. &?` ptls u.+ 3,:>'+'j+,. . l rtlitrt;P':.fl,. 4a.i.b<.,z¿'! Be a Draftsman RaiseYour Incorna Get into this paying profession and have positions opened to you by manufacturers, architects, railroads, contractors -by every kind of a corporation where mechanical design and con- struction are carried out. Draftsmanship puts you in the class of specialists, raises you above the crowd of job hunters, makes you a man whose services are needed. You have the same opportunity to get the training that other men had who took the Chicago "Tech" Course in Draftsmanship Drawing Outfit important, re- (No Extra Charge) and are now drawing large salaries and holding You also can learn how to earn Every student of the Chicago sponsible positions. "Tech" Home Study Course in Draftsmanship receives this draw- ing outfit -set of instruments in case, drawing board, T square, tri -. a Week paper, $25 to $100 angles, scale, curve, drawing pencils, etc. or a cash credit in case he already has an outfit. These instruments Not enough really skilled draftsmen are available to fill the places open are of the same to answer the call that will make and sizes as now. All you need is training to be prepared used by high sal- more money for you. Begin your training without delay. Don't waste aried experts in mean drafting rooms of time waiting. The Chicago "Tech" experts are ready today to give you the factories, shop s, enable you to step into the drafting railroads, etc. You thorough, practical instruction which will use them while some big organization prepared to do the kind of work that earns learning then room of take them- right high salaries and leads to advancement. At least write. Mail the coupon into your practical specially interests you. work. below or a letter stating which branch

Come to Chicago"Tech" Get Practical Training OR from Practical Men NO TIME PUT IN ON NEEDLESS STUDIES LESSON TRAIN AT HOME Enrollment with Chicago "Tech" means getting direct FREE personal instruction from men who for years have planned Other institutions ask you to Chicago "Tech" has its stu- and directed big architectural and engineering work in lead- ing cities. They have weeded out useless theories and need - pay first -and then to find out dents everywhere. If you lees studies and will give you the kind of instruction which men. how well qualified you are can't come to Chicago, take the will enable you to work beside the most experienced later That is one reason why you can get a complete, thorough for this profession. We send Home Study course. The same technical training here in such a short time. Also the reason are in such great demand. They lesson first and place professors who direct the resi- why Chicago "Tech" men the free go into work prepared give ervice obligation at dent courses will teach you by is the raíining you re offered eithers at the college you under no or by mail. And this is the time to enroll when there is all. Discover your qualifica- mail. You will have their per- such a pressing need for highly trained draftsmen. Use more tions pay any- sonal direction, you will learn your spare hours to fit yourself for a bigger salary-a before you important position. Chicago "Tech" offers you the oppor- thing. And see for yourself the most modern methods tunity. WRITE. - just what Chicago "Tech" all this while holding your present job. We train hun- EASY PAYMENTS offers you in training dreds of ambitious men -and Low tuition fees and easy terms of payment. Pay as you which will bring a ready go along. Get training which will soon repay in extra earn- market for your services see them quickly rise to suc- ings all the cost of the course. You know the salaries re- cess. You therefore need not ceived by skilled technical men today. Get information on and open opportunities the opportunities which are opened wide to you by Chicago to the be denied this technical educa- "Tech". We will give you all this information about fees, which are closed terms, etc., and send testimonials from Chicago "Tech" untrained man. The tion. Sign and mail the cou- graduates on how they have profited from our instruction, pon. if you will send the coupon. coupon will bring all the facts about the course, the s m a 11 fee, and the easy Auto and Gas terms. Engine Course WRITE r----- All about automobile mechanism -its construc- CHICAGO TECHNICAL COLLEGE by mail. list our principal courses tion, operation and REPAIR -taught Below we 145 Chicago "Tech" Building, Chicago 'You train directly under the Chicago 'Tech" and several others. Just automobile experts. Learn all about Principles in Drafting of the Automobile, all about Gas Engines, Power mark X in the [ ] to show which Without obligation upon me, send your Catalog on subject indicated Plants. Transmissions Lubrication, Cooling, Batteries, Starting and Lighting Systems, etc. course interests you and we will send below. Also FREE Lesson IT Inquiry Is on Drafting or Plan Reading. and information about that KNOW HOW TO FIX TROUBLES catalog X opposite work in which you are especially interested. Most complete instruction in auto repair work. particular subject. If in doubt about Mark Equips you for high pay or to start a business. yourself, tell us your ambitions and [ ] Plan -Reading-Buildings Big demand for trained repair men. [ ] Architectural Drafting we will advise you. Sending this [ ] Machine Drafting [ ] Plan -Reading -Shop Men coupon may mark a turning point in [ ] Electrical Drafting [ 1 Estimating Aeronautics your career. May lead to a larger [ ] Structural Drafting [ ] Surveying [ Metal Drafting [ ] Autos and Gas Engines instruction in Aeronautic measure of success than you have ] Sheet Complete. practical [ 1 Aeronautics Engineering. Every principle made clear. Con- expected. We can train you as we [ ] Builders' Course struction of every type of machine fully ex- plained. This course equips you for expert work. have trained others. Send the coupon Get' the catalog and information. Send coupon. today. Name CHICAGO TECHNICAL COLLEGE Address 145 Chicago "Tech" Building, Chicago City State College or Home Study? State which

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 918 ELECTRICAL EXPERIMENTER January, 1920

Double Action ie The Baby,'y Hammerless Revolver A Handsome and Most Effective Weapon. revenue. but 41/4 Inch. L41r TRNea ReE[[br .22 Calibre Cartridge* Populap Oo ..100 The new Agba M Aztc a iw,hh ,nrnariwa Re- my aber ha. d4, t Ne e i6e./ T eo for s v. Ivorthat wotbe , a Ie.enidnI fe°0°il[un.M(MWehw[vadfl, fWin,, It a small In else, ,et la (Continued from page 916) age ell roan sivee roble es the wrookil

bow to:. It. s á °ú1e:. i no w or better e mede Nan The that Ands teeter.asreureb ccideotonboo effect of the principle of relativity or of the stars toward the red due to the Not d. redore ideoal dis. -' yap LLlav it aulteture for ro upon the ordinary affairs of life is negli- fact that, according to the theory, "d é. The nbetnttt al.r. m Itl a° i the rays eO'db1.[ gible so long as we are dealing of ° nvnitto, the.féédae ned1 oo.Iibre.artidte abt..oeblo .oywwhe e: Tb. with small light emanating from the stars should r.tl of Ne soughs m.ohni.m a nIb.,.el'raoia uM.beolotely r,X.ble IÌtened thon eon be fired de. Tne revolver levey well velocities relative to the velocity of light. be constructed with Me.[ nickel rated fluted .tanbarrel of cylinder awayne only affected by the gravitational fields sur-. ouome. The d It.Beby R oINr is ells be lrla. tan ant mil, 5.X. te Ry aaar.N. It does not appear to you or to me that rounding them. So far this effect has not MIDGET BIBLE we are changing the rate of a watch mere- been found in The Smallest Bible In the World the solar spectrum tho it ly by picking it up from the table and appears to have been noted etetpaa.a carrying it on an automobile in certain TFÁat M' nTbla Iittie em4 4 :°.aárr.aw trip or that Orion type stars. a uld to brims good tuck ta tbe owner. Mu.t be r bted.AU,w1 ee.wb,ahne a moving foot -rule is any shorter than one ñübe..: b. sö q« as w. rea ejw« rnr e1.ao1 The Newtonian - fODeor{y.eU. oomone,wUi^aeiblee. lying on the table or laws of mechanics with JOHNSON SMITH & CO., Mfl. E12. 1221 Balh NaIeW that the shape and Kerl, CHICAGO size of a baseball changes as it which we are familiar are first approxima- THE U S.BABYTANK speeds thru tions MADE OF METAL. IN CAMOUrLAOEDÇ OLOEOR GRAY: the air, and for all practical purposes the to the Einstein laws and give prac- , aee°ewhe T.bk tically the same r s changes produced by motion in the in- results when the velocity nwvwÌ°lIe ootrb tonbIe stances cited are entirely in question is Ìb.Ì o negligible simply small compared to the ÌI abt.aq m b`uÌlti for the reason that the velocities to which velocity of light. It is for this reason TakÑProveddaro : we are accustomed are in general immeas- that the ié óÿ whiif ma- Newtonian law s of motion have Etyaaaé :werR,q¡$ urably small compared to the velocity of remained unquestioned for so long and Wye t Na man will keep light which is 186,000 Áaae along ^ miles per second. still remain sufficient for the solution nraru trtanw u ^e°átmNAa°^K q of m ema e .ta k[h...v a .rl Rb°ro.u.eaah. .ëmót.nbr Even the v¢ 1IÉ n u ,tewt n earth's orbital motion ordinary nIw:. H Ì r 6e . cnÉ of eigh- problems in mechanics not involv- pqaRea in oioreá pte w y merle erny iá tkrn foe- Owe DX. by áa he NAO dase ea.asab to nrdreY(.me . world. Nk.ey RUM bi, teen and a half miles per second produces ing high velocities relative 10NNSON EMITHi CO., Mot, Eli. 1224 1111 Halsted Street, CHICAGO to the velocity a contraction of only about two inches in of light. It is the satisfactory explanation the diameter lying parallel to its direction which the Einstein theory affords of cer- Make Your Watches, Clocks, Etc., of motion around the sun, so is tain Night small even facts in the realm of astronomy and edeérlñrb.liít"i this velocity compared to the velocity of electrodynamics that the Newtonian theory leWederkíTÑ DÌ1RN[°dTÑ[ IIÓNT T {MÖR[eÌ1LdLÌ NTIITeNIÑHye QÌtbi light. has failed one ou do Ile Lhe dl `I of ,evr to explain, such as the large dis- amol. 1 IA IINe .n b wmhlolastealófya ebéltrt °Ivipbtebv :tcÁ[. boa.rndalnnumerubl°bi When we come to the consideration of crepancy existing between fact and New- émeÌl titii.7 jri. zl. u'larr.r :w.°ëteá sod sï pwtEYpoié OV° aO°°rv, q° the electrons shot off from radioactive sub- tonian theory in the case of the motion of Mystic Skeleton Serpent's Eggs stances, however, we find velocities the perihelion of ; corn- Mercury, I Whe^.(_ .°teastwream^I I^ 10c D d, a aetñ..lamh.eaaanh that has given Ñoh« tehmt,oMlC hambáa irùu.IU-l°.°al(Illm parable to the velocity of light and oppor- this theory of relativity such great weight. a.áós:"d tunities are y @sÎi' here afforded to test the Ein- It is not an exaggeration m pwnam to say that this b. .om, dat.'uwy b md twlea boot Ina moat life- stein theory of relativity, and, in fact, ex- new physical theory is the most valuable ONNEON SMITH CO., ee91. EIS $224 Berp 'twee/ periments performed in the fields of elec- contribution that has been made to science All the Latest Surprising and Joke Novelties Mesmerized Penes (dallies the law trodynamics have been in accord with the since Newton promulgated his immortal RPÌnÌ.tara w°ts Pií°°nl bO° . : IOaOc of n.vteueq cleopua'. sn.Ge ben Ikellk: lee and VíN:b- Einstein predictions. laws of motion which first Palm Mesta Ifoq rom frleoL) _Cc"'ae Colog Trick are but approxi- AummoblN Poaale (t"aa0. 505 Niraer lake me pa,/ . ]Oc N,ebrlop Ghoet, ehlaq t^lsht IOo yNeck A prediction of the Einstein theory that mations to the Einstein laws developed ßubba r Mawr evan formla.bls) . Po. 1 °mltliOn'taw tTeet : : átò. ióó amherIaera.ereh I,V a fir b.gQ4eOR'i1vNoa remains to be fulfilled is that of the shift- from the Principle lwiáutitlakLy1 sMOte i,r T ere. of the Relativity 'gee- TrÌ<' u.h to tm of ar 4GaEtl á Rwpdf la 14aa 1°t I with water) . ing of the lines in the spectrum of the sun Motion. Tbm.m^a Nyate°rramTem k Gd.l le° tlwwesvdwa°n ÌÓ eb c::r swtr"li°ie el . iei.ó.en. 1oeaa iVeOe Aeawmtl.nw ;wilti :Ad M adñmTae4iotaadjok:> . " loa' wy,l,Innrr9ala:d'a.Irirlek >Zé IONNEON SMITH a CO.. DOH. EIt, Bt2f Me salmi vow, CNICp00 EXPLAINING THE EINSTEIN THEORY OF TIME AND SPACE (CoDyrlgh4 1919. by Jobn T. D1CCUtaheoo.)

'THERE ARE No STRAIGNT'LINES IN SPACE. ' TIME IS THE POuTiTH DIMENSION. ELECTRICAL FIRES LIGHT 15 WARPED BY tTS.WEIEHT AND TIME IS DIFFERENT IN DIFFERENT BY THE SUN'S ATTRACTION PLACES HE 14Ní , BREADTH, AND !. Ile0 TONS' OF LIGHT THE FALL ON DEPTH IN SPACE DEPEND UPON are EARTH'S feared by all fire fighters. SURFACE EACH DAY. Pr 1 TIME TIME AND SPACE A RAY OF LIGHT TRAVELING ARE NOT INHERENT MILES A WILL Water or ordinary chemicals If4,0o0 SECOND IN EXTERNAL NATURE. RETURN TO ITS STARTING POINT THEY LIE ENTIRELY IN IN are dangerous to 30, 000, 000 / THE MIND OF THE °(EARS iO ORSERVE' use and have no iL.1J effect on fire. A

TO OPERATI " T'0 'KNOW THE REAL WORLD TURN RED HOW "AcCORDIN4 To THESE KEEP WE MUST DISCARD APPEAR- THEORIES, THERE IS -,- EITIR ANCES WHICH ARE MERELY breaks electrical arcs A DEFINITE LIMIT To SUPER -ADDED BECAUSE of and extinguishes the THE PARTICULAR VIEW -POINT TIME AND SPAC'E OF THE TERRESTRIAL fire instantly. It can OBSERVER" be directed into elec- trical machinery without damage to apparatus or injury to operator. Write for DO- I MAKE Our Agency or Distributors Plan MYSELF ENTIRELY THE NU -EX FIRE APPLIANCE CO. CLEAR' ?" COLUMBUS, "`LES, INDEED, OHIO EXCEPT FOR ONE DEAFNESS IS MISERY 'THING - I know because I was Deaf and had Head Noises for over 30 years. My invisible Antiseptic Ear Drums restored my hearing and stopped Head STv Noises, and will do it for you. They are Tiny Megaphones. Cannot be seen when worn. Effec- five when Deafness is caused by Catarrh or by Perforated, Partially or Wholly Destroyed Natural Drums. Easy to put in, easy to take out. Are Unseen Comforts." Inexpensive. Write for Booklet and my sworn statement of how I recov- I ered my hearing. D A. O. LEONARD 41*j[I/4.1r Suite 369, 70 5th Avenue -- New York City Courtesy Illustrated Daily News You benefit by men Toning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 919

ANewidea that Makes Men Rich he used to hand us day in and day out. 'It must to a man's income is a mere nothing. That's merely done. You can do it. Get a grip on yourselves, playing at it. In one case I took a rank failure SEVEN men tried out this idea. Each was be as earning less than $40.00 a week in a boys. Throw your Will into action. Drive! Will- and in a few weeks had him earning as high routine position. To -day five of these power will carry you through.' $2,000 a week. Listen to this: I never took much stock in that Will talk A young man in the East had an article for men draw salaries ranging from $8,000 to -wide demand. For a year, the sixth is wealthy, and the those days. I thought it was just one of Zim's pet which there was a nation $40,000 theories. But now I see that Zim was right twelve years he "puttered around" with it- barely seventh is worth a half- million dollars. How - Then he read "Power of Will." they did it and how you, too, can duplicate wonderfully right. eking out a living. success. "The reason why our department always broke Today this young man is worth $200,000. He is their amazing records, and why every man in that department has building a $25,000 home -and paying cash for it. since made a big success is because Zim put the He has three automobiles. His children go to pri- drive into us-he taught us how to use our Will- vate schools. He goes hunting, fishing, traveling, OU men and women who are eager for success him. His income is could have been with me one power. That's what put us all where we are -the whenever the mood strikes -I wish you winning drive that comes from Will- power." over a thousand dollars a week. Y memorable evening last week. For then I bad In a little town in New York lives a man who spread before me seven of the most remarkable HEN you come right down to it the only two years ago was pitied by all yho knew him. cases of success of which I've ever heard. real difference between men is not birth nor From the time be was fourteen he bad worked and all came about in this way. At a convention W education nor luck, but Will-power. The suc- It slaved-and at sixty he was looked . upon as a in New York I met two old friends who had at one cessful man is successful because he knows how to failure. Without work, in debt to his charitable time worked for the same firm. use his Will. He compels suc- friends, with an invalid son to support, the outlook Each of these men had since won cess. The unsuccessful man is unsuccessful because he does not was pitchy black. About this time he ran across a remarkable success. As we sat in A Few copy of Power of Will." my room at the hotel, my two Examples know how to use his Will and is In two weeks he was in business for himself. and Gordon -got forced to meekly bow down to friends-Perry ' Personal Experiences In three years his plant was working night and day to talking about old times and circumstances. Not one man in fill During 1916 the profits were $20,000. Among over 350,000 users of a hundred knows how to use his to orders. the men they used to work with. "Tower of Will" are such men as During 1917 the profits ran close to $40,000. And The talk turned to what their Judge Ben B. Lindsay, Supreme Will. That is why more men are this genial 64- year -young man is enjoying pleasures former associates were doing Court Justice Parker, Wu Ting not successes. Nearly every suc- and comforts be little dreamed would ever be his. now. "Let's see," said Gordon, Fang, ex U. S. Chinese Ambassa- cessful man has a highly devel- "there's Bill Baley -now he's dor; Assistant Postmaster Britt; oped Will -the stronger the Will AMAZING things like these "Power of Will" vice -president of a bank at $10,- Gov. McKeivie of Nebraska; the greater the success. Natural has done for men and women in all walks of General Manager Christenson of to little un- 000 a year. Lawrence is general Wells -Fargo Express Co. ; E. St. ability amounts but life. There is no sound reason why it will manager of a machinery house at Elmo Lewis, former vice Pres. less backed by a dominant, com- not bring about the same surprising results for you. $18,000 a year. Yawman is foreign Art Metal Construction Co.; Gov. pelling, driving Will. You at least owe it to yourself to find out. And Sales Manager for an automobile Ferris of Michigan. and many The Will is the motive power I'm willing to prove it to you wholly at my expense. concern and makes $40,000 a others of equal prominence. of the brain. Without a highly - You can easily make thousands -you can't lose a $300 Profit From One trained, inflexible Will, a man year. Stanton is manager of the DaY's Reading cent. Here is my offer: - New York branch and last year "The result from one day's has about as much chance of at- Send no money -no, not a cent. Merely clip made in salary and commission study netted me $300 cash. I taining success in life as a loco- the coupon and mail it to me. By return mail over $28,000. Burton is in the think it a great book and would motive has of crossing the conti- you'll receive not a pamphlet, but the whole wholesale business for himself not be without it for ten times nent without steam. The biggest "secret" told in this wonderful book, "Power of and tells me that in the past the cost. " -A. W. Wilke, Faulk - ideas have no value without Will." up a ton, So. Dakota. Willpower to "put them over." Keep Look home. three years he has cleaned Worth $15,000 and More it five days. it over in your fortune. Even old Harry Carter, "The book has been worth more Yet the will, although heretofore Apply some of its simple teachings. If it doesn't whom everybody thought a dub, than $15,000 to me." -Oscar B. entirely neglected, can be trained show you how you can increase your income many is Secretary of a concern down Sheppard. 1917 E. Locust St.. into wonderful power like the times over -just as it has for thousands of others South and knocks out $8,000 a Decatur, IlL brain or memory. And by the mail the book back. You will be out nothing. - year. And Zimmerman, our old Would Be Worth $100,000 very same method - intelligent But if you feel that "Power of Will" will do for boss, is director of more con- "If I only had It when I was exercise and use. you what it has done for over a quarter of a million 20 years old, I would be worth cerns than I can think of and is $100,000 today. It is worth a If you held your arm in a others -if you feel as they do that it's the next rolling in money." hundred times the price. " -S. W. sling for two years it would be- greatest book to the Bible -send me only three and Taylor, The Santa Fe Ry, Mil - come powerless to lift a feather, a half dollars and you and I'll be square. "L`UNNY thing," said Perry, tans, Ter. from lack of user The same is If you pass this offer by, I'll be out only the j0 "every man who worked Salary Jumps from $150 true of the Will - it becomes small profit on a three and a half -dollar sale. But in that department under to $800 weak from lack of use. Because you -you may easily be out the difference between Zim has made a conspicuous suc- "Since I read 'Power of Will' we do not use our Wills properly what you're now making and an income several my salary has jumped from $150 -because we continually bow times as great. So you see lot cess. In the ordinary course of to $800 a month. " -J. F. Gibson, you've a -a whole events you'd naturally expect San Diego, Cal. down to circumstances -we be- lot -more to lose than I. Mail the coupon or one or two of the men to win From $100 to $3,000 a Month come unable to assert ourselves. write a letter now -you may never read this offer out while the others would plug "One of our boys who read What our Wills need is practice. again. along and never amount to any - 'Power of Will' before he came Develop your Will -power and over here jumped from $100 a thing unusual. But every one month to $3,000 the first month, money will flow in on you. Rich of these men has since made a and won a $250 prize for the best opportunities will open up for PELTON PUBLISHING CO. name for himself. I wonder if salesmanship in the state." - you. Driving energy you never it just happened or if there is a Private Leslie A. Still, A. E. F., dreamed you had will manifest 30 -A Wilcox Block Meriden, Conn. reason." France. itself. You will thrill with a new "I used to think about that a power -a power that nothing can lot myself," cut in Gordon, "and resist. You'll have an influence I believe I've found the answer. It's Zim, our over people that you never thought possible. PELTON PUBLISHING COMPANY, old chief. That's who we've all got to thank for Success -in whatever form you want it -will 30 -A Wilcox Block, Meriden, Conn. our success. come as easily as failure came before. And those "Remember what a slave driver we used to think are only a few of the things Will -power will do for You may send me "Power of Will" at your risk. him. When he wanted a thing done it had to be you. Just how to develop the Will into a mighty, done, done quickly and done right. He'd tell us irresistible force-how to make it do all these I agree to remit $3.50 or remail the book to you in some of the most impossible things, and he made things for you-is fully explained in that wonder- five days. us do them. Excuses didn't go. We nicknamed ful book "Power of Will." him 'Old Must.' Must do this -must do that. No Name excuses. Simply must do it. We knew it couldn't SOME of the things "Power of Will" has done for be done. Yet we got it done -always! people are astounding. I would hardly believe Address "We couldn't kick because he drove himself as them if I hadn't seen them with my own eyes. much as he drove us. Remember the line of talk Adding ten, twenty, thirty or forty dollars a week City rate You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 920 ELECTRICAL EXPERIMENTER January, 1920 MagnettIlc 5q0o mmo BATTERY CHARGIN By IPF('cpQa LIlndIleY Pyle PAYS BIG PROFITS (Continued from page 876) displays. At 8B Users Make $100to$350 Gear Profit EveryMonth such times conditions on the that moves when a current traverses NOW is the time to make BIG Profits in battery sun are no doubt such as to affect either the galvanometer is equipt charging. Cars are stored for winter with bat- directly or indirectly with a small teries to keep in condition. Who gets this big, the magnetic field of mirror. Within the black box is a strong money -making business? You or your com- petitor who is farsighted enough to install a source of light placed behind a pin- sturdy, reliable HB Battery Charger? Is it good hole. Light pacing thru pin business for you to pass by the opportunity to the -hole add $100 to $350 EXTRA PROFIT to your in- traverses the lens shown in the photograph, come every month? Start NOW to get those big falls upon the battery charging profits. It costs only 10e to galvanometer mirror and is 15c each to charge batteries-customer paya 75o reflected to a revolving cylinder D, to $1.50. BB Chargers are sturdy, dependable driven by and absolutely reliable. No expensive renewals or clock -work and covered with photographic repairs. Big, quick, clean profits, easily made. bromide CHOOSE paper. One has in fact upon the THE SIZE YOU NEED paper the bright image of the illuminated HB 500 -Watt Charger pin -hole. In practise Recharges 1 to 8 6- the cylinder with its volt batteries or their light- sensitive paper is protected from any equivalent at a time. Furnished complete stray light by a cover equipt with a narrow with clear, black elec- slit thru which the light trical, slate switch- enters to fall upon board, with mountings the moving paper. Subsequent chemical of ammeter, field rheo- stat, voltage lamp, two development of the paper yields a perma- controlling switches. A nent record of the behavior of the beam big money -maker for a battery business. of light, which wags to and fro in accord- small /-A E ance with the behavior of the galvanome- $15.00 Cash; Balance on Easy Monthly Terms ter mirror. In accordance with Fara- HB 16 -Battery Charger Apparatus Used In Recording "Magnetic Recharges 1 to 16 6 -volt Storms." Suspended day's laws of induced currents there is an batteries at once or their Coil of Wire, W; Mir- equivalent in 12 or 24 -volt ror, M, Attached to W. electromotive force induced in the coil batteries. Furnished com- which is proportoinal at any instant to the plete with 2 independent charging panels, each with the earth. Direct evidence of this was rate of change of the number of lines of a capacity of 8 batteries. obtained August 3, 1872, when Young, at the earth's magnetic field linking with the A splendid machine for a live, energetic garage Sherman, Idaho, ob- owner wishing to get big served profits. a solar outburst Small Cash Payment, Balance during an eclipse of the on Easy Monthly Terms sun. At the same in- HB 32- Battery stant magnetic observa- Charger i tories in England record- Recharges 1 to 32 6- ed magnetic disturban- volt batteries or equivalent at a time. ces. On the other hand Four separate charg- MEE= ing lines, each cap- Professor Francis E. able of charging up Nipher, the American in- to 8 batteries. Ideal equipment for big garage vestigator and scientist, or battery service station. Will has noted "magnetic ef- . Ó mouth d ar MI porrofit. fects" arising from pure- ly local weather condi- NB ININ Small Cash Payment, Balance on Easy Monthly Terms tions. NMI a Sold oo Trial Under HB Absolute Money -Back Guarantee MIMI All HB Equipment's sold anderem absolute gu nteerof To obtain an auto- complete satisfaction. You run no risks. if notsatis íibd Inn II Il 1 111111111111111 after tieing any HB Equipment 10 days. you may return it matic registration of the and receive all you paid us. The HB monthly payment plan is an additional guarantee. irregular and continuous Select the Charger You Need. Check the Coupon Below. Mark on this cou the HB Charger you are interested changes occurring in the Tear it out and mail TODAY. Be the first in your town earth's magnetic toin. have an HB Charger. Don't delay. Act now. field, the writer assembled the wwww TEAR OFF HERE . . .5-30 HO ARTBROpB S.COBo 17E TROY. OHIO the apparatus photo- S'00 -So me about HB equipment checked fig. 8 below, and tell me about the HB Money-Back Guarantee graphed and EE and Trial plan: diagrammed ..HB 8 -Battery Charger HB Belted Charger in Figs. 1 and 1 -A. A ..HB I6- Battery Charger (Used where electric cur- simple A Wonderful Record of a Magnetic Storm Due to the "Sun- .. HB 32- Battery Charger rent is not available.) coil of wire C, is Set" Effect. laid upon a table and its Your Name terminals are connected Address State to a sensitive coil. Consequently every change in the electric indicator, or galvanometer. See earth's magnetic field is accompanied by a Fig. 1 -A. That part of the galvanometer current flow thru the galvanometer and a motion of the spot of light on the moving paper. No doubt the fluctuations recorded in Fig. 2 are in large part due to effects of electric car lines about 71X1 feet distant Be a Doctor of Chiropractic from the appáratus. In. certain work by the U. S. Government car effects have The greatest professional opportunity been noted at a distance of 13 miles from the car lines. This method of registration today, for the following reasons: of magnetic storms is not iew. It was first put into 'practise in a certain Polar 1.-The demand for practitioners is greater than the supply. 2.-The profession is not overcrowded nor will it be for years to come. 3.- Greater financial returns because of greater service to the public. 4. -It is attracting the support of the most intelligent people because it is based upon scientific knowledge of the human body both in health and in disease. Because we invite 5.- investigation for every statement we make and extend PORTO RICO the privilege of a personal visit to our classes to permit you to form your MARCH 14,1913 own opinion as to the training you receive here. ¡HI i Midwinter enrollment. Special inducements for enrollment in this class. Write or call for particulars at once, as this opportunity will fig. 3 Ee not last long Portion of Automatic Record of a "Magnetic Storm" of 98 Hours' Duration, Taken at Vie- New York College of Chiropractic ques, Porto. Rico. Dr. M. CARNOT, President Expedition of 1882 -83, when a single insu- WRITE FOR BOOKLET X lated wire was laid out upon, the polar ice 1416 Broadway, cor. 39th St., N. Y. C. to enclose an area of approximately three Bryant 6956 -6957 square miles. The Einthoven type of gal- vanometer is the best type to use in corf- (Conttnued on page 922) you benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 921 New Method Makes Music Amazingly Easy to Learn Learn to Play or Sing in Spare Time at Home. Every No "trick" music, no "numbers," no Step Made Simple as A B C by Print-and- Picture makeshifts of any kind. Lessons That You Can't Go Wrong On. I call my method "new" - simply because it is so radically different from the old and hard -to- understand TRY IT ON APPROVAL. 1; ways of teaching music. But my \\, method is thoroughly time -tried and Entire Cost Only a Few Cents a Lesson - and proven. Over 225,000 successful Nothing Whatever to Pay Unless pupils -in all parts of the world, and You Are Satisfied. including all ages from boys and girls of 7 to 8 to men and women of 70-are the proof. How often have you wished that you knew how to Read the enthusiastic letters from some of them, which play the violin or piano -or whatever your favorite in- you will find printed at the right -samples of the kind strument may be-or that you could take part in singing? of letters I am receiving in practically every mail. My How many an evening's pleasure has been utterly file contains thousands of such letters. Largely through spoiled and ruined by the admission "I can't sing," or the recommendations of satisfied pupils, I have built up "No, I am sorry, but I can't play." the largest school of music in the world. At all social gatherings, some one is sooner or later sure But I don't ask you to judge my methods by what to suggest music. When the others gather around for others say or by what I myself say. You can take any the fun, the one who can take no part feels hopelessly course on trial- singing or any instrument you prefer out of it-a wall flower-a mere listener -and judge entirely by your own pro- and looker on! gress. If for any reason you are not Or those long and lonesome evenings at Learn to Play by Note satisfied with the course or with what like hours you learn from it, then it won't cost you home, when minutes seem -how For B eginners or quickly the time would pass if you could Adva nced Pupils a single penny. I guarantee satisfaction. spend it at the piano or organ -or in mak- Piano Harmony and On the other hand, if you are pleased ing a violin "talk," or in enjoying some Organ Composition with the course, the other instrument. Violin Sight Singing total cost amounts to and Viola Guitar only a few cents a And now -at last -this pleasure Banjo Ukelele SUCCESS satisfaction that you have so often wished Tenor Banj o Hawaiian lesson, with your "Since I've been taking for can easily be added to your daily life. Mandolin Steel Guitar music and every- your lessons I've made over $60 with my vio- No need to join a class or pin yourself Clarinet Harp thing also included. lin. Your lessons surely Flute Cornet When learning to are fine. " -Melvin down to certain hours for lessons or prac- Saxophone Piccolo Freeland, Macopin, N. J. need pay a dollar or more per play or sing is so tice. No to Cello Trombone "When I started with to private teacher. Neither the easy, why continue you I knew nothing lesson a about the Cornet or mu- of time nor expense is any longer to confine your en- sic, but now I can play question almost any piece of mu- obstacles that have been confining joyment of music to mere listening? sic. "-Basson Swan, a bar -every one of the Denmark, Col. Co., No- your enjoyment to mere listening have now been removed. Why not at least let me send you va Scotia. my My method of teaching music by mail -in your spare free book that tells you all "I want to extend the ? heartiest approval of time at home, with no strangers around to embarrass you about my methods I know you your Piano Course. It will find this book has done more for me -makes it amazingly easy to learn to sing by note or to absorbingly than years of other les - sons. " -Moaie N. play any instrument. interesting, simply because it shows Lewis, 319 Jefferson, Neosho, Mo. You don't need to know the first thing about music to you how . easy it is to turn your wish to play or sing into an actual "The folks at home are begin -don't need to know one note from delighted to hear me fact. Just now I am making a play the Organ so well. another. My method takes out all the hard You have a wonderful all the. difficulties special short -time offer that cuts system of teaching mu- part - overcomes - sic. - M. F. Allard. makes your progress easy, rapid and sure. the cost per lesson in two -send Caraquet, N. B. Whether for an advanced pupil or a your name now, before this special beginner, my method is a revolutionary offer is withdrawn. No obligation- improvement over the old methods used simply use the coupon or send your name and by private teachers. The lessons I send address in a letter or on a postcard. Instru- // Mr you explain every point and show every ments supplied when needed, cash or credit. // F. Kemp form / President step in simple Print -and -Picture / U. S. School that you can't go wrong on -every step / of Music, 1331 is made as clear as A B C. My method makes each step / Brunswick Bldg., so easy to understand and practice that even children U. S. / New York City, / Please send me your only 7 to 10 years old have quickly become accomplished / free book, "Music Les- / sons in Your Own Home," players or singers under my direction by mail. Also School of Music / and particulars of your Spe- thousands of men and women 50 to 70 years / cial Offer. old- including many who had never before 1331 Brunswick Bld g, / tried to play any instrument or taken a / Name lesson of any kind -have found my method New York / equally easy. My method is as thorough / / Address as it is easy. I teach you the only right / way -teach you to play or sing by note. / /City Siate You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 922 ELECTRICAL EXPERIMENTER January, 1920

Magnetic Storms Make s2,50 o (Continued from page 920)

nection with the test coil, since the moving 1ar part consists of but, a single, very thin con- s4,000 in ducting filament stretched across the gap of a powerful magnet. The filament being ..iäPSuRaER7 e

Cheltenham, kid. hoy 6; /902

I t t I t t t I h 15,000 t Morne KiÏes, / 2 .3 4 s -6 7 8 9 Mid't. Fig. 4 To Old Tires EE Record Taken in Maryland of Magnetic Dis- Stations Needed Everywhere turbance that Accompanied the Eruption of You know what 4,000 to 5,000 additional tire mileage Earns $800 Month Mt. Pelée, Martinique, in 1902. means to motorists. Haywood's Tire Surgery is a new tire repair method that gives new life and thou- This is so light follows accurately even extraordi- sands of miles of additional service to tires which before would E. T. narily rapid variations in the earth's field. be thrown in the junk.pile. Think of what this means, man, as Buchmann Fig. 3 is a portion of an record a money making opportunity. Think of the business that is automatic going begging to pay you big money if you're ready to act. He is a Tire of a "Magnetic Storm" of 98 hours' dura- Surgeon tion taken at the Magnetic 'tom°° °'S a t Observatory at Chicago. He Vieques, Porto Rico, March 14, 1913. Is a says: "Am This earning record differs from that of Fig. 2 in that Wonderful Business $800.00 per it is a record obtained from a mirror at- 4i month, and Easy to Learn -No Experience Necessary tached directly to a suspended magnetic / confining needle arranged to move under the varying Uncountable millions of tires are cut, torn, gashed and bruised, myself solely to re-build- broken down. worn out, yet with the Haywood method of tire ing of Tires by Haywood pull of the earth's field. Also it differs in surgery all these tires, no matter how far gone, can be put back Method." the rate of motion of the recording paper, into service. Every town, every hamlet, every city needs being only about one- thousandth the Haywood Tire Surgeons, and it's that we are offering you - $6,500.00 Home Paid For rate a business of your own -a business that is already making used in the case of Fig. 2. hundreds of John W. Blair Toledo. men rich and so will make you. Ohio says: ' ?When I YOU CAN LEARN IN A WEEK. Walk right into $2500 to started three years ago, I $4000 a year -be independent in business for your- had just $50.00 left after self. Let us send you all the facts. paying for my outfit. I now have a $6,500.00 Mail Coupon - Get My Free Book home paid for, $1,000.00 Just,put your name and address on in one bank, and de- the coupon be- posits RE!II=Min low, send it to me by return mail, and I'll send you in several others." w1rmII>1 without obligation full particulars of this money rYUr`n111r.f lV making opportunity. My Free Book explains everything. Tells how to start business with very little money. Now you can easily and quickly learn all about tires and my method of Tire Surgery. It will tell you how to handle every detail of the business. In fact, how to succeed and make money. Don't wait. Write me today. The postage for a stamp or poet card will prove I- /0 / O / 30 the best investment you ever made. Fig. 5 et M. HAYWOOD, President iui s HAYWOOD TIRE & EQUIPMENT COMPANY 1209 Record Taken by Prof. Nipher of a Magnetic CAPITAL AVENUE INDIANAPOLIS, INDIANA Disturbance Arising from a Violent Squall of Mail To -day For Wind. "ii Facts VOLCANIC ERUPTION M. HAYWOO D, President CAUSED MAGNETIC HAIrWOOD TIRE & EQUIPMENT COMPANY DISTURBANCE 1209 Capitol Avenue, Indianapolis, Indiana Fig. 4 is a careful copy of an automatic Dear Sir -Send me quick. without obligation, full particulars of Tire Surgery. record taken at the U. S. Magnetic Observ- Name atory at Cheltenham, Md., May 8, 1902. It Address records the magnetic disturbance that ac- companied the eruption of Mt. Pelée, Mar- tinique (see arrow). This magnetic dis- OPEN A TIRE REPAIRING SHOP ! ! turbance was recorded simultaneously at Cheltenham and at Baldwin, Kansas, and BUSINESS GOOD AND FAST GROWING occurred as nearly as could be determined simultaneously with the eruption. This TA' ., VANDERPOOL VULCANIZER (5 Cavity), has capacity of $ 100 worth of work a day. We disturbance was purely a magnetic one and are the pioneers in the manufacture of the Dry not a mechanical one due to any transmitted HMDENPOOLSPHINaFiÉlo.ör.,r? Cure Vulcanizer. earthquake shock. With the VANDERPOOL VULCANIZER no ex- ; perience is necessary. We give you free in- 411 414 structions. Write today for FREE TIRE RE- PAIRING MANUAL and full particulars. If r, others can be successful, so can you be. Write today. INN al 1 In answering address Dept. R. 20 lh =M1111= WM. VANDERPOOL CO., - - Springfield, O. IW 11nlCl:::::°: : "The Eastern" is a Large Achromatic Telescope III BIVI I1I1II,1 YOU WANT i illl'I WHAT ONLY MADE UPON NEW imIIIIAempa\!s illlST 'ZY2FEÉT SCIENTIFIC PRINCIPLES. Positively such a good Telescope was IIIIIIII\/1 OVER never LONG 9 SCENTS Sold for this price before. Eastern Telescopes ON SEA / are made by one of the largest manufacturers FARN RANCd 1II11I pR of telescopes in America: we control entire production; measure closed 9 Inchss and open over 3 feet in ! sections. They are nicely brass bound, with I Every sojourner scientifically ground lenses. Guaranteed by the maker. in lee country or at the seaside as I1_ resorts should certainly secure one of these instruments, and no farmer should be srithout one. The scenery just now Is beautiful. a Telescope will aid you in taking views. Oblong are brought to view with astonishing 1MIS fig. 6 clearness. Sent by mail or express, safely packed, prepaid, for only 99 cents. Our new Catalogue of Watches, etc., sent wit II each order. This Is a grand offer and you should not miss it. We warrant each telescope just as represented or money refunded. Send 99 cents by Recistered Let ter, Post Office Money Order, Express Money Magnetic Disturbance Produced by Sunlight Order. or Bank Draft payable to our order. or your newsdealer or si ore-keeper will order one for you. Whether Shining Thru Rainfall; After a Record by C000umer or d. r send cash wit order. To dealers 6 for Four Dollars. Prof. Nipher. EASTERN NOVELTY CO., 67: 172 E. 93d STREET, NEW YORK. January, 1920 ELECTRICAL EXPERIMENTER 923

The greater part of our magnetic storms come from causes outside the earth's crust. Recent researches by Professor Nipher Learn Mechanical Drafting have extended markedly our knowledge of the origin of disturbances imprest upon the Earn $35 to $100 a Week

"Get into the profession of big pay and Rapid Advancement with the help of the school that has started hundreds on the Road to Success. I am ready to help you." Roy C. v Claflin, President, Co- lumbia School of Drafting. s Fig 7

I lustrating the Effect Upon the Strength of the Earth's Magnetic Field of a Large, Dense and Sharply Defined Cloud Passing over the Sun.

earth's magnetic field. In a series of im- portant papers publisht by the Academy of Science of St. Louis, Professor Nipher has shown conclusively that magnetic storms may arise from wind effects, rain storms, Learn at Home and cloud shadows. He has produced magnetic effects from flames and explosions in Spare Time and has observed magnetic effects due to sounds. You don't have to stop work or leave A WIND SQUALL CAUSES "MAGNETIC home in order to become a trained STORM" Draftsman. Through our practical Fig. 5 is one of Prof. Nipher's records Home Study Training we teach you in of a magnetic disturbance arising from a your own home, and enable you to violent squall of wind. The beginning of qualify as a practical Draftsman. disturbances was noted nine minutes before The Demand is Greater the wind squall reached the observing sta- Than the Supply No Previous Training The demand for properly trained Draftsmen has always been greater than the supply, but Required this is more so today than ever before, owing to greatly increased construction and mechan- Owing to the comprehensive nature of ical development. The Draftsman is an es- our course, you need no previous train- sential connecting link in all engineering in you have work. This great demand is indicated by the ing the subject. Though long lists of want ads for Draftsmen in the r^ never done any kind of drawing before, daily papers, especially those of industrial you can become a thorough Draftsman centers. n by following our instructions. Specialists in Mechanical Can Learn in Short Time Drafting The COLUMBIA SCHOOL OF DRAFTING by Our Methods not only trains Draftsmen by mail but also Fig .9 maintains a large local institution of the The reason for this is that we elimi- highest standing. For many years it has been nate unnecessary theoretical work and the leader in SPECIALIZING on the teach- Record Produced by a Flame Creating a ing of DRAFTING. This is an obvious ad- Magnetic Disturbance Close to the Recording concentrate upon the PRACTICAL vantage over teaching Drafting only as a side Station. problems such as confront the profes- issue. sional Draftsman. We do not require tion (time of arrival indicated by the ar- you to spend months of your time on Drawing Outfit Furnished row) and the disturbances continued for but you on "preliminary" work, start We supply all our students with a drafting eight minutes after the squall had past the REAL DRAFTING at once. That is outfit for use throughout the course. There station. Quoting from one of the original one reason why our students "make is no extra charge for this, and it becomes papers,-"When small clouds are scattered good" so readily. your personal property when the course has over the sky and a local fall of rain occurs been paid for in full. at the observing station, the sunlight pass- ing thru the air, thru which the rain drops Our Graduates Get to the Book of Particulars Sent fall, a very marked magnetic storm is pro- FREE duced." Such a disturbance is reproduced Top If you are interested in becoming a practical in Fig. 6. Fig. 7 represents the effect upon The universal success of our graduates as Draftsman through the thorough training of the strength of the earth's magnetic field Professional Draftsmen, many of whom have the COLUMBIA SCHOOL OF DRAFTING, of a large, dense, and sharply defined cloud advanced rapidly to positions of Chief Drafts- whereby you can enter a Profession in which men, is evidence of the REAL VALUE of your services will always be in demand, you passing over the sun. The sun disappeared the training given by the COLUMBIA are invited to write us for our free book of at 4:20 Sand reappeared at 4:28,- indicated SCHOOL OF DRAFTING. Large numbers particulars, which describes our school and of our students have secured excellent posi- methods. For your convenience you can fill Vite tions even before completing their courses. out and We gladly cooperate with our students and graduates in securing desirable positions, which has been easy for us owing to the many Mail This Coupon To -day demands upon us to supply our "product" for these positions. COLUMBIA SCHOOL OF DRAFTING, -14th & T Sts., N.W., Dept. 1075, Draftsmen Get $35 to $100 Washington, D. C. Without obligation to me, please send me full particulars of your practical home study a Week training in Drafting. Our graduates have shown their ability to reach high salaries RAPIDLY, owing to their practical training. They secure excellent Name si salaries AT THE START, as high as $2,000 fig. /o ee a year. The usual pay of Draftsmen is $35 Address to $100 a week. The Magnetic Effect of an Explosion of 21 Sticks of Dynamite, 200 Feet North of the City State Observing Station. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 924 ELECTRICAL EXPERIMENTER January, 1920

by the arrows. Eclipse shadows produce similar results. Fig. 8 shows the magnetic storm due to the "sun -set" effect. It thus appears that the earth's shadow at night has the same effect upon the earth's magnetic field that a cloud shadow has during the day. Fig. 9 is a record of the magnetic effect of a flame produced close to the ob- serving station by the burning of 25 or 30 pounds of black powder, spread uniformly over a platform of 20 square feet area. There is in this case no explosive effect. Fig. 10 records the Magnetic effect of an explosion of 21 sticks of dynamite 200 feet north of the observing station. Fig. 11 represents the magnetic effect of disturb- ances set up by sound waves, emitted by a fog -horn several thousand feet distant from the station. Professor Nipher states that his re- searches have establisht beyond any ques- tion that local variations in the earth's magnetic field are determined wholy by local weather conditions. He concludes that the great majority of magnetic dis- turbances may be traced to variations in the magnetic permeability of the atmos- phere,'arising from changing conditions in the ionized air. That the subject of Terrestrial Magnet- ism is of paramount practical and theoreti- cal interest and importance is .evidenced by Where Upkeep Counts Most the large number of magnetic observatories maintained by the leading governments of the world, and by the immense amount of Twelve million miles of wire, work the lessening of efficiency work being carried on in the conduction of magnetic surveys on land and sea. Our connecting cities, villages, farms; means merely the lessening of own Department of Commerce, thru the running under United States Coast and Geodetic Survey, busy streets and service; but with the telephone, continually publishes a large amount of across trackless prairies; these mechanical and electrical con- material. An extensive bibliography of the are the Bell Telephone's avenues ditions must be practically per- of speech. fect to insure operation.

These twelve million miles of The most delicate electrical wire, throughout every foot of currents in use are those of the their length, must be kept elec- telephone, and inspection must !0 r trically capable. be ceaseless that the lines may- Magnetic Disturbance Set Up by Sound Waves Emitted by a Fog -horn Several Thou- sand Feet Distant from the Observing Sta- be kept in constant readiness. tion. A few drops of water within subject may be found in an international a cable may cut off a thousand These conditions and costs quarterly journal publisht under the name "Terrestrial Magnetism and Atmospheric subscribers. A line snapped by must be met to provide this high Electricity," by the Department of Terres- trial Magnetism of the Carnegie Institution storm may isolate a district. A standard of service needed and of Washington, D. C. wet leaf touching a wire may by the demanded American WHAT ONE RESEARCH LABORA- stop service. In most kinds of people. TORY DID. In the research laboratories of a large American electrical manufacturing con- cern are many scientists working to in- AMERICAN TELEPHONE AND TELEGRAPH COMPANY crease the usefulness of electricity to in- AND ASSOCIATED COMPANIES dustry. In one of these laboratories at Schenec- tady are nearly 70,000 square feet of floor One Policy One System Universal Service space, with each room piped for water, gas, compressed air, vacuum, high and low pres- sure hydrogen, oxygen and high pressure steam, and adjoining are completely manned and equipt machine and forge BATTERY CHARGED AT HOME shops, etc. COLD WEATHER WON'T BOTHER YOUR STARTER In this laboratory research work has and your battery will last years longer if kept fully charged with the been done on paints, oils and varnishes ; F -F BATTERY BOOSTER irons, steels and alloys ; copper, zinc, The new size 6 Ampere $15.00 F -F Bantam Battery Booster charges a 6 Volt battery efficiently from 110 Volt 60 Cycle A. C. current. Attaches to any lamp socket and costs no more for current than molybdenum and magnesium; kenotrons burning a lamp. Battery is left right in car without disconnecting and and pliotrons for radio work ; X -ray loca- charged over night unattended. New 5 Ampere 12 Volt Bantam at $20.00. tion of holes in castings ; incandescent lamps and searchlights; insulation and For parcel post add postage and Send check for express shipment. compounds ; turbine blades and boiler insurance to cover shipping weight of 15 pounds. Ask for bulletin 12 brush describing this and other F -F charging apparatus of larger capacities AND UP feed water ; atomic hydrogen ; molecular including those operating on farm lighting plants, etc. layers in catalyzers ; fuse fillers ; lithium, Write for Bulletin No. 12 boron, uranium and thorium ; rubber and platinum substitutes, sherardizing and val- THE FRANCE MANUFACTURING CO., Cleveland, Ohio orizing, condenser, boiler and pyrometer tubes and powerful X -ray tubes. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 925 The Ammteu NAME POSITION SALARY AUTOMOBILE By JOSEPH H. KRAUS (Continued from page 896) ENGINEER ordinary blank cartridge, mounted on the REPAIR MAN base, at one end. A steel plunger, which is free to slide between two bearings ; has been sharpened at one end (the end which CHAUFFEUR sets off the cartíidge), and has a notch filed in the other end. This notch is filed in the rod in such a way that a small, flat piece of brass (also placed in a bearing of its own) will hold the rod back until it is ready to be discharged. In other words it acts as a trigger. Around the rod is coiled a stiff piece of steel or better still, a Put Your Name steel spring. A flat piece of metal is then adjusted to the rod to hold the spring in place ; it being held at the other extremity by the bearing. A glance at the accom- fix things -Roll panying sketch and photos will On This Pay in your mind. clearly Men like you are wanted for big -pay positions in the fascinating field of "To the trigger is attached a piece of engineering. have made it easy for you to fit yourself for one strong silk. This is led out thru a tiny automobile We hole in the side of the bowl made for that of these positions. You don't have to go to school. You don't have to serve purpose, passing thru two holes in the an apprenticeship. Fifteen automobile engineers and specialists have compiled small one -quarter inch legs. It is then a spare -time reading course that will equip you to be an automobile expert fastened to a button on the other side of taking any time from your present work. the bowl. without "Before commencing the trick, a blank Partial List of cartridge is prepared by first removing the Contents More than 100 blue hard cardboard in the end of the shell. AUTO BOOKS prints of wiring diagrams Explosion Motors Welding 6 Volumes Shipped Free Motor Construction and Repair Carburetors and Set- Now ready for you -an up -to- the -minute six -volume tings library on Automobile Engineering, covering the con- Valves, Cooling Lubrication struction, care and repair of pleasure cars, motor trucks Fly -Wheels in- Clutch and motorcycles. Brimming over with advanced Transmission formation on Lighting Systems, Garage Design and Final Drive Steering Frames Equipment, Welding and other repair methods. Con- Tires or an engineer or a Vulcanizing tains everything that a mechanic Ignition motorcyclist or the owner or prospective owner of a Starting and Lighting Systems motor car ought to know. Written in simple language Shop Kinks Tastefully bound in Commercial Garage that anybody can understand. Design and Equipment American Morocco, flexible covers, gold stamped, 2,650 Electrics Storage Batteries pages and 2,100 illustrations, tables and explanatory dia- Care and Repair grams. A library that cost thousands of dollars, to com- Motorcycles Detail of the "Fire -Bowl" Trick, Showing Commercial Trucks How the Flowers Are Concealed in a False pile but that comes to you free for 7 days' examination. Glossary Compartment Not a cent to pay in advance. First you see the This is replaced with tissue paper after the Only 7c a Day books in your own home or shop. Just mail powder has been loosened. It is then in- coupon and pay express charges when books arrive. You can read them and study them serted into the holder, the spring pulled for seven whole days before you decide whether you want to keep them or not. If you back, and the trigger set. The cotton in like the books send only $2 in seven days and $2 a month until the special introductory the bowl is now saturated with alcohol and price of $19.80 has been paid. (Regular price $30.00.) Along with the set goes a year's sprinkled with ordinary salt (sodium chlo- consulting membership in the American Technical Society. (Regular price $12.) This rid). This gives a pretty yellowish tint to great bargain offer must soon be withdrawn. the flames, after the production of the fire bowl. The bowl is now placed in a ver- tical position, and the well in the center be No Money Now filled with alcohol so that there will Send enough alcohol left to burn for quite some Don't take our word for it. See the books without cost. There is so much profit in this time. offer for you, that we urge you to waste not a moment in sending for the books. Put the coupon in the mails today. "When the bowl is presented, it is then Send no money -only the coupon! only necessary to pull on the string which releases the firing pin; this in turn explodes the cartridge, the latter not going off with American Technical Society a report -but burning like a slow flashlight Dept. A251, Chicago, Ill. powder. When this occurs, the cotton im- pregnated with alcohol and salt is set on __s,____as,_s,__ fire and burns as you have just seen." American Technical Society, Dept. A25l. "Yes, but how about the flowers ?" I in- 1 Chicago, III. Please send me the 6- volume set, Automobile tervened. Engineering. for 7 days' examination, shipping I charges collect. If I decide to buy, I will send FREE! month "We are just coming to that. The top set is included- $2 days and balance With every until the $19.80 has been pald.. Then is up seemingly of FREE-a Consulting Mem- set of books as you will note made bership which gives you the me a receipt showing that the $30.00 and the $12 Consulting Membership are mine and one piece but in reality two. Inside the privilege of submitting your I fully paid for. If I think I can get along with- false top are arranged large quantities of perplexing problems to a out the books after the seven days' trial I will corps of experts for an en- at your expense. silk flowers, each of which has a spring tire year. This Consulting I return them Membership regularly sells inside of it so as to insure perfect opening for $12.00. I Name the moment they are released. This effect is obtaind by placing the two tops on the I Address Reference You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 926 ELECTRICAL EXPERIMENTER January, 1920 bowl together. (They being held so by a hook -like affair which passes thru the bottom plate in a slot made for it, and held there by giving it a slight turn.) On removing it again only one top is taken away, thus giving rise to the rush of flowers. "Here are a few photographs which will help make it clear, you may take them if it will help any." Auto\wheel Thus concluded the magician's discourse on his Fire -Bowl mystery. AN INTERESTING CARD TRICK. The Universal Pack: A pack of cards similar to that made by any leading magic giee!Jlin'I sheA Peach? supply house, which is universal in its use and the fake not easily detected, is made -that's what your gang'll very simply. Take a deck of cards (a say if you win the prize. We'll tell the names of winners straight deck), which has a plain back, in in February. The names and ad- other words, a back which lacks a margin. dresses of fellows who won prizes These are clamped rigidly between two for giving the best uses for the OVER 50,000 ambitious men and blocks of wood, the latter having been women have secured better posi- shaved down so as to be quite smooth and tAvoNateVmske tions as a result of this course. the cards and wood all flushed together at AND THE Noted professors have specially pre- one edge. A file is now past over the oAuto-Wh pared the lessons for home study and eads%í[ - edge shaving in this way the cards and Maybe your name will be there. it can be completed within two years. wood at the same time, thus preventing any Better watch. Thousands of fellows and covers all require- entered the contest and the judges It is complete marring or turned edges. Some very fine had a hard time picking the win- ments for entrance to college, civil serv- ners. They promised to let us know sand paper is now applied to the edge, fin- in time to tell you in February. ice positions and the leading professions. ishing the job smoothly. The cards may You can master every lesson without project at one end and be filed off. More Prizes Coming trouble. Just one or two hours a day - Now. if you or any of your gang you will be men- It will be noted that all the cards are did notwin you have another chance your spare time -and coming. We're going to have a tally equipping yourself for the position narrower at one end than at the other, but series of contests this year -just you want. Without a High School train- only slightly so,. thus making detection al- the kind of contests you follows most impossible. The cards are then shuf- will like. ing you are badly handicapped. You And say - the prizes you can win will make the other can't afford to overlook this essential fled and presented to the victim, who draws fellows say - "Ain't She a Peach ?" Keep your eyes open looks at and for these new contests. Send for our Monthly Magazine. and fundamental education -not if you one, it replaces it in the pack, You will like it. It is full of contest news -how to get in whence they are shuffled again. During on Auto-Wheel contests, with suggestions to help you win. wish to succeed. Just give the names of three coaster dealers in your town the operation, however, the performer re- and'state which one handles the Auto-Wheel. Then we'll Satisfaction Guaranteed verses the deck in his hand and when the send the Magazine and a FREE FELT PENNANT. Also the story about organizing an Auto-Wheel Club -with So that you may see for yourself how thorough card is replaced, it is only necessary to FREE CAPS for all members. and complete our training is- whether in our pass the fingers High School or any of our practical courses along the edges of the Buffalo - cards, when one card, the card chosen will Sled Co., 163 Schenck Street, we invite you to take TEN LESSONS before you In Canada: Preston, Ont. N. Tonawanda, N. decide whether you wish to continue. After the be withdrawn, due to the fact that it is Y. completion of ten examinations you have only to tell us you are dissatisfied with our course wider than the rest of the deck, it having and your money will be refunded in full. You run been replaced in the reversed position. It PLANE no risk-so check and mail the coupon for a Free is then brought to the top and may be pre- GLIDE "O" Bulletin. We employ no agents, so don't hesitate, sented in any way thought desirable. // // /// Learn the principles of American School of Correspondence Likewise, all four aces may be inserted Aviation by into the pack, reversed - rrNDept. H -261 Chicago, U. S. A. of course, and corn Hying o u r pletely shuffled, and with one cut may be 3No famous glide O plane. Not brought to the top and dealt off. The pack a toy, but a scientifically con- Explain how I can qualify can also be divided into red cards and structed gliding model, which may for the position checked. black cards, with one cut in this case ; all be thrown by hand on the field High School Graduate Lawyer the red cards should reversed or launched from the top of the Electrical Engineer Business Manager be before hill. Will circle, loop and glide Electric Light and Power Certified Pub. Ace'nt commencing the trick. After shuffling gracefully with a light throw. Superintendent Accountant and Auditor _Hydroelectric Engineer Bookkeeper thoroly the performer runs his fingers Constructed of best materials, Telephone Engineer Stenographer along the edge of the cards several times finished in Bright colors with the insignia ....Telegraph Engineer Fire Insurance Expert of the U. S. Army on the Main Plane. Wireless Operator Sanitary Engineer to insure perfect separation, and then with Very durable and easy to fly. All wood, ad- Architect Master Plumber is justable. Price 55c Postpaid in U. S. Send for ....Building Contractor Heating and Ventilating one cut he able to divide the "reds" ....Civil Engineer Engineer from the "blacks ". catalogue H3. Structural Engineer Automobile Engineer HEC Aeroplane Co., 345 E. 49th St., New York City Mechanical Engineer Automobile Repairman Countless other stunts may be performed .....Shop Superintendent Airplane Mechanic Steam Engineer Gen'! Education Courses in a similar manner, taking advantage of Draftsman and Designer Common School Branches this prepared deck. (The next paper will appear in an early Name issue.) Send for This Book Wrests of Model Aeroplanes Teils how yoñ can build and fly accurate, re- SICKNESS OF THE ADRIATIC. duced -scale Models of real Aeroplanes; I)t: THROW YOUR VOICE HAVtLAND Battle Plane. NC -4 and others. You Under the table, into a can build one easily. Send 10c in stamps NOW trunk, down Cellar or "Sickness of the Adriatic" is the name and get this 48 -page book. Plans anywhere. Our lessons for Model Aeroplanes -NC -4, 50e; given to the phenomenon of luminosity DE HAVILAND Battle Plane, in VENTRILOQUISM Curtiss Military Tractor. Bleriof teaches you. With our frequently observed in the Adriatic Sea. Monoplane, Nieuport Monoplane, At times its waters become phosphorescent Taube Monoplane, 35o each; VENTRILO and give beautiful reflections. Cecil Paoli Champion Racer, 25c. (fits in the mouth and SEND FOR PLA NS OR BOOK TODAY cannot be seen) you The seas around China and the Indian IDEAL AIRPLANE & imitate Birds, Ani- Ocean offer fascinating spectacles of the SUPPLY COMPANY mals, etc. without same character. Making Model Aeroplanes Since 5811 moving your lips. 159 -161 Wooster St., Cor. W. This outfit and book of This liquid phosphorescence is truly bio- JOKES by mail for 10e. Houston St., New York ARDEE CO., luminescence. It is caused by a tiny pro- Dept. 25, Stamford, Ct.t tozoa, a species of fire -fly of the sea. These animalcules occasionally occur in such large mucous masses as to interfere with ! UMAKEM the efficiency of fishermen by clinging to Fun, Magic and Mystery Airplane Workchest, containing aircraft work table with 56 Feats in Magic, 250 New Jokes, 21 Puzzles, 1 mitre cutting board and length gauge, steel drill, steel their nets. Fortune Telling Tablet, 52 Money- Making Secrets, hammer, Model Maker's steel square, screwdriver, sand- 15 Card Tricks, 71 Toasts, 58 Verses in Comic paper block. 10" scroll saw, together with finest quality But this luminescence is not due to any 41 Epitaphs, and 11 reed and bass wood, aluminum. silk, para rubber. full Poetry, 10 Funny Readings, set of blueprints. directions. and all fittings for building organic decomposition or exhalations of Parlor Pastimes. You get all the above- mentioned one 36" Blerlot Model flying Monoplane. Price $10.00. phosphorescent gases (the vapor of phos- and our big illustrated Catalog of 125 Magic Tricks Other UmakeM Outfits 50e to $50. phorous is for only 10 cents. Write today. W. R. PRICE, Inc. trioxide phosphorescent). It is No. 2 UmakeM Building, 127 Fifth Avenue, New York a sort of phosphorescence of the protozoa. MYSTIC MFG. CO., Contributed by JOHN MARCHETTI. 909 Springwella Ave., Detroit, Mich. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 927

1 111111I11IIIIIIIIIIIIiiiu

machinist says: BOOK REVIEW "Sure I'm using them, the THE GAS MOTOR, by Max Kushlan, same as most of the men in B.S. 366 pages, 86 illustrations, cloth are doing. Some of the bound, size 7/ x 5/ inches. Publisht the shop by the Branch Publishing Co., Chicago. Starrett Tools in my kit, I bought The fundamentals of the gas motor, -rather than mere structural details, are covered lucidly in this when I was an apprentice. excellent book, which should find favor among all interested in automobiles, motor boats, and wher- ever the gas engine may be applied. "Y'see, it's like this. We got the The author evidently has thoroughly surveyed when we were kids. We saw the his field, and selected for explanation the matters habit which in his opinion were of the greatest impor- older men, the ones that were doing tance in placing the subject fully and clearly before the student as well as the expert. the finer work, preferred Starrett Tools Among the many virtues possest by the book are the questions placed at the end of each chapter, re- because they knew they were accurate, viewing the subject matter immediately preceding it. This should prove a welcome feature. and we copied after 'em -just like our As a practical handbook the volume has few peers. Detailed instructions for the cure of ills kids are doing today. common to gas engines are given, as well as an appendix of useful constants and formulas. "How's that ? No, I wouldn't go so far as to say that Starrett Tools by themselves will THE MODERN MOTOR CAR, by Harold make a good machinist, but I'll say this P. Manly, 536 pages, 225 illustrations, - flexible leatherette bound. Publisht by Starrett Tools will make it a lot easier for Laird & Lee, Chicago. Size 5 x 7/ any machinist to do good work. inches. "The Modern Motor Car" is announced by the "Yes, I've got one of their `Starrett Data publishers as a book of simplified upkeep, giving Books for Machinists, and believe me, it the construction, care and adjustment of motor car units, together with shop and roadside methods saves a lot of time and mistakes. If I want of trouble location and repair. There are sections on how to buy, stake and use materials and sup- to know a decimal equivalent, a taper dimen- plies. Among other things, descriptions are given sion, the speed of a milling cutter, or something of the operation and repair of electric engine starters, lighting systems, magnetos and ignition about materials, I don't have to guess or ask parts, electric brakes, gear shifts, etc. Add to the above imposing list of attributes the fact that the - I just look in the book and find out. It book is intended for repairmen, owners, drivers, set me back seventy -five cents at the hard- salesmen and students, and it will be evident that the field has had quite a complete consideration. ware store, but it saved me a blame sight Not least interesting in the book is the section in week." on electricity, which explains in simple manner more than that the first the essential principles of the subject. As Mr. Manly says, "Without electricity, the modern gaso- line automobile would be an impossibility. Elec- tricity is used to fire the gas in the cylinders, to The L. S. STARRETT COMPANY start the engine, to light the lamps, and, in some THE WORLD'S GREATEST TOOLMAKERS cars, to shift the gears, operate the horn, furnish foot and hand warmers, cigar lighters and all Manufacturers of Hack Saws Unexcelled manner of necessities and conveniences." This section covers 130 pages and would alone ATHOL, MASS make the book a worth -while addition to anyone's technical book -shelf.

The utility and convenience of Star- LIVING ON $800 A YEAR. Paper rett Tools are second only to their accuracy. Catalog No. 21 "LE" cover, size 5/x734 inches, 16 pages. sent free on request. Publisht by the author, Leon Miller, Philadelphia, Pa., with an attractive cover showing his home. The title of this book brings fond memories of a current cartoon running in the daily papers un- der the heading of "How Do They Do It ?" Which is what we are wont to ask after reading YOU can BUILD this over the author's interesting answer to the high cost of living. With the certainty of conviction, he has outlined the program of events for the entire 52 weeks of the year-food, clothes, house expenses, rent, the doctor, the butcher, the baker PHONOGRAPH easily! and candle -stick maker. Do they have pleasure? You bet they do, and, by the way, we refer to the both halves of this TREMENDOUS SAVING IN COST marriage partnership; which is the "better -half" we don't profess to know. Probably they are still You -don't need to be a cabinet maker. We trying to settle that eternal problem. Let us not get too far away from the subject of the book, have mádeìit an easy and a pleasant jobwith, however. Among the principal schedules worked furnish blue orn out by the author and his spouse is the "menu." Simplified `°a erama, reatìv -built hom, cabinet We must eat, you know! Even if we live out -of- Our Plans pieces, motor, and all metal parts complete. You do the assembling. 6 models to choose from. A few doors like the Indians. Here we find a weekly hours' work, and you will have as fine a type of phonograph as any produced, time -table, figured down to the fraction of an and at a price away below what you would pay in a store. ounce as to what we shall have to -day, to- night, etc., etc. Looks good, but, we note that the "left- Keep the Savings in Your Pocket overs" of the noon meal of Sunday are disguised Machines play all records, will have a wonderful tonal quality, excelled by none. and used for the evening meal on Monday, and No need now for any family to be without a phonograph because of the cost. THE MAKAFONE solves the problem. BUILD IT YOURSELF AT LESS THAN so on and so on, which gives rise to a pertinent ONE -FOURTH REGULAR COST, but equal to the high priced cabinet machines. question in our minds as to how we originally Free Records with each outfit. SEND TODAY FOR FREE CATALOG and full started, or whether the steak used is elastic and particulars of our wonderful offer. Many a manufacturer got his start in this can be stretched to last indefinitely! From past way. Why not you? Build machines and sell to your friends. Ask us about this. experience we know that our better halves have AGENTS ATTENTION often served us a "variety" that frequently needed You can matte and sell this machine the help of a stone -crusher, but then she's a from our plans at a profit of $50 to ,w RITE TODAY! young, sweet person, and thru our love for her $T5 each. Others are selling two and M3DERN PHONOGRAPH SUPPLY CO. we'll get a regular meal some day, provided the three a week. Here is your opportunity f 143 Springer Bldg., 313 So. CIhigp Si. Chicago, ill "book" and "our stomachs" hold out long! to make big money and become Inde- , Cie ue,.ee: rie..e ,era me ma .euew.rs of roue that pendent. Pleasant and profitable work, obaa tian io me. Horrors upon horrors! We overlooked the fact START TODAY. 111 that the "Old Man" will give this the "once over," None MODERN PHONOGRAPH SUPPLY CO. and if he spies that 800 bucks per annum fairy- i' Streut Address tale, good -bye to our 100 per and the struggles of 143 Springer Bldg .31So.3 Catoa St.,Chicago,l. the Review Editor will cease miserably. Maybe City or Town - m.ar You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 928 ELECTRICAL EXPERIMENTER January, 1920

you would like to try out Mr. Miller's schedule he and his wife have lived the life, you know - but remember the male gets (2) suits a year, the- female gets a few odds and ends every year, whether she needs them or not; the coal? oh! a little; movies? yes; candy ? ? ?? smokes ? -That's inhuman and uncivilized! As for us-but seri- IID ously speaking, it can $800 be done on a year. TRADEI MARK But it requires an iron will, or rather two of them. Aoth SPLENDORS OF THE SKY, by Isabel Martin Lewis, A.M. Cloth bound, 343 pages, 20 illustrations, size 5x7 inches. Duffield and Company, New York. One feels satisfied and inspired after rising from a few hours spent with what is one of the most *41 refreshing books issued iduring the last few -- years. Isabel M. Lewis, the author of that splendid book -"The Splendors of the Sky" , needs no introduction to - r readers of the ELECTRICAL t11111111111111111 EXPERIMENTER, who have enjoyed her monthly astronomical articles. "Splendors of the Sky" is an ideal book for the seeker of astronomical information who does not wish to be encumbered with a treatise on A Fascinating Toy -and More! advanced mathematics which is generally added to astronomical texts, as the unrelished seasoning to a tasty subject. The Kidphone is a complete, serviceable, superior tele- Simplicity and clarity of exposition seems to be Mrs. Lewis' aim thruout. Discoveries of the phone, ready for immediate use -for fun or serious pur- last few years are explained in such a manner as to make them palatable to every reader; there pose, indoors or outdoors. Included in the set are two is a chapter on "Solar Explosions," sudden, but rather infrequent, appearances at the surface of transmitters, two receivers, battery, and telephone wire, the sun of hydrogen "bombs." full "These 'bombs'," says Mrs. Lewis, "are ap- as well as instructions. parently violent explosions of highly heated hy- drogen gas in regions of great solar activity. Boys and girls -and grown ups, too -will marvel at the At times, according to Dr. Ellerman, of the Mount Wilson Observatory, who discovered them, clear tones, and faithful voice reproduction of the Kid - they will follow one another like balls of a Roman candle at intervals of ten or twenty min- phone, yet the receiver weighs but % ounce. The idea utes. These "bombs" generally appear at the edge or at one side of active sun spot groups of operation is new to America. that are developing and are composed of many members. Repeated explosions often occur al- most exactly in the same place." LET THE KIDPHONE ENTERTAIN YOU THIS WINTER Another interesting recent discovery discust is the existence of a tiny body two or three hun- Price $10, at your electrical dealer, department store or from us direct dred per cent hotter than the sun, yet with a diameter only one -hundredth as great. Only two C or three hundred per cent hotter, in soothl Department Besides these new things, much care is given to the. regular astronomical topics. Each planet AMERICAN THERMOPHONE COMPANY has a chapter to itself and the other bodies of 1 1 4- 1 16 Bedford Street Boston, Mass. this vast universe are also given justice. But what is particularly attractive about the book is its arrangement. The chapters are not lengthy, and they are crowded full of facts more interesting than the most rampant fiction. A Motors, Electrical Toys and chapter every few nights will give anyone a prac- tical knowledge of astronomy as it is today, and Specialties Are Best a great deal of pleasure besides. Knapp Goods have stood the test for 29 years. No detail 1n, construction has been spared to make them the beat that money. can buy. The complete Knapp line includes Toy and Power V cri icran Lighthouse Motors, Gen- erators and KNAPP- "LEADER" Beams Dynamos. Spe- An efficient and reliable motor that greatly re- cialties and sembles the big motors of real power plants. (Continved frotta page 867) Novelties Drives from either pulley. Two speeds and reverse. that A motor that you will be proud .o own and ono muse and in- that will give you unlimited service. ,,truct. Fans, Rheostats, the atmosphere is clear enough so that a Compasses, etc. fairly bright light is discernible for sixty And Knapp prices are al- miles or over. In surveying in the moun- ways lowest. tain regions of this country, the Geologi- Always insist cal Survey have signaled positions to each on Knapp other over distances of about a hundred Goods. miles. with a small electric light operated from eight dry cells. KNAPP DYNAMO MOTOR OLD LIGHTHOUSE HAS RANGE OF ONLY 25 will electroplate, charge storage batteries. run lamps. motors, train of cars. induction colts. -in fact. the number MILES. of experiments it can be used for is unlimited. Runs on 4 to 6 Volts or can be connected to run on 110 Volta "The greatest range of any lighthouse in through a transformer. the world is only about 25 miles! The Price, Complete, $8.80 Price, Complete, $4.40 reason for this is very evident; the ocean is a curved surface. This curvature ap- Order to -day. Or your dealer can secure them for you. DESCRIPTIVE CIRCULAR and pears to have a remarkably short radius CATALOG of celebrated KNAPP MOTORS and Electrical Specialties from IOc up mailed FREE on request. when one observes how quickly lighthouses disappear over the horizon viewed from KNAPP ELECTRIC & NOVELTY CO., 523 West 51st Street, New York City the deck of a departing ship. The limita- tion is, therefore, geographical; it is the curvature of the earth which defines the range of a lighthouse. The only method AHR ANE SUPPLIES of increasing the range is to locate the MODEL light as high above sea level as pos- I: aafllld e. sible. The highest light in the United end ffll Modell Aïlrpliene States is that at Cape Mendocino, Cali- fornia. This is four hundred and twenty - Send 5Q f o r catalog nocked -down scale of new machines, ports, s,ond seppliees_ two feet above sea level, and has a range models of about twenty -five miles. The Navesink Weld ;sag River Mfg. C co. 6á2 rosdllwt&y, t rookilyn, 1 70 110 Light is two hundred and forty -six feet high and has a range of about eighteen miles. In figuring the distance of the hori- READ THE CLASSIFIED ADVERTISEMENTS zon from various heights above sea level, ON PAGES 963 -964 and 966 there is a simple formula which every sea- faring man knows. The square root of

you benefit by mentioning the "Electrical Experimenter" when writino to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 929 the elevation above sea level in feet is ap- proximately the distance of the horizon in miles. Man Who "With the increasing speed of modern The Wouldft vessels, there is a demand for lighthouses of greater range. It is somewhat surpris- ing to realize that the old Pharos of Alex- Stay Down andria had a range probably just as great as our best lighthouse of today. All of the remarkable improvements have been re- finements only. The fundamental requisite of lighthouses, that is, range, has remained the same thru the past two thousand years! THE VERTICAL SEARCHLIGHT FOR LIGHT- HOUSES. "During the war there was developed a completely new branch of illuminating en- gineering; this is the anti -aircraft search- light service. This service gave us a great deal of new data and experience in pro- jecting powerful lights upward into the sky. During the latter part of the war and since the war, searchlights have played the part of lighthouses for aviation and have been found to be serviceable over ranges He was putting in long hours at monotonous unskilled work. His small which are unheard of in marine lighthouse pay scarcely lasted from one week to the next. Pleasures were few and far practise. Aviators have picked up the beam between and he .couldn't save a cent. from a single searchlight at distances of over a hundred miles and have been guided He was down -but he wouldn't stay there! He saw other men promoted, by it from this distance up to the search- what they could do he could do. Then he light beacon. and he made up his mind that "The trans -Atlantic flight has now been found the reason they were promoted was because they had special training accomplished by both airplane and diri- -an expert knowledge of some one line. So he made up his mind that he gible. It is only a matter of a few years would get that kind of training. before ocean flights will become regular enough to demand beacons. It will be re- He marked and mailed to Scranton a coupon like the one below. That membered that the NC-4 made its flight was his first step upward. It brought him just the information he was look- with the aid -of the searchlights from the ing for. He found he could get the training he needed right at home in the destroyers along the line of flight. hours after supper. From that time on he spent part of his spare time studying. WHAT MAKES THE SKY BLUE? first reward was not long in coming increase in salary. Then "A powerful light projected vertically in The -an the form of a narrow beam will illuminate came another. Then he was made Foreman. Now he is Superintendent the column of air thru which it passes, with an income that means independence and all the comforts and making this visible as tho it were a pillar pleasures that make life worth living. -, SA PI OUT Nang of light. This visible beam is caused by INTERNATIONAL CORRESPONDENCE SCHOOLS the scattering of the light rays by the myr- It just shows what a man with ambition can do. And this man is only one out of Box 6213, SCRANTON, PA. iads of dust particles which fill the air. It IExplain without obligating me, how I can quality for is astonishing to learn that the average hundreds of thousands who have climbed the position, or in the subject, before which I mark X. on clear days, contains about the same steps to success with the help of ELECTRICAL ENGINEER CHEMICAL ENGINEER atmosphere, Schools. Electrician SALESMANSHIP twenty thousand dust particles per cubic the International Correspondence Electric Wiring ADVERTISING MAN Electric Lighting Show Card Writer centimeter, whereas the air around New Electric C. Running Sign inter high 200,000 What about you ? Heavy Electric Traction RAILROADER York City averages as as dust Electrical Draftsman ILLUSTRATOR particles per cubic centimeter ! Most of Are you satisfied merely to hang on Eleetrle Redline Designer DESIGNER are or would you, too, like to Telegraph Expert BUSINESS MANAGEMENT these particles are too minute to be visible, where you Practical Telephony Private Secretary even under a powerful microscope, but they have a real job and real money ? It's en- MECHANICAL ENGINEER BOOKKEEPER to Mechanical Draftsman Stenographer and Train have, however, the property of scattering tirely up to you. You don't have stay Toolmaker Cert. Pub. Accountant down. You can climb to the position you 1 Ship Draftsman Traffic Management light. It is this same phenomenon which Machine Shop Practice Commercial Law gives us our blue sky. The sun's rays, in want in the work you like best. Yes, you Gas Engineer GOOD ENGLISH CIVIL Common Subjects can ! . The I. C. S. are ready and anxious ENGINEER Sabool passing thru the hundred miles of our at- Surveying and Mapping CIVIL SERVICE mosphere, are scattered in all directions by to come to you, wherever you are, with MINE POKER'S ORENG'It Railway Mail Clerk ARCHITECT STATIONARY ENGINEER these particles and we thus receive light the very help you need. Arehiteetaral Draftsman Textile Overseer or Supt. PLUMBING AND HEATING AGRICULTURE g Spanish from all parts of the sky. Surely when you have an opportunity Sheet Metal Worker Poultryiallog ® Frauds "This sky light, however, is noticeably that means so much, you can't afford to Navigator Automobile. 'who. blue in color, whereas the sunlight is a let another priceless hour pass without at yellowish white. The blueness of the sky least finding out about it. And the way Name is caused by the fact that these minute par- to do that is easy- without cost, without Present ticles in the atmosphere scatter a larger obligating yourself in any way, mark and Occupation percentage of the short blue and violet rays mail this coupon. Street than they do of the longer red and yellow and No rays. City State WHY THE VERTICAL BEACON? WHEN YOU GRADUATE "The new Sperry high intensity electric From the College of Electrical Engineering arc is ideally suited for such vertical bea- of the School of Engineering of Milwaukee with a B.S. Degree, you are thoroughly and practically trained for immediate positions of importance. cons. The requisites of a small slender Three years of intensive theoretical and practical application to purely beam of maximum intensity, having a technical electrical studies, will give you a foundation upon which you can build a successful future. bluish hue, are all met by the concentrated ADVANCED METHODS AND SPECIAL FACILITIES beam cast by this arc. Every one who has combine to produce educated electrical men -a credit to their in sky profession. seen these bluish beams playing the 60 EXPERT SPECIALISTS at night can appreciate the value that this in their particular lines personally guide you in the laboratory, draft- ing room and lecture room work of this school. Meet them at projector will have as a beacon. The blue "America's Most Practical Electrical Institute." color of the high intensity arc has a double WINTER TERM NOW OPEN this service. First, a greater 'Tarn While You Learn" system. Provision for securing deficient advantage.for High School credits. percentage of the rays are scattered by the Clip the coupon NOW for full in- dust particles in this bluish beam than is formation and latest bulletins FREE! SCHOOL OF ENGINEERING OF MILWAUKEE. possible with any other source of light. 151.373 Broadway, Milwaukee, Wis. This causes the beam to be distinctly vis- -CLIP HERE------ible. The other advantage is that the School of Engineering of Milwaukee. 151 -373 Broadway, Milwaukee, Wis. Engineering human eye is more sensitive to the blue I Gentlemen :-I am interested in your 3 -year Electrical light than to any other color when the in- course with B.S. Degree. Kindly send full information and latest tensities are very low. Hence, at great bulletins. distances from the beacon a faint bluish I Name color may be distinguished more easily than Address any other hue. Therefore, the high inten- I Age Education

t. 930 ELECTRICAL EXPERIMENTER January, 1920

sity arc has the advantage at each end. It produces the most visible beam at the send- ing end and makes the most easily discern- 4 FAMOUS BOOKS! ible beam from the distant receiving end. "In lighthouse work the varying condi- tions of the weather are all important. The light that is visible thru the greatest variety of atmospheric conditions is most desir- able. We have clear weather, cloudy EACH ONE weather, hazy and foggy weather, with which to deal. A BIG EFFECT OF CLEAR WEATHER. "On a perfectly clear, cloudless night the SUCCESS! vertical beacon is somewhat faint, due to the decreased number of dust particles, but it reaches to great heights and is visible from great distances because of the clear- ness of the atmosphere between the beam and the observer. "As the weather becomes a little more misty or hazy a remarkable advantage of this system is evident. The increase in particles in the beam increases its intensity and makes it more visible almost in the THE same proportion that the haziness decreases visibility. The pillar of light is automatic, BOOKS the lower the visibility the brighter the pillar. We therefore take advantage of YOU the very thing which tends to decrease the range and maintain the range with it. MUST THE VERTICAL BEACON IN FOGGY WEATHER. HAVE "When we consider fog, thesproblem dif- fers. Fog consists of smallswaterdrop- lets over a thousand times as large as the ever -present dust particles. When *fog is heavy no light will penetrate it to any great distance, and one scheme is as futile as another. But a sea fog is not always deep ; many of the fogs are low -lying blankets of mist, and it is not unusual to see the stars above on nights when light- houses are almost useless. Under such conditions the vertical beacon has the ad- Wireless Course in 20 Experimental Electricity No. 1. How to Make Wire- vantage of being visible by showing its Lessons Course in 20 Lessons less Sending Apparatus pillar above the fog where the navigators By S. Gernsback, A. Lescarboura and By S. Gernsback and H. W. Secor. E. E. No. 2. How to Make Wire- may discern it. H. W. Secor, E. E. A Course of the theory and prac- less Receiving Apparatus "Lastly, Expert - the very usual condition of A course that tells you everything tice of Electricity for the By 20 Radio Experts you possibly menters. Undoubtedly one of the cloudy weather is perhaps most can want to know about Two Remarkable Books the ad- "Wireless" starting off in lesson No. most complete and comprehensive vantageous condition of all for demon- 1 by explaining the Principles of treatises of this special subject ever Book No. 1 contains 100 pages, Electricity. The second and third published. Written by the same size 7 x 5 in. and 88 illustrations. strating the efficacy of the vertical beam. lessons are devoted to magnetism, authors as the famous "Wireless Book No. 2 contains 100 pages. motors, generators and wiring. The Course in 20 Lessons." size 7 x 5 in. and 90 illustrations. "Night clouds vary in height from half mysteries of 'Wireless" are unfolded Every phase of experimental elec- Both paper bound. a mile to seven miles. The vertical beam to you by the use of such simple lan- tricity is treated comprehensively These two books have been written guage so skillfully used that of ne- in plain English. A book not only and published entirely for the wire- produces on any cloud within ten miles cessity you must understand every word. for the beginner but for every ex- less enthusiast who wants to make above it The subject is not treated superficially, perimenter and student of Electricity. his own radio apparata. Only strict- a patch of light that is surprisingly however, for there is a whole lesson de- New Experiments are described and ly modern radio apparata are de- brilliant and is visible from great distances. voted to the Theory and Mathematics of explained and nearly every appli- scribed and the illustrations and this epoch marking subject. The last cation of Electricity in modern life descriptions are so clear and simple If the clouds were low -lying and not more lesson (No. 20) is devoted to a history is given. that no trouble will be experienced than half a mile in height the brilliant of Wireless. The book contains 128 pages and in making the instruments. fifty Size of book Is 7 x 101/4 In. 160 more than 400 Illustrations. Book No. I -How to Make Wireless patch would be visible approximately pages. 350 Illustrations, 30 tables. Flexible cloth cover...per copy 75o Sending Apparatus 25c miles away. When the clouds are high Flexible cloth cover per copy 75e Stiff cloth cover per copy $1.25 Book No. 2 -How to Make Wireless Stiff cloth cover per copy $1.25 Receiving Apparatus 25o and dense, one hundred miles' range of Postpaid Postpaid Postpaid visibility of the spot has been obtained. EACH VERTICAL BEACON HAS OWN SIGNAL. "The problem of making various beacons distinctive is much simpler than in present JUST OFF lighthouse practise, since any combination DESIGN-CONSTRUCTION of dots and dashes may be mechanically AUDION AMPLIFYING TRANSFORMERS signaled continually by means of a light RADIO MVO AUDIO FREQUENCY TYPE THE PRESS shutter. r. Joxcs "The use of a shutter is impossible in Design and Construction of present lighthouses, since only one portion Audion Amplifying Transformers of the azimuth is illuminated at one time, Radio and Audio Frequency Type therefore the optical system has to rotate and the flashes are produced by the rota- This latest and important book by Mr. Edward T. Jones, tion of the beams in azimuth. The vertical late Associate Editor of Radio News, will be of great in- beacon is visible in all azimuths at all times, terest to all radio amateurs thruout the land. The trans- formers shown in these books have never been described in a very great advantage. print before, and have usually been considered a manufac- turer's secret. Anyone who has several vacuum tubes cannot "We have spoken mainly of the applica- afford to do without this book bemuse it will enable him to build the necessary amplifying transformers very readily. tion of the beacons to sea navigation. It The designs are very simple and rugged, and anybody can is almost unnecessary to enlarge upon their make them without much trouble whatsoever. advantages for air travel. Inland as well Mr. Jones, the author, is a practical man who is an ex- perimenter himself and knows whereof he speaks. The book as shore beacons will be required for this is printed on good paper and has an attractive cover in two field to make night flying possible. Inland colora. Paper bound. Size 5 in. x 7 in. Contains many illustrations, diagrams and working data necessary to build guide -posts of light will probably be in- the transformers. stituted for airplanes even before the pres- VoBLISses BY THE EXPERIMENTER POBLISM(NG, CO. INC. ent shore lighthouses are supplemented Z33 POLTON ST. NEW YORK CITY with similar apparatus for the mariners. PRICE, Postpaid, 25c But the ultimate adoption of this system is more than a possibility ; it is the next logi- THE EXPERIMENTER PUBL. CO., Book Dept., 233 Fulton St., New York cal step in this period of rapid and revolu- tionary progress."

you benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 931

Electric Locos Cross Moun2ains (Continued from page 874)

turns electrical energy to sub -stations to be utilized by other trains -from 25 to 52 per cent of power is recovered by regenera- tive braking! MORE EFFICIENT OPERATION The electric locomotive can be operated for a thousand miles or more with only casual inspection, whereas the steam loco- motive on mountain work requires con- siderable attention at every division point. This has made it possible to operate the J electric locomotive over several old steam divisions, and practically eliminates round- houses and yards at intermediate points. ICHOO W,E DGE 11S POWER By contrasting its workings with the A specialized in steam locomotive in cold weather, as this electrical training, gained hand hand railroad points out, the superiority of the with practical experience in actual laboratory work will electric locomotive is notably demonstrated. assure for you a In cold weather a steam locomotive, losing position of importance and responsibil- much of its power thru heat radiation, ity in the field of mighty opportunity -electricity! draws lighter loads, makes less speed, and has greater difficulty in climbing grades Let The New Year Find You Started and penetrating snow-drifts ;-while the electric locomotive, aided by the cold in with the work of your choice in the large and splendidly equipped keeping its motors cool, is able to draw laboratories, shops, drafting rooms and class rooms of the School maximum loads, maintain its regular speed, of Engineering of Milwaukee. and, by its immense power, to drive thru snow- drifts with comparative ease. Become A Master Electrician in One Year! The practical methods of instruction and large faculty of special- ized experts of the School of Practical Electricity will prepare AboRishiIIìg Omu ®Ille you in one year for highly paid positions. Countless graduates Ellectrficeally testify by their success to the actual value of the course. (Continued from page 880) School of Electrical and Mechanical Drafting A one year course that will train you to become a first class drafts- ing fine powders as in the manufacture man of lamp black, zinc oxid, desiccated food, and designer. A most practical course leading to highly etc. paid and attractive positions. The process is generally applicable to collecting suspended solids and liquids car- Institute of Electrotechnics ried in a gas. It has not yet been devel- Junior and Senior units -1/ years each -prepares for rapidly growing oped to the point where it can be used to new field of electrical specialization. Graduates also eligible for im- 0 separate gases of different constituency. mediate entrance to College of Electrical Engineering with B.S. Degree One of the interesting features of this in 3 years. process is that, tho originally designed simply to suppress a nuisance, it has in "Earn While You Learn" practise almost invariably proved a highly / Iam profitable investment, of the if you so desire. All of the various courses at the School inter- because value of Engineering allow / ested r n of the otherwise wasted material it re- students part time employment / t h e below covers. either half days or alternate weeks. Thus practical / m a r k e d experience as well as ample remuneration can be / courses. Please obtained. I send catalog and RECLAIMING f u 1 1 particulars COPPER FROM FLUE FREE. GASES, AT A PROFIT. Extension Department -Electricity, Mathematics / and Drafting, Students "Frat House" -Room School of Practical For example, a copper smelting company and board $28.00 to $32.50 per month. 1 Electricity. one Year installed an electrical precipitation equip- R.O.T.C. All athletics. / o ment at the cost $113,900. The / School of Mechanical and of operat- Electrical Drafting. One Year ing expenses (power, labor, supplies, etc.) CoInstituteCourse. were $14,600. But the value of the copper Spring Term Opens April 1st. .. of Electrotechnics. Write today for latest bui- .Extension Department. dust collected (at 12 cents a pound) was / Six Months Trade $180,018 a year. Thus, this installation letins and full particulars. e Courses. paid for itself before the year was up and / Name thereafter operated at a magnificent profit. School of Engineering / Again, a cement plant has an equipment, of Milwaukee which cost $180,000 to install and $10,395 Address a year in operating expenses. Tho the 152 -373 Broadway / material recovered is worth much less than Milwaukee, Wis. / Education Age copper dust, its value per annum at pre- / war prices was $74,325, of which about one -third is cement dust at $1.00 a ton and two- thirds is potash at 70 cents a unit. This also represents a highly satisfactory profit. These examples are of large plants. We have been fortunate in securing thru auc- However, small plants may be installed at tion several tons of guaranteed pure double an- CORE WIRE nealed Norway Iron Core Wire and are selling approximately proportional cost with prac- At Pre -war Prices, 20cts. lb. this wire to "Experimenter" readers at 20c lb. tically proportional recoveries, since the This wire is just the thing for spark coils, transformers, etc., and it is, of course, a very much efficiency is not dependent upon the size of more superior product than the usual iron wire. We have only one size left: the plant, but more particularly upon the 24 INCHES LONG. Thickness about No. 21 B and S If this size should be too long we advise cutting the wire down yourself by means of shears. operation of it. As long as the supply lasts we offer this wire as described above to our customers at the very low price of The ability of this process to obtain pot- 20e a pound. Add postage or we will ship express collect. Order at once. ash in commercial quantities out of the ELECTRO IMPORTING CO., 231 Fulton Street, New York City vapors from cement kilns was a genuine You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 932 ELECTRICAL EXPERIMENTER January, 1920

surprise to the world and' will undoubtedly have economic consequence of the great- YOUR est importance. AMPLIFY RADIO SIGNALS PRINCIPLES OF ELECTRICAL PRECIPITA- With the new DETECTAGRAPH -TRANS- the amplifying process is attained is by attach - TION. MITTER, the amateur can amplify radio sig- ing with tape the DETECTAGRAPH-TRANS- A treater for electrical precipitation is nals to such an intensity that he can hear the MITTER to the regular wireless receiver. signals about his station without the need of Not only is this instrument applicable for a comparatively simple structure. The ac- the telephone head set. amplifying radio signals, but it can be used companying schematic diagram illustrates By the addition of a loud talking telephone with equal satisfaction for magnifying other a typical pipe treater. In general it con- he is able to hear the messages many feet sounds. Phonograph music can b transmitted away from the instrument. from one place to another by means of this in- sists of two large horizontal flues con- The super - sensitive DETECTAGRAPH3- strument, and those who are afflicted with deaf - nected together by a number of small ver- TRANSMITTER herewith Shown is two and ness will find enormous benefit by using this tical pipes. Gases enter thru one flue, pass three-eighths inches in diameter, five- eighths of transmitter. It is the greatest device for build - an inch thick and weighs ing your own loud talking thru the vertical pipes and are discharged less than three ounces. It SO R -.SENS/T /vE telephone, detectagraph thru the other flue to a stack, exhaust fan, is the most sensitive / and other devices. Can or other draft producer. The gas is then sound detecting device be used for any purpose exhausted into the atmosphere. Some ever brought before the , 0 where a sensitive detect - public. I ing instrument is re- treaters are operated with an up- draft, The manner in which M/CROPHONE G s quired. some with a down- draft, according to the particular local conditions to be met. Some treaters employ rectangular passages in- stead of pipes to connect the two flues. These are generally referred to as plate or box type treaters. The principles of ., operation. for all these types of treaters is the same. The actual precipitation of the dust or fume occurs in the vertical pipes referred to above. Carefully centered in each, is Detectagraph Rheostat, suspended a small wire or a small chain. especially made for am- Our Super -Sensitive De. Our Special No. 25 Loud plitying circuits. Price, These constitute the negative electrode of tectagraph Transmitter. Talking Receiver. Price, $2.00 Complete the treater system. The inside surface of Price, 31.00 Complete $4.50 Complete Super- Sensits eto No.be the pipes constitute the positive electrode. used In connection wl th Detectagraph- Each wire or chain is carefully insulated .: - -.:.. A d l u sted Transmitters $10.50 Model AdjudAdjusted M o from its pipe and from the ground, and Horn. with 0e,, Horn, with is charged to a high potential, usually at No. 20 High Grade lf Grade Loud No. 20 High s. from 25,000 to 65,000 volts direct current. Talking R e - Loud Talking Wall ceiver, Cord Receiver. Cord , ' The tubes themselves are grounded. Thus, `#% Plugs and Plugs and Wall s l i. within each pipe is created an intense elec- Desk Stand Base, Price. $12.00 B a s e. Price, Complete `r trostatic field. The gases passing thru this - The Detectagraph $12.00 Cam field' become ionized, and the ions travel Junior Deaf -Phone pieta $18.00 Detectagraph $18.00 with high velocity in a direction at right Equal to any $35 in- Order direct act This detecting instru- angles to the electrodes causing the field. strument made. Out- from went of marvelous lit consists of Super- Or write for free descriptive circular. sensitivity can be These highly charged ions are continually Sensitive Transmitter used for detecting colliding with the suspended solid and with cord connector; secret conversations. Super - Sensitive Ear BOISSONNAULT outfit consists of liquid particles in the gas, and the ions Pie c e with small G. COMPANY Sensitive Transmit- black cord; Black ter, 25 -ft. B l a c k impart a charge of like potential to such Single Headband; 26 CORTLANDT STREET NEW YORK CITY Cord, Receiver, particles, which in turn begin to travel to- Black Case and Two Makers of Super- Sensitive Microphone Devices Headband, Case and Batteries. Battery. ward the electrode of opposite polarity. .. Since the negative suspended electrode is of much smaller area than the electrode formed by the inside surface of the pipe, a r , there is much greater electrostatic stresses _ 4ptl> SPECIAL $1.00 per unit of area in the neighborhood of the wire, and as a result far greater ionization ONLY about the wire. Thus the gas receives a SALE! x static charge of the same polarity as the wire, and the solid or liquid particles in We have on Postage the gas receive charges of this same polar- hand 2,000 extra. ity, which causes them to be projected t against the inner surface of the pipes, Carbon -1y S'-lip. Weight, to stick Grain Trans- = 2.bs. where they tend and accumulate millers as ä_° until the electric power is turned off ; after Diameter, is per photo- Reduced Photograph of Trans- which the accumulation of dust usually 3 % ins. from the pipes by loosening it graph. They - mitter showing nickel plated case collected and Hard Rubber Mouthpiece the pipes, and col- are first - by rapping the sides of class instruments and may be used for all kind of experiments, especially for lecting the 'dust in hoppers at the bottom. wireless telephone sets, where a heavy current is to be passed through. Slightly The treater tubes are usually arranged used, but in perfect working order. Money refunded if not satisfied. A real in a series of units. Each unit or section bargain. e, Order one or more today. is independent of the rest and is supplied -, 231 YORK with dampers and electrical disconnecting THE ELECTRO IMPORTING CO Fulton St., NEW switches, so that it can be shut down for cleaning or repairs, without interfering with the operation of the other sections. To produce the high static charge on the suspended electrodes a ijsni- directional cur- Tlje 1reakerE; rent of high voltage is used. While it is possible to generate direct current of a po- tential in the neighborhood of 100,000 ,volts, Atlantic City's Newest it is at present better practise, to obtain. this' uni- directional high voltage current by Yec- Fire -Proof Hotel tifying a high Voltage alternating current. Ocean Front. Unusually attractive Alternating current at low voltage is stept- during the Autumn and Winter sea- up to the desired high voltage by means of a transformer and then changed into uni- sons. directional current by means of a mechani- cally driven rectifier. Accordingly, the American and European Plans usual equipment for electrical precipitation involves the following: -A source of low Luxurious lobbies, spacious verandas and sun parlors overlooking the ocean. voltage alternating current; a step -up evening concerts. A palatial residence Charming afternoon musicales and transformer ; a high voltage rectifier ; for those seeking rest and recreation. Sea water baths. Fireproof garage. means for driving the rectifier, also a Illustrated booklet sent on request. switchboard and accessories. Photos cour- tesy Westinghouse Electric & Mfg. Co.

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 933

Finish This Science IIlm Slangs Story For By EMERSON EASTERLING Yourself (Continued from page 913) The girl got $6 a week and was lonely. "Piggy"- you can imagine his or aunty's knitting thread or pop's fishing kind -was some guy waiting down - pole. Next we hear of wise stairs. Heknew The Electric Safety razor makes shaving a springing on the g.p. the tantalum. But where pleasure. Blade vibrating 7,200 times a minute not until we had the carbon type improved cham- cuts the beard smoothly and without slightest seeing that the tan - pall or irritation -feels like a gentle massage. by metalization. Next, pagne Can be used with or without electric current. talum (filament was not the very best thing and mil- for Ford headlights, as it broke by looking s i c could mums.' lb. Lek -Tro Shay speak well of it at it too hard-and we all couldn't hold be had. But A barber says -"Have shaved for years and have that night never used any shaving device near its equal." our mouth right when in its presence all the she didn't A home user says- "The most pleasing shave I've time-so the high priced metal that we ex- go. over had in my life. Shaves my face closer than I That used to shave, but there is no after irritation or ill tract from shelite was stuck into the vacu- was Lord effects as I usually get from another razor.' ated glass shell-the famous tungsten. You Kitchener a No. 1 Made for use from Light Socket. could use the old hammer on it and still doing. Brit No. 2 Made for use from Dry Battery. anot her Write for illustrated circular describing Lek-Tro- not have to bring out the oil lamp. night? Shay Safety Razor fully. "Next some enterprising gink finds out VIBRATING ELECTRIC RAZOR CO. that nitrogen gas works better than the Dept. 122, Omaha, Nebr. absence of everything in the globe, and we tttts_t get the nitrogen gas lights. By coiling the wires and thereby concentrating the light O. Henry unit in the nitrogen environment, we get a glim that you can't look at and see (12 Volumes whether she had green or just pale blue stockings until you give your headlights tells about it time to recuperate from the shock -of the in this story, with that full light. knowledge of "That Nernst light we hear about is just women, with that oxide of Mother Earth in a few of her frank facing of sez, and that forms and when said earth is heated to the clean mind that right temperature it becomes conductive has endeared THE OLIVER OIL -GAS BURNER and the juice makes it glow, like the other him to the men makes any cooking or heating stove and women of a gas stove. Burns coal oil (kero- kind. It is a queer thing, the stuff is non- sene). No coal or wood. Cooks the land. and bakes better. Cheaper. Keeps conductor when cool. Glass is the same your home warmer. You regulate way, only not so much so. flame. FITS ANI STOVE ANYWHERE. No Great story fires to start, no ashes, no chop- big idea in the arc lights is : ping, shoveling, poking and drag- "The this the Writer ging of coal. Saves hours of work current passing from one pole of carbon and loads of dirt. Simple. Safe. Easily to the other particle seizes the stuff and From the few stove. Lasts lifetime.a Thousands passes it from one pole to the other. The who snapped Money -Back Guarantee. Free literatura up the first edi- AGENTS WANTED current causes the carbon to become incan- tion at $125 a OL;YER OIL -CAS BURNER & MACHINE CO.. descent by way of the resistance given to set before it was 1335 N. 7th St., St. Louie, Mo. to Wasters Orders Shipped From Frisco. the current. Some of the carbon is con- off the press, sumed in flame and the rest is deposited on the 120,000 who Oliver have eagerly The Oil-CasBurner makes the negative pole. In alternating current sought the beau- 2 gals. oil equal 971bs.coal the carbon is going each way, inter- tiful volumes of- fered you here mittently. from the profes-- among his AC F I EL METAPAD "In the incandescent -so called-type the sional man who sits DS wire is heated by the juice that passes books to the man on the street and IT SUPPORTS E.7-4 BINDS to the woman in every walk of thru it, by way of the resistance in the life-the whole nation bows to O. THE FRONT ARCH wire, to an incandescent state. We have Henry -and hails him with rove Instantly Relieves Metatarsal Arch Affections light. and pride as our greatest writer of Morton Toe, cramping of toes, en- stories. larged little toe joints, sole cal- "Is that plain ?" louses and spreading of foot. To Those Who Are Quick Worn In any Shoe, under "Plain as broad day light," Punk 're- or over stocking. Any turned. other foot troubles? JACK LONDON Write for f u l l "You see, in some cases, electricity flow- particulars. ing thru a conductor sets up resulting sur- 5 Vols. Given Away C.R.ACFIELD rounding vibrations, sometimes in the form Never was there an offer like Fool Specialties Marbridge Building, Dept. MA 1328 B'way (at 35th SI.) N.Y. of light, sometimes in the form of magnet- this. Not only do you get ism, sometimes both. The energy that is your 274 O. Henry stories in 12 volumes at less than others paid impeded in the electrical form is converted for one volume of the first edition, Want More Money into heat, a form of potential energy, or but you get Jack London's Works, something else -the converting of the 5 handsome volumes- without pay- HERE IT IS ing a cent. You get 17 volumes, forces is what really impedes the current. packed with love and laughter -a Hundreds of Men -elderly, young or It is the cause, not the result." big shelf full of handsome books. middle aged, make BIG MONEY "But lissen," spoke up Punk with a SHIPPED ON APPROVAL every month representing our maga- We will ship the two complete Bets so that you can dreaming, far away look in his left upper- look them over in your home and then decide whether zines. Work Your Way Through most eye, "why has no one thot to take or not you wish to buy. If you are not delighted with College, buy the hobbies you are in- O. Henry and the free Jack London notify us and out a patent on a light -bulb with the vac- we will take the sets back as cheerfully as we sent terested in ; or go into a good paying uum on the outside!" them. How could any proposition be more fair? business for yourself. You can spend all of your time or a few hours a money INSPECTION COUPON day. You can make spending LONG DISTANCE RECORD IN or you can guarantee yourself a BIG THE RIVERSIDE PUBLISHING INCOME. RADIO TRANSMISSION. 1 0 So. Dearborn St., Chicago, III. Please ship me on approval the Works of O. Henry, 12 If you can use more money and By keeping in touch with Los Angeles volumes, New Fabrikoid binding, gold tope. Also the 5 volume set of Jack London bound in silk cloth. If you are willing to put in a few hours and San Francisco virtually during the en- I keep the books I will pay you $1.00 as first payment a day, don't fail to investigate this tire voyage from Japan- sending mesages within 10 days after books are received and $2.00 per month until your special price of $29.00 for the O. offer. You will like the work and a distance of 4,855 miles -Frank Cummings Henry set only is paid, and it is agreed I am to re- no matter what your present pur- tain the Jack London set without charge. If not and C. H. Bowers, radio operators of the satisfactory I will notify you within 10 days and return suits, your faculties will be better Pacific Mail steamship "Columbia," claim both sets to you as soon as you give nie shipping in- developed. Write to -day for full they have established a world's record for structions as offered readers of Electrical Experimenter. particulars. long distance transmission of messages. Name THE EXPERIMENTER PUB. CO. They used a high -powered wireless outfit. Address Circulation Dept.,233 Fulton Street, New York Presumably they mean "ship to shore" Business or Employer transmission. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 934 ELECTRICAL EXPERIMENTER January, 1920 Whmt Atomic Forces C ®angd D ®o Physical Perfection Mental Alertness C-ontiuued from page 872) can be gained by a proper system of exercise. You will not only feel above pound of coal burned in the locomotive de- par physically, but will also have that velops 13,500 British Thermal Units. Each pound of coal thus yields 3,402,000 gram sense of mental alertness which is calories and for 60 tons of coal, we arrive possessed only by those in the best at a total gram calorie output of 408,240,- physical condition. 000,000. Divide this by the number of gram This picture shows the physical de- calories or 2,900,000,000 produced by one gram of radium disintegrating, we find that velopment acquired by one of our approximately five ounces of radium would pupils. His mental development is be required instead of 60 tons, or 120,000 even more interesting. What he has pounds of coal. This considers, of course, accomplished is within the reach of that we could disintegrate the radium dur- every boy, ing the trip between the two cities, so as normal man and through to release all of the caloric energy in the the Milo system of progressive exer- five ounces of the stuff (based on 2,500 - cises. year decay period). The difference in If you are going to exercise at all, weight between the coal required and the radium is almost inconceivable, so why not go after results ? You can startling is the ratio between the two. Radium, of accomplish more in three months by course, is very expensive at present, and our system than you can in three years this amount of radium would cost a pro- by any other system. During the digious amount of money, but presently we years we have devel- will undoubtedly see the cost of radium past seventeen drop to a figure several thousand per cent oped thousands of men and boys, and below what it now is. have turned out more physical marvels And this is not all, for we have merely than all other systems combined. used radium in this case to base our com- If you are interested in better health putation on for the sake of convenience. When our scientific investigators have at and physical and mental develop- last solved the method for us whereby to ment, send for our illustrated catalog unlock this marvelous store of energy in and folder No. 18, describing our the atoms of any substance, then we can system of training. We will show you use an ounce of any material and not par- ticularly radium, for as many of the world's the proofs of what our system will best -known thinkers in this philosophical accomplish. field have declared many times, one ounce of a certain metal, in this respect, is the Dept. 2. same as any other substance; but the great THE MILO BAR BELL CO., Third and Diamond Sts., Philadelphia, Pa. secret, so far unsolved, is -how to over- come and control the overwhelming force with which these electrons are held in their orbits about their central nuclei. A very small amount of coal and also a lesser amount of radium would be required to drive a railroad train from New York to Chicago, or vice versa, providing some NEW MOTORS genius will show us how to use coal, for ex- FACTORY GUARANTEED - ALL SIZES - IN ORIGINAL BOXES ample, to produce power in a steam locomo- tive wasting about 93 per cent of To Buy New Guaranteed Electrical without Your Opportunity Apparatus of Standard Manufacture. it in heating and other losses. It is a well - known fact that the efficiency of the aver- Single Phase Motors Charging Generators Polyphase Motors 7 Battery Charging Outfits age steam locomotive is about per cent. liasto volts, A. C.. 60 cycle, Suitable for all lighting R and 3 phase.e. A.C.. 440v, To operate on A. C.. 60 cycle. single phew 2600 R. I'. M. with paltry Battery Charging hoc 1750 RPM.. complete This lowly figure of 7 per cent then means and Power Requirement.. voltage as specified. . rd ta, d - with base and pulley. that that is all of the energy put to actual NP rolts, A. C., 1N waa te s/na. @ t rent, 11 asp. III 4 0.00 1/4 u1 R $24.502450 $16.50 wilhoul swilchbar/ N`-t on the while out of 100 cent h H. P. $42.50 work trip, per

Na. n - 15 rolls, 11 amp. III volts, A.C.,151'ana, 61 sons. of the energy in the coal, when we place it rPasa' mn .n1.t., $21.00 $68.50 2 m 38.50 with switchboard sP tJ I H. P. $59.50 in the tender car of the engine, 93 per cent 44 le,, O amp. $24.50 111 -221 volta, A. C., 251 watts, $75.00 is thrown Suppose that to- morrow 2 $46.50 24 rolls, without switchboard away. Ili.. 214 amp. $24.50 2H. P. $72.50 an engineer produced a steam locomotive N: P., 111.211 cells, r. ut- $67.550 221 rolls, A.C.,311 walla. it roll., $85.00 uoa. with .l dint b..ep- p 41.4 11 1s4$38.50 without switchboard which would burn coal with an efficiency of I H. P. $84.50 2 H. P., III -211 colt.. Ito volts, 5 amp. $38.50 t11 rolls, A.O 275 watt1.21 rotta. $85.00 90 per cent; then we would only have to nwhinn, .tiding bu. $108.50 without swilchboud use approximately 1/12 of 60 tons, or 5 41 volts, 25 amp. $58.50 SH.P. N. P., 111 -221 tolu, 4102.50 221 volta, A.C., SII w.lta, 3 n. P., Il, .Odin lu. $124.50 N voli, with swilchboud $110-00 tons of coal I Likewise with the radium 111 l a 1 - rolls, .mp. $ 58.50 H. P., hllb speed, 1666 H. P., 111 -221 roll, R.PaseM, 21 instead of using five ounces to drive a train Morin. Picture $36.50 111 volt., AC.. 751 nwhion. didiR hue $164.50 : ph only' Are Generator $85.00O 72 vola, withaul swilchDNrd $125.00 between the two cities, we would only re- WRITE FOR CATALOG. BARGAIN: IN MOTORS AND GENERATORS quire practically 5/12 of an ounce! It SPECIA WASHING MACHINE MOTORS might be said at this juncture that, prac- ,alai' .75 tically speaking, but a very small fraction il.P.Ileroll.ÁC..60 c Small (;one cetr« of an ounce of radium would be required 1750 S.P., RPM. i rindere Bottle Complete,cord,plup d pulley Mother,' Etc. Bea Y.Ix M.el to do the work necessary to haul such a train at this rate, for undoubtedly when MONEY HACK GUARANTEE matter e o ae,t.c. D. by Egrew we once learn how to disintegrate SHIPPING TERMS: Sr t ddaw irth Brl o f n hIdbner aCg bD after such a fashion as this, we should have MANUFACTURERS. DISTRIBUTER available much more efficient motors, tur- CHAS. N. JOHNSTON, Box12 West End, Pittsburgh, Pa. bines and engines, etc., than we now dream of. In computing the amount of radium required, or five ounces in the present case, Send To -day for the the amount of heat assumed as required, $onorAf was that produced by the coal burning un- FREE! der the boiler. It will therefore be seen These phonograph needles Som - Permanent Silvtred "Electrical Worker's Friend" replace steel needles, play D E at once that this is really a very poor com- many times and are N E E L S An electrical book of 66 motor real effec- used on ALL MAKES of steel needle records. drawings with complete instruc- parison so far as showing the Economical, convenient, sweeten tone, and of radium (or atomic energy) ; preserve of 5, 40o In lions for rewinding and reconnect- tiveness records. 25e per card ing A.C. motors. Special at - means Canada, Write today for FREE sample. but as we do not have any other of Or write for full particulars of this valuable book showing this ratio in a practical sense, we Sonora Ilnnagrap1 Sales Cllmnpang, 3nr. SMITH & SMITH PUBLISHING (i F7(YRGE E. BRIGWrSON. President CO. ourselves with this illus- Dept. B. 1524 Lowrie St, N. S., Pa. have to content 279 Broadway. Dept. G, New York Toronto: Ryrle Bldg. Pittsburgh, tration. You benefit by mentioning the "Electrical Experimenter" when writng to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 935

4,000 - MILE EARTH RADIO SIGNALS. %SAVED Radiography is being revolutionized by G ETOUR transmission through the earth and water instead of the air, and recently gave re- BIG 500K I markable results at a little experiment sta- tion on a barge in San Diego Bay, said BURN LESS COAL Lieut, R. A. Morton, of the navy radio lab- With an improved, all -cast pipeless furnace you can cut your coal bills in two. This efficient. basement oratory at Mare Island, who conducted the installed heating plant heats and ventilates the entire home. It burns any grade of coal more economically experiments. than e. stove. It needs no ex- First proof of the success of the new pensive piping or other equip- ment. Anyone can install it in method of radio transmission thru the a day. They are described at our said, was made when wholesale prices in our Handy earth, Lieut. Morton Man Book. Send for it. the Navy Department sent a message from Do Your Own Plumbing and the Annapolis station to the British admi- Heating by the Cut -to -Fit ralty that the dirigible R -34 had been Method. sighted off the American coast. By our new plan anyone can in- Lieut. Morton was at his instruments, atall a complete plumbing or heat- ing plant in his own home. Send heard the messages and copied them in us a rough sketch with measure- entirety, he said. ments. Our Engineers will draw their your plans. furnish information and see that the supplies you or- der come CUT -TO -FIT your needs. No waste of time, labor or unused materials. Only a few Ilffeflic®píi:ele simple to6is necessary. Send for A Model By William J. Beach, M. E. The Handy Man Book (Continued from page 883) It will show you how. It will tell you just what to order and what it will cost at our wholesale prices. " "'ti It contains plans and useful i information for every builder, property owner or contractor. would be attempting to rise vertically at It will convince you. It will increase the value of your prop- the forward speed of an airplane and to erty 50 %. You can do the work up 100 m.p.h. is yourself. dream of going around We have spared no ef- rather visionary. What I claim is neces- fort or expense in the sary, however, is sufficient supporting sur- preparation of this valu- "I Can Succeed!" able book. To keep from face revolving in a circular direction at a sending it broadcast to "What other men have done with the uninterested persons we sufficient number of miles per hour ; as request a temporary de- the aerofoil or aerofoils of an ordinary help of the International Correspondence posit of 25c which will be re- direction Schools, I can do. If the I. C. S. have funded with your first order. plane are taken in a forward at can Send for It Today. a sufficient number of miles per hour for raised the salaries of other men, they The Service of example. raise mine. If they have helped others HARDIN -LAVIN CO. Having now described the advantages to advance, they can help me. To me, Is guaranteed by 40 years' and explained the principal requirements I. C. S. means 'I CAN SUCCEED. "' business at right now that not 4510 -206 Cottage Grove Avenue in a vertical rising aeroplane, I will pro- Make up your mind CHICAGO ceed to offer my suggestions as to how another day shall pass until you have they may be successfully carried out and made your start toward success. at the same time explain the principle of For 28 years men in offices, stores, my invention. shops, factories, mines, railroads--every- HB Make As already stated I consider that there where-have been winning promotion S00 Watt $100 to is a practicable way other than from the and increased salaries through the I. C. S. Battery $200 Profit center axis of a motor by which a sufficient More than 100,000 men and women are amount of surface may be rotated to rise now with I. C. S. help Charging Every getting ready right Month vertically and lift into the air a useful load. for the bigger jobs ahead. Set This, I suggest, may be done from the No matter where you live, the I. C. S. wi'.l come to outer perifery or at a sufficient distance you. No matter what your handicaps, or :low small of the motor your means, we have a plan to meet your circum- from the center axis or axes stances. No matter what career you may choose, or motors. some one of the 280 L C. S. Courses will surely suit A simple illustration may be had from your needs. the fact that if a large wheel were mounted When everything has been made easy for you - suitable axis and in suitable bearings, when one hour a day spent with the I. C. S. in the Big on a quiet of your own home will bring you a bigger Read This Record of human strength could not turn the wheel income, more comforts, more pleasures, all that Battery Charging Profits if the energy were exerted at the axis ; but success means -can you let another single price- Maxwell Garage, Lovington, Ill.: "Average weekly energy to be exerted at less hour of spare time go to waste? Make your income from battery charging is $40.00 to $50.00. once we allow the start right now! This is all we ask: Without cost, It costs about $10.00 per month to run our Charger." the outer perifery, then the feat becomes an way, put it up Electric Service Shop, G. W. McGee, Hamburg. without obligating yourself in any N. Y.: "Average monthly expense for current, easy accomplishment for human strength. to us to prove how we can help you. Just mark $7.00. Average monthly income from battery and mail this coupon. charging, $160.00." Linah Battery Co.. Carlisle, The reader immediately says "Obvious" - Pa.: "Average monthly income from battery charg- and in saying so, agrees with me that large a.la 11M EMI OM TlAf OUT Rene Wm taIM.=, ing, $133.03. Average monthly expense for cur- rent, $21.08." Southwest Auto Electric Co., Tuc- things are learned from small details. Hav- INTERNATIONAL CORRESPONDENCE SCHOOLS son, Aria.: "Average monthly income from battery ing agreed that a body may be rotated from charging, $165.00. Average monthly expense for BOX 6214, SCRANTON, PA. current, $40.00." Adams Cooper Sales Co.. Fort its outer perifery with a power that would Explain, without obligating me, how I can qualify for the Smith, Ark.: "My income per month from charger from position, or in the subject, before which I mark X. it $120.00-cost. $16.00." Hamilton Battery Co., be incapable of turning it its axis, ELECTRICAL ENGINEER SALESMANSHIP Hamilton, Ohio: 'Income per month, $200.00 to it now becomes necessary to apply that Eleetrle Lighting. and Rye. $240.00 -cost per month, $15.00 to $30.00." Elecuic Wiring Window Trimmer simple principle for the purposes already Telegraph Engineer Show Card Writer You, too, can make $100 to $200 outlined. Telephone Work Sign Painter CLEAR PROFIT each month MECHANICAL ENGINEER Railroad Trainman This H B 500 watt charger recharges 1 to 8 8 -volt According to the illustrations it will be . Meehenleal Draftsman ILLUSTRATING batteries at once for 10e to 15c each. Customer seen that a central nacelle has a bridge- Meehlne Shop Practice Cartooning Days $.75 to $1.50. No repairs, no renewals, no Toolmaker BUSINESS MANAGEMENT expensive bulbs to burn out. Simple, sturdy. work extending transversally from it ; the Gas Engine Operating Private Secretary economical. Absolute money-back guarantee. Small CIVIL ENGINEER BOOKKEEPER payment brings you this money- maker. balance on outer extremities of the bridge -work is Surveying and Mapping. Stenographer and Typiut easy monthly terms. Start NOW to build a big. provided with circular structures. Extend- HINE FOREMAN or ENG'll Cert. Pub. Accountant profitable battery business. Winter best time to STATIONARY ENGINEER TRAFFIC MANAGER, start. ing rearwards from the nacelle or fuse- Marine Engineer Railway Accountant Write today for full information. lage are spars or Dooms which carry or Ship Draftsman Commercial Law HOBART BROS. CO., Box IIE. TROY. OHIO ARCHITECT GOOD ENGLISH Successful Manufacturers Since 1803 support a horizontal stabilizer and a ver- Oontreetor and Builder Teacher Arehlte etnrel Draftsman Common Sehool Sebjeetsi tical fin and steering rudder. Concrete Builder Mathematics Structural Engineer CIVIL SERVICE Immediately above the two circular struc- PLUMBING AND BEATING Railway Mall Clerk tures are the uplifting surfaces secured to Sheet Metal Worker AUTOMOBILE OPERATING Textile O Supt. Auto Repairing Spaa central vertical shafts. The lower parts CHEMIST AGRICULTURE jL Eremite Telegraph Pictures of the circular structures are provided Navigation Poaltry Raising Italian BY ELECTRICITY with a track extending from the vertical Names Complete sets of two machines, of this shafts, on which the supporting surfaces marvelous equipment at ridiculously Present low prices. Instructive, mystifying are secured. There are also beams or the Occupation_ and useful. This picture of President like which carry at their extreme ends Wilson was telegraphed by these ma- Street chines. Will transmit pictures, maps, suitable motors, there being two in or on and No drawings and hand writing. Picture telegraphing is the coming science. each track ; the motors are preferably of City State Write today. the rotary type and placed in an inverted !. LEISHMAN CO. Dept.T Qgdes.01.1 manner for purposes mentioned later. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 936 ELECTRICAL EXPERIMENTER January, 1920

It will be observed that a circular part "The Bab-y" Heammerlesst nevo r' has been cut out of the horizontal stabilizer, A HANDSOME AND MOST EFFECTIVE WEAPON beneath which is located a continuously Measures but revolving stabilizer, the blades of which 4% Incheslong PLATINUM may be reversed at the will of the oper- VOMITS ator, but normally the blades revolve in MAGNETO a neutral position. The two uplifting surfaces revolve in é.óuGMT opposite directions, and since it is most desirable that they both revolve at uniform Tau MtMW - speed, or that they shall be perfectly syn- HIGHEST CASH PRICE At orllrs chronized, they are positively coupled to- Paid for Platinum -Old Gold Ttn"rind": w m Rove.. d e revolver«tw . u d Jewelry-Watches, Silver and Dia- """"ear mr. gether, so that should the one on the left wnñ.>a.haueidAe. ems 1tWttL+- 120 South State St., Dept. 73, CHICAGO, ILL beMUgahN - driven from this coupling and likewise the SHARPEN - M -ALL: p forward propeller if need be. SHARPENS EVERY KIND OF SAFETY RAZOR BLADE aImen with training are in de- Describing the invention in operation, mand. For more than a quarter Sharpens the Gillette and Durham Duple. both edges at one time Electric of a cottony. this school has dLSO SHARPENS THE GEM IUNIOR EVER READY. KEENJKUTTER. NARK the motors are provided with traction CROSS. CLARK. AUTOSTROP. STAR CRUSTEEL. AND ALL OTHERS been training men of ambition and limited time, for the elec- ,HAnrcn.rs.AU srnor.rn wheels which engage with the tracks and trical industries. Condensed course in Electrical race around same as already explained, :° transmitting their energy at a sufficient dis- Engineering cureee9goro d tance from the central axis of the sur- positions and promotions. Theoretical and Practical Elec- P.':. . h.na. °l: tricity. Mathematics, Steam and Gas Engines and Mechani- `. cal Drawing. install wiring and . ,h marlci faces to enable them to take the surfaces Students construct dynamos, around at a sufficient number of miles test electrical machinery. Course with diploma complete per hour to create a sufficient number of In One Year pounds per square foot "lift to create O y e r 3000 m e n trained. Thoroughly Price, 41.W postpaid, equipped fireproof dormitories, dining an elevating force more than equal to hall, laboratories, shops. SIMPLEX.. the weight of the entire flying machine. Free catalog. 28th year opens Sept. 29, 1920 The advantages of placing the motors in BLISS ELECTRICAL SCHOOL TTYPEWRITUri an inverted position is primarily for lu- 260 TACOMA AVENUE. WASHINGTON. O. C. -ONLY $2.50 reservoir may Cheep But Goed. brication purposes, as an oil Learn to recognize the marks that So Simple Child be provided in the bottom of the crank STUDY nature has stamped all over the Can Use It. We Guarantee case which is not practicable in a rotary HUMAN human form. Look through and the beyond the deceptive smile. Know Writing ; i'lgi h Wá motor revolving in the present airplane th:telke D. nm ¢,.wept. Z NATURE the strong and weak points of nenaie..w rye< f rw `. : sLÔá' reason is to take those meet. Send 5 cents in stamps for "PERSONAL ww it-_--'°'_'-' tfte prise, bue s rw. however, the principal you 'nee,.t With re..g.go, w. u..,13"134,. advantage of the gyroscopic action of the POWER," a little book that tells how. Address H. C. n r :°á ^ñ«ri: u.c.°: fit Kuss, Secretary Progress League, 31 Union Sq., N. Y. City. eelbi rareeúÌwansn3 motors which provide for a maximum of . : n thi m°Pñemwiti Yea can be cured, G.éthe Puf 'nÿle:rn-: o,t inherent stability, as it will be seen that quickly if you irn.iTéi°ó%ñé nw ei.

Ediñ@ed by e GernsbacK Don't Lose Your Rights Before disclosing your invention to any- as is of interest to inventors and particularly to one send for blank form "Evidence of In this Department we publish such matter to be signed and witnessed. those who are in doubt as to certain Patent Phases. Regular inquiries addrest to "Patent Advice" Conception" Such inquiries are publisht here for the benefit of all A sample form together with printed in- cannot be answered by mail free of charge. structions will show you just how to work readers. If the idea is thought to be of importance, we make it a rule not to divulge all details, in to do so. up your evidence and establish your rights order to protect the inventor as far as it is possible before filing application for patent. As Should advice be desired by mail a nominal charge of $1.00 is made for each question. Sketches Only one side of sheet should be written on. registered patent attorneys we represent and descriptions must be clear and explicit. hundreds of inventors all over the U. S. and Canada in the advancement of inven- Receiver. IGNITION DEVICE. tions. Our schedule of fees will be found reasonable. The form "Evidence of Con- (365) Merle Nantz, Battle Creek, Mich., hereby (368) Clyde Stewart, Beldenville, Wis., says: ception" sample, instructions relating to presents to us a scheme and diagram for an am- "I submit herewith a drawing of a proposed igni- obtaining of patent and schedule of fees plifying telephone receiver. It employs a small tion outfit. The drawing is almost self- explana- sent upon request. Ask for them,-a post transformer which acts upon the diafram (D) tory. The secondary coil, which could be similar card will do. simultaneously with the polarized magnets (E M), to the one used on wireless spark coils is fastened which are energized by the current from the sec- firmly to the cam shaft C. The magnets N S are, ondary of the transformer. In the diagram P is the primary of the transformer, S is the secondary of the transformer, P M a permanent magnet which may or may not be used. The greatest doubt is A(f iatgoonemNhgOrt to plug that the transformer will not be efficient enough to A VA frAsoiv ser. the electro -magnets properly. 255 OURAY BLDG., magnetize i aansííeff,efe*eir D. C. A. We do not think that the scheme is s47ffywe0 WASHINGTON. feasible, altho theoretically there are grounds for "nrininators of form Evidence of Conception" your contention. The reason is that a telephone f0e/19/Ae receiver diafram is pulled down in the exact ratio 09/VNOY S supplied. Other things being equal, of the current f- rare afore ni it will not help you to transmit the current as shown in your illustration. As long as you get a tag sufficient number of ampere -turns the diafram will be pulled down in a certain ratio to the current past thru the windings. USing a transformer would therefore not help you. On the contrary, due to the losses inherent an every transformer, the efficiency of the receiver would not be in- creased, but rather reduced. H Patents to Minors. H MAN WI (366) Robert W. Ashworth, Houston, Texas, This Patent Advice Inquiry Is Repeated This AN IDEA says. "I am fifteen years old and have an in- Month, as no Diagram was Publisht with It I a comprehensive, ex- vention which I would like to have patented. in the December Issue. offer Please let me know, if not too much trouble, how perienced, efficient service for old a person has to be to apply for a patent in of course, rotating all the time the engine is in his prompt, legal protection and the United States." operation. When the engine is on the compres- the development of his proposi- A. As far as we can ascertain there is nothing sion stroke the cam shaft moves up, carrying the in the patent laws in the United States that coil with it. On account of the magnetic field set tion. prevents anyone from obtaining a patent. As up by the rotating magnets a high tension current Send sketch, or model and descrip- long as a person is the inventor of a certain would be set up in the coil. I am rather in tion, for advice as to cost, search device the age will make no difference and a doubt as to how much current could be produced, through prior United States patent,. patent will be granted, even to a minor. but I should think if the secondary were larger etc. Preliminary advice gladly fur- This is as far as the Patent Office is concerned. than most secondaries on gas engine coils enough nished without charge. It should, however, be understood that a minor current could be induced. The device could also My experience and familiarity with would have difficulty in selling a patent until he be applied to automobile engines by means of a various arts frequently enable me to was of age, or unless he had a guardian appointed. special device, which I have. The question of accurately advise clients as to prob- timing the discharge could be solved by moving able patentability before they go to either the coil or magnets. any expense. Telephone Receiver. A. This seems to us a good idea, altho it Booklet of valuable information (367) Weldon Hampton, Chicago, Ill., submits should be tried out first in practise. We are also and form for properly disclosing several elaborate drawings of a telephone re- afraid that more magnets than shown will have your idea, free on request. Write ceiver, the principle of which is shown in the il- to be used in order to get a sufficiently strong today. mag- lustration herewith. The inventor calls it a spark. We also are afraid that unless the RICHARD B. OWEN, Patent Lawyer secondary receiver or a combination of a trans- nets are very powerful little current will be real- even a small 164 Owen Building, Washington, D. C. ized. When it is considered that 2276 -8 Woolworth Bldg., New York City spark coil takes as much as five or six amperes it will be realized that in order to get sufficient sa .a, M electro- magnetic flux the permanent magnet would have to be exceedingly powerful.

Before disclosing an invention, the inventor should write for our blank form "EVIDENCE ON CONCEPTION." This should be to us together with model or Unique Idea for a Telephone Receiver, Pos signed and witnessed and if returned sessing Primary and Secondary Windings. sketch and description of the invention we will give our opinion as mitter and receiver. It may be used for repro- to its patentable nature. Electrical cases a specialty. ducing the feeble vibrations in the receiver to illustrated Guide Book, "HOW TO OBTAIN A PATENT," stronger ones. From the illustration it will be Our Terms seen that two diaframs are used and that the request. Highest References Prompt Attention Reasonable receiver has a so- called primary and secondary. Free on The core of the primary is hollow and a fine wire A passes thru it and forms one electrode of the FREE microphone H. The incoming line current operates VICTOR J. EVANS & CO., Patent Attorneys the diafram D, which in turn vibrates rod A of COUPON the microphone. This operates microphone H, Philadelphia Offices: New York Offices: Chicago Offices: Pittsburgh Offices: Bldg. which in turn acts upon the secondary and the 1114 Tacoma Bldg. 514 Empire Bldg. 135 S. Broad St. 1001 -1007 Woolworth diafram K. An amplification thereby results. 779 NINTH, WASHINGTON, D. C. A. A very clever idea, and we think that a MAIN OFFICES: patent can be obtained upon it. We are certain that the device works and it would come in useful for many purposes. You benefit by mentioning the "Elettrica: Experimenter" when writing to advertisers. 938 ELECTRICAL EXPERIMENTER January, 1920

Rotary Spark Gap. (369) J. Russell Franty, Du Bois, Pa., sends in to us for patent advice on the following and Competent HOW TO MAKE says: I submit herewith a plan drawing of a Patent Service rotary spark gap which embodies a new idea in By a Former Examining Official MONEY WITH YOUR PATENT the manner of connection. The object of this is of the U. S. Patent Office HOW TO SELL. to increase the number of discharges across the HOW TO KEEP CONTROL gap per second with the use of a smaller number HOW TO ORGANIZE of electrodes. NORMAN T. WHITAKER HOW TO RAISE Referring to the drawing: MONEY R = rotating member. Made of bakelite or Lawyer and Engineer These and hundreds of other vital questions the In- other insulating ventor must know to make his invention a financial material. success, fully answered in B= a ring of copper or brass surrounding R. 480 Whitaker Bldg. Washington, D. C. C D, E, F, G, H, I, J, K = electrodes mounted Branch Office, 52 Wall St., New The Inventors' Manual of Valuable Information on B. York City, S S' S" = stationary electrodes. S and S' INQUIRIES INVITED $1.00 per copy, postpaid are similar to the revolving electrodes C, D, E, If you have a patent or are thinking of taking out one, etc. S" is of a rectangular form and is slidably protect yourself by getting all the information this mounted on a stud so that it can be moved closer valuable book contains. to or farther away from the revolving member. Write for free circular and table of contents. IC, K' = adjusting knobs of bakelite or hard G. E. Perry Company, Publishers, 13ZÁ Broadway rubber. N. Y. A = stationary electrode support. It is a T- PATENTS shaped member and supports the electrodes S S' S ". Inventors Invited to Write for Information The stationary electrodes S S' are connected and Particulars together and thence to one side of the high ten- Highest References. Best Results. sion circuit. The electrode S" is connected to Promptness Assured. eh Bak the other side of the circuit, WATSON E. PATEN FSEtISÉ When the high tension current flows into S it COLEMAN jumps across the gap into C, then passes thru Patent Lawyer W Book/M fór B into E and then jumps across a gap into S ". 624 F Street N. W. Washington, D. C. INVENTORS.. The rotor R moves in a clockwise direction, and MANUFACTURERS Inventors and when it has made 1/18 revolution the electrode G will have come opposite the electrode S', which YOU SOME IDEA being connected to the electrode S, will pass a 1NVENTORSHAVEN'Tthat you can't just work out? 111b111 current into G, thru the ring B to E and then Manuiacturers" across the gap Give us the idea -we will develop it for you. Me- UIRr.ae¢M into S ". The next spark will pass chanical and electrical ideas developed. 51%711 LINT10M, between S and K and D and S." The same cycle Experts in model and experimental work return mail FREE. of operation is repeated 18 times per second. and in perfecting in- B The advantage As due to the fact that each re- ventions. Designing and building labor-saving Write LACEYE LACEY volving electrode is used four times per revolu- machinery a specialty. Get in touch with us- tion, whereas in the ordinary gap they are we can save you money. Dept.K. Washington,D.C only ELK MFG. CO., INC. 1926 Broadway, New York Free Book on PATENTS MATHEMATICS MADE EASY Write today for a Free Copy of "How The Arcascope -the Combination Triangle to with a Brain -will multiply, divide, figure Obtain a Patent." Contains valuable in- percentage and proportion, solve all problems formation and in trigonometry and geometry, draw symmetri- advice to inventors. Tells cal Satires. plot arcs, etc. Superior to any slide how to secure Patents. Send rule. Simple to operate. Also i n c l u d e s a TRANSPARENT TRIANGLE, PROTRACTOR and How to model or sketch of your inven- THREE RULES. Used at Columbia University. tion for opinion of its patent- West Point, U. S. Aeronautic Schools, etc. Only 85 obtain able nature cents Postpaid. Order today before you forget. -Free. (20 years Dept. 1, L. J. LEISHMAN CO., Ogden, Utah a experience.) Talbert & Tal- bert, 4287 Talbert Patent Bldg., Wash- tMusic Lessons CompleteConservatory ington, D. C. Course by Mail Wonderful home study muele lessons under great American At-HÓmel and European teachers. En- ATENTS dorsed by Paderewski. Meeterteachers guide and coach you. If you have an invention and desire to secure a Lessons a marvel of simplicity and completeness. patent. send for our Free Guide Book, HOW TO wntenaming course you areinterested GET YOUR PATENT. Telle our Terms, Methods. The Object of This Rotary Spark Gap Is to Any Instrument in:Piano,HarmonyVoiee,PublieSchool etc. Said model or sketch and description for our opinion ncrease the Number of Discharges Across Music,Violin Comet Mandolin Guitar,Banjo or Reed Organ of Its patentable nature. the Gap per Second with the Use of a Smaller .-and we will send FREE CATALOG. SEND for It NOWT RANDOLPH & CO. Number of Electrodes than Usual. IlniversityE ztensionConserv1101366236Bind- MienBNg.,Chicago utilized twice. Hence the discharges are twice as Dept. 172 Washington, D. C. frequent as in the common gap. Hang Your Thus the number of revolving electrodes may be Own reduced and the pitch of the omitted wave still Lighting remain Fixtures high. Semi -Bowl $5.85. If the number of revolutions per minute is 3600 Plate & Ball 85c. and there are 9 electrodes on the rotating mem- 4 light shower $5.35. Completely wired ber, there will be 64,800 discharges across the Including glassware. Bend for new Record your invention. O o request I will forward to you ewith Essential of Invention". gap per minute or 1080 per second. The ordinary catalogue, complete line. with full information lt. use gap with 9 electrodes would only produce 540 the beat to secure patent protection. Prompt, discharges personal, efficient serviez, by a attorney -at -law, under the same speed. ERIE FIXTURE SUPPLY CO. having over twelve years experience in patent metiers. In practice the number of revolving electrodes C.P. FIaMBURNE, C McGill Bldpre-warWington. 324 could be 5 or 7 and the pitch of the emitted wave Sta. Erie. P. will be above 600. Please advise thru the Get up-to -date in Rove patent advice columns of leal save Tam, Monar, the ELECTRICAL EXPERIMENTER whether this idea I AeOR and MATERIAL by ueing C. L. PARKER would be of any practical value. Could a patent Electricians o 98 GENUINE BLUE PRINT DRAWINGS, containing 11 the Formerly Member Ex- be obtained? latest diagrams and connection. known In house wiring-every diagram amining Corps. U. S. A. This seems to us as a very good idea ami connection up- to-the- minute as used by first class electricians Patent and for wiring BOLLo, BURGLAR ALARMS, LIGHTS, ANNUNCIATOR, FIER PATENT LAWYER quite original to our mind. We are almost certain ALAALARMS and ECTRICLe GAS LIGHTING. These drawings are bound In the PATENTS that a patent can be obtained on this design. form of flexible book 19 x 121 for convenience in using on the job. McGill Bldg. At Send for them, and if they don t make you more efficient es a wiremarl least we have never seen a gap just like this de- and save you many time. their Bost es a contractor, return them and Washington, D. C. be ONE scribed before. As a precautionary measure, how- DOLLépostpaid. Send toe circulars on othev of drawings. Patents, Trade Marks, Copyrights, Patent Litigation ever, we would advise to have your patent attorney make a search for patentability. PATENT SPECIALTY COMPANY Handbook for Inventors, "Protecting. Exploiting P. 0. Box No, 583 San Francisco, and Selling Cal. Inventions," sent upon request. FRANCE TO EXPERIMENT WITH TIDAL POWER. Patents Promptly Procured Experiments to determine the practicality How to Get Rid of Moles of the Send sketch or model for use of tidal power to offset the coal A simple, safe home treatment -15 actual search shortage under which France is expected years' success in my practice, of U. S. Patents. Highest references. to suffer Moles (also BIG growths) Dry Up. Personal service. Moderate fees. Write for a long time will be carried out under government auspices in St. Briac Ask for Free Bechtel of Full Particulars for Free Patent Book. Bay, on the north coast of Brittany. GEORGE P. KIMMEL, Patent Lawyer Experiments WM. DAVIS, M. D. are also being conducted to 4140State Street Perth Amboy. N,J. 99 -B Loan & Trust Bldg. Washington, D. C. determine the possibility of replacing coal wholly or in part on the railways, in gas, water and power plants, and for domestic NTS purposes. The Petit Parisien states that LEARN WATCH the use of gasoline in the chief gas, REPAIRING Hand Books on Patents. Trade Marks, etc., ;ent water You can learn by free. 70 our modem and orig- Our years of experience, efficient service, and power plants of the public service is inal system of instruction every part and fair dealing, assure fullest value and protec- of the Watch Repairing Trade at home tion to the applicant. The Scientific American contemplated, and that a daily saving of as good or better should be than at a shop. You read by all inventors. 4,000 tons of coal for domestic can earn money while learnine nd secure use may well paying position or start In basin.. after MUNN & CO., 622 Woolworth Bldg., N.Y. result. This would require 60,000 tons of course Instruction. Good Washington éh repairrs ays and Office, 622 P St., Washington, D. C. f:from t20 to $95 per week. For particulars gasoline a month, possibly imported from DDIy to the h MINIM the United States. ee School of Watehmakine 166 Mason SI., Milwaukee, Wie You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 939

-Voice Thrower 10c Swi m iml. Po ®1 Lem to throw your voice into a TRUNK, / under the bed, out in the hall or anywhere. ` Lots of FUN fooling the Teacher, Janitor, Purified by EIle(C- THE Policeman, Parents, Neighbors, or Friends. tTice Rays. HEART THE VENTRILO By JOSEPH H. KRAUS OF THE is a little instrument that fits into the mouth (Continued from page 877) out of sight. BOYS or GIRLS can use it HAMMOND in conjunction with the above for imitating Interchangeable birdsand animals. Never fails. A 32 -page A person is instantly imprest by the bright book on Ventriloquism sent with the Ventrilo for 10 cents. blue glow at the far end of the pool and Type going over to investigate, sees the steril-. NEW FORD JOKE BOOK 1920 izer. Looking into the pool he can see the All the latest jokes on the Ford auto. Hundreds of bottom thru eight feet of water as clearly them, and all good ones. Spring a new one on your finely pol- neighbors. as tho he were looking into a Large book with cover ished glass, and ah ! what confidence he by mail, 10c has in "taking a duck" in the inviting waters glittering and sparkling in their purity. The device is constructed very simply. It consists of a tank of non -ponderous proportion, which tank contains three com- ROGEN X-RAY partments. Between the vanes which di- One of the Greatest Achievements vide the compartments is an opening, al- of Science and Invention. Price 10 cents lowing for the insertion of the ultra -violet WONDER. HERE, BOYS, is ray lamp, in to flow just what y o u -the water order Hammond want. With this instru- from one of the compartments to tht ment you can apparently see the other, must pass two of these lamps. The bones in your fingers. Think of the fun you can have with it. Sample by mail, TEN CENTS. drain pipe successfully prevents the over- flow of the water above the compartment vanes. In this way all of the water must "Many Typewriters In One" the sterilizer at least SKULL RING pass over or under For the Mathematician, Engineer, . Here is a handsome, up -to -date Chemist, Bing, representing a Skull and twice. The water constantly going in, Astronomer, Surveyor, Navigator -there is Cross -bones. Has stones in the forces the rest of the water along, and ayes and looks something fright- no typewriter like the Multiplex Hammond! ful. Women won't like it, but inasmuch as the last compartment has a The Multiplex does many things that no for men orb s it is a great low vane or partition, a miniature water other typewriter can do 1 novelty. Sample, by mall. 15s. fall is produced. The water then passes ! into thru the supply outlet pipe. The Mathematical Multiplex contains the Gee What a Wad! the pool characters and signs used for writing in This is STAGE MONEY The tank can sterilize about 300 gallons of water per hour, and perhaps even more higher and lower mathematics, and for Looks like the GENUINE engineering, mechanics, etc., as well as for STEFF. Some Green backs and may be obtained from it. some Yellow backs. Create a all the ordinary work that can be done on BIG sensation among y o u r any typewriter. Just note these fine styles friends. The girls will all be of Multiplex after you when they see the wad. As1;: .7t 0 type- BIG roll of 15 pieces by mail, e n With 10 cents. Erc1ì ; Jl IIl e aQA lt-li n Il Itj3 g TWO STYLES OF TYPE, or ENCHANTED BARREL Ahead. tiro to five different The Moat Wonderful Pocket Trick Made (Continued from page 885) languages, Carried on CHANGE A CENT INTO A DIME Ask your friend to drop a dime in the barrel. the machine AT ONCE. When he takes it out, Behold] It is a CENT. How easily this maneuver is executed is You make 9 cents every time you fool them. "JUST TURN THE KNOB" Never falls. They cannot get on to it. proven by the remarkable triple exposure Sample barrel , with directions, only.... loC photograph here reproduced. This picture and change instantly shows three exposures on one plate de- picting the Landreth Motor -boat turning from Roman Type, to Hindso Flower Pot Trick in approximately its own length while trav- Italics, or Miniature You have all heard of the great Hindoo eling "full speed" ahead! The exposures trick (making a plant grow out of a were made a few seconds apart and the Roman, Uri. 4u'L aeaut -t f tie flower pot right In front of an audience). boat made a complete turn in approximately This trick has puzzled the whole world &elri,A 30-e, or from En- for years until an old Hindoo fakir gave twenty seconds! it away. We send the whole outfit by With a few turns of the wheels the rud- glish to Greek, Russian, mail with full instructions for 15 cents. der plates are set in V- shape, as illustrated German, French, etc. in the chart and with the propeller running full speed ahead, the boat almost instantly Any other type or Lan - BIG VALUE for 10 Ois. stops and starts to run backward. The boat was brought from full speed forward to guage can be substituted 6 Songs, words and music; 25 backing in 9 seconds. With the reversing in a feu seconds. Pictures Pretty Girls; 40 Ways to gear originally installed on this boat it Make Money ; 1 Magic Book; 1 The above gives a slight idea of the versatility of Book Letter Writing; 1 Dream Book took 26 seconds to back. The reversing the Multiplex which has literally revolutionized and Fortune Teller ; 1 Cook Book ; typewriting -has changed it from monotonous com- speed can be controlled to any degree by mercial work to beauty of fine printing 1 Baseball Book, giving rules for increasing or decreasing the angular posi- the and games ; 1 Toy Maker Book; Lan- engraving. guage of Flowers ; 1 Morse Tele- tions of the rudders. The reversing mo- WRITE FOR FREE BOOKLET showing the graph Alphabet; 12 Chemical Ex- tion is imparted by a stream of water many languages and type sets of the Multiplex- periments ; Magic Age Table; Great thrown back against the rudder by the there's a type for every profession, every business, North Pole Game ; 100 Conundrums ; every science, including technical signs and sym- 5 Puzzles ; 12 Games; 30 Verses for Autograph propeller and projected thereby forward bols and chemical keyboard. Albums. All the above by mail for 1Oc. along the sides of the boat toward the bow. Fill out the Coupon and mail to us now - The speed of this water is sufficient to pro- before you turn this page and possibly for- Trumpet in Handkerchief pel the boat backward at about 30 per cent get. You incur no obligation. of the full speed ahead. Just how this is _ The Trumpet in the Handkerchief accomplished is shown in the accompany- has come to torment us. It is a startler. A small metal. trumpet ing detail drawing. It will be noted that Also -an Aluminum is ingeniously concealed in a there is a steel plate, or fin, above the rud- PORTABLE handkerchief. On meeting your which prevents the thrown back Model friends, after chatting awhile, you der water For Traveling -for home. Weighs take out this handkerchief and by the propeller to escape over the top of about 11 -lbs. Full capacity. Ask blowy our nose. It's like a sudden clap of thunder ! the rudder. This fin assists in directing for special folder. The ladies scream, and your male friends will think the water forward along the sides of the they heard the whistle of a steam engine. You can blame the hideous noise to your having a very bad boat. cold, and keep the fun up as long as you like. The manner in which this experimental THE HAMMOND TYPEWRITER CO. Price, 10c, 3 for 25 cents, by mail. boat was equipt with the new rudder is 1 589 East 69th Street New York City; shown in the photos herewith. It was dis- Nanin Any 3 for 30c Mailed with Catalog covered in these experiments that the angle of the supporting rod must be 90 degrees, ROYAL NOVELTY COMPANY or more, with the propeller shaft. Photos Please write your occupation below. 415 East Ave., South Norwalk, Conn. courtesy of General Electric Co. va111MONIIN-ate aga.-- . ---a You benefit by men Toning the "Electrical Experimenter" when writing to advertisers. 940 ELECTRICAL EXPERIMENTER January, 1920

DR. J. H. ROGERS URGED FOR NOBEL PRIZE. Radio A cablegram sent recently to Stockholm, Diagrams Sweden, may secure for Dr. James Harris and Rogers of "Underground Radio" fame, an Formulae honor which he well deserves and a reward in Loose Leaf Form that he has spent a lifetime in earning: The publishers of the CONSOLIDATED The cablegram follows: RADIO CALL BOOK have completed the preparation of diagrams Committee on Award of Nobel Prize in on:- and instructions Physics, Measurement of Capacity of a Condenser. Royal Academy of Science, (Substitution Method.) Calibration of a Variable Condenser. Two Diagrams and Stockholm, Sweden. Curve. No. 1 We ask consideration in award of prize Measurement of Inductance of a Coil or Circuit. in physics for Dr. James Two Methods-Two Diagrams No. 2 Harris Rogers, Measurement of Distributed Capacity of an In- Hyattsville, Md., discoverer of under- ductance. Diagram and Curve No. 3 ground and undersea wireless. Details Measurement of Fundamental Wavelength of obtainable from Baltimore Sun, South- an Antenna. Three Methods. Three Dia- I grams No. 4 ern Commercial Congress, United States Measurement of Wavelength of Distant Trans- Senator France, Georgetown University. mitting Station. Two Methods. Calibration [Signed.] of a Receiving Set. Two Diagrams No. 5 Measurement of Effective Antenna MARYLAND ACADEMY OF Capacity. SCIENCES, Two Methods. Two Diagrams No. 6 FRANCIS C. NICHOLAS, Director. Measurement of Inductance of Antenna and a Third Method of Measuring Effective Capac- While all the scientific world concedes ity Learn Drafting of Antenna. One Diagram. No. 7 that Dr. Rogers discovered, revealed and Measurement of Antenna Resistance. Substi- put to immediate practical use a secret that tution Method No, 8 Employers everywhere are looking for skilled Nature had hitherto Schematic Wiring Diagram of Regenerative Au- draftsmen. They are offering good salaries to concealed, no one hap- dion Receiving Set Suitable for Receiving start with, splendid chances for advancement. pened to think, before The Baltimore Sun High Power Undamped Wave Stations. Con- it, nections shown are those used in most Drafting offers exceptional opportunities a suggested of the Nobel prize in physics Navy to as a reward and Commercial Receivers No. 50 young man because drafting itself not only com- for his achievement. Table giving the value of mands good pay, but it is the first step toward LC (Product of In- The Nobel Prize Fund is administered ductance and Capacity) for wavelengths from success In Mechanical or Structural Engineering 300 to 20,000 meters. Inductance or Architecture. And drafting is just the kind of by a board of trustees at Stockholm, and in Micro - work a boy henrys No. 100 likes to do. There is an easy, delightful the income from it is divided into five equal Table same as above but with Inductance way in which you can learn right at home in spare in sums, of about $40,000 each, to be centimeters No. 101 time. For 27 years the International Correspond- awarded Schematic Wiring Diagram ence Schools have been giving boys just the train- annually December 10, the anniversary of of Signal Corps ing Type SCR -68 Radio Telephone Transmitting they need for success in Drafting and more the donor's death, and to be known as the and Receiving Set than 200 other subjects. Thousands of No. 51 boys have Nobel Prizes. The prizes Schematic Wiring Diagram of Type CW -936 stepped into good positions through I. C. S. help, are conferred but never were opportunities for what is considered the (Navy Submarine Chaser) Radio Telephone so great as now. greatest work and Telegraph Transmitter and Receiver. Let the L C. S. help you. Choose the work you of the year in chemistry, in physics, in No. 52 like best in the coupon, then mark and mail it. medicine or physiology, in idealistic litera- Schematic Diagram of Type S.E. 1100 (Navy This doesn't obligate you in the least and will bring ture and in the furtherance of the world's Flying Boat) Radio Telephone and Tele- you information that may start you on a success- peace. The trustees do not make graph Transmitter No. 53 ful career. This is your chance. Don't let it slip the These diagrams and instructions are the by. Mark and mail this coupon now. awards, but have designated various edu- most CLEAR, CONCISE, COMPREHENSIVE cational institutions of Sweden --TEAR OUT HERE to make and CONVENIENT form of instruction that them. The Royal Academy of Science, has ever been presented. They are printed CORRESPONDENCE SCHOOLS Stockholm, is chosen to award the prize in on pages size 81/2 x 11. BOX 6215, SCRANTON, PA. chemistry and that in physics. Complete Set of 14 Sheets Explain, without obligating me, how I can qualify for the P7 position, or in the subject, before which I mark X. Thus far only three persons in America MECHANICAL DRAFTING SALESMANSHIP as described, sent postpaid 1 STRUCTURAL DRAFTING ADVERTISING have won Nobel prizes. The late President C SHIP DRAFTING Show Card Writer Theodore Roosevelt ELECTRICAL DRAFTING Sign Palmer was chosen for his CONSOLIDATED RADIO CALL ARCHITECTURAL DRAFTING ILLUSTRATING share in bringing about peace between Rus- BOOK CO., Inc. SHEET METAL DRAFTING Cartooning sia BOILERMAKER DRAFTING BUSINESS MANAGEMENT and Japan in 1906; Dr. Albert A. Mich- 41 Park Row, New York, N. Y. BRIDGE DRAFTING Private Secretary elson, of Chicago, a German by birth but MACHINE DESIGN BOOKKEEPER ELECTRICAL ENGINEER Stenographer and Typist a resident of the United States and a grad- Eleetrie Lighting and Railways Cert. Public Accountant uate Electric Wiring TRAFFIC of the Naval Academy, won the MANAGER Boys, Build This Car. ThIs ants Telegraph Engineer Railway Accountant physics prize in 1908, and Senator Elihu littlo ear drives by e tor, Telephone Work GOOD ENGLISH Root can be built by spy Cr.boy Terra MECHANICAL ENGINEER Teacher received the Nobel Peace Prize for 35 Miles famished by se and are very Machine Shop Practice Common School Sabjeets 1912 because his of work in the pacification plaol and pries ilstofpaetesh w Gas Engine Operating Mathematics Asa how W build tala lad's car. CIVIL ENGINEER CIVIL SERVICE of Cuba and the Philippines. Surveying and Mapping Railway Mail Clerk per hour S'TA'TIONARY ENGINEER AUTOMOBILE OPERArG No Nobel prize has been awarded in Marine Engineer Auto Repairing physics since 1915 owing to ARCHITECT ['PLUMBING AND HEATING the war. Is Record Contractor and Builder Textile Overseer or Sape Dr. James Harris Rogers, of Hyattsville, Concrete Builder Navigation 8paslsb of this Structural Engineer AGRICULTURE Premix inventor of the underground and undersea CHEMIST ,S PoaltryRaiaing Italian 8YPHER MFG. CO wireless system of telegraphy, regarded as Car 168 Warren Street Name one of America's greatest war inventions, TOLEDO, OHIO. Present T-25-10 has made a discovery in physics and per Occupation fected a practical invention that makes him Street today a central figure in the scientific and No world. It is a discovery that gave the BIG MONEY SAVINGS FOR YOU City State United States opportunity successfully to Used and rebuilt motorcycles, single and twins, F. $26 to 1100. Used bicycle., 56.00; tan- transport American troops to the dems,goodorhing d. Continent order. New bi- Price and to continue to receive, continuously, cycles andwg motorcycles at Fac- NO CARBON -MORE POWER -LESS FUEL c tory prices. You save dealers' O4 telegraph messages from Europe after At- profits.. Motorcycle d auto- On market 5 years. Over mobile too, $3.00. 10,000,000 in use. Every lantic cables had been cut. end for ineofpartta ppDiies.empleb set guaranteed. Popular eetateg , eninger Cycle Co..ROchester,N.T. 'JIII' OILS EALING 45 thru service. Don't re- OAWOODS bore cylinders. "NO- i-rULT LEAK-0" makes good 115T0SgIN6 .,,s when others fail. Made . different. Give results no other ring can. Write for booklet. Order from PLAN SERIES OF RADIO nearest Jobber, or write direct. NO- LEAK -0 PISTON RING CO., Baltimore. -:d. STATIONS. Beware of Imitations. See that NO-LEAK-0 is on Perfected Gasoline Engines- EVERY PACKAGE, The Y. M. C. A. Radio %. 1 and 1% h. p. -for Farm Club of Sioux and Shop use. Price, $27.50 Falls, S. D., is very active. At present the and up. Also, WASHING MACHINES club has 32 members and more are joining We ship on trial. Send for Learn Autos and Tractors daily. Booklet and Special Offer. SIEVERKROPP ENGINE CO. Wonderful opportunities constant- 1401 -19th St.. Racine. Wls. ly offered trained men; we train Since the organization of the club a short you thoroughly to start your own while ago lessons have been given regularly business or make good money as motor expert, driver, shop fore- in the code and the fundamental points of man, etc. wireless, including construction of radio 5000 Graduates making stations and the use of the apparatus in good. Catalog Free. connection therewith. to INDEX 2Volumes Cleveland Automobile School, 1807 E.24th St., Cleveland, O. With the establishment of several wire- ELECTRICAL EXPERIMENTER less stations about the city, it is hoped that Contains 24 pages and shows every article of inter- the club will become more interesting and est that has been published since the inception of the TAMMERER magazine up to and including April, 1918. It is abso- SSend 10 cents for my remarkable have a greater appeal to the boys of the lutely indispensable to everybody interested in any book. "How To Stop Stammering." city. The varied phases of communication kind of electrical research work. Kill the fear of stammering. Postpaid Re education the key. present many opportunities for developing 15c The Hatfield Institute. IFFM. Swims aygdsgg.IL interest and knowledge of the subject. Experimenter Publishing Co., 231 Fulton St., N. Y. C. January, 1920 ELECTRICAL EXPERIMENTER 941

THE HEART OF THE WIRELESS An Amateur Station Without a Vacuum Tube is Years Behind the Times MARCONI V.T. $7. °O each Under agreements recently effected the Marconi V. T. is the only vacuum tube, or audion, which may be sold to amateurs, laboratories, schools of instruction and experimenters. The approximate operating life of the MARCONI V. T. is 1,500 hours.

Fleming Pat. No. 803684 De Forest Pat. Nos. 841387 -879532

FEDERAL -AUDIO FREQUENCY TRANSFORMER

Designed for use with the Marconi V. T. $7.10 Standardized Socket $1.50 additional

The Marconi Resistance, connected in the circuit between the grid and the filament of the Marconi V. T., is made in the following standard sizes:

%Z megohni, 1 megohm, 2 megohms, 4 megohms, 6 megohms. Resistances of any special fractional values up to 6 Standard Resistance, Complete $1.00 megohms can be supplied. Send all remittances with order to COMMERCIAL DEPARTMENT

NEW YORK MARCONI WIRELESS TELEGRAPH CO. OF AMERICA 235 BROADWAY, Retail Office and Exhibition Rooms -25 Elm Street, New York Sole Distributors for De Forest Radio Telephone & Telegraph Co. BRANCH OFFICES: Schofield Bldg., Cleveland, Ohio Insurance Exch. Bldg., San Francisco, Cal. 301 Commercial Bank Annex, New Orleans, La. American Bldg., Baltimore, Md. 136 Federal St., Boston, Mass. 109 South 2nd St., Philadelphia, Pa.

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. PWD®®Is®011®s®ea®942 ELECTRICAL EXPERIMENTER January, 1920 The Mt. WIlIls®rn IlOO- i ffgach RenectIlng WIRELESS MEN Tekescope 4 (Continued from page_889)_ ® effect it, however, and even the heat from the friction of grinding made it necessary and 1 each day to discontinue a AMATEURS work after cou- ple of hours. Another most elaborate series of tests was made each day to de- The Second Edition of the termine the effect of the previous day's grinding on the optical qualities of the glass. To carry out these tests a 60-inch Consolidated plane mirror was required, the grinding of which took nearly a year in itself. 1 HUGE LENS MIRROR WEIGHS 9,000 LBS., OR Radio 41/Q TONS. i When the polishing was complete the huge mirror was 12x/4 inches thick at the Call Book i edge, 101 inches in diameter and weighed 9,000 pounds. The surface is slightly par- abolic and yet at its center differs from a true spherical form by only .001 of an inch. A deviation of more than .000,004 of an Will Be Out Feb. 5 inch from the theoretical form calculated by the mathematician was positively not 1 permissible. Imperfections so minute are The only book in print offi- discovered by exploring the surface of the 1 disc with a ray of light and it was for this cially listing all the amateur purpose that the 60 -inch plane mirror was of Commerce. required. And thru the center of this won- radio calls as issued by the Bureau derful mirror a hole, several inches in di- 1 Meets a timely and urgent necessity among radio ameter, is drilled. This is used for viewing the image thru, as explained later on. and steamship companies, professional and ama- In the spring of 1917, eleven years after the order was given for the casting of the teur radio operators, and those having need of glass, and seven years after the grinding radio calls; began the mirror was ronounced fit for authentic and practical information on use and it was therefore silvered. The radio, telegraph and cable rates, special signals area of its surface is 8,012 square inches and the operation of silvering required 150 and general radio procedure. gallons of distilled water and 32 ounces of silver nitrat. In 15 minutes the deposi- tion of silver was complete. All Amateur Calls Listed For use in conjunction with the larger mirror two convex mirrors also had to be In addition every vessel and land sta- That new and great aid to navigation ground. These mirrors were of 29 and 25 tion in the world is represented and -the radio compass-is explained and inches aperture respectively and when listed alphabetically, according to is a unique feature of this publication combined with the larger mirror increase names of vessels or land stations, and which will be of special value to its focal length from 42 feet 3% inches to masters of merchant vessels. This 150 according to call letters ; Revision of and 251 feet. book contains all calls listed in the In the meantime other and equally impor- American coastal stations under U. S. new book to be published by the De- Naval control, tant operations were in progress, for tele- and their new calls. partment of Commerce. scope mirrors are useless without proper mounting and housing. The dome of the observatory built contemporaneously with Price $1.00 Prepaid the grinding of the mirror is 100 feet in diameter and 100 feet high. In its con- struction 650 tons of steel were used, all IMPORTANT of which had to be transported to the NEW summit of Mount Wilson, 6,000 feet high. Given To permit this it was necessary to widen Free with Each Copy the mountain road from 3 to 8 feet. Mo- A Wireless Map of the World in colors is given absolutely free tor trucks having extra water supply to with each copy. This map shows the locations of all the high prevent overheating on the steep grades powered RADIO stations, in the world, including the time were found necessary and 6 months were required to get the materials to the top. signal stations. In addition it tells at a glance how far away The larger parts of the telescope mounting any of these stations are. Of greater interest are the time were made in the Fore River Ship -yard at zones, which enable the amateur to compute instantly the Quincy, Mass., and the dome was built by the Morava Construction Works of Chi- correct time for the zone in which he is located from any time cago. signal station. The dome is made of metal and Is dou- ble- walled to insure more uniform tern- perature. The greater portion of the dome rotates, only the lower 28 feet being sta- Order Your Copy Today tionary. A huge central pier, surrounded Send Cash, Money Order or Check. Act quickly, by 40 others, comprises the foundation for as orders are the telescope mounting. Underneath the pouring in and the edition will be rapidly exhausted. All orders main pier is a 6-foot depth of sand. This filled in the order of their receipt and first come, first served. pier is of solid concrete and hollow. At the level of the ground it is 20 feet by 45 feet and rises to a height of 33 feet. In Consolidated Radio Call Book Co., Inc. it are three heavy floors, the uppermost of 41 Park Row, New York City which at a level of 25 feet houses the driv- ing clock and other parts of the mechan- This book also contains the advertisements of practically every leading com- ism. The pany in the radio pier is surmounted by a circular field. floor 52 feet in diameter. To exclude !411104110411041111040 411110411411111! III (Continued on page 944) You ! benefit by onentionina the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 943

Telemegafone

FOR RADIO The Most Efficient RECEIVING Telephone Receiver and Loud Speaker

The most rugged, simple and reliable instrument yet produced for the reproduction of sound For Radio, it is not only a most sensitive receiver when used with the head -set, but is also the most power- ful loud speaker manufactured. The powerful Magnavox Telemega- fone fills a long felt need of public speakers and places of amusement. The Magnavox Telemegafone enabled President Wilson to speak to 50,000 people at San Diego. The President's PRICE $75.00 Victory Loan message was trans- Connect AA to Radio Receiver and BB to 6 -volt storage battery mitted by radio telephone from an airplane and reproduced by the Mag- FOR MUSIC AND VOICE navox Telemegafone to 20,000 people assembled in front of the Treasury Building at Washington, D. C. Immediate Deliveries - Send for Bulletin

PATENTED IN U.S.A AND FOREIGN COUNTRIES PRICE $150.00 2701 -2759 East Fourteenth Street With attachment for Phonograph as-shown Oakland, California Operates from 6 -volt storage. battery

You benefit by mentioning, the "Electrical Experimenter" when writing to advertisers. 944 ELECTRICAL EXPERIMENTER January, 1920

The Livest Catalog in America The Mt. WiliSCO t73 Our big. new electrical cyclopedia No. 21 is waiting for you. Posi- Mesco Radio Buzzer 1100-En ch Reif ecti tively the most complete Wire - leas and electrical catalog in print today. 180 Big Pages. With Shunt Resistance 500 illustrations. 300 in- struments and appara- U. S. Navy and U. S. Army Standard (Continued from page 942) tus, etc. Big Treatise on Wireless Teleg. raphy." 20 FREE Course Radio Offi- aupone for our in 20 les- HE drafts this floor is surrounded with a metal 160 -page eons. FREE I cers of the NC F R E E Cyclope- wall 9 feet high. Wireless dia No. 21 Planes, after test- measures 7x5,4 ". MOVING PARTS WEIGH 100 TONS. Weight ih lb. Beau- ing all other tiful stiff cerera. buzzers, de- The telescope tube is 11 feet in diameter Bend 6 cents in stamps or cided to use and consists of 4 sections. The moving coin for which we will send the our latest Cyclopedia Catalog "Mesco" parts of the telescope weigh 100 tons and No. 21 as described. on their ra- 44\* this immense mass is supported by a unique ELECTRO IMPORTING COMPANY dio equip- system of mercury flotation. Two cylin- 231 Fulton St., New York City ment. T h e drical pedestals rest in cast iron tanks R -34 was with 1/8 inch clearance between pedestal equipped with two Mesco Radio Buzzers. and tank which is filled with mercury. A 20,000 Meter Long Wave Tuner Why? Because of its reliability and plunger device adjusts the mercury to any 3,000 Meter Arlington Tuner constancy in operation; greater output desired level. For driving this huge mech- 200 Meter Amateur Tuner efficiency; ease of adjustment; unaffected the axis car- anism the lower end of polar They work on any by extreme variations in weather con- ries a worm wheel having 1,440 teeth cut ditions; exposed wires eliminated. aerial or loop. Wir- with the utmost accuracy and meshing with ing diagrams on bot- Sparking is almost entirely eliminated, the driving train of the clock. scien- tom. Coils machine so that the energy lost in light and heat The driving clock, a marvel of wound and set in in the operation of other buzzers is here tific accuracy and mechanical perfection, w a x . No delicate conserved and radiated in the form of os- is 6 feet high and covers a floor space of tuning. Foreign or- cillating energy. 51/2 feet by 4 feet. The clock is operated is ders solicited. Cata- This buzzer maintains a constant note and is by a weight of 11/2 tons whose falling log free. Agents and recommended as an exciter for checking wave - governed by a pendulum. Every 12 min- meters where pure note and ample energy are dealers wanted. Price required. utes the clock is automatically wound. $15 delivered to you. The telescope and dome are operated List No. 55, Mesco Radio Buzzer from a desk at the 42 -foot level by means TRESCO, Davenport, Iowa Price $2.05 of a system of electric controls. Without leaving his chair the observer may point MESCO WIRELESS PRACTICE SET his telescope to any portion of the heavens and rotate the dome and platform at will. Universal Radio System In all there are 40 electric motors ranging Up to the minute radio apparatus for pro- from 1/20 to 71, horsepower and making gressive users who can recognize quality. a total of 50 horsepower with 13 miles of Send stamp for catalogue. wiring. To prevent temperature changes an in- Universal Radio Mfg. Corp. sulating chamber with walls of cork one Dept. W Elmira, N. Y. inch thick is built about the mirror cell. In addition fans circulate the air about the The Practice Set comprises a regular telegraph mirror and keep its temperature even. WILCOX PANEL key without circuit breaker, a special high pitch buzzer, one cell Red Seal Dry Battery, and four The telescope carries photographic at- SWITCH feet of green silk covered flexible cord. tachments and a spectrograph of great re- "The Beat" The key and buzzer are mounted on a highly finement. Much of its work will be done tI/2 In. Radius Postpaid Price finished wood base, and three nlekel plated bind- by aid of these instruments. Complete Switch, polished brass tlnlsh.500 ing Complete Switch, nickel plated ilnish 60o posts are so connected that the set may be mounting 25o used for five different purposes. At last when both mirror and Knob. turned and polished were complete came the very delicate task Switch points, brass finish 20 List No. Price the mountain Switch points, nickel plated finish 4o 342 Telegraph Practice Set, with Battery of transporting to the top of THE WILCOX LABORATORIES, Lansing, Mich. and cord $3.24 the precious disc of glass, without which Weighs 4 lbs. packed. all these years of patient toil and outpour- Price does not include postage. Apparatus, Raw Mate- ing of genius would be in vain. It was WIRELESS rials, Magnet wires, Combination Practice Set for Learning the a Herculean undertaking. Most carefully MESCO Mo. and Cont. Visual and Audible Codes motors, experimenters needs, novelties listed the glass was lifted from the grinding in our Catalogue C-3. Assure yourself of lowered into box prompt service and right prices by buying from table and an octagonal this world famed, reliable, Experimenters' Sup- lined with paraffin paper. Inside the paper ply House. 99 of every hundred orders re- carded wool and Brussels carpet were ceived shipped within 24 hours. Catalogue C -3 packed to lessen the danger from shock FREE on request. and heat. The cover of the box was like- THE NEWMAN -STERN CO., Cleveland, O. wise padded with carpet and wool and ! securely fastened in place. The box itself was wrapt in paraffin paper clampt be- Loose Couplers tween heavy timbers and provided with a Combination Loose Coup- This outfit is the only reliable instrument which ler Parts and iss. will enable students to become proficient opera- ring for lifting. The motor car which tors in the U. S. Naval Service, because it is transported it was lined with cushions in Send 3c stamp for lie, equipped with a buzzer and miniature lamp en- which were strong springs, and heavy Arnold Brature which is sure master both the visual and to interest you. abling the user to timbers were bolted to the bed of the car. audible signals quickly. 2082 Lexington Av. N.Y, List No. 52- Practice Set with Red Seal Then the ascent began and as all the world J. F. ARNOLD Established 1910 Battery and Cord $4.05 knows it was crowned with success. Weighs 4 lbs. packed. Price does not in- HOW A CONCAVE MIRROR PRODUCES AN clude postage. IMAGE. SUPERLATIVE We carry a Large and Complete Line of RADIO EQUIPMENT Standard Wireless Material Recognized by To understand the operation of a re- THE BEST HEY IN THE Experts as such with Competent Experienced flecting telescope it is necessary to know COUNTRY Wireless Attendants in Charge. 10 Amp. 87.75-20 Amp. 08.21 how a concave mirror produces an image. A three cent stamp will bring Send for the New Edition of Our Catalog W28 Unlike a plane mirror the reflected rays bulletins of this and other higher It is pocket size. contains 264 pages, with over 1,000 of light actually come to focus at some gr a de apparatus. illustrations, and describes In plain. clear language all THE RADIO ENGINEERING COMPANY, about Bells, Push Buttons, Batteries, Telephone and distance in front of the mirror and pro- Wireless Telegraph Material, Electric Toys. Burglar 22 St. Paul St., Baltimore, Md. and Fire Alarm Contrivances, Electric Call Bells, Elec- duce a real image. A real image may be tric Alarm Clocks, Medical Batteries, Motor Boat caught on a screen and it is not upright, Horns. Electrically Heated Apparatus, Battery Connec- tors. Switches, Battery Gauges, Wireless Telegraph In- as that of a plane mirror, but inverted. SEND TO -DAY struments, Ignition Supplies, etc. The production of such an image is shown in the accompanying figure. A line drawn For Catalog for Complete Line of Manhattan Electrical Suppy Co., Inc. to the middle point of the mirror and 17 Park Place, New York, N. Y. perpendicular to it is called the principal Receiving Apparatus CHICAGO ST. LOUIS axis. Now all rays of light coming to the 11.1 S. Wells St. 1106 Pine St. REMLER RADIO MFG. CO. SAN FRANCISCO Mission mirror parallel to the principal axis will 163 Sutter St. San Francisco, Calif. OFFICE: 604 St. (Continued on page 946) You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 945

A 240 Spark Note on 60 Cycles with three to four times the energy in your antenna and with a low decrement entirely inside government regulations -all possible with the "AMRAD" QUENCHED GAP $17.50 Our bulletin No. 12 sent on request tells how Altho within the reach of every amateur's means, this GAP is on par in performance with the finest commer- Folder giving com- cial quenched gap. Not only does it increase the plete specifications efficiency of your station three to four times, but is sent on request. economical to use because it can be operated without a motor, which effects a saving in current. Ask your dealer today to show you the AMRAD Quenched Gap. If he does not have it, order direct from us but send us his name

Keep out Makes DC like AC For the amateur who operates of trouble where AC is not available the You can meas- "AMRAD" ure your wave INDUCTION COIL length with ab- $28.50 solute accuracy Works as consistently as a trans- and no difficulty former with the Adapted for amateur use from the designs for the army signal corps coil, the AMRAD induction coil entirely overcomes difficulties "AMRAt" found in all other WAVE METER coils. $5. A special model is made for use with 32 In this very simple and reliable volt farm lighting device a flashlight bulb and direct outfits. reading dial give instantaneous and precise measurement of your Ask your dealer to wave. It entirely s h o w y o u t h e transmitting A M R A D induction eliminates danger of violating coil. government rules. Your dealer can supply you Folder giving complete details mailed Descriptive folder sent on request. on request

AMERICAN RADIO AND RESEARCH CORPORATION 21 PARK ROW, NEW YORK, N. Y. Laboratory and Works, Medford Hillside, Mass.

You benefit by mentioning the "Eicctrical Experimenter" when writing to advertisers. 948 ELECTRICAL EXPERIMENTER January, 1920 The Mt. WsIls®n Il®®- inch Re t 1 ctáa MIGNON "RW4" Telescope UNDAMPED WAVE (Continued from page 946)

as a Newtonian or Cassegrain telescope, RECEPTORS but it is in the latter form that it will be most frequently employed. As already stated two convex mirrors have been Loose Couplers ground for use in this combination. For putting these mirrors into position a special Loading Coils crane is provided. Variameters The actual mounting of the telescope on its axes follows the English type and is Amplifiers somewhat unusual in this country. In any NO telescope there are two axes -the polar axis and the declination axis. By rotat- "RW4," Size 12" x 9" x 632" Strongest, Most Distinct Signals ing the telescope on these two axes it may be turned to any point of the heavens. The polar axis, as shown in the figure, consists of a heavy rectangular yoke IMPORTANT -NOTICE parallel to the earth's axis and supported Ernest C. Mignon, inventor of the famous disc -core undamped wave by two pedestals, the north one bearing 40 receptor, is no longer connected with the Mignon Wireless Corporation, tons and the south one 60 tons. At the of Elmira, N. Y., or their successors-the Universal Radio Mfg. Corp. top of these pedestals are the cylindrical Address all communications for Mignon apparatus to tanks and the mercury system of flotation. Mounted on trunions inside this yoke is MIGNON MANUFACTURING CORPORATION, Newark, N. J. the telescope tube. The trunions constitute the declination axis and this is at right angles to the polar axis. By rotating the telescope tube about these two axes any DAMPED AND UNDAMPED WAVE heavenly body desired may be brought into .1\\O 04/4/. view. When this has been done, the large APPARATUS FOR ALL PURPOSES toothed -wheel at the lower end of the UPERIOR polar axis is thrown into gear with the Endorsed by Radio Department of D., L. & W. driving mechanism of the clock and the R. R. Co. SYSTEM object may be kept constantly in the field Write for Literature. 1GNON as long as the observer cares to look. Stars of course rise and set, just as the sun does, and since the clock turns on the MIGNON, MFG. CORP. ,!i: :! polar axis of the telescope at the same rate NEWARK, N. J. ,/ that the earth rotates, this must just com- pensate for the apparent motion of the star. The dome is also made to rotate at the same speed. The observing floor, too, may be raised and lowered to any level New Big -264 Page No. 13 ith the changing position of the telescope. Wireless and Electrical MT. WILSON'S SOLAR OBSERVATORY. DUCK'S The Solar Observatory at the summit of Catalog Mount Wilson, 6,000 feet above sea level, It will be mailed for 12c in stamps or coin which may be de- free from vibration and immerst in the ducted on first order of $1.00. Catalog 'not sent otherwise. dustless air and cloudless skies of southern Nv e regard this catalog as our greatest effort. It embraces every- California enjoys an unexcelled location. thing in wireless worth while. 172 pages with no waste space It is possible to photograph the sun 300 devoted exclusively to wireless instruments. Your amateur days in the year! Very much of its work friend will tell you that there never has been any wireless catalog will be done with the splendid spectro- to take place catalog of this company and above scopic and photographic attachments of the of all that you can absolutely the telescope. By means of photography depend on our goods. There is no need for any other catalog when you have it will reveal countless numbers of this big catalog. hitherto unknown stars. Not more A big improvement over our former model. Primary divided than 5,000 can be counted with the un- into four sections, with three aided eye. Up to the building of this dead end switches, greatly im- giant reflector there existed approximately proving selectivity. 219,000,000 telescopic stars ; but it is now Secondary divided into three sections, with two dead end believed that the population of the stellar switches, eliminating harmon- universe may be increased by at least 100,- ics. The change in the con- 000,000. With the spectroscope the ele- struction of the guide rod sup- port makes it possible to obtain ments in stars so remote that the light mak- a looser coupling. It is a won- ing known their presence left their surfaces derful improvement over our 1,000 years and more ago, may be known old model both in performance and appearance. $23.50. with as much certainty as tho they were Only analyzed in a terrestrial laboratory. NEW MODEL SBB. NAVY TYPE RECEIVING TRANSFORMER Furthermore the spectroscope will reveal the physical constitution of the stars, nebulae and comets. Their motion, too, is disclosed and it can be told whether a The secondary on our new type Arlington is divided into star is moving toward us or away from three sections with two dead us and with what velocity. end switches eliminating dead end effect and harmonics and giving greater selectivity. The end support is similar to that HARVARD DISCOVERS NEW STAR on our Navy type permitting a Another star has been discovered by the looser coupling. It is a beau- tifully finished instrument. Harvard College Observatory. It was an- nounced on January 8th that Miss Joanna Price only $10.50. C. S. Mackie of the observatory staff, in the course of her examination of photo- OUR IMPROVED ARLINGTON RECEIVING TRANSFORMER graphs of the milky way taken recently at Cambridge, had detected the new comet. WILLIAM B. DUCK CO., 230 -232 Superior St., Toledo, Ohio Its position is Right Ascension 18 hours THE 49 minutes 30 seconds, declination plus 29 degrees 6.3 minutes (1900). You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 949

The Radii® Compass "ASK ANYONE WHO HAS USED IT" By PIERRE H. BOUCHERON ff (Continued from page 907) "My Brandes Headset Never Gives Me a Headache (NAME ON REQUEST) (or magnetic field) the wave will strike both sides of the loop at the same time and The fitting and lightness are very important. The Brandes Headset excels an equal amount of energy will be induced in these respects. Special attention has been given to this feature. in both sides of the loop circuit, either in an upward or a downward direction, de- BRANDES WIRELESS HEADSET CLEAR TONE LIGHT WEIGHT DEPENDABLE SERVICE Score 100% efficiency in actual use. o Uni/ Sharp, Unblurred, Readable Signals "Superior" assured by Set, 2000 ohms, $7 'BRANDES MATCHED TONE " - fig. El Exactly matching the tone of both receivers in each set and thus eliminat- When the Advancing Wave Strikes Both ing all confusion due to unmatched harmonics. Sides of the Loop Antenna Simultaneously Headset use for ten the Resultant Current in the Receiving Set Is Buy a Brandes Superior and it critically days. Action Employed In Then, if it doesn't come up to our claims or your expectations, return Zero. This Is the it and your money will be cheerfully refunded. Test it-compare with Practise. TRIAL others -for sensitiveness, clearness, distance. Prove for yourself the pending upon which side of the sine wave fine quality, the "matched tone." The two diaphragms toned exactly first strikes the loop windings. Since alike, strengthen the signals and prevent blurring. Used by many U. S. the Government experts, and experts abroad; by colleges and technical the currents induced in both sides of OFFER schools; and by professionals and amateurs everywhere. loop are of equal field strength, they will meet and neutralize when the circuit is SEND 4c FOR CATALOGUE E. completed in the receiver, with the result 32 Union Square that the detecting apparatus will not re- C. B RA ND E S, Inc. spond. Fig. 3 illustrates this action, where Room 814 New York City, U. S. A. the flat front of the advancing wave, hav- lf'IRE_LE_SS RECEIVER SPECIALISTS ing reached the loop and induced currents on each side having an arbitrary current strength of, let us say 4 units, travel to the Complete Line of Brandes Receivers for those in Canada. Send stamp for Pamphlet "E" simultaneously and receiver, reach there Radio Electrical Supply Co., 43 McGill College Avenue, Montreal, P. Q., Can. neutralize ; thereby reducing the current intensity to 0. However, if the loop is swung 90 degrees so that its plane points in the direction of the transmitter, it is evident that the advancing wave, which as explained before is either rising or falling, TRACO QUALITY will strike the front side of the loop either at a higher or at a lower point than the RECEIVING TRANSFORMERS other side, so that the amount of current induced in one side of the loop will be Used the world over. Insist on the genuine, built by the current its originators. Substitutes are expensive, irrespective either greater or smaller than of design. We absolutely guarantee our tuners to give induced in the opposite side. the maximum signal volume. Delicate refinement, un- of all this is that when the interrupted service and high class work- The result manship unite to make TRACO tuners two currents nieet in the receiver, the the standard whereby all others are stronger will overcome the weaker and the judged. If you Dealer actuate the receiver. does not handle them, resultant current will order direct from us. Fig. 4 illustrates this condition where the LIBERTY DETECTOR advancing wave has induced an arbitrary VALVES. RADIO AM- current intensity of 8 units in the front PLIFYING PHONES, in the other type used by the side of the loop and 6 units UNITED STATES, side, the resultant being 2 units, which BRITISH and FRENCH is used to actuate the receiver. Of GOVERNMENTS, now latter In stock, for sale. course, in actual practise the difference be- Send stamps for tween the two currents is not very great The Famous 5A and 5C Models bulletins. for the comparatively small loop presents a very small surface to the advancing wave THE RADIO APPARATUS CO., Pottstown, Penna., U. S. A. of 600 meters. It will therefore, readily been seen that the farther apart the two r sides of the loop are spaced, the greater will be the difference of potential between the two currents, and this difference must- be of sufficient intensity to properly respond in the receiver, for that is the one made Learn Wireless use of in reading the bearings. Splendid opportunities now in The reason that the minimum current is the Merchant Marine. Big salaries. the one used to read bearings is because All graduates GUARANTEED good positions by one of the there is too broad a variation of the cur- largest Wireless Telegraph Com- rent intensity at the point of maximum, panies operating hundreds of ships difficult the to all parts of the world. RE- which fact makes it to secure MEMBER: We are the OLDEST, ideal intensity. On the other hand the cur- LARGEST and BEST EQUIPPED rent strength variations are very sharply school of its kind in New England, and have THOUSANDS of satis- defined at the point of minimum and there- fled graduates to our credit. THIS fore, a selective reading is more readily ob- SPEAKS FOR ITSELF. Day and tained. This condition can be better under- Evening classes. Advanced classes in Radio Theory and code. Start stood by referring to Fig. 5, which is Our prospectus for the asking any Monday. known as the "bilateral" characteristic curve of the loop. The heavy line in the You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. ELECTRICAL EXPERIMENTER January, 1920

center of the two circles represents the loop, which, while at that angle, is receiv- ing the advancing wave at maximum The demand strength where the undesirable broad in- Your for Radio tensity lies. As the loop is gradually swung, operators however, from 300 degrees to 270, the wave strength gradually decreases to a sharper Future both at sea degree, until when the loop has reached 180 and in land degrees, the current is practically zero. positions still persists. Bet- HAVE YOU A WIRELESS STATION? The reading is therefore secured just be- Wireless operating is no longer complicated or ter inducements are con- expensive. You can have your own wireless station fore reaching zero intensity and at a point completely assembled and be receiving messages where it is very sharply defined; i. e., at stantly offered. Our brief within an hour after you get a Gilbert No. 4007 Receiving Set. the minimum current strength. This mini- course equips you thor- This outfit. designed and built by an expert. a Radio Officer in the U. S. Army during the war. mum reading, pf course, is taken into ac- oughly for the best paying is a complete station of the latest and most ap- count on the compass dial and the compass proved type and will receive messages from stations positions. 300 miles away. The Loose Coupler included is pointer is set accordingly. not the old, obsolete type that pulls out of the box The Radio Compass as explained thus Terms but a compact instrument of the new enclosed moderate and pay- panel type, in a quartered oak cabinet. far is known as bi- directional; that is, it ments arranged to suit your The Book of Instructions included with the outfit gives contains full information about operating and tells general east- and -west, or north -and- circumstances. the location of Government and commercial wireless south direction and therefore is subject to stations-when they send messages- and how to receive them. an error of 180 degrees. This error is not SCHOLARSHIPS TO Gilbert Radio outfits are all illustrated and de- serious in land radio compass stations as scribed in our spegial Radio catalog-sent free on EX - SERVICE MEN request. If you wash to purchase it Gilbert outfit the geographical position of the station al -' immediately and your dealer cannot supply you. Call or write for descriptive write us direct. ways enables the operator to determine the proper direction in respect to sea and land. literature. The A. C. Gilbert Company For instance, if the Montauk station gave 311 Blatchley Avenue New Haven,. Cone. In Canada: The A. C. Gilbert -Menzies Company, a bearing of 330 degrees, which points di- Limited, Toronto rectly inland, the operator would know Y. M. C. A. In England: The A. C. Gilbert Company. 125 High Holborn, London, W., C. 1. quite well that the ship's position would be directly opposite, "in other words at 150 de- RADIO SCHOOL grees, as will be evident by studying the Marcy Avenue near Broadway scale of the Montauk station in Fig. 1. On Brooklyn board ship, however, it is quite another, matter and to be 'effective a radio compass Telephone Williamsburg 3800 must- be uni- directional. HOW BEARINGS ARE OBTAINED. Radio compass stations as controlled by roe the U. S. Navy usually Operate in WIRELESS_ units of EXPERIMENTERS three, and sometimes four and five, as in NAME. the case of the New York harbor ap- proaches and are operated by remote con- trol ; that is, all compasses are connected by telegraph wires to a control center, e.a.euc,a which supervises the activities of all out- lying stations. In the case of New York, Make Your Own this central point is situated in an office The Newest Things WIRELESS APPARATUS IN WIRELESS Are in These Three Books Just Off The Press ,.-W1 ;( fiTixat-- RADIO INSTRUMENTS AND MEASUREMENTS Every amateur should have this book as it answers the \p¡/ ,NRELES$S. questions you want to ask and covers all phases of ``NST .I.yt+' tun subject matter indicated by its title. -(ÿ1.'BEe:t,' _ RUCf10N Cloth Bound, 320 Pages. Price $1.25 THE WIRELESS EXPERIMENTERS' MANUAL By E. E. Bucher Mr. Bucher's latest book. The only one that compre- hensively covers all phases of wireless work, including the latest practices in both Radio Telegraphy and Telephony. Most complete text book on these subjects yet publi shed. Cloth Bound. Approximately 300 Pages. Price $1.75 HOW TO CONDUCT A RADIO CLUB By E. E. Bucher One of the most popular wireless books ever published. Covers parliamentary procedure, indoor and outdoor ex- SAVE periments. 5.000 -mile receiving sets. use of vacuum It's easy to make your own at home tubes and many other subjects. Paper Cover, 148 Pages. Price 500 with the aid of these 4 up-to -date THE WIRELESS AGE books that you can understand. Each A monthly magazine that will keep you posted on the up -to- the -minute things in wireless communication. has over 72 pages and over 60 illustra- Official organ of the National Amateur Wireless As- tions, 3 color cover, size 5 x 7 inches. sociation. LESSONS IN WIRELESS TELEGRAPHY is Here the Advancing Wave Strikes the Front Price Per Year $2.00 it course in the elementary principles which and Rear of the Loop at Diffierent Levels SPECIAL COMBINATION PRICE >ou must understand to obtain good results. and Induces Currents of Different Strengths. All Four for Only $4.50 WIRELESS CONSTRUCTION AND INSTAL- Hence the Resultant Current Will Have a WIRELESS PRESS LATION FOR BEGINNERS gives complete Measurable Difference of Potential. 1850 Woolworth Building, New York details with working drawings for making simple but good sending and receiving ap- building near the Battery, where not only paratus and erecting aerials, etc. radio compass operation is supervised but THE OPERATION OF WIRELESS TELE- A New GRAPH APPARATUS shows how to obtain all radio traffic as well. The procedure for best results and greatest ranges with all furnishing or obtaining bearings to or from VACUUM RECTIFIER TUBE kinds of apparatus, how to tune the station incoming or outgoing- vessels is as follows : to 200 meters, use a wave meter, apply for for Wireless license, etc. The ship calls "NAH" (call letters of Telephone EXPERIMENTAL WIRELESS CONSTRUC- N. Y. Radio) in the regular commercial absolutely the newest device on the market. TION gives details, with working drawings manner and special radio Does away with motor generator. It per- transmits the mits you use 110 60 for making more elaborate and efficient send- compass signal "QTE ?" (meaning "what to VOLTS CYCLES ing and receiving apparatus, complete sets, alternating current and rectifies this to di- etc. is my true bearing ? "). The radio compass rect current for the transmitting tube. 30E supervisor at the control station, by making Get our free descriptive circular 121 use of one of the local transmitters, then WIRELESS EQUIPMENT CO., INC. c Pacostphaid 1.20 SET 19 Park Place New York, N. Y. Less ,than the price of one telephone re- instructs the ship to "send MO for two ceiver. Order now while the supply lasts. minutes" ; the signal "MO" being a special one recognized by radio compass COLE & MORGAN, Inc. Publishers stations. CATALOG H Place, New After this the supervisor simultaneously Dept. 114, 19 Park York informs all outlying compass operators by Send 5c in stamps for your copy today and get on mailing list for future bulletins without means of direct telegraph wires controlled charge. 24 pages reliable apparatus, FREEWe are giving away hundreds of expensive wire -, Contains of less Instruments, electrical apparatus, supplies, by a master key, to secure bearings or di- standardized parts and raw materials. Com- etc., for selling a household article that goes like wildfire rections from which the ship is sending plete line switch points, knobs, switches, rod, because it is a genuine necessity and because it sells so aerial wire, etc. cheap. All of our premiums are guaranteed new and "MO" signals, usually on a wave length of perfect. We give you no junk, Send us your a and add re. and we SHOTTON RADIO MFG. COMPANY, P. 0. Box 3, Scranton, Pa. will Bendy twelve articles prepaid complete information and pre- either 600 or 800 meters -Soo meters to be nipm catalogue. Branch: 8 Kingsbury St., Jamestown, N. J. L Book Novelty House, 1298 Carroll St., Brooklyn, N. Y. used exclusively after April 1, 1920. You benefit by mentioning the "Electric2l Experimenter" when writing to advertisers. January, 192U ELECTRICAL EXPERIMENTER 951

When the ship has concluded transmis- sion of the "MO" signal it is then in- structed to "QRX" (stand by), after which the supervisor obtains the respective bear- AUDIO FREQUENCY ings secured by the compass operators; i. e., Mantoloking, N. J., Sandy Hook, N. J., Island, L. I., and Montauk, L. I. All TRANSFORMER individual bearings are then plotted on a Type P specially prepared chart similar to Fig. 1, This transformer provides a maximum of low frequency amplification and is superior to all others. It may be used with the Marconi and all standard vacuum tubes. Permits reliable daylight reception from Euro- pean stations. Establishes new amateur long distance records. Renders remarkable amplification of all signals. Price $7.00 postpaid

The Current Strength Variations in the Radio Compass are More Sharply Defined at the Point of Minimum and Therefore a More Selective Reading is Obtainable Than if the Vacuum Tube Socket Maximum Strength of Signal Were Used. (Type Triode F) The base of this socket is Bake- and the resultant position will be the point lite dilecto and will not crack and of intersection of all combined bearings. break like the moulded material of An example of this is shown in Fig. 1. The the usual socket. bearings are then transmitted . to the vessel Contact springs are stamped with identifying letters. Base is pro- in the following form : "QTE (your true vided with three rubber feet and bearing is) at (whatever time four countersunk holes for panel the observation is made) 186 degrees from mounting. Montauk; 132 degrees from Fire Island; Price $1.25 postpaid 112 degrees from Sandy Hook ; 96 degrees from Mantoloking (signed) NA13"...It is EATON OSCILLATORS TWO STEP AMPLIFIERS then an easy matter for the navigator of DAMPED AND UNDAMPED the vessel to plot the bearings on his own RECEIVERS chart and thus secure his exact position! FARADON MICA TRANSMITTING CONDENSERS The complete operation from the time of call to the transmission of result is usually WIRELESS SPECIALTY APPARATUS CO. accomplisht within five minutes. Not only ENGINEERS, DESIGNERS, MANUFACTURERS is this information valuable to the naviga- tor but is also made use of extensively by Boston, Mass., U. S. A. various agencies on land . concerned with the movements of naval vessels, transports, revenue cutters, cargo vessels, etc. In the case of incoming passenger vessels, their positions are telephoned to Customs, Post TYPE Y673 Coupler Office, Immigration and Ship News officials in order that' steps be taken to meet these 260 to 3000 meters vessels at the proper time and make other necessary preparations. Price $14.00 FUTURE OF THE RADIO COMPASS. Camb. Rectifier, for The radio compass has come to stay. Every day news comes that one or more storage battery stations have been erected at various points of American and foreign coasts. Canadian, charging French, English and Italian governments $22.00 have erected radio compasses at important Price shipping sections and are co- operating with Type -Y673- Coupler the United States in order to make the service uniform and popular with skippers of both of merchantmen. In fact, an international Three -cent stamp brings bulletins radio compass conference will probably be these instruments held very shortly where standard wave lengths, methods of furnishing and secur- CLAPP EASTHAM CO. ing bearings, special abbreviations and 131 Main Street, Cambridge, Mass. other details of procedure will be adopted for international marine use. Masters of Pacific coast representatives: Remler Radio Mfg. Co., San Francisco vessels are gradually learning of the safety Canadian representatives: Radio & Electric Supply Co., Montreal Rectifier and advantage gained by the use of the radio compass during bad weather or fog, when other means of ascertaining positions are unavailable, and judging from past WANTED performances, it is estimated that fully 50,000 requests for assistance will be made 1800 Men,18 to 35, to become by vessels during the coming year. This Railway Mail Clerks equipt Service is open gratis to any vessel a FRANKLIN INSTITUTE, DEPT. N 101, ROCHESTER, N. Y. of what Commence $1300 year with radio apparatus, no matter Rapid advancement to higher Government This coupon, filled out as directed, entitles the sender to free specimen questions; a free copy of our book, "Oovemment Posi- tonnage. . Modern nautical nationality or Positions. "No lay -offs" because of STRIKES. tion" and How to Get Them." a list of Government positions schools have included the radio compass as THE POSITION IS YOURS FOR LIFE. now open, and to consideration for Free Coaching for the posi- curriculum for navigators. Country residents and city residents stand tion here checked. part of their the same chance. Common -sense education Great sums of money are being expended sufficient. Pleasant work, traveling much. COUPON by various governments to develop Paid vacation. rk..... yearly .. Postoffice Clerk (E12ÚÓ -166Ó) ..Intonal Revenue (5 900 518800) this new art and make it 100 per cent ef- Write immediately for free list of Government ,. F'oetoffire Carrier (51200 -51880) ..Stenographer 181100- $1800) positions now open. Don't delay. Every day ..Rural Mail Carrier 18 92042160) ..Clerk h the Departments at Weehington - 1 ;1100 -81800 ficient, and there is no doubt that in a very you lose means the loss of just so much chance ..Bookkeeper (81100-81800) short time it will be as indispensable a part of your early appointment. of the world's merchant marine, as the FRANKLIN INSTITUTE, Dept. N 101, Name lighthouse service has been for centuries Rochester, N. Y. (Address past. Vim this before you lose dt. Write plainly. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 952 ELECTRICAL EXPERIMENTER January, 1920

MURDOCK No. 55 The EIlech-l1CcaIl MacchIlhást RADIO By H.WINFIELD SECOR OPERATORS (Continued from page 903) $125.00 per month and ture core are good and tight on the shaft, upward plus so that some of them will not move when all expenses. being turned or filed and thus cut into the winding and short -circuit it, "the operation Modern Equipment is usually successful," as the doctor would - say. Special Short Course REBABBITTING OF WORN BEARINGS. Individual Instruction The usual practise in repair shop work Finest Staff of teachers and also in the manufacture of some mo- tors and dynamos is to babbitt the bear- available ings. Babbitt metal is a mixture of sev- eral metals in the following proportions :- Dormitory -Swimming Tin-50 parts copper -1 part; antimony Pool 2000 Ohm Set $4.50 -5 parts. Phosphor bronze contains: Copper -79.17 ; tin-10.22 ; lead -9.61, and Call or write for 3000 Ohm Set 5.50 phosphorus -.94. A mixture for an anti - illustrated booklet friction metal is :- Lead -88.32; antimony WHY PAY MORE? -11.93. Y. M. C. A. Radio School Here are receivers that will respond to The pouring temperature of the molten Dept. R. the feeblest signals. They are un- babbitt metal not should be allowed to ex- 152 E. 86th Street questionably ceed 470° Centigrade. The simplest shop New York, N. Y. test to determine when the babbitt metal is "BEST RADIO SCHOOL IN THE EAST" SENSITIVE hot enough for pouring, is to stick a piece Here are receivers so rugged in con- of paper or a splint of wood into the bab- struction that they will keep their sen- bitt metal for a second, and if it bursts into sitive adjustment longer than any flame, the metal is at the correct tempera- others made. They are unquestionably ture for pouring. For first class work of 3 -INCH DIAL course, some form of electrical or other DURABLE regulator is necessary to keep the tempera- INDICATOR ture of the molten babbitt metal at an even Here are receivers fitted with every degree or between the limits of 460 to 470° accessory tending to comfort and con- Centigrade. The metal should be stirred Black Composition venience. They are unquestionably thoroly by means of a ladle at frequent in- tervals, or otherwise the heavy metals will with Brilliant COMFORTABLE settle at the bottom of the pot, also the White Filled Engraving Here are receivers designed to have skum which gathers at the top of the mol- 100% perfect appearance. They are ten metal should be removed from time to Dial No. 66 only postpaid unquestionably time and to prevent oxidation the molten $.75 metal should be kept covered with a light GOOD LOOKING layer of charcoal or grafite. Dial No. 67 with Bakelite They fill every requirement in every One of the accompanying illustrations Knob, postpaid, $1.30. respect, at prices considerably under shows a clever self- skimming ladle which any obtainable anywhere. is provided with inside bridges which pre- For Sale By All RADISCO Agencies determine the size of the metal stream in WHY PAY MORE? pouring, and for preventing skum from the and by top of the ladle getting into the bearing. The demand for our receivers and Leather holders to protect the hands in A. H. CORWIN & CO. other MURDOCK apparatus has been holding the ladle are shown at the right so great that we advise early orders if of the figure. In pouring babbitt metal into 4 West Park St., Newark, N. J. you wish to secure prompt service. the bearing, the bearing being invariably Bulletin 19B sent free on request stood upright for the purpose, as shown in Fig. 3, you should pour from the ladle in a steady stream, directly down along the MARMO WM. J. MURDOCK CO mandrel or shaft, to avoid splashing or pocketing air. lip STORAGE BATTERIES of The of the ladle ARE GOOD -TRY ONE 55 Carter Street, Chelsea, Mass. should be kept free from burrs or other 503 Mission Street, San Francisco surface irregularities in order to pour a Paul M. Marko & Co., Inc. smooth, round stream. If the hot metal is 1402 -1412 Atlantic Ave. splashed against the shaft, it will cause Brooklyn, N. Y. blow -holes and give a "mushy" bearing. Referring to Fig. 3 -A, this shows a corn - WIRELESS AMATEURS mon type of bearing in which the inner SELENIUM CELLS Send a 2c. stamp for full description of lining is formed solely of babbitt metal. Made by entirely new process. Highly sen- If a sitive and quick- acting. Suitable for all ex- The Barr Mercury -Cup Detector such bearing has to be relined with periments. From $5 up. this metal, it is placed in a gas stove flame Write for Catalog the most efficient detector in the wireless field- or that from a gas blowpipe, until all the today. old babbitt metal is melted out. It should Selenium Laboratories Good Ground, Long Island, N. Y. Tested by Marconi Wireless Telegraph Co. and be thoroly cleaned and scraped inside and U. S. Government. several small holes are drilled thru the Increases the efficiency of every wireless receiv- brass shell, as at C, into which some of the FREEOur catalog covering a ing set by making the signals clear, sharp and molten metal will run and help to lock the distinct. Instantly adjustable at a constant new babbitt lining into place. Over these complete line of Bargain pressure. openings a piece of asbestos can be tied "Better Quality" Wireless Apparatus. tightly and into the set screw and oil holes Send today-Do not hesitate. THE BARR MERCURY -CUP DETECTOR at the top and bottom a piece of wood can Dept. A, The Wyoming, Washington. D. C. be tightly threaded. The bearing is then The H. S. Wireless Co. usually set upright on a piece of asbestos 164 Ross Street - Brooklyn. N. Y. and packed around with wet fire clay or la putty, 158 Genuine Foreign Stamps -Mexico War as shown at Fig. 3 -A. For small [Be From sues, Venezuela, Salvador and India in bearings that is all that's necessary, service, Guatemala, China, etc. Only and no A MRMEE R i N Finest Approval Sheets 50% to 60%. AGENTS shaft or mandrel is placed in the center ; ST G WANTED. Big 72 -D. Lists Free. We Buy Stamps. Home Exercise Course. Results GUARANTEED or Established 25 yra. when the newly poured bearing is cooled, NO PAY. Write for full particulars. Hussman Stamp Co., Dept. 67, St. Louis, Ms.. it is then "chucked" in the lathe and bored I Sutherland Course, Educational Bldg., 70 -5th Ave., N. Y. January, 1920 ELECTRICAL EXPERIMENTER 95 3 The ORIGINAL and reamed out to fit the shaft. When a bearing is of good size, however, two methods of procedure are followed : Your Choice AUDIOTRON In an emergency, as for instance where ADAPTOR the bearing is sometimes to be rebabbitted right on the machine, without removing 50c a Week the shaft or housing, the molten babbitt $1.75 Each metal is poured into the properly prepared Shipping Weight One Pound bearing housing and allowed to cool Your Tubular Bulb will against the shaft, which is to turn in it, now fit the standard "VT" without giving excessive play when it is socket with our adaptor cooled. Where a first class bearing is de- sired, with regard to a close fit, so that the shaft just turns freely in it when it is fin- New Type "VT" Socket ished, the procedure is then to use a man- Now $1.00 Each drel slightly smaller than the shaft, and this is accurately placed in the center of FREE! base with With every set Is Included - Our adaptor consista of a standard the bearing. When the molten babbitt FREE-a Consulting Member- nickeled brass pillars appropriately placed to ac- ship which gives you the priv- commodate five leads and support tube. Pillars are metal is poured in there will be a hole thus ilege of submitting your per- forced into solid bakelite, not sealing wax. in somewhat' plexing problems to a corps of left the center of the bearing, experts for an entire year. This We have PARAGON back -mounted rheostats, $1.75 smaller than the proper size to fit the jour- Consulting Membership regular- sells for New radio call book out Jan. 15, '20, $1.00 each nal which is to run in it. The bearing is ly $12.00. RADIO EQUIPMENT CO. then placed in the lathe, carefully centered 630 WASHINGTON ST. BOSTON, MASS. as regards the outside supporting surface No matter what your occupation, one of the bearing, drilled or bored out with a of the home study sets listed below will The "ACE" boring tool to nearly the required diameter, quickly fit you for a better job and bigger pay. Any set then if a first class finish is desired, you select win be sent for seven days' examination, and if and you decide to buy you may pay the rock- bottom price at Vacuum Tube Socket reamed out zuith the proper size reamer. the rate of only 50o a week. But you must act nowl The Designed to fit the Standard four prong vacuum Fig. 3 -B shows a bearing set up ready rising cost of paper and binding materials won't permit us tube. The top part is a finished aluminum to continue the present low prices much longer. casting mounted on a formica base one -quarter for pouring, and in which there has to be These books are the work of recognized authorities. inch thick. This base will not break under any secured by the babbitt metal filling, a bear- They are written in plain, easily understood language by condition of service, as moulded composition recognized authorities, and contain hundreds of photo- bases will Heavy phospor -bronze springs are ing sleeve which is often of phosphor graphs, diagrams, tables, etc., that 'make difficult points mounted on the under side of the base for con- bronze, brass, steel, or even iron pipe. This as simple as A -B -C. Handsomely and durably bound In nection to the tube prongs. This is the only vacuum half or full morocco leather (except as noted), and tube socket on the market which has the grid leak is in place by means built in as part of the socket. It may be used for sleeve held accurately stamped in gold. back or front of panel mounting. The best socket of a shaft or mandrel carefully centered on the market regardless of price. and held by jigs or clamps, together with $1.50 each rs complete the bearing, onto the base plate of asbestos Pay -Raising Books with grid or else a metal plate on which rests a piece leak of asbestos. In this case the sleeve should Greatly Reduced Prices is in at W e have its outer surface, which to be -is. menu- Carpentry and Contracting, 5 volumes, ' 2138 pages, , facture a contact with the babbitt metal, thoroly 1000 pictures. Was $25.00 Now $19.80 -,.. .".-2 complete tinned, and it should also be heated before Civil Engineering, 9 volumes, 3900 pages, 3000 Pic- line of Ra- twos. Wag $45.00 Now 29.80 being placed into the bearing ready for Prevention and Insurance, 4 volumes, 1500 dio appara- Fire pouring. One clever make of electric mo- pages, 600 pictures. Was $20.00 Now 15.80 tus. Electrical Engineering, 8 volumes, 3800 pages. 2600 tor utilizes a cast iron sleeve for a bearing, pictures. Was $35.00 Now 24.80 THE PRECISION EQUIPMENT CO., INC. Automobile Engineering, 6 volumes, 2600 pages, Manufacturing Engineers which the manufacturers claim they have 2000 pictures. Was $30.00 Now 19.80 2437 Gilbert Ave. Cincinnati, Ohio satisfactory for cool running Machine Shop Practice, 6 volumes, 2300 pages, 2500 Dept. E found very pictures. Was $30.00 Now 19.80 and even wear. Steam and Gas Engineering, 7 volumes, 3300 pages. recommends 2500 pictures. Was $35.00 Now 21.80 The Westinghouse concern Law and Practice (with reading course), 13 volumes, AMERICAN ELECTRO the following procedure for bronze, pipe, 6000 pages, illustrated. Was $72 Now 44.80 Telephony and Telegraphy, 4 volumes, 1728 pages. TECHNICAL APPLIANCE CO. or steel shells (tinned) :- "Remove the old 2000 pictures. Was $20.00 Now 14.80 235 Fulton Street New York City lining by heating, preferably in a pot of Sanitation. Heating and Ventilation, 4 volumes, 1454 pages, 1400 pictures. Was $20 00 Now 14.80 scrap babbitt, and be sure not to heat above Practical Accounting, 4 volumes, 1840 pages, 800 375° Centigrade. Just as soon as the old pictures, etc. Was $20.00 Now 14.80 Drawing, 4 volumes, 1578 pages, 1000 pictures, blue lining is melted out, swab the tinned sur- prints. etc. Was $20.00 Now 14.80 face with zinc chlorid (a saturated solu- tion of zinc in hydrochloric acid), then dip into a pot of "half and half" solder, which should be kept at a temperature not Send No Money -- Switchtit Points, not more than 375° C. Gap. 18c per Doz. less than 340° C. and Shipped for 7 Days' Trial Spark $1.10 If shells are to be babbitted immediately, All Parts for the Amateur to Build His Own Yes, we'll gladly ship any set right to your home or Sets, Complete Coupler, Parts, Tuners, Cabi- do not touch tinned surface after remov- office upon your simple request. Pay only shipping charges ing from the solder pot. If the shells are when the books arrive. Don't send a penny until after net Sets to Build. Etc. you have used them seven days, then remit only $2.00 or cool, brush off the tinned Pay balance at the rate of DE FOREST'S APPARATUS ALWAYS ON to be allowed to return them at our expense. $2.00 a month -50c a week. HAND surfaces with a piece of clean waste." Act now -while these splendid books are being offered at 20%v to 30% less than regular prices. This offer is BEARINGS. open to every person within the boundaries of the II. S. GROOVING REBABBITTED and Canada. Grasp your opportunity -1111 in and mail the coupon now! Fig. 4 shows how oil glands or grooves Radio Amateurs Wanted in babbitt lined bearings and to represent us in your town and vicinity. Work are tooled American Technical Society, Dept. X251, Chicago consists of calling upon our prospective students and also one form of hand grooving tool. The telling them about the N. R. I. Ten Weeks Home Study . Wireless Course. Liberal commissions allowed. We grooving tool is made of tool steel forged furnish names and addresses to call upon-and printed out to the shape shown, either from square, American Technical Society, Dept. X251, Chicago, U.S.A matter for free distribution. Write at once for ex- 1 clusive rights in your section. National Radio In- round or hexagon stock, and it is usually stitute, Dept. 162, 14th & You Sts., Washington, D. C. curved slightly upward along the length of Please send me set of the tool. For small bearings the tool is about five inches long, while for large bear- WIRELESS is provided with or ings the tool sometimes for 7 DAYS' examination, shipping charges collect. I On account of increased demand for Radio else forged onto a long, low grade piece of will examine the books thoroughly and, if satisfied, Operators, we have concluded to give a corre- will send $2 within 7 days and $2 each month until spondence course aside from our regular day and steel ope foòt or more in length. The I have paid the special price of If is rounded to a I decide not to keep the books, I will notify you at [tight classes. Write for rates. FREE learning bottom edge of the tool once and bold them subject to your order. Title not instruments. semi -circle and the sides taper towards the to pass to me until the set is fully paid for. Write for Literature. SOUTHERN WIRELESS top so as to give the appearance as shown INSTITUTE, 22 St. Paul St., Baltimore, Mary- land. in tool drawing at Fig. 4. The grooves Name in small bearings are cut to semi -circular ADVERTISING PAYS shape from the oil ring slots, so that the Address It pays the man who advertises and it pays the man who answers ads. For advertising rates in the E. E.. address oil as it falls on the shaft from the revolv- Reference Advertising Dept.. 233 Fulton St., N. Y. ing oil rings or oil chains, will be spread You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 954 ELECTRICAL EXPERIMENTER January, 1920

along the shaft by means of these grooves or glands. The position of the oil rings or chains are shown at Fig. 4, and when Is You r Transmitter the shaft is placed in the bearing and slowly turned, the rings should rest on it Really Tuned? and be revolved by it. They dip into the oil in the lower part of the bearing hous- You may think it is but you don't know unless your ing in the manner shown, and keep a con- station is equipped with a reliable Antenna Ammeter. tinuous supply of oil on the shaft. Any These Roller -Smith Hot -Wire Ammeters were made superfluous oil runs out of the ends of the for the U. S. Army Air Service for use on fighting bearings and drops back into the oil well planes. below. At the right of Fig. 4 is shown a more elaborate tree design of grooving in a bab- Regularly $13- Our Special Price, $ 7 bitt bearing from a single oil ring slot. With the Armistice cane a cancellation of contracts and these Ammeters, which These slots are usually cut in the top of had successfully passed the exacting Government tests, were returned to the the bearing, as becomes evident. These manufacturers. Each is in perfect condition, packed in its original carton and grooves are cut in babbitt metal bearings ready for immediate shipment. and sometimes in bronze or other bearings The scale reading is: 0 -2.5 Amperes. Shunt giving double or triple this range, by means of a tool of the shape shown and 75c extra. described, hitting the tool lightly with a hammer and taking pains to keep the By buying the entire surplus we are able to sell these Ammeters at less than groove in of approximately even depth. It the Government paid for them lots of one thousand. Better order one today takes quite a little practise to make a good as they are going fast. Remit by check or money order. job of the grooving but the experience, A. H. GREBE & CO., 70 Van Wyck Blvd., Richmond Hill, N. Y. once gained, is always valuable. (To be continued)

"THERE'S MONEY /N /T'>' Au OscîlH oâá1I. dio Zi= . EARN TELEGRAPHY_M ñ TELEPHONE AND TELEGRAPH -_MORSE AND WIRELESS=_- - (Continued from page 908)

TEACH YOURSELF The latter instrument switches from to half the usual time, at trifling cost, with the the oscillating circuit to the rectifier circuit, wonderful Automatic Transmitter. THE OMNIGRAPH, Sends unlimited Morse or Continental messages. at so that the filaments of the tubes in either any speed, just as an expert operator would. circuit may be adjusted to the proper cur- rent values. Adsptsd by U.S. Oss't. 4 stylus Catalogue treed Receptacles for the four oscillating tubes are located directly below the microphone. OMNIGRAPH MFG. CO. These receptacles take the de Forest VT 391. Cortlandt St. New York Audion bulb which is provided with a four prong base and fits into the receptacle with a bayonet lock. This is a decided ad- vantage since, if a tube burns out it may be instantly replaced without having to BOYS, make connection to binding posts, etc., by means of flexible leads as in the old Our Radio Transformers Are the Goods fashion. On the right -hand side of the panel below the tubes is located the tuning The only drawback they have is the fact that we have condenser and receiver. This post repre- not yet developed a condenser to hold the 1 KW size, sents the aerial receiver connection and the and amateurs who have installed this transformer other side of the receiver is connected directly to the ground. have had trouble, from breaking down their condensers. Near the bottom of the panel on the right We hope soon to announce that a condenser has been and left are mounted the filament rheostats. developed to hold this transformer. One of these controls the filaments of the four oscillating tubes and the other those Send for our new bulletin. of the rectifying tubes at the bottom of the panel. A one ampere scale hot wire THE ACME APPARATUS CO., - CAMBRIDGE, MASS. ammeter is located to the right at the bottom of the panel for reading the high frequency current output in the aerial cir- cuit. This instrument is connected with the Wireless Amateurs, Dealers and Manufacturers! ground lead and there is no danger of a shock should anyone come in contact with Have You Seen the it. At the bottom of the panel is located binding posts for connections with 110 -volt "DEPENDABLE A.C. circuit, a 6 -volt storage battery for the microphone, the key for telegraphing Line of Radio Instruments and Complete Sets ? and the ground connection. Connection to We manufacture a large line of DEPENDABLE apparatus -not the cheap mail the aerial is made by means of a binding order variety, yet our prices are low. Tuners, Couplers, Detectors, Fixed and post mounted to the right of the panel Variable Condensers, Loading Coils, etc., also Binding Posts, Switch Points, Switch at the top. Levers, etc., etc. On the back of the panel is mounted the Send for New Catalog No. 9 helix, (the inductance of which is variable To our New York Office, 19 Park Place, New York City by means of a contact clip), modulation transformer, tuning condensers filament DORON BROS. ELECTRICAL CO. Hamilton, Ohio rheostats, filament switch and condensers, On the base -board in the rear is mounted a special transformer which contains three windings in addition to the input winding LEARN WIRELESS TELEGRAPHY which is connected with the alternating cur- Fascinating and Educational Work -Big Salaries- Prepare Now rent source. One of these windings sup- The United States Shipping Board is making heavy demands upon us for Dodge-trained wireless oper. plies the high potential for the plate circuit ators. Travel all over the world, secure, tree, unsurpassed living accommodations and earn a bigsalary, of the oscillator and the other two the low We Also Teach Morse (Wire) Telegraphy and Railway Accounting potential filament currents. This set is School established 45 years. Endorsed by wireless, railway and telegraph officials. Low rates. Students can earn living expenses while attending school. Catalog Free. Write Today. also supplied to operate on 32 or 110 volts, Dodge's Telegraph and Wireless Indiana direct current supply, a dynamotor being Institute 26th St., Valparaiso, furnished. You benefit by mentioning the "Electrical Exberimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 955

SELENIUM CELLS The Ellectrgcal1 tCllr;flll-ll. eert' THE Work By H. Winfield Secor Construction, Care and Use of (Continued from page 881) Selenium Cells with Special Reference to the Fritts Cell who is invariably a real dyed -in- the -wool By THOMAS W. BENSON engineer- draftsman, has to contend with. The writer has been thru just such work The lack of definite information relative as he now speaks of, and can thus give a to the construction of Selenium Cells has clear idea of how this work runs under Be a Draftsman! led the writer to record the results of general conditions. Of course, it all de- Make $30 to $75 a Week some of his experiments and to fully de- pends on the personnel naturally, and every Your name and address on the coupon brings this great Cyclopedia of Drawing without a penny down. scribe the apparatus as developed by him. person works in a slightly different way. Pay only net shipping charges when books arrive. For instance, one engineer's sketches from With these books and a low price "school set" of draw- CONTENTS OF CHAPTERS ing instruments, obtainable at any store, a man can which you may have to work and prepare become master of drawing and earn $30 to $76 weekly. 1. Selenium The Element your initial LEARN AT HOME -Good paying positions open drawing and layout with the everywhere. Intense activity in manufacturing, 2. Consideration of Cell types and their full details on them which you have gleaned railroading, building, etc., calls for more draftsmen. Characteristics ; The Bildwell Cell; The Ruhmer Cell; The Mercadier Cell; The during several hours study of a dozen Shipped on 7 Days' FREE Trial Bell and Taintor Cell; The Gripenberg catalogs or so and your ever -ready slide - Cell rule and pocket text -book, may be a very CYCLOPEDIA OF DRAWING 3. Construction of Fritts Selenium Cells 4 Volumes. 1650 Pages. Thousands of Illustrations. 4. Testing and Maturing Selenium complete and respectable diagram made Cells Bound in genuine American morocco. Pages 634 x 835 5. Applications of Selenium Cells out on cross -section paper with at least inches. Covers all branches of Drafting- Archi- 6. The Care of Selenium Cells legible figures and letters on them. On tecture, Electrical, Structural Steel Sheet Metal, 73 pages, 15 diagrams and 3 halftone page the other hand, possibly due to the per- etc. Teaches pen -and -ink rendering, lettering, free- plates, 7.A x hand, perspective, shades and shadows, working 5% inches. Cloth. sonal traits of the expert who made these shop drawings, machine design, etc., etc. PRICE $1.50 Only if you keep the sketches, or perhaps due to his being un- 50c a Week books. Couponpo explains der great pressure of work, the engineer - good only within borders of U. S. and Canada. Free Membership In This Society. -A Consulting :UPON & CHAMBERLAIN draftsman may have to work from sketches Membership given tree with each set -worth $12.00. 120 G Liberty Street, New York which are more or less difficult to under- AMERICAN TECHNICAL SOCIETY stand. Dept. 13-251 Chicago Drafting students, and also engineering 'AMERICAN students, but particularly the former, TECHNICAL should therefore study the fundamentals SOCIETY Dept. D. 251 COPPER AERIAL WIRE of engineering calculations and design very 14WS Chicago, U.S.A. thoroly, for they will find that unless Please send Cyclopedia of they intend to remain as draftsmen, they Drawing for 7 days' examina- TWO FEET FOR tion, shipping charges collect. will have to educate themselves so as to I will send $2 within 7 days and $2 a month until $14.80 is paid, or notify be able to grasp the lower rungs of the you and hold books subject to your order. ONE CENT Title not to pass until fully paid. We are offering pure cop- engineering ladder, so to speak. As an ex- ample, the engineer- draftsman may be Name per aerial wire at 50c for called upon to make 100 feet-No. 14 gauge. an initial or prelimi- Address Postage and nary drawing or layout of a new piece of Reference insurance engineering work or apparatus in which charges must accompany all ,....., ele:. -a 'awrz.vv .->fn. crrvn orders or they be he would have to do considerable calcu- will lating in order to properly proportionate shipped by express- collect. No C. O. D. orders accepted. the various parts. He should be thoroly schooled of course in arithmetic, plane and Delivery will be made im- sÿ mediately upon receipt of solid geometry and trigonometry, and he will find it valuable indeed to know some- order. thing A partial list of a few more of our bar- of algebra thru to quadratics. In gains is printed below. the designing of dynamos and motors, elec- Magnets-large and powerful S .30 tromagnets and solenoids, rheostats and % drYY*,Antne4rieeai7loSira"r.:Sg`

is a specially prepared oiled linen, and from which blue prints are later made by pass- MakeThis ing sunlight, or light from an electric arc thru them. The tracing is made with FLASHLIGHT The Key BATTERY regular black drawing ink with the usual To Success - drafting pens and instruments, the tracer The secret of busi- Yourself' ness and social suc- -Then /-You simply having to follow the lines on the cess is the ability Easily in to remember. 1 3MINuT s Know original drawing as laid out by the engi- can FRESH: make your mind an Infallible neer- draftsman, whose drawings are usu- classified index from which you can instantly select thoughts, facts, ally made on some strong quality drawing figures, names, faces. Enables you to concentrate. develop sell control. paper. Tracings are often made of draw- overcome baahfulnaa, think on your Serviceable ings in books or catalogs, photographs, feet, address an audience. Easy. Simple. The result of 20 year.' experience de- maps and innumerable other illustrations veloping memories of tbouoands. "Make -Ur -Own" and drawings met with in the thousand Prof. Write Today fnr free booklet "Hew Henry rlhied Memory Tout. sleds how to obttainm - and one details of engineering work. Dickson, NREE book, "How To Spook to Publio.' Batteries - The young men of today are of course Principal Instructive- Practical -Useful. Every interested in all these things, for in this Dickson School of Memory, 101 Heust Bldg., Chicago, W. boy should have one. A Xmas Gift that great field of engineering, which is ever POPULARITY any friend would more than appreciate. expanding and growing at tremendous strides, the students today will become the J s If you play quaint, dreamy Hawaiian munit Make Flashlight Batteries draftsmen and engineers of tomorrow. or latest songe on the Ukulele you will be pre Fresh wanted everywhere. We teach by mati 20 Generally speaking, a tracer, presuming he lue Do it Yourself and see the mystic charm of Hawaiian Ukulelgivemyou c, everything making your own light. Have fun doing it. So is a young man of possibly sixteen to tree. Ask us to send the story Hawaiian munie. You will love it. simple any child-can make them. twenty years of age, will not remain as No obligation -absolutely free. Outfit comes packed in neat Xmas box. Fully guaranteed a tracer very long. Possibly in six months ne Hawaiian Institute of Music or. your money back. to a year, he may be given a position as 1400 Broadway, Dent ry& New York junior year or Something New - Nothing draftsman, and in another Built for the Owner $108500 ' like it on the market. so he may, if he is a conscientious student Better Light -Lasts and a careful draftsman, be, advanced to Longer the position of a full -fledged draftsman or Simple, Sturdy construction. 400% more flashlight ser- engineer- draftsman. In this connection it Low cost of up -keep vice for less money and may be said that many young college men, and operation. Can- _ your flashlight is always tilever springs In rear. ''i % :" 5 4e 1. -27 H. P. f?. graduates Comfortable E -Z riding - 108 in.wheel base ready when you want, it. of the various engineering immediate deu,.eriea. Fifth eneeaaa. Fits Phan! in. tubular flashlight case. Only courses, first make their acquaintance with Dealers Wanted eel rtor. I ppo. Libere. in dealers' territory. Wonderfulwonderful opportunities.o satisfactory thing to Use around house, car, the commercial world, via the drafting Write er Wire NOWg garage, anywhere. Order one of the following THE SENECA MOTORCAR CO. ,41 Seneca Factory, FOSTORIA, OHIO outfits today : room. It is a very good way in which to learn the rudiments of profession in Serviceable Flashlight Outfit- Flashlight case. heavily their IS THE Melded, mazda lamp, complete with 6 -cell a first -hand way, so that they are familiar "Make -Ur -Own" battery outfit $2q35L . J with all details and work to be done by BIBLE TRUE Renewal Outfit-Parts and Chemicals to Q1 .00 You MUST read the remarkable book that make 6 cells complete $1 each department of a modern engineering has been suppressed over 100 YEARS. Add 15c to cover postage. organization. Sent by Mall prepaid only 50e. Attractive Proposition to Agents. Ir. after you read this sensational master- piece, you do not think it is worth TEN SERVICEABLE BATTERY & SUPPLY CO. BLUE PRINTING TIMES 50c we will refund your money. Exclusive Sales Agents Know the Truth! You will be Startled! Order at once. 30 N. Michigan Ave., Dept. 25, Chicago. III. Truth Pub. Co., Dept. A.E., 1400 B'dw'y, N. Y. Blue prints are not total strangers to any one today as everyone has seen blue prints at some time or other, even if they were HEAD NEU- nothing else than those of their own homes. ACHES There are vartous kinds of prints now in Ai RAL- use, such as black prints and brown prints, F L U G I A but the time -honored blue print still holds WOMEN'S AGF-1ES its own to a very large extent, and millions ASK FOR A-K TABLETS of them are turned out every day, carry- ing with them masses of detail and calcu- SAVE 25% to 60% on slightly used lations which serve as the connecting link GRAFLEX-KODAKS between the engineering staff and the pro- Cameras and Lenses of every description. Equal to new. Save money. write now for ducing or manufacturing staff. The engi- Free Bargain Book and Catalog neer talks with his drawings and the pro- listing undred. of money-saving bargains in lightly used and new cameras and su liieee. All goods sold on 10 days' Free Trio. Money back duction expert and machinist interpret If not satisfied. chances mitt We haveub ens in the Photographic these drawings and construct the machine business over 18 years. Write now. from them. Good drawings are not only CENTRAL CAMERA CO., Dept. 171, 124 S. Wabash, Chicago necessary, but are demanded in the best engineering circles everywhere, and it has been said, and rightly so, that a good draw- Handwriting Tells You Secrets ing or blue print should contain all the Bo successful. Find out what holds you back. necessary views of the machine, and each Send us an ink specimen of your handwriting and $1.00. Our expert Graphologists will tell part thereof as well as all necessary di- you your faults, virtues, talents, etc. Your $1.00 mensions, such that this blue print can be back if you are not satisfied. given to a model maker or machinist, and ROBERT R. ROSS. 110 West 40th St., N. Y. the complete machine constructed accur- ately, without one word of explanation from the designer. Send for a Complete Catalog of EARLE LIEDERMAN The Acme of Physical Perfection The old solar printing frame, which is MASONIC BOOKS A Marvel of Strength pushed out an upper window on rails, with I have found the short cut to physical its glass face turned toward the sun, is Jewelry and Goods perfection and health. I have applied it to still in use in many small drafting depart- my own liödy and have trained many of the REDDING & CO. world's strongest men by this same method. ments all over the world. There has Publishers and Manufacturers I can positively make you A MARVEL OF been a new era in blue printing- thanks Dept. 5 200 Fifth Avenue N. Y. STRENGTH by this most direct short method. to the powerful electric arc light, and blue Send for MY NEW BOOK prints are made today a hundred times "Muscular Development" faster than they ever were before. One E A BANKER It tells the secret. Handsomely illustrated Prepare by mail in spare time for thin attractive probes- of these machines has a vertical glass :tog in which there are erra et opportunkiee for boll, men with 25 full page photographs of myself and women. Send at ce for free book, How to and some of the world's best athletes whom cylinder while another type shown in one Become a Banker," by EDGAR G. Bldg., President, American School of Bunking. I l4MCLene Bldg., Columbus. 0. I have trained. This valuable book and my illustrations, has a special offer will be sent on receipt of 10c, of the accompanying stamps or coin, to cover cost of wrapping horizontal glass cylinder,-the arc is BE AN EXPERT and mailing. Don't delay I Send for it now, turned on and the paper exposed. The while it is on your mind. %C/ light passes readily thru the uninked por- "and- n new ....nd; corrects EARLE E. LIEDERMAN tions of the tracing cloth, but does not your writing in few day's.. Big improvement in three Dept. 216 203 Broadway, New York home. No failures. Complete outline FItEE. pass thru the inked lines and sections. Write C. J. Cement. Dept. 44, St. Louie. Mo. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 957

The blue print paper is then removed from the machine. In the earliest model of the Big. Money for Boys! Rider Aenfs Wanted electric blue printer, the paper had to be w In every neighborhood to ride and removed from the machine and past thru exhibit a sample RANGER bicycle a developing and fixing bath, and then furnished by us. Choice of 44 styles, colore and sizes in the famous Ranger washed. In the later model of the hori- line. Mead Rider Agents make big zontal drum type, the developing is done money in spare time hours -after school or work. right in the machine itself, and the fin- 30 Days Free Trial ished blue prints are reeled out in a con- Is allowed on every RANGER tinuous roll at the other side of the ma- bicycle. We prepay freight charges. If not pleased the chine, in a very short space of time. rial costs you nothing, Factory Rider We sell bicycles-To- made in our own THE TRIUMPH OF THE ENGINEER -THE big factories DIRECT TO THE FINISHED MACHINE RIDER- giving you a superior product at greatly reduced coat. Save time, money and trouble by The happiest day of an engineer's life Learn dealing direct with our great Factory organization Satis- occurs when his first machine or device has faction in every detail guaran- been finished and proven successful under teed or money promptly re- fund, d. test. When the machine, installation or de- ELEC Lampe, Wheels, is finished by the workman then EASY TIRES parts and sup. vice finally Payments plies at half usual prices are also the engineer, and frequently the consulting There is a wonderful opportunity right Nine months fully described and illustrated if is one on the staff, is in- to pay if de- in the big free Ranger Catalog. engineer, there now for boys who like electricity. Boye sired at a SEND NO MONEY, but write vited to witness the test of the apparatus. small advance us today for factory prices, lib- who are ambitious and will train them- over our spe- eral terms and if desired Rider These tests are of the utmost importance, cial cash prices Agents Plan. and in all well -regulated engineering estab- selves in spare time can step into positions CYCLE COMPANY lishments having an engineering depart- just as soon as they are ready. Good sal- M EA D Dept.R.A. -10Z Chicago ment, it is seen to that both the eventual aries are offered to start with splendid customer for the machine, who is to use chances for rapid promotion. Mend Your Pots, Pans and device, as well as the designer, are Toys and do all the Metal Repair- satisfied that everything is right and as it For 28 years the International Correspond- ing with should be. Electrical machinery is tested ence Schools have been training boys for suc- PER by voltmeters, ammeters, watt- meters, and cess in electricity and over 200 other subjects. TUBE in the case of motors and dynamos, the They will help you prepare right at home for TORCH to speed is carefully checked. Frequently, a position in the line of electrical work you like $1.253 during the test by speed indicators or tach- best -or in any other work that appeals to you. ometers; many other electrical and me- Thousands of boys, through I. C. S. training, have stepped into fine jobs, but never were A PASTE chanical qualities are carefully measured 6 THAT TURNS É under the direction of the designer. Sev- opportunities so great as now. INTO METAL large electrical manufacturing a WHEN HEATED eral of the Let the I. C. S. help you. Choose the work you like including the Gen- in the cotipon below, then mark and mail it today. ,' A match will do it. Requires no companies in America, best acid or soldering Iron. or eral Electric and the Westinghouse Elec- This doesn't obligate you in the least, and it will bring repairs wires. metals or. metalwareJoins, you information that will you on a successful Sold by hardware and eleetrieel Companies, operate start stores. or sent by us postpaid. tric and Manufacturing career. This is your chance. Don't let, it slip by. SOLDERALL CO, Dept. 9 ' very elaborate testing laboratories, for their Mark and mail this coupon now. 129 Sussex Ave., Newark, N. J. electrical, steam and other machinery, and tar - .-e-.- -TEAR ou. PEPE r . S1.50 r....., .... here it is that many of our engineers just CORRESPONDENCE SCHOOLS l first practical ex- INTERNATIONAL out of college gain their BOX 6216, SCRANTON. PA. in the commercial application of perience Explain, without obligating me, how I can qualify for the their studies. The work is intensely inter- position, or in the subject. before which I mark X. esting, and if the student takes up this ELECTRICAL ENGINEER CHEMICAL ENGINEER Electrician SALESMANSHIP HAIRÌJODE work, or enters one of the testing engineer- Electric Wiring ADVERTISING MAN ing conducted by these large elec- Electric Lighting Window Trimmer ti I courses, Electric Car Running Show Card Writer DDresses trical companies, and if he has the real Heavy Electric Traction Outdoor Sign Painter the him, then he will Electrical Draftsman RAILROADER making of an engineer in Eleetrie Machine Dedgaer ILLUSTRATOR never regret his experience in this work. Telegraph Expert DESIGNER Keeps it Dressed! experience as a basis, the con- Practical Telephony BUSINESS MANAGEMENT wiry, mussy" unruly From this MECHANICAL ENGINEER Private Secretary Stubborn, engineering aspirant will build Mechanical Draftsman BOOKKEEPER hair becomes silky and beautiful scientious Ship Draftsman Stenographer and Typist Gives it that lovely gloss charac- his future career, and we know of no bet- Machine Shop Practice Cert. Pub. Accountant teristic of the hair of stage and to start from. Toolmaker Traffic Management screen stars of both sexes. Fine ter foundation Gas Engineer Commercial Law for the scalp-a tonic as well as a it should be mentioned that CIVIL ENGINEER GOOD ENGLISH beautifier Favorite of both MEN In closing, Surveying and Mapping STATIONARY ENGINEER and WOMEN. Guaranteed harmless naturally every machine design does not NINE FOICEIVN OR ENG7t CIVIL SERVICE and greaseless. TRIAL BOTTLE. ARCHITECT Railway Mail Clerk postpaid. 50c. Larger size (three fulfill its performance, is was theoretically Arehiteetoral Drd/amas Textile Overseer or Sept, times quantity) $1. Satisfaction or intended and, of course, there are a myriad PLUMBING AND HEATING AGRICULTURR Spanish price refunded. Order TODAY. Sheet Metal Worker Poultry in Freneb of reasons why it may not do so. Perhaps Navigator Automobiles Italian Hasgray Laboratories. Pept 12 Chicago the iron, for instance, used in constructing the core of a magnet, dynamo or motor, is Name engineer who 7-249-+8 not of the quality which the Present designed it originally conceived it to be, and Occupation L.ARN GINEERIMG therefore his calculations are upset in spite Street of himself, no matter how elaborate they and No Expert electrical engineers are being paid fabulous salaries may have been. Here an interesting ex- -thousands needed today. We give you personal and engineering is brought City ![tate thorough training -practical, technical courses 3 months ample of electrical to 2 years under expert engineers In electricity, Steam, to light. The layman might reasonably gas, auto, armature winding, drafting. etc. Extensive la- boratory and shop equipment. Not a trade school. Train- ask at this juncture, how could the elec- ing is condensed-if your time is limited. came to the engineer know how many lines of Finlay Engineering College -only one of its kind in the trical West. Day and night sessions -- enroll anytime. Write for magnetic force per square inch of cross - FREE catalog, a post card will do. in his finished sectional area that the iron I won World's First Prize for best course Under my guidance you can dynamo or magnet is going to carry and in Penmanship. Am placing many of Y FINLAY ENGINEERING COLLEGE become an expert penman. at high ampere -turns students as instructors in commercial colleges 1003 Indiana Ave. Kansas City, Mo. what magnetizing force in If you wish to become a better penman. write salaries. FREE one of m Favorite Pens required to produce this magnetic me. I will send u today. will be and a copy of the Ra neomerian Journal. Write REBUILT ELECTRIC MOTORS strength of field in the grade of iron speci- C. W. Ransom. 511 Eeeex BIdg.,KansasCJty.Mo. General fied to be used. As a matter of fact, every Reproducer" Electric) - All grade of iron varies in its magnetic qual- "The Ellis Music Master Westinghouse made for all phonographs. Pleases the most exacting music Crocker- '`r Motora ities, and the only sure way to ascertain lover. Wheeler what ns, individuality o f gartists'fvoicesrand yinstrumenntéare- Emerson Guaranteed before designing the machine, just produced from records in life like reanimation. It sells on Century performance one may expect of it, is to Its merits. Send loo for booklets E, Hints to Music Wagner For One Year Lovers" and 'Music Masters." Agents wanted. alto. procure samples of the actual iron, or "run ELLIS. P. 0. Box 882. Milwaukee, Wisconsin Motore bought. exchanged and repaired and have a permeability test made J. H. ELECTRICAL SUPPLIES of iron," Wholesale Prices in the electrical testing laboratory. From fi RaiseBel Ian HaresforUs Sockets, wire. tape. loom, fuses. switches. out outs. etc. tests he will then know the magnetiz- Wonderful profits easily made at home. New illustrated catalogue free. Satisfaction guar- these We furnish class A stock and pay you anteed or money refunded. ing force required to produce the desired $7 to $12.50 a pair and express charges. HYRE ELECTRIC CO. magnetic flux in lines per square inch of Intereetintellsetrated earning and contract FREE. 631 S. Dearborn St. Chicago, Iii. United Food & Fur Association cross -section in the iron or steel. 329 W. 48th St., Dept. E. New York You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 958 ELECTRICAL EXPERIMENTER January, 1920 Calibrating Elec- trical Measuring Telephone Men Enstruments By THOMAS W. BENSON Use These a WEEK (Ccontinued from page 900)

"I believe If the result obtained is the same as the my own great ammeter reading the instrument is for most N physical activity is due to my personal use practical purposes accurate. of Nuxated Iron," saya for- FREE The same procedure may be gone thru, mer Health Commissioner Wm. increasing R. Herr, of the City of Chicago. the current value each time till a "From my own experience with Nuxated C CEPT this free offer and maximum of five amperes is reached. Iron I feel it is such a valuable blood and It is not usually body building preparation that it ought to use these great up -to -date feasible to correct the be used in every hospital and prescribed by books on the telephone in instrument itself so a correction chart is every physician in the country." Nuxated A made and hung in a convenient. place. Iron helps to make healthier women and your own home or shop a whole This is laid out as in tronger, sturdier men. Used by more than shown Fig. 3, actual 3,000,000 people annually in this coun- week free. current value being shown O to A, while try alone. Increases the strength We will send you all four volumes O to B shows meter readings. and endurance of weak. mn -down, nervous folks in two weeks' bound in genuine red morocco Thus any meter reading can be instantly time, in many cases. Sat- leather, 1728 pages and 2000 isfaction guaranteed pic- converted to actual current by a glance at or money refundded. tures, without one cent in advance. t all goo the chart. Q.:rugglgts. Cyclopedia of For convenience the temperature of the gas and weight of the solution in the bu- a rette have been disregarded, these factors I N TELEPHONY nearly balancing out at ordinary tempera- AND tures in this type of instrument. Having an accurate ammeter, it becomes TELEGRAPHY an easy matter to check a voltameter. Knowing the relation between the voltage, IIVVARIABLY Everything about the telephone is explained amperage in them in simple and plain language - and resistance, as stated in Ohm's Four- months -for -a- dollar subscribers theory-practice- operation -from the first law, we can arrange the apparatus as renew their orders for experimental line to the modern equipment shown in Fig. 4. and complicated switchboards. Not one A known resistance is detail has been overlooked. Every vital put in the circuit at R ; by passing currents fact that you need to make you an expert of different strengths we can check the THE PHOTO PLAY WORLD is in them. voltameter with the formula : because they find this high class Free Consulting Service publication indispensable for their E library every month. If you wish to keep the books on our easy I terms of $2.00 a month, we will include =- FREE a year's Consulting Membership in R If you are not a regular reader, a the American Technical Society, and you dollar will bring you the next four can have the services of our engineers and A standard resistance can be purchased numbers, each bigger and better experts for one year as often as you wish at a reasonable price and are rather difficult to write in and ask for their help on any to than ever. When your subscription subject within the scope of the books. construct. However, where necessary, a has expired you'll want the Photo standard ohm at 20° C. can be made by Play World regularly. Send the Coupon Now using 98 feet, 8 inches of No. 20 copper Don't send any money. Just mail the wire. It should be The yearly subscription coupon properly filled out and the books remembered that copper is $3.50- will come to you at once by express col- wire changes in resistance with the tem- 35 cents on newsstands. lect. Keep them a whole week and use perature and the above limit should not be them as if they were your own. Send allowed to exceed 20° Sample copy on request. them back to us if you want to, but give C. (68° F.) if results them a trial anyway, and if you keep are to be reasonably accurate. them send us only $2.00. You can send A correction chart can also be made for THE DOWNS PUBLISHING COMPANY the balance of the special $14.80 price the the same way-$2.00 each month. voltameter if necessary in the same Bulletin Building Philadelphia, Pa. ( ;ive yourself a chance to make some real manner as shown for the ammeter, plotting money-right now. Send the coupon be- actual voltage against the meter readings. fore you turn this page. American Technical Society Don't Wear a Truss Dept. T -251 Chicago, U.S.A. BROOKS APPLIANCE, A SmaIla illectiffäer TOT the modern scientific Invention, the wonderful Chcsil£C't;Ilng new discovery that re- St®ra >e lieves rupture will be sent on trial. No ob- Batteries noxious springs or pads. By Elliott A. White Has automatic Air Cushions. Binds and (Continued from page 899) draws the broken parts together as you would a broken limb. No salves. they are likely No lies. Durable, cheap. to slip past each other and Sent on trial to prove it. thus overlap. The joints in each layer are Protected by U. S. pat- covered up by the next layer above, the ents. Catalogue and L- measure blanks mailed shaped pieces being put alternately on free. Send name and ad- opposite sides. This makes a solid mass of dress today. iron in even layers. In Fig. 1 the solid C. E. BROOKS, 203C. State Street, Marshall, Mich If you would rather have one of these sets for free lines across the face of the core indicate examination Instead of the one described above. cross the joints in the top layer, out the name and price in this coupon and indicate the dotted lines your choice here by placing an (X) in front of the the joints in the layer underneath; the set you want. joints in the third layer will again be in Life's Backbone Law, 13 vols., $44.80. [ ] Fire Prevention and Electricity, 8 vols., Insurance, 4 vols., the position shown by the solid lines, and The success o f with the $24.80. $15.80. so on down your life depends Eh ering, thru the core. It will be noted on your [ ] 6 [ ] Automatic volt , 80 6 achine E 9.p0.Work, that the L pieces are not symmetrical, one Health [ Civil Engineering, and ] 9 [ ] Accounting. 4 vole., side being longer than the other. Exerciser vols., $29.80. 81.4.80. The pur- Strength [ ] Steam Engineering. 7 pose of this is to bring the joints out to In a short time of vols., $21.80. t i Carpentry and Con- you can (The only one trawling, 5 v., the ends and its kind.) ( ] Sanitary Heating and $19.80. away from the ends of the Double Ventilating, 4 vols., I ] Telephony and Teleg- coils, where the core is likely to build up If you are bat- $14.80. raphy, 4 vols., $14.80. Your tling with func- AMERICAN TECHNICAL SOCIETY. Dept. T 251, Chicago ragged. Of course symmetrical stampings tional weakness Please send me a set of Telephony and Telegraphy may be used instead, in which case the Strength in any form -if in 4 volumes. express collect. I will send you $2.00 and improve your you want to ac- do 7 days and $2.00 each month until I have paid joints will come at the ends of the window. H E A L T H quire $14.80. If I don't want to keep the books I will return The core is built up with fair alignment them to you in one week. to More Resisting Power and Vim than you Name a thickness of 1 % ", when the centers of over had. Send for my booklet Life's Backbone. which the coils will be full. gives full description of the automatic exerciser-how It Address The cardboard lining works, and what it will do for you. Send for it now. Reference keeps the corners of the iron sheets from PROF. ADRIAN P. SCHMIDT catching in the tape as they are pushed 1951 Brloá , N.Y You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 959

thru. As many pieces as possible should be forced in. The core should then be squeezed Make YOURSELF together in a large vise, after which it will Worth While be found that still more can be forced thru. When no more pieces will go in, Don't stay In the class of Noiseless Practice is stood up on end on a "no- good" men who never are Target the transformer anything that Fit your .22 with a Maxim Silencer and get and the core knocked into even able to do no end of fun this winter practicing in your flat surface counts; who are despised or backyard and basement. shape by pounding it sharply but carefully pitied by successful wide - with a hammer on all edges and on the awake people-as miserable, sickly failures in the business bevelled corners. This will close all the of life. You never can amount open joints. To keep the core from hum- to anything, while chronic ILENERETTER MARKSMAN ming under load, thin wedges of hard wood ailments have a grip on you, FREE making your life miserable, It eliminates recoil and all noise of 1%" wide by 2/" long may be driven into into a sickly the report, and steadies your aim. BOOK turning you Direct from Dealer or Factory $5.00. the coils on top of the iron on both top grouch, and utterly unfitting Write for Free Book of Stories. and bottom sides of the transformer (4 you for successful work of any also be kind. Don't fool yourself by MAXIM SILENCER CO. pieces required). The ends may sticking your head in the sand, 89 Homestead Ave., Hartford, Cone. wound tightly with friction tape. like an ostrich, and refusing the com- to look the facts in the face; As the outside dimensions of you won't "get better pretty pleted transformer are about 5" by 5/" soon " -you'll get worse, and by 234", it can be enclosed in a box of go sliding down into the The scrapheap of useless human these inside dimensions. transformer wrecks, unless you LEARN LANGUAGES shown in the photograph is contained in a AT THE cigar box with outside meaw.rements of Up and Build 5V2" by 6%" by 5 ", but would ko . into one Brace BERLITZ SCHOOL still smaller, as there is considerable spare Yourself Up STREET as to depth. In placing it 28 -30 WEST 34th room, especially STRONGFORT There isn't any doubt that you Brooklyn, 218 -230 Livingston Street in the box, the ends of the core should can do It. if you'll Just WILL rest on blocks of wood about %" thick and The Perfect Mao to do it, and go about it the Washington, Boston. Philadelphia, Detroit. Chi- right way. You can get rid of cago. Baltimore, Orange, Havana, Rlo de Janeiro. long enough to fit tightly against the sides the constipation, indigestion. dyspepsia, biliousness, Buenos Aires. Sao Paola. Cordoba, Paris. London, surfaces of the headaches. or other chronic ailments that are destroy- Madrid, Rome. etc., etc. of the box, so that the ing all your chances of success in life; you can break coils just touch the bottom. Other similar away from any habits that are undermining your con- stitution and holding you back; you can strengthen FRENCH, GERMAN, SPANISH, ITALIAN, &c., &c, blocks should be placed on top of the ends your vital organs, build up your muscular system, become well and strong and By the Berlitz Method students learn not the core, and the core clamped tightly sharpen your wits, and to un- of vigorous again-Just as thousands of other sickly, dis- only to read and write, but especially means men already have succeeded in doing. derstand and to speak the foreign language. between the two sets of blocks by couraged work a LESSONS FREE Patent medicines and druggist's dope didn't TRIAL of bolts or screws. Screws or nails may cure for them and won't for you. Pills and potions outside into the ends will and into the then be put from the their D omoos Take the Right of the blocks to secure the transformer in to tht Build Your Own PHONOGRAPH place. It should then be wholly silent. Let Nature Help You Do It It's Easy With Our Help The five leads are soldered to binding posts SAVE out Natures ways A few hours interesting work top of the box; or the two for the I have spent my lifetime studying saves many dollars and gives on the of restoring lost health strength. energy, manhood, you a machine exactly to suit filament, kept as short as possible, are run to weakened, devitalized, unfortunate men. I have your ideals. We furnish motors, learned the secret of the wonderfully recuperative, re- tone arms, case material, blue thru holes drilled in the top and then to juvenating power she exerts, when a few of her simple prints and full instructions. of the tube socket laws are known, observed and followed. It is the force Playa any record. You can make the terminal screws on which every surgeon and medical man depends in fine profit building phonographs which is screwed to the top also, the other the treatment of his most difficult cases. It never fails, for your friends. when conditions enable it to be efficaciously applied. Write Today for Our Free three leads being connected to binding posts Blue Print Offer. Agents as shown in the wiring diagram, Fig. 3. wanted for OUT ready built Strongfortism Choral eons. The leads from the 110 -volt winding go Strongfortism is the system of living life in Nature's posts (1 and 2, Fig. 3) and way -as it was meant to be lived -and of getting the Choraleon Phonograph Co. to two binding greatest enjoyment out of it. It is the system which 107 Monger Big., Elkhart, Ind thence to a cord and plug, or thru a fused has restored vigorous health, strength and energy to thousands of my pupils. many of whom had given up switch, to a lamp socket or feed wires. all hope of ever getting back the manhood they had end of the 15 -volt winding goes to a lost. What Strongfortism has done for them it can and One will do for YOU. no matter what your present condi- MEN'S SOX marked "positive", to you to it. Give Nature binding post (3) tion or what causes brought of the storage bat- a chance to build you up! Strongfortism will show you BIG SAVING which the positive side how. I GUARANTEE) that Strongfortism will improve $ 35 tery is connected for charging. The other you 100 per cent, if you will follow my directions for 2 Doz Offer good this month only; ex- a few months. ceptional value; excellent for long end of the 15 -volt winding and both ends service ; strong toe and heel; medium weight for year 'round wear; seam - of the 2 -volt winding go to the socket and Send For My FreeBook eas; $2.35 for full box. filament (an ordinary porcelain receptacle Write You will find "Promotion and Conservation of SEND NO MONEY Sox wi; d be is used, as the Tungar tube has a standard Health, Strength and Mental Energy" the most in- sent postage paid. Pay only $2.35 on Edison base). The negative side of the teresting book you ever read. It will tell you all arrival -no more. Money back at once about Strongfortism; how YOtI can build yourself if not satisfied. The risk Is ours. Colors. storage battery goes to a binding post (4) up, Just as my' other pupils have done and are doing black, white, brown. ", and thence to the anode in all parts of the world, make a MAN of yourself. Be sure to state size and color. marked "negative with red blood, pep and energy that will give you a of the tube, to which it is fastened by fair chance to make a big success of whatever you KENNETH HOSIERY MILLS undertake. No patent medicines to buy; no com- Dept. 7, 915 E. 54th St. Chicaeo means of a Fahnestock or Eureka spring plicated, expensive apparatus required; you can prac- projecting from the tice Strongfortism and get all the benefit of it in the EASIEST SHORTHAND clip on the single wire privacy of your own bedroom, if you like, without in Learnin S evenings homestud[. top of the tube. Care should be taken not any way interfering with your present occupation. then scuuire speed with K. Iì Don't put off sending for the book-IT'S FREE. Shorthand. to handle this wire roughly, as the seal Write today. Fill out the coupon below and enclose vee b eap sImeW ea dicatipnp, epéetc. where the wire comes thru three 2c stamps for packing and postage, and I will is easily broken mail you a copy at once, together with a special letter pleasa t practice.etie. Favorite rie glass, in which case the tube becomes on the points in which you are particularly interested. d for personal use; make notes the at lectures meetings;gs; keep n- useless. fld diaBbti Ip my pr ofalrg avy, d the 2 -volt Four career. n A cooks, com- In operation the current from LIONEL STRONGFORT mercial schools; y public and private ter. fila- ben, teachers. Sticht coat. N. 1. Shorthand winding of the transformer keeps the Physical and Health Specialist -for beee le, Including YOU. Proof Ireeeps, from the 15- GuaranteeandpBrochure witbTeetlmeainia ree,poetpdd.Addreee: ment incandescent. Current 1136 Strongfort Institute, Newark, N. J. KING INSTITUTE, EI- 300StatIon F, NEW YORK CITY volt winding passes thru the battery and then thru the tube, from the anode back to CUT OUT AND MAIL THIS COUPON Who wants these the filament, thru the ionized gas. The lllr. Lionel Strongfort, Newark, N. 7. ? Tungar tube is a rectifier or check-valve Dear Strongfort:- Please send me your book, "Pro- Boxing Lessons to pass in only the motion and Conservation of Health, Strength and We guarantee we can teach you Boxing and which allows current Mental Energy," for postage of which I enclose three one The alternating current is 2c stamps to cover mailing expenses. I have marked Self Defense by mail. We will send complete direction. (X) before the subject in which I am interested. course on approval. You can return it or pay thus rectified into pulsating direct current (11381 $5 ,in 5 days. Ask for it today. for charging the battery, as only one -half ..Colds ..Deformity ..Nervousness MARSHALL STILLMAN ASSOCIATION This sin- ..Catarrh ..Insomnia ..Poor Memory 461 Fourth Ave., N. Y. of each wave is allowed to pass. .. Asthma ..Heartweakneas ..Rheumatism Suite E -1 No. as a "half- wave" ..Obesity ..Short Wind ..Poor Circulation gle tube outfit is known ..Headache ..Flat Feet ..Skin Disorders rectifier. Figure 4 shows how a "full ..Thinness ..Conatipatton ..Despondency ..Rupture ..Biliousness ..Round Shoulders wave" rectifier may be made with two ..Neuritis ..Torpid Liver ..Lung Troubles MUSIC TAUGHT FREE of charging ..Neuralgia ..Indigestion ..Increased Height tubes, furnishing 4 amperes ..Flat Chest aNIMM.aaI...1aaalaaaa -.=MIME a This rectifies both halves of the a a IVn1. Irameema asa current. ..46.7.SM Msltf'i saAOMaaaOOa to two 2 -volt and two 15- Name 'a wave, but requires Write plainly Boa can aa Tntaci., like fit quidlly instead of one of each; tho In Your Home. Write today for our booklet. It tells volt windings Ago Occupation how to learn to play Piano, Organ, Violin. Mandolin. with no appreciable increase in the size of Guitar, Banjo. etc. Beginners or advanced pupils. coils, and the same dimen- Street of Music.57 Lakeside Chicago the transformer American School Bldg., sions can be used. In this case the rectifier City State to advertisers. You benefit by mentioning the "Electrical Experimenter" when writing 960 ELECTRICAL EXPERIMENTER January, 1920

Mechanical terminals are connected to two bindin The little matter of r 1, in stamps oral... wit posts, to which the is Theg you the Pathfinder weeks on trl he battery also connecte Pathfinder is an illustrated weekly, published at the with the polarity indicated by the signs a ' What Nations center. for the Nation; a paper that prints shown in the figure. all the the worldno In 2sthe truth Engineering and a new a truth; En Its 27th year. This paper fills the bill without emptying When the tube is operating a blue glo W 15 Cents the purse; it costs but Si a year. If you want will be seen in e to keep posted the space between th Will bring oa what is going oa Washington has become anode cone and the filament and also be - 'n the world. at the least the World's Capital and expense of time or money, reading the tween the filament e Pathfinder is supporting wires insid this is your means. If like silting In the inner the tube. Under normal operating condi ou want a paper In your council with those who home hick is stia- mold the world's destiny. tions this glow soon spreads and fills the From thethe core, reliablq sate[ bulb with a pink glow, e taining, wholesome, the Pathfinder is yours. particularly in th If you would appreciate a paper which puts space above the anode. Considerable hen t everything clearly, briefly -here It is. Send Nations are to show that you might like such a is developed, and for this reason the tube and we will send the Pathfinder on should not be mounted inside probation 13 weeks. The ?no es not repay the box. The is but we are glad to invest tube will not safely carry more 2 paper, new friends. than am- C THE PATHFINDER, Boz 576, Wuklvgtoe D. C peres. This may be determined with a di- rect ICLEARTONE PHONOGRAPHS current ammeter in the battery leads, $4.00 to $200.00 Retail ...new or, after some experience, can be judged Needles 45c per thousand in lots of 500,000 Motors $1.35 to $14.75 each. Tone Arms and DIIIl Ill with fair accuracy by the behavior of the Reproducers $1.30 to $5.75 per set. Main r tube itself. Since the life of Springs 20c to 90e each. Records, Needles. the Tungar Sapphire Points and Parts at reasonable rectifier depends on the brightness of the prices. Learn at Home! filament, the latter should not receive Write for our 54 page catalogue, the only one more of Its kind. in America. illustrating 33 differ- ent styles Employers everywhere are looking for than the voltage specified. Too low a fila- of Talking Machines and over 500 ç ment current will prevent different Phonographic Parts. men with mechanical ability. Splendid sal- rectification. LUCKY 13 PHONOGRAPH COMPANY and rapid Rectification will also be absent with too Export Dept. 98B E. 12th St.. N. Y.. U.S.A. aries advancement are offered. low a charging voltage. If the blue glow There is an easy, delightful way in fails to appear or is too faint, or the charg- which you can learn right at home in ing current is less than 2 amperes, the in- r spare time. For 28 years the Interna- ner end of the 15 -volt winding should be \ tried on the other terminal of the filament, tional Correspondence Schools have been I giving that is, connected to the other terminal men and women just the training screw of the socket. Failure of rectifica- Swin 4 ín..11 fn.between centers, 17 In. total length. Shipptn . w.eight 131bs. Bed they need for success in mechanical engi- tion will then mean increasing the number of lathe is machined. Workmanship Stat- eless. Equipped with wood turning chuck, neering and more than 200 other subjects. of turns on the charging winding, or on Can be fitted with 8 In. fare plate and drill ehpek a. special equipment. Order one today. Price i6.00 cash Hundreds of thousands have stepped into the filament winding, if one of these is at . MFG. CO.. OEM TOLEDO, OHIO good positions through I. C. S. help, but fault, or on the power winding if the volt- :al. STPRER C never were opportunities so great age of both the others is too low. as now. ¿e BUS' nes Let I. Again, in case the current in the tube is Learn ald the C. S. help you. Choose the work you 1 n O Blgoarid- tia- like best in the excessive, a resistance may be inserted be- coupon below, then mark and mail OR'S, -dncre g demand for It today. This doesn't obligate you in the least tween binding post 4 and the anode - mennvelo creative ideas. Oar and it will bring you Information that will start either an adjustable battery rheostat with Sir tty. Work intensely interesting. you on a successful career. This is your chance. a carrying capacity of 2 amperes, or a fixt EARN $25. TO 75. WEEKLY Don't let it slip by. Mark and mail this coupon now. resistance of nickel silver or alloy resist- Tarywherae.ItOur courseacovers eveerypphase o TCAR OUT HERE work completely and thoroughly. Our graduates - - 1 commandd big salaries. Write for catalog. samples ance wire wound in notches around a small and Free Outfit Offer. INTERNATIONAL 681 S. L. Bldg. Detroit. Minh. CORRESPONDENCE SCHOOLS fiber or Bakelite card (see photograph). DETROIT SCHOOL OF LETTERND. a h,, BOX 6217, SCRANTON. PA. Usually an ohm is enough to cut the cur- COPY THIS SKETCH Explain, without obligating me, how I can qualify for the rent down to a proper value. Or a few and let me see what you can do with It. position, or in the subject, before which I mark X. Many spaper artists earning $30.00 ''' \AA turns may be removed from to S126.Ó0or more per week were trained ELECTRICAL ENGINEER CnsinceL ENGINEER one or more by my course of personal indi=idual les- Electrician SALESMANSHIP of the windings, from the charging, power, PICTURE make ---". Electric Wiring ADVERTISING ooriginal giadri drawing to FÌ ean.r S MAN or filament windings, in sketch of Uncle Sam with 6c In stamps for _ Electric Lighting Window Trimmer the order given. sample Picture Chart, list of successful Electric Car Running Show Card Writer However, if the transformer is constructed students, ples of their work and 7 J Heavy Electric Traction Outdoor Sign Painter evidence of what YOU can accomplish. Electrical Draftsmen RAILROADER as here described, and the supply voltage Please state pour age Eleetrla Machine Designer ILLUSTRATOR is 110, no resistance (and consequent of cartooning Telegraph Expert DESIGNER waste The Landon School and Illustrating Practical Telephony BUSINESS MANAGEMENT of energy in heat) is required. `/, 4( MECHANICAL ENGINEER Private Secretary The re- 1510 Schofield Bldg., Cleveland, Ohio Mechanical Draftsman BOOKKEEPER sistance card shown in the photograph is Ship Draftsman Stenographer and Typist Machine Shop Practice Cert. Pub. Accountant not used. The extra binding posts which Toolmaker Traffic Management appear in the photograph Gas Engineer Commercial Law are the terminals [Ç4 LearnVaudevilleActin CIVIL ENGINEER GOOD ENGLISH of extra windings added during construc- Surveying and Mapping STATIONARY ENGINEER Stage Work and Cabaret Entertaining vseeeesfsly MINE POREH'N OR ENG`It CIVIL SERVICE tion so that other tubes might be added to taught by mail. Your opportunity to enter fascina- ARCHITECT Railway Mail Clerk give full wave rectification with greater ting, money- making profession - to travel - see the Arehiteetnr.l Draftsman Textile Overseer or Supt. world-a° vaudeville actor or actress. My simple, PLUMBING AND HEATING AGRICULTURE Spanish current carrying capacity, and also to fur- easy, Complete Professional CourseinS one of Sheet Metal Worker PonitryRalaing French "ta kind- COVEN ALL BBANC H ES. Develops Navigator Automobiles Italian nish various voltages for other purposes, Personality, Confidence, Skill and tells you lust how to get on the Stage. Send 6c postage for illus- such as the operation of vacuum tubes for trated booklet "All About Vaudeville." State age and occupation. Name radio, as described by the author in the Frederic LaDelle, Sta.271, Jackson,Mich. July, 1919, issue of this magazine. Present occupano The rectifier, if built as directed, con- SPECIAL KON -VFR -TER SLIDE RULE The Hamilton HON - VER -TER sumes about the same power as an ordinary j ss..,:, - - elide graduations Street 1 =111/ ` and and No ./\\ over 1800 Charactersr° ll lamp, 50 watts -losses 20, filament 20, jV=V x ,tt115 \\ handle anything in Arithmetic, Also- charging 10 or more. Altho the efficiency .!.4. it +fir4 \pA bra" Geometry or Trig This °tide rule City State " ' = much simplerltoperalte than other. o is therefore not very high -about 20 % C= . EEtli'll.. Ij ; similar lines. Doe°not require awiz- -at and to use It. the same time the convenience of charging t '..- : Eventually You w01 get this rule, a battery where it stands by merely plug- ging into the commercial power circuit, ¶jy $8.60 Instructions free. Leatherette . r" ca ae bee extra. INDEX more than makes up for its lack of effi- _-sue%' J. C. HAMILTON 4 CO. TO 7 St., -'-- Dept. B Water Boston, ciency. After charging it is sufficient to -' Ú.S.0. ELECTRICAL EXPERIMENTER disconnect both sides of the power wind- SCIENCE & INVENTION ing from the 110 -volt supply, for except when the filament is lighted the Tungar DIAMONDS FOR VOLUME 1, 2, 3, 4, 5 tube forms an open circuit and the rectifier may be left permanently connected to the ON CREDIT This index contains 24 pages and Write for Free Catalog. Over 2 "000 illustrations of Dia- shows every 1 monds, Watches. Jewelry. Select any article desired, have article of interest that has been published since storage battery. To start charging, con- it sent to you prepaid. If satisfactory., send us one -fifth of the the inception of the magazine up to and includ- nect the 110 -volt side of the transformer urchase price and keep it. balance in eight equal monthly amounts. ing April, 1918. to the supply circuit. At ordinary rates National Credit Jewelers Write Today. It is absolutely indispensable LO Dept. H22 IOR N. Stets St. Stores In to everybody in- r IS Le.dbtsclyes terested in any kind of electrical research work. for power, a 6-volt 40- ampere -hour battery BROS &C0.Mil CHICAGO, ILL. With it everything of importance in the ad- may be fully charged for about 10c for vancement of electrical science during the last current, a 60-hour for about 13c. To this ' I r°o MOVING PICTURE BUSINESS five years can be readily found. should be added depreciation of the tube, which may be given roughly as 5c per - Small Capital Starts You Price Postpaid charge, up, depending on filament tempera- Our on our easy payment plan. Begin 15e ture and rectified current. The total cost now and get your share. We sell FCatalogREE. Show everything. Write today. EXPERIMENTER PUBLISHING CO. of operation is therefore approximately 15e and 20e you how to earn Atlas Moving Picture Co. Book Dept. 231 Fulton St., N.Y. per charge. i2tj°=rot Ow erde Ost. an sun a- n...e.".. a. cci....-

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 961

Es TheTcfn a 5ub® EIlecta-mn ? By Rogers D. Rusk, M.A. (Continued from page 894) TABLE I Early values of charge of electron. Thomson e =6.5 x10-10 x10-10 AUTO EXPERT Wilson e =3.1 $45 to $75 a week Townsend e =2.4 x10-1° Later values. Learn Auto Engineering Regener ....e=4.79 x10-10 The marvelous development of the automobile industry Rutherford and Geiger e =4.65 x10-10 during recent years has created extraordinary oppor- tunities for men who will specialize in this work. The Millikan e= 4.744x10-1° future is unlimited, with good pay from the start. II Guaranteed Home Training TABLE The American School home study course prepares stu- Prof. Millikan's dents for Consulting or Designing auto work, or Super- Remarkable Agreement of Multiple intendent of an auto manufacturing lant. A shorter course for auto operation and repair for chauffeurs and Charges. garagemen. Send for Free Bulletin and guarantee. No. Calculated Observed American School of Correspondence. Dept.A -261 Chicago 4x4.917 19.66 19.66 Be a Doctor of 5x - 24.59 24.60 PROTECT GOOD TOOLS= 6x 29.50 29.62 - 34.47 ' 7x 34.42 KeepKee p them safe from - Chiropractic knocks, bangs, rust- 8x - 39.34 39.38 Build a successful career in this great profes- Yet bandy and all to- =i sion- Chiropractic the advanced science of treat- gether. The New Util- ing disease through spinal adjustment. The de- ity Chest illustrated is mand for Chiropractors is constantly increasing. 'or garage and home In larger numbers than ever before intelligent, Ise, f o r machinists, 5cgeit ce in Latest thinking people are becoming convinced that it is ool makers, masons, the common sense and really scientific way to re- Jarpenters, repairmen, Movies lieve pain and disease. etc. * We teach you by mail or in class 19 Styles and Sizes (Continued from page 884) 1+6am Instruction under the personal direction of a faculty of compe- Write for Catalog. At Home tent. practical Chiropractors. Prices and name of You can master this good paying profession and nearest dealer. Ask of course, foreign Secret Service agents graduate with the degree of Doctor of Chiroprac- about "Satisfaction try to battle with the wits and brawn of tic while holding your present position. No special or Money - Back" preliminary etudy and no more than a common Guarantee. If no the American Secret Service agents and school education are required. The cost is small dealer near you, write easy. for special offer. the heirs to the property. The scene at -terms UNION TOOL the left shows episode 4 of this mystery. Its CHEST CO., Inc. story consists of the battle of wits, muscles $3000 to $5000 aYear 26 Mill Street mechanisms. The "still," here repro- The success of many Chiropractors has come so Rochester, N. Y. and quickly as to be almost startling. Incomes of duced shows the hero of this photoplay in a from $3000 to $5000 are not rare-some,rare -some upwards he is being slowly of $10,000 a year. Dr. M. D. Moore, of torture machine in which reports $9000 ayear; Dr. L. H. Roche New Jersey, punctured by the iron spikes, which are $5000; Dr. Hanna of Florida, over $5000 You will the same kind of instruction which these gradually being closed upon him. Electric receiveChiropractors received. Your propects will be as Star Storage Batteries amount of pressure bright as theirs. There is no reason why you lights indicate the should not do as well or better. More Dependable being applied which is readily regulated Abed and printed a button. FREELithin co ors. Actual value, Lower in Price by push $31.60 Onthisoffer you get In the lower left picture is depicted a Charts them all free. Send coupon 2 for facts about this free offer- also72- The BEST Guarantee foreign agent in the act of demonstrating page Free Book which tells all about Chiropractic big Liberal discounts to dealers ; write for a machine which will destroy by its terrific and its wonderful possibilities. This is your opportunity to enter a dignified profession, be particulars. discharge the American agent. An im- your own boss, be occupied in pleasant, profitable THE mense Oudin transformer is used, excited t work and become independent. Mail coupon today. by a large transformer having a rotary gap AMERICAN UNIVERSITY CO. it. n STAR STORAGE BATTERY of ponderous proportions connected to Bldg., Dept. 682 Chicago, Ill. I Manufacturers of IManierreWithout cost or obligation send me by mail, Iyour new iC tstrated 72-page book and your Free I Automobile Starting and The Struc4ur ®ff' Charts Offer, Lighting Batteries EIlecelrgcIlty I Name I Muncie, Ind. U. S. A. By Dr. Alfred Gradenwinotz I (Continued from page 892) Address Says the Master Mechanic. The Greb Automatic Grip Puller is a One -Man light I I Puller -- Quick - acting, strong and sim- can be derived from the color of the City Statt ple in the extreme. May be locked in given out by each individual particle : Gold any desired position. A. combination of two or three arms. Heavy Duty particles about 8.5 millionth parts of a cell Size capacity 1" to 18 " -Junior size in thus will give out an MIDGET SLIDE RULE capacity 1" to 7 'Two sets of timeter radius THE ". laws will solve any problem in addi- furnished with each size. orange light ; gold particles 14 millionth tion, subtraction, multiplication. your centimeter in radius green, and division and proportion. A Log - Ten Days' Trial áealçr parts of a root jobber does not have them we will send you Log Scale gives any or power one. Try tan dose. not eatlr money. mercury particles 34 millionth of a centi- of any quantity. Gives Logarithms. return to us and a u. fund your money. light. figures Sines, Tangents, Cosines, Cotan- We also make the GREB RIM Tht)1.. meter in radius, blue The gents and the decimal equivalents THE GRES CO., 230 Stale Street, BOSTON found by these two methods respectively of fractions to six figures. It is grease and water proof and will show a surprising agreement. There is, give years of service. This rule is however, a third method by means of the not to be compared with the paper utility rules which sell for $1.00 Handy Brownian movements just referred to. and are put together with paper measured fasteners. It is accurate. simple The individual figures thus to operate and comparison shows that it is undoubtedly the Binder show that charges as small as one hun- fastest and most complete mie made. Our refund guaran- dredth part of the would -be minimum tee protects you from toes or dieatplppolntment. An instruction book 16 Made Intyre modula sÑaai °white eostedueteet), 51007 White CÌ- For the the electron lutoid 1.25. Leather Casa 50e antra. Send for catalogue of charge can exist, thus proving back Electrical theory either to be unable to represent %6yß err not eaijene' Gilson Slide Rule Co, Niles, Mich. Experimenter actual facts or to require a thorough trans- formation. A STEFFEY MOTOR Holds and pre- Another most interesting phenomenon serves 12 is- on your wheel will con- sues, each of brought out by Prof. Ehrenhaft's investi- vert it into a practical and which can be gations is the fact that these minute par- high grade inserted or re- ticles are carried along by an intense beam successful moved at will, beam motorcycle t hat will without tools. of light either in the direction of the cost you less to operate thau the more Made of heavy or in an opposite direction, according to expensive machines. Write at once and secure lowest fac- material, extra the substance in question. This phenome- tory prices. flxcellent opportunity for agente. Send stamp. reinforced at STEFFEY MFG. CO., Dept. E. 5025 Brown St., Phila. Pa. the back. non, called Photopheresis, strikingly con- firms the admissibility of Svante Arrhenius' daring hypothesis on the transport of KNOW ACCOUNTANCY germs of life along the trajectories of Be a Cost Expert.Earn 53.000 to 510.000 yearly 65c COSTS C.P. A's teach you thoroughly in a few months by our Add postage for 2 lbs. light beams from one celestial body to an- New Home study system -Low Cost -FREE ROOK international Accountants Society. Dept 2626 5.Nid)i5an Ave.Chicagq Experimenter Pub. Co. Inc. Beek Dept. 233 Fultoli St., N.Y. other. 39N You benefit by mentioninv the "Electrical Experimenter" when writing to advertisers. 962 ELECTRICAL EXPERIMENTER January, 1920 Famous Violet Ray Treatment for Health, Vitality and Beauty Now Possible in Your Own Home A new machine has been perfected by scientists which enables anyone to enjoy the benefits of the Violet Ray treatment at home. The tonic effect of Violet Rays upon the system-how they are used to increase health and strength and to overcome specific disorders of the body. FOR many years the wonderful results to be obtained chine is adapted to home use and requires no through the application of elec- special tricity to the body have been known to sci- electrical equipment. The wire which sup- entists. Early investigation and experimen- plies the current simply fits into any electric light tation opened up amazing possibilities for socket and the machine is ready for use. Where the future development of electricity as a curative no current is available, special equipment is fur- agent and a vital source of health. Probably we nished at small extra cost. all recall the first crude contrivance of a storage Now anyone can enjoy all the benefits of the fa- battery in a box from which a mild current of mous Violet Ray treatment. Those who are suf- electricity could be passed through the body. Then fering from some particular ailment will appre- came electric vibrating machines which, however, ciate the wonderful help this handy new instru- simply made use of. the principle of mechanical ment brings to them. And others will be delighted massage and did not apply the action of electricity to avail themselves of its wonderful tonic effects itself to the organs of the body. in creating health and strength, vitalizing the nerves, energizing the cells of the brain and body. The Discovery of Violet Rays Already users of the machine have written en- thusiastic letters to the manufacturers, It was Nikola Tesla, one of the most brilliant telling of modern of the results obtained through it -how it enables scientists, who mystified the world with them to sleep better -how it has soothed the discovery of the peculiar Violet Ray. Tesla nervous their had found a way to troubles-how it has cleared and beauti- convert a current of electricity fied the complexion. And even those who thought into high frequency discharges. This can be de- they were well before scribed in simple terms say that Violet Rays have as the diffusion of a solid brought them an entirely new feeling of health, current into a mist -like discharge. It is similar strength and energy. to a light, invigorating spray of water as compared to the force of a solid stream. One of the most remarkable properties of the Vio- Try the Violet Ray Treatment let Ray is its ability to penetrate solid objects, even including glass which acts as an insulator for Without Cost electricity in its ordinary forms. We are all fa- In order miliar with this phenomenon in the use of the that everyone may know what Violet X -Ray. Rays will do in his or her own particular case, the distributors of this new machine are willing to The Violet Ray Treatment send it to anyone interested for free examina- tion and trial. This liberal offer enables you to It was in the discovery of Violet Rays that the enjoy the delightful sensation of the Violet Ray ideal way was found of applying electricity to the treatment without any body cost or obligation to buy human and obtaining all its wonderful, ben- unless you decide that you want to keep and own eficial effects without any of the dangers that might the machine. It is only necessary to mail the attend its use in its more violent forms. coupon below and you will receive full details of It is just like the refreshing, invigorating effects this special free trial of a shower bath upon the system as compared to offer. the shock of a solid torrent of water. The Violet Ray, as used in the treatment of the Because of its effectivenss in clearing the skin of body, sends a blemishes and beautifying the complexion, the Interesting spray of mild, tiny currents through Violet Ray every part and organ, flowing through each in- machine is used for beauty as well as Book Sent Free finitesimal cell, massaging it, invigorating it and for health. vitalizing it. That is why after a Violet Rap It is impossible to tell treatment one is left with such a delightful feel- in this small space all ing of health and buoyant energy. You have only about the Violet Ray- a suggestion of this feeling in the effects of the What Physicians and what it is and how it ordinary massage. You know how restful and re- Users Say: acts and all the disor- freshing it is-how it brings a glow of health to ders and diseases it is your skin. Trials Friganza, well known actress, says: used to treat success- "Cheerfully will I add my praise for Now imagine this massage applied It's Violetta. fully. But an interest- not only to the the best 'pain chaser' and 'soother' I've had ing surface of the body but to every part, every Or- the goad fortune to find. It's WONDERFUL. book has been pre- gan, every single cell, internal as well as external. It cured my brother of neuritis. As for myself. pared, fully illustrated, No wonder that a Violet Ray treatment makes I use It for facial treatments and general massage. which describes in full one I cannot say too much for It." feel "completely made over' and has such a de- the Violet Ray treat- lightful tonic effect upon the system. It acts upon Dr. Bert H. Rice of Vinton, Iowa, says: "I ment and explains the the brain cells just upon have good results with the Violetta High -Fre- new Violet Ray machine as the other cells of the quency Instrument in all cases of neuralgia. for body, and that is why it is so often used by busi- Almost Instant relief In Facial Neuralgia." home use. It tells ness men to overcome brain fag just how to use the and mental slug- K. L. Allen, D. C 205 Boone National Build- machine gishness. ing, Boone, Iowa, says: "I have had very good to get the same results with the application of High- Frequency results as are obtained Wonderful New Machine Current In cases of Paralysis. Rheumatism and by physicians, drugless This man is using the Now Neuritis and think it Is a great help In drugless healers, sanitariums Violet Ray machine for Brings Violet Ray Treatments healing.)' and beauty specialists. a local trouble -in this Dr. Daniels, Lisbon. North Dakota, says: A copy of this book will case rheumatism. Cloth- to Your Own Home Have used the Violetta In such cases as Goitre. be sent free Bronchitis, Pleurisy. Neuritis. Neuralgia and upon re- ing offers no obstruc- The Violet Ray treatment has long since passed Lumbago, and find ceipt of your request tion to the passage of It very beneficial. In fact. 1 its experimental stage. As its remarkable results would not be without It in my office." on a postal card or the the Violet Rays. were demonstrated, it received the endorsement of coupon below. As the special Ten -Day Trial Offer is made for a limited time only, in order to introduce this de- eminent physicians and scientists. Violet Ray markable machine and to enable you to see for machines became a part of the equipment of hos- yourself just what it is and how it operates, you pitals and sanitariums in the treatment of specific are urged to send for particulars at once. Just diseases and then were adopted by famous beauty write your request on a postal or fill in the coupon specialists because of their effectiveness in elimi- and send it to the manufacturers. There is abso- nating skin diseases and blemishes such as eczema, lutely no cost or obligation in doing this. Address blackheads, pimples, etc., and bringing the glow of healthful color to the complexion. It is almost impossible to list all the various dis- VI -REX ELECTRIC CO., Dept. 41 orders for which Violet Rays are used, for, by restoring normal activity and life to every part 326 West Madison St., Chicago, Ills. of the body, they eliminate the abnormal condi- tions whose presence is generally responsible for any local ailment. For example, as the free cir- culation of blood through the body is established, congestion is removed, eliminating the cause of VI-REX ELECTRIC CO., Dept. 41 headaches, catarrh, nervousness and insomnia. The 326 West Madison St., Chicago, same principle applies to the treatment of neuritis, Ills. rheumatism, lumbago, indigestion and neuralgia. Please send me your free book and particulars Hitherto, however, the costly apparatus necessary of your Ten -Days Free Trial Offer, without any for giving Violet Ray treatments has limited them cost or obligation on my part. only to the well -to -do who could afford the time and money to go to establishments equipped with Name the Violet Ray machine. But now scientists have perfected a new Violet This illustration shows the wonderful new machine Ray machine, Street (or R.F D ) which enables anyone to operating on the same principle, enjoy the remarkable but smaller in size, more convenient to use Violet Ray treatment at home. infinitely and less expensive in cost. This little ma- City State You benefit by mentioning the `Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 963

,111 ,imini,n,,,,.11.,,,,,,,,,11,,,,. rui,,,u ,i , Opportunity Ad -lets read and investigate the offerings OU will find many remarkable opportunities and real bargains in these columns. It will pay you to over the country. No matter what you may be seeking, whether sup- .made every month by reliable firms, dealers and amateurs from all best and most attractive specials plies, automobile accessories, the opportunity to make money, or anything else, you will find listed here the of the month. address must Advertisements in this section nine cents a word for each insertion. No advertisements for less than 75c accepted. Name and accompany all classified advertisements unless placed by an accredited advertising agency. be included at the above rate. Cash should not accepted. Ad- Ten per cent discount for 6 issues, 20 per cent discount for 12 issues. Objectionable or misleading advertisements vertisements for the March issue must reach us not later than February 8. The Circulation of the Experimenter is over 130,000 and climbing every month EXPERIMENTER PUBLISHING CO., INC., 233 Fulton Street, New York, N. Y.

1111..1011$011 ...11111.114:041011.111

Auto Accessories. Business Opportunities. Help Wanted. list. Dissatisfied with your pay, hours or work? Tires- Direct to you prices. Exclusive repre- California Farms for Sale. Write for Perhaps you can get just what you want in the sentatives wanted each locality to use and sell E. R. Waite, Shawnee, Oklahoma. Government Service, which needs immediately Mellinger Extra Ply Tires. Guarantee Bond men women over 18 for all Mel- Amazing Profits manufacturing "Puffed Crisp." thousands of and 8,000 Miles. Sample Sections furnished. at home. Machine, kinds of work. You owe it to yourself to in- linger Tire Company, 980 Oak, Kansas City, Mis- Delicious confection. Begin vestigate. Just send name, address and this souri. instructions complete, $6.50. Samples, toc. "Besco," 3253-EN. Belleplaine Ave., Chicago. number Rl' 2081, for free information and ad- Auto Motors and Supplies. Buick, Hupp, vice. Earl Hopkins, Washington, D. C. Franklin, Michigan, Everett, Hudson, Chalmers. Breed Canaries. Profitable pastime. Particu- Secret Service Operatives and Detectives are Both water and air -cooled motors, $4o.00 each lars free. Bird Farm, Lynnhaven, Virginia. in demand. Earn big money. Travel every- and up. Bosch Magnetos, $i .00 each and up. where. Fascinating work. Learn this profession Head "Quick- Action Advertising -How it is Building Presto Tanks, $5.00. Coils, Carburetors, of by home study. Particulars free. American Lamps, Horns, Air Compressors, Generators, Business for the Progressive Advertisers School of Criminology, Dept. E., Detroit, Mich. Write for bargain bulletin second hand America ": A little story of results, told by Starters. themselves the publisher. Detectives Earn Big Money. Excellent op- auto accessories. Johnston, West End, Pitts- the advertisers -not American burgh, Pa. You will be interested in reading this little book- portunity. Particulars free. Detec- let which we have prepared for prospective ad- tive System, 1968 Broadway, N. Y. Battery Charging Pays Big Profits. City cur- will be gladly mailed Ho- vertisers, a copy of which 2000 Government Railway Mail Clerks Wanted. rent or gas engine operates. Easy terms. to you upon request. It tells you how to talk Men, women, 18 up. $r3oo year to beginners. hart Brothers, Troy, Ohio. business with r,000,000 intelligent, interested and Write immediately for list positions open. Frank - Chain -o'- Spark, the Superplug. Absolutely responsive Americans every month -men who IinInstitute, Dept. N -24 Rochester, N. Y. new principle. Sparks the unsparkable. Fires know what they want and who have the money Detectives make big money. Travel, be your the unfireable. Runs Clean. Automobilist's to buy it. Write for particulars and rates- 225 West 39th own boss. Either sex. We instruct, small cost. delight. Salesman's fortune. Write. Chain -o'- today. Douglas Wakefield Coutlee, Write Johnson's Detective School, 232 Sheldon Spark, 33o Northwestern Building, Minneapolis, St., New York. Ave., rand Rapids, Michigan. Dept. A. Minn. Oklahoma Ranch Farm and Oil Lands. Soo Earn $25 Weekly, spare time, writing for news- Fords Start Easy in Cold Weather. Will run acres Leflore county, Oklahoma. Fine farm and papers, magazines. Experience unnecessary; de- 34 miles per gallon on cheapest gasoline ot half ranch and near gas well that had 26o feet sand. tails free. Press Syndicate, 5665 St. Louis, Mo. kerosene using our 1920 carburetors. Increased $7.50 acre. R. E. Lynch, Tulsa, Okla. Firemen, Brakemen, Baggagemen, $r4o -$2oo; power; styles for all motors; can attach them everywhere. Ex- profits to agents; money back Learn Advertising and make big money. Pre- Colored Portera, by railroads yourself. Big time. perience unnecessary. 897 Ry. Bureau, East St. guarantee; 3o days' trial. Air - Friction Car- pare for this attractive profession in spare Louis, Ills. buretor Company, 27o Madison St., Dayton, Ohio. Complete course only $1.00. R. P. Koehler, i56 W. Vernon, Los Angeles. Wanted- Automobile experts. $5o week. Learn Wanted-Good live selling agents for our easily while earning. Write immediately. testing instruments and publications. Dollars Yearly in Your Back Yard. No gin- garage H. E. Franklin Institute, Dept. N -8o6, Rochester, N. Y. Write for catalogue and particulars. seng, mushroom dope. New ideas. Investigate. mirrors, auto Phillips & Company, Service Division, Union Particulars free. Metz, 313 East 89, New York. Stop Daily Grind, start silvering City, Ind. headlights tableware. Plans free. Clarence Our Guaranteed mail -order plan is a winner. Sprinkle, Dept. 48, Marion, Indiana. No "get- rich - quick" trash; but many have be- Aeronautics. this plan. Full American Made Toys Wanted. An opportunity flyers. i5c brings come independent operating for home -workers on small scale and manufac- 100 Model Aeroplanes. Good particulars 25c. Nothing free. Nowry & Venice, working Drawings and Prices. F. Bruland, Red - turers on large scale. Unlimited quantities 43 St., Boston, Mass. of soldiers, navy, marines. forord, Mich. Washington needed toy army, Money -Talks Magazine. Published for pro- cannons, machine guns, warships and other toys Auctioneers. gressive men. Send for -sample copy. 7o -B and novelties. Greatest chance for industrious Newark, New people for independent business. Enormous de- Auctioneers-Make big money. Free cata- Park Place, Jersey. mand and future in American made toys, all logue. Carpenter's Auction School, Kansas City. Substantial manufacturing corporation wants over United States, Canada, Mexico and South capable men to establish branch and manage America, with over 5o ono to cent stores and Authors -Manuscripts. salesmen; $3oo to $1,500 necessary. You handle toy dealers. This new American industry stands $50 to $150 a Week writing Stories and Photo - own money. Will allow expenses to Baltimore out conspicuously. Factories are established, Plays. Previous Acceptance Not Essential. Dept. if you will qualify. For particulars address people trained, machineries made. Christmas 57 New York Literary Bureau, 14i W. 36th St., Secretary, 416 N. Howard St., Baltimore, Md. sets needed in millions this year. The great New York City. on the hit for 1920 without any competition. We are Would You Like to place your goods buyers of these goods all year, paying fixed Agents Wanted. Philippine Market and from there branch out to prices. Attractive prices offered for painted include the rest ot the Orient? 3,00o islands Agents, 200% profit. Wonderful little article. goods. Experience or tools unnecessary. Hun- with 12,000,000 people Ready, Willing and Able and more made complete per hour. Cast- Something new, sells like wildfire. Carry right goods. All that is needed is that dreds in pocket. Write at once for free sample. to buy your ing form outfits from $3.00 up. If you mean they be told about them. Let us do the telling. business, send for booklet and Information free. Albert Mills, Mgr., 1498 American Bldg., Cincin- it in any language or dialect. We nati, Ohio. We can do Toy Soldier Manufacturing Co.:, 32 Union Square, have a selling organization of 94o trained mu- New York. Signs for store and office windows. $5o week nicipal agents. Advertising by all mediums. easily made. Chicago Sign System, G 326 River Translating, publishing and distributing of cata- Be a Mirror Expert. $3 -$io a day; spare time St., Chicago. logs, circulars and class publications to live home at first; no capital; we train, start you chandeliers, brass beds, prospects. Classified mailing lists. Credit re- making and silvering mirrors French method. $10 Daily refinishing Trade Marks registered. Free prospectus. W. R. Derr, Pres. 579 Decatur automobiles by new method, without capital or ports. Collections, Street Brooklyn. N. Y. experience. Free particulars and proofs. Write Send sample and literature for report. No com- today. Gunmetal Co., Avenue D, Decatur, Ill. peting lines handled. Write on letter head and Instruction. p for valuable booklet on mar- Wonderful Chance. Men's Shirts and Furnish- enclose io cents the craze. Send self- addressed as keting. "The Marketing Man, Inc." Advertis- Crystal Gazing ings at wholesale rates or make $io daily 224 -229 Kneedler Bldg., stamped envelope for free instructions. Zancigs real business. Goodell Co., io4 ing +Selling = Markertink. agent starting P. O. Box 1509, Manila. Studio, Asbury Park, N. J. Duratex Bldg., New York. and Sanita- $10 to $loo Study Bacteriology, Public Health Mexican Diamonds flash like genuine, fool ex- Money-Making Farms -i9 States. tion. Positions pay $ non to $5,000. Interesting perts, stand tests, yet sell for i -5oth the price. acre. Stock tools, crops often included to settle home study course. Degree granted. We help Few live Agents wanted to sell from handsome illustratededatNassau secure positions. Write for prospectus. Ameri- , EC sample case; big profits, pleasant work. Write E icyA. Stroutroutegst Farm Aency can College of Bacteriology, 3003 Stevens Bldg., today. Mexican Diamond Imptg. Co., Box Fi, Street, New York. Chicago. N. Mex. Las Cruces, Make Big Money Opening Safes and Setting Questions Answered, all subjects. Send - for Wonderful Adding Machine. Seven ' columns Combinations. Wayne Strong, Box 143o, Los Circular 7_ Answerall Information Bureau, 5i Retails for $i.00. Sells itself every- Angeles, Cal. York. capacity. Sensa- Cliff St., New where. Most offices purchase several. $6,000 and Lettering in fourteen tional agency proposition. L. J. Leishmen Co., Enter a new business. Earn $3,000 to Cartooning, Comics yearly in professional fees making and fitting a easy lessons. Only $5 postpaid. Over 300 illus- Dept. I, Ogden, Utah. Lesson 25c. Ernie's School, for foot specialty, openings everywhere with all the trations. Sample Make $30 Next Saturday. Speederator trade you can attend to; easily learned by any- Elyria, Ohio. Fords selling like wildfire. Used by Ford Motor few weeks at small expense; Ford run like a Packard. one at home in a Sten -o -Script takes Dictations, Lectures. officials. Makes any no further capital required; no goods to buy; Speeches, 200 -300 words a minute. Wonderful! Stops stalling end bucking. Put on quick, or agency. Address Ste- holes to bore. Sell ten job hunting, soliciting Scientific, Simple. Easily learned in few hours. instant satisfaction. No phenson Laboratory, i8 Back Bay, Boston, Mass. Special Introductory Offer, 58c. Money re- to twelve a day easy. Splendid profits and for a small funded if not satisfactory. 'Sten -o- Script," Ta- exclusive territory. Write quick information. $30 a Week Earnings. I made it with coma, Address Perrin Company, o42 Haywardi Bldg., mail order business. Continued my regular job Wash. tells how. 2c postage. "L. A." $1. Dissatisfied -money back. Long- Detroit, Michigan. daytime. Free booklet educational. office seller; par- Al Exp Scott, Cohoes, N. Y. . hand abbreviated. Time -saving, Agents. Big returns, fast Vrooman Box Reno, Nevada. ticulars and samples free. One Dip Pen Co., 12 Beginners. Complete "Mail Order System." Daily Record Bldg. Baltimore, Md. C, Box too5, Atlantic City, N. J. Moving Picture Plays. and service Wanted-Agents to call on garages dollars weekly work- Earn $1200 a Year in Spare Time writing photo - Best line of testing instrumefts and You can earn over thirty Experience unnecessary. Send for free stations. catalogue. ing spare time for us. H E. Phillips & Com- plays. publications on the market. Complete Service Division, Union City, Ind. book valuable information, special prize offer. H. E. Phillips & Company, Service Division, pany, Photo Playwright College, Box 278 E -9, Chicago. Union City,, Ind. News Correspondents. Photoplays Wanted. Big prices paid. You news- can write then. We show you how. Free par- Novelties. Earn $25 Weekly, spare time, writing for ticulars. Rex Publishers Boxer E -e,- Chicago. papers, magazines. Experience unnecessary; de- 'yy vu Indian Relics, 44 -page catalog free. Grutz- oñ qa0¢ 964) macher, Mukwonago, Wis. tails free. Press Syndicate, 566 St. Louis, Mo. tt.Onttal/P 964 ELECTRICAL EXPERIMENTER January, 1920

( Continued from page 963) Patent Attorneys. Postcards and Pictures. :11ií i, Iustruntent.s. (l Patents Procured-Trade Marks Registered -A, Membership in post card exchange one month, Violins. Deep, Mellow, Soulful comprehensive, experienced, prompt service for three art cards, lists etc., - on credit. the protection and development 25c. Sophie Girard, Easy terms for wonderful instrument. Get de- Preliminary of your ideas. Box 294, Pawtucket, 1. I. tails today. Gustav Henning, 231 rrth St., advice gladly furnished without Miami Florida. charge. Booklet of information and form for dis- Rare Real Photos- Bathing beauties, models, closing idea free on request. Richard B. Owen, the kind you want. Sample Dime. Write. Motor Engines and Dynamos. 13o Owen Bldg., Washington, D. C., or 2278 -T Artiste, Auburn, Ind. Woolworth Bldg., New York. Small Motors and Generators. Cancelled Gov- Make Your Own Phonograph. Particulars free. ernment Contracts. A. C. Motors, $9.5o each Patents- Foremost word free. Write now. DeSelo -PhonE, P. O. Box 720, Attica, Indiana. and up. 52 rio -volt generators, $26.5o each; Metzger, Washington, D. C. Build Your Phonograph. "Perfection" battery -charging outfits, $3o each and up. New John M. high - motors McLachlen, Attorney at Law. Pat- quality spring and electric motors, tone arms, % -rz up to 5 H. P. for all phases and ents, trade marks, copyrights. 410 McLachlen reproducers. Wonderful results. frequencies of current. Write for late Bldg., Washington, Big saving. Bargains bulletin. D. C. New catalog and building instructions mailed in motors and generators. Address M. F. Miller, for ten cents. Indiana Phonograph Supply Motor Sales Dept., No. 12, West End, Ouray Bldg., Washington, D. C., Co., Pa. Pittsburgh Patent Attorney, Mechanical and Electrical Ex- Indianapolisb Ind. pert. Best quality of work and results. Mod- ss Motors, Electric -We buy, sell, exchange mo- erate charges. Advice free. Books. tors of various sizes; large stock; prompt ship- "Inventors' Adviser" sent free on request. ments. General Distributing Co., 22 West First Dear Reader. If Occult, New- Thought and St., Duluth, Minn. Wiliam C. Linton, 918 F St., N. W., Washington, entific books Sci- D. C., 363 University St., Montreal, appeal to you, send for my catalog, ..e...m.ee® Canada. it's free. I have books on Personal Magnetism, Miscellaneous. Patent Attorney, Consulting Engineer. - Concentration, High Spiritualism, Clairvoyance, Seer - Guaranteed -"Titan," "Tufkote" roof paint, class patent service in all its branches. Write ship, Will, Mind, Hypnotism, Mesmerism, Char- heavy bodied, waterproof, fireproof, limited for particulars. M. H. Loughridge, 1457 Broad- acter Readings Healing, Mysticism, Success, period 6oc. gallon, barrels; dustproof "Waxol" way, New York. Salesmanship, Mechanics, Entertainments, etc. wood floor oil $r.00 gallon; wizard leak repair Don't lose your rights to patent protection. A. W. Martens, J -49, Burlington, Iowa. mastic cement $1.00. Martinek Company, 405 Lex- Before disclosing your invention to anyone World -Romic ington send System. Masterkey to all Ian - Avenue, New York. for blank form, "Evidence of Conception," to be guages. Six textbooks, $1.44; Fine signed and French chart, 37c.; beautiful, evergreen, ornamental firs, any witnessed. Form and information Spanish, 37e.; aviation dictionary, $1.5a; French - address, $i.00. Order now. B. B. Lee, Sta. A., concerning patents free. Lancaster and All - English aviation dictionary, 61c. Languages, Vancouver, Wash. wine, 242 Ouray Building, Washington, D. C., 143 W. 47th St., New York. Originators of the form, "Evidence "How to Read Thoughts." Mind Reading at ception." of Con- Crucified Seer Emmerich, Nativity, Egypt and any distance, toc. "How to Hypnotize" -Cure Cana. 4 books, 2oc. Klein Co., Brandon, Minn. Diseases. Give Astounding Exhibitions, $r.00. Patents- Herbert Jenner, patent attorney and Mechanics. "Silent Friend" mechanical expert, 622 F Learn how to read blueprints. -Key to Rapid and Honest St., Washington, D. C. Complete 169-page cloth bound book Wealth, $1.00. "How to Win," 362 pages. I report if patent can he had and its exact cost. with zz8 cess Suc- Send for circular. illustrations mailed for $2.00. You cannot lose; Assured, $2.00. "Health Culture Insures your money refunded if not Vital Strength, 25c.; 5 Dozen satisfied. Educa- Money Makers, Inventions Patented, Trade -Marks Registered, tional Institute, 139 Rowland Bldg., Detroit, Soc. Catalogue gratis. Science Institute, E -1336 Labels, Prints, Publications Copyrighted; Michigan. Morse Ave., Chicago, Ill. prompt service, reasonable fees plain advice; request Nature Laws every The Master Key is the best and detailed information before placing your married and engaged per- most coliven- busi- son should know, Soc. Central Company, 6o1 ient for household use; opens 20 different locks. ness. Jaynes & Jaynes, 802 Kellogg, Washing- Ninth Ave., New York. Sent postpaid on receipt of mc, or complete set ton, D. C. of three 25c. Concordia contains essays, formulas, for Safety Key Holder Free. Sharpe Patents-Prompt, personal, efficient service by Year's plans. Novelty Co., Paterson, N. J. an attorney -at -law, skilled subscription so cents, trial 20 cents. Con- in all branches of cordia Magazine, 9 Water, York, Pennsylvania. Wanted-Small Gasoline and Steam Patent Practice. Over 12 years' actual Engines, experi- World's best book for Auto Small Lathes, Drill Presses and other light ma- ence; full information upon request. B. P. Fish - Mechanics. Covers chinery. Will pay high burne, 33o McGill Bldg., Wash., D. Elementary Electricity. Motor Car Electric cash prices for good C. S stems, material. Johnston, West End, Pittsburgh, Pa. Patents in The Engine and Driving Cars. -Fees' installments. Frank T. Ful- Nearly six hundred diagrams. Prepaid to you Big Mail for a stamp. C. E. Robinson, ler, formerly Lieutenant, Engineers Washing- Port- ton, for $2.50. Order to -day. H. E. Phillips & Co., land, Conn. D. C. Service Division, Union City, Ind. 150 Parodies on Latest Songs, 10c. Charles Patent Your Own Inventions. Save attorney's e1111.010111MIIIIM D nes, Winchester , Ind. fees; we prepare applications, furnish full in- Exchange, structions and give satisfaction. Free informa- For Advertisers. tion. Carl Larsen Co., Park Row Bldg., Wanted. Phones, York New audion, other receiving appa- Money? Jacobus Art Ads make small space City. ratus. A. Walmsley, Star Route, Florence, Ala. pay big dividends. Price $5.00. Write today. Inventors, send sketch of model of your inven- Buy, Sell, Exchange. Wireless and electrical facobus Service, 1073 Sanford Ave., Irvington, tion for opinion concerning patentable nature goods. Murdock, Clapp- Eastham, Thordarson, New Jersey. and exact cost of applying for patent. Book, Brandes, etc. Send loc. stamps for our circulars "Quick- Action Advertising -How it is Building "How to Obtain a Patent," sent free. Gives in- listing new standard apparatus at less than Business for the formation on patent procedure and manufacturer's prices. Progressive Advertisers of every inventor tells what We have to exchange: America": A little story of results, told by- the should know. Established twenty - Wireless, Electrical, Optical, Cameras, Printing advertisers themselves -not the publisher. You five years. Chandlee & Chandlee, 414 Seventh Presses, Typewriters. Large list free. LaRoy will be interested in reading this little booklet St., N. W., Washington, D. C. Zehrbach, to College Ave., Hiram, Ohio. which we have prepared for prospective adver- Millions spent annually for ideas! Hundreds For Sale. 5 acres in one Piece. $50 cash or tisers, a copy of which will be gladly mailed now wanted. Patent yours and profit. Write Bond at face value, in Wayne Co., Tenn. About to you upon request. It tells you how to talk today for free books -tell how to protect 2 miles from Waynesboro, business with 1,000,000 your- the county seat. Good intelligent, interested self, how to invent, ideas wanted, how we help cut over land. No improvements. Must sell at and responsive Americans every month -men you sell, etc. 212 Patent Dept., once. First money who know what American In- order or bond gets a War- they want and who have the dustries, Inc., Washin ton, D. C. ranty deed. Will sell to acres for $ioo. P. O. money to buy it. Write for particulars and Box 184, Randolph, Nebraska. rates -today. Douglas Wakefield 225 For Inventors. Coutlee, Sell inch spark coil $1.00. West th St. New York. "Sell New Phones+ 2,000 or Finance Inventions. Read Money - ohm., $3.00. Send stamp for list. Earle Burns, For the Photographer. Talks Magazine. Send for free 93 Union St., Athol, Mass. Park Place, sample copy. 70-B Do you take pictures? Write for free sample Newark, New Jersey. Bicycle, slightly used, fully equipped. Will of our big magazine, showing how to make Inventors -We do experimental Model, Tool, exchange for coin lete wireless outfit. i64 Stone better pictures and earn money. American Pho- Die and Jig Work; Light Manufacturing. Miller Ave., Yonkers, N. Y. toEIZELIL,$bAneP., & O'Brien Mfg. Co., BwildinE.l Saint Paul, Minn. Bargains -$3o Meccano set $r3. $15 Electric Health. "Inventor's Guide" Free on request; gives train $5. Matthew Ehmke, 1936 Howe. St., Chi- valuable advice and information for all invent- cago, Ill. Free -Stop using tobacco. We will give free ors. Write Frank Ledermann, Registered Patent For Sale -i horsepower steam engine $10.00. information how to conquer habit easily and Attorney, 17 Park Row, New York. permanently. Results Guaranteed. Anti -Tobacco Chemical laboratory $lo; other junk. Send for League, Dept. C., Omaha, Nebr. Inventors write me about patents. My fees list. Carroll Fisher, 42 Putnam St., Somer- payable monthly. Booklet free. Frank Fuller, ville, Mass. Pyorrhea (Riggs Disease -Bleeding or Swollen Washington, D. C. Gulps). H. E. Kelty, D. D. S., M. D., pyorrhea For Sale -i',4 H. P. iro -volt, 6o -cycle induction 900 Mechanical Movements, also motor, $30.00; KW. 500 -volt DC. generator, specialist for is years, has developed a success- explaining illustrations I/ ful home treatment for pyorrhea, purifying, 5o Perpetual Motions. My book, $30.00; I hot wire meter,, o -5 amps., $2.00; i hot "Inventor's Universal Educator," fifth edition, wire meter, o -5 amp.; 2 pair woo -ohm healing, preventative. Full month's treatment, tells how phones, $1 postpaid. Or write for free booklet. Pyorem to procure and sell patents. Govern- each $4.00; 2 telephone microphones, each $1.00; ment and motors switches, sockets, rheostats, Mfg. Co y. 439 Seventh St., Brooklyn, N. Y. other costs. Covers the matter from insulators, A to Z. 16o etc. Tobacco or pages elegantly bound. Contains Write for prices at once. J. E. Law, Syca- Snuff Habit Cured or no pay; $1 noted decisions of U. S. Supreme and State more Street, Clarksburg, W. Va. if cured. Remedy sent on trial. Superba Co., Courts on patent SA, Baltimore, Md. cases. Mechanical Movements Sell complete receiving set at bargain. P. greatly assist inventors, suggest new ideas that Leary, 65 Kenwood Park, Springfield, Mass. Too Fat? Reduce weight easily, pleasantly, may prove of great aid in perfecting inventions. no self starvation, no strenuous exercise. Tells how to select an For Sale- Robbins & Myers % -horse motor. Reh- attorney. Has valuable Brand $17. able, guaranteed, Obtain Oil of Korein at any information regarding Patent Sharks, Selling new, George Marx, Le Mars, Iowa. busy pharmacy or write for free brochure to Agents and Brokers. Price $2. Postage free Exchange -3z Winchester auto rifle for wire- Korein Co., NA -3oo, Sta. F., New York. everywhere. Fred G. Dieterich, 603 Ouray Bldg less apparatus. Geran Read, La Grange, Ind. Cigarette, pipe or chewing habit conquered. Washington, D. C. Sell. Loose Coupler, condenser, etc. Quick. Guaranteed. Write for free brochure. Edw. J. Inventions Wanted. Cash or royalty for ideas. Mariel Scharer, Iio West 80th St.. New York. Woods. TB- oo Station F. New York. Adam Fisher Mfg. Co., 2os St. Louis, Mo. Bargain -Telescope, six -inch objective (maker, Office Devices. Clark & Son), six -foot tube, Tripod mounting, Patents for Sale. three Eyepieces. Multigraphs, Addressographs, Write for price. Wm. W. folders, duplica- Wanted- Partner to furnish money to patent Peters, 1107 S. 8th Street, Burlington, Iowa. tors, scalers. bought and sold. Office Device for half Company, 222-W North Wabash, Chicago. interest. Brace Bit cut figures, letters, Wanted -Receiving Set. Prefer Electro Im- etc. W. Farr, Chickasha,sha, Okla. porting Co.'s Sayville or Tuckerton Radio Out- Typewriters. e e w 1 fit. Harry Ritchey, Personal. St. Johns, Ohio. Startling Values in Typewriters $i5 up. Fac- Sell i K. W. 22o -volt primary 6o-cycle Thor - tory rebuilt. All makes. Shipped on trial. Write Write to famous Hawaiian Beauties, Swim- darson Transformer, brand new, $i8. Starrett, today for our Special Offer No. 158 -A. Ribnsaver mers, etc., membership 25c. Hawaiian Corre- 2615 N. Fourth St., Columbus, Ohio. makes pale ribbons like new for one cent. Order spondence Club c/o L. de Roo, Box 306, Honolulu, Hawaii. For Sale -Two Motion Picture Projectors, cost today, soc. postpaid. Whitehead Typewriter Co., $450.00. Will sell cheap. Box 861, Roanoke, Va. M86 NLaSälle St., Chicago, Ill. The Salesman Wins. Thousands of positions M0=11110011111111® open. Sell -15- volume Encyclopedia (nearly new), $ro. Stamps. We teach traveling salesmanship by mail Stamp brings particulars. Fred Higby, 1726 Fair- and guarantee offer of position or Rubber Stamps made refund tuition. view Ave., Boise, Ida. to order. McCaddon For interesting particulars address Kansas enmo,,.eIIM.IMMINI,.IIMIIIINIIIMIRIPe.ROMSMIee.M1111111,e1.111MIe1ee111.111 Company, Zanesville, Ohio. Vo- ® cational Bureau, Miltonvale, Kansas. (Continued on ,a ,e 966) January, 1920 ELECTRICAL EXPERIMENTER 965

This Test Proves That DIRECTOR ö;°rw:'áwTluOF w.sm.n=+,U.t. THE "ALSOP - ALL - SPARK" WAR DEPARTMENT OFFICE OF THE DIRECTOR OF MILITARY AERONAUTICS Saves fuel Does away w,,.,.oo and spark with Chang- Janusry .1, 1919 plugs. ing spark Plugs, Fires d e a d From: Engineering Officer, Camp forrieon, 7a. c a r b o n - Prevents c h o k e d r u n n i n g plugs. engine with Depot. a misfire. To: Oommnndíng Officer, Air Service Causes per- fect c o m - Gives a more bustion. powerful Subject: Supplemental Deport on Test of Alsop Ignition Device. spark. Fortifies any Ignition sys. Eliminates tern. carbon a n d vibration. G u a 1, Di order to asoertaia whether the device would insure ignition rantees from increase of Increases through plugs that were carbonised, creaked or rendered inoperative gasoline speed a n d Other causes, one quart of oil above high level was placed eta unit f9, the oar mileage. power. 's run until the motor died and oould not be again started. The spark -plugs were then inspected and found to be heavily carbonised. What the War Department found to be true about the "Alsop- 2. The Aleop Device was then attached, and within a ehort time All- Spark" is proven every day. Wherever this wonderful little removed and all plugs were firing perfectly. The plug. were immediately device is installed owners enthuse over it. They find it will found to be oleaa - fetus from oil end carbon. cause old, cracked, carbonized, and oil soaked plugs to give was 3. Then the Alsop was removed entirely from the ear,mtor It gas, develops Greece oil etili powerful sparks. eliminates carbon, saves started again and nn for about four hours, thon due to the motor stopped. The heavily power and insures continued driving without misfires. in orani -Oaes, the plugs again became fouled and greater carbonised plugs were examined and replaced without oleanlag. DEALERS- HERE'S YOUR CHANCE reinstalled a. The following day. Jan. 20th, the Alsop device was with same results ae before. There's a constant and growing demand for such a device -one no dangerous, was platted that is absolutely guaranteed -one that has a. later, a mixture of 60% kerosene and 60% gasoline carburettor or ignition device. exposed spark gaps, which may set a car afire, one that does in the tank, no obengee were made in the motor, developed greater poser The engine started se easily es with straight gasoline, not make a car hard to start or cause uneven timing. formations were found on the and continued to operate as above. No oarboa Dealer above mixture. Send $7.50 for 4-cylinder device with money -back guarantee. plugs after using up the tank foil of the discounts and our catalogue of Convincing Government Tests upon request. DEALERS -AGENTS -SALESMEN -WANTED. ALL -SPARK IGNITION CO., Inc. 13 X WATER ST. NEW YORK

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIVIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII! IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIJilillllllllllilllllllllllllllllllllllllllllllllllll! Illllllllllllllllllllillrllllm! I.

YOU CAN LEARN By This Practical Method of Home Study Hundreds of Burgess- trained men and boys have advanced to better positions Instructions on the by means of the practical electrical knowledge easily learned at home by this method. If you are willing to utilize a little of your spare time you can do Electrical Slide Rule the same. A set of concise lessons on the use of the Electri- For Beginners and Experienced Men cal Slide Rule has been This home study course is based upon the years of practical electrical experi- Satisfaction prepared by Mr. Burgess ence of Yorke Burgess who gives personal attention to each student. in response to many re- to what can accomplish with its aid. It is up to you. Assured quests from those who There is no limit you desire to take up the use Results of This Service The Burgess Method is so of this instrument are invariably universally successful that which is invaluable to Practical electricians recommend this course to others. Students we give positive assurance many electrical men. promoted and get better salaries. Over 80 per cent of the students are en- enrollment of perfect satisfaction on A High Grade Slide gaged in the electrical business. Over 15 pen cent of present completing the Rule came through satisfied students. Beginners get employment in electrical work in a leather case and course or money the COMPLETE after taking the course a short while. refunded. There COURSE OF IN- FIFTY -FIFTY are no strings - STRUCTION will be supplied at a VERY This method of learning PRACTICAL ELECTRICITY is supplied on EASY tied to this- REASONABLE COM- PAYMENTS, including apparatus, instruments, material, etc. Start any you are the BINATION PRICE. time -stop any time -your payments cease if you are not satisfied. Send for judge. Write for full infor- without cost or obligation. mation. the BURGESS BOOK to -day. Gives full information YORKE BURGESS, Superintendent BURGESS ELECTRICAL SCHOOL, 745 E. 42nd Street,DEAT Chicago, Ill. BURGESS BLUE BOOK SAND STUDENTSN Price A pocket hand -book for ELECTRICAL MEN and STUDENTS. electrical men all over the country. Used in technical schools. $1.00 Contains over 200 CALCULATION FORMULAS and worked -out Purchased by electrical concerns for employees and customers. problems showing their use. Also DRAWINGS of ELECTRICAL There Is no other book Ilke It. APPARATUS and DEVICES of which the inside connection; are clearly shown. ALTERNATING CURRENT CALCULATIONS A $1.00 bill brings the book. We refund your money If you are and dozens of everyday problems are covered. Recommended by not fully satisfled. BURGESS ENGINEERING CO Consulting Electrical Engineering 750 East Forty- Second Street, Chicago, Illinois

Yon benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 966 ELECTRICAL EXPERIMENTER January, 1920

íC from ruge 964) Learn Dancing. Winter Fishing. Song Poems Wanted. Learn Fox Trot, Waltz, Two -Step and One - Julian's Liquid Fishing Lure. Whole winter's Step in your own home by wonderful Peak supply. One dollar. George Julian, Albany Write the Words for a Song. We write music System of Mail Instruction. Thousands taught Bldg., Boston, Mass. and guarantee publisher's acceptance. Submit successfully. No music needed. Write for free 1111=11111111111=1011111111111111 poems on war, love or any subject. Chester information. William Chandler Peak, M. D., Wanted Music Co., 92o So. Michigan Ave., Room 265, Room 228, 821 Crescent Place, Chicago. to Buy. Chicago, III. Cash for Old False Teeth -We pay up to $35.00 Electrical Supplies and Appliances. per set (broken or not), Also buy discarded Song- writers' Manual and Guide Sent Free 1 Contains valuable instructions and advice. Sub- Battery Charging pays big profits with HB gold, jewelry, gold crowns, bridges, platinum, mit song _poems for examination. We will fur- Equipment. Electric Light and diamonds, watches and silver. Send now. Cash Generators by return mail. Package held 5 to to days for nish music, copyright and facilitate publication Motors can also be furnished on easy payments. sender's approval or sale. Knickerbocker Studios, 319 Gaiety Bldg., Full information free. Hobart Brothers, Troy, of our offer. U. S. Smelting New York. Ohio. Works, Dept. 73, Chicago, Ill. You Write Words for a Song -We write the Lava Insulation is not molded but individually Salesmen Wanted. music, publish and secure a copyright. Submit sawn, lathe turned, milled, drilled, threaded. No poems on any subject. The Metropolitan Studios, limitation on form, only on size. Kilned at two Salesman-Side or main line, to sell low priced 914 So. Michigan Ave:, Room 113, Chicago, Ill. thousand degrees. Hard, strong, accurate, fire, 5,000 -mile guaranteed tires. 3o x 3/ non -skid acid proof. Ask for book. American Lava Insu- sells for $11.95; other sizes in proportion. Good Have you song poems? I have best proposi- lator Company, Chattanooga, Tenn. money -making proposition for live wires. Write, tion. Ray Hibbeler, D -115, 4040 Dickens Ave., Consolidated Tire Coß., 616 So. Michi an Chicago. Chicago. Electrical and general scientific questions answered Free. We desire the privilege of build- Stammering. Write the Words for a Song. We revise poems, ing any special wireless, electrical or scientific write music and guarantee to secure publica- apparatus you may contemplate. Earl Cochran, St- Stu- t- t -tering and Stammering cured at tion. Submit poems on any subject. Broadway Poplar Bluff, Mo. home. Instructive booklet free. Walter McDon- Studios, 197C Fitzgerald Bldg., New York. nell, toy Potomac Bank Bldg.. Electrical Workers and all others who are Washington, D. C. interested in Electrical work in the reconstruc- Song Writers. Stamps and Coins. tion that is taking place to send us their name and receive descriptive literature of Song Writers: You cannot Stamps-45 different packet hinges, 13 different our modern afford to miss blueprint chart method of electrical wiring. Sou- our proposition. Reference, any bank or first - Chile, 1 unused Trinidad -Tobago War Stamp. class 13c. to for 16c. venir information card included. Electrical Wir- sheet music house. Warner C. Williams applicants approvals, others Ref- ing Diagram Box C i73, & Co., Dept. L, Indianapolis, erence. Baumann, 1o33 Levick St., Phila., Pa. Co., Altoona, Pa. Ind. 104 Induction motor connecting diagrams. California gold; quarter size, 27c; half dollar Blueprints in book form. One, two three phase, Short Stories, Manuscripts, Wanted. size, 53c. Columbian nickel and catalogue, toc. $2.70. International Blueprint Co., Box 87, Short Stories, Poems, Mo. Gate- Plays, etc., are wanted Norman Schultz, King City, way,, Kansas City, Missouri. for publication. Literaly Bureau, 165, Hannibal, Stamps -61 All Different Free. Postage, 3c. o. Boys-Here is the simplest and cheapest elec- Essime m m,m,,,,,mm,,,,.x Mention paper. Quaker Stamp Co., Toledo O. tric telegraph ever devised. With the "K" Ap- Scenery For Hire. 1,000 U. S. and Foreign Stamps, including Mexi- plicator you need no batteries. Get electricity can Villa Dollar, all for 25c. C. W. Parker, 77 free, instantly anywhere at any time. Send Collapsible Scenery for all plays. Decorations. Kensington Heights, Meriden, Connecticut. thirty cents (postal money order), for full in- Amelia Grain, Philadelphia. structions how to make the "K" Applicator and 300 Different Stamps, SOc. Fred Anken, 63o 79th how to operate an electric telegraph without Tricks, Puzzles St., Brooklyn, N. Y. batteries. Is easier to make and requires less and Games material than you would use in making a Tricks, Puzzles, Magical Apparatus, Plays, South America. Buy direct. I,000 fine assorted kite. Stage Paraguay, Uruguay, etc., for $z bill. Exchange Gives constant, smooth, even current day and Supplies, Mind -reading Acts, Sensational night, never runs down even upon closed cir- Escapes and Illusions. Free, large illustrated rare stamps with collectors and dealers; lots or 1919 catalogue. on sheets. C. P. Mego, Necochea 193, Lomas cuit. Works on any metallic line, even barbed Oaks Magical Co., Dept. 549, Dezamora; Argentine Republic. wire fence, as no insulators necessary. The "K" Oshkosh, Wis. Applicator, Missouri Valley, Ia. Magic -Card Tricks. Sensational 100 Different Stamps, 12e; zoo, 27c. Michaels, escapes, jokes, Inventors: Models, Dies, Tools, 28 years' novelties. Everything in the amusement line. 5600 Prairie, Chicago. experience, work guaranteed, lowest price. Man- Large illustrated catalogue of a thousand tricks 200 All Different Stamps, including Bosnia, ufacturing of specialties our hobby. Peerless free, Write today. Largest amusement goods Bavaria, China, Guatemala, Bulgaria, Bohemia, Die & Tool Co., tit Opera Pl. D. B., Cincinnati, manufacturers in the world. Heaney Magic Co.,- Polandr Turkey, etc., and Dime Stamp Album, Ohio. Desk zoé, Berlin, Wis. one to all for z5c. Our approval only customer, Radium Lokators guaranteed to shine in the Illusions -Stage tricks with 500 illustrations. sheets contain bargains priced at ic. to 5c. net. Catalogue, and Civil War reve- dark. Attach to electric switches, gas jets, key isc. Small catalogue free. Horn - 15o different U. S. postage holes, etc. t,000 other uses. Send twenty -five mann Magic Company, 304 W. 34th St., New nues for only 75c. Indiana Stamp Co., Dept E., York. Indianapolis, Ind. cents. Agents t00% profit. Radium Products Co., 712 blonroe Place, West New York, New Magic. Entertain at home, Tricks, puzzles, Best one cent approvals in America. F. P. Jersey. novelties. Big Catalogue Iii? So. both St., Phila., Pa. A, 25c: Martinka & Hand, Storage Batteries. Make the plates yourself. Co., Inc. Harry Houdini, President, 493 Sixth Have you seen The Stamp Herald? Finest We will tell you how. Sample plate 4oc. Wind- Avert York Cit monthly stamp paper published. Subscription sor Specialty Co., not incorporated. 5419 Wind- Telegraphy. MINwI.111010111,., 50e. a year. 3 months' trial for 10c. Stamp sor Ave., Chicago, Ill. Herald Publishing Co., Dept. E, Indianapolis, Ind. Telegraphy (both Morse Boys, build your own Electric Motor. Corn - and wireless) and plete Railway Accounting taught thoroughly and outfit $1.75. Blue Prints only 25c. A. F. quickly. Big salaries now Old Coins Wanted. Cassel, 52 W. i3oth St., New York City. paid. Great oppor- tunities. Oldest and Largest School-est. 45 We Buy and Sell Old Coins. $z to $5oo each Blueprints -Motor connections. 236 A. C. Sin- years. Catalogue free. Dodges Institute, 7th paid. Keep All Old Money; you may have valu- gle, two and three phase including voltage, St.. Valparaiso, Ind. able coins, Send roc. for New Illustrated Coin cycle, phase, speed changing. 123 D. C. dia- Value Book, 4 x 6. Guaranteed prices. Get grams. Shows voltage changing, testing, etc. Wireless. osted. Clarke Coin Co., Box 11o, Le Roy, N. Y. 120 Transformer diagrams. Single, two and K. W. transmitting three phase. 17o Rheostats, controllers, com- set and cabinet receiver for sale. Send for photos. O. R. Wimpy, 616 Cameras, Supplies -Photo Developing. pensators, automatic starters and voltage regu- W. Sixth lating devices, with both internal and external St., Marion, Ind. Mail us 15e. with any size film for development connections. to Samples A. C., z5c. Particulars banger -High Voltage. I am selling my sign and six velvet prints. Or send six negatives any free. Charles Chittenden, Dept. A, 3o24 Mat- business complete, Consists of one cut for signs, size and isc. for six prints. Or send 25c. for one thews Avenue, Kansas City, Missouri. one small cut for advertising and 300 signs 7%" 8 x to mounted enlargement. Prompt, perfect x ti/" with envelopes. $25. Leonard Beck, 1298 service. Roanoke Photo Finishing Co., 255 Bell For the Hair Carroll St., Brooklyn, N. Y. Ave., Roanoke, Va. I Was Bald. Obtained hair growth by an In- 10- kilowatt second -hand Clark wireless trans- Amateurs! Send your next roll film and isc. dian's ointment containing genuine bear oil and former, sealed in case, first -class working condi- Will make six prints. Prompt, perfect service. rare plant juices. Many others have had won- tion; operates on no volts alternating current; Greenwood Studio, Woodbury, Vt. derful results. Fine for dandruff. Harmless. gigantic bargain at $55.00; cost $500.00. Sidney, Clean, Neat, Perfect Kodak Finishing at the Will send box, postpaid, with recipe, toc. John S. Friedrich, 350 East Commerce Street, San lowest prices. Work returned the same day re- Hart Brittain, i50 E. 32nd St., BB -3oo, New York. Antonio, Texas. ceived. Send film for sample print and copy of Complete receiving sets $7.00 and up. With moo - catalogue on developing, printing, enlarging and Formulas. ohm receiver, tested minerai, guaranteed. Bulle- hand coloring, also copy of Photo Craft Maga- Whiskey. I will not sell a million formulas for tin for stamp. Jenkins, Room 2, 923 Purchase St., zine, which will help you make better pictures. $1.00. My little book of selected formulas will New Bedford, Mass. Photo Craft Co., Box 69, Ann Arbor, Mich. put you wise. Every formula has been care- While They Last. Heavy current telephone Cameras. Lowest Prices. Supplies and Print- fully selected and plainly printed. Tells you how transmitters with lug ready to mount on your ing at reduced rates. Eliminate the middleman. to make excellent Whiskey or Beer with a good radiophone set. $3.00. Act now. Modern Radio Deal direct with us. Catalog free. Pearl Photo Kick at small cost. A few good formulas are Equipment Co., Elizabeth, N. J. Place, 64o E. Clementine St., Philadelphia, worth a million bad ones. Complete book and the Audion. Its early history and develop- Penna. formulas $1.00 bill. I'm prompt, too. Frank ment, Electron Theory Ward, Fox 5o3, and Trigger Action, com- Baltimore, Md., Dept. D. piled by a Chief Electrician Radio who was sta- Chemicals. Prohibition is here and I have lost my ob. tioned at the Naval Radio School as Instructor My recipes and formulas are yours for One for two years, written by an old amateur for Experimenters, are you interested in novel, Dollar. No still or alcohol required. Just ordi- the amateurs in words that they can understand. chemical experiments? Send toc. for large col- nary kitchen utensils. Lee, 2314 E. Albert, Phila. Also blue print diagrams for hook ups for re- lection. Mere, Sager, 44 Apple St., Tiffin, Ohio. 500 Formulas, including Resilvering Mirrors, ceiving damped signals, using both air exhausted and gas One Hundred Chemical 'Experiments printed in Renewing Dry Batteries, Mechanic Soap, umi- bulbs. Receiving undamped signals and nous Paint, 25c. Ideal Book Shop, 5501-EE North regenerative circuits. Two -step amplifier, using book form, 25e. Oliver R. Stalter, Oshawa, On- same (A) tario, Canada. Robey, Chicago. and (B) batteries for both steps. Wire- 500 less telephony with power bulb. Working blue Chemicals, Chemicals, Chemicals. Regular $,S.00 Successful money- making formulas and prints on how to build trade secrets. Postpaid, 25c. Charles Dynes, a "One to One" trans- chemical outfits $3.5o. Regular $ro.00 chemical Winchester, Indiana. former for use with Audion Amplifier. All for outfits $7.00. For a short time to get ac- $2.00. Address T. O. McKenzie, io4 Warburton quainted. Other prices on application. Eureka 1,000,000 Formulas. Processes. Trade secrets Ave., Yonkers, N. Y. for every business. toi6 Specialty Co., Box 395, Central Station, Toledo, pages, $2. Ideal Book Stranded aerial wire, seven strands of Number Shoo, 5 EE Robe Ohio. North Chicago. 22 pure copper. High tensile strength and t00% Crude Rubber -Experiment with pure uncom- ;ng. n, conductivity. Supply, limited at this price. No Print pounded India Rubber. Make Tire Patching C.O.D.'s. t cent per foot. $9.00 per thousand. Cements, water proof cloth, porous tire filler, 150 Letter Heads, iso Note Heads and aoo En- Lee A. Bates, 8 Moen St., Worcester, Mass. rubber stamps, etc. Pure para grade vlopes, postpaid, $z.00. Commercial Print, (highest Wyoming, Delaware. Switch Points. Binding posts, switch levers, India Rubber. 4 oz., sac.; 8 oz., floc. 1 lb.. $1.25; and small parts; sepd,.ac for catalogue describing 5 lbs.; $S.00. Shipped postpaid. Address Bunsen 3000 Two -Color Labels, $1.25. Irvin J. Wolf, these and other goods. A. W. Bowman & Co., 23 Supply House, 14 S. Canal St., Akron. Ohio. S,,'inn E. Philadelphia. Church St. (Harvard Square). Cambridge, Mass. You ben-nit by mentioning the "Electrical Experimenter" when writing to advertisers. January, 1920 ELECTRICAL EXPERIMENTER 967

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iiaaaiaiiiaí The Demand for Wireless Operators Far Exceeds the Supply The New York Wireless Institute will make you an operator -AT HOME -in your spare time -quickly, easily and thoroughly. No previous training or experience required. Our Home Study Course has been prepared by Radio Experts. Experts able to impart their practical and technical knowledge to YOU in an easy to understand way. The graded lessons mailed you will prove so fascinating that you will be eager for the next one. The instruments furnished free, will make it as easy to learn the Code as it was to learn to talk. All you will have to do, is to listen. Big Salaries Travel the World Over Wireless operators receive excellent salaries rang- A Wireless Operator can visit all parts of the ing from $125 to $200 a month and it is only a world and receive fine pay and maintenance at the positions. There is prac- stepping stone to better Do prefer a steady position with- tically no limit to your earning power. Men who same time. you but yesterday were Wireless Operators are now out travel ? There are many opportunities at the holding positions as Radio Engineers, Radio In- numerous land stations or with the Commercial spectors, Radio Salesmen at salaries up to $5000 Wireless or with the Steamship Companies. a year. FREE Instruments and Text Books We furnish free to all stu- dents, during the course, the wonderful receiving and send- ing set exactly as produced in the ill!rstration. This set is not loaned, but given to all students completing the This wonderful Set for learning the Code furnished free with our Course Course. The Transmitter shown is the celebrated Omnigraph Easy Payments used by several Departments of the U. S. Govern- A small payment down will enroll you. We will make ment and by the leading Universities, Colleges, the payments so easy that anyone ambitious to enter Technical and Telegraph Schools throughout the the fastest growing profession-Wireless -may do so. U. S. and Canada. Start the Omnigraph, place the Send for FREE Booklet phone to your ear and this remarkable invention Without obligating you in any way, send for our book- will send you Wireless Messages, the same as let "How to Become an Expert Wireless Operator" - though you were receiving them, through the air, it is free. Mail the coupon below, or postal or letter- hut do it today. from a Wireless Station hundreds of miles away. When you apply for your license, the U. S. Gov- NEW YORK WIRELESS INSTITUTE ernment will test you with the Omnigraph -the same Dept. 51, 253 Broadway, New York City model Omnigraph as we furnish to our students. 17 aa m m - - on ! i - m O - - m m - - - - = .. a Ask any U. S. Radio Inspector to verify this. New York Wireless Institute Dept. 51, 258 B'way, N. Y. City 1 1 Send me free of charge, your booklet "How to Become an Ex- FREE Post -Graduate Course pert Wireless Operator," containing full particulars of your A one month's Post-Graduate Course, if you so desire, at Course, including your Free Instrument Offer. one of the largest Wireless Schools in N. Y. City. New York -the Wonder City -the largest port in the World 1 Name and the Headquarters of every leading Wireless and Steam- 1 ship Company. 1 Address 1 t City or Town State You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 968 ELECTRICAL EXPERIMENTER January, 1920 ffeakrtÁazzy7Jinz

7eatmii?s, atiktrre A recognized scientific effective means of handling your own case is afforded by the RENULIFE VIOLET RAY HIGH FREQUENCY GENERATOR. It is so designed and made that anyone can apply the wonderful corrective, upbuilding forces of the VIOLET RAY. This pleasant POWERFUL form of electricity has done and is doing wonders in relieving and eliminating pain and suffering. You owe it to yourself to investigate -find out the facts. Get our new booklet explaining the nature of the Violet Ray -its uses, benefits, and applications -send the coupon below at once. WHAT USERS SAY THOUSANDS OF VOLTS "The Renulife Violet Ray High Fr'e- queuey Generator is superior in efficiency No Shock -No Harm -Simply Great Benefits because of its perfect character and con- trol of current, compactness and perfect Current from your light socket is transformed insulation. 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N ..Deaf e.sss and ..Lobarn ..Toothache ..EEa I'iseases AHec. ..Weak Eyes .Nonnes ..Wrinkles ..Enlarged Pros- . .Neorslsis . taw ..Neuritis ffiäesaoa in Name For Address Catarrh, Throat.LunfS -also Ammo,

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers.