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25'M. ELECTRICAL 1 ünP. EXPERIMENTER SCIENCE AND INVENTION

VATCHING PLANTS, GROW SEE PAGE 1246 April, 1920 ELECTRICAL EXPERIMENTER 1225

"Your spare time is your ELECTRICITY capital :" as experts know it VOU do not have tó take time off from work and spend several 1 hundred dollars in tuition in order to master the practical side of electricity. The whole subject is now covered in a low- priced set of books, flexibly -bound and handy pocket -sized. st a few minutes of your spare time spent with the Croft Library of Practical Elec- ,tricity -each day will give you a knowledge which could otherwise be gained only in years of practice. Earn a big salary The salaries of electrical workers are high and constantly going up. And the demand for properly trained men is more insistent than ever before in the history of electricity. NOT ONE CENT Don't be content with $38 to $50 IN ADVANCE per week Merely fill out the coupon below and return to Don't re content with just a fair knowledge of electricity. Don't be us for ten days' absolutely free examination of satisfied with the average electrical worker's salary of $38 to 50 per the CROPT LIBRARY OF PRACTICAL ELEC- week. Know electricity as experts know it. Terrell Croft will tell TRICITY. Use the books in connection with your you how. work for ten full days. See how the hundreds of problems in electrical practice are cleared up in simple language and illustration. If thoroughly convinced The only library of its kind- - that the books will There never enable you to know electricity as has been a set of books or a course on electricity experts know it, send us only $2 in ten days, and 53 that adhered so closely to actual electrical practice. The author, per month for six month. You pay only $20 for a Terrell Croft, procured his knowledge with his sleeves rolled up. com- He was trouble shooter, draftsman, plete electrical education. Return the books at our ex- wireman, central station pense operator -then electrical engineer for the Westinghouse Com- if not entirely pleased. pany, He is a practical man and knòws the exact wants of his fellows workers. He tells of the short cuts to bigger pay, of the why and how of everything in electrical practice today. of

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The Earqh90 IIIIIIIIIIIIIIIIIIIIIIÌIIÌI, 91111111111 IIIN IlrllerIlcar Mullen.? ANY things that we take for granted some- that there is no such tide in the interior of the earth. times turn out to be very much different If there were, the crust of the earth, due to the tidal than we first thought them to be. Take effects of the moon and the sun, would constantly rise for instance the earth's interior. Our and fall, for one thing, and we would have extensive physics instructors and scientists taught us daily earthquakes. But, you will say, the earth's crust for years that the earth was once a huge is so solid that there may well exist a tide inside of molten sphere, just beginning to cool down. The in- the earth that we cannot perceive. This is hardly even terior and center is supposed to be entirely fluid -a probable, however, because in that case the gigantic huge molten mass where all the known elements "in- tidal; effects created -a million times greater than any cluding rocks" are in a liquid state, at a tremendously ocean tide-would burst thru the earth's crust in short high temperature running up into thousands of degrees order. Do not forget that if the orange peel analogy Fahrenheit. Our physics instructors by way of im- holds good, there will be a liquid mass some 7,000 tell us that the hard crust miles deep! Contrast that with the average depth of pressing us were wont to figure out of the earth is just about as thick in proportion to the ocean of less than one mile and then is to an orange. the gigantic tides. a liquid interior would produce! the rest of the earth as the peel He And in order that we could not doubt their words But our modern scientist does not stop there. our instructors give us "proofs" to back up their con- goes and counts the very few active volcanoes and finds that as ventholes for a molten globe 7,000 miles tentions. few First, we are pointed out that the volcanoes -the in diameter, they appear preposterous. These earth's interior -prove that holes could no more serve as vents for this big globe ventholes of the liquid straw. the earth is fluid inside. Witness the many volcanic than you could vent an armory with a soda eruptions belching forth molten rock, lava and brim- On top of this our astronomers come along and stone. And to further disarm our suspicions we are prove mathematically, without a shade of doubt, that shown that as we descend into the earth's interior, the the earth is at least as rigid as steel. temperature rises one degree Fahrenheit for every 40 But how explain the volcanoes and our deep hot feet. It matters not where we bore a hole or shafts? Our scientists prefer to think-and they can to 50 interior is not molten. interior ; the rise of tem- prove it, too, that the earth's sink a shaft into the earth's local molten perature as we descend is pretty uniform the world The volcanoes are merely ventholes for over, even in high latitudes. These are both facts, well pockets. The earth's heat is produced by radium, or authenticated and are not doubted by any sane person. rather radioactivity. And while the earth's interior is But recently scientists began wondering if these facts hot -very hot -it is not fluid. interior was in a molten While boring the famous Simplon tunnel, many hun- really proved that the earth's unbearable state. And the more they wondered the more they dred feet above sea level, the heat became i For one thing they said: If the earth's in- and artificial cooling became necessary. Recent tests learned. the rock could terior is really in a molten state, liquid in other words, showed that the radium contents of why does not this molten mass rise and fall with the easily produce this great heat. 'ward. it would do were it liquid or The solution of the earth's heat, then, doubtless is tides which undoubtedly H. GERNSBACK. even plastic. Accurate measurements, however, show radium.

p un , Ilpnnqll IIII U! ul un, u I,I,I,I,I IIIIII Illi\.IIIIIIh d iluI I IIÌiïll llllllllll I1III+ Ihugl =I: Vol. VII. Whole No. 84 Contents for April, 1920 No. 12 WATCHING PLANTS GROW Front Cover WEIGHING THE EARTH 1260 From a painting by Harold Brown By Louis E. Derr, Prof. of Physics, Mass. Inst. of Technology ELECTRIC POWER FROM THE SUN 1241 ELECTRIFYING CANAL BOATS AND BARGES 1262 BATTLE TRACER. 1242 By Robert G. Skerrett HEAT OF BODY DETECTED. 600 FEET AWAY 1244 TALKING OVER A SUNBEAM 1263 ONE MAN SUBWAY TRAIN 1245 By Prof. A. O. Rankine. Written especially for the ELECTRICAL WATCHING PLANTS GROW 1246 EXPERIMENTER. By a remarkably sensitive instrument devised by Sir Jagadis Bose, "AUTOMOBILE NEWS" 1265 of India POPULAR ASTRONOMY - OBSERVING THE HEAVENLY HELLO MARS! 1243 BODIES 1266 By H. Winfield Secor, Assoc. Member Amer. Inst. Electrical En- By Isabel M. Lewis, M. A., of the U. S. Naval Observatory gineers. "RABBIT CONTEST" AWARDS 1269 ELECTRICITY FOILS GERMAN SEALS 1251 Concluded from the March number By Fred C. Kelly PRACTICAL CHEMICAL EXPERIMENTS 1270 THE PHYSIOPHONE 1252 By Prof. Floyd L. Darrow By H. Gernsback HOME-MADE 110 -VOLT, 60 CYCLE INDUCTION MOTOR 1272 ELECTRO- MEDICAL FRAUDS 1254 By H. H. Parker By Joseph H. Kraus 1274 1256 THE "FINER WORKINGS STATIC ELECTRICITY THE EDUCATED HARPOON . aper. By Frederick von Lichtenow By Charles S. Wolfe Seco ELECTRIC BACHELOR MAID 1257 STORAGE BATTERY REPAI G Purdy By Henry Klaus By Edna MOTORS AND TELEGRAPH, CABLE AND RADIO DISPATCHES 1258 ELECTRICAL MACHINIST -NO. 6, ERECTING By Pierre H. Boucheron, Ensign U. S. N. R. F. SHAFTING. By H. Winfield Secor 1278 experiments; good is publisht on the 15th of each month at 233 tiens are paid for on publication. A special rate is paid for novel The ELECTRICAL EXPERIMENTER accompanying them are highly desirable. Fultotn Street. New York. There are 12 numbers per year. Subscription price is $2.50 photographs -class matter at the and foreign countries. $3.00 a year. U. S. coin ELECTRICAL EXPERIMENTER. Monthly. Entered as second a year in U. S. and possessions. Canada under Act of Congress of March 3. 1879. Title registered at the as well as U. S. stamps accepted (no foreign coin or stamps). Single copies, 25 cents New York Post Office of request. Checks and money orders Patent Office. Copyright. 1920 by E. P. Co., Inc., New York. The Contents this each. A sample copy will be sent gratis on should be not be reproduced without giving full credit to drawn to order of EXPERIMENTER PUBLISHING CO., Inc. If you change your magazine are copyrighted and must copies are not miscarried or lost. the publication. address notify us promptly, in order that The ELECTRICAL EXPERIMENTER is for sale at all newsstands in the United All m,+marlcntiens arm 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. 62 and 8A The Mall. Ealing, London. tions cannot be returned unless full postage has been included. ALL accepted contribu- Member of the Audit Bureau of Circulation. 1226 April, 1920 ELECTRICAL EXPERIMENTER 1227 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIII II IIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIililllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll!'

======.- THOUGHT The Greatest Commercial Product in the World By Charles F. Haanel

are, because you think. When yo u important and far -reaching truths of which 44 S teaching YOUcease that Mind is the dominat- to think, you cease to exist. Yo u the human mind can conceive. ing force are therefore is precisely in line with the what you think. wonders of Thought is the most recent psychology. a spiritual activity ; in fact, ONE reader says, "The All persons it is Master Key is having desks should have this the only activity which the spirit too modest a title for book thereon, possesses. such a stupen- and it would be a fitting All spiritual activities are crea- dous revelation "; another says, pocket companion." tive, because "It is the spirit is the one creative most wonderful teaching ever conceived"; Principle in the Universe. Thought is mind another says, GGYOU have led a hungry world to in motion just as wind is air in motion. the threshold and placed in their hands When a thought goes out into the world, a key it with which the understanding ones combines with other similar thoughts and may unlock the forms an idea. door and enter the Secret The idea then exists in- Place of the most high dependently of the thinker. and enjoy the This idea abundance of all good to be found therein." becomes a seed -thought in the spiritual world and as soon as it finds congenial soil, it THE Master Key is the answer to the begins to sprout and grow and demand, `Knock bring forth fruit a thousand fold. and it shall be opened unto you.' All the world seeks this wonderful key." I; OR this reason, we find that the men who hold the $50,000.00 positions are GGI HAVE found always the Master Key and men who think, who know how to with it I am each day unlocking the control their thought processes. A single storehouse of wealth and idea wisdom concern- is often of more value than all the ing which I was heretofore in utter ignor- lost mines of Mexico, all the argosies that ance." ever sailed from the Indies and all the silver- laden. ships of storied Spain. An idea GGTHE lash of circumstances and the has . life, vitality; it is the essence of the logic of events are more than ever creative spirit and can reproduce itself impelling men to think. exactly A philosophy of the same as a germ or a cell, so life having its basis blind that in an optimism, a re- increditably short time there ligion that won't work seven may be millions days in a of these ideas all clamor- week, or a proposition that is ing for self-expression. not practical, As thought is appeals to the intelligent, not all. creative, it is at It is constantly trying to express results that we want, itself in form. and the acid test is- For this reason thought will it work ? leads The Master Key qualifies! to action and actions bring about Intelligence rules! Thought results and conditions. intelligently directed automatically causes its object to manifest on a material plane." CIRCUMSTANCES and environment are, therefore, the result of thought, but GGYOU have synthesized the wisdom frequently of unconscious of and destructive the East and West thought for thought will create disagree- and given it in a able, discordant and destructive conditions, manner so logical and penetrating, that by just as readily as it will create wealth, its aid one is able to distinguish wisdom beauty, refinement and harmony. We may from sophistry, truth from delusion, spirit- think what we will, but the result is gov- ual expression from psychic vagaries, and erned by an immutable law. That we reap the sublime operations of spiritual insight what we sow is scientifically exact. and intuition from deceptive visions and false revelations. THOUGHT You have successfully was until recently the posses- taken the mystery out sion of the few, but of mysticism and it is now about to placed all propositions in become the priceless possession of the the clear light, many. so that 'He Until recently, the few assumed the priv- who runs may read.' I con- ilege of thinking for the many, but men sider you a true benefactor to the world." are beginning to do their own thinking and this is multiplying results and bringing I WANT the privilege of sending you a about a new era, an era containing limit- Master Key. You will find it a priceless possibilities. less possession, a Key with which many are converting THE loss into gain, fear into Master Key System is the only courage, despair clear, concise, into joy, lack into plenty, comprehensive, definite, hope into fruition, distinctive, exhaustive, original and a Key which thrills, scien- fascinates, carries tific presentation of the creative power of conviction, perception, thought ever formulated by anyone at any understanding, power, a Key by which you time. It is copyrighted will be enabled to in every civilized GGI AM able to extract from this System organize victory, realize country in the world, and is having an your ideals and make your dreams come almost all that can be made known by the unbelievable influence upon the lives finite mind true. Send me your address for a of relative to origin, evolution, copy, it the hundreds of thousands who are destiny and is coming into the much -mooted riddle of the free, there is no cost or obligation of an understanding of the most Universe." any kind. Charles F. Haanel, 203 Howard Building, St. Louis, Mo.

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Do you know the right and 1 [] Ferrin Home- Account System ($3) are offering you an opportunity to learn in By Wesley W. Ferrin wrong of complaints, esti- way presenting your own home how to improve your ability Name mates, and to issue orders? to Talk Convincingly. They are so con- .address Elect. Exp. 4 -20 You benefit bz mentioning the "Electrical Experimenter" when writ ig to advertisers. 1230 ELECTRICAL EXPERIMENTER April, 1920

You Can Learn Quickly by Our Practical Method IF you are a person of even average ability, you can master this profitable profession in your spare time at your own home through our famous "Home Study Course ". You can in a short time become a first class Draftsman because of the fact that our training is most thorough and practical, and because you will be personally instructed and coached by the President of the school, Roy C. Claflin, whose long experience as a draftsman and a teacher especially qualifies him to give you the kind of training you need. We Roy C. claflin, Presi- teach you to work from actual models just dent, The Columbia as you would in a drafting room, instead of School of Drafting merely copying from books. Draftsmen Get $35.00 to $100.00 a Week Every mechanical idea must be drawn out by the Draftsman before it can become a reality. On account of the importance of his work, he is therefore paid a good salary and is always in line for advancement. Drafting is not only one of the best paÿing professions, but is the stepping stone to bigger opportunities. Many men, receiving up to $40,000 a year and over, in technical positions, owe their success to their knowledge of Drafting as the starting point. How Columbia General construction companies, manufacturers of machinery, loco- motives, and automobiles, designers of tools and special equipment, makers of aeroplanes, large engineering companies; in fact, all branches Students Succeed of industry need DRAFTSMEN today in greater numbers and at better salaries than ever before. (More letters on request) "Columbia" Graduates Are the Kind of "I have accepted a position as draftsman, paying $2,640.00 a year to start. Draftsmen That Are Needed I had no previous drafting experience my training with you, The properly trained draftsmen, such as those graduated by the aside from are the ones who get the which has proven all that was needed COLUMBIA SCHOOL OF DRAFTING, a professional preferred- positions and best salaries, and are the ones who are most for me to become this draftsman." Lawrence P. Johnston. greatly in demand. The success of our students demonstrates fact. Columbia graduates are filling important positions in big con- the country. have offered me $40 cerns throughout "Several firms We would like to send you a book of testimonials from many of and $45 a week to start. As I am whose present highly paid up here our hundreds of students and graduates doing nicely as draftsman Draftsmen are the result of their practical training with to receive my second in- positions as and about A few of these letters are here reprinted. crease in salary have decided to stay. us. I find there are hundreds of openings for draftsmen and if I quit where I No Previous Training Required am I could secure another position in As our students are given practical Drafting work three hours' time. There will be a Drawing Outfit from the beginning of our course, they grasp the still greater demand for Draftsmen." Furnished Students essentials quickly, so that no previous training Geo. Murray, Jr. without or drafting experience of any kind is required to We furnish, You do not even extra charge, an indi- take up this work with us. "I wish to express my appreciation outfit to need a high school education to learn Professional sin- vidual drawing and the training for your courteous treatment and all our students for use Drafting as taught by this school cere interest in the progress of my the course. we give you is all that is needed to secure a posi- throughout P. Johnston's studies and for aiding me, upon com- This becomes y our tion as Draftsman (Read Lawrence pletion of your course, to secure a property as soon as the letter). very desirable position at $140 a course has been paid month to start. I am getting on well for. and the chances for advancement are excellent." A. L. Gash. Mail This Coupon Columbia School of Drafting Today 1100 14th T N. "I have accepted a good position Dept. and Sts., W., Your future success de- D. C. with a large manufacturing concern pends upon what you do, Washington, in Chicago and wish to thank you for TODAY. If you are inter- the training your school has given ested in learning this in- Without obligation to me, please send me FREE your teresting and big paying illustrated book of particulars, testimonials from stu- me." Emil B. Johnson. profession, send the follow - ing coupon WITHOUT DE- dents, rates and liberal terms. A few of our many her successful LAY for our Free catalog graduates are: of particulars. Name G. Tangorra, $2,800 a year; T. R. COLUMBIA SCHOOL OF R. Fowkes, Brown, $2,860 a year; DRAFTING Street & No. $3,700 a year. Dept. 1100 14th & T Sts. N.W., City State Washington, D. C. April, 1920 ELECTRICAL EXPERIMENTER 1231

Highly Paid Specialists RIG paying positions are open throughout the country to men who are experts in electrical starting, lighting, ignition and storage battery work for automobiles, motor trucks, tractors, motorcycles, motor boats, aircraft, farm lighting plants and gas engines of all types. Here is a great new field of highly paid specialists where there are not enough trained men to supply the demand. Automotive electrical experts are needed by automobile and gas engine manufacturers, service stations and garages. No less than 75% of all automobile troubles are electrical and require the services of the expert who understands every detail of automotive electrical equipment; its construction, principles of operation, methods of testing, its care and repair. Earn $150 to $400 a month You can qualify for the big opportunities in this clean, Interesting work. You can quickly become a master of electric starting, lighting, Ignition and storage batteries and step into a big paying position as a trained specialist in the highest branch of auto mechanics. You can go into business for yourself, if you choose, for there is a big demand everywhere for expert electrical repair service. In Three Months You Can Be A Master Of All Starting, Lighting and Ignition Systems and S toralte Batteries Our method of intensive, highly specialized training under everything, from the fundamental principles of electricity practical experts in our big, fully equipped laboratories to the most intricate problems in construction, operation, makes you a master of every phase of automotive and gas short months, by -devoting full engine electrical equipment. You learn by actual work on testingg and repair. In three models of every type of system in use. You are taught time to your training, you can be an expert. Come to American's Greatest Institution of Electrical Education Train for your future as an automotive electrical expert Engineering of Milwaukee with its fifteen year record of in the largest and most completely equipped institution of training men for success in all branches of electricity. its kind in the country. Nowhere else can you get the Four big buildings -1500 students-over 75 instructors. tremendous special advantages offered you .by School of Dormitory and other special privileges. Students' athletics. secure part-time Earn While You Learn p, y em- Milwaukee industrial concerns to defray your expenses if you wish. You can devote half time to earning money and half to your training in automotive electricity, completing the course in six months. Most of our students are earning their own way. You can take advantage of the same wonderful plan while you are training for a splendid future as a highly paid expert. As soon as your course Is completed our Free Employment Bureau helps you to a good position. We have hundreds of requests from employers for men trained by School of Engineer. ing of Milwaukee. Write for Big FREE BOOK .his mail tiir eonp r uiitr for our handsome illustrated Book telling about the great opportunities for you as an Automotive Electrical Expert, explaining our practical method of training and our Earn SCHOOL OF ENGINEERING While You Learn Plan. Read about the great Ì School of F,ñgineering, its up -to -date electrical j OF MILWAUKEE laboratories and its unparalleled layout of elee- ¡ Dept. 14, 373 Broadway, tricot equipment for you to work with. Do not / Milwaukee, Wis. Pass by this opportunity to learn of the big is Please send me, without [root or ob- future that will be opened to you by only a Ftee Book 11gaUon on ectr, your few short weeks of intensive, specialized train- on Automotive Electricity. telling about Ing in automotive electricity. New classes the opportunities open and your method forming now. Tear off the coupon and ,r( of practical training. Also particulars of mail it today -your request involves no your Earn while You Learn Plan. cost or obligation. ; I A corner of our laboratories showing students ./ 1 at work w;th various types of automotive elec- di Nanse trical equipment. SCHOOL OF ENGINEERING OF MILWAUKEE Address Dept. 14, 373 Broadway, Milwaukee, Wis. I TOM 1 State Yon benefit by mentioning the "Electrical Experimenter" when ,rriting to advertisers. 1232 ELECTRICAL EXPERIMENTER April, 1920

It contains the following 44 chemicals: Alum Al2(SO4)s. (NH4)2SO4 Antimony (powdered) (Sb) Ammonium Aqua (NH3-1-H20) Ammonium Carbonate (NH4)2 CO3 Ammonium Chloride (NH4C1) Ammonium Sulphate "The Joy of Father and Boy." (NH4), 504 Barium Chloride (BaCla) Boric Acid (H3B02) Brimstone (Sulphur) (S) Calcium Chloride (CaCI3) Calcium Oxide (CaO) Calcium Sulphate (CaSO42 H2O ) Chemical Laboratory Charcoal (Carbon) (C) Chloride of Zinc (ZnCl2) Copper Sulphate (CuSO4) We present herewith to our friends our new E. I. Co. Chemical Labora- Ferrous Sulphate (FeSO4) tory which contains real chemicals and Ferrous Sulphide (FeS) apparata to perform real chemical Glycerol (Glycerine) experiments. This outfit is not a toy, put up merely to amuse, but a CaH5(OH)a practical laboratory Hydrochloric Acid (HCI) set, with all the chemicals, apparata and reagents Iodine (1) necessary to perform real work and to Iron Chloride (FeCl2) teach the beginner all the secrets Iron Oxide (Fe202) of inorganic chemistry. With this outfit we give free a book containing Lead Acetate Pb (C2143O2)2 a Litmus Paper Treatise in Elementary Chemistry, useful data and recipes, and 100 Magnesium Carbonate instructive and amusing experiments. (M gCO3 ) Manganese Dioxide (MnO2) Mercury (Quicksilver) (Hg) DESCRIPTION OF THE OUTFIT: Nickel Chloride (NiC12) The Oxalic Acid (H2C204) outfit consists of forty -four (44) Chemicals all A good part of the book is devoted Sodium Bicarbonate C. P. (chemical pure) put up in appropriate wooden to Weights and boxes, glass bottles, and hermetically Measures. The Metric System, the English system (NaHCO3) closed jars. The and the U. S. System Sodium Borate (NaBO2) acids are put up in glass bottles, with ground -in glass are fully explained. Sodium Carbonate (Na2CO2) stoppers and there is a sufficient quantity of chemicals The following supplied (mostly one to two ounces) tables are furnished: Symbols and Sodium Chloride (NaCI) enough to make Atomic weights of the Elements; Measures of Weights, Sodium Nitrate (NaNO3) dozens of experiments with each. See list of Chemi- Sodium Phosphate cals herewith. _Volume, Capacity and Length; Per Cent solutions; The apparata furnished are all Conversion of Measure expressed in parts; Poisons (Na2HPO4) of the best obtainable and Sodium Sulphate (Na2SO4) make and of standard laboratory size and shape. A their antidotes; Technical and common name of Sodium Sulphite (Na2S03) list of the 17 pieces of apparata furnished with this chemical substances; Formulas for Cleaning various Stannous Chloride (SnCl2) outfit is printed also herewith. substances, etc., etc. Sulphate of Nickel (NiSO, The Instruction book is a real Chemistry Course Sulphate of for the Beginner. Some of the Contents are: Divi- Among the 100 Experiments are: Zinc (ZnSO4) sion of Matter: This is Sulphuric Acid (H2SO4) a Treatise on Elementary How to make chemical tricks; How to make invisible Tin (Granulated) (Sn) Chemistry and deals with the theory of the Ele- ments, Molecules and Atoms, etc. Chemical and magic inks; How to test flour; How to test soil; Zinc (Metal) (Zn) Nomen- How to Make Chlorine Gas and smoke Zinc Carbonate (ZnCO3) clature: This explains in simple language the deri- (German War vation of the chemical names of the Elements and Gas) ; How to bleach cloth and flowers. How to pro- their compounds. There is a chapter on Laboratory duce Oxygen and Hydrogen; How to make chemical The following apparata Operations; Glass Working; First Aid; Fire Ex- colors; How to test Acids and Alkalies and hundreds are furnished: tinguishers; Experimenters' Aphorisms, etc. of interesting hints and formulas. One Standard Washbottle One Alcohol Lamp The price is still One Conical Glass Measure $5.00. Shipping Weight 10 lbs. (Can be shipped by Express only.) One Erlenmeyer Flask One Glass Funnel One Delivery Tube Six Assorted Test -Tubes One Test -Tube Holder Ten Sheets of Filter Paper THE ELECTRO IMPORTING CO., Mfrs. One Glass Dropper One Spoon Measure 231 Glass Tubing TRADE MARK FULTON STREET NEW YORK CITY One book containing Trea- tise on Elementary Chemis- try and 100 Chemical Ex- "THE LIVELIEST CATALOG IN AMERICA" periments to be performed Our big, new electrical cyclopedia No. 21 Is ELECTRO IMPORTING COMPANY with this waiting for 231 Fulton St., New York City outfit. 3ou. Positively the most complete Wireless and electrical catalog in print today. 176 I enclose herewith 6 cents In stamps or coin, to 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 -page NAME FREE Wireless Course in 20 lessons. FREE Cyclopedia ADDRESS -92.1,4,,,zr. No. 21 measures 7x5t/4 ". Weight 3e lb. Beautiful stiff covers. STATE E.E. 4 -20

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1 92 ELECTRICAL EXPERIMENTER 1233 A Startling MemoryFeaE That '}&z (Pan Do How I learned the secret in one evening. It has helped me every day ON THE way home that night others. Time and time again I have won people to I my way of thinking simply because I could instantly asked Macdonald how it recall facts and figures. While I'm proud of my was done. He said there was triumphs in this respect, I often feel sorry for the really nothing to it - simply a ill -at -ease look of the other men who cannot hold memory feat, the key to up their end in the argument because they cannot which recall facts instantly. It seems as though I never anyone could easily learn in one forget anything. Every fact I now put in my mind evening. Then he told me that is as clear and as easy to recall instantly as though the reason most people have bad it were written before me in plain black and white. We all hear a lot about the importance of sound memories is because they leave judgment. People who ought to know say that a memory development to chance. man cannot begin to exercise sound judgment until Anyone could do what he had he is forty to fifty years of age. But I have dis- done, and develop a good proved all that. I have found that sound judgment mem- is nothing more than the ability to weigh and judge ory, he said, by following a few facts in their relation to each other. Memory is the simple rules. And then he told basis of sound judgment. I am only thirty -two, me Ixactly how to do it. At the but many times I have been complimented on having the judgment of a man of forty -five. I take no time I little thought that evening personal credit for this -it is all due to the way I would prove to be one of the trained my memory. most eventful in my life, but * * * * * * * such it proved to be. THESE are only a few of the hundreds of ways I have profited by my trained memory. No longer What Macdonald told me I do I suffer the humiliation of meeting men I know took to heart. In one evening I and not being able to recall their names. The made remarkable strides toward moment I see a man his name flashes to my mind, improving my memory and it together with a string of facts about him. I always liked to read but usually forgot most of it. Now was but a question of days be- I find it easy to recall what I have read. Another fore I learned to do exactly what surprising thing is that I can now master a subject he had done. At first I amused in considerably less time than before. Price lista, market quotations, data of all kinds, I can recall in myself wth my new-found ability detail almost at will. I rarely make a mistake. by amazing people at parties. My vocabulary, too, has increased wonderfully. WHEN my old friend Faulkner 'nvited My "memory feat," as my friends called it, Whenever I see a striking word or expression, I me to a dinner party his memorize it and use it in my dictation or conversa- at house, I surely made a hit. Every one was talking tion. This has put a remarkable sparkle and little thought it would be the. direct about it, and I was showered with invitations pulling power into my conversation and busi- means of getting me a one -hundred-and -fifty for all sorts of affairs. If anyone were to ask ness letters. And the remarkable part of it all per cent. is that I can now do my day's work quicker and increase in salary. Yet it was, and me how quickly to develop social popularity, with much here is the less effort, simply because my mind way it all came. about. I would tell him to learn my memory "feat" - works like a flash and I do not have to keep stopping Toward the close of the evening things began but that is apart from what I want to tell you. to look things up. to drag a All this is extremely satisfying to me, of course. bit, as they often do at parties. The most gratifying thing about the im- But the best part of it all is that since my memory Finally some one suggested the old idea of provement of my memory the power first attracted the attention of our president, was remarkable my salary has steadily been having everyone do a "stunt." Some sang, way it helped me in business. Much to my increased. Today it is others forced weird many times greater than it was the day Mac- sounds out of the piano, surprise I discovered that my memory training donald got me interested in improving my memory. recited, told stories, and so on. had literally put a razor edge on my brain. * * * * * * * Then it came to Macdonald's turn. He was My brain had become clearer, quicker, keener. WTHAT Macdonald told me that eventful evening a quiet sort of chap, was this : "Get the Roth Memory Course." I with an air about him I felt that I was fast acquiring that mental did. That is how I learned to do all the remarkable that reminded one of the old saying that "still -grasp and alertness I had so often admired in things I have told you about. The publishers of the waters run deep." He said he had a simple men who were spoken of as "wonders" and Roth Memory Course -The Independent Corporation "stunt" which -are so confident that it will also show you how to he hoped we would like. He "geniuses." develop a remarkable selected me to assist him. memory that they will gladly First he asked to be The next thing send the Course to you on approval. blindfolded securely to prove there I noticed was a marked im- You need not pay a single penny was no provement in my conversational powers. until you have trickery in it. Those present were to call out For- examined the Course and found that it fully lives twenty -five numbers of three merly my talk was halting and disconnected. up to all the claims made for it. Send no money. figures each, such I never could Merely mail the coupon or write a letter, and the as 161, 249, and so on. He think of things to say until the complete Course asked me to write conversation was over. And will be sent to you instantly, all down the numbers as they were called. then, when it was charges prepaid. If after examination you decide too late, I would always think of apt and that you do not want to keep the Course, then return This was done. Macdonald then astounded striking things I "might have said." it and you will owe nothing. On the other hand, if But now you as everyone by repeating the entire list of twenty - I can think like a flash. When I am talking find, thousands of others have found, that five numbers backwards I the Roth Memory Course will do wonders for you, and forwards. Then never have to hesitate for the right word, the then merely send five he asked people dollars in full payment. to request numbers by posi- right expression or the right thing to say. It You have always wanted a good memory. Now tions, such as the eighth number called, the seems that all I have to do is to start to talk you can have it. Remember, you pay no money fourth number, until you have proved that the Course will benefit and so on. Instantly he re- and instantly I find myself saying the very you. You have peated back the everything to gain and nothing to exact number in the position thing I want to say to make the greatest im- lose by taking immediate action. So mail the called. He did this with the entire list -over pression on people. coupon NOW before this liberal offer is withdrawn. and over again, without making a single mis- INDEPENDENT CORPORATION, Dept. R -1104, take. It wasn't long before my new -found ability EXAMIErio319 Sixth Ave. to remember things and to say the VFREEY. 1.., COUPON Then right thing Macdonald asked that a deck of cards at the right time attracted the attention of our be shuffled and called INDEPENDENT CORPORATION out to him in their order. president. He got in the habit of calling me Publishers of The Independent Weekly This was done. Still blindfolded, he instantly in whenever he wanted facts about the Dept. R -1104, 319 Sixth Avenue, New York named the cards busi- You may send me the Course or Courses checked below. in their order backwards and ness. As he expressed himself to me, "You Within live days after receipt I will either remail them or forwards. And then to further send you $5 for each in full payment. amaze us, he can always tell me instantly what I [ ] Roth Memory Course gave us the number want to of any card counting from know, while the other fellows annoy me by By David M. Roth the top, or the card [ ] How to Read Character at Sight for any number. dodging out of the office and saying 'I'll look By Dr. K. M. H. Blackford it [ ] Mastery of Speech You may well imagine our amazement at up.' By Frederick Houk Law a Macdonald's [ 1 Super -Salesmanship ($7) remarkable feat. You naturally * * * * * * * By Arthur Newcomb 'r expect to [ ] Course In Personal see a thing of this sort on the stage, IFOUND that my Purinton Efficiency and even then you look ability to remember helped By Edward Earle Purinton upon it as a trick. me wonderfully in dealing [ I Ferris Home -Account System ($3) But to see it done by with other peo- By Wesley W. Ferrin an everyday business ple, particularly in committee meetings. When man, in plain view of everyone, blindfolded a discussion Name and under conditions opens up the man who can back which make trickery im- up his statements Address possible, is quickly with a string of astonishing, to say the least. definite facts and figures usually dominates the F.lec. Exp. 4-20 You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1234 ELECTRICAL EXFERIMENTER April, 1920 t

20 Cents APRIL RADIO 1920 Over 100 Illustrations Edited by NEWS H. GERNSBACK The 100% Wireless Magazine"

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and circulated. , APRIL ISSUE: Each issue of the RADIO AMATEUR NEWS now contains 72 pages (or more) and an artistic cover in two colors. The illustrations average 120 every month and there are from 40 up -to -date articles, some by our greatest radio scientists, in every issue. A Modern Radiophone to 50 is the greatest and biggest radio magazine in print today. By Robert F. Gowen RADIO AMATEUR NEWS RADIO AMATEUR NEWS is the only INDEPENDENT monthly wireless magazine in no commercial interests has no boss save its readers. It is "differ - existence. It caters to -it caters largely to the The Resonant Converter Trans- ent " -it has the latest radio news. It is a scientific magazine but it RADIO AMATEUR-it is by and for the Amateur. It is published by the publishers of the mitter ELECTRICAL EXPERIMENTER, but there is no duplication of articles in the two magazines. both together will give you ALL the radio news of all the Both are entirely different -but or order it from your Station world. Whether you are a professor or an Amateur, get a sample copy New Facts About Nauen Newsdealer today. By Dr. Alfred Gradenwitz Wireless in Modern Aircraft $100.00 RADIOPHONE PRIZE CONTEST *Radio telephone, there is no doubt about that. With the By Alexis J. Hall The future of Radio lies in the message M Radiophone there is practically no interference; you need learn no code; a radiophone N takes but a fraction of the time of a radiotelegraph message. M New Reactance Transmitter NEWS is so enthusiastic about the Radiophone, and he a The Editor of RADIO AMATEUR IN GOLD for the best . By E. T. Jones its future, that he has offered $100.00 is such a staunch believer in great Here is your chance for some photographs and description of a good amateur Radiophone. The Priess Loop Set 4 easy money. -Part RADIO AMATEUR NEWS. By Walter J. Henry For full particulars see this month's issue of 8M Aladdin's Lamp 20c SEND 72 PAGES By Charles S. Wolfe The COPY 20c FOR 128 ILLUSTRATIONS $2.00 SAMPLE 1 uSPECIAL OFFER i. ", With the Amateurs A Year gentlemen: COPY Please enter my subscription for RADIO AMATEUR Canada and Forel2n NEWS for the term for one year for which I enclose is $2.50 A Year TODAY herewith $2.00. As a special offer you will also send ins for 25c extra your great Wireless Course containing 160 pages 350 illustrations. size 6ÿa x 10" with fine PUB. CO., 231 Fulton St., New York City flexible cloth cover. I have written my name and, EXPERIMENTER address in margin below. IIM iIIII IIIIIIIIIIIIIIIÌIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIiIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIllllllllltllli 1 - - - u - You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. / , April, 1920 ELECTRICAL EXPERIMENTER 1 2 3 3

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CONTENTS

The National Electrical Code, with all its new rules, is explained and illustrated. 52 of the latest and simplest tables which show, at a glance, just what size of wire is needed for any kind and size of lighting, motor or heating installation, for any voltage, current and drop desired for any system, Direct Current, Al- ternating Current, single, two or three -phase. The latest Code Rules on grounding required on all work.

SPECIAL CHAPTERS

How to install and operate generators, motors, storage batteries and every kind of .wiring device with diagrams of connections. Illumination, House Wiring, Garage Wiring, Theatre Wiring, Moving Picture House Wiring, Sign Wiring, Marine Wiring, Electric Range and Heater Wir- ing, Watt-Hour Meter Wiring and complete chapters on inside and outside wiring for every system from a central station to the smallest cottage. Electrical Units and their Equivalents. The latest lamp data. Proper symbols to use to indicate outlets, etc., etc. Also a complete directory of the leading manufacturers of officially approved apparatus and supplies necessary for any kind of installation. ACTUAL SIZE

THE ONLY COMPLETE LEATHER COVER- POCKET SIZE AND ACCURATE BOOK 440 PAGES -FULLY ILLUSTRATED ON WIRING PUBLISHED GILT EDGES -PRICE $3.00 Sent Post -paid to Any Address on Receipt of Price by H. C. CUSHING, JR., 8 WEST 40TH STREET, NEW YORK CITY Every Electrical Inspector in the United States will approve your work if done in accordance with the simple rules given in "Standard Wiring"

von benefit by mentioning the `Electrical Exberimenter" when writing to advertisers. 1236 ELECTRICAL EXPERIMENTER April, 1920

Here Are 3 Books You Should Have For a limited time we will send all three for only 50c when included with a one -year subscription for the DESIGN- CONSTRUCTION ELECTRICAL EXPERIMENTER. This offer is limited time. Don't wait, get AUDIDN AMPLIFYING TRANSFORMERS -it may be withdrawn at any RADIO AND AUDIO FREQUENCY TYPE these books NOW and guarantee yourself twelve wonderful numbers of the ELECTRICAL EXPERI- MENTER.

Design and Construction of Audion Amplifying Transformers Radio and Audio Frequency Type

by E. T. Jones, late Associate Editor of 254 RADIO AMATEUR PUBLISHED BV THE EXPERIMENTER PUBLISHING CO. INC. N E W S, a wonderful 233 FULTON ST. NEW YARN CITY book -the only one of its kind in print- should be on the shelf within easy reach of every amateur. Every line of this book is written so that you can understand it. Every detail in the manufacture and construction of Au- dion Amplifying Transformers is described at great length. The book contains many illustrations and diagrams that make it a simple matter to build the Transformers described. Never before have these instruments been described in print. They have always been considered strictly a "trade secret."

How To Make Wireless Receiving How To Make Wireless Sending Apparatus Apparatus A wonderful book for the man who in every detail equal to "How To Make would construct his own apparatus. Size Wireless Receiving Apparatus." Size 51/4 51/4 x 71/2 inches. Containing 100 pages x 7 V2 inches. Containing 100 pages and and 90 illustrations. Compiled of the 88 illustrations. Dealing at length on writings of twenty -five Radio experts. Quenched Spark Gaps, Rotary Gaps Every amateur should have this book in his and Oscillation Transformers. wireless room. Any amateur in the "wireless game" can easily construct a complete sending and receiving station, and will have his choice of many varieties after reading these wonderful books. Remember, all three will be sent you postpaid just as soon as we receive Exre, imenter 50 cents toward the cost of the books. You Publie hi ng Co., your subscription and 233 Full on St., really get the books free, because the magazine alone would cost New York, N. Y. you $3.00 if you bought the single copies each month. Gentlemen ou may send me the three books described in the "Experi- menter" and enter my name EXPERIMENTER PUBLISHING CO., Inc. for a year's subscription to t h e ELECTRICAL EXPERI- 233 Fulton Street, New York City, N. Y. MENTER MAGAZINE for which I enclose $3.00. Name

Address

to advertisers. You benefit by mentioning the "Electrical Experimenter" when writing April, 1920 ELECTRICAL EXPERIMENTER 1237

Try This Lesson Now Only 7 Lessons Easily Take the ordinary longhand letter inate everything ...re Elim- but the long downstroke will and there remain This is the Paragon symbol 7 Evenings D. It is always for Learned in written downward. From the longhand You don't need to go to an expensive school to learn shorthand. You don't need to spend letter .0 rub out thing except the every- hours and hours in mental grind trying to master a lot of lines, shadings and hooks. upper part-the circle -and will have the Paragon you You can gratify your wish to learn shorthand -to be able to take short notes or long speeches E. a Write this circle at the speedily and correctly by learning only 7 easy, fascinating Paragon Shorthand lessons. beginning of you will have Ed. f and It's the ideal course for busy executives, reporters, advertising writers, secretaries, authors, 13y letting the circle remain open it will clerks, ambitious boys and girls-anyone and everyone who realizes the tremendous advan- and this hook be a hook, stands for A. Thus tage one has in ability to make quick and correct notes for later reference. Ad. Add another will be A at the end, thus will have ./ and you Anyone who knows the alphabet can quickly master the principles of the Paragon Course. a girl's name, Ada. There are twenty -six letters in the alphabet and From eliminate . the initial and final and o will remain, strokes which is the for O. Paragon symbol For the longhand Only 26 Word Signs --772-- which is strokes, you made of 7 use this one horizontal Therefore, stroke _ in the Paragon Shorthand method-six prefix abbreviations -and one general rule for con- would be Me. Now tractions. You grasp the principles the first evening- within the first hour. Practice daily continue the E across the M, so as to add gain great speed. Each is so D- thus and what you learn in each lesson and you very quickly sign easy 7` you will have Med. the large circle Now add to remember that you don't need to consult the book for the correct word sign -each one for O, and you will (medo), which have just pops into your mind as you require it. It's just like playing an interesting game. But is Meadow, with omitted. the silent A and W you can make the knowledge pay you big dividends by using it in your daily work or stepping up to a position that requires a knowledge of shorthand. Paragon writers are all over the world: in England, Continental Europe, Australia, New Zealand, Canada, South Amercia, Canal Zone, China, Philippine Islands and in all other civilized places. Paragon Shorthand is used in the offices of Standard Oil Company, United States Steel Corporation, many of the great Railway Systems, the largest firms and corporations in the world. Paragon Shorthand Only $5.00 For the price of a couple of theatre tickets you can get this knowledge and ability You can quickly master the Course at home -in that will prove to be of inestimable value to you almost every day in your life. seven evenings -just as thousands of others have Many of the big men in business got their start done. because they could write shorthand -Frank A. Through this Paragon Course you can write Testimonials Vanderlip, George B. Cortelyou, William Loeb, Jr., without mental friction-you have no compli- Used in Government Service Edward Bok and many other very successful men. rules to remember, no "lines" to watch, no 'Z learned Paragon Shorthand cated from the Home -study Course - The man or woman who can write shorthand has an heavy and light "shadings." Only 26 simple word - the lessons alone-without any confusing further aid whatever. At the end advantage over those who can't write, every time. signs, with no tedious memorizing, no of a week I could write the system Thousands of ambitious men and women who of meanings through the old elimination of nicely. I am now using it in the Government service, Treasury absolutely failed to learn the old, complicated vowels. Paragon notes never get "cold "; they Department, Washington, D. C., forms of other systems of learned read after ten years as after and am getting along O. K. On shorthand have are just as easy to account of my efficiency as Paragon with ease. They have since become court ten minutes, and the complete price of the Course stenographer my salary has been increased. I owe my rapid ad- stenographers, reporters, assistants to business is oily $5.00. vancement to Paragon Short - heads, executives of prominent concerns and in- hand."-E. C. Alley, Room 426. , Winder Building, Washington, D.C. stitutions. Thousands of grateful letters have been Send No Money and mail the In Court Reporting written highly recommending the Paragon Course Don't send one cent now. Simply fill in "T Coupon and the Paragon Shorthand Course will be mailed have been the official Court and the financial reward that the use of it has it for five . Reporter for the Ninth Judicial to you for your personal examination. Keep District of Louisiana for a num- brought. days -test the lessons and see for yourself how rÌ ber of years, using Paragon Short- Large and small business houses are searching quickly you can get the knack of writing Paragon hand exclusively. Some years ago your newly -found knowledge. /Paragon I learned this system in seven for efficient shorthand writers. They are willing Shorthand. Use Shorthand lessons. With Paragon Shorthand to pay any salary within reason for the service Then, after the five days, send us live dollars 'I Institute 1 am able to do any kind of work as fall and complete payment of the Course, with as great rapidity as the which they must have. Salaries are steadily ad- Home Study Mar- you may return the Course to us with- Y occasion may demand. " -J. Dept. G- 1 103, tian Hamley, Lake Providence, La. vancing -and yet the demand for shorthand writers out owing us one cent. You can't lose / cannot be supplied. This unfilled demand is your by sending for the Course for the / 3Ii 6th Ave. In Public Schools five days' free examination. You New York. 'As a result of competitive opportunity. / Paragon Shorthand was will gain by a complete knowl- tests, edge of Paragon Shortland. unanimously adopted as the ex- ¡ Shorthand Course for my clusive system for the Atlanta Formerly $25.°° Send the Coupon. "personal examination. High Schools. The classes we After have already graduated in Para- 00 a five days I will either send you Paragon Shorthand $5.00 in full payment gon are by far the best we have Now $5 Institute of the turned out during my twelve Paragon Shorthand, which we offer you for # Course or I will return it to you years' connection with the and I will not owe schools. " -W. C. Lowe, Head $5.00, is exactly the same course that has been Home Study of the Shorthand Departments, you any money or be Hopi. ¡ in any way. taught by the inventor, Alexander Lichten- obligated 18 Avery Drive, Atlanta, Ga. Mr. G-1104, On Big Corporations tag, charging a fee of $25.00 for the Course with 311 -6th "I am getting along fine with separate examinations after each lesson. This Ave., Name Paragon Shorthand. It is all you claim for it. It is easy to write, Paragon Course is Mr. Lichtentag's identical N. Y. and as for speed- there's no limit." -John Waller. Jr.. Stand- Course arranged into Seven Easily- Learned Les- /4.Address ard Oil Co., Sugar Creek, Mo. sons, and an ingenious self -examination method. ,' Town Elec. Exp. 440 You benefit by mentioninn the "E1gctrieal Experimenter" when writing to advertisers. 1238 ELECTRICAL EXPERIMENTER April, 1920

NAME ADDRESS e STATE F(LL IN THIS COUPON E L E C T R O IMPORTING COMPANY, FOR 231 Fulton St., New York City. I enclose herewith 6 cents in stamps or YOUR COPY OF coin for which please send me your latest Cyclopedia Catalog No. 21 con- New taining 176 pages, 263 illustrations Our 176 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 `ul I size fac- simile of our catalog just as it looks when 20 lessons. . you get It 1!n.}-20 1- 2 INCH THICK WEIGHT . ALMOST 1 -2 POUND IM 263 Illustrations

A Few Interest- a_ ing Things from Catalog No. 21 Treatise on Wireless Te- legraphy by B. Gems- back, Editor Electrical Experimenter and Ra- dio Amateur News- 13 big pages, 3 illustrations. The Wireless Law of 1912 -all a bout 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 power stations. How to receive time signals by Radio. How to construct an amateur aerial. How to use the test buzzer. How to join the 'Radio League of America" FREE. including application blank_ How telephone receivers are wound and built, tested and magnetized, 3 pages, 2 illustrations. Experiments with a pony telephone receiver, with 8 illustrations. Wireless Codes: Morse, Continental, Navy. Experiments with spark coils, 3 pages. How to photograph electrical discharges (sparks). All about storage batteries, how t o t e s t them, recharging, etc. Teals experiments, 2 pages. How to make Selenium Cells (illustrated). with FREE u l cyyc a=ne 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.

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( 11i!E I(ÍIII0I(II "THE The Elpcf ïo InmorÍín Co. [WEST 231 FULTON STREET NEWRK'O CATALOG "EVERYTHING FOR THE EXPERIMENTER" IN AMERICA" IN this cyclopedia you will find 116 pages E. L Co. for quality and workmanship. Talkers, High Frequency Apparatus and all about radio. One of the greatest supplies, Heating Pads, Electro- magnets, catalogs Other things you will find listed in this 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 them in 1904. tifiers, CO. Rheostats, Tesla Coils, Nickel Plat- 231 FULTON 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"

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 12 3C) How Would You Like to Earn 3QQ Next Week? did it one day, and in 4 years jumped to almost $1,000,000 Col. S. W. Wilke Let a year. S. E. Gibson jumped his earnings from $150 to $800 a month. me send you my secret of earning more money, to try 5 days Free. All you risk is a two cent stamp. By A. L. Pelton worth while. that will -power is the mighti- to gain, if the book was MY name is discovered So the orders came in by the hundreds - Pelton est force men have ever known. then by the thousands. - my- orders behind -just Albert L. Pelton. I was fooling myself- cheating At times I was 15,000 self fearfully, as I found out later. couldn't print books fast enough. Four years ago I from readers came pouring in so One day I ran across a man who had pur- And letters as as a back. fast I simply couldn't read them all. Col. S. was poor chased the book from me a few months that one the street and said, W. Wilkie of Roscoe, S. D. wrote church mouse. I He stopped me on Will" netted him say, I'd like to have another day's study of "Power of was of a job, "Hello, Pelton, that four years later, by using out copy of that Haddock book,-can you send $300 cash, and the methods Haddock formulated, his earnings $300 in debt, and it up right away ?" V. P. Then I asked him had risen to nearly $1,000,000 a year. my wife and two I told him I would. wrote, about one it. Coffin of Rochester, N. Y., were liv- casually if he liked the book `Power of Will's children What he told me made me go home and month after getting -" already has produced an increase of $5,000 a' ing on starvation read the book myself-for the first time since of San it twelve years before. year in my income." J. F. Gibson -ations. known the bitterest I began to sell since reading "Power of evening I borrowed $300. Diego, Cal., said that That same jumped from $150 to $800 a kind of want. The next day I was in New York. Will" his salary Today I have money and all that I secured the exclusive selling rights to the month. home. Men like Judge Ben Lindsey, Supreme money will buy. I have my own book. General "ad" in the Court Justice Parker, Asst. Postmaster- I have no worries about high prices of Then I spent $150 for a page Nebraska, Sena- magazine. Britt, Governor McKelvie of or rent. Review of Reviews Secretary of Agriculture food or clothing It brought me about $2000 in cash. tor Capper of Kansas, make another nickel, Meredith, Governor Ferris of Michigan-and Even if I never As fast as the money came in I shot it of have to worry a host of other big men, show the class I don't think I will ever back into advertising. Haddock's methods. I got $2500 in cash I bought a half leaders who have studied about money matters. When must be something in "Power page "ad" in the Saturday Evening Post. Surely there During the past three years I have of Will" for you, my reader. The first year I spent $50,000 in advertising. a million been making on an average of over a nearly a hundred It helped me. It has helped half The next year I spent a circular mailed a week. others. I could send you thousand dollars thousand. of letters from readers. But, time I I guess I've spent over half a million dollars with hundreds That's quite a change from the still, see the book and read it 5 days since my first $150 "ad ", and already 450,000 better was "on my uppers ", isn't it? great executives, free. men and women-including you don't think "Power of Now let me tell you how I did it. international diplomats, famous authors, etc., All you lose, if will increase your earnings, is a two You will probably think I'm funny also have taken up this study. Will" I At first some people said I was crazy to cent stamp. when I tell you that for twelve years It may make $300 for you next week -it secret that at last advertise that book. upwards to $50,000 or held in my hand the found that the book was selling might carry you When they few years don't know. I do won me riches. I was spending as high as $20,000 $100,000 in a -I -and that it has made a lot of money for its But it's true. a month telling people about it, they said I know I struggled -with had more nerve than sense. readers. For twelve years too, that if you pass this offer my hand. But, my friends, all this time I was simply I do know, gold right in medicine. by you are a scoffer and a doubter -I will taking my own -if a It was this way. telling people that the will was the lose only the small profit on the sale of I was the difference I used to sell books-from door to motive power of the brain -that a strong will book -but you -you may lose money and real money. door -eking out a poor man's living. could batter down every obstacle to success- between peanut written that weak will -power could be made strong, It costs only 2c stamp to mail the coupon. One of the books I sold was could be as easily as the muscles of the arm Don't wait 12 years -as I did. You may by Dr. Frank Channing Haddock. made strong -and that most people had weak and not know it. the book have gold within your reach I never thought much about wills made strong -and that simply because Send for "Power of Will" Low. You've seen -although I sold a few from week to they didn't use their will power. my ads before -now answer this one and see and was week. I had strengthened my own will if this masterful volume loesn't contain the people were calling me "crazy ". to make your For twelve years I never even took the using it when one little push you may deed And it was my will power that people called life rosy -red. Begin training your will by trouble to read it. "nerve ". sending in the coupon this very second. It was called "Power of Will ". Anyway, it was the secret of my success. A. L. PELTON. I didn't know anything about will Without it I might still be plodding - still canvassing. power. Or even if I had gotten up enough courage Publishing Co. more, I didn't care. I might have made only a piker's Pelton What's to advertise Meriden, Conn. I thought it might be a good book for success. 30 -H Wilcox Block, the who had to read it. It was my will power that got me $300 fellows loan. But I was too busy earning a living It was my will power that got me exclusive Pelton Publishing Company Block, Meriden, Conn. to bother about will power. sale of Dr. Haddock's book. 30 -H Wilcox power that made me plunge I thought then, as tens of It was my will You may send me "Power of Will" at your risk. Probably into advertising instead of going slowly. I agree to remit $3.50 or remail the book to you thousands think today, who've heard and And finally, it was my will power that made in five days. read about this great book-that will- me say to the public-"Send No Money- power was some myth, or impractical Read Power of Will 5 days free. Pay me if Name you decide to keep it -Send it back if you thing for dreamers. don't want it." Address You see-I hadn't analyzed the lives That was a new sort of proposition to most of the world's greatest men then, and people. They had nothing to lose -and a lot City

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1240 ELECTRICAL EXPERIMENTER April, 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 experience 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. lmiNiti The N. Y. E. S. gives a special Automobile Ignition Course as an t.:í::: ¡L advanced training for Auto Mechanics, Garage Men and Car Owners. ;riata/1110 Ind= The course -s-ea®inn liaisee covers completely all Systems of Ignition, Starters, Lighting and other electrical equipment on automobiles, motor boats, airplanes, etc. Let us explain our complete courses to you in person. If you MPr w im as VW IM na aa can't call, send now for 64 -page book -it's FREE to you. New York Electrical School 1 29 W. 17th St., New York, N. Y. , Please send FREE and without obligation to 'me your 64 -page book. 1 New York NAME , STREET 1 Electrical School 1 CITY STATE 29 West 17th Street, New York You benefit by mentioning the "Electrical 40r enter" when writing to advertisers. AoIIIIUiiO,

t}1.- " -

1111 ;//i1i1111 ::1i;' ELECTR.ICAI. _. :.: EXPERIMENTER %ii /SiF 1_.,n. -4i \Y . H.GERNSBACK - EDITOR IIIIIIIIIIIIIIIIIIIIIIIIIIÌIIIIIIIÌIIIIIIIIIIIIÌIÌIIIIIIIIIIIIIIIIIIIIIÌiIL' H.W. SECOR -ASSOCIATE EDITOR /112 :IIIIIIIIIUIIIIIIIIIIIIIIIIIIIIIIIA nII11111111I11111111111111IIIIII

Vol. VII. Whole No. 84 April, 1920 No. 12 ectrIlo e ro he Sun FROM time to time we hear of new menting in the wilds and barrenness of power, particularly in the southern part of schemes devised by inventors for an Arizona desert, where sandstorms, the United States and other more tropical harnessing the tremendous energy cloudbursts, thirst and poisonous reptiles parts of the world, experience has shown shot earthward every minute of our all combined to threaten their very exist- that the sun's heat will cause the tempera- lives by "Old Sol." An American ence. All these experiences are interest- ture of the water to increase to about 150 scientist, Mr. Henry E. Willsie, has re- ingly toldfin an absorbing novel written by degrees. The heated water passes into a

COILS FILLED WITH SULPHUR DIOXIDE VAPORIZED BY HEATED ENGINE RUN WATER LET IN AND CIRCULATED EXHAUST BY VAPORIZED FROM SULPHUR FROM STORAGE TANK TO VAPOR- ENGINE DIOXIDE IZER THROUGH PUMP BACKUP TO THE GLASS FRAME

1:1:77k

HEATED WATER PASSES DOWN INTO COLi`' STORAGE TANK HOT. WATER HOT/ WATER WATER PIPE SAND LINItiG WATER FRAME . TURNED TO FACE -"It, THE SUN_ DOUBLE THICK GLASS' OVERS RUNNING WATER r WATER PUMPED TOBE RE-HEATED ,,' CONDENSER FOR SULPHUR DIOXIDE

WATER PASSES TO PUMP AND ON UP AGAIN TO FRAME SULPHUR 15 CONDENSED FCR' HOT WATER CAN BE D'r"W.10 ' PASSINGAROUND COLD PUMP FORCIN STORED AND TURNED WATER PIPES-GOING BACK UP WATER FROM INTO ENGINE AT ANY TO VAPORIZER TO VAPORIZER REGULATED TIME BY CRANK SUN FRAME

Copyright- 1920-by E. P. Co. The Latest Sun -Power Electric Plant. By Following the Pipe Lines Conveying the Sun-Heated Water to the Sulfur Dioxid Boiler, and the Course Taken by the Sulfur Dioxid Steam Thru the Engine and Condenser, Thence Back to the Boller Once More, a Clear Idea Is Had of Just How This "Free Energy" Power Plant Works.

cently proposed a new form of Solar Mrs. Honoré Willsie, entitled "The Forbid- sulfur dioxid boiler, and eventually this Power Plant, which comprises a number of den Trail." water returns to the glass heating tanks very interesting and radical features which Coming back once more to the scientific or planes exposed to the sun's rays. ti would seem to promise a successful future side of Mr. Willsie's interesting invention, Where a large plant of this type is prop- for it. Not only is Mr. Willsie a scien- which is shown in the accompanying illus- erly laid out, the mirrors or glass -covered tific theoretician, but also a man of prac- tration in one of its applications, we learn tanks in which the water or liquid is heated tical deeds, and to this end he built, some that the underlying principle is the drawing by the sun's rays may be arranged in a years ago, a solar light and power plant of the heat from the sun's rays into a fixt position, or also they may be designed on a small scale out in Arizona. The de- moving sheet of water, which passes up so as to swing from east to west with the velopment of this plant nearly caused Mr. and down thru a series of zigzag passage - sun, so as to keep the rays perpendicular Willsie and his wife their lives during their wa s, under a double thickness of glass. to the surface at all ,hours of the day. many exciting adventures while experi- Wg the sun has considerable thermal (Continued on page 1310) 1241 1242 ELECTRICAL EXPERIMENTER April, 1920 Th© mUll.e.

Close -Up View of the Battle Tracer Head, ThruMotor Which the Graduated Ene- my Arm Passes. This Connects With the Vari- ous Range Find- ing and Spotting Apparatus on the Vessel.

mwuummmmuuwmmiiiuliiiiiis emmuumml Diagram Show- ing How Range Is Computed Directly from The Sperry "Battle Tracer" Complete, and Also Revolution Converter "Battle Tracer" and Auxiliary Range Plottings So Transmitter. The "Battle Tracer" Records the That Guns Can Course Followed by their Own as Well as the Enemy Ship. E is the Be Aimed Ahead amoommm Enemy Arm Tracer and R, the Range Predictor. of Time, to Hit aaem, acak the Enemy Ship, by "Prediction." ca.-xae.wrya,

ec ES, Captain, she was traveling at arm extending from the instrument proper, parallel arms which allow free movement 18 knots; we were slowly closing called the enemy arm, keeps track at all in any horizontal plane, at the same time, in on her, and when 14 miles away times of the enemy's movements. In this however, preventing the Tracer from turn- we opened fire." way, regardless of what our own ship's ing on its axis. This allows the outer dial "The shells from the very first speed may be or what the enemy's speed (A) of the Tracer to be kept in one posi- salvo struck her squarely amidship and may be, prediction of its probable location, tion continually with reference to the table. blew her super- structure. off -." Thus allowing sufficient time for the gunners to (Accompanying letters refer to close -up continued the gunnery officer's report of change their range, can be made with review of Battle Tracer dials.) the Naval engagement just completed in markable accuracy and the guns can be This dial of which we have just spoken, which the very first shots found the enemy fired so that very few shots will miss the is one of the three dials which perform and silenced their guns before they had a target for which they were intended. varied functions. As will be noted, the chance to reply. "Suppose the enemy zig- zags," you will outer dial is graduated to 360 degrees and It is truly remarkable to think that not say. "Isn't the art of shelling more a mat- is held on the table so that zero of the even a "finder" shot had been fired. In ter of mere guess work than of accuracy ?" dial is north on the chart and is always at this case there was no need of firing the No, dear reader, no ! You must remem- the upper edge of the table, altho capable guns and wasting the big shells in order to ber that a ship eight to nine hundred feet of movement in any way except the turning get a "bead" on the fugitive vessel. long traveling at 20 knots, or perhaps, even movement. The vessel's range was computed to ab- more,, cannot steer and squirm away with Just inside of this dial and operating in solute accuracy and predetermined in time the same ease as an automobile. juxtaposition with it, is another dial (B) for the guns to be set and fired. All this It is not a question of a few seconds, but similarly graduated but movable. This dial computation with the aid of the device here minutes elapse before one of these large is controlled from the gyro- compass by one mentioned required but 19 seconds, reduc- floating fortresses can be turned complete- of the four motors inside the Battle ing thereby, past calculations several hun- ly in their course, particularly in view of Tracer head. dred per cent. the terrific speeds at which they move. A pointer coming from the center of the What is this remarkable equipment, you Hence, when a computation is made via the Tracer head extends to the edge of this will ask. Essentially, it consists of a num- tracer, and guns can be elevated within dial and the outline of a ship with its how ber of devices all working in conjunction nineteen seconds, taking the corrected find- at zero is also engraved upon it. This with each other. The most important of ings as data to work from; it then gives the pointer (D) which we have just spoken of which, perhaps, is the Battle Tracer, as it is enemy very little opportunity to change a is connected to the enemy arm and operates called. predicted and predetermined range or bear - in conjunction with it, being moved by The object of the invention, which has ing. another motor connected to the Target proven itself to be of great practical use, Essentially, the apparatus consists of a Bearing Transmitters. Both the pointer is to provide a means whereby the course of cylindrical box about 7 inches in diameter and the enemy arm are capable of complete our own ship is plotted automatically on a and 5% inches deep, containing four motors, revolution. This movable dial (B) is table similar to the table used for plot- and necessary gearing. It is mounted upon mounted upon a movable post, to the bot- ting navigation courses. In addition, an a tracer table and guided by a system of (Continued on page 1332) April, 1920 ELECTRICAL EXPERIMENTER 1243 1244 ELECTRICAL EXPERIMENTER April, 1920 etected. 0 et ..' way you do not knot perhaps, or electric galvanometer or magnetic needle sensitive thermopile for this work, and this least may not have stopt to think instrument of the D'Arsonval type. is built in an evacuated glass tube. On this about it, one of Uncle Sam's mili- Remarkable and uncanny as it may seem, measuring instrument are registered infini- tary experts can spot you in the it was actually found possible with this tesimal fluctuations of temperature. r- dark, and tell in what direction you sensitive apparatus to detect the presence A ray of light may have started ten are moving -and at a distance of 600 feet - of a man at a distance of 600 feet or over years ago from some distant star, and all due to the fact that your body radiates one -eighth of a mile away, which gave may have spent all of these ten years HEAT ! Not very much, it is true -but plenty of time in most cases to organize hurtling earthward -bound thru space at a still enough to affect a sensitive electric a counter -attacking party, or extra guard. speed so astounding that it could girdle thermopile of the type shown in the ac- This device proved very useful for de- the globe in far less time than it takes to companying illustration. tecting hostile raiding parties creeping to- blink an eye -and yet when it falls upon A recent issue of the Physical Review wards the trenches in the darkness of the bolometers at the Bureau of Standards contains a summary of a paper read by night, and helped in many cases to capture they will tell the observer how much heat Mr. S. O. Hofman at the Washington some badly wanted enemy prisoners for the that ray brought with it from the star to meeting of the American Physical Society purpose of questioning by the intelligence the earth! on this extremely interesting subject. In officers, especially when an attack was As Silvanus Thompson points out, one trench warfare operations on the Western about to be made by the Allied troops. of the most remarkable instruments of this front, maneuvers took place mainly in the One of the accompanying illustrations type is the radio-micrometer devised by night time, as any movement during the shows an effective and sensitive form of Vernon Boys. On this instrument a loop day quickly attracted hostile rifle and ar- thermopile. The minute electric current of fine silver wire is suspended by a quartz tillery fire. generated at the juncture of two dissimi- fiber between the poles of a magnet, and An attempt was made, therefore, to de- lar metals such as copper and iron, or anti- this loop of silver wire has its circuit closed tect the presence of men moving in "No- mony and bismuth, when heated by the im- at its lówer end by a piece of antimony and Man's- Land" at night by recording or in- pinging of a heat ray upon the juncture, a piece of bismuth (or alloys of these dicating the heat radiated from their will cause a deflection on a sensitive gal- metals) soldered to a minute disc of copper bodies. The receiver utilized a delicate vanometer connected to the opposite termi- foil. A rise of temperature in the copper heat -actuated instrument or heat indicator nals of the thermopile. foil, even so small as one -millionth of a for this purpose, comprising an electric Altho it is but little known, thermopiles heat degree, will generate an electric cur- thermopile placed or mounted on the focus so sensitive that they will record the heat rent in the loop and give a deflection over of a 14 -inch parabolic mirror. This ther- radiated by distant stars have been devised one division of the scale on the instrument. mopile, which generates a very minute yet and regularly employed in astromony work With a heat detecting instrument of this measurable electric current whenever a heat by those engaged in this work. type the radiant heat of a candle can be ray, even tho ever so slight, impinges on Dr. W. W. Coblentz, of the U. S. Bureau detected at a distance of two miles, as it, is connected to an extremely sensitive of Standards, has devised an extremely Silvanus Thompson shows.

VERNON Bel RADIO MICROMETER DETECTS 1A000000 DEGREE OF HEAT HEAT FROM PARABOLIC ÇLAMP MIRROR SILVER I s BODY OF WIRE /OLDIEARTDETECTED THERMOPILE LOOP FT - -REFLECTED LIGHT ----600 - -- '`,,BEAM INDICATES --,DEGREE

ANTIMONY AND BISMUTH STRIPS ABI- METALLI JUNCTURE

OF `CA p R `le, SURCE

PARABOLIC REFLECTOR! A',ID THERMOPILE/ FJ4 DETECTING ENEMY HEAT RADIATE!' `ROM tI" BORIE!

Imagine That You are a Soldier In the Dark At Night, and That You are Attempting That to Raid the Enemy Trench. Likewise, Imagine You are At a Distance of Nearly One -quarter of a Mlle from Said Trench. If It Is Pitch Dark, You Will Feel Very Confident in the Dark, That You Can Sneak Up On the -Enemy Without Exciting the Least Suspicion On His Part, -But Foiled Again! -for It Now Develops, That the Electrical Experts of the Allied Military Engineers Had Developed and Utilized Thermopi;,,, Which Will Detect a Super -sensitive Electric the Heat Radiated from the Human Body, At a Distance of from 600 to 1,000 Feet, and Many a Dead German Soldier Would Tell You the Answer, If He Could! April, 1920 ELECTRICAL EXPERIMENTER 1245

GUARD CONTROLS INTERLOCKING CIRCUIT THIS ONE ALL DOORS ON TRAIN CUTS OFF POWER UNTIL ALL DOORS ARE i CLOSED CAR 3 11 CAR4 CAR 'I

Ib LIGHT FLASHES AS LONG AS ANY DOOR IS OPEN DOOR DOOR i MOTOR MAN'S CAB OPEN CLOSED CAR MOTOR ONTROLLER

TO COMP. AIR 'OPEN"AND"CLOSE" SUPPLY - UTTONS

3RD RAIL TO, SUCCEEDING COUPLING ..Cr AIR CYLINDER ELECTRIC CARS' CARS TRACK TO STORAGE CLOSING BATTERY DOOR

ßìI -S MAN HAS COMPLETE CONTROL OF ALL DOORS ON TRAIN NOW BEING OPERAT- ED IN THE N.Y. SUBWAY

(Ally dôht- ia2u -by i. P. w. Now Being Tried Out in Actual Practise in the New York One Man Controls All the Doors on This New Semi -Automatic Subway Train Electric Control Buttons, the Guard Stationed at the Center of the Train Can, by Pushing the Proper Subway. As the Diagram Shows, and Closing the Successive Car Doors. The Motorman Can Start Cause Electro- Magnets to Control the Comprest Air Mechanism Open the r a n Ali g a 0 Sulawmy ® matic train, so that he can command a view into a subway is v ery ingenious. Everyone living in the TRAIN comes dashing of both sides, by peeking out between the station, stops, discharges its passen- greater metropolis knows that the terminals have constantly sufficient cars. At his right and left side are a series gers and allows others to enter. of the subway electrically, in this guards to successfully jam in all the people of push buttons for controlling There is nothing unnatural all the comprest air operated doors either , ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, "train" of events, as hundreds of 1111111.11,111111,111111111111111111111111111111111111111111111111,,,,,,,1,11,,,,,,,, of the train. When and out of the to the fore or aft parts trains come tearing in he presses a button, a series of solenoids stations in New York's subways every day from the N tfice to Renders automatically actuate the valves, allowing in the year. You go to ascertain for the escape of comprest air from the guard where the nearest station to some- In view of the fact that we are still the doors. The door to the end of the car, cylinders operating where is, and travel - handicapped due to the recent print- is released and flies back, allowing the but no guard in sight ! With a shrug of ers' strike, we have as yet not been discharged. thought "Hmm- passengers of the train to be your shoulders and the able to catch up with our schedule. When other passengers have entered, he mm-m! Perhaps he is down the next car We would therefore ask our readers shuts all the his comrade," you travel releases one button which playing cards with to be patient and not write us about doors, from his position, up to the position thru another coach but still no guard, and the lateness of the issue for the next He then until you of the motorman in the first car. so on down the 10 car train three months. actuates the button for performing the same wonder whether you are paying for a ride With the June issue we expect to rear. and then, last! function in the doors to the or walking the distance, -at catch up again with our regular The instant all the doors are closed, an a guard!! -right in the middle of the train. schedule. In other words, the June motorman to that it takes exactly automatic control allows the After finding out issue will be out about May 25th. throw his controller into the starting posi- six blocks to the left and two to the north, Several other publishers found it before in the opposite tion which could n6t have been done with a couple of turns necessary to skip an issue in order to Likewise the signal light still lit thrown in, to get to the desired this. direction come up to date, but we prefer not to while the door is open, is turned off auto- place, you stick around awhile, so to speak, do this. We hope our readers will no longer flashes one guard matically, and the light in order to find out why but understand and bear with us until we the motorman, and interfering is train. Cutting down ex- up toward in the entire are back to our former schedule in this way, with his control. penses? Rather. Here in the middle car, again. instantly placed Guard" -has Any of the doors may be his Imperial Majesty -"the PUBLISHERS. position, just the same entire train and can aim THE into an inoperative control of the as is being done at the present time, and the doors so that they will just miss you 11,11111111111111111111111111111IIIIIIII1111111111111M.111111.1111111111.1. feet ,,,,,,,n,,,,,,,,n,,niiisituumni,1 very little change in the old cars, is neces- by a hair even tho he is two -hundred adopting the new system. away from the door you enter. a train will hold and shut the doors after sary for them, so that they won't fall out again! Storage batteries are used to actuate all In other words, by the press of a button, Such apparatus, if close or open Hence there is no necessity of having as the electrical controls. all doors on all cars either put into universal use on all trains, would at his volition. And months of experience many guards on the train proper as the is now employing. dispense with from 12 to 15 guards per has taught him exactly when to release the company abler service perhaps, up" every- For this reason, they have stationed a train, who could do doors so that they will "clean the platforms of the subway stations. thing in sight. The method of operation guard in the center of this new semi-auto- on 1246 ELECTRICAL EXPERIMENTER April, 1920 nachfing YilarcA Z©W F you have ever planted flowers or vegetables and watched them grow Remarkably Sensitive One of the chief features and applications from day to day, of such an instrument as this, as pointed and from week to Instrument Devised out week, you have undoubtedly been by Prof. Bose, is the much shorter strongly imprest with the remarkable by Sir Jagadis Bose time that it would now require to obtain a changes which sometimes definite knowledge of the growth of a cer- occur in a single of India tain plant night in plant growth. But -did you ever under specific soil and climatic notice the change conditions. Instead of watching a whole in growth of a plant or season flower in the course of an hour, or a minute, movements of the plant the crescograph to learn if a certain plant will grow or a second? Quite possibly not-but if actually gives. well in a given soil, and in a given climate, you are interested this test can now be carried out in a few in the close laboratory Recently a large audience seated in the study of plant growth, then it days or weeks. The accompanying graphic is possible council chamber of the India Office, in Lon- curves show today to make readily visible the minute don, England, some of the effects of electric watched the growth of a shocks and poisons on plant growth. growth of plant life, even over such short plant and the effects of various stimulants periods of time as one one -hundredth of a upon it, as recorded upon HOW FAST DO PLANTS second. the large screen GROW? on the wall. This was at a lecture given by Altho you probably While there are a number of very inter- Prof. Bose. Either think a plant grows sunlight or else a beam at a fairly rapid rate, even tho you cannot

ELECTRIC BEAM LAMP

BALANCED LEVERS _y

M1 REFLECTED AND GREATLY MAGNIFIED....--.. LIGHT BEAM

MIRRORS KNIFE EDGES

STRING .4,-OPTIONAL BEAM FOR RECORDING

CLAMP ADJUSTABLE M3 MIRROR

CLOCK WORK DRIVING DRUM

ADJUSTABLE SIPHON

RECORD OF PLANT GROWTH MAY BE MADE ON REVOLVING CYLINDER

PLANT UNDER STUDY

0.pyright- i929 -by E. P. The Bose "Balanced Crescograph" for Recording, Studying Co. Instrument Magnifies the and Demonstrating the Growth of Plants. This Remarkably Movement of a Plant While Growing, Up to 100 Sensitive Witnest the Million Times. In London, Recently, a Whole Audience Action of Plants as Reflected on a Large Lecture Screen. esting and useful devices available in col- of light from a small lege laboratories incandescent lamp notice it in a period of, say, five minutes or for the study of plant may be used in the crescograph, and growth, as well as the action and reaction this even an hour, yet the plant really grows light beam is reflected thru a series of mir- much more slowly than you perhaps of plants, due to the application of heat and rors in the manner evident im- cold, as well as from the ac- agine. various chemicals and elec- companying illustration, so that by the time tric shocks administered at different time it reaches the screen the The little snail, whose slowness is pro- intervals, relative movement verbial, moves et cetera, one of the most accurate between the mirror and the focal spot of 6.000 times faster than the plant grows ! and remarkable instruments ever devised the impinging light beam is very markedly Plants grow at an average rate for this study is the one recently used by magni fíed. of one one -hundred thousandth part of an Sir Jagadis Chandra Bose, hailed as the inch per second, or, in other words, plants In the case of the lecture just cited, a add about most eminent man of science that modern magnification one inch to their stature in eleven India has produced, and which device is of from 1.000,000 to 100,000; days. A few years ago you would have known as the 000 times was achieved. This is tanta- thought it impossible to Crescograph. This instrument mount to magnifying actually see the is shown in the illustration on our front the highest powers of plant grow before your eyes, but now, the microscope 100,000 times. The room thanks to Dr. cover, as well as in one of the accompany- being Bose's remarkable researches, ing drawings by our artist. darkened, a mysterious hook of light you can readily do this with the cresco- past swiftly over the screen. This showed graph. the actual growth of the plant HOW THE "CRESCOGRAPH" MAKES PLANT as projected At a recent London lecture, Sir Jagadis GROWTH VISIBLE. from the mirror of the crescograph, magnified many hundred thousand times. The Bose took a cyclamen leaf and attached it Before going into the details of the cres- lecturer pointed out that to the crescograph. The mirror at once re- cograph this hook of light or the auxanometer, both of which illustrated the effect of electricity upon the flected a spot of light on the wall screen, show the growth of plants in a vivid man- plant-too great power having the opposite and this spot moved ner, it will interesting at the rate of ten feet be to note what a effect to the stimulation afforded by a rea- in twelve seconds, notwithstanding really wonderful magnification of minute sonable the fact amount. that the plant was growing only at the EXPERIMENTER 1247 April, 1920 ELECTRICAL esting results in actual rate of 1/100, - watching the growth 000th part of an inch of plants. per second. There are two Plants resemble forms of the cresco- animals very much graph, the simple in their daily lives, crescograph and the and Dr. Bose's re- balanced type. The searches have shown AUXANOMETER larger illustration the presence of heart herewith shows the spasms, details of the bal- beats, death STUDENT'S APPARATUS definite and positive anced crescograph FOR STUDYING PLANT reactions to various LEVER devised by Prof. GROWTH SCALE forms of stimuli, to BALANCE Bose. The principle anesthetics, poisons, WEIGHT involved in the etc. All of this work COUNTER WEIGHT method of balance shows, according to TO KEEP THE STRING consists in making Prof. Bose, that STRING TAUT TO PLANT the spot of light, plants, like human BEING which is moving in beings, do have a TESTED response to growth, nervous system. It become stationary is reported that this by subjecting it to a great savant of In- compensating move- dian culture and sci- ment. ence has actually Let us suppose shown that plants the average rate of can and do feel the growth to be 12 effect of an etheric mm. per hour. This wave message, or a will cause an excur- Marconigram. as sion of the moving they pass over the spot of light from, earth. This proves say, left to right, that the plant is thru 1,200 mm. by more sensitive in its the end of the hour; case the mag- nervous response UNDER STUDY in that than the human PLANT nification is 1,000. body, which we usu- Had the growth ally are wont to Copyright- 1920 -by E. P. Co. been uniform this of as the most Require- would have meant a think " -a Simple Instrument Well Adapted to Students' structure Here's the "Auxanometer of the Plant Are Magnified of 20 marvelous in Studying Plant Gr movement ever created. Peo- ments b the LeverlighttMovements mm. per minute. But ple have never yet, if not uniform the so far as we know, rate might some- to "feel" times been able The reader can readily devise a simple times have risen above, and at other a wireless signal or wave passing thru them, constructed fallen below, this average. If we now sub- of specially sensitive appa- form of magnifying apparatus but by means some pieces of aluminum wire and ject the spot of light to a uniform compen- ratus connected to a plant Prof. Bose has from sating movement, such as by itself would the effect possibly a balance wheel, with its support- shown that the plant really feels an old alarm clock have made it move from right to left of the wave and will interpret this ing pivots cut from of the radio whereby he can obtain some inter- recording surface to the extent of 1,200 min. effect under the proper conditions. frame, by the end of the hour, we shall find that, One of the interesting stories of Prof. being acted on by these two opposite move- Bose's interesting work relates how he stud- ments of growth and compensation, the ied a certain tree in India which had never spot will remain approximately on a single been transplanted successfully. He rea- base line of compensation. The fluctua- soned that the tree died when transplanted tions, or variations, which have occurred because of the severe shock it received in this average rate of growth will, how- when it was dug from the ground, so he ever, be recorded as deviations to one side followed up this deduction by having a tree or other of this mean neutral line. Thus to an anesthetic, in the same deviation subjected o io it will be seen that the slightest manner that the modern surgeon causes his :5' io' from a uniform rate of growth will be patient to become unconscious in prepara- fig. found displayed by the record of the mov- tion for a surgical operation. Strange to ing spot of light. relate, the tree manifested the same charac- We are further enabled from our knowl- teristics as a person under an anesthetic, edge of the speed of the recording drum and it was successfully transplanted while and the balancing rate, and from an inspec- under the effect of the same. The tree tion of the curve itself, to determine not continued to thrive. only the periodicities, but also the absolute WORKS. fig. 2 value of the rate of variation of growth HOW THE CRESCOGRAPH at any given moment. Several different forms of magnifying The compensating movement referred to instruments for studying plant growth have by other is effected by means of a simple hydraulic been devised by Prof. Bose, and device. The spot of light from the optical workers in this field of science. The stand- is shown level falls upon a mirror attached to a sec- ard form of Bose's crescograph or to a rotating wheel. The arm and in picture herewith. ond lever, diagrammatically iá' 4o' JO .áo' ó /0' of the lever, or a thread which is past The student will find the simple form of S known fig. 4 i9 around the wheel, is attached to a float on plant growth measuring instrument, the surface of a cylinder of water. Water as the auxanometer, illustrated herewith, and is escaping from this cylinder, by means of quite within his mechanical possibilities, at a rate which can many different ways. A Fig. 1. Fatigue Under Long -Continued Stim- a syphon arrangement, it can be made up in ulation in the Contracile Response of Plants. be adjusted with the greatest nicety. The smoked glass caused to travel slowly past (a) Stimulation by Tetanizing Electric descend at any will re- Stimulation by Rapidly Succeed- float can be thus made to the needle of such an instrument Shocks; (b) is desired, this descent produc- place. ing Thermal Shocks. speed that cord the changes taking Fig. 2. Effect In Acceleration of Rate of ing a rotation of the second lever or of the One principle, and in fact the underlying Growth of Seedling of "Oryza Sativa" of to Continuous Line wheel. feature of all these instruments, appears Current Thru the Soil. The mirrors, of which one movement is magni- Shows Effect During Passage of Current We have then two be the fact that a slight Left to Right ( -), the growth - by the well Thru the Soll (1) from is rotated in one direction, by fied into a larger movement, and (2) from Right to Left (,-). Dotted movement of the plant, and the second in law of levers -thus if you have a Line Shows Effect of Cessation of Current. known Electrical Re- in the opposite direction, by the descent of lever 100 inches long, and place a fulcrum Fig. 3. Additive Effect in then any sponse of Plants. (a) A Single Stimulus of the float. A spot of light reflected on the at one inch from a given end, 3 Degrees Vibration Produced Little or No or one Rapid- two mirrors will thus remain stationary movement at the end of the shorter Effect, but the Same Stimulus When precise balance is effected by of the lever will cause a cor- ly Superposed Thirty Times Produced the when the inch length Large Effect (b). Leaf Stalk of "Turnip." proper regulation of the escape 6f water responding and greatly magnified motion of by Poison. longer limb, Fig. 4. Death of Plant from the cylinder (see our figure herewith). this lever at the free end of the Fig. 5. Death, and Arrest of Pulsation, in (Continued on page 1318) which will be 99 times the initial movement. Leaflet of "Desmodium," by Electric Shock. 1248 ELECTRICAL EXPERIMENTER April, 1920

y WIlHFIIE!D 5EC,®R

IN the past ten years, and particularly in the last twelvemonth, there has been ShmIlfl We Ever F3e or other means, with a strange neighbor evidenced a great deal of activity on Abile 4® Ságai-naIl so distant as the Martians, Dr. Steinmetz the part of scientists in all parts of the Mars should certainly be fully qualified. world, on the subject of communicating H1t4eflIlggenBIly Dr. Steinmetz, in a recent statement, with Mars, or possibly ? said Venus. The present that wireless communication with Mars is not at all improbable, and he suggested that signals might be transmitted by radio from a gigantic wireless plant on the Earth, which would be charged with all the electric power generated in the United States. This could be accomplished for the tidy little sum of about one billion dollars, according to Dr. Steinmetz, and would require steel towers at least 1,000 feet in height, in order to transmit radio messages or signals to the planet Mars,--which never comes any nearer the Earth than 35,000,000 miles, and at certain periods is 230,000,000 miles away. After mentioning the fact that we might accomplish the interpretation, after several years' recording, of the stray wireless signals mentioned by Marconi and Tesla as being picked up in their powerful radio stations, he goes on to say,-"If Mars was trying to communicate with this world, it is doubtful if it would ever be possible to decipher the code, but it would be some satisfaction to know that one planet could send messages to the other, and that intelligent beings were inhabiting the planet from which these messages came. We know enough about Mars to assume that there are KEYBOARD SWITCHES inhabitants there," said Dr. Steinmetz, "and ENABLING ELECTRIC SIGN as it is a much older planet than ours, its rIGLIRES TO BE CHANGED inhabitants AS DESIRED ought to be more advanced in scientific and educational investigations." But -"It is doubtful if it would ever be possible to decipher the Fig. 7. One Writer on the Subject of Inter -Mars Communication code " -read Upon Thousands Has Suggested That We Place Lamps, Thousadds that line over of Them, Over a Large Territory -as Big as the State !-for it means a whole book- Quick-Acting Shutters. of Illinois -These Lamps To Be Fitted with Electrically Operated. The Lamps Are Also To Be ful when you start to really by Depressing Connected to Suitable Keyboards so That think about it. a Given Pattern of Keys, Any Design -D Such as a "Map" of the United States, "UN- I.TE S- T- A- T -E -B" !laminated Can Be Flashed Out of with the Letters Desired Letter the Entire Lamp Field as Here Shown, etc. A SIMPLE EARTH -MARS CODE or Picture Could Be Flashed on This Multiple Lamp Bank, Any FOR as Becomes Evident. NUMERICS. discussion has nothing to do with the One of astronomical the latest Martian communication There is, perhaps, no use of talking about facts of the case, for these are converts is Dr. Charles Proteus communicating already well known, -at least so Steinmetz, with Mars, or as we said far as the probably the world's greatest electrical en- before, with a people distance between the Earth and Mars is gineer today, and of whom we know concerned, and one of our foremost absolutely nothing, but for the other heavenly bodies. mathematicians. If anyone should present we The be able will consider that they are duly existing, main thing that we do not know to conceive'of a scheme for opening up con- about Mars, is versation and that they are, as some of our leading whether or not it is in- by wireless telephone or telegraph, scientists habited, but we will leave all of the vast and astronomers have argued, and profound theories on the possibility of Mars' inhabitation, to the astronomers and others who are capable of investigating these facts. So far as we are concerned in the present instance, we will assume that there is such a being as a "Martian ". Next, the all - important and preponderant phase of the Mars' inhabitation theory is-how, and in what way could we start picking up conversation or communication with our distant neighbors, intelligently. It seems quite evident, that once we have outlined and developed the proper method of procedure to start transmitting and possibly interpreting the Martian signals, as well as making sure that our method is correct, that the Martian may, with his supposedly far greater intellectual development, (owing to the greater age of Mars as compared with the Earth,) understand what we are trying to say to him. It is nothing short of startling to read some of the newspaper details that come from all parts of the world, suggesting the "simple schemes" whereby we can open Fig. IA Shows the Gigantic up Man, of Size Compared to a communication with a people of whom we the New Sperry HighPower Searchlight, know absolutely nothing TheinFan Arrangementngement of Light about. Think of by Beams Was Formed it ! Aside from the fact that we have to the Searchlight, Stronger ache Divided BeamrsBeing Far doubt their very existence, Than That Flashed from we do not have High -Power Searchlight the Average the slightest conception of what they look of the Ordinary Type. like, nor what their language may be! April, 1920 ELECTRICAL EXPERIMENTER 1249

11IIIIIIIIIIIIIIIIIIIIIIIIN

Fig. I. The Latest Proposal as to How to Signal the Inhabitants of Mars Is That of Mr. Elmer G. Sperry, Inventor of the World's Most Powerful Electric Searchlight, Shown at Fig. I -A. Mr. Sperry Proposes That We Employ a Bat- tery of 200 of His 1,250,000.000 C.P. Searchlights In One Gigantic Bank, so as to Concentrate Their r Rays in One Powerful Beam of Light. It Is Calculated That the Martians, If Such There Be, Can- not Miss This Blinding Flash of Light, Which Would Appear to BATTERY Them as a Star of the 7th Magni- GIANT tude, Which Is Easily Picked Up OF 200 SPERRY by Our Earthly Telescopes. This SEARCHLIG-ITS Beam of Light, Totaling 250,000,- GIVING I,25fG000OC4- 000,000 Candle- Power, Would Rival C.R FAN OR IrOTAL the Sun Itself. BEAM OF 25013ILLIDN C. P. Pt?Itk`TIFLLi MARTIAN -WAR D 1111 111 II I1810lMERIEMMI 1111 111111111

thousands of years in advance of us when it comes down to scientific matters including the languages.

Probably they have but - one language on the order of our rapidly growing universal language -Espe- ranto. L EIFFEL T7WEn y All well and good, but - WOO FT. HIGH. without wasting any more time conjecturing on the ways and means of interplanetary communication, i

let us start with the fun- - damentals of the understanding between any two Earthly human beings. To ., do this, as one professor of languages recently suggested to the writer, we certainly will have to step back to the period when ° we were little children. THFV THE MART EE,i Go straight back to the C OPEITHE SPERRY days of the kindergarten, ELECTRIC b:ARCH, I LIGHT FLASH and then we are ready to - - WOULD APPEAR THE S1ZETF A start learning the real 7," MAGNITUDE fundamentals of com- STAR,WH -CH 13 munication and under- SEEN READILY ,1-. 2 BY -eS IELES' standing via the language GOP ES route between humans. But before going further, we might take a glance at Fig. 2, which shows the Copyright,-1920 -by E. P. Co. simplest scheme for teaching or endeavoring to communicate to an- times beyond number, that this is a very It take;, but a little reflection to see that, other person, the elements of numeric com- good and plausible way to start communi- while presumably and with average intelli- putation. cating with the Martians, and not only this, gence no greater than ours, in a short time but they often carry this idea to the point a person who doesn't know our language Fig. 2 shows that two dots, plus two dots, at all, should be able to perceive if shown equal four dots. Little children are often where it is claimed that eventually lan- dots, explaining the languages a blackboard with this arrangement of taught in this way by several different guages or codes that we were trying to impress upon him schemes, how to count. Some of our ablest may be transmitted and interpreted either the fact that two dots, plus two dots, equal scientists and astronomers have suggested by us or by the Martians. four dots. Well and good, but when it comes to communicating letters or words of a by this method, it would seem WHAT THE language t? *!. to be quite impossible, and altho the writer

I III 1111 IMI111I1111111111111111111111111 IIIIIIIIIIIII I I IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII111IIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIII1111I

FIg. 5 (Inset). You Do Not Have to Endeavor to Open Up Wireless Telephone Communication with the "Mar- tians" in Order to at Once Perceive That You Have "Started Something " -so Far as It Is Possible to "Talk." or for That Matter If It Would Ever Be Possible for You to Learn Even One Word of Martian. The Experiment FORGET THE MARTIANS! PUT A of Placing a Chinaman and a Yankee on Opposite Ends "YANK" AND A "CHINAMAN 'JN of a Telephone Line Has Been Tried for a Considerable BLACK GEOMETRICAL OPPOSITE ENDS OF ATELEPHONE Time Period, and Neither One Could Assimilate or In- TRIED; ONE DESIGN ON WHITE LINE- THIS HAS BEEN of Language, Altho They CANNOT LEARN A SINGLE WORD DESERT SAND terpret one Word Each Other's OF THE OTHERS LANGUAGE. J Talked Long and Often, Over the Telephone. Fig. 6. IF YOU DON'T BELIEVE IT -TRY IT Sir Oliver Lodge Suggests That We Build Large Geomet- rical Figures In Black oa the White Sands of the Sahara Desert, and He Believes That the Martians Will Under- stand It, as Geometry Is a Universal Study and Science.

IIVIIIIIIIIIIIIIIIIIffimmInIIVIImIsommIIIIsIIImmIfinniIIIIfis1Inm'IGII

has discust this scheme with several experts SIR OLIVER LODGES SUGGEETION on languages, they have not been able to FOR MARTIAN SIGNALING, BY 1.5ING ADJUSTABLE think of a single method whereby it could GEOMETRICAL DESIGNS DESIGN DEVICE be carried out. So we go back once more to the little children in the kindergarten class. We will 1250 ELECTRICAL EXPERIMENTER April, 1920

or stands for than the sider for one tpoment -no matter how fa- wood tie -post to which you miliar you may be with secret codes and hitch Old Dobbin - ex- ciphers-and try to think how you would cept for one potent and look this first Martian word squarely in the all- important considera- face and endeavor to understand what ob- tion, and that is -that in ject it represents! Does it represent a sea? the books from which he Does it represent a house ? -or a Martian studies or else by means horse ? -or does it mean a declaration of of the blackboard and the war between two Martian nations -and so skilled artistry of the on and so forth. Consider that the writer is a Martian and that thru your powerful Illllllllllllllillllllllllllllllllllllllllllllllllillllllllllllllllllllllllllllllllll earthly telescope some dark night you are confronted by a And Wonder of Wonders! -Here Is burst of light from Mars and upon direct- the Very High- Powered Marconi ing your telescope more minutely and accu- Radio Station at Which the Mys- rately towards terious Dots and Dashes Filtered this illuminated spot on the In from the Ether -and Further- distant planet you read in outlines of fire more These Signals Are Believed this word. There is no use of taking by the Great Marconi Himstlf to any Quite Possibly Be ''Signals of Inter- other words, for this one serves its purpose Communication" Hurled at Us Thru (Continued on page 1302) Miil:ons and Millions of Mlles of Interstellar Space, Via Wireless, by the Mart-ans. At Left We Sec the THIS IS "REAL MARTIAN" 100,000 -Meter Wave Inductance. At CAN YOU TELL WHAT Right the Wonderful Eleven -Stage THIS WORD REPRESENTS? Audion Amplifier, Magnifying the Signals 10,000,000 Fold. 2 + 2 = 4 IVIIIIIIIIIIIIIIIIIIIIIIIIIIIIIViIIIIIIIVCiIIIIIIIIIIIIIIIIIIIIIIIVIIIIIIIIII GOUKA = ? ;g.2. fig.3. teacher, he is shown a rat, or possibly he might be shown á live one in a cage, or a dead one-but in any case he does two things when he first learns the meaning of any word, RAT in this case "rat." He is first taught to pronounce fi8.4 and how to form the let- L.C. ters of the word in writ- ' ing, and then he is shown At Fig. 2 We Have the System- Commonly Advocated For eave numbers out of the question, because simultaneously in some form the object Opening Up Communication Between the Earth and Mars we cannot carry on a conversation which by Means of Signals Sent by Light, Radio, etc. This Is very the word represents. to Give the Martian to Understand That We Earthians Count Two Dots Plus Two well with a set of figures, -or at least we Some one may object at Dots as Four Dots. . It Is this point and Conjectured That in a Short will presume Time We Can Thus Inter - that this is not the case with say it is not so in every case that an object Communicate Very Nicely with Our Martian Neighbors. If You the Martians. How is a child taught the representing the, word Think, However, That Such a System as This Will is shown simul- Eventually Lead to Inter -"Language" Communication and letters of the alphabet and their final cor- taneously with the mastery of the word, Understanding, Try and Dope Out What the (Assumed) relation into words, -and again, -the mean- but the Martian Word "G- O- U -KA" Means. Fig. 3. In the Next answer is that if this is not done, Issue We Will Tell You. Fig- 4. The Most Logical ing of these words? then the teacher or the governess will have Method of Establishing Any InterLanguage Communica- tion with a Strange People, Such as the Martians, Surely When you have thoroly philosiphized on Seems to launch forth on a lengthy word- picture To Be by Means of "Wird Pictures." Such as this elemental detail of pedagogy, you at Shown Here, Flashed or Otherwise Transmitted Simul- explaining about the rat, let us say, and taneously, in Such a Manner That the Picture Can Bo. once become cognizant of the highly impor- what it looks like. Built Up. Otherwise, if the Martian Received the Letters tant fact that the little child who does not This R -A -T by Radio and Could Understand Them, but Did basic element of learning any lan- not Know What Our Animal the 'Rat" Looked He Would Like - know anything about the language he is to guage is more forcefully Have Some Tall Difficulty in Trying to Find shown at Fig. 3, Out What R -A -T be taught, cannot teil what such a simple Meant, Granting, of Course, That He where there is also shown what we shall Knew Our Alphabet -For the Chances Are That Animal word as "R-A-T" means. He can be taught call, for the sake of supposition, a real Life Is Different on Both Planets. the sounds of the letters of the alphabet so Martian word, G- O- U -K -A! Now just con- IVIIIIIIilllli!!i!!'lllllllllllllllllllllllllll!i!" as to pronounce them- "I!IIIIIII111IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIVIIIIIIIIIIIIIII< and also how to write' them -but as soon as he FILM has finished with this, DEVELOPED TO FROM DRUM RADIO RECEIVING think of asking him to P APPARATUS

1111IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIID1III' The Mysterious Stray Wireless Signals Which Have Been Re- corded by the Marconi Trans -At- lantic Station, May Have Some Meaning Which We Do Not Un- derstand as Yet. It Has Been MAGNETICALLY Suggested by One Authority That Possibly if We Have the Proper OPERATED Apparatus or Scientific Means For Interpreting These Apparently LIGHT SH UTTFÇR Meaningless Jumbles of Dots and PLAUSIBLE Dashes, That We May Cause MARTIAN WORD-PICTURE BEAM OF LIGHT Them to Produce a "Picture." WHICH MIGHT Suppose, For Example, That You BE RECORDED ONA Had a Revolving Drum Which REVOLVING DRUM RECORDING DOTS Was Moved on Its Axis and Cov- BY DOTS OR ered with a Photographic Paper INTERMITTENT RADIO SIGNALS AND DASHES ON or Film. If the incoming Radio i;' Dots and Dashes Were Recorded ROTATING ANDTRAV- on This Drum, They Might Pos 1_ II`mIv síhly Form a "Picture and a LING DRUM Word," Probably in Martian. If We Were Able to Obtain a Con- siderable Number of These Word Pictures We Could Eventually I II Figure Out What the Martian IjIgIl1, Alphabet Is. Fig. 8. BELT TO I l <<1 'lï VIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIiII IIIu ,11 MOTOR THREADED define the word "rat" - RECORDING SHAFT AND a simple three - CYLINDER letter IIIIII, combination. Now, it is MOVES THIS WAY BEARING at once evident that the child has no more idea of what R -A -T means E.E. April, 1920 ELECTRICAL EXPERIMENTER 1251 lect icity on.a anzn Seal y FRE Co KELLY HOW the Germans sealed up over the safe, and the knots were sealed and In this way the seals could be removed one a ton of official and secret papers stamped. The tape was also fastened at a time, without disturbing the impression in the safes of the Swiss Con- against the flat surface of the safe doors of the official stamp. Later the seals could sulate at New York, only to be with sealing wax and this, too, bore the be glued back to the same places from fooled by five - tmerican adven- official stamp. which they had been removed. turers, who secretly opened the wax seals Because the larger safe was the most There was still the problem of getting on the ropes and locks during the nights carefully sealed up, the visitors assumed the tape removed from the handles of the when the office was vacant proves highly that it must contain the most valuable safe doors. But the callers hit on a plan interesting reading. The tale of these five papers. They determined, therefore, to try for doing this that made the job simple. doughty knights, whose names are unknown to open that safe first of all. But even aside Instead of trying to remove the seals and to the Government to this day, is told in from the problem of working the combina- unwind the tape, they removed the little this story. These unknown workers of tion, it looked like an impossibility to open invisible cotter -pin which held the grip part Uncle Sam, who finally procured all the the doors without disturbing the tape and of each handle in place. Then the whole secret papers and handed them over to the seals. mass of tape could be slipt right over the

OFFICIAL COLORED WAX SEALS PLACED TAPE SEALED ALGt C ALONG CRACKS CRACKS OF DOOR;,

.-NE WIRE TO RE -!'-

INSULATION -FO Rh

SWITCH

HANDLE \A

Copyright- 1920 -by F. P. Co, One of the Most Absorbing Chapters of "World War" History, Which Was Actually Enacted Not on the "Battle- Front" -But 4,000 Mlles From It, in a Quiet Little Consulate Office Located in New York City, Is Here Told by the Author. The Germans, When They Left Amer.. ica, Placed Over a Ton of Valuable Papers In the Safes of the Swiss Consulate, and Plastered Up the Cracks of the Doors, and the Locks With Rope, Paper Tape, and Wax Seals Bearing the Imperial German Seal. Not to Excite Suspicion, Five Adventurous Americans Suc- ceeded Finally, Thanks to the Clever Electric Heater Here Illustrated, in Removing the Seals Without Damaging Them-Procuring All the Secret and Valuable Papers -and Then Gluing the Seals Back Into Place.

Government, hired a suite of offices in the HOW ELECTRICITY REMOVED GERMAN knob of the handle. All very simple! building where the papers were stored. SEALS UNDAMAGED. The handles showed slight blemishes First they had their lock expert fashion If these seals were noticeably marred it where the pins had been removed, but this a key to the outer door of the consular soon would be discovered that the safe had was quickly remedied simply by polishing offices, and one night they went there to been tampered with. This would prevent the abrasion in the nickel -plating and apply- look the layout over. To all appearances later visits, and furthermore, if it became ing a little nickel -plating solution. the German papers were stored in two large known that the papers were gone, part of The job of opening the safe, removing the safes, several sections of metal filing cases the value they might have in tracing Ger- contents and restoring the safe to its pre- and a steel trunk. man agents might be lost. vious condition occupied the five men from Each safe and each filing case was bound about 11 o'clock at night until toward day- The visitors saw that if they were to open dared around with rope and with red- white-and- the safe not have their afterward light. It was many days before they black tape -in much the same manner that and work return to continue their search. While the a shoe -box is tied with a piece of string at discovered they would need several in- nature of the papers in this safe was dis- a store. The knots in the tape or rope genious tools. When they returned a few appointing, the Germans, with typical Ger- were invariably covered with sealing wax nights later they were equipt with such tools man inefficiency, had left in the safe a great of a special kind not easily imitated, and and devices as were required. The most quantity of paper seals of exactly the same the wax was stamped with the official Ger- noteworthy of these was an electrical con- kind that they had used in sealing up the man seal. trivance which could be attached to one of drawers of the metal filing cases. The pos- Particular care had been given, appar- the electric light sockets near the safe. session of these seals greatly simplified the ently, to the sealing up of the larger safe. The working part of this consisted of a job of opening those drawers later on. Pieces of sealing wax, bearing the official Y- shaped instrument between the two prongs On a certain night while the Americans stamp, had been stuck at intervals all along of which was stretched a fine wire. This were at work on these files, a man, now sup- the cracks at the edges of the safe doors. wire, when heated by the electrical current, posed to have been the night watchman, Official tape had been wound back and forth could be past underneath the seals where came along and nearly stumbled upon them. between the handles of the double doors of they adhered to the flat surface of the safe. (Continued on page 1331) 1252 ELECTRICAL EXPERIMENTER April, 1920 751102E10 E MuzIlc 1140T The Deaf By Ho GEIL3HaBACK

WHEN I was sixteen I secured an series with the 6 -volt storage battery and mechanical suspension old- fashioned Pathé phonograph the primary of the carbon dia- of an induction coil such as fram must be the same as the one for the of the cylindrical record type. is used in telephone work. You know mica -diafram. In other words, the vibra- the kind that was in The writer used a regulation sound box tions of vogue years ago. Being much the phonograph needle must be in- merely by making a microphone out of it faithfully past onto the carbon diafram, terested in electricity in those days, the and substituting a carbon thought occurred diafram for the the same as is the case with the mica type. to me, the same as it mica diafram. The space between the When the connections occurred to thousands of others, namely, are correctly made back carbon and the carbon diafram is and two handles are now attached to the why not transmit the music electrically by filled out with polisht carbon grains. putting a sensitive The secondary of the induction coil, and these microphone somewhere graspt on the phonograph and thus get the music in your hands, the rhythm of the at a distance. music will be felt faithfully and with astonishing fidelity. What feel No sooner said than done. An old - we do is fashioned Hughes sound vibration translated into electrical microphone was con- impulses structed by means of three little carbon which in turn are felt physio- rods, and this miniature logically by the human nerves. It is sur- microphone was prising attached to the sound box. The micro- how well this translated music is phone was in series with communicated to thenervous system of the a battery and human being, the primary of an ordinary telephone in- and with a little practise it duction coil. The becomes possible to recognize the different music transmission was tunes excellent and phonograph music was trans- merely by the variations of the little mitted over a distance of three hundred tingling shocks. yards on my father's Different records were tried in 1917, but estate. These experi- then the ments created quite a sensation in those just United States entered into days, and my friends, all elec- the war, and the experiments came to a trical "bugs," were much elated sudden end. Recently, however, and pleased with the stunt. MICROPHONE they were taken up again with One evening I accidentally the following results. Improve- touched the two wires of the ments were made on the micro- secondary terminals of the telephone and a great many new phone coil and was quite sur- LOUD TALKER types were tried out, because the prised to get a smart and dis- original type was not entirely agreeable shock. That was in satisfactory. Later experiments, 1900. The early experiments however, proved to me that the were soon forgotten, but in 1917 type in principle was prob- 1917, while editing an article in ably the best that could be pro- this magazine, where a young" duced. From some ten or twelve man had re- discovered the an- types which were evolved by me cient experiment, I thought of then, a few are shown here. that shock, and I understood im- Many different records were mediately what that shock really tried, and it seemed to be readily was. I accordingly set to work e s t a b 1 is h t that the different and immediately built a new tunes, the different musical in- transmitter which was attached struments, as well as voices, to a Victor phonograph sound could be readily differentiated box, and which is shown in physiologically without listening at all to the music, Fig. 4. The connections are Mr. Gernsback Demonstrating the Physlophone. The Ph otograph or without shown from which it will be Shows How the Instruments Are Connected. By Means of the hearing any sound whatsoever. Double Pole Switch, the Music Is Reproduced by a Loud seen that the microphone is in Then the Switch Talker, Of course, it goes without say- Is Thrown, and Physiological Music Is Had. ing that such experiments must

IIIIIIII III IIIIIIIIIII

0 INDUCTION BATTERY COI L

MICROPHONES I¡I1,1 io,p1 i p¡ui,iil

CHAIRS

Double Barreled Music. Showing How an Audience Can Enjoy the Music Orally As Well As Physiologically. In Other Words You Hear the Music and You Feel It As Well. A Brand New Source of Enjoyment. April, 1920 ELECTRICAL EXPERIMENTER 1253

Music. Due to the Rhythm a During Tests With Totally Deaf People, They All Expressed a Great Desire to Dance by Means of Physiological Deaf Person Can Now Dance Without Any Trouble by Means of Physiological Music.

however, did not work as well, and very two transmitters were simply attached to be made with the phonograph in a different band serving part of the building with the handles so far little could be felt at the secondary end. the needle holder, the rubber In Fig. 2 is shown two transmitters, be- simply to feather the action, but the re- away that the music from the phonograph good, and the cannot be heard at all. When using the cause the writer at one time when work- sults in neither case were ing with a single transmitter on a disc original 1917 type transmitter with certain microphone type as shown in Fig. 4, the to work best sound near the phonograph is still audi- type phonograph did not receive all the im- refinements has been found ble, altho not anywhere near as loud as pulses, that is to say, only one side of the in all respects. if the original mica -diafram were used. lateral cut vibrated the diafram. What purpose is accomplisht by these For this reason the handles must be The same idea is shown in Fig. 3 where experiments? Ordinary human beings cer- located in another room so that whatever tainly do not require the translation of music leaves the phonograph cannot be musical impulses into their nervous sys- heard. I used a double -throw switch and tem, but for the deaf a vast and important a loud talker of the type commercially sold, field has been opened. Here we have a and invited visitors to first listen to the means of translating music into the ner- phonograph record by means of the loud vous system of a deaf person who has not talker. Then the switch was thrown, and the slightest conception of music. Of of course no sound was heard at all. By course, it should be understood right here grasping the handles, the visitors could that I do not mean to convey the idea that readily follow the rhythm of the record, a deaf person will actually "hear" the and right here a curious thing happens. music. What he does get, however, is the Some people, altho musically inclined, rhythm, and he certainly gets this very have trouble in following the music, while definitely as has been actually demon- others immediately recognize the different strated by tests with deaf persons upon strains and have no trouble to sing or which the writer experimented. It has whistle with this physiological music. been found that a deaf person can readily There seems to be a difference in the ner- understand the different musical pieces, and ' vous system of individuals, and some peo- can even recognize different musical in- ple can more readily translate the rhythm struments with very little practise. than others, altho not necessarily more Of course, the deaf person must learn musically inclined. Other tests were made the same as any other human being, for it paralleling the idea by using no phonograph is a well -known fact that if a person at all, but simply a microphone into which totally deaf were restored his hearing, he a person spoke. By having the experi- would not be able to understand what you menter count from one to a hundred, the said to him for some time to come. He other party at the far end could feel the would have to learn and judge the sound voice impulses and after a while man- just the same as a child. The same is the aged to "understand" the voice by physio- fEum,11 case with a totally blind person who has logical impulses. never seen daylight. Experiments made In Fig. 1 is shown another type of trans- with such people invariably prove that as mitter attacht in front of the sound box soon as the eyesight is restored, they do in the phonograph. It consists simply of not see in the sense that the normal person 4. Schematic Illustration of the Com- three transmitters connected in parallel, the Fig. on page 1320) connections being the same as usual. This, ponents of the Physiophone. (Continued 1254 ELECTRICAL EXPERIMENTER April, 1920 E,ectrco-,Meclicemi, FEcomuc] laY JJOOEPH 1ERAIY

FROM tame immemorial, people of and with more safety, blow red pepper this and foreign countries up did they ever have even the slightest effect have al- his nose, and get his sneeze cheaper than upon the individual. lowed a class of humbugs and by sniffing Such bunko devices at a $10.00 evil smell. as the magnetic hair brushes fakers to foist upon them innumer- This and combs, able cure -all devices fraud claimed, in addition, to be "cold feet" pads generating electricity due and medicines. an ozone battery, to the Not alone have these quack doctors been the electric action of action between the copper and zinc charging exorbitant prices which was due to the copper and zinc in- plates, and electric belts, not only never for worthless volved in its cured, trash, but they have also caused various construction. We would but also made themselves uncom- injuries and hardships refer the reader to several past descrip- fortable to the wearer. to those attempting tions of real ozone to manipulate or apply these worthless generators and recall Out of hundreds of claims for testimo- humbugs to his mind that even the smallest of these nials, not one cure could be authenticated "as per directions." generators In was comparatively bulky and by the use of the various devices here re- medicines, even today, the market is ferred to. full of glaring advertisements of remedies 1111111111n1111111,.1=11111111111111111111111,,,.11.1111111111111111,,,1111111111u1111111111111 In 1/111/1 order to note the effect of magnetism which formerly __ were claimed to cure any- on the human body, thing from a corn to a malignant tumor. tests were made in France (see Fig. 2), which involved the Some of these fakers and quack doctors use of gigantic electro-magnets have ß ®T "May" E. E. capable of been enjoined from ever again manu- forming the most intense magnetic fields. facturing or offering for sale, any medi- Persons placed under the cines of any kind Peace effect of this and the harvests of five Time Uses for the Search - ultra -powerful magnetic flux were care- hundred thousand to several million dollars light-A new scheme for outlining fully watched and every annually, is lost forever movement re- to them. Like all airplane field with' one search'ight, corded with remarkable accuracy and pre- schemes of this nature, these individuals by Edwin F. Linder, M. E., Special- cision. The pulse rate, heart produce testimonial beat, breath- upon testimonial to ist in Searchlight Design and In- ing, and reflex responses from the various prove ( ?) that their goods are as won- ventor of Bullet -proof Mirror. nerve centers were noted derful as they claim and in no case them to be and with The Automatic Telephone -Sim- was even the slightest change effected the boldest effrontery, produce advertise- when the person was first under ments such as "Five Hundred Dollars ple explanation in picture and in dia- magnetic will gram by an expert in Automatic influence and again when the current was be paid to any one who can prove that Telephony. turned off. these letters are not genuine, or have been solicited." This F!ashlighting This fact is well worth remembering. seems to pave the way to Birds and Animals, When once thoroly the enormous financial profits recorded by by Howard Taylor Middleton. learned, people will not them be bamboozled by any device which claims in income tax reports and demon- The "Loadstoue" as its healing strates to what an extent they have hood- or Natural Mag- power, magnetism of any winked the Public. net- Specially written by an expert sort. Under this category, come also such on loadstones, with special illustra- ridiculous schemes and such It is flagrant mis- only necessary for us to watch the tions. representations as Electro- magnetic Rings continuous panorama of advertisements which cure everything from which A Day With the Weatherman nose bleed bunko medicine houses use and view - down to appendicitis, and varicose veins. the daily death column in the paper to note The rôle of electro-mechanics in fore- the marked telling your daily weather report, by Another of the wonderful deafness cures similarity of names of persons which was perhaps who have died of the same disease, which, H. Il infield .S'ecor. more magical and mys- tical than the former was that of (Dr.) two days later, the cure -all concern an- "Odd Photo" Prize Contest. Branaman. nounces it had cured. "Dead men tell no This device would cure deaf- "House -hold Electrics" page, ness or catarrh, head noises or asthma, so tales" as the old adage goes, and hence, we by quickly will not stop to even question whether or Edna Purdy. that you would not even know it, regardless of what the deafness was due not the individuals concerned in the treat- The 11%hy and Wherefore of Mag- to. The poor afflicted victim was given a ment, ever had used it, but if so, the re- netism, by Edward A. Keever, symptom markable results are clearly indicated by blank which he filled out and the "slow procession." How Glass Is Made -All about whether he could add yes to every question glass, the everyday or no to every question asked thereon, One of the greatest frauds of all time substance about he which we know so little, by Prof. was either pronounced deaf or suffering and finally declared by the Government to Floyd L. Darrow. from catarrh. be simply a scheme for obtaining money The contrivance altho selling for $8.00, thru the mails by means of pretexts and Popular Astronomy, by Isabel M. cost about fraudulent promises, and to which further Lewis, M.A. $1.50 to make. Essentially, it is a leather belt strapt securely around the use of the mails was denied, was the "great" The Amateur head, and "wonderful" ACTINA humbug. Per- Magician -The Mys- made in the form of a pocket. This terious "Rapping Hand" which fore- houses the "battery." The battery is the haps many of our readers remember this tells your fortune, same as Actina inhaler, having probably seen ad- by Joseph H. employed in the audacious com- Kraus. mercial frauds even now being advertised vertisements of it thruout the country. and manufactured This device sold at about ten dollars and Long Waves and "Strays" on Rog- in the form of belts. later on, if the correspondents did not an- ers' Antennae, by Lieut. -Cont. A. These consist of a number of copper and swer, a 50 per cent discount on any goods Hoyt Taylor, U.S.N.R.F. zinc elements, the zinc being placed inside the copper. Around was offered. Some Laboratory!! the zinc element is a -An interesting tiny bit of felt so that when the battery is Essentially, it consists of an outer casing story with excellent photographs immersed about of in a vinegar solution an electric three inches long with a wide open- an American model worker's shop de current is set ing at one end, and a narrow opening luxe up! These electric currents at -Written as only he can write buzz thru the ears and the other. An inner tube of perforated it, by Thomas Reed. stimulate in that way, the nerves of hearing, according to zinc about / inch wide and fitting inside Dr. Branaman, the first tube or casing (this More Light for Microscopes, by America's leading ear spe- made of cop- cialist (at least he The American product, Merrill M. Hunting. calls himself that) ; he per). however, even went so far was entirely of steel. The space between as to publish advertisements in the newspapers showing the the two walls shown in illustration (1) was photograph of filled with oil of mustard and oil of sassa- a man as being cured of fras. The former deafness and blindness. This man had smells like a decayed yet we find here, a company deciding been deaf for years onion great caution that and was still deaf ; and must be exercised ozone can be generated by electric and this Dr. Branaman when smelling this oil, hence the Actina action knew. Still he ( ?) between the zinc and the copper, while persisted and continued to use the victim's advertisements stating that it was perfectly held in the hand. harmless Additional fakes made name in his advertising slogans. Strange were not only fraudulent, but also by the same concern were the to say, a testimonial of great injurious content. This swindle Magneto purported to have been Conservative Garment shówn in Fig. 3. written by the man, was printed "cured" deafness, blindness, catarrh, and This altho the garment, which was claimed to cure victim was so unfortunate as to be unable nervousness and a couple of other odds anything from indigestion to locomotor to write. and ends thrown in. ataxia, looked like a suit of underwear Even today, in some of our newspapers The American Medical Association, in with a large number of bar magnets, and magazines their exposé oodles perhaps we find advertise- propaganda, speaking of its and oodles of them, scattered thru- ments that start off with effect in curing any eye or ear out its interior. a big flare "Don't disease, shout, use the Morley ear phone." This state that the sufferer might just as well Such magnetic devices never cured nor (Continued on page 1312' ELECTRICAL EXPERIMENTER

ri F:1 411-11[1111 Ì t 11 1 1 ii 1 f I si 1 i 1 1 1 i f r 1(l li i ill flTi`Ti l ITITI MRiZZIT`177TH LECTRO- MEDICAL FRAUDS

MAGNE( IC FIELD;:.

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MAGNETO CONSERVATIVE 1/ CURING ACT( NA FRAUD GARMENT FOR EVERYTHIN" FOR 'URPiG'DEAFNESS

MORLEY EAR PHONE `CUR ES" DEAF.NES

ELECTRO -MAGNETIC` , HEAD CAP FO1 DEAFNESS `EAR -ACHES' AND ASTHMA'

ZINC

FELT COPPER 4 CONNECTOR

MAGNETIC BLANKET t9 - 5 N -S VACUUM HEAD °tom 't3= CAP TO MAKE 'S -,Y N HAIRGF04q 8

FULL DESCRIPTION ON OPPOSITE PAGE. 1256 ELECTRICAL EXPERIMENTER April, 1920 46 Ih CHARLES S. WOLFE THE Chief of Police gave me a hos- whole clan had no terrorizing influence on about them, anyway, Chief ?" queried Joe. tile questioning stare. I'm not ex- Joe. "Well, for thing, ceptionally quick one we can't find the witted, but I don't The Chief dropt wearily into the near- knife, or whatever it was that he was have to be hit with a club in order est chair. "You'll have to pardon me, stabbed with." to grasp an idea. I rose instantly. friend," he growled at me, "I'm a little "Murderer took it away with him," sug- "Something tells me I am de trop," I mur- short on manners at the best of times, and mured. gested Fenner. this thing is getting on my nerves. Joe," The Chief's face took on a pained look. My friend put out a protesting hand. turning to Fenner, I want you to help us "Maybe he did," he "Sit down, said, wearily, "only- you touchy ass," he said. again." there's no possible way he could "Chief, this man is a particular get in to friend of I turned a mental summersault. The stab the man in the first place, and no way mine. You can safely say anything in his Chief of Police addressing my chum as that he could get out presence. It go after he had stabbed will no farther." Joe. Asking him to help them-again. him in the second place. And in Undecided whether to go the third or stay, I hesi- Ye Gods ! Was my seemingly commonplace the crime simply tated. The Chief couldn't have been smiled sourly. "Oh, it's place chum a detective? committed at all, but it was. And there all right, Mister, if Joe here says so. But The Chief was speaking. "There was you are." forget anything you hear, get me? We a man killed in the Atwood building an "Chief, you're talking can't afford leaks." thru your hat," hour ago. I've just come from there." reproved the amazing Fenner with astound-

This Is a Story of An "Educated Harpoon," and We Are Not Going to Tell You In a Few Words Just What It Is or How It came About That a Great Business Man Was Murdered In His Private Office, Without Anyone Having Entered the Office, As the Facts of the Case Have Clearly Proven. However, If You Have a Fair Education In Electricaland Radio Matters, You May Be Able to Guess How the Man Was Killed. If Not, You Will Find This One of the Most Interesting Scientific Narrations Ever Written.

Joe saw that I intended to go, and he My face must have reflected the varying ing disregard crost of the deference due one in and forced me back into my chair. emotions that this statement produced the Chief's position. "There must be a "Don't mind the Chief, Bill," he said, within me, but Joe's countenance re- perfectly simple way in which some one laughingly. "He has an inherently sus- mained passive. "Murdered," he asked, got into the place and away again." picious disposition. Now then, Chief, what quietly. "How ?" The Chief arose. "My car's outside," is troubling you ?" "Stabbed in the back." The Chief might he said. "Come along down and have a I gasped. I knew Joe Fenner as a fel- have been saying "Please pass the pota- look." low student, wireless telegraph enthusiast toes," for all the .feeling exprest in his As Fenneriesitated I took_ my cue. "I'll and scientific dabbler. A mighty likable, tones. ride along as far as my house if you don't but not extraordinary, sort of a fellow. To Joe shrugged his shoulders. "I don't mind," I said. find him on terms of intimacy -to say think, you want me, then," he said. "It's "You'll ride along and have a look with nothing of equality -with the Chief of our out of my line." me," said Fenner, warmly. "I know you're city's police force was astounding. Per- "Yes, you'd think so," agreed the Chief, just as curious as I am to-get a took at sonally, I've always had a little fear of "if it wasn't for the peculiar circumstances the scene of this remarkable crime." policemen, a relic of boyhood days and surrounding the crime." The Chief was almost friendly. "Yes," pranks. Apparently the king -bee of the "Peculiar circumstances? What's peculiar (Continued on page 1335) April, 1920 ELECTRICAL EXPERIMENTER 1257

The Electric Bachebr Meld Surp-ised Her Friends One Eye. nn) by Giving an ' c On Fopping" Party. A :tick to 'Ntich the Corn Pospe- Wes Attached Waved Regalarl- tack aid Forth When trio scolie N achino Motor Was Ruff inn.

Ever/ Yong Woman Lite: T1i.ss Beauti- fu Eisu-e; with Tie Electric Batchelor Cr mot d Buff co, but Maid. Does Not Sha (fees Foregoes Confine the Motor Bwiec Then Because to the Sewing Ma- Sb, las Ilo Crimper. chine. She Cuts a An feectric Curling Cicular Felt Buffer Irat Is Wet to Be arai Fits It Onto the De :pórai As a Crimp- St aft of the Motor er of P.uff1 es When for an Electric Man One Has No Crimper. bore.

Mating an Electric J-a:ker Jar. A Hi -e Red Bulb Is In- sert- Thru the Top of the Cracker Ti.. and the Heat Is Just !nett When the Light ks O.t I Day a Week.

One of the Annoylig Efficient B r s s h i n s by Tt lite About "Vacuun- Meter. The Brush Con- lus" Is a Tangled Cori. nect:. :o the Shaft o- the A Celled Spring May New Nets Revo ses, and Its Be tircha5ed, or Maie Speed !s tegilated bT the by tie Handy Mechani:. Fest Psiki cf the Motor.

Here Is a Yew Comtination ìt A Nitrogen L a n p Held or Elatiea Deuces. It Is a Cis-l- Clamped to a Tin Dipper for a ing int. the Center Rod rf Wtics May Reflector, Gives a Surprising B; Puller Ou- treat Amount Heat, the Hendee, and Scrswed of Which May lib Be Directed Over the a o'. Niter Bag to Keep Entire k Head or Lined to D-y a Water Hsi as Long as N.edoeL Section. s t000a.emrw,ek a..,3ro uesurre ü.:- i s 1 2 5 8 ELECTRICAL EXPERIMENTER April, 1920 aüegTcomiph CxDll d RdO l 1637 PRERRE IS)Se BOUCHE RON,ONfl IF.,nngrft U. 5. H. R. F. fifty words or e- less. This form of message is Ì PbV(AL 7ELEGRAPH -COMMERCIAL CABLEGRAM charged for at . CI. . SO, one and one -half x the climes ,Li a .222.11 721.1102M ßJY, cACIrtC iINCdAPOPAIE EcIRAPN CAKE COMPANY IV iNE 11119 MEBSAGE SbBIECI í p,qN5M1Tí Ab0 OE0V05 TNEeACK OEIN15 BEAb, .;:i22: cii: r veS ANO COrO'N04: -e'NiEDON The Accompany- Ñ ing Illustration Na TM[ the Three _ NEtN Shows 4rr LvAI. n_ Principal Forms m "VIA COMMERCIAL" of Business Mes- e ..... AND CO sages as Com- JAMES BADIN monly Transmit- CheStaat dtreet, 7980 North NSfLTOBCO ted by TELE- tPARIS (PRANCE) C A B L E - Chicago. Illinois. GRAM, CAYPOSTOBE BOEADI61oR G R A M a n d AND D PRICES WIRELESS or WINN NOB. SOSfBROA.iTR ZBBRgsTOnO IMMEDIATE DELI79NY MARCONIGRAM. SONS T h e Underlying LAWSON 6 OSTRCO Key -Note, in ( Cheok words) 9 Bordel Out :Cbsok 10 Writing 01W epspted Bote: 511 words in text words eooatred wxaopt These Messages Bote. 0119 country of destination. for Transmission, Is of Course Brev- ity, with a Capi- tal "B." Many Useful and Prac- tical Hints for the Correct Prep- aration of Such Messages Are IRKED DEFERRED Given by the Au- thor In the Ac- companying Text. Altho the Pre- N GONINCCTiOai ferred Forms of TELEGRAPH COMPANY These Messages MARCONI WIRELESS Are Known Fairly OF AMERICA Well to Everyone, Sand the I0110Winb meeeape "VIA MARCONI '', +ublect to Yet It Is a Fact In, terme on back hereof, which are hereby a¡(reed. to. That a Brief and Fully Complete Message Which Shall Not Be Mis- .ham JAtA'iSON STEfJ1ER CAR/CAS (via? CAPEMAY understood by Recipient, - WREN DORI ?J1IP A.RRIVE BE4YORE. Rafit, TNOIIPSON re11 IIII, 1111)111

(Check 10 word.) .en -word cí 1y telegram, additional words being charged for at the rate of one - fifth of ARGE corporations of today do not in order to lower the cost of the message. initial rates for each additional ten words waste and take up the valuable time In either case much money and time was or less. of high- salaried executives by leav- lost in harangues and disputes between (4) The night letter is handled in practi- ing it to them to.prepare and prop- themselves and the cable clerks, which could O, G.AMIeS. flaim nn s erly route the dispatches of the have been avoided by securing the neces- 07, .7215 rP firm in the most economical way. Instead sary information in very short, order from .. Adb,.... m a specially trained clerk, preferably one who competent telegraph clerks or from other A.. has had experience in a telegraph or cable experienced persons. .d.M 7=7'M' b,.. e,M ..a nn. into 0. ,b.di.ftt office, is assigned to this work; and all tele- Besides the telephone there are three gen- tn. 017,4 Arlo. N RofI m'-r ,e.. grams, cablegrams and radiograms must eral means of rap'd verbal communication 07:15 A.ueoeuni be routed thru him before forwarding. with distant points as follows and in the 67225 ...mere However, since it is not every organization order of their importance: - n.. whose business warrants the employment of 1. The telegraph. tem such a clerk, nevertheless the smaller con- 2. The cables. mu cerns may profit by some timely information 3. The wireless. Aem Aem on this subject. Particularly is this needed THE TELEGRAM. ..-cri+=ü:°"....I..e-.-.,w a.. today, for in the mad scramble to "get the The telegraph as a means of communica- business" little details like economy in the tion is usually resorted to in this country =.. bbm- O 72.15 .120121a15222 . Pkaa use of words in telegrams and cablegrams where the telephone is too expensive, or AemoUbor are seldom taken seriously. where the special delivery mail is too slow, .15,n.í,.. The writer, who during the war had an and of the three mentioned above is the ro. yield opportunity to study various systems of most commonly known and used. 0725, , .1 ias communications, both government and com- CLASSES OF SERVICE. am, kkev mercial, was surprised at the lack of com- There are four classes of messages which 072, Aenatonts 1,5 mon sense and knowledge displayed by some : may he sent by telegraph 570a lich " GEÌEMS. firms and individuals when sending dis- (1) The telegram, for which full rate is ená nm.>..wee..v,..me but p;aiglm.rrynxmuryaper patches. In some instances no efforts were 07.4 Aemun ulWebori e.... charged and which is given expedited trans- íY.mh, ,..m... wr`-od.>-1 ` made to economize in the use of words, mission. It may contain ten or less words 0720 gm his ,,ea -, and in a fifteen -word cablegram of p.rn as many for the same charge, additional words be- pm ,bbw five ''. ..a,...M,xaenay. as unnecessary words would be used, ing charged for according to rate per word. emenain p0,i,ie. which in the case of messages destined to (2) The night message, which is handled t_ :ñ : remote points. costing 42 cents per word, during the night only when traffic is small meant a loss of $2.10. On the other hand, 07,10 Avne01.. l..:,.°w5e e,. .e. and for which reduced rates are charged. ryAa.. . Notify m.5.47. there were those who were seeking econ- This message is usually delivered in the A Page from One of the Famous Telegraph omy by the wrong methods, and thru lack morning of the following business day. and Cable "Code Books" (Lieber's Code). By of proper knowledge of rules would attempt the Use of a Single "Code Word" You Can (3) The day letter is transmitted during Transmit a Whole Sentence, Thus Reducing to combine words in an illegitimate manner slack periods of the day and may contain the Cost Remarkably. April, 1920 ELECTRICAL EXPERIMENTER 1259

tally the same manner as the night message, but may contain fifty or less words, and is charged for at the same rate as a regular day telegram for fifty words. Additional words are charged for at the rate of one - fifth of the regular day message rate for every ten words or less. Note: Day an light lettergrams must be written in plain' English, foreign language, code or cipher not being accepted by telegraph companies. The domestic telegraph message differs essentialy from the cable and wireless in that the text is the only part charged for; the address and signature being sent free of cost to the sender. Some essential and general rules regarding the transmission of telegraph messages may be briefly described as follows : (1) The complete address as well as one signature are not counted nor charged for. (2) Any dictionary word Of a recognized language, that is, the English, German, French, Italian, Dutch, Portuguese or Latin, may be used and will be counted as one word, no matter how many,letters the word contains. (3) All numerals, decimal points, punc- tuation points, whether isolated or together, are counted and charged for as one word each. (4) Names of places, states or countries, such as New York City, Havre de Grace, Camp Dix, District of Columbia, East St. Photo Courtesy Donald McNicol. Louis, South Orange, may be combined and And Speaking of the Dispatch of Telegraph Messages -Here Is the "Distribution Board" counted as one word each, and in order to Which Links Our Local Telegraph Office, Manned by Two or Three Operators, with the Large Staff of Telegraphers iln the Main Telegraph Exchange In New York City. Each simplify counting, should be written thus : Operator's Position on the Long Dispatch Tables Is Connected with a "Tell- Tale" Signal Newyorkcity, Havredegrace, etc. Lamp on the Front of the Switchboard. The Operator, who Sits in Front of this Board, (5) Mutilated dictionary words, written Can Thus See at Any Instant Just Which Operators Are Idle. A,Branch Exchange, De- siring to Transmit a Message, Signals Thru a Lamp on the Table of the Board, and All together contrary to accepted usage of the the Operator Has Then to Do is to Take One of the Plugs Beside This Lamp and Con- language, or combinations of several dic- nect It with a Jack Connecting with an Idle Operator. The Battery of Relays on the tionary words will be counted and charged Right -Hand Side of the Frame Are Connected to the Various Branch Exchange Circuits and Cause the Signal Light In Each Case to Remain Lit Until Connection Is Properly for according to the number of words they Made by the Distribution Operator. are composed of. For example, such words as "firstclass, "allright," "postoffice," etc., extra words, whichever the case may be. destined, such as France, Italy, etc. In pre- are counted as two words. (9) Numerals in the body of a domestic paring the message these names are usually (6) Such words as "parcelpost," "per- message are counted and charged for as one bracketed to avoid counting and charging cent," "carload," "O.K.," "A.M.," "P.M.," word for each individual numeral. for them. The manner of counting words "C. O. D.," "F. O. B.," are counted and THE CABLEGRAM. is known and usually referred to as the charged for as one word each, because The cablegram is a more complex and "cable count,' which same is also employed these are recognized by custom to be sin- detailed subject than the domestic telegram, in checking wireless messages or radio- gle words. and in.order to avoid errors requires judg- grams. Owing to the fact that cablegrams i (7) Code words and cipher words may be ment and accuracy on the part of -the sender. are expensive, commercial houses make ex- used. Code words not exceeding ten letters, One reason for this is that it is usually sent tensive use of code and cipher in order to and cipher words not exceeding five letters to foreign lands, which entails handling by lessen the number of words and therefore are counted and charged for as one word many hands, and the cost is considerably reduce the cost. each. greater per word than the telegram. In the Several well -known codessin commercial (8) Only one address and one signature case of the cablegram, every part of the use today are: are allowed in one message, two or more message is charged for with one exception ABC Codes, 4thand 5th Editions. signatures being charged for as so many -the name of the country to which it is Lieber's Improved Code. Western Union Code. A. I. Code. Bentley's Code. Century Code. Scott's Code, 10th Edition. Riverside Code. Imperial Code. Bromley's Code. Broomhall's Code. Typical code words : Codiac, Gopher, Staticallo, Nomadimice. DIFFERENCE BETWEEN PLAIN LANGUAGE, CODE AND CIPHER. Plain language, as referred to in cablegrams or radiograms, may be any language using the Latin alphabet and Arabic system of numerals. In using plain language in a cable or radiogram any legitimate word may be counted as one word up to and including fifteen letters ; beyond that point and for each additional fifteen letters it is considered and charged for as two words, tho the word need not necessarily be disconnected. For instance, the word "unconsti- tutional," which contains sixteen letters, is counted as two words. Code language consists of genuine or artificial words of a pronounceable nature, but which may have a different face meaning and are counted and charged for at the Many of Us No Doubt Entertain the Idea That There Are Two or Three Undersea Cables rate of ten letters to the word. When code Spanning the Atlantic Ocean Between Europe and America, but a Glance at This Latest words of an artificial nature exceed ten Cable Map of the Atlantic Ocean Tells a Different Story. There Are, In All, Seventeen Cables Linking the Old and the New Worlds. (Continued on page 1298) 1260 ELECTRICAL EXPERIMENTER April, 1920 Weilt e art By LOUIS DERR Professor of Physics, Massachusetts Institute of Technology. Specially Written for the Electrical Experimenter IF the earth could be weighed like line was placed just south of the moun- a load of coal, how much would tain, another just north of it. Now, it weigh ? Is it composed of from the known circumference of the light materials principally, or earth and the measured distance be- heavy ones? How can anything tween the plumb -lines, the difference be learned about the matter? It is the of longitude between the two stations purpose of this article to give a brief could easily be calculated, and the outline of some of the methods by angle between the vertically hanging which questions like these are an- plumb -lines would have been 41 sec- swered. onds of arc if the mountain were not Sir Isaac Newton's celebrated law there. Actually the angle was 53 sec- of universal gravitation, publisht in onds, the mountain having pulled the 1687, states that every particle of mat- plumb -line six seconds out of the verter attracts every other particle with a tical on each side. This is indicated in force proportional to the product of the figure. their masses, and inversely propor- From this, as before, the relative pull tional to the square of the distance be- of the mountain and the earth on the tween them. As may readily be im- suspended bob could be determined, agined, the law was deduced from and when geologists had studied the astronomical facts, and finds its most mountain and estimated its mass the important applications in astronomy, mass of the earth could be easily com- for by it the motions of the moon, puted. Its average density came out the planets and other celestial bodies 4.71 times that of water. Other trials, are determined. near Edinburgh, gave 5.32. There are, however, too many un- The weak point of the method is known factors in the formula to make the difficulty of accurately estimating it directly available for calculating the the mass of the attracting hill or mass of the earth from astronomical mountain, and therefore the results data. Five quantities are involved, of obtained by methods involving the which four must be known in order measurement of earth masses cannot to calculate the fifth : the force be- be accepted as accurate. It is ob- tween the two bodies, their respective viously necessary to have everything masses, the distance separating them, under complete control, and this has and a numerical constant whose value been accomplisht in several ways. depends on the units in which force, Poynting's method (1890) is as fol- mass and distance are exprest. If we lows: Two metal balls were carefully wish to know the mass of the earth in Fig. 8. This Shows the Remarkably Sensitive Caven- counterpoised on a very delicate bal- pounds or tons, we must take some dish Type Apparatus With the Small and Large Lead ance, and the position of the balance selected body on the earth's surface Balls, Reflecting Mirror, Etc., Actually Used in Deter- mining the Weight pointer noted by an observer looking and compare the earth's attraction for and Density of the Earth, at the through a telescope from another it Present Date, by Professor Louis Derr and His Asso- with the attraction of some other ciates at the Massachusetts Institute of Technology, room. Then a huge ball of lead weigh- known body for it, at a known dis- Cambridge, Mass. ing 350 pounds was cautiously moved tance. The working difficulty is that to a position just below one of the sus- bodies of manageable size, separated by The problem is an old one, and has been attacked many times and from many angles. The results obtained are usually given in figures representing the average density of the earth, a quantity of perhaps more scientific interest than the mere statement of its mass. Of course, if the mass and volume are known the average density is found simply by dividing one by the other. Perhaps the earliest definite results are those obtained by the French physicist, Fig. 1. Diagram Showing How the French Bouguer, about 1740. He hung up a plumb- Physicist, Bouguer, Attempted to Weigh the line, ten miles east of the great mountain Earth by Noting the Pull of a Mountain mass of the Cordilleras Mass on a Suspended Bob, or Weight, In in Peru, and then 1740. A Deflection of 16 Seconds of Arc Was moved it close to the mountain range. He Fig. 3. This Shows Poynting's Method of Actually Observed, and From This Ratio, as reasoned that if the mountains exerted any Weighing the Earth. Two Metal Balls Were Compared to the Pull of the Earth Upon the attraction for the suspended Carefully Counterpoised on a Delicate Bal- Bob, lt Was Possible to Compute the Aver- bob, the line ance or Scale. A Large Ball of Lead Was age Density of the Earth. would no longer hang vertically, but would Then Moved to a Position Just Below One be tipt slightly. This is shown in Fig. 1. of the Suspended Balls and Its Direction Caused the Balance to Tip. The Pull of the The deflection was actually observed. and Large Ball Could Thus Be Weighed Directly, was found to be about sixteen seconds of Having Been About One Millionth of a Pound. arc. This gave a ratio between the pull of the mountain on the hanging bob and the pull of the earth upon it (its weight, of course) and from this ratio it was possible to compute the average density of the earth, which was figured out as about twelve times the density of water. The experiments were carried out with great difficulty, and the result is now Fig. 2. This Shows the Arrangement Fol. known to be lowed by Rev. Nevi! Maskelyne in 1774, In much too large, but Bouguer's work was Which Case He Chose a Mountain In Scot- of pioneer importance in that it showed Fig. 4. This Illustrates a More Advanced land for His Experiments. One Plumb Line that the earth is denser than Method Was Placed South of the Mountain, and water, that it of Weighing the Earth, Devised by Another North of lt. The Ratio Between the could not be regarded as hollow, in view of Henry Cavendish, In London, In 1798. In the large This Case Two Small Metal Balls Are Sus- Pull of the Earth and the Pull of the Moun- average density, and that moun- pended tain Was Readily Observed, and the Density tain masses do attract. From a Fine Wire, and Two Larger of the Earth Then Computed. Lead Balls Are Then Placed, One Behind In 1774 the Rev. Nevil Tfackelyne, As- and the Other In Front of the Suspended controllable distances, exert so feeble a Balls. The Attraction of the Large Balls tronomer Royal of Great Britain, employed Thus Deflected the Rod Carrying the Small gravitational pull upon each other that the a somewhat different method, choosing a Masses, and This Deflection Could Be Re- measurement is a problem of considerable mountain in Scotland for his experiments. corded or Thrown on a Screen, by Means of magnitude. Fig. 2 shows his a Mirror Mounted on the Suspension Wire arrangements. One plumb- and on Which a Beam of Light Was Focused. April, 1920 ELECTRICAL EXPERIMENTER 1261 pended balls, and its attraction caused the balance to tip slightly, as indicated in Fig. 3. The pull of the 350 -pound ball was thus weighed directly ; in the actual experiment it was about one millionth of a pound. But the most accurate results of all have been obtained thru a method devised by Rev. John Mitchell. He did not live to carry out his project, and the experiments were first made by Henry Cavendish in London, in 1798. Cavendish took a slender rod seven feet long with a small metal ball at each end and suspended it horizontally by a very fine wire. A large ball of lead, twelve inches in diameter, was then brought up in front of one of the suspended balls, and a second lead ball of the same size placed behind the other suspended ball, as shown in plan in Fig. 4. The attraction of the large balls thus deflected the rod and the hanging balls, until the deflecting pull was just balanced by the twist in the wire. The force was then calculated from the de- Fig. 5. The Early Cavendish Apparatus Is Shown at Left. A More Modern Type of flection. Cavendish Balance Is Shown at the Right, Within recent years the apparatus of and Which Was Much Improved and Gained Cavendish has been much improved and Vastly Greater Sensitivity Under Develop- ment by Prof. C. V. Boys, a Noted British given vastly greater sensitiveness, especially Physicist. by Prof. C. V. Boys, a noted British physi- ,,,11,,,1,,,,,,,1,,,,111111,111111111,,,,,,,,111,,,111,,,,,111111,111,,,,,,,,1,,,,,,,,1,,,,,111111,,,,111,11,1111 cist. Fig. 5 shows one form of the apparatus. sionally shown at some of the larger col- start with a knowledge of the force, the The suspended balls weigh one- fortieth leges and technical schools. With the ap- distance and one of the masses, and com- of an ounce each, and are about an inch paratus at rest, the spot of light on the pute the other mass -the mass of the earth. and a half apart. The large attracting wall is almost motionless, perhaps quiver- A simple proportion, derived from the ex- masses are of lead, about the size of a base- ing a little when someone treads heavily periment just described, then gives the mass ball, and weigh about six pounds each. The on the floor above. But when the large of the earth directly. suspension is a fine thread of quartz, eigh- lead balls are moved into position, altho The resulting figure is so stupendous teen inches long and about one- twelfth the nothing apparently happens for a minute or that it is utterly meaningless : the mass of diameter of a human hair. Fig. 6 shows thereabouts, the spot of light then begins to the earth is 6,000,000,000,000,000,000,000 (six the quartz thread and a human hair equally creep slowly over the scale with a motion sextillon) tons. It may be added that its magnified, and it must be admitted that the that very slowly but surely increases until average density is 5.52 times that of water. quartz thread is much the handsomer of the displacement is a yard or more on a the two. The fibers are made by melting wall forty or fifty feet away. No haste the edges of two quartz crystals together can be expected, for with the apparatus THE "UNIVERSE" ON A SMALL and then quickly sepan ing them, just as illustrated the force on the little balls is SCALE. glass threads may be ch awn by heating a "Mars always challenges interest," says glass rod in the middle and pulling the William Joseph Showalter in a recent com- ends apart. munication to the National Geographic So- The deflection, which is very small, may ciety. be made visible to an audience in the fol- "It is quite generally believed that Mars lowing way. A tiny mirror is fastened to has ice -capt poles. The telescope reveals the little rod carrying the swinging balls, white spots at the @poles that have every as shown in Fig. 7, and a narrow beam of appearance of being like our ocean Polar light from an electric lamp is reflected from region. They advance toward the equator the mirror upon a scale on a distant wall. E E. in winter and retreat in summer. In the Any motion of the mirror is thus shown summer of 1916, Pickering, who, with by a displacement of the spot of light on Fig. 6. This Photo Shows the Remarkable Lowell, has led the school of astronomers Smoothness and Even Diameter of a Quartz the wall, and the device practically amounts Thread Compared to a Human Halr, Both who believe the can see canals on Mars, to putting a long pointer on the swinging Equally Magnified. The Quartz Thread Is said that he found the white caps stretching arm, a pointer of any desired length, per- Used to Suspend the Two Small Balls In the farther down toward the equator than he fect stiffness and no weight! Cavendish Balance. had ever seen them before. The apparatus requires various acces- "He said that if there was any connection sories, an extremely steady support for the no greater than the weight of about one between the weather of Mars and that of suspended balls being the most important. one -hundred -thousandth of an inch of hu- the earth the winter of 1916-17 would be This steadiness is obtained by mounting the man hair! the coldest in many years. It was true. swinging system on a heavy iron frame or The "conscientious objector" now rises May it yet be possible to do long -range cage hung from a bracket on the wall of to ask how it is possible to measure a force weather forecasting on the earth by study- the room and provided with large adjust- so absurdly small, and the answer is that ing the waxing and waning of the ice -cap able weights at its extremities. These the force is not measured directly, but ob- on the South Pole of Mars? weights are set by trial at such points as to tained by calculation. By knowing the our most graphic picture of the destroy accidental vibrations as completely weights and the dimensions of the swing- solar system is given by Herschel. Imagine as possible, and when properly adjusted ing parts of the apparatus, and the time a circular field two and a half miles in they are very effective. Fig. 8 shows the required for a complete swing back and diameter; place a library globe two feet in arrangement worked out at the Massachu- forth (just as the balance wheel of a watch diameter in the very center ; eighty -two feet setts Institute of Technology. swings), it is possible to calculate the force away put a mustard seed. The globe will The experiment, tho not spectacular, is required to produce any given deflection, represent the sun and the mustard seed nevertheless a striking one, and is occa- and in this way the pull of the lead balls Mercury. on the suspended system may be figured. "At a distance of 142 feet place a pea, With the apparatus shown, one complete and another at 215 feet. These will repre- swing requires about three- quarters of an sent Venus and the earth both as to size hour. and distance. A rather large pinhead at a " To sum up : The experiment determines distance of 327 feet will speak for Mars, Mirror... the actual force between two known masses, and a fair -sized tangerine a quarter of a S I I ------ll at a known distance apart. If we consider mile distant will stand for Jupiter. A small -- il a ten -pound ball lying on the ground we lemon at two -fifths of a mile will play the I have a closely similar case. We know the rôle of Saturn, a large cherry three -fourths Camp pull of the earth on the ten -pound ball - of a mile distant will answer for Uranus, obviously ten pounds' weight. We know and a fair -sized plum at the very edge of the distance between the ball and the at- the field will proclaim Neptune. FI G.7 tracting center of the earth -four thou- "Eighty moons would be required to Fig. 7. This Diagram Shows How a Narrow sand miles. We know the mass of the ball make one earth. A player there could Beam of Light Is Reflected From a Mirror -ten pounds. With the Cavendish appa- throw a ball six times as far as it can be on the Quartz Fiber, Suspending the Swing- ing Balls In the Cavendish Balance, Used In ratus we start by knowing the distance and thrown on American diamonds. A man Determining the Density and Weight of the both masses, and then determine the force; weighing 150 pounds there would weich 900 Earth. with the ten -pound ball on the ground we on the earth." 1 )6? ELECTRICAL EXPERIMENTER April, 1920 Eefyiirsxg Cxxi )B3o.n'e5 mnd ;B3 ocso°oo y n©BER`Pi G. 5NIERRE .).CT THE towboat of to -day does not guidance and, within the limits imposed by make the most of its store of MaTflLrlle TTc'nnspÚTetm® the linking electrical conductor, enjoy con- mechanical energy. It fails for a siderable freedom of action. With each variety of reasons, but primarily tñ®n by EIlec4rnfied charge properly motored and fitted with a because its screw or screws are in- suitable screw for a given maximum speed, capable of getting a full grip upon the ITc'aIlIleTc's and the power boat similarly equipt for

X _ ELECTRIC POWER ANOCONTROL PLF>,IYT OR TUG

ELECTRIC MOTORS DRIVING PROPELLERS ON CAR FLOATS

Entire Group is 1 -In This Case the Flanking Car Floats are Each Equipt with Twin Screws Electrically Operated, and the Control of the in the Hands of the Man in the Pilot House of the Central Vessel. By "Going Ahead" On One Barge and "Backing" with the Other, It Would Be Entirely Feasible to Turn the Whole Tow Within a Small Circle. 2-This Diagram Illustrates One -half of the Propelling Equip- ment, An Electric Motor, of a Car Float. 3-A Photograph of the "New Era" Preceding the "DAWN" from Which She Obtained Her Ener- gizing Current. Nearby is Seen the Pulley Over Which the Electrical Conductor Passes and Immediately Below is Visible a Part of the Reel At the Bow of the "DAWN." 4-A Fleet of Electrically Propelled Barges Making Their Way Thru a Canal. It Will Be Observed That the Prime Mover, the Source of Energy, is a Freight -laden Craft At the Rear of the Line. water when drawing one or more power- itself. In these days of high prices and efficient operation at towing speeds, the less craft. A propeller to be efficient must general insistence upon operative efficiency whole string would be able to maintain actually advance thru the water propor- there is a crying need for something better a pace much faster than that possible if tionately to its speed of revolution, and than the tug as a handy marine tractor. the same propulsive effort were exerted by the force of its drive is dependent upon Fortunately, a line of improvement has a tug, as is now the case. the number of times it turns in the course been pointed out and convincingly demon- Mr. Donnelly has planned that his sys- of a minute. If it revolves rapidly with- strated by Mr. William T. Donnelly of tem be adapted to coastwise and ocean out moving on it churns up the water, New York City. transportation. In the latter case, while pumps down air, and, to a more or less Mr. Donnelly proposes to turn the erst- the electric cable would not be expected pronounced extent, whirls around in a while tug into a navigable power station, to exert a pull, still he is satisfied, by rea- mixed or agitated medium which is hard generating electricity for its own drive and son of technical developments, that the con- to get hold of effectively. for the unit propulsion of its string of ductor can be built strong enough to per- Now this is pretty much the state of tows. The several vessels that would thus mit it to serve as a tow line in an emer- affairs when a tug heads the line of a draw upon the floating central station gency, involving motor breakdown on any string of barges or canal boats. Should would be equipt with electric motors for of the convoy. For this purpose his cable the convoy be laden, then the tug struggles driving their respective screws. Making would be patterned with a copper core with all of its power to make headway, due allowances for the power losses be- suitably insulated, then wrapt with hemp but the rate of advance is not in keeping tween the generator and the motors depen- and finally armored with steel wire, the with the speed at which the steamer would dent upon it, taking into account wastage latter giving the needful strength and serv- move if free and developing the same incidental to transmission, et cetera, Mr. ing at the same time as a "ground" for measure of energy. In short, its task is Donnelly has establisht the fact that a given the circuit. For deep -sea work, the object something akin to a freight locomotive, initial power development can be thus ap- in making the distributing cable strong attached to a train, trying to mount a gra- portioned and yield distinctly superior re- enough to bear a linking stress would be dient on wet tracks, but with this differ- sults in the common speed of a nautical to hold the various units of the tow to- .., ence -the tug must take the water as it train, so to speak. Further, the central gether during a storm, thus taking care of finds 'it, but the locomotive can "sand the station can, with equally good effect, either "lame ducks" and enabling the whole fleet rails." head or follow its charges or, if desirable, to help one another for the time being. But the towboat is further hampered by the tows can be secured on one or both when heading up into the wind and waves. the conditions under which it has to work. sides of the master craft. As a substitute for river freight -and- For instance, its churning propeller drives To begin with, an arrangement of this passenger steamers and kindred craft ply- rearward a veritable mill race -directly nature reasonably promises to add tre- ing our Great Lakes and semi -protected of the oncoming convoy. mendously to the ease with which a num- coastal waters upoi. daily schedules, Mr. against the bows to specially As a consequence, this disturbance virtu- ber of boats so energized can thread a Donnelly would have recourse ally adds to the load to be drawn by turn- tortuous channel or a busy waterway, for designed navigable centra stations, capa- ing the steam vessel's own efforts against each unit will be susceptible of independent (Continued on page 1319) April, 1920 ELECTRICAL EXPERIMENTER 2h3

o Ann 0 veo TaifA CEM By PROF. A. O A 1iR"E Professor of Physics, Imperial College of Science and Technology, London, England. Written Especially for the Electrical Experimenter. to a distance by means of wires, and, passing thru the electromagnet in the receiver, alter the amount of the attraction which the magnet exerts on an, iron diafram, which is thus set in vibration, and the original sounds are reproduced. Now, it will blear that any means by which we can cause'a. current of electricity to fluctuate in accordance with the vibrations of speech will provide a method of telephony. And if ,this current can be operated by means of a beam of light projected from some distance away, it will be possible to dispense with the wires between sending and receiving stations. Graham Bell solved this problem by using the remarkable element called selenium. This substance is, Fig. 4. This Shows the Latest Type Light - ordinarily, a bad conductor of electricity, ray Transmitter Arranged for Use with Light Fig. 3 Shows the Mount of the Vibrating but if it is illuminated by a beam of light, from the Sun. Mirror On the Phonograph Sound Box. When the Voice Waves are Spoken Into the Trum- its conductivity is increased. Thus if a pet They Cause the Diafram to Vibrate, and thin layer of selenium is connected with an Also the Small Mirror Attached On An Arm, electric battery and kept in the dark, a means of the lens on the selenium cell. Secured to the Center of the Diafram. small current flows thru it. If it is now What will happen? Every time the light placed near a bright light, the current is gets bright the current in the receiver will FORTY years ago ordinary telephony very much increased. Different colors have increase. Every time it gets dim, there will was a novelty. Today the telephone different effects. Red light is more effec- be a reduction of current. Actually, of is part of the equipment of most tive than blue, but, generally speaking, the course, these fluctuations of light occur far modern houses, and we use it with- whole of the constituents of white light too rapidly to be visible -perhaps 1,000 per out often thinking of the ingenuity contribute to the increased conductivity. It second. But the selenium is affected by which resulted in its invention. It comes is not within the scope of this article to them, and the variations of light are copied as a surprise to find that telephony by describe the manufacture of a selenium cell. by the variations of current, and one hears, means of light, the Photophone -which is Suffice it to say that it has to be prepared as it were, the light speaking. Figure 1 still a great novelty-was invented almost in a thin layer, annealed at a special tem- then represents the arrangement of the as soon as the ordinary telephone. Appro- perature, and mounted with two terminals receiver in "telephony by light." priately enough, the We have now to inventor of b o t h consider the prob- was one and the lem of the trans- same person -Alex- mitter, that is, the ander Graham Bell. means whereby the It was in 1880 that vibrations of speech he succeeded in com- can be imprest upon municating speech, a beam of light, so by means of a beam as to make it fluc- of sunlight, over a tuate accordingly. distance of about There are two pos- 200 yards. This was sible methods of a very remarkable procedure. O n e achievement, and it may either endeavor is difficult to under- to make speech stand why it has vibrations control failed to be de- the brightness of a velopt to any great source of light it- extent until recent- self, or use the ly. Various experi- vibrations for the menters have work- purpose of inter- ed intermittently on rupting the l i g h t the subject, with a proceeding from a view to improving steady source. The Graham Bell's latter procedure methods, but the was adopted by fact remains that Graham Bell, and development h a s he describes two been devices in this con- extraordinarily 1- Simple Form of Receiving Circuit for Use In Photophone, Comprising Light- sensitive De- slow in comparison vice, Such as a Selenium Cell, Connected in Serles with a Battery and Telephone. 2 -This nection. It is un- with that of tele- Diagram Shows How Rays from Source of Light are Past Thru a Lens and Grid On to a likely that the first phony over wires. Vibrating Mirror Mounted On an Arm Attached to a Phonograph Sound -box Diafram at the of these ever Right, and How This Beam is Reflected Thru a Second Lens and Grid On Its Way to the The subject is, how- Receiving Set. Proved successful, ever, a very fasci- but it is mentioned nating one, and it is the purpose of this for leading the electric current in and out. here because of its relation to the author's article to explain the principles and methods It then goes commonly by the name of a method, which will be described later. involved. "selenium cell." It acts as a sort of elec- Bell proposed to construct two grids con- In ordinary telephony we speak into the tric valve, permitting a big current to pass sisting of parallel strips alternately opaque transmitter and thereby cause a diafram to when brightly illuminated, and only a small and transparent. One of these grids was vibrate in accordance with the vibrations one when in the dark. to be fixt, the other attached to a diafram constituting the speech sounds. The dia- Look now at Figure 1. On the right at the end of a trumpet. The grids were fram in moving to and fro compresses to a hand side are shown a selenium cell, a bat- to be placed parallel to one another, and varying degree the carbon granules con- tery and a telephone receiver in series. A originally so that the opaque strips of the tained in the microphone. Comprest car- current is flowing thru the receiver, but one covered up the spaces of the other. A bon is a better conductor of electricity than it is only when the current fluctuates that beam of light fell upon the grids, and the carbon loosely packed, and therefore, if we sounds will be heard. Now, later on, we amount of light penetrating the pair would connect an electric battery to the micro- shall describe how it is possible to make a depend on their relative position. By phone, we obtain a current of electricity beam of light fluctuate in intensity in ac- speaking into the trumpet the diafram which fluctuates in magnitude in accord- cordance with the vibrations of speech would be made to vibrate, and, conse- ance with the vibrations of the diafram. sounds. For the moment let us suppose we quently, the "shutter" formed by the grids These fluctuations of current are conveyed have such a beam and that we focus it by (Continued on page 1315) 1264 ELECTRICAL EXPERIMENTER April, 1920 Sawing ilce By "Motor"

It takes a thief tric ice sawing ma- to catch a thief, chine, which obtains they say, and so it its current thru a has finally come to flexible insulated pass that the elec- cable, running to tric current steps in an electric power to really cut ice line near thé pond, with anything like the work of putting efficiency,-or what 60,000 tons of ice in was once a current the ice -house of of water. In other the Boston Ice Co., words, this is a case at Wellesley, Mass., of when current was completed this meets current - to winter in record - paraphrase the old breaking time. Wage "when Greek The ice reaches meets Greek." the machine in T h e twentieth twenty -foot squares century way of cut- and the four cylin- ting ice on ponds der saws cut them and rivers, is to into the regulation utilize electric cur- size cakes. rent to operate a Besides the elec- powerful mot o r, trically driven saws which in turn is there are in use connected thru gear- many gasoline en- ing or directly to gine driven saws for a large saw which ice cutting. A Ford tears thru the ice at engine makes a good prodigious speed. powerful prime The 20th Century Way of Cutting Ice on Ponds and Rivers, Is to Utilize Electric Current as With the aid of Shown Herewith. The Current Is Transmitted to the Motor Within the Saw Machinery, Thru mover for such a this powerful elec- Flexible Rubber - Covered Cable Running to the Shore. Gasoline Driven Saws Are Also Used. saw.

ThIlet 1FIlre limrma. 667 Rsfl,

NOW that everything in the line of could have been saved if the sprinkler is suspended to the cord which is also con- safety apparatus and fire announcers had been promptly shut off. Knowing the nected directly to the lever starting the has been invented, a New York difficulties and the faults of the methods phonographic mechanism. Another cord genius, a fireman, to be more specific, has used to -day, the inventor has developed runs up thru the box and has another fuse perfected and patented a device which not mechanisms which are actuated by weights link inserted in it, the latter outside of the only gives instant alarm in case of fire, in which electric current plays but a very box as illustrated. The cord now passes but also notifies its precise and exact loca- small part, and as long as gravity exists thru the box again and is connected to the tion, making the announcement when the the mechanism is absolute and positive in Bell telephone receiver hook. heat in a room reaches about 130 degrees its action. When a fire breaks out in any particu- Fahrenheit, which is considerably lower Fuse links are another feature of this lar portion of the building, one of the fuses than the temperature at which the sprinkler invention. These join together lengths of (Continued on page 1317) system would operate. In this way, an- cord or very thin wire. This nouncement of the fire is made long be- taut wire running thru a series fore the automatic sprinklers flood the of pulleys finally terminates in apartment or building with water, thus the fireproof box containing the ruining by water a lot df material which phonograph apparatus. A weight

l i mmim,,,,m,,, m,,trummu,,,mummi, "Hello, Operator! - There Is a Fire at 188 Blank Street, In the Warehouse on the Second Floor, Front. Notify Fire Headquarters at York 1,000. Central, there Is . Etc." Thls Is a Fire Alarm Call SPOKEN Over the Telephone by This Latest Fire Alarm Device. Diagram at Right Shows Fus- ible Links "L" In- serted in Taut Cord Which Releases Phonograph, As Soon As the Links Are Melted. lllllllllllllllllllllllllllllllllllllllllllllllllllllll@ Diagram at Left Shows Electric Thermostats Which May Be Placed on the Ceiling About 10 Feet Apart, and Electric Relay or Tripping Device for Starting Phono- graph in Case of Fire. When the Fusible Link Just Above the Cabinet Melts, the Phono- graph Is Shut Off, and the Telephone Hook Is Restored to Normal Condi- tion.

I 1111 I MI April, 1920 ELECTRICAL EXPERIMENTER 1265 A u .eOlumO :bile He S ELECTRIC STEERING NEW AUTOMOTIVE WHEEL HEATER. AMMETERS. This newest electric win- Two new ammeters for ter driving comfort consists automobiles, motor boats, , of two neat leather covered airplanes and other auto - grips, one for each hand, motives have recently been which lace on to the steer- added to a well -known line ing wheel at any place con- of instruments. venient for driving. Spe- The type of ammeter cial resistance wires are shown is an inexpensive in- cleverly arranged between strument, but is rugged, re- two copper plates in such liable and amply accurate a way that a very small for the service for which current is sufficient to keep it is intended. It operates the grips warm. They oper- on the polarized -vane prin- ate on the same principle as ciple, without springs or an electric heating pad. moving coils, is dead beat After a certain heat is ob- and can withstand momen- tained the heaters will get tary overloads of 500 am- no hotter, but retain an peres without injury. even temperature. They are The dial is two inches in simple, neat and efficient. diameter, and the scale A type designed specially This Is the "Ford" of Europe in the Central Sections. The Power Plant Is which indicates amperages for the Ford car is heated Entirely Mounted on the Front Above the Wheel. Photo -Edna Purdy. of from 15 to 30, charge by electricity from the mag- and discharge, is an inch neto. and a half long. Either black dials with Safety demands a firm grip of the steer- NEW MAGNETO FOR FORDSON white figures and needles, or white dials ing wheel which you cannot get with cold TRACTOR. with black figures and needles can be sup- fingers. The new device keeps your fingers plied. The meter is arranged for flush limber, with only a pair of light gauntlets One of the neatest and most effective mounting in the dash or cowl. on, which enables you to grip the wheel easy- starting ignition appliances yet pro- The second type of ammeter was origi- tight on the coldest winter days, giving you duced for the Fordson is the new model nally designed for government radio serv- a safe feeling even while driving over pave- magneto fitted with an impulse starter ments slippery with ice. coupling. One slow turn of the crank of the engine gives ignition results ordinarily had at 500 revolutions per minute, due to the impulse starter giving a quick spin to the magneto rotor shaft. The new outfit is chain driven from the front end of the crankshaft, the unit being located on the left side of the engine, where it is away from exhaust heat, a most important advantage when the destructive effect of the heat is considered. The heat quickly de- stroys distributor blocks and reduces the magnetic life of the magnets. In this magneto all this has been eliminated. All that is needed for installation is a wrench. No holes need be drilled, or any parts removed or discarded. As shown in the ac- Electrically Heated Steering Wheel for companying illustration, the magneto rests Autos. The heater coils use only half the current Latest Type of Auto Ammeter. White or necessary for electric headlights. They are Black Dials Are Available on These Meters. or operated from the same storage battery ice, and is the smallest d'Arsonval instru- magneto that supplies the headlights and in ment made. Tho but two inches in body are easy to attach. They can be put on diameter, this instrument possesses all of ten minutes. There are no bolts or screws, the delicacy of action, high sensibility, or holes to bore; lace on -wire up- that's great accuracy and ruggedness of the stand- all. ard switch -board type. It is supplied for flush as well as projection mounting. Volt- AUTO PARKING LIGHT. meters with scales ranging from 3 volts up- In order to save current while automo- ward are also supplied in this style of in- biles are standing idle on the streets, an strument. enterprising concern has developed this Many electrical instruments can be fur- auto parking light. This lamp is attached nished, when desired, with black dials, the to the rear fender and takes the place of figures, scale, and pointer being white. the regular head and tail lamps when the The comparative illumination on black and car is not being operated. The 2- candle- white dial instruments is vividly shown by power bulb is said to consume only about Showing New Magneto for Fordson Tractor the acompanying illustration, which shows a quarter of the current the regular lamps nstalled on Engine. It Has an Impulse a white and black dial instrument mounted use. A 21/2-inch white semaphore lens is StArter, Giving Full Spark on One Revolution. side by side on a switchboard and illumi- furnished in front of the lamp and a red nated by the same lamp. semaphore lens in the rear. An "off" and on itself by lamp itself. a support which is braced "on" switch is installed on the brackets attached to the crankcase. The EIWIWIIWIERIIWIIIIIIIIII instrument is driven by a short shaft at A Small Cur- one end of which is an adjustable coupling rent - Saving and at the other two bronze bearings Electric Park- mounted on either side of a 16 -tooth ing Light for sprocket. This sprocket is driven by a Autos. Lamp silent Is Attached to chain from another sprocket at the Rear Fender. forward end of the camshaft. The silent Flashes White chain is protected by a guard which is pro- A h e a d a n d vided with an oil hole so that the chain may Red to Rear. be given an occasional oiling. The chain Comparative Illumination on Black and IJiWWIIVWWVWVWIIWIIWW l is easily adjusted. White -Dial Instruments 1266 ELECTRICAL EXPERIMENTER April, 1920 PopuLZT /-1.01TORIOREIY

By RSA EL M a L EW1.1 5 p M. A u Of Ib, ïJ. S. Nazal Observatory TO appreciate the beauties of a star- () bsezevnng The best general view of the moon, as light night get as far away from the many are aware, is obtained a few days heart of the city as possible. No ob- Heavenly Bodges after the first quarter, but the best time to observations of the heavenscan be study any particular marking is when it lies made thru slit -like openings between near the terminator, the line separating the rows of houses with. the glare of street light from the dark portion of the moon's lights in one's face and the smoke, dust and surface. The marking, crater or mountain haze of a busy city enveloping one on all or cleft, as the case may be, is then illumi- sides. Even such celestial jewels as Sirius, nated by a low sun and casts a long shadow, Vega and Spica shine with a pale and sickly which indicates the height and form of the light for the city dwellers. object. Lunar objects that stand forth beau- Get out in the open if you want to be- tifully when the sun is rising or setting come acquainted with the stars and choose, upon them sometimes entirely disappear moreover, a clear, moonless night, for from view under a high sun. The poorest bright moonlight blots out fully half of the of all times to observe the moon is at the stars that would otherwise be visible to the time of full moon, when there are no shad- naked eye. ows and all detail of the lunar markings is A good test of the "seeing" is the visi- lost in a flood of sunlight under vertical bility of the Milky Way. If you always illumination. view the heavens from the outskirts of a The most interesting views of the moon great city the Milky Way really means noth- from a popular point of view are those ob- ing to you, but if you have the good fortune tained with a six- or eight -inch telescope to be aboard ship .on a clear, dark, moon- showing the entire lunar disk in the field less night or on the western prairies or near of view. the summit of a mountain or at some farm Highly magnified views taken with the or country home far removed from the great reflectors and refractors show the city you will not fail to see at some hour moon to us piece -meal, for, as the mag- of the night a portion of this magnificent nification increases, the angular width of girdle of the heavens, the groundwork of the field decreases, and instead of a view of the universe, where suns are piled upon the entire lunar disk we get a "close -up" suns in riotous profusion and where the of a very limited portion of the surface misty light of the luminous nebulae leads showing great detail. into the dark caves, rifts and lanes pro- Venus in the telescope is a surprisingly duced by the non -luminous nebulae, the beautiful little ob ect if seen near its time whole giving us the impression of an elab- of greatest brilliancy, halfway between in- orate and intricate structure that reveals Mars: Region of Syrtis Major. Photos Taken ferior conjunction and elongation, when the workings of a Master -mind and over- at Yerkes, September 28, 1909, Showing it appears as an exquisite little crescent whelms us with feelings of awe. Changes Due to Rotation. Exposure 3 to 4 moon. With a magnifying power of forty - In attempting to explore the wonders of Seconds. five Venus appears exactly as the moon the heavens with an opera-glass some ama- does to the unaided eye when it is four days old, tho, of it shows teurs have complained that they could not Some have course, no dis- find Jupiter's four moons. This may be due complained also of the "danc- tinctive markings such as appear on the ing" of the stars when viewed thru a spy- lunar surface, the tither to poor observing conditions, as men- glass or for surface of Venus is tioned above, or to the use of a poor glass small telescope of greater power screened from our view by its dense at- or to failure to recognize these minute than an ordinary field glass. It is useless mosphere. to attempt to use any instrument more pow- points of light when visible. All four erful than a field Astronomers prefer to make their ob- moons will probably not be visible at once, glass or opera glass without a tripod or rigid mounting of some servations of Venus and Mercury in the as one or more of the moons will usually be daytime, for they are then higher in the in transit across the planet or occulted be- form. The more powerful the telescope the sky and the observations are not marred by hind the planet or eclipsed by its shadow. the disturbing atmospheric effects of re- Continued observing from night to night more carefully it must be mounted. Buildings for housing powerful telescopes fraction, haze and "boiling" that are will reveal the fact that these little bodies always greatest near the horizon. are actually revolving around the plant. are built, if possible, far away from street- car lines and railroads for the trembling Saturn is one celestial object that hardly With a telescope that was in some re- ever disappoints us. His rings are a source to a field glass of the ground caused by the passage of spects inferior modern Gali- of never - failing interest to everyone. To leo determined the periods of revolution of trains and cars affects the instruments. Telescopes of four inches or more in aper- he sure, they disappear from view for a all four satellites within a few nights of very brief period once every fifteen their discovery. ture are of little value unless mounted on or a stone or cement pier and housed in such seventeen years, when our line of vision a way as to be entirely free of the floor, as even walking across the floor would otherwise cause the instruments to tremble. Tem- perature and atmospheric effects must also be considered, and to equalize the inside and outside temperature and overcome the "boiling" of the atmosphere due to unequal temperature the astronomer throws open the dome of the observing room for some time before he expects to begin his observations. At most large observatories "visitors' nights" are a regular feature. Visitors to Mt. Wilson Observatory observe the great 100-inch reflector from a glass encased observing room that they may introduce no 'temperature effects upon the sensitiveness of this powerful instrument. There are certain celestial objects that Remarkable Photograph of Saturn, Taken to see thru a tele- November 17, 1911, with the Sixty Inch nearly every one desires Telescope of scope. the Mt. Wilson Observatory.% Shows It as in a the Moon and Sat- This It Appears Powerful We all want to see Reflecting Telescope. An Interesting Telescopic View of the Planet urn's rings and some of our near neighbors Neptune with Its Moon. The Little White in the solas system, as well as some of the Spot Near the Large One Is Neptune's Moon. most interesting objects that lie many light lies directly in their plane, but such dis- An Unusual Photograph, as the Little Satel- the great nebulae and the appearances are comparatively rare and, lite Is a Very Difficult Object to View, Even years away, Thru a Large Telescope. globular star clusters and the double stars.? even at such times, we cannot fail to be in- April, 1920 ELECTRICAL EXPERIMENTER 1267

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIG At Left- Great. Photographic Neb- Deltaula Near Scorpii. Pi and Photographed by Mr. Barnard with the Bruce Tele- scope. Exposure 8 Hours and 45 Min- utes. One of the Most Beautiful Sights in the Heavens.

111111111111111111111111111111111111111111111111111111111111 At Right Encke's Comet, Taken- at the Yerkes Obser- vatory, October 29, 1914. Note the Great Lengths of the Star Trails, Which Indicate Rapid Motion of the Comet. This Comet Is Noted for Having the Short- est Period of All Known Periodic Comets, Three and Three - Tenths Years. At Its Brightest, It Is a Faint Telescopic Object, Showing no Trail.

terested in his belts and his moons and the the . human eye. All the wonderful detail the coarser globular clusters are wonderful pronounced flattening at the poles, which brought out in the photographs of the objects in the larger telescopes. With small Is then particularly noticeable. nebulae and star- clusters is the result of three -inch telescopes it is difficult to make Jupiter also delights us all with his con- several hours of photographic exposure. out the stellar nature of even the coarsest stantly changing belts and varied coloring, The Great Spiral Nebula in Andromeda, of the star clusters. and the phenomena of his four historic the Trïfid Nebula and many of the wonder- Double and multiple star -systems can moons that show up so beautifully even in ful double armed spirals with which we are always be found even with as modest an the small telescopes. familiar thru their photographs show up instrument as an opera glass, for these Mars in the telescope is usually a disap- quite disappointingly in the telescope be- systems abound in the heavens. At a con- pointment to every one, and the astronomer cause they appear so extremely faint to the servative estimate at least one out of every never presents him as a show object ; irs human eye. four stars belongs to a physically connected fact, he prefers not to show him at all Star clusters, as well as nebulae, appear system composed of two or more stars re- sinless you are prepared beforehand. The at their best photographically. A few of volving around a common center of gravity. Martian disk is small, for Mars is One of the tests of the power of a a tiny world after all. Its surface telescope is its ability to separate is less than a third that of the earth, close double stars. A six -inch tele- it must be remembered. To glimpse scope will separate a double star into the Martian canals one needs a its two components that appears as trained eye and the skill in observ- a single star in a three- or four -inch ing that only comes after long con- telescope, while it will in turn show tinued practise, as well as excep- as a single star a close double that tionally fine atmospheric conditions, can be separated by a telescope of such as are not usually to be found greater aperture. on visitors' nights at the observa- Some double stars are so close that tories of our large cities. no existing telescope is powerful It must be remembered that the enough to separate them, tho the maps of the Martian canals that shifting of spectral lines will reveal most of us have seen are the results that a companion star is present. of years of painstaking observations Such double star systems are called made under superlatively fine observ- spectroscopic binaries. ing conditions, and that only a small The wider doubles are frequently proportion of the total number of of beautifully contrasting colors, such canals have been seen at any one as green and red or blue and gold. time. A canal may flash forth dur- Many of these gems are visible in ing a moment of exceptional seeing the smallest telescopes and they are and then be dimmed by Martian among the wonders of -the heavens mists or terrestrial haze. Even the that every one will want to see. chance observer will note the snow Often the faint companion of a caps, however, and the most con- brilliant star will be invisible in small spicuous surface markings. telescopes because of the glare of The outer planets, Uranus and light from its bright companion. Neptune, are so far away that they Such is the case with the companions are of little interest even in the large of Rigel and Antares. telescopes. Close satellites of the planets In delving into space beyond the Jupiter, Saturn and Mars are also greatest interest to difficult to find, not only because solar system, of they must, all are the star clusters and nebulae they are small, but because and the double and multiple star always be so close to the planet that systems, as well as the many won- they are dimmed by its light. For derful regions of the Milky Way. the same reason our terrestrial Aside from the Great Nebula in planets are invisible at the distance which is, indeed, a wonder- of the outer planets. Orion, Most. Interesting of All Comets (Morehouse ful object in the telescope, the nebu- One of the Comets are not interesting objects Comet) Because of the Sudden and Unexplainable view telescopically, as they are lae are. on the whole, disappointing Changes in Form and Brightness That Were Con- to when observed directly. Here is one tinually Taking Place. The Telescope Was Kept extremely faint. No extended sur -; Pointed on the Comet While the Photograph Was face, such as the disk of a planet or instance in which the photographic the Star Images to Trail of the cumulative Being Taken, Which Caused a comet can appear brighter tele- plate, on account Across the Plate. Taken at the Yerkes Observatory, the naked effect of light, is vastly superior to October 15, 1908. scopically than it does to 1268 ELECTRICAL EXPERIMENTER April, 1920

1IIIiIIIIIIIIIIlil1111i11111111111111111111111111111111illlllllllllllllll At Left The Bruce Telescope- of the Yerkes Observatory, Showing the Thre0 Objectives by Means of Which Different Sized Photographs of the Same Regions May Be Photographed Si- multaneously. Magnif- icent Photographs of the "Milky Way" Were Taken by Mr. Barnard with This Instrument, Temporarily Located on Mount Wilson, Cal. The Plate Holders Are Placed at the Eye -End of the Telescope.

1111111111111111111111111111111111111111111111111111111111111111111111 At Right -A Universe of Suns: The Great Star Cluster in Hercu- les (Messier 13). Dis- tance from the Earth Estimated To Be 37,000 Light Years. Photo- graphed with the Six- ty -foot Reflector of the Mt. Wilson Observa- tory. Exposure 11 Hours. This Is Visible to the Naked Eye as a Faint, Hazy Patch of Light. In a Three - Inch Telescope, Its Stellar Nature Can Hardly Be Distin- guished.

1111111 N 1 111111111111111111111111111111 i 111111111111111111111111111111 i

eye, for altho the increase in light is pro- excels the photographic plate in catching One of the most interesting of all comets portional to the square of the diameter of fleeting glimpses of fine detail and in utiliz- was Comet the lens, the magnification Morehouse (1908), which, tho of the object by ing the rare instants of perfect seeing which never bright, exhibited some very striking the eyepiece spreads this light over a greater occur from time to time in all localities. surface phenomena. Its brightness changed from and the total amount of light re- Photography is far more valuable for time to time in a most ceived by the eye is less than when the ob- cometary erratic manner, and work than in delineating plane- the material that formed the tail at times ject is gazed at directly. tary features. appeared to The total amount of light received from be swept aside by unseen forces In spite of the fact that a comet is mov- or driven from the head with unaccountable the stars, however, is greatly increased as ing rapidly thru the solar system, valuable rapidity. It may the diameter of the lens increases, because photographic be considered one of the exposures of even several most mysterious comets that has ever ap- they appear as points of light. The bright hours' duration can be obtained by stopping peared. Many excellent stars can be seen in the daytime in the tele- photographs of this the clockwork of the telescope, which keeps comet were taken which prove the pecu- scope and millions upon millions of stars the stars immovable in the field, and allow- liarity of its behavior. invisible to the naked eye can be seen in the ing the stars to trail across the field while Of telescope. Many more special interest this spring will be the millions that can- an observer keeps the telescope pointed on apposition of Mars, which not be seen by the eye, even with telescopic the comet will occur on thruout the time of exposure by April 21. Mars' nearest approach to the aid, can be brought out by the cumulative means - of the cross- wiresin the finder of earth will take place a few days later, on action of light upon the photographic the telescope or by some similar means. April plate. 27, when it will be about fifty -four Wonderful photographs of comets have million miles from the earth. In 1922 and Photography is of little value in study- been obtained by such methods and these 1924 the distance ing in detail surface markings of plan- will be even less. the are of great scientific value in that they Any one may find the ruddy -hued planet ets on account of the rotation of the plan- afford indisputable evidence of the changes at that time ets on their axes, which makes long photo- very readily, as it will be the in the form and general appearance of a brightest red star in view in the evening. graphic exposures impracticable. comet that often take place with startling At the time of The Martian canals have lately been pho- apposition Mars will be suddenness. almost as bright as Sirius, the brightest star tographed at the Lowell Observatory, and The speed with which the comet is mov- in the sky, which Dr. Slipher's wonderful photographs of will disappear below the ing can be judged from the length of the western horizon very. early in the evening Jupiter give unsurpassed general views of star trails produced during the exposure. by the last of April. the Jovian markings, but all the more deli- At the same time Photographs of comets are of great value Mars will appear in the eastern sky shortly cate changes in tint and shade of the mark- to any one interested in researches into the after ings of Jupiter, Saturn and Mars sunset and will be on the meridian at and, in causes of the remarkable and unaccountable midnight. Jupiter will also fact, of the lunar markings as well, can changes be seen just in the behavior of comets that are west of the meridian at sunset and will not be caught only by the human eye, which continually occurring. set until after midnight. Ilp Trneaa RO helrfr0lrafl On The PrObEelms OT RadIlOacavIlay the first Silvanus Thompson In Memorial portunity for looking back with some de- on the ionization of gases, electrons, the Lecture, delivered before the Röntgen So- gree of perspective over the ground covered diffraction of X -rays by crystals, Ernest R. and, most ciety Sir Rutherford, F. S., re- during the last twenty years. important of all, the phenomena of radio- viewed the various lines of scientific inves- Undoubtedly the discovery of this new activity, which was an even more direct tigation opened up as a result of the dis- type of radiation marked the beginning of consequence of the discovery covery X -rays. Iii a to of X -rays of tribute the first an epoch in physical science and had than the work on the electron. The se- president of the society, in whose honor the brought about a revolution in ideas of the quence of changes in uranium, thorium, and lectureship was instituted, he mentioned nature of matter and electricity almost as actinium had now been followed out, not, that on the morning that the late Silvanus marked as that produced in biology by the indeed completely, but in the main part. No Thompson read of Röntgen's discovery he theory of evolution. The two decades from doubt there would nightfall still be in the future set to work, and by had succeeded 1895 to 1915 had been a period of pioneer considerable developments as the result of in producing what was probably the first advance over a new and fertile territory, investigations of the multiple transforma- X -ray photograph taken in England. The with the almost daily discovery of inter- tions of the atom, but as a whole, apart outbreak of war, Professor Rutherford esting facts and the gradual unfolding of from a few outstanding difficulties, like the said, had caused an almost complete stop- fundamental ideas. The directions of ad- origin of actinium, the transformation of page in the great tide of advance in pure vance which had been stimulated by the radioactive bodies was fairly well under- cience, but the lull afforded a suitable op- discovery of X -rays included investigation stood. 1269 April, 1920 ELECTRICAL EXPERIMENTER 66 99

(CONTINUED FROM THE MARCH NUMBER) MENTION. THIRD HONORABLE MENTION. a second, pictures of this nature are easily SECOND HONORABLE obtained. I wish to say that the peculiar effect re- The effect obtained in making motion The movie camera gives the same effect, produced on the sample piece of film pub - pictures of the rabbit undergoing the except that there are sixteen pictures per lisht in the December issue of the ELEC- corona discharge from a high frequency second in the standard machine, therefore TRICAL EXPERIMENTER was probably caused apparatus is due to the fact that the ex- the camera must have been running at a by the distorted curve of the primary alter- posures are made without reference to the speed synchronous to a harmonic wave- nating current which was probably operat- intermittent appearance and disappearance length developt when the discharge took ing at commercial frequency. of the corona discharge. place. C. SIMONS, A distorted curve is considered as a re- In a high frequency set the secondary HAROLD voltage and current rises to maximum and Elec. (R. O.) U. S. N., drops to zero value in a rapidly succeed- Frankford, Mich. ing train of high frequency waves for each 2 J 4 S 6 7 discharge of the primary spark gap. That is, the frequency may be 200,000 cycles per second, but these wave trains are split into A groups with a wave envelope of a shape b determined by the frequency of sparking . á . \- and the damping in the circuits. --Ce, A motion picture camera operating at a f rate of sixteen exposures per second with r=---a------s-K_------each exposure lasting, say, .01 second, will snap the corona in the different stages of The first five ex- ,, its changing values. Harmonics Enter Into the Solution of the posures on the length of film were made "Rabbit Puzzle" by Mr. Simons. One %n/rcyc% when the corona was at a value below its maximum, the sixth exposure occurring at the exact instant it had reached its maxi- FIFTH HONORABLE MENTION. mum value in one of its recurring cycles. Diagram to Accompany Mr. Coffman's Ex Were the rate of exposure and spark dis- As everyone knows who is familiar with planation of the "Mysterious Rabbit." charge kept at the same rate a perfect pic- alternating current on open circuit (such ture would be obtained at regular inter- as the poles and secondary windings of an high frequency induction coil constitute) sultant of a sine curve of the same fre- vals. with curve, combined THOS. W. BENSON. the poles are electrified alternately quency as the distorted and negative sign, one with a number of other sine curves of a 3722 M St., charges of positive of the re- pole being positive while the other is nega- higher frequency. The shape Philadelphia, Pa. of two hundred sultant curve depends on the features of tive. With a frequency thousand the change in sign of the charge design of the circuit. The sine wave of MENTION. that the as the distorted wave FOURTH HONORABLE of either pole occurs so rapidly the same frequency to the unaided eye to be is called the fundamental wave, and the discharge seems To explain this strange phenomenon, it continuous. higher frequency components are called used the resultant of is assumed that the spark-discharge The fact of the matter is that the dis- harmonics. Practically highly dampt order, also the speed the fundamental and a limited number of was of a charge is not continuous, but approaches a of the camera at the time happened to be pole under observation is harmonics will represent any distorted to one of maximum as the accuracy. running at a speed, synchronous charged with electricity of one sign at its wave with sufficient the many harmonics of a wavelength de- highest potential ; dies down and disap- The actual shape of curves is deter- velopt by the frequency of the spark dis- or by pears with the lowering of this potential, mined by means of an oscillograph charge. is almost In practice the prob- only to reappear when the pole some other method. this be true, then each picture, begin- with electricity of the lem is usually that of splitting up a given If immediately charged ning at the top would not necessarily be opposite sign at a rising potential. distorted curve into the fundamental and but the ability to distinguish taken of the next wave of the train, Thus it will be seen that if a camera harmonics, and next in their order of the harmonic. at a glance the presence of prominent har- the with a fast working speed were trained monics in any distorted curve can be at- It must be understood that the harmonic upon the rabbit (in this case constituting tained only by practice in drawing different is moving constantly with the frequency part of one pole of the machine) and the fundamental waves and harmonics and add- of the wavelength developt by the spark film exposed at the time that the electric ing these algebraically. In making such discharge. charge was changing signs (that is, when drawings the maximum value of the har- In this case the camera shutter opens there is no discharge), the film when de- if exposed monics should be taken at less than the only when the harmonic is in evidence ; that velopt would be blank, while maximum value of the fundamental. is, there is no picture taken except when at the time of maximum discharge the re- in picture number By referring to the photo of the film, the harmonic covers some one point of the sult would be as shown we may draw a resultant curve which will discharge wave -train. six. be distorted as can be seen. The resultant To illustrate this, the full lines in the As the moving picture camera has a curve is shown in the illustration. By be- drawing show the oscillations of only one "frequency" of approximately sixteen, and ginning at the top of the film and going spark discharge, and the broken lines show the electrical discharge a frequency of two down it can be seen that the power of the the harmonic position relative to the open- hundred thousand, the exposures would be primary inducing current gradually in- ing of the camera shutter on a spark dis- made at times of different degrees of dis- creased, and then suddenly flasht up to charge, that is, the first picture in the il- charge. maximum power when view six was taken. when the har- Thus exposure number one was made lustration would be taken a The numerals in the accompanying illus- as shown at C when the discharge was approaching monic was in a position two was made as the tratibn represent the time at which the re- in the second taken when the minimum. Number By analyzation the drawing, of the charge was still lower spective views were taken. again crost a wave -train or at potential resultant curves, it is proven that harmonic than the potential of the charge photo- of the D, at a point E, the fourth it consists of the fundamental wave b a point the third graphed in number one ; numbers three and the second and fourth harmonics c at a point F, the fifth at a point G, the and four are photographs of receding and d, respectively. sixth picture would be taken from the first potential, while in number five the ex- frequency Altho the current in the high frequency rush of current in discharging or at a point posures of the camera and the A, the seventh and eighth would be taken of the electrical machine again commence secondary circuit was oscillating at an ex- is compared with at a point G also or even later if the time- to be in synchronism, and the result tremely high frequency, was made just as that in the primary circuit, the power of length of the wave -train was greater. that the sixth exposure the discharge was at its maximum bril- the same at any instant was dependant I have made many photographs of spark eight the pri- liancy, while numbers seven and upon the power of the current in discharges, sometimes obtaining no picture at times of discharge of at that instant. again were made mary at all, and never any two of the same lower potential. RAYMOND NOBLE COFFMAN. strength or density. FRANK L. HEYDON. 105 Burt Ave., By using a speed camera with a shutter Ponca, Neb. Newark, Ohio. speed of One, three or four hundredths of (Continued on page 1317) 1270 ELECTRICAL EXPERIMENTER April, 1920 ZEDECeZIA-: C]h e mpezilame neo By iPR©F0 FLOMDD Lo DARROW

illlllllllIIIjIjlllmi. eI ,11;, Left - Making Phosphine Rings Is an Extremely In- teresting "Chemi- cal Stunt," Which Wilt Please All Those Who Have Even a Small Lab- oratory. The Gas Rings Arise in the Form of Beautiful Concentric Circles. Right- Generation of Water Gas Is Here Readily Dem- onstrated, the Gas Being Collected by Downward Water Displacement. Note Bunsen B u r n e r Quartet. The Set - Up of the Appa- ratus Is Clearly Depicted in Dia- gram, Figure 11.

911111111111111111111IIIIIII e illli I.,,muiJ FLAMES AND ILLUMINANTS. IGNITION OF GAS FROM AN EXTINGUISHED downward '-IE CANDLE. and thrust upward into it a object of experimentation in the lighted candle attached to home laboratory Light a candle and when a wire. The should not be it is burning hydrogen lights at the mouth of the amusement, merely. If well blow out the flame. Immediately hold cyl- that were a lighted inder with a small explosion, burning with the sole purpose, it would not be match in the rising smoke a half an almost colorless worth inch above the flame, but the candle the time and effort required. wick, when the vapor will immediately goes out. Upon withdrawing But the skill in manipulation, the knowledge catch fire and running back will communicate the the candle it is relighted at the mouth, of chemistry, the training in observation flame to the wick. showing that the and the interest To show this hydrogen itself is burn- in scientific work acquired on a larger scale arrange ing. The operation may be repeated in such practice are of inestimable a candle and Argand lamp chimney as a value. shown number of times before the gas is ex- It is well to remember, too, in figure 1 allowing for good ventila- that a century tion. hausted. This shows clearly that while the and a half ago when chemistry was in On blowing out the flame and ap- hydrogen infancy its is combustible it does not sup- most of the great chemical dis- port combustion. This is also true of coveries were made in home laboratories. many other gases. Therefore, in all the work make it the best possible, be sure you understand the chem- BURNING AIR. istry back of it and seek at every point to That either illuminating gas or air may gain increased skill in manipulation. be regarded as the supporter of combustion In this article is shown we shall consider the by the following experiment : chemistry of flames and illuminants -a most Fit a lamp chimney with a 2 -holed rub- important field of chemical investigation. ber stopper carrying a glass elbow and a Perhaps, we had better start off with the straight glass tube as shown in figure 3. fact that to produce a flame requires the The straight tube should be about 10 milli- union of tv o gases or vapors. Red hot meters in diameter. On the top of the coals glow but there is no flame. Likewise chimney place a piece of asbestos board the burning of iron in oxygen or the union with a small hole in the center. Now con- of sulfur and zinc dust produces light but nect the glass elbow with the gas supply no flame. and closing the hole in the asbestos board with the palm of the hand turn on the

Here Is Something New to Try on the Gas Company. Instead of Burning Gas in Air Do Both; Burn Air in Gas and Gas in Air- Simultaneously, Thus Obtaining Two Lights at the Cost of One. The Trick Lies in the Lighting and Piping Arrangements of the Apparatus.

plying the lighted match to the top of the chimney, the candle will be relighted. The chimney may be 3 or 4 inches in height.

TO ILLUSTRATE THE TERM "SUPPORTER OF COMBUSTION." A gas may be combustible and yet not a supporter of combustion. This is well il- An Extremely Simple Acetylene Gas Lamp lustrated with hydrogen. Generate a cylin- Whereby the Amateur Chemist Can Work at der of the gas in the usual way by the The Gas Flame Above Shown Coming Front Night. The Light Emitted Is Very Constant action of dilute the Bottle Is Due to the Fact That Gas Had and the Lamp May Be Turned Off by Simply sulfuric on zinc and collect Been Introduced Primarily and Later Shut Tightening the Pinch -Cock. The Embryo the gas over water. Off. Air Mixes With the Gas in the Bottle Is Until Chemist Here Seen Carrying on an Analy- Now as shown in figure 2 hold the cyl- Finally the Mixture Therein Contained sis Experiment by the Acetylene Lamp. inder of Is of a Sufficient Explosive Context to Go Off hydrogen in the left hand, mouth With a Loud Report. April, 1920 ELECTRICAL EXPERIMENTER 1271

of an cxplosir, mixture of gas and air. when the feeble flame strikes down into the ASbeS/os f/ame mixture and ignites it. The "striking back i- Goy of a gas stove or Bunsen burner is due to lLir Burning in almosphere of the same cause. i//uminalingçns Smoie /romain. guisGrd rande THE SAFETY LAMP. gniles !mm mkn Multiply the above explosion a million ana figes condie like the agoni times and you will have something effect produced by an explosion of "fire damp" in a coal mine. It will show you, too, the necessity for the miner's safety lamp invented by Sir Humphrey Davy a Gas century ago. The principle of this lamp is well shown Ugh/ it a candle with a cylinder of lirsf - by surrounding fig.3 /i0.4 fg. s fig. 2 le fine iron or copper gauze. Cut a sheet of . gauze 6 by 8 inches and roll it into a cyl- Igniting the Gas From an Extinguished Burning Air in an Atmosphere of Illuminat- Candle, Thus Lighting the Candle Again. inder and fasten it along 'the edges. At ing Gas. Two Lights are Noticed, One a.. the bottom place a candle, securing it in the Top of the Cylinder Burning in Air, the Above. Diagram Showing That Even Those position with wire supports. Other Inside the Cylinder Burning in an Gases Which Burn Can Ac: as Supporters of Atmosphere of Gas. Combustion in Which Case They Need Not Light the candle and hold the cylinder Burn. horizontally in jet of illuminating gas as The Layout for the Explosive Mixture Ex- periment. The Gas Supply Pipe and Cork shown in figure 5. The gas will be seen Is Removed; the Flame, However, Still Con- gas. Then light the gas at the lower end to burn inside the cylinder but the flame tinues to Burn. Why? of the straight tube, immediately remove will not communicate outside and the burner your hand from the cardboard and also will not light. This gauze may even be- The platinized asbestos may be prepared light the gas at the top of the chimney. come red hot without igniting the gas on by moistening a small quantity of asbestos Two flames will result, one at the top of the outside. So good a conductor of heat fibers with a few drops of platinum chlorid the chimney, which is the excess of gas is the gauze that the gas does not reach solution and igniting them in a Bunsen burning in air and the other at the top of its kindling temperature. A simple applica- burner flame. The chlorid decomposes and the straight tube, which is air burning in an tion of a physical principle, and yet it has finally divided platinum is left on the fibers. of illuminating gas. Thus air saved thousands of lives. atmosphere RINGS. is the combustible gas here and the illumi- PHOSPHINE SMOKE nating gas is the supporter of combustion. A BUNSEN BURNER FLAME. Arrange apparatus as shown in Figure With the air holes open at the bottom of 7. Fit a flask with a 2 -holed stopper carry- AN EXPLOSIVE MIXTURE. the tube a Bunsen burner flame shows two ing two bent tubes, one of which reache; Secure a 2 -holed Woolf bottle of two distinct cones -an outer cone of burning nearly to the bottom of the flask. In the or three liters capac- flask place a strong ity and fit the necks solution of sodium or with stoppers carry- potassium hydroxid ing glass tubes as and a piece of yellow shown in Figure 4. phosphorous, the size The straight tube of a pea. Connect the should be 10 or tube leading to the about flask 12 millimeters in bottom of the diameter. Connect with a gas cock and the glass elbow with drive out the air. To a gas cock, and turn- the other tube con- ing on the gas drive nect an 18 -inch length out the air from the of rubber tubing, in bottle. Light the gas the end of which is at the top of the inserted a glass de- straight tube and livery tube. Have then withdraw the the end of this tube elbow with its stop - bent up slightly and per, at the same time place it in a basin of turning off the gas. water. The flame will con- Your Own Gas Gene rator; Making "Water Gas." You Can Bottle I t and Use It to Your Now heat the continue to burn at the Heart's Content. tents of the flask and top of the straight as the solution begins tube for a few minutes and then seem to gas called the "oxidizing" flame and an to boil a gas will be given off which spon- disappear entirely. But do not conclude inner cone of unburned gas called the "re- taneously ignites on reaching the air. that nothing will happen. Wait, and sud- ducing" flame. ACETYLENE LAMP. That the inner cone is not undergoing AN denly a sharp report will occur and the mouthed bottle of one or be filled with a sheet of flame. combustion is very strikingly shown in the Obtain a large bottle will two quarts capacity, a large lamp chimney, effect is much following way : Thrust a pin thru a match In a darkened room the of wire gauze, one -holed more impressive. stick about a half inch below the head. small disc coarse of a Bunsen burner rubber stopper, 6 -inch length of glass tub- As the burning gas escapes, air enters Mount this in the top acetylene gas tip thru the open neck until the bottle is full and turn on the gas. Now light the gas ing, rubber connection, and observe that the match does not burn. and 18 inches of heavy aluminum wire. (Continued on page 1328) ; Gas Ave, To show that it has not burned turn off ty/nde pper the gas and it will be found that the match is perfectly good and can be lighted in the usual way. Another very striking experiment to /fire gauze . demonstrate this fact is illustrated in figure wrrtlindig 613 Je/ 6. Make a burner of a small glass funnel (ao//ame) coed/e I.6ine pmenls ,gas and over the top place a piece of fine cop- lrom/gnihhg per gauze. In the center of the gauze place a small heap of gunpowder or flash- light powder. Turn on the gas and light it by bringing a match down from above. The gas will burn but the powder will remain unignited. Slowly turn off the gas fi9.5 fig.6 and as the flame diminishes in size the e powder will ignite. The Plan of the Miners Safety Lamp Show mg That an Explosive or Dangerous Gas SPONTANEOUS IGNITION OF HYDROGEN. Will the Wire Cage, Vet Burn Inside Gauze Direct a stream of hydrogen from a Not Ignite the Atmosphere of Gas Surround- The Very Pretty Prosphine Ring Trick. The ing It. generator on some platinized asbestos. when Above Diagram Demonstrates a Stunt Whicl Demon -rating That the Inner Cone of the the asbestos will be seen to glow and pres- No Experimenter Should Refrain Frcm Bunsen Flame Is Cool. ently the hydrogen will ignite. Conducting. 1272 ELECTRICAL EXPERIMENTER April, 1920

THE CONSTRUCTOR °iyTw

Hom mad 11 -Volt, 6 -Cycle In .taction t®r y mai. PARUSER

ANY uses could be found for a to the stator slots. By using care and with tightly together but not so tight as to small single -phase motor which an accurate drill press or lathe drill pad spring them open where there are no bolts would connect up to an ordinary it might be possible to cut both a rotor and or rivets. The rotor core is similarly con- M 110 -volt lamp socket, and while stator lamination from one sheet of iron, structed, but the laminations are held on such motors are not high priced by making narrow separations at the cor- the shaft by two pairs of locknuts as well many Amateur Mechanics wish to build ners where the rotor faces meet the corners as %" bolts, insulated with paper and fiber them themselves, but are deterred by the of the stator poles. Otherwise separate nuts, which also act as posts to hold the difficulty of making or obtaining field and square sheets must be used for stator and windings in place. rotor punchings, for, unlike the direct cur- rotor laminations, requiring, of course, con- All the machine work must be completed rent variety, both the stator, or field mag- siderable more material. A saving could before starting the winding. In regard to the net, and rotor cores must be built up of be effected by making each stator sheet in bearings (Fig. 8 -A), these are cast in brass iron sheets or laminations. two parts, as per the dotted lines in Fig. 3, or bronze; heavy bar brass with bearing No originality is claimed in the main de- and "breaking joints" when assembling the bushings soldered or brazed in might also sign of the small motor to be described, but pile, but this would introduce a little more be used. The bearing yokes are separated an attempt has been made to lay out a strong reluctance into the magnetic circuit. Figs. from the stator core by cast iron, steel or and substantial construction not too diffi- 6 and 7 illustrate the method of making the brass posts, which also act as nuts to clamp cult to be built at home on a small screw - drilling jigs out of a scrap plate of half or the laminations together. There are several cutting lathe. The power of this little mo- three -eighths inch cast iron or steel. Care possible ways to drill out the bearings. One tor would depend to some extent upon the should be taken in laying out these jigs that would be to put an 11/32" drill thru the materials used and the workmanship and enough material will be left around the bolt holes in the core, spot the bearing care in making the windings, but it should edges of the sheets, after drilling, to allow yokes and then drill and ream them 5/16' . be serviceable for driving a fan, buffing of a smooth finish. To use the jigs, the Then put in the 5/16" bolts (Fig. 7 -A), insu- wheel, rotary spark gap, or various types square sheets are piled up to make a depth lated with shellacked paper and screw home of light machinery. Having but one set of of two inches, for both stator and rotor, the posts. Drill and ream to ;" a 2" windings upon rotor and stator, it is not when comprest; this would take about 68 length of steel shafting, drive it thru a hole self- starting and will not start under a full sheets of 22 -gage iron. After clamping or in a 2" hardwood block, place between cen- load, this being characteristic of all such bolting, by the corners, to a hardwood ters in the lathe and turn the block to a types of alternating current machinery. But board, the center hole is drilled and two diameter that would just allow it to be by using a tight and loose pulley or a simi- lines scribed exactly at right angles thru pusht into the bore of the stator (3/16 "). lar contrivance and giving the belt a sharp the center ; then the four 11/32 -inch holes Then put in the short bearing studs (Fig. 8) pull after throwing the switch, the motor in the stator and 5/32 -inch holes in the and bolt one of the bearing yokes in place. will pick up speed without difficulty. An- rotor are drilled, rotating the jig so as to Using the steel busht block as a jig, drill other crude but effective starting device is use the same hole thru it each time and tak- and ream the bearing yoke. shown in the assembly drawing (Fig. 2) ; ing care that the holes were exactly ninety Two angle plates (Fig. 9) are cast in iron this consists of a spool shown on the left - degrees apart. Then a pin is driven thru or brass for the motor base; these can be hand end of the shaft around which a heavy the half -inch hole of the jig and one of mounted on an angle plate on the face -plate cord is wound and the motor given a start- these holds the jig furthermore clampt to and faced to take the stator core ; one 5/16" ing whirl by a quick pull of this cord. the pile, and one -quarter of the holes bolt, also wrapt in paper, holds both in In regard to the laminations : field and drilled; the jig is then shifted thru a right place. rotor are built up of sheets of "stove pipe" angle and the process repeated, and so on The rotor laminations, as previously men- iron of about 22 gage, tho if regular trans- until all the holes are thru. With an accu- tioned, are held to the shaft by two sets of former iron or silicon steel was obtainable rate drill press the whole pile could be locknuts, one set of which have 1" flanges. a more efficient, as well as more expensive, drilled thru at once, but in other cases it Or two 1" washers and four S. A. E. r s" machine could be produced. Even tho these might be best to drill half of the plates, or nuts could be used. In any event, after sheets could be given a form simple enough a pile one inch high, at a time. The plates screwing up these nuts and their lock nuts to be cut out by hand, separately, with tin- are now separated, the pieces broken out, to clamp the laminations tightly, they are trees snips, this would be a formidable reassembled and the edges finisht to size turned down to finish dimensions and the undertaking, and the method decided upon with a file. Previously to separating a shal- shaft also turned to finish size. If done here is to cut out square sheets, pile them low hacksaw cut should be made across the previously to this, clamping the laminations up, clamp together, drill out along the re- pile at some point, to insure getting them might spring the shaft. Two grooves are quired outlines by means of a jig plate, back in the same position, and before returned, with sharp edges, to prevent oil then separate, break out the portions not assembling the outside corners are cut off working up into the rotor windings. A light needed and finish by filing and in the lathe. to make less work for the lathe. cut is also taken to true up the surface of Even this means considerable work, when The stator plates are then assembled and the rotor. Then the insulated 4" bolts are compared with the construction of a direct bolted to the lathe face-plate, with a hard- run thru and clampt by the fiber posts. current machine, but to partly compensate wood packing piece in between, centered up Figs. 10, 11.) for this the A.C. motor has no commutator, and bored out and the outside turned down slip rings nor brush holders, the rotor wind- to the given diameter. They must then be THE WINDINGS. ings being short -circuited. As seen in Figs. taken apart again and all burrs cleaned off Now for the windings. Procure a roll of 1 and 2, the motor has four poles, with four the edges to prevent making electric con- "armature" tape, wrap some around the stator coils, while the rotor has four wide tact between the laminations ; before the stator cores, tie it and cover with shellac. slots and also four poles, with no electrical final assembly each plate is given a thin The construction of the stator precludes the connection between stator and rotor. At a coat of shellac on one side and allowed to use of form wound coils; so enough wire frequency of 60 cycles the speed will be a dry. 5/16" bolts are used and each is for one coil is wound on a spool small little under 1,800 r.p.m. wrapt in shellacked paper so that when enough to pass thru the core, and the coil Fig. 3 shows the shape of the stator lami- dry it may be just driven into the 11/32" is wound by hand. A couple of split flanges nations and Fig. 4 of the rotor. By refer- hole without tearing the wrapping. This of very thin fiber could be slipt on each end ring to Fig. 1 it will be seen that with the bolt and rivet insulation is necessary for of the core and glued together, the splits rotor in the position shown the spaces, or the insulation of the laminations. Similarly, opposite, to act as heads for the coil. No. 22 slots, in the rotor, lie opposite the stator .ç, rivets are insulated and put thru the D.C.C. copper wire is used for the stator; pole faces, while the rotor faces lie next 5/32" holes. The plates should be clampt (Continued on page 1314) April, 1920 ELECTRICAL EXPERIMENTER 1273 Home-made A. C. MCMOT

rig.' f/9.2

r19.4 'et shee//ron serega

ill/nd/ag space f/g. 3 ta 'heel /roi? 65 re9e

fig. 5 /c/. 7 r 74 21- 34 - 13" fig.// regd. LOG/(nits /rd fibre Thread ix ZO SAE

Motor shaft ce sire' .1 /210' HZ 1-_ Fig 8 Carnage Boll CR.sfee/ 4 regd.. i

fig /2 r/g.7-4 CR. sire/ zregee

r/g. /0 Drill top 4 x CR "fee/ 4re9d fii9. 9 fig. 6-A 4 reqd brass E ePegif (Full Description Covering the Construction of This Alternating Current Motor on Opposite Page.) X1276 ELECTRICAL EXPERIMENTER April, 1920 ELectro-Monogma. sIlgn TOT the Boys when lamp No. 8 is lighted, the whole Bock front trough indicated by No. 8 is lighted. When various combinations of these lamps are lighted, different letters may be formed. The entire alphabet 4 U2 zY 1°- and all of the numerals may be formed with this monogram. The wiring diagram is shown on the back of the monogram. The heavy line is a continuous wire which is attached to one side of every lamp. This line goes to one side of the battery or power line. Now one wire is run from the other side of each lamp to the switch -board terminals shown on the left of the board in the drawing. The lamps numbered 2 and those numbered 19 may be connected to one wire, as there is no letter that requires the use of one No. 2 lamp without the other. The same holds true in the No. 19 lamps. That means that we 2 have nineteen wires to connect to the s switch -board terminals. Only twelve wires 7 are shown in the drawing for the sake of simplicity. IIi111P111151111M111 On the switch -board the nineteen wires 1111111111111I1P.1I. are run across loosely until the letter 11111111111IIIIIIIIII11111111111111/1=111=IIIIIISAMII groups such as T, P, I, F and the dash have been tapt. They may then be formed into a cable to give plenty of room on the board for the letter groups. 111111111111 111111111 il 11111 1111111 11 1111111 11 By tracing out the wires in the T group, it will be found that the lamps to which these wires are connected will form the letter T when lighted. The same is true .9 of the P, I, F and dash groups. The wires forming the letter groups are stretched across bridges about a quarter of an inch high and fastened at the ends. The bridges should bb made of wood or other non- conducting material. The portion of the +1 1_ wires between the bridges should MA/MS be bared. Now a wire is run from the source of current to the center of the bottom of the Something of Interest to Every Young Electrician -an Electro- Monogram Sign Which Is board and there a single -wire is Easily Constructed at Small Cost. cord attached. At the end of this cord a T- shaped metal is HERE, boys, is a signaling outfit that tion of the monogram. In case you make bar placed. The handle should be you may use at night, spelling out, a small size, a wrapt with tape or otherwise insulated if cigar box of proper pro- strong current is used. The one letter at a time, any message you portions is just right. It should be slightly bar must have desire to send to your "pal" across the longer than it contact with the wire cord. When the bar is wide, but the proportions is placed across in street or over on the next avenue. No do not need to be exact. the bare wires any let- code is necessary. You merely place a me- The light portions of the monogram ter group, the lamps to which those wires tallic bar the are connected will be lighted, illuminating across groups of wires and shown in the picture are troughs. Thin the desired letter. monogram, which contains electric lights, wood or metal may be used in making forms the desired letters. these troughs. They should be about as The letter groups may be arranged in You may construct the monogram any deep as the length of the lamps used in rows in alphabetical order or after the size you desire. A small one may be oper- them, allowing a glass front to be placed manner of a typewriter keyboard. When ated with batteries, or a large one may be on the monogram if desired. Each trough the operator gets accustomed to the posi- connected with the 110 -volt lighting circuit is furnished with a lamp. as indicated by tions of the letter groups he will be able of your home. the numbered circles. The troughs are to spell out messages with great rapidity. A shallow box is used in the construc- painted white to form a reflector. Thus Contributed by ALTON D. SPENCER. Men5urrIlng ELectirIlc CourpeEra WIltra .ahe Eye By C. A. BRIIGGS AWASHINGTON scientist at the against the bright background thus formed first bulb is heated by an electric current Bureau of Standards has devised an by means of the eyepiece, which is provided controlled by a rheostat. The value of this ingenious arrangement whereby it is w th a color screen so that the observer is current can be determined, as indicated in possible to measure the amperes of elec- working always in light of one color. The (Continued on page 1324) tric current by means of a sort of photo- i meter. In his scheme the brightness of a hot filament is matched against a bright Rheostat Ground gloss Lens Current to be measured background. This may have an applica- screen ,. tion to alternating current work, and particularly to wireless work where it has been always necessary to get some means where- Ih aiái\ \\\ììoiiüiiaaiiaiiaiaiaoiaiiiHiiaaidìì\ì by the value of an alternating or high -fre- , ., to its equiva- %; quency current can be reduced lent direct current. The method can be understood by reference to the accompanying diagram. The 7o potent/envier electric bulb at the closed end illuminates Eyepiece a ground glass screen the image of which Co/or screen !E is thrown, by means of an achromatic lens, s on the filament of the second bulb. The Arrangement of Electric Lamp Apparatus for Measuring the Current Strength By Match- filament of the second bulb is viewed ing the Brightness of a Hot Filament Against a Bright Background. April, 1920 ELECTRICAL EXPERIMENTER 1277

2 to It -Great Care Must Be Taken in Removing the Plates from a Storage Battery, So As Not to Damage the Lead Paste Filling. -See That the Insulators Between the Lead Plates are Perfect and Not Cracked Or Broken. 3 -The Terminal Connections May Be Soldered Or Fused By Current Obtained from Another Storage Battery, Using a Pointed Electrode As Shown.

Q to Tm ° a3 miz tin By HENRY KLAU SINCE automobiles have become so explained later) is allowed to flow until the intervals of one or two months to keep the popular many profitable occupations cells gas freely, then continue the charge Sp. Gr. up as long as it is not in use. A and side lines are afforded for rebuild- for 6 hours at the finish rate (in this case repair station should make a specialty of ing and adjusting their various parts. 41/2 amperes with about 5 lamps con- storing batteries for auto owners. If the This is especially true of storage bat- nected). Never hold a match near the vent batteries are neglected and allowed to tery repairing and recharging. Most gar- holes while charging as the products of of the plates be- one of the cells freeze the active material ages in small towns are not in a position or electrolysis explode. If fall off. The table apart and bother has become short -circuited or for some comes spongy and will have not time to take them gives the freezing points of various den- with them, so they send them away to some other reason is below the rest, it should be larger place to have it done. Any one with charged separately until it is up with the sities. 1150 Freezes 20° above Zero Fahr. a little experience can do this and make a handsome profit be- 1180 " 0° 1215 " 20° below " sides. It is the object of this I/ briefly the main 1.250 60° " paper to explain circuit a 100 points to be observed in the ap- -l'1%irped On a 110 Volt Con/act-of 1 Am- plication of this work. Watt lamp draws nearly equipment needed corn- Warped ?kite Plate pere and a 50 or 60 W. / Amp. The e When these size lamps are used prises a syringe hydrometer, volt- %nsu/afor home- BOTTOM VIEW Of-SET for the charging resistance (110 ammeter, welder (electric is easily test clips PLATES. WARPED V.) the current flow made), saw, blow- torch, Of ONE /S connections for lead covered, pincers, sulfuric calculated. The (can this outfit are shown in the dia- acid, solder, distilled water Current forget to connect be made in the still shown), gen- gram. Don't Leads the positive side of the current erator or rectifier and lamps for /ips of charging. TestC supply to the positive terminal repairing could Lamp OE OK* to Hook on the battery. Quite a number of While battery be connected in be done without a charging ap- -C batteries can /Desistance Switch Batteries series and charged at the same paratus, it would be very incon- put venient to carry them to a garage CHARGING CIRCUIT time. If you have test clips them on the ends of the charging or service station to be charged positive every time after they were fin- terminals, painting the are red; also provide a few wires ished. Many experimenters a test clip equipt with D.C., or, a rectifier about a foot long with on each end. With these a con- can be purchased from any elec- instantly trical house. It will pay well to nection is easily and the money ex- made. install this because comes pended is soon made back on it. Very commonly a battery in Fireor5tove in that has one or more cells When a battery is brought a the first thing to do is test the SIMPLE STILL which will not raise even after show from e day or two of continuous charg- voltage. If the cells is usually 1 to 2 V. each they probably need Useful Hints On Storage Battery Repairing. Top -How Plates Be- ing. This condition come Short -circuited By Sulfating, Over -discharge Or Over -re- caused by warped plates which only charging. Next draw enough Lamps electrolyte from each cell sepa- charge. Center -Charging Circuit with Lamp Bank. The have worn thru the insulators are of the Voltage Rating of the Line Potential. Positive Line each other. Such a rately into the hydrometer syringe Goes to Positive Terminal of Storage Battery. Bottom -Simple and touch to float the hydrometer, take Still Made from Kettle and Large Bottle for Distilling Water for cell, obviously, cannot be charged it back again in Storage Cells. Never Use Spigot Water-it invariably Contains as the current goes thru the point reading, and put Sufficient Mineral Traces to Sulfate or Disintegrate Your Battery is the same cell. The table below Plates. of contact. The only remedy shows the relative strength of the to take out the plates and insulate come together. A battery at the various readings : others and then connect them all in. Some the places where they 1250 80% strength of battery times a cell lags behind because the electro- whole new insulator can be put in, or, a 1225 60% O IS " lyte leaks out of a cracked jar, and every strip an inch wide can be put in from top to o o 1200 40% o time water is added the Sp. Gr. becomes bottom where the pressure comes. These o O 1175 20% " less. This is taken up later. If the Sp. insulators may be obtained from any house 1150 exhausted. Gr. does not reach 1275 or over after 6 selling storage batteries. (Diagram shows charged battery should have a Sp. hours of charging at the finish rate continue putting in separators.) A fully there is no increase. If a As increase in age storage cells de- Gr. of 1.275, or 1275 on the hydrometer, at this rate until they shows a battery has been neglected for a long period teriorate. In a storage battery the active but it sometimes occurs that one grids. This is density of 1300 or even 1325. it may take several days to bring it up to material falls from the capacity. Never add acid to raise the den- hastened where they are used on an auto- The charging rate will be found on the sity until the battery is fully charged. If mobile, because of the jolts they get. The lead name plate tacked to the case. Here is it must be added it should have a Sp. Gr. of more material they lose the less charge they an example: 1210. will hold. It is the positive element that Start 131/2 Amp. Finish 41/2 Amp. A battery set away for the winter or almost always falls out first and a new case a current of 131/2 amperes standing idle for any length of time should set of these plates will often make a good In this 1313) (about 14 -100 Watt lights in the lamp bank first be fully charged and afterwards at (Continued on page 1278 ELECTRICAL EXPERIMENTER :April, 1920

E:b-4- , dllxfi1 By H. WIINFEEFioD SECOìt3 No. 6- ERECTING MOTORS AND SHAFTING

THE erection of dynamos and motors face width. In this case the string is ap- string, which should be placed exactly thru is always a matter requiring extreme plied as shown at B, in the usual manner, the Centers of the bearings in the end hang- care, particularly when it comes to and by means of a rule the difference be- ers, as becomes evident. properly Of course the string and exactly alining the tween the two pulley widths is divided up must be carefully checked up with a good pulleys on the motor and on the shaft proportionately. For instance, if the larger spirit level, so that it is in a perfectly level which it is to drive. The leveling of the pulley has an 8 -inch face and the small plane. The shaft hangers are usually held pulley a 6 -inch face, then if the two are to on ceiling beams by means of lag bolts. be alined, as is most always the case, then one inch space should be allowed on each side of the small pulley face when it is left./ Leve/, checked by a cord held on either side of lewiig and the large pulley, as becomes clear upon :s examining the diagram. If the method of lining up pulleys with tle.adng the cord is not quite clear, a glance at Fig. 470/3 1 -C will make it so. Here it is ir, seen how a ''.AIIInglinn111nIY11nnN111111I cord is past, as nearly as possible, across 1111,11111111141 IIIIIIIIIIi the two diameters of the respective pulleys. Where the shaft projects thru a pulley, then level the cord is simply pulled taut a little to one side of it, which gives exactly as good re- /x sults as if there were no shaft projection, and the string past exactly over the diam- -C- fig s -D Diagram Showing How Motor and Shafting eters. The length of the belt, which is to - Pulleys Are Lined . Up for Belt Drive by connect the pulleys is usually measured by The Leveling of Motors and Dynamos Is Not Means of a String or Chalk Line. If One means of a strong, non -stretchable cord, Always the Easiest Proposition Imaginable. Pulley Is Narrower Than the Other, Then it Several Ways of Leveling Is Centered as Shown at "B." past over the two pulleys or else by means Up Electrical of a tape measure. Machinery Are Here Shown. base of the machinery, as well as the level- If the belt is to be a very exact fit, LEVELING DYNAMOS AND MOTORS. ing of the shaft and are also very important of the endless variety, then the tape The leveling of dynamos and motor matters which we shall here give our con- measure should be a steel one, so as to frames is not always the sideration. give a very exact reading. easiest task im- Most all mo- aginable. This is particularly true in the Referring to Fig. 1, A, B and C repre- tors, however, are fitted with belt- tighten- case of small motors sent different phases ing and dynamos having of the art of alining screws on their base, so that quite a round or special housings, as shown two pulleys, such as those on a motor and little variation is allowed for up at tightening Fig. 3 -A. An idea which can sometimes be on a line shaft. At Fig. 1 -A, the funda- the belt, once it is put into place. brought into play, for such machines, is to mental principle followed in lining up two LEVELING SHAFTING. have a leveling pulleys of equal face cradle of the form shown, width is illustrated. The leveling of shafting, whether large and which may be adjustable A strong cord or chalk line is held or small, is an important for different across affair, if the sizes of machinery, which can be placed the two faces of the pulleys so the best efficiency and quietest so that running results as to rest on the shaft on both ends of the string shall touch at the four points marked are to be obtained. Figs. 2, A, B and C "X." Usually motor. The two lower feet of the leveling two men do this, but if you show some useful wrinkles in leveling cradle should have to do this alone, as will happen shafts. The usual method have V- shaped slots in them. occa- for ordinary The level is then placed on top of sionally, then the string may be tightened work is to employ a first -class steel level the around the pulley or - cradle, as shown.. In other cases there otherwise secured at preferably one having a V- shaped bottom is its highest point, when you can easily pull -and the shafting should be turned into often a sufficient amount of ma- the string taut and bring it gradually into several different positions, so as to get a chined surface on the base of the motor line with the lower base of the top pulley, mean average on the level readings, and so that it can be leveled in the necessary and then move the motor to be mounted into also the level should be placed on several two directions, i.e., at right angles to one position, so that its pulley face will be in points along the shaft while making the another at the points marked Xl, X2 and perfect alinment with the cord. measurements, such as those indicated by X3, or on both sides, and front and back Care must be taken to see that the cord X, X, X. of the base. is not allowed to assume an angular posi- A unique suggestion to help in simplify- In some instances tion such as shown, in a greatly exagger- ing the leveling of long shafts, or, for that it is possible and per- missible on a small ated manner, by the dotted line E and F. matter, short ones, is shown at Fig. 2 -B.' motor or dynamo to In some cases the two pulleys, that is the Two boiler gage glasses or other suitable level it close enough by placing the level driver and the driven, are not of the same glass tubes are hooked up with a length of proper on the face of the pulley, as shown rubber garden hose or rubber tubing; this (Continued on page 1323) / /// // // Y / // // // // /// / / / /, q // // //H/ /f Y // // / // / / / / // / // /// / / // / / / / // // // / // // / / / / is then filled with water, the water not / quite reaching the tops of the gage glasses. Xi_ -A- W The free ends of the gage glasses are fitted ,.. v lallomskr with hooks, which may pass over the shaft Shofl lo ee /ere/ed "eV is used and hold it in position in the manner shown.

, This method is quite exact indeed, as it is .-----slofi must measure some---- I1 well known that water or any other liquid d/slonce afar? wafer //7.97.0 gloss al eoch end ,i will always seek its own level. In this case we at once perceive that the water level in

Bar/ fo hare I raves °, 1 the two gage glasses will be the true level, '' p2gs o/each end and if we then measure from these points B- indicated on the gage glasses to the surface RAW" hase hlledwilhnok,- of the shafting and keep changing the po- -B- sition of the shafting until these two dis- ias, bolt tances, D and E, are equal, then we know that the shaft is perfectly level. Ifolor bald by log Where several shaft hangers have to be Lb* b evaden beam e rn ÍI g 1. J/w2Van0n e put in place before the shafting is avail- sbrew fg.4 LI , , d -c- able, the hangers are readily lined tip and CG7nnslioe floor secured to the ceiling or side wall, which- tt Cenler ëiï iniermed/ale hangers sinng n/cd /mmcenreil.iv ever the case may be, by means of a center f/9 cord or string, as shown at Fig. 2-C. If Small and Medium Size Dynamos and Motors more than two hangers are to be mounted Are Here Illustrated, Mounted on Both Ceil- Several Schemes Followed In Alining Shaft- ing and Floor. Motors, Even Small Ones, ng. The Stunt Employing by this method, then the two extreme end Should Not Be Held to the Ceiling Beams by Filled the Rubber Hose With Water and Fitted With a Gage ones should be alined and put into place Lag Bolts Alone for a First Class Job, as Glass on Either End Proves Very Successful first. Intermediate hangers can then be Belting Strains and Useful. Are Liable to Putt( (t From readily lined up by means of the center Its Moorings. April, 1920 ELECTRICAL EXPERIMENTER 1279

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

FIRST PRIZE, $3.00 SECOND PRIZE, $2.00 THIRD PRIZE, $1.00

A "TESTED" ELECTRIC FURNACE. MAKING A PERMANENT MAGNE? A CONVENIENT HORN DEVICE METER. FOR AUTOMOBILES. I am a reader of your magazine and a wrist -watch case for about in some of the ex- Purchase 1:ave been interested I have experimented quite a bit on mak- 50 cents and cut out a piece of tin large reriments publisht in it, and am therefore ing various kinds of meters and have found enough to admit a pushbutton, but leave taking the liberty of sending you the dia - great satisfaction in the ammeter here de- large enough to fit the which I the outside rim grams of an electric arc fur. -..ce scribed. Procure a horseshoe type per- watch case snugly. Procure a flexible lamp manent steel magnet, about the size of a cord of sufficient length to permit the ; fine magnet Hoo/in Cube/ Carbon Koo/in Muffe/ telephone magnet a cork, some wire, tin, cardboard and pins, etc. Cut the heads off the pins and insert one in each Tin end of the cork, but be careful that they `äisc`\ do not touch -and wind the wire around the cork, as in illustration, and connect each end of the fine magnet wire to the two f/ectric Arc furnace pins so the pins act as bearings and the Pushbutton ruled resetoncewire fire/inmsub cork as an armature. Mount the armature between two pieces of brass strip to act as bearings and place the armature between Next ..:r.i the poles of the horseshoe magnet. r; ' ; 'q'i. .r,s bend a piece of copper or aluminum wire lyrist watch __ Ta auto horn.. and insert one end into the cork. Mount ho/der circuit the meter on a planed wood base and fix tE a cardboard dial under the wire. Calibrate Resistonce Mount Your Auto Horn Button on a Wrist eE it by means of a standard ammeter and Watch Band and See How Convenient It batteries. Proves. An Electric Furnace That Works! A Rheo Contributed by LEE HOLMES. outside stat Is Used In Series With It. driver to hold one end with his arm the car, as when turning a corner. Now have used in my laboratory for some time connect the wires to the button and with good success. to the electric horn circuit. Our I believe the diagram to be self explana- circuit being complete, let us pass on tory of the method of construction, and to the uses of the pushbutton. You may to your index and second can he made from odds and ends to be Woúurlllllllll.4.101E4- ÿaioióui'=. strap the button found in any shop. I have used the above finger, so that the button may be in place furnace to fuse brass, copper, silver, gold for the fingers to be prest against the wheel and platinum very satisfactorily as a high without removing the hand. Now again, to degree of heat can be obtained. blow the horn while turning a corner. Sim- I also give a diagram of the resistance ply extend the hand and press the button used in connection with the furnace. I with the thumb, and continue to steer the used about thirty feet of No. 24 iron wire car with the other. By this arrangement wound into a 3/16 -inch coil which I then you may blow the horn, signal to turn the wound around a flinch porcelain tube. corner by extending the arm, and guide the This was then suspended in a piece of car -all at the same time. If the driver long and full should not wish to use the button all the brass pipe 6 inches poured Dent Lt^ará79 noted that Ti?,. pinq7in/ fids wir, he may wind the wire around the of plaster of Paris. It must be <,F r time, before this can be used it must be placed i . z steering rod and strap the 'button anywhere pessimists may over a very slow fire and thoroly dried r.a..uo on the steering wheel. But rs.1 I main- out ; else it would either burn out the coil 4.lt6,ÿ1 argue -"They will be easily stolen." or explode, due to the moisture being driven tain that you can place a separable connector off too rapidly. I used this outfit on the , costing 15 cents in the circuit, so that the regular 110 -volt circuit. .0"6 Ar\.ma/ure apparatus may be disconnected and placed moun/al cork 3hnwin9 I find this a Contributed by DR. A. T. FRIEDLINE. toinec/ions under the seat or elsewhere. decided improvement over the present UNIQUE RUBBER FEET FOR method, and think it will be worth a trial by all motorists. APPARATUS. The Simplest Permanent Magnet-Moving I had my wireless apparatus on a high Coll Meter. Nifty for Experimental Work. Contributed by LYLE CASHION. polished table and as I did not wish to the apparatus bridge will easily ascertain the mar the table by fastening A SHORT -CIRCUIT EXPERIMENT. Wheatstone to it, besides being bothered by having the reason, however. It is a well -known fact instruments slide out of place and scratch- Practically everybody knows that if a that electricity will pass thru the conductor top, I cut up some rubber bands battery connected to a bulb is short - of least resistance. ing the out. But look 1 glued them around circuited, the bulb will go (about /" x ") and is Contributed by PHILIP A. WALL. edge of the base, 8" or 10" apart. at Fig. 1. The short -circuiting element the switch M. MAUS. an ordinary battery carbon. Close Contributed by HERBERT A and the bulbs light brightly. Close switch B, and no change in bulb. Why shouldn't l "T-Emai B~-1 it dim? Oh, you think, you only "shorted" one battery. But look at Fig. 2. Here after if A is closed and then B, the bell still continues to ring, despite the fact that all the i El S1á rubber you say, current is short -circuited. Oh, fig.l fig. 2 fig 3 foot current does not pass thru carbon. But 3 and the will ring, of Any connect as in Fig. bell Conundrum: When Is a "Short -Circuit" Not Rubber Feet I The owner of a a Short -Circuit? Electrical Ite Insulation indicating that it will. ` 1280 ELECTRICAL EXPERIMENTER April, 1920

EDITED BY S. GERNSBACK INTERESTING CHEMICAL careful observation you will see the lead the sulfite. A rapid evolution of sulfur EXPERIMENTS. tree grow. dioxid gas will at once begin, and in passing 1. Heat a little sulfur with concentrated 6. Alcohol from sugar. Dissolve 30 thru the U -tube the gas will be condensed nitric acid until it has disappeared. Ob- grams of table sugar (granulated) in 400 to a clear colorless liquid. serve the red fumes. Insert a burning c.c. of water. Pour this into a flask pro- Freezing Action of the Gas-Pour a lit- match into them and note that they support vided with a stopper and delivery tube. tle of the liquid gas into 10 cc. of water combustion. When the reaction is over, Add / cake of yeast and set aside in a in a small beaker. The mixture, upon warm place. It would be well to have the stirring, will immediately crystallize to a delivery tube dipt into lime water, so as solid mass. to show that carbon dioxid is given off. Place a little water on a block of wood Allow this to stand for a few days. You and upon it set a small beaker containing can then distill off the dilute alcohol. This a little of the liquid gas. The rapid evap- is done by distilling about half of the oration of the liquid will produce intense liquid and. discarding the remainder. It cold and freeze the beaker to the block. may be necessary to distill off half again Contributed by FLOYD L. DARROW. before the alcohol is strong enough to burn. A su/pIor dioxide generator wdh dropping 4'3 7. Boil 10 grams of powdered nutgals containing soip/wric cod in 80 c.c. of water. B. Mash bottle calla /ng emm hzvkcesu/urre Filter after standing. oriel There is now tannin in the solution. Add C job ernlo// /ng U- /alb. pocArdino freezing to this a solution of iron sulfate. Some mix /uro of sod onece inks are made in this manner. Ni/i Gas Pigi 8. Place a small piece of phosforous in a porcelain dish (free from water), and the same amount of iodine. The reaction proceeds by itself with the production of much light and heat. 9. Place a little powdered antimony into a jar of chlorin. It immediately catches fire and gives off a shower of sparks. Heat a piece of thin copper 'foil and plunge it into a jar of chlorin. Observe that it .4 C catches fire immediately, forming copper chlorid. Paint a piece of paper with tur- pentine and hold Apparatus Set Up for Experiment In Lique- it in a flame until it be- fying a Gas. Red //lmUS solution gins to light. Quickly plunge it into a jar in beo/rer of chlorin. There will be a flash and great TO fij.3 fig 2 clouds of carbon are produced. Flowers, GIVE PLASTER FIGURES AP- calico, etc., may be bleached by moistening PEARANCE OF MARBLE. and placing Some Very interesting Experiments In Chem- in a jar of chlorin. Put one ounce of grated pure curd -soap istry are Here Illustrated and Described. 10. Make an intimate mixture of equal into four pounds of clear water. Dissolve parts of potassium chlorate and sugar. in a well -glazed earthen vessel. Then add allow the tube and its contents to cool, then Set this in a pile and add a drop of sul- one ounce of white bees -wax cut into add barium chlorid solution and a white furic acid (concentrated). The mass thin slices. As soon as the whole is in- precipitate will be formed. This shows the catches fire at once and flares up. corporated it is ready for use. Having presence of sulfuric acid. The sulfur has 11. A very striking experiment to illus- well dried the plaster figure before the been oxidized by the nitric acid to sulfuric trate the solubility of ammonia gas is to fire, suspend it by a piece of twine, and acid. fill a flask completely with the gas and in- dip it once into the above varnish. Upon 2. Burn a little sulfur in a bottle of sert a stopper provided with a straight taking it out the moisture will appear to oxygen and note the phenomenon. Do the piece of tubing. (See Fig. 3). To this have been absorbed. In about two minutes same with phosforous. This time if the is added a piece of rubber tubing over stir the solution and give the figure an- room is dark, the reaction will be more which a clamp is placed. To this is at- other dip. Two dips are usually sufficient. brilliant. Burn some charcoal also in tached another straight piece of glass Allow the figure, carefully covered to oxygen and note the scintillation. Slip a tubing which dips into the bottom of a protect it from all dust, to stand for a small piece of cotton into melted sulfur, beaker of red litmus. When the clamp is week, then with a soft muslin rag, or then attach it to a piece of picture wire. opened, the water . rises and the color cotton wool, rub the figure gently, when a Ignite this and lower changes to blue. This will take place most brilliant gloss will be produced. into a bottle of oxy- sooner gen. Note how readily the wire burns and if water is put into the upper piece Contributed by the globule of red hot iron that forms on of tubing. (Fig. 3). WALTER CHAS. MICHEL. the end. Contributed by 3. Generate hydrogen and allow it to es- EDWARD MARENZANA. METHOD OF TESTING WOOLEN cape from under water. Hold a lighted AND COTTON THREADS. splint over the escaping bubbles. (Fig. 1). LIQUEFYING A GAS. Take a As each one escapes it is ignited and ex- The few threads of the material to plodes. actual liquefying of a gas is an be tested and place in a test tube with This sounds like a miniature bat- experiment of great interest, tle. Another way is to blow hydrogen and in the enough nitric acid to cover them. Bring case of sulfur dioxid easy to carry out. just to the boiling point bubbles and as they rise, set fire to each. The apparatus over a flame and (Fig. 2). is set up as shown in the allow to cool. Pour a small quantity of diagram. A is an Erlenmeyer flask carry- ammonium hydroxide in the tube and note 4. Dissolve some yellow phosforous in ing a dropping funnel carbon disulfid and containing in the change. If the liquid is not changed in and paint a sheet of paper the bottom a layer of sodium sulfite with this solution. In a darkened room pow- color the material is cotton, but if the der. The funnel contains a solution of liquid assumes an amber color the material the phosforous will glow after the carbon sulfuric acid made by pouring disulfid has evaporated. Do not leave the the concen- is woolen. In either case dense white trated acid very slowly into an equal vol- fumes of ammonium nitrate will be solution or brush around. The bottle ume of water and allowing should always be tightly corked. to cool. B is evolved from the tube. a gas -washing bottle containing concen- Wool contains much nitrogenious matter 5. Dissolve 15 -20 grams of lead acetate trated sulfuric acid. C is a battery (sugar of lead) in 500 c.c. of water and jar while cotton contains none. This accounts containing a U -tube packed in a freezing for the change. The above is a sure test. place in a wide mouth bottle. Suspend in mixture of salt and this ice. I have used it repeatedly. liquid a piece of sheet zinc by a string. After the set -up has been made allow Allow it to stand for a day or so. the Contributed by By acid from the funnel to drop slowly upon JOHN ELIOT CHRYSTAL. April, 1920 ELECTRICAL EXPERIMENTER 1281

RADIO DEPARTMENT

Some Lon DIl temce mclIlo Te,eph®ne Teata ROt3ERT F. GOWEN*

S 1 RIES of radio telephone tests andd Upon installation, no difficulty was ex- tories at High Bridge, but when later, ex- experiments by the writer per- perienced in making the transmitter operate periments were made to cause the set to formed during the months of De- successfully on 750 meters for tests and oscillate at 200 meters in order to work with cember and January have produced demonstrations with the deForest labora- the amateurs, it was found that the con- some results which may be interest- stants of the circuit were such as to make ing to the readers of the ELECTRICAL it decidedly unstable at this high frequency. EXPERIMENTER. The results are interest- After a good deal of experimentation and ing, not only because of the records made, adjustment, however, fairly good results but of the peculiar conditions under which were obtained at a wave-length of 330 the experiments were performed. meters which, it will be noted, was below The transmitting equipment consisted of the fundamental of the aerial. a standard one kilowatt deForest Oscillion Using this wave -length during December panel transmitter which is designed to work the writer attempted to communicate with on large ship type aerials on wave -lengths amateurs in the vicinity of New York and between 500 and 1000 meters. This trans- found great difficulty in making the tele- mitter uses two / kilowatt power tubes graph signals heard because of the ex- for the generation of the high frequency tremely sharp tuning of the emitted wave currents. The plate current of these tubes and also because very few amateurs listen is supplied from a motor -generator set on wave -lengths over 250 meters. which delivers a voltage of 1500. The On the 330 meter wave -length the trans- tubes are of a new type made of Pyrex mitter would put but 2.4 amperes into the glass and the plates are of Tungsten so aerial with an imput of 300 watts, tho a that external cooling is not required. The maximum of 2.6 amperes could be obtained tuning is done by means of a variable sec- with an imput of approximately / kilo- tional series condenser and by varying con- watt. Owing to the unstable conditions tact clips on a helix in the rear of the caused by the circuit constants the oscil- panel. The circuit employed was of the lator had very poor efficiency and about standard deForest single tuned type with January 1 the writer was surprised to have capacity coupling between the grid and plate a report that the signals were being heard circuits. at Utica about 175 miles away. Mr. Benas A special new type of modulating cir- at Utica reported by radio telegraph and cuit developed by Mr. C. V. Logwood was by letter that the music sent out at the installed, the novelty being in that both the Ossining station could be heard 100 feet grid and plate circuits of both tubes are away from his telephone receivers when modulated by the voice currents at the using a two step amplifier, so that in two same time. Continuous wave telegraphy is Photo Above Shows the Author, Mr. Robert instances, his friends there had used it as a by making and breaking the F. Gowen, the Radio Engineer Who Talked dance orchestra. accomplished 1,500 Niles on Less Than 300 Watts, or About grid leak circuit and a modulated wave was One -Fifth of a Watt per Mile. He Is Shown It was apparent from this report that, added by substituting with a switch, a buz- Holding a New De Forest 1 K.W. Transmit- altho it was difficult to get amateurs to key in place of the microphone. ting Bulb or " Oscillion." Photo Below Shows and the calls zer and Amateur Radio Station of Mr. Trump at To- listen answer on 330 meters, The transmitter was installed at the home peka, Kansas. He Received the 1,500 Mlle when the signals were once tuned in, they of the writer in Ossining, N. Y., and con- Radiophone Speech Sent Out by Mr. Gowen were very loud. This incentive prompted nected to a compara- at Ossining, New York the idea of working tively small aerial, later at night when four wires 170 ft. in the amateur inter- length with a spac- ference was less, and ing of 30 inches and shortly thereafter with an average Radio Station 8ER height of 55 feet. A answered a call and 60 -foot lead -in was reported that they tapped off the end were at St. Mary's, nearest the station Ohio, more than 600 and brought to the miles away. transmitter through Continued efforts a hole in a window in adjustment of the pane. This aerial circuit and methods has a capacitance of of calling them approximately .0007 brought in reports mirco -farad and a from many stations fundamental wave- thruout Ohio, and length of about 355 Indiana. Reports of meters. successful reception The ground sys- of the speech were tem consisted of 84 received also from square feet of cop- Wakefield, Massa- per sheet buried be- chusetts, ' Gaffney, neath the founda- South Carolina, Na- tions of the operat- panee, Ontario, about ing room about 8 this time, increasing feet below the trans- the distance to about mitting apparatus. 750 miles. Subse- There were also ad- quently a letter was ditional grounds to received from the the water pipes, gas operator on a yacht pipes, heating ap- Photo from Underwood & Underwood 300 miles Robert K. Trump, 21, a Former Sailor Living In Topeka, Kansas, Overheard Phonograph south of paratus, etc., of the Music and Conversation Between Robert F. Gowen, Engineer of the DeForest Radio Tele- Jacksonville, Florida, house. phone and Telegraph Co. and R. H. G. Matthews of Chicago (Cont. on page 1326) Engineer deForest Radio Tel. and Tel Co. J 28 ELECTRICAL EXPERIMENTER April, 19220 aaDIlrec MuoIlc 400 MfiRen Toy Radio Cua-renI" `I! ican(,5:mIl4Qer If you haven't your favorite jazz melody in all experimental work and the last rating A new radio transmitter has been de- and if there isn't one within 400 or 500 was given 992 per cent. The photo shows velopt by L. M. Cockaday, of New York, miles, don't let that worry you. Just send L. W. Elias and the machine. which operates on a direct current source a radio to the nearest wireless station, and The wireless telephone is not so much have them put the desired record on the of a novelty any more, altho of course, instrument, put your receiver in operation, the apparatus is not to be had for a mere and you have it. song. However, our radio experimenters, Everyone knows even the youngest, are rapidly becoming the wireless has experts in the development and construc- proven a success- tion of simple apparatus, whereby it is pos- ful invention, but sible to transmit articulately, the spoken very few know all word. In transmitting music or vocal rec- the uses it may be ords from a phonograph by means of the wireless telephone, there are several different ways in which

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIP. By Means of the Phonograph and Wire- less Telephone Appa- ratus Here Shown, Dance Music Was Re- cently Transmitted 400 Miles by Radio to Some of Uncle Sam's Convalescent Soldiers. Photo (e) by U. & U.

I11IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII1111111111I111IIIIIIIIIII11111111 New Direct Current Wireless Transmitter Giving a Clear Note Equivalent to a 500- Cycle Synchronous Spark Set. Its Secret Lies in the Use of a Rotary Synchronous Spark Gap and Inter- rupter In Place of a Fixed or Stationary Spark Gap and Ordi- nary Interrupter. dIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII the air waves set up in the phonograph sound chamber may be communicated or super- imposed upon, put to. The other day L. W. Elias, officer in the Wireless t el e phone transmitting of power, the system being such that it charge of the Chicago U. S. Radio Station, apparatus, and eventually to the antenna eliminates the motor -generator now used was successful in sending a complete mu- from which this is liberated into space, in in connection with spark set transmitters. sical program to Fort Sheridan's convales- the form of electro- magnetic waves in the In the primary circuit a rotary inter- cent soldiers. When he had finished, to his ether. In some cases, the microphone of rupter is used in series with the primary surprise the operator in Detroit compli- the modulating circuit of the wireless tele- coil of a step -up transformer, in combina- mented him on his progress and advised phone outfit is placed in proximity to, or tion with a synchronous rotary spark -gap Mr. Elias that he had connected his instru- secured tightly to, the phonograph sound - in the secondary circuit, as shown in the ment to a transmitter and that over 100 box proper: In other instances, one or diagram. people had heard his music. He was also more microphones of the modulating cir- The relative positions of these two wheels told that everyone in Camp Grant had cuit have been placed in the amplifying are so adjusted that as the interrupter heard the same program. The apparatus sound chamber of the phonograph, and this closes the primary circuit, the condenser necessary to transmit music in this manner has been found to give very good results. in the secondary circuit can discharge only is a phonograph with records, a transmitter, A microphone placed inside the doors at its maximum capacity ; that is to say, and receiver combined with a power plant or grill of the phonograph has many good the spark -gap comes into sparking position connected with batteries. The transmitter points about it. This is so for one reason just as the interrupter opens the primary consists of one oscillating and one modulat- that the sounds created by the diafram of circuit, thereby obtaining its highest ef- ing tube. Any amateur receiving appara- the phonographic sound -box have not their ficiency. tus within a radius of 400 miles can inter- full vibrating timbre and sonority when The interrupter successively opens and cept the sound waves as they are sent on they first proceed along the tone chamber, closes the power circuit a sufficient number undampt waves of 700 meters. The Chi- but receive their full sonority only after they of times to obtain a clear 500 cycle tone cago Government Radio Station ranks first have entered the larger amplifying chamber. which is always steady.

Audì1onn AllIerrnaIIl>ryd CurTfen4 Aga.Iln ó As several readers have inquired about both separately and together, and got rid illustration ('ultraaudion' hook -up, the sec- using audions on A.C., and how to get rid of all noise. A friend of mine has also ondary being connected to grid and plate, of the hum, etc., we referred these to had success with it on the filament alone - not grid and filament). 3. The tuning ad- Mr. Elliot A. White, author of the article 'as silent as a church,' he told me. I be- justments of inductance and capacities must "Operate Your Audion on A.C.," which lieve the Navy used toy transformers for be properly made, this being delicate, as I appeared in the July issue. Here are some filament -lighting at 'Great Lakes' during said. 4. Any foreign sources of interfer- valuable pointers from Mr. White: the war, and I have also heard of its use ence from A.C. must be eliminated. "In reply to your queries, I understand by the Navy and by the Federal Telegraph "If your complaining readers are cor- your first paragraph to mean that the Company on the 'Coast,' so you see it can rect as to 1 and 2, then their trouble is queries concern the use of alternating cur- be done all right. I suspect the trouble in with either 3 or 4. Concerning these, I rent for the filament only. the cases you mention is probably due to would refer them again to the article, par- "My experience has been that it is easier the Experimenters themselves, as I sug- ticularly to the second and third paragraphs to use A.C. on the plate than on the fila- gested in the article, for I by no means from the end. It is, of course, also possi- ment, because in the former case the large claim that the device is 'fool- proof.' ble (I know of one such case) that the condenser across the leads from the recti- "However, you might call their attention Experimenters are getting cross -talk from fier keeps the 60 -cycle hum out of the cir- to several important points, all of which near -by power lines to antenna outside the cuit. It is more difficult to use the A.C. were treated in the paper : 1. The connec- house, or from house wiring to the set for the filament only, as it is sometimes tion to the balancing resistance across the inside. either by capacity effect or by direct hard to get rid of the hum. However, I filament must be properly adjusted. 2. induction. I should think you would find have personally, as I said in the article, Connections from the tuned circuit to the it difficult to handle these problems with- used the A.C. for both plate and filament, detector must be made exactly as in the out being on the ground." April, 1920 ELECTRICAL EXPERIMENTER 1283

France. Photo at Left Shows the Famous New High- Powered Radio Station at Croix d'Hins, Which Is Located Just Outside of Bordeaux, Radio Receiver Which Automatically Has a Total Power Rating of Some 1,000 Odd Kilowatts. Photo at Right Shows Remarkable New It Delays in Answering Distress Rings a Bell Signal on Ship, When Another Vessel is Sending Out an "S.O.S." Cali for Help. This Will Avoid Calls at Sea. Latet Radio News

THE accompanying photograph at the and spark sets with a total rating of some "listening in." It has sometimes been the left shows the gigantic steel towers 1,000 odd kilowatts. case that such signals have not been heard Lafayette radio even by ships quite close to the vessel of the powerful fact station of Croix d'Hins, located 15 AUTOMATIC S.O.S. BELL SIGNAL FOR SHIPS. calling for assistance, owing to the miles outside of Bordeaux, France. that the operator may have been off duty This station, one of the most powerful if The photograph presented herewith at at the time, or for some other reason. not the most powerful in the world, was the right illustrates a remarkable new We have long advocated such an appa- started in 1918 by the U. S. Navy to enable radio invention which is said to pick up ratus as this for receiving and interpreting to be carried on in a and translate "S.O.S." calls from ship sta- "S.O.S." calls at sea, for many reasons. It radio communication a positive manner at all times with the Amer- tions and to cause a bell to start ringing is a simple matter now -a-days to rig up the Atlantic in the station receiving the call. in other positive working apparatus which, by means ican war vessels traversing will Ocean and other waters. words, when a ship in distress sounds the of sensitive relays ani amplifiers, since been turned over to S.O.S. call (the International radio signal serve to close a local circuit containing a This plant has a call the French government by special arrange- of distress, to which ships of all nations sufficiently strong battery to actuate ment. There are eight giant masts, each pay strict attention under the present regu- bell circuit. Earth," lations, in order to try and speed toward The main purpose that the bell signal rising 825 feet above "Mother attention which serve to support the antenna con- the disabled ship and render succor, if in this case serves is to call the possible), the radio signals, flashed out of the radio operator in charge, and pos- ductors. the the armistice was signed the U. from the vessel in distress is picked up on sibly the ship's commanding officer, to When signal is being received. S. Navy Radio Department discontinued the antenna of other ships within a radius fact that a distress plant was of several hundred miles and if fitted with When this has been done, the operator of work on the stations, but the to receive the completed by the Pittsburg -Des Moines this apparatus the message of distress course "listens in" in order will give an audible signal on the belt at further details of the distrest ship's loca- Company for the French government. both This plant will have various types of once, without taking a chance of whether tion, which is given out by wireless radio transmitting equipment, including arc it will be picked up by a radio operator as to latitude and longitude. New Amateur WIl1F'elle.a TEann-11.IlttIlng Set Z' General amateur transformer f rom all undue current wireless telegraph f stations are re- surges. The trans- stricted to a transformers are design- wavelength ed to be connected mission directly to a source of 200 meters, and cur- a Chicago concern of alternating has developed and rent, no choke coils placed on the mar- being necessary. ket wireless tele- Capacities of 1, Y, a and / k.v.a. graph transmitting (kilo-volt-amperes) set designed to give the the best results on are made, but - k.v.a. transfor- this short wave- / have length. This set in- mer does not cludes a transfor- the magnetic shunt mer, condenser and control. The center oscillation transfor- device in the illus- mer and a rotary tration is the con- spark gap, all of denser. This is of which are shown in the oil - immersed the accompanying type. There are ten illustration. terminals arranged The transformer so that the capacity is of the closed - can be varied from micro - . core, air -cooled type 0018 to .009 with a double mag- farad in single steps netic circuit. A fea- of .0009 micro - ture of the con- farad each. One struction is its mag- k.v.a. = 1000 watts 100 netic shunt control, Radio Transmitter Desi,ned for 200 Meters Wave Length. Built In at per cent Complete Amateur power factor. which protects the Sizes from 'í to 1 K.V.A. .1284 ELECTRICAL EXPERIMENTER April. 1920 0 e._ ve (0)n.zoE. By EVERETT LEO DEETER.

HUNT up all your old telegraph it's too small inside, and if you were to get the small vessel goes under and if left coils, your extra Audions (you the "flu" your temperature might go a mile alone it always takes who have fat pocketbooks), a little time for it to and high and it would be impossible to get it come to the top, being partly filled with prepare to settle down to busi- down again- anyhow you could use it to ness, water. Of course, if the arm is constantly for here's a new stunt to hang your aerial on. being pulled down float try, and you can become the is also pulled a great "profes- Here we go-get your electrical dic- under. Now as long as the float is not en- tionary and turn to diagrams-make sure you know what sign represents a relay, coherer, battery, etc., as you hardly ever see this one, and then after six or seven hours of real study we can almost realize the following facts: If you focus your luminaries on diagram No. 1 and was just to imagine that some poor jay wireless amateur was to send out ippongua a right smart wireless wave, which was by mdsp,áj decrement and other complicated mathematics of the same metric wavelength as that of our elaborate de- cohering outfit, why then Çpn our clumsy antenna would probably make a successful attempt and "down 1770/1 ironskvmer the thing." Now if the wave gets thru the ton be used in poco coherer to the ground of the above bet it causes the filings to get close enough together to lessen their = fig resistance, and then things begin to hap- Amplifying Circuit Provided With Two Au- dions Connected to Sensitive Polarized Diagram Showing Connection of Coherer Relay, Which in Turn Actuates the Special and Decoherer With Polarized Relay, and Selective Relay Here Described. Also Special Selective Relay Fitted With Dash -Pot. tirely up the main circuit for the display sor," apparatus is open and therefore they do not or a "wizard," by amazing people in operate. But your own home town by the act of control- when the arm is up then the ling numerous circuit and the apparatus circuits operate distant apparatus, simply by on the point the pushing a button on your radio-sending switch is left on. outfit. Now for the conclusive diagram, No. 3. By following This shows the back of the control board, the construction details and mainly the given herewith a wireless control board circular switch. Now supposing we had No. 1 of which works very well can be easily con- the switch connected to an electric train or street car, No. 3 structed, and by its use the amateur can to operate any certain apparatus a little windmill, No. 4 to an electric connected to light, No. 5 to an the board without first operating others, electric cannon, etc. We thus making want to cause No. 1, the train, to operate. it a true selective control. We push our transmitting Now if you are done with that message button four times we'll go to work and toot-toot she goes. Now we are asked -yes, tell your neighbor to to shoot our cannon, No. come over, too, for after he sees your's 5, and all we have OWOi/ of water to do is to push the button four more he'll want one, too. First we will see for times ourselves how f0ö/ ay' MIR and bang! For No. 10 we would now push the thing works. fiy S:! e five times, etc. For simplicity we will consider the use of r ouw,.. Two and ten on the a coherer poor °á111m switch are stop blanks, -the nut may be forced to while 16 can use one in his actual model be a place where they all oper- -and if he ate, making the segment of eleven narrow spent all his money for auto cable to try out the DO-Oa strips, not touching one another and con- "underground trick" but, anyhow, nected to all other segments a coherer works quite well. of the switch. But don't let Retire for the night now, for you'll need anyone catch you when you file up a nickel all kinds of strength and dime for filings. And and ability, as well as don't break up Illustration of Details to Be Followed In (Continued on page 1334) the family thermometer for a tube, because Constructing the Selective Radio Control Relay Here Described.

pen. When the platinum (if you're rich) , points close, of course the juice goes thru , c and makes the magnet pull down the arm which operates the sprocket wheel, in turn A `' operating the commutator or the switch G 9=. N ' j controlling the display apparatus. If you f think you now understand s ` all you've been "M over, proceed to diagram No. 4 also. If p you don't proceed anyway -it'll do your think tank good. When the arm is down u `; -- it makes contact to J, and this gives a little 0 stingy juice to the bell, what there is of it, 5 which hits the glass tube of the coherer and . e N knocks the : lings apart, ready for another N . "jazz." But this is not all the clumsy ..Iá brass arm did -the string seen between C and M .t r ! IIIIIIIIIIIIIIIIIilllllllllllllllllllll pulls the arm B, and out at the end where " 1 the f I plunger R is connected at O there is qil Y quite an emotion as the arm drops thru a v IIIÍÍÌIIIIIIIIIIIIIIIIIIIIIIIIIIIIÍÍIIÌ I .. I t long arc, which may be varied by sliding , 7 IIMI r, t, the arm at N. Qaby f The plunger R is connected to a small ® ® ® :'® 0 e 0® 0 0 e air -tight vessel partly filled with water, and this floats upon the water enclosed in the P 4 larger tin can P (see Fig. 5 -A). Now when Rear View of Selective Relay Switch -board- the arm come,. down the "ship sinks," and Front View of Selective Relay Switch- board. April, 1920 ELECTRICAL EXPERIMENTER 1285 r Ve sus IPTe® ar Apalawat By 6cGPAREISfla C. E. Radio, U. S. N.

THERE seems to be a marked ten- AS TO APPARATUS. as is a motor -generator. We are mostly dency among radio experimenters of concerned with detectors, however. The the present Now as to the apparatus itself. A new to lay their hands on the form of layer war tubes were designed to combine rug- new developments in radio appa- wound inductance has made its début, in the form of pancake loading gedness, reliable operation in inexperienced ratus, particularly as applied to vari- hands, with a fair degree of sensibility. In ous receiving instruments which have been coils, and is also being embodied in several last forms of loose -couplers. The coils have the named requirement they did not brought out during the World War. From exceed the specifications in the least. It is what I can gather from various publica- given good results, when used as loading inductances and coupler coils, and have the true that such bulbs require no variation of tions and 1 tters from the Amateurs, a plate advantage of taking up much less space voltage and will operate over a mod- great demand has arisen for the most moderate range of filament current fairly well, em of apparatus. This than the old type of cylindrical tube wind- demand reflects a ings. is but the Navy VT's all require a plate volt - spirit of progressiveness in the Amateur, It also easily possible to incorpo- age of from rate these coils into panels, which are very seventy to one hundred and it is true, but there is a limit to all things, fifty volts. I have used probably two hun- and the adoption of all the new and fancy popular, and make a neat job of it. The layer wound coil wound with an offset dred different Navy tubes at times, and have frills which are being described from time -IF yet to find one which equals the little old to time will lead to a limit where the dis- winding (honeycomb coils) is a distinct step "tubulars" for forward, and full credit should be given it. sensitiveness. A new bulb tressing facts are all too plain -that the has recently come into prominence, which I little old stuff that we used to "gather in" Experimenters, in buying, however, should have had demand this offset winding which makes no opportunity of trying out as the signals with, was far superior to sev- yet, but which seems to be "the goods," enty -five per cent of the war apparatus. the coils what they are-extremely neat, as it is becoming compact and efficient little units. popular with a great num- I have had considerable experience with ber of Amateurs. It requires but a low A word now about capacity coupled tun- plate voltage not the majority of apparatus which was ers. These were tried on various vessels, required to be varied brought out during the period of hostilities, and seems to promise much. Until I have and in shore stations, but were found to be had the opportunity having used practically all the latest de- impractical for spark reception, due to their of trying it out, how- velopments under typical operating condi- ever, I shall stick to the old "tubulars" for extreme sharpness of tuning, which made all around tions, and for the benefit of those whose them poor "stand -bys." In certain cases satisfactory work. I have tried longings for "Navy VT's," "loop antenna," the new bulbs as amplifiers, by doubling the the tone of the incoming signal was also plate voltage etc., are getting the better of common sense, distorted by them. For these reasons their -sometimes even tripling it- let me outline a few of the results I have and have found them to be excellent for that purpose, better in fact than the tubular obtained with new and marvelously effi- 1111111111111111111111111111111111111,1111111111111111111111111111tttt1111111111111111111111111111111111111111111111 cient ( ?) war radio apparatus. bulbs, which are poor amplifier tubes. All this crabbing would naturally lead up AERIALS. n AprIlfl¡¡yy to the question of what I would consider a good Amateur Set for receiving. My idea Let 661SliCSt1}1®c II77 us start at the top, this being the Amateur is, after testing, planning, designing and aerial, of course. Before 1917 we Amateurs trying all manner of sets for the past two used the good old inverted "L" or "T" years, to havé a short wave set, with a type, flat -top antenna of the four- or six - News" range of one hundred and fifty to six hun- wire size, elevated from thirty to fifty feet, dred and fifty meters, to include both Ama- and we got GOOD results. A certain teur and Commercial marine waves, and Portland (Ore.) Amateur, regularly com- Wireless in Modern Aircraft. get good efficiency on each. The circuits municated with a station in Los Angeles By A. J. Hall should by all means be regenerative, using and with a Reno (Nev.) station also. one of the old tubular bulbs. If it is de- Chicago Amateurs were heard up to one The Priess Loop Set, Part IV. By W. J. Henry sired to amplify these sets, I would sug- thousand miles, and the east coast stations gest a two -step amplifier using the new were easily heard in the Middle West and New Facts About the Nauen Amateur tubes. The transformers should South. All this with one K.W. or less and Station. perhaps be purchased until more data is on two hundred meters! In my tests, I By Dr. A. Gradenwitz published regarding their construction than used an antenna of the typical flat -top "T" Aladdin's Lamp. is now available. The telephones should type, three hundred feet long and eighty By C. S. Wolfe preferably be of the mica diafram type, or feet high, four wires, and with a two -kilo- if the price is prohibitive a good two or watt, five hundred -cycle set, was able to A Resonant Transmitter. By W. S. Lemmon, E.E. three thousand ohm, double headset. cover twenty -two hundred (2,200) miles Besides the above set, all well equipt Ama- at night on six hundred meters, at sea. Easily Constructed Radio Mast. teur Stations should have a long wave set, Substituting a loop antenna of four hun- By E. L. Deeter capable of receiving the undampt wave sta- dred ninety (490) meters natural period, tions. While personally I do not care for I obtained a radiation of seventeen am- the sustained wave system, it seems to be peres, but my signals were only heard at a the coming thing, so we must all keep up distance of two hundred seventy miles. with progress. An efficient arc receiver The vessel with which I carried out these adoption as spark receivers never became very popular, but in long wave undampt would comprise a long wave coupler, ca- tests used an Amateur tubular audion bulb, pable of receiving waves up to ten thou- with no amplification ; with his Navy VT wave receivers they seem well adapted, for their sharpness is an advantage there, and sand meters at least, two or three variables, he could hear me very faintly at two hun- mica diafram phones, and a good oscillating dred forty miles. I made several similar it also seems that the more variables that can be crowded into an arc set the better bulb with a modern oscillating circuit. A tests, elevating the loop, etc., but on no very good undampt wave set can be made occasion was I able to do better. On the it works. Capacity tuners, however, will never become popular in Amateur Stations. from the unit inductances now on the mar- other hand, the loop antenna for receiving ket, layer wound as before described. Sev- is not at all bad. I picked up signals from The heart of the receiving station draws our attention next. I have heard more eral reliable concerns are putting out such Lands End, England (GLD). at seventeen inductances in neat individual cabinets of hundred miles, with one tubular bulb Amateurs whine, sigh and express extrava- gant promises of reimbursement to anyone varying wavelengths, so that the induc- (eleven hundred miles on a Navy VT), tances can be placed next to each other . and merely placing the loop on the bridge. who would get them a Navy VT than desires for all the other new apparatus that and used as primary and secondary coils, The chief objection to the loop antenna for the coupling by changing the dis- reception in Amateur Stations is its marked has appeared. The prevailing opinion seems between the coils. tance to be that for sensitiveness are mar- If a receiver such directive effects. In some cases this would they as this is properly made, very good results be an advantage, in cutting out interfer- velous- unequaled ! Where this idea ever will be had found root is puzzling, with an antenna of one single ences, or receiving signals from but one in the face of the wire, several hundred feet long, which need general direction and its opposite, but very fact that the majority of tubes developed for war purposes not be more than thirty feet high. few Amateurs will care to limit their receiv- were, and are, miserably A good ground connection is vitally im- ing possibilities to but one or two points poor bulbs in comparison with the tubular bulbs we had formerly portant in every case. Solder your ground of the compass. The loop invites experi- used. This applies lead to a water pipe, and make it of heavy mentation, but don't be so all -fired het up to their use as detectors -they make good cable. In addition, ground to everything about adopting it without trial in your pro- amplifier bulbs when used with 150 to 300 within reach -steam pipes, etc. It all helps. posed station. Stick to the flat -top, inverted volts, plate current -but where will the If care is exercised in the construction "L" or "r' types -they aren't going to be modern Amateur, even, get that voltage, and installation of equipment, and instru- back numbers at all. D.C.? Batteries are out of the question, (Continued on page 1330) 1286 ELECTRICAL EXPERIMENTER April, 1920 ITAVe y JAY G. HOBSON THERE are several kinds of razor top to allow for refilling the same, and at blade sharpeners on the market. Few the bottom end would be arranged a small of them have met with considerable CAP measuring cup or valve operated by the success because they really sharpened thumb and forefinger of one hand while as claimed. However, all of the DISPEN SER the other hand held the toothbrush under various designs require the user to turn a the spigot to receive an exact amount of small crank to operate the stropping ele- powder or paste sufficient for one good ment. It consumes enough time preparing cleaning of the teeth. one's face for the trying ordeal without As will be seen a little device of this having to stand around cranking the sharp- kind installed in each bathroom, or Pull- ener until the razor blade is ready to man car, would not only economize in the shave. use of the preparation, but it would always Why not construct an automatic razor be handy and ready for use of each member blade stropper to be fastened on the water of the family. Having it ever before them faucet as illustrated, one that will run when with this kind of a slogan printed thereon, the water is turned on so that your razor "USE ME TWO TIMES A DAY AND blade will be nice and sharp by the time THUMB SCREW I'LL KEEP THE DENTIST AWAY," you are ready to shave. An efficient sharp- VALVE would remind them of the importance of ener of this kind could easily be made as keeping their teeth clean. An attractive shown, with a light metal case, two round device of this description would sell to stroppers connected by small gears and most every home and probably be used operated by a little water wheel enclosed extensively by some large dentifrice manu- in part of the sharpener case. The blade facturer. can be arranged to strop on both of the iIIIIIIÌ(NIIIIfIflNlfl Watching a fat gentleman bending over revolving strops thru an eccentric connec- three times trying to reach his shoes to tion with the blade holder. When you tie a broken or loosened string, while some- wish to shave fasten the sharpener to the TOOTH POWDER DISPENSER what amusing, suggested an idea for a water faucet, place the razor blade in the Instead of Losing About Six Tooth -Paste needed improvement in shoe laces. The holder, turn on the water and by the time Tube Caps Every Month and Doing an In- present kind in universal use is really un- you are ready the blade will be in fine terminable Amount of Cussing About the satisfactory for many reasons. cutting condition to make shaving a pleas- Paste That Went to Waste or Soiled Your Clothes, -Why Not Invent a Neat and Cheap To begin with it is forever coming un- ure. Every user of the modern safety Tooth Powder Dispenser Like This? Zip - tied, wears out quickly, breaks just when razor would appreciate an improvement of Turn the Thumb Valve and -Presto! You we don't want it to, and causes flat feet this kind and gladly discard all other types Get Just the Proper Quota of Tooth Powder on Your Tooth - Brush. because there is practically no give in the for this design. string when we walk, run or jump. Rais- The average person becomes so adjusted ing up on the toes in walking causes the strings to force the arch of the foot down- 'WATER to the present tooth brush and tube of SPIGOT paste or can of powder now in use that no ward instead of allowing it to follow the SMALL thought of an improvement in this line motion forward as is natural when walking STROPS DRIVE barefoot. GEAR seems to appear. However, on second consideration we can easily see that there is great inconvenience and waste WATER in the seemingly efficient dentifrices of WHEEL today. For example, remember the time you made a hurried trip to some distant point via Pullman, throwing necessities into BO your traveling bag as you ran out of the HOLDER door. Recall how you had to stand on your head in the berth trying to find your tooth paste before retiring, and how very LARGE DRNEGEAR evasive it was. Finally you gave up hopes of finding it "W' WATER OUfl.Et and went disgustedly to bed? AUTOMATIC RAZOR STROPPER On other occasions, at home when you were METAL SHOE LACE And Speaking of Shaving, -Why Cannot late for work and forgot to put the cover Someone Give Us a Low - Priced Automatic, back on the tube of paste which was hard Ever Try to Lace Your Shoes In a Hurry? Safety -Razor Blade Sharpener Which Could and useless when you This Includes Ladies and Gentlemen, as Well Be Connected to the Kitchen Spigot. A returned home that as the Little Folks. Here's the Author's Small Cheap Water Motor, Specially De- evening? These experiences are a common Suggestion: Do Away With the Everlasting signed for the Purpose, Would Rotate the kind to most of us. To overcome these String Laces Which Are Forever Losing Strop Wheels In Apple-Pie Order. Mr. Hob- difficulties and add to the pleasures liv- Their Tips, and, Instead (When They Are son Guarantees to Sell One of These to of Manufactured), Get a Dozen or So of These Every User of a Safety Razor In the United ing I thought of what should prove to he Spring Lacers,-and Besides, Your Foot Can States and Foreign Countries, -the Bolshe- a very welcome departure in every bath- Really Have Free Movement In This Expan- vik Regions Not Included! room, every Pullman car, every public wash sible Shoe Top! Not Bad, Eh? room and every place where dentifrices are used. As shown in the illustration So an improvement in shoe laces is in During the influenza epidemic eating in my conception is in the form of a neat metal or order. One that seems practical to me public restaurants and cafés was rather a porcelain bracket could be made of a small, flat, adjustable risky thing to do because public to which is secured a eating round tube or can embracing a removable bar or strip of metal with a stout coil places are not careful in cleaning dishes spring concealed inside. This little bar and cups before using them again. In LIP MOUTH GUARD is cut in the diddle to allow for expansion drinking hot drinks from the common and adjustment to shoe. At either end cup people place the rim of the cup be- of this flat, hollow bar would be a blunt tween their lips and draw the liquid into hook or catch "U" shaped and only large their mouths. This is a very easy way to enough to fit into the eyes of both sides of catch the "flu" or some other contagious the shoe as illustrated. disease, of which there are many. To The small coil spring pulling on both avoid this possible exposure a small cellu- ends of the flat bar would force the shoe loid (or even paper) lip and mouth pro- sides together and hold them as securely tector could be made like that shown. as a shoe string, but, in addition, this im- It should be made to fit the rim of the provement would allow for a free move- cup snugly so that the contents of same First on theiProgram of Things to Invent, - ment of the foot when walking, thereby We Have What Mr. Hobson Suggests for a could not run under and out upon the "Lip and Mouth Protector." Afraid of preventing much of the present day foot user's clothes. A little sanitary invention Catching the "Flu" or Some One of 57 Odd troubles. A practical article of this kind of this kind would undoubtedly meet with Fevers? Carry a Little Lip Protector With should sell rapidly and be adopted by approval by thousands of folks who You and Slip It Over the Edge of the Cup are Where the Nasty Little Germs Are Wont to the large shoe manufacturers. particular about their health and desirous Sleep Until You Drink, and Then, Good (This is the third article by Mr. Hobson. of avoiding any exposure to others' care- Night! Yes, We SHOULD Have Them! The next one will appear in the May lessness. Copyright- 1020 -by Jay G. Hobson. issue.- EnnoR.) Arril, 1920 ELECTRICAL EXPERIMENTER 1287

Theatrical Appliances. Wireless Transmitter. Eliminating Undesired Ship Salvaging. (No. 1,324,680, issued to Langdon (No. 1,315,197, Issued to Earl C. Vibrations. (No. 1,324,336, issued to J. T. McCormick.) Hanson.) (No. 1,319,521, issued to R. A. Rreneman.) This patent relates to a method This patent is the latest for trans- Fessenden and F. H. Leslie.) This is another of those patents of producing illusionary effects mission of energy by means of elec- This patent is for sound produc- which are planned to salvage sunken whereby ships and other objects are and electro- magnetic inducing bodies, such as diaframs, and its wealths and treasures. The patent. trostatic that 1 °sage tion. It employs audio frequency object is to suppress any desired ex- however, has the drawback in radiation in contrast to the common the exact position of the ship must radio frequency methods now used. be known before further action can It is extremely simple and can be take place. Essentially, it consists controlled to such en extent that de- of a method of dragging a cable tection beyond the distance predeter- over the bed of the river until it mined is impossible (according to the comes under the stern of the vessel. inventor). It consists of two react- This cable is then replaced by a ances into which are placed iron heavy chain. Immediately another cores; for sending a telephone coil is chain is thrown across the top of used, shunted by a variable con the vessel so that it will lie perhaps denser. The transmitter and battery 100 feet forward of the position of are tikewis shunted by variable e.on- tent of vibration frequencies which the first chain obtained. This second dei,sers. Thus, the direct current, not chain is connected with the first are wanted. The presence of by a block which allows itself practically constant, induces no cur - natural vibrations are very objec- chain rent in the high tension winding, but to slide downward only. When, there- tionable even in telephony, as a re- is tightened, made to rise and increase or de- sult of which the higher tones of fore, the second chain crease in size and move forward at the voice are unduly strengthened it forms a complP`e harness around the same time to give the effect of tho still permitting speech. If used the ship or other feature moving to- in submarine signaling they would ward the front of the stage. A not transmit articulate speech, so large number of moving platforms by properly proportioning self -in- cause the illusion effect to be more duction, resistance and capacity in pronounced, at the same time a the circuit, the amount of sound ab- wider sea area toward the rear of sorbed can be regulated and the the ship is effected by gradually ele- diafram then made to vibrate sub- vating the waves, causing the illu- stantially correctly over an entire sion effects to take on the aspects range of frequencies, whereby clear, found in nature. In actuality, the sharp, articulate speech can be ship moves forward for about 10 ft. heard for distances of five miles, via the absorption system, whereas, prior Electric Furnaces. to this only indistinct sounds were (No. 1,324,156, issued to Feline Ja- heard. coviel lo. ) This latest invention is an electrical furnace wherein a series of Metal Cutting. grafite crucibles are imbedded in (No. 1,324,337, issued to R. E. powdered coal or gratte, thus con - Chapman and J. W. Kirk.) necting them in series. The pipe or A very clever patent was recently conduit communicates with the up- granted to the above mentioned in- per portion of every crucible. Molten dividuals on apparatus for cutting metal can bè poured from all of metals. It is of the simple arc - the vessel, gripping it firmly. As the crucibles at the same time. Great forming type in which a carbon many of these chains are lowered as heat is produced in this furnace be- connected to a generator creates an required in each case; the second cause of the relatively high and low arc at its point of contact with the chain only does the lifting, the first conductivity of the alternate layers when the operator speaks into the metal to be cut. The center of this chain going under the bow and act- transmitter he varies the resistance, carbon, however, forming the grafite crucibles and is im- has a hollow bore ing as the gripper. the intermediate packing. and a considerable potential A float actuated by hydraulic ele- prest between the antenna and the vators then raises the vessel. As ground. For receiving, a similar seen, vessel for the suc- iron core reactance is used and is will be the a re- successful operation should be in an either connected directly thru upright position or nearly so. ceiver or thru a vacuum tube for the purpose of amplification. Telescopic Tower. (No. 1,325,053, issued to F. C. Stei- Battery Connector Remover. dle.) (No. 1,316,485, issued to Fremont This invention is the latest in tele- S. Kay.) scopic towers for submarines and This patent is very clever and IC.P1 other uses. It is absolutely water- novel. Heretofore, in order to re- tight and air -tight and its telescopic move connectors from storage bat- running thru it, to which is con- means is acconiplisht by comprest teries and the like, it has been neces- nected an oxygen supply tank; thus Electric Keyboard. when the arc is started and the metal (No. 1,311,384, issued to William F. commences to fuse, advantage is Drew.) taken of the better cutting qualities This does not relate to calculating under the oxygen stream. This arc, machines only, but includes type- according to its inventor, will oper- writers and the like. We shall de- ate as efficiently under water as scribe the adding machine herewith. above. It consists essentially of ten solenoids which operate the adding machine levers. In addition, there are Submarine Boat Detector. ten more solenoids connected to a (No. 1,321998, Issued to Giovanni tier of the same number of plates of Emanuele Elia.) slidable nature in the series. When, It consists of a long rubber hose therefore, electrical contact is made about one -half inch in diameter by means of the stylus, two sole- suspended from a series of small noids are immediately actuated. One buoys at a predetermined depth. draws the slidable plate of that series This rubber hose may be quite long so that the plunger can only descend and as it is comparatively light, does a definite distance and the other not cause any great resistance upon system causes the plunger to descend. the progress of the ship. Should the submarine now run into the hose and cut it, the sudden outflow of water which has been pumped into it under pressure, would be instantly noticeable on the vessel's indicating apparatus. sary to destroy the posts by drilling them out. This device, however, leaves the center post intact remov- air. Valves opera ing on a pressure ing only the connector without in- principle cause the first and lower- jury to the original posts. It should most section to rise, carrying with it meet with favor with all storage all the other sections. When this battery repair men. The tool when reaches its extreme height the in- operated cuts two concentric zones. crease in air pressure causes the The inner cutter clears the solder valve to open and the second sec- from the periferal surface of the tion rises, and so on until the last is posts of the battery, while the outer completely elevated. It also carries cutter clears the solder from the with it guys so that there is no dan- wall of the eye on the connecting ger of it being damaged during the strip. In this way the post and con- process of extension or when storms necting strip are completely saved. are encountered at sea. 1288 ELECTRICAL EXPERIMENTER Apri'], 1920

WITHWAMATEUR

Our Amateur Laboratory Contest is open to all readers whether subscribers or not. The photos are judged for best arrangement and efficiency of the apparatus. To increase the interest of this department we make it a rule not to 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 eac91 "Honorable Mention." Address the Editor, "With the Amateurs" Dept. "Ankaaeuz ILdnolcatopy99 Contest THIS MONTH'S $5.00 PRIZE WINNER - table, the wall, or the switchboard. On the latter, I have a lamp. battery -fan, ignition coil, telegraph apparatus, "shocker" and a PAUL WALTER motor. I SUBMIT herewith, photos of my Electrical and Chemical Labora- These are controlled by a selective switch. The `juice" is tory. I do my own photo work and produce many odd effects obtained, at present, from dry cells. These are controlled by with my home made apparatus and am equipt to enlarge, reduce rheostats and by a switch, so that any number may be used. and copy anything from an atom to a battleship. I manufacture a A good feature, is the combination telephone -telegraph line. For glue which will mend anything but a broken heart. telegraphy, I now use a key (mounted on the table) Radiotone, con- I have a motor denser, and Pony receiver, while at the other end, a friend. has a -driven chuck upon which I turn up many things to regulation Morse telegraph outfit. For phoning, I use a micropii ne, be used in the making of coils, apparatus, instruments, etc. It will . drill holes in any metal or wood and can be used to polish brass designed from one shown in the December, 1916, EXPERIMENTER -a parts. This little tool is really necessary to any laboratory. A goad phone and bell. On a shelf is an arc light run by 110 volt A.C. current with a water resistance and fuses. I amnow working on a asset for a well conducted shop, is to have everything arranged is detachable sonic systematic order, so that when a, fellow is working or has an part, which can be fitted over the carbons, converting a idea. he will not be discouraged or tempted to be careless because the into a furnace when necessary. An eight point needle drop annuncia- tool he wants is not handy, or the piece of material he needs is way tor shown .on the wall in the centre is very useful for connection down under some transformer iron. I have everything labeled and with burglar and door mat alarms, thermostats, etc. in plain view. Each screw and washer has its special place, in my My workshop is equipt with all the necessary wood and metalwork- shop and I don't have to stop my work to look for an article. The ing tools. I also have a foot-power lathe which is not shown. The result is that I get something done, because things are where they chemicals of my Electro- Chemical department are kept on a shelf in suggest their use. Walter, 2725 Main my desk. I don't need a very big outfit as about all I do in this line, -Paul St., Ocean Park, Cal. is to experiment with wet cells, accumulators, electro-plating, photog- HONORABLE MENTION, JOHN G. SPOTTON raphy and occasionally I do some analysis. The upper shelf holds my library of about 30 technical books. What I value the most, tin. are $2.00 PRIZE PAID EACH "HONORABLE MENTION" my back numbers of the ELECTRICAL EXPERIMENTER, from Novem- IWISH to show in this article what can be accomplisht in a ber, 1913, to date. This indeed is a library in itself, and has been limited working space. I only have a small corner in a room. my "guiding star" since I first got to be an "Electrical Bug." john The apparatus that are permanently mounted, are either on the G. Spotton, Harriston, Ontario, Canada.

H ORABIE MENTION April, 1920 ELECTRICAL EXPERIMENTER 1289 nc EVERSON WESTERY®ENG

SUTURE NEWS NOT AS YET INVENTED NEWS FROM ALL OVER THE WORLD AND ELSEWHERE iI nnu I,Iw11O11,M,0111111111 I!I!!!1!I1! @III !IIIIIilnullll 'Mil N 1 ' 11\ w9P; 9 l nuo carow ..I_ ' "1' !ml IIIIII 11111111111111111 j II rrJ :F' pUIIIU ,:.b' 4 `b ; Ilv. w. ll (a® ® 11111CIIIIIIII1hIRCIUI101''," i : I IIIIG9lplllllll !' .I;lñ JII,F1I, u iryp II . ..1[0111 1. dlllt Ilpl jlÍI1IV1m .:.u.rmm I ull1le.l,

OLD MAN "H.G" AND HIS PERFORMING EDITORIAL WILD CATS TURNING OUT THE MONTHLY E.E. SPASM.

INSPIRED BY M. BLACK 2 D

Formula: A Ton of Brains, 20 Barrels of Ink, 2 Carloads of Paper, Hundreds of Telegrams (Radio and Cablegrams), 10,00E Letters, Photo- graphs and Manuscripts By the Barrel, Seasoned With a Dash of Electrical and Chemical Experiments, a Wild Night Ride or Two, Via Pullman, An Airplane Trip, Etcetra, Served With a Layer of Meringue Glace (Varnished Covers) and There You Have It-Your "Elec- trical Experimenter." s" JUST can't get over wondering did every month -well, here goes,, anyway: "Sure thing, that's my profession." I how that New York bunch keeps "Last month when I went East I made " 'How comer on turning out this sheet month it my business to call upon the E. E. outfit, "Well, you see, I am Warden of the jail after month," Bender queried while and you may believe me or not, but I'm of Berkeleigh, Cal.!" loafing -beg pardon -leafing over still dazed from what I saw, s'help me " 'That's fine. Now then on what busi- the latest issue of the EXPERIMENTER. Caesar. ness would you like to see the Sultan ?' "And," he continued, "it beats old Dutch, "Some fine Monday A. M. I trot down "Just a friendly visit." how Gernsback and his editorial wild cats to Fulton St. -which is the dead line of the "Just then the house bell clanged out manage to make each issue better than the town-and pull up short at "Information," the noon hour, and as I had no appoint- one ahead of it. Where do you think that where I throw anchor. ment with the All- Highest, I saw it would bunch gets all those ideas from anyway ?" "'Want to see the Editor. Name's Jazz be useless to get into his Wigwam and Jazz 'grew contemplative as he looked Stokes from Oakland, Cal., I mentions to next to his skin. So I invited the 'Info - wistfully over the broad expanse of the the cutie behind the switchboard. A couple Switchboarder' out for lunch, as a ruse. Pacific as it lapt its way toward 'Frisco hours later when she finally finds time to An invitation for lunch always works in Bay. He pulled a few times at his cigar give me the once over, she smiles expen- New York. So while she got her hat and before he replied with a sigh: sively at me and asks what in blazes I put on her outdoor complexion, I slipt "Tell you the truth, gents, I'd rather live want. I repeat the info. by the gate, vaulted a couple of brass in my quiet two by four in Oakland than "Oh, yes,' she chirps languishly, mani- railings and made a home run for the publish that nerve -racking, man -eating curing her nose with a powder -puff all the sanctum labeled 'Editor.' I pussyfooted shark that goes by the name of ELECTRICAL while, 'I remember you now, you are the in cautiously-which, however, wasn't at EXPERIMENTER, better known as Sperry Stoker from Coakland, Oklahoma. Ex- all necessary. There were three or four in Australia. And if Gernsback had the cuse me for letting you wait a bit longer. people in his office and no one paid slightest sense of humor he'd call it ELEC- Now what's your name ?' the slightest attention to me, so I sat Tlucnl, Exterminator, because it sure will "I repeat it a few times over. down. The illustrious 'Idea- Incubator' exterminate him sooner or later. No man "Age ?' she asks next. was very, very busy with a couple of can live and remain a human fountain of "Uncertain," I piurmur. artists, his secretary, the phone, the radio - ideas day in and day out like that bird, and "Was your mother married ?' phone and his managers. During the half not dry up in the end. "Not yet, she's a widow !" hour I was in that editorial bug -house, I `But you boys want to know how it's "'Have you ever been in jail ?' (Continued on page 1292) 1290 ELECTRICAL EXPERIMENTER April, 1920

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

LAMP BULB A LEYDEN JAR. proximately twice as strong as either cine dome by means of a telegraph key or switch (1039) H. Edwards, Deseronto, Ont., of the single units, as you mention; pre- operated by hand, or else a motor or slow writes suming that both South and both North speed vibrating relay may be rigged up to A. 1. While experimenting with Geiss- poles are placed together, i. e., both S.S. produce this effect. ler tubes, made from burnt -out lamp bulbs poles at one end, and the N.N. poles at the In regard as described in a former issue of your other. to the hardening of the steel, magazine, I will say you will do well to look up some noticed an odd thing which I Answering your second question as to good machinists' handbook cannot account for. The bulb used was the form of magnetizing coil required, on this subject, an ordinary Tungsten but in brief, it has been found that the lamp. The glass rod would say in the first place alternating cur- steel used should preferably in the center of the bulb had been shat- rent cannot be used, and direct current be a tungsten tered steel, and that it should be glass -hard in in some way, so I covered the glass order to have tip with wax and made a Geissler tube out the greatest retentivity for ,, magnetism. It is of it. The tube was attached to a static common practice for É ordinary magnets to heat the steel to machine - a capable of giving a twelve -inch cherry red spark, by a wire which was wound around DOLLA.2.5 and then to plunge the bar in the water; thus quenching it quickly and pro- brass end of the bulb and attached to ducing the positive terminal of the machine. A FOR. SO (E5 a practically glass -hard temper. short gap was left between the two termi- We take pleasure in recommending one of nals of the static machine and ASCIENTIFIC magazine is supposedly the best books on magnets, i. e., the work after operat- notorious for its dry reading. Still entitled "Experiments in Electricity and ing for a few ,minutes I pushed the termi- we flatter ourselves that the ELEC- nals Magnetism," by Sylvanus Thompson, which of the machine together and discon- TRICAL EXPERIMENTER can hold your our "Book nected the bulb. Then I picked up the attention without your yawning too fre- Department" can supply for bulb without touching the end. When quently. $1.65 prepaid. A very good book covering brass Of course you like to laugh-we all do. tempering of steel, etc., is entitled "Rogers' I was about fifteen feet from the static Sometimes we make you smile while you Machinists' ipachine I happened to drop my finger onto peruse the EXPERIMENTER. Perhaps Guide," which can be supplied sometimes you laugh out loud -at some at $2.15 prepaid. the brass end to the bulb and drew a spark of our "preposterous ideas" which we about one inch long from it. Rather sur- print here. And then of course the joke's prised I carried the bulb downstairs to the on us, because we were real serious! Now it occurred to us that we would science teacher of the school and showed like to print a column of real, original ONE OR TWO TELEPHONE RE- her the spark. This time it was less strong jokes every month, but here's the hook: CEIVERS BEST? and after two or three attempts it became The oke must be a SCIENTIFIC JOKE. No, this is no joke, we mean it! totally discharged. The bulb was certainly Anyone can print or re -print jokes, but (1041) A. Jarrett, New York, N. Y., in- a Leyden jar, and my hand was one coat- we want them with a dose of science. So, quires : ing. What had formed a second coating to till further notice we will pay $3.00 as a Q. 1. Which is the best, the single Bell hold a charge on the inside of that monthly lst prize for the best joke, and telephone receiver or this, together ex- $1.00 for each other one we print. with an hausted bulb? So you will know what we mean with a auxiliary watch case receiver. 1. Undoubtedly you are not aware "Scientific Joke," we print one here, A. 1. With respect to the efficiency of that the charge is retained in the glass, which we purloined from the "Baltimore the watch -case telephone receiver, which is and not in the coating of the Leyden jar. American ": commonly used and supplied by telephone LOGICAL. -"I want some good The highly ionized air in the electric bulb current literature." companies in different cities in order to acted as an internal coat, and induced the "Here are some books on elec- hear long distance calls more plainly, etc., glass to take on the charge inside, whereas tric lighting." would advise : the outside coat, viz., your hand, was con- Now of course, our readers can do much There is no doubt about it that the addi- better than this. So let's wait and see. nected to the earth thru your body. One reader can submit as many jokes as tion of the watch -case receiver helps very To prove that the charge is retained in he pleases. Even if it is old the joke is considerably. As regards the electrical the glass and not in the coat is very easily not necessarily barred or condemned. efficiency, you can rest assured that there demonstrated in a separable Leyden There is one rule however: The joke must is invariably sufficient current at the tele- jar. not be too technical; in other words, it The Leyden jar is charged, the coats care- must be readily understood by anyone. phone terminals to operate at least two re- fully removed by an insulating rod, and Not more than 100 words can be used. ceivers connected on parallel. It is the these, when away from the glass, may be Use only one side of the paper. same as connecting two lamps on parallel. touched impunity. Address Twice the current is required for two tele- with Should the fingers SCIENTIFIC JOKE EDITOR, be placed on both sides of the glass, a Care of this publication. phone receivers as would be required for slight crackling is soon heard, showing that one, but the editor of this department has there is some charge, which escapes very never noticed any depreciation of the speech slowly. However, if the coats are now re- reproduction when the multiple phone is placed and a discharger brought in contact either from a lighting circuit, or else from connected, when either receiver is tested with the inside and outside coats, a sharp storage or dry cells must be utilized for separately. Secondly the hearing efficiency crack is heard and a spark flies across the the purpose. A very powerful magnetizing is increased by this arrangement of two re- discharge ball and the knob on top, the coil may be made as follows for service in ceivers, as has been proven in wireless work, metal coatings acting as good conductors conjunction with this battery current. A where two receivers are always used. of the charge. brass tube, 54 inch inside diameter and In the first place, as you state, there is- measuring three inches in length, may be more sound produced, but the main and MAKING PERMANENT STEEL wound with 20 layers of No. 22 B. & S. most important thing is that you in this MAGNETS. gage, S.C.C. magnet wire. The magnet manner bring into operation the combined (1040) M. F. McCormick, Crown Point, steel may be plaped in the coil one after hearing forces of the two ears; which co -act Ind., asks the "Oracle": another and the current switched on, after in a very much better manner when they Q. 1. Several questions regarding per- each magnet is placed within the tube, the are both acted upon simultaneously by the manent steel magnets ; these bar magnets steel bars being magnetized from % to / same sound, as compared to the action when measuring 4x/x3 inches. minute. The strongest magnetization has one ear is affected by the sound only. Be- A. 1. Regarding first question, would been found to take placé in such steel bars sides, as you state, there is always trouble say that a compound steel magnet made when the current thru the coil is inter- due to external noises affecting the open up of two separate magnets, would be ap- rupted at short intervals. This may be or unused ear. April, 1920 ELECTRICAL EXPERIMENTER 1291

Carbon Remover An occasional dose will stop that knock- quiet the motor -and save the batteries. You can do it yourself in ten minutes. iirCar It isn't fair to yourself or to your car to run it without Johnson's In liquid for m Black -Lac is the and easy to use. any attention and then sell it at a big loss. With but ideal top dress - W i 11 ordinarily ing. One coat seal leaks in little effort you, yourself, can keep your car in such imparts a rich, from two to ten black surface minutes. condition that the depreciation will be very slight. We just like new. offer for your use Johnson's Car Savers. No experience is necessary for their use. They can all be applied by the amateur with perfect satisfaction. Johnson's Car Savers are of the very highest quality that can be produced. You will find cheap make -shifts on the market, but when you insist upon Johnson's you are taking no chance, for all of our preparations are fully guaranteed.

Anto -Lak A splendfd elastic varnish for perma- JOHNSON° bodies, hoods A quick, nent, inexpensive and fenders. A repair for tubes coat w i l l in- and casings. Can ,»wem crease the value be applied in Car of your car three minutes at from 10% to a cost of 2 cents. 35 %. Dries in Start today to reduce the depreciation of your automo- 24 hrs. bile. An hour or two every month and Johnson's Car Savers will prove their value in-dollars and cents when you come to sell or turn in your car. Johnson's Car Savers have been on the market for several years. Millions of cans have been used by motorists everywhere with entire satisfaction. For years our employees have been our partners and share the profits. Because of this personal interest unusual care and skill enter into the manufacture of the Johnson products-overhead is reduced to the minimum and we are enabled to sell at a very slight increase over pre -war prices, notwithstanding the tre- i mendeus advances on all of our raw materials. It seeps between and the springs, thor- Representative dealers and jobbers all over the world handle oughly lubricat- Will remove pits Johnson's Car Savers. Don't handle ingthem. Makes and foreign sub- accept or unknown substi- your car ride stances from tutes. Write for our booklet "Keep Your Car Young" -it's free. easier, reduces valves, giving a the liability of velvet seat. Will spring breakage. not cut grooves. S. C. JOHNSON & SON Dept. E. E. 4, RACINE, WISCONSIN

You benefit by mentioning the "Electrical Experimenter" when writing, to advertisers. 1292 ELECTRICAL EXPERIMENTER April, 1920 Science With A and By EVERSON WESTERLING (Continued from page 1289) Knorr never got the hang of it how he made him- to make fine reading-full page drawing self understood with them, or they with showing those inventions, what? him. I never knew if he talked to them, " 'Finally, you yelled so loud that my to the phones, or to himself. ears hurt. Seems as if the acoustics in my "Howard Brown, the gink who smears office are too good -how about two pages the monthly canvas cover was discussing on acoustic freaks -echos- strange acous- Your the next spasm with the Pasha. Brown tic phenomena -full page illustrations how wanted to know what the main color was to do it -there are your 8 pages -no, don't to be. thank me, call me up later if you need " 'Weather Bureau,' yells the High -Chief more ideas!' into the phone. He gets it in a couple of "I had heard enough. I collapsed right seconds. 'What sort of weather will we then and there. After I came to a couple have next month ?' he bawls. 'Rain, all of hours later, I slunk out of this idea - Man month, you say? O. K. Fine.' monster's office. He had never even seen -to sell to him " 'The cover will be sky blue,' as he me. turns to Brown. 'As it will rain all next After I had sufficiently recuperated I t-to employ him month, people will be tickled to see a blue thought I'd waltz up to see this Secor -to direct him sky, even if it's only on a cover. We ought bird. He looked -or rather sounded prom- to sell a couplo thousand copies on that ising. ' As I had no appointment with the If you should seek for quali- the one big argument alone!' gink I bribed the elevator brigand who fication that has made for the success of "'Fine,' says took me up, hidden in a big ashcan, which Schwab, Carnegie, Morgan and others, the paint cuckoo. 'Now what's the ?' just went up after having emptied its load you would find that they knew men; subject their ability The Grand -Duke scratches his head of rejected manuscripts on the paper to gather around them the dealer's wagon. right men for the thoughtfoolishly while he toys with his right position more telegraph instrument. than any other factor contributed to Just then a nice I was dumped onto the associate editor's their success. ripe tomato comes sailing in thru the open floor and crept to the door labeled window and lands squarely on the Mikado's Until you know how to judge men cor- bean. Quick a flash he rectly, you cannot sell, direct or employ like turns to Brown, and chuckling gleefully says, while HARRY WINFIELD SECOR, them to the full extent of your ability. E.E. I. R. E. S.O.S. P.D.Q. You can know. blotting up the ketchup with a few blot- It is easy. Mr. Wilson ters: M. Taylor has given an infallible, ASSOCIATED EDITOR correct "'That gave me the idea. The who and simple method in his new book Subject will guy thinks he does all the be an artificial big steel man. Show him work AND DOES "The Science of Approach" working in a field ; paint him red -like He classifies all types of men and shows you this tomato sauce. Good combination - the best way to appraise quickly the minds of red steel monster with a skyblue back- Thru the door came murderous sounds, men of various types, to determine their in- ground. People will be interested in him, and I had already turned back on second clinations, their process of thinking, their basis thought, but a tall young giant of judgment and decision. now that help is scarce. Open his back who wore a to show the propelling machinery inside of sign on his hat "Field Editor" rushed up Get This Key to Men's Minds him -ah yes -wireless aerial on his head in a monstrous haste. He collided with me and Stop guessing. Know why people like you and and in foreground radio man with a lot we both burst thru the door into the why they do not. Learn how to make them of wireless junk, who directs the auto- sanctum. However, he paid not the slight- like you. Be able to recognize the type that maton's movements in the field.' est attention to me, so I sat down and thinks slowly and acts slowly, the type that looked scenery. thinks quickly and acts quickly, the emotional "Fine, wonderful," we all applauded. at the type, the mercenary type, the generous type and "That's going to be some cover," yelped Miscellaneous, gum chewing, powder - all other types. You can realize what an ad- the manager. our competitors will puffing damsels sat at various desks manip- vantage this means to be able to do this. The "All largest firms in America are adopting Mr. die of envy, but how on earth do you get ulating their keys. Taylor's method. You, too, should have the all those ideas ?" On the floor lay a long- haired cuckoo, knowledge this book contains. "'Simple,' chuckles the Rajah, 'the "artist" painted all over him. The associate editor was just then an Mr. Taylor Has Agreed to Send it on tomato gave me the idea of course ! Don't drumming Five Days Approval you see, tomato -auTOMATOn-and where editorial point or two into the artist's anatomy. The Grand Vizier was waving Your does a tomato grow? In a field! There opportunity is presented in the coupon a drawing hysterically at the unfortunate below. Use it. All it requires is a little you have it, automaton working in field. initiative to determine whether or not "The Next !' rat on the floor and lambasted him for Science of Approach" will benefit you as greatly the associate Editor some minutes soundly. as Just then Secor, it has benefited other men. You take no in ! ?X risk in determining comes in with a bang thru the loud talking "What X RRR do you mean by this. Sign and mail the crabbing my attached coupon TODAY. telephone on the wall : X ! ?! 1 - .... - --!xx illustration this way R !X? Wow-R- rhrrrrrr...what iii thunder do RRRRrrr Wow Bang Ziz look at you mean by adding 8 more pages to this this face -what will our readers think of infernal sheet, ain't we got enough now... me -I didn't want a pig's face -I want a r- r- r --R -RR X ! ? **-can't possibly do MAN'S face -wow, bang, Rrrrrr !X MORE. Killing myself now. Absolutely and look at this electric current-why, it Impossible to do more work -I quit right looks like a bunch of spaghetti, you fish - here -W ah- wow- wow -whizz -bang- faced, enaemic son of a rainworm. And "and he's gone !" then look at this thing-Lord have mercy "But the High- Priest thru it all keeps on his brain that he hasn't got. Didn't I on smiling; it seems he likes those gentle tell you to put a derrick here-and look outbursts. No sooner has the enraged what this poor idiot of an evaporated mol- editorial bird ceased fluttering than the lusk-brained flea puts in its place -a HER- Grand -Turk presses a button and chirps RING, instead of a derrick. And here into a mouthpiece: we're scheduled to go to press at 4:39 "'Great stuff, Secor. That talk of yours A. M. and the drawing must be made over gave me a bunch of ideas to fill those eight again. Whizz, Bang, BANG, WOW pages : You spoke about killing yourself ; X! ?XX! ?X " why not send Kraus up to Sing -Sing and Just then the loud talker with the 'voice get some recent dope on how they electro- of the Editor-in- Chief's started: cute the murderers up there -good for two "Listen Secor, I got a glorious idea, for you to Best had WILSON M. TAYLOR, Inc. pages with a full page washdrawing show - work out. I've since five 35 West 39th Street, New York City ing how it's did! minutes ago. Let's make a $100 prize con- please send toe Copy of your book. "The Science of "And you said "What in thunder," didn't test what to do with discarded mouse traps. Approach." on 5 days' approval -enclosed find $2.00. I the matter Readers like these contests besides these It I decide not to keep the book, i will return same you, darling? Well what's with - to you within 5 days and you are to return the $2.00, making a full page drawing showing all popular contests bring in from 6 to 9 tons without question, the different stages of a thunderstorm- of paper which we can sell to the paper Name good for two pages. deal "'Then you said absolutely impossible, But the voice was cut dead by a large Address E. E-4-20 yes, no? Well; two pages of good stuff inkstand that the irate Secor threw at the P.S. if you prefer, we will send took and you can I showing historical instances how inven- loud talker. i{ send us $2.00 or return it in 5 days. L _-___ -- tors made the impossible come true ; ought (Contniued on page 1294) You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1293

Send for this free lesson which explains let us tell you about the Chicago "Tech" method of teaching the Chicago "Tech" Draftsmanship by mail. Positions at big method. The free salaries are now waiting for competent men. lesson will show Even draftsmen of limited training and you how well experience are snapped up and paid equipped you are to good salaries. If you are dissatisfied follow Draftsmanship. Enroll with your opportunities, learn Drafts- in the course only if you decide that you manship. Chicago "Tech" will train you can take it up to advantage. No cost, in the most practical way in the short- no obligation on you to make this in- est time. Mail the coupon today and vestigation. Send the coupon. $25 to $100 a Week Draftsmen always command good salaries. And now when American industries are to be called upon to meet vast foreign and increased domestic demands, the opportunities are greater than ever. This is the time for you to prepare for a better position -a higher salary. Come to the College or Learn At Home Hold you present position while training. Our experts will instruct you by mail. Only your spare time is required. You are directly under practical draftsmen and, engineers. You are taught exactly the work required in the drafting rooms of big concerns. No time put in on unnecessary studies. This means thorough instruction and early graduation. Easy Payments The fees for Chicago "Tech" Courses are very moderate -and you can pay on easy terms. And also. you obtain in a few months what it would take several years to acquire by ordinary methods. You can get an early start. You are soon ready to take a paying position and to quickly get back the cost of your course. Then keep on earning more. FREE Instruments Every student of the Chicago "Tech" mail course in Draftsmanship receives this set of instruments, or a cash credit in case he already has a set. These instruments are of the same make and sizes as are used by high salaried experts in drafting rooms of factories, shops, railroads, etc. You use them . while learning -then take them right into your practical work. Auto and Gas Engine Course Send the Coupon -Now All about automobile mechanism -its construction, operation and REPAIR - The sooner you are prepared the sooner you will be holding a job that pays a large salary taught by mail. You train directly under the Chicago "Tech" automobile ex- and opens the way to advancement. Many executives, general managers and superin- perts. Splendid opportunities open now. Send coupon and get all the facts. tendents began as draftsmen. Learn All This in Spare Time Other institutions ask you to pay first -and then to find out later how well qualified Principles of the Automobile. about how them. you are for this profession. We send you the free lesson first and place you under no obli- Every point made leer bout the basic etcirculating oil systems.too e t Spas gation at all. Discover your qualifications before you pay anything. p i'lem of ulsion- steam, gas and frent care explaied.D e and tables. Means care. Power tranamieaion systems Cooling systems completely Ì nnciaNd,etc. The coupon in pleasure and commercial can, etc., etc. Batteries. Electrical principles ex- will bring theTest Engine,. plained. Instructive diagrams of saving and Lesson, free. Al- Gasoline All about the n Coils, condensers, vibrators, CHICAGO different type.. A complete coure in gas dom. so TECHNICAL COLLEGE, engine construction, operation and etc. etc. information repair. Nucal o Ignition. Principles and about the profes- 445 Chicago "Tech" Building, Chicago Power Plants and Transmissions. and and Application of power bY 4- 6-812 cylinder praactical operation of 'rio types sion of Drafts- Without obligation to me, please send me your FREE Test Lesson ea Typesof elutehe., anon' v terns with diagram...Generation of other interesting literature covering the subject indicated below. drive', rent. ES highand low tension, manship and de- e fe , tc. Mark X opposite work in which you are especially interested. Carburetors and Fuel Supply all explained. every tailed facts about St and Lighting Systems.at D Architectural Drafting Plan- Reading- Building Systems. All methods demonstrated. All modern methods. Starters-spark, me- Chicago "Tech" Fuel values. How to test. G000line and Monica!, air, amtylene electric, battery - methods, the fees, Machine Drafting Plan- Reading -Shop Men Regulation, care and man- show in detail with ding and full e - terms, etc. Mark Electrical Drafting Estimating agemixtures.ent, etc., etc., etc. planation,. Charging. Motor and geser- with X the branch Lubrication and Cooling. All ator adjustment., etc., etc. you are interested in Structural Drafting Surveying Know How to Find and Fix Troubles -or if in doubt about Sheet Metal Drafting Map Drafting instruction high start a which course to Builders' Course Autos and Gu Engine. business. Big den trainedrepair menrk.d mens who know to Inspect cars. take, write a letter This course makes you. proficient. Prepares you to take a job as an expert. No enoug stating facts about competent men now available. yourself and asking Name Send the coupon and get catalog and all information our which easy advice Ñ'RITE about the Course, the ,mall fee and the terms. will be freely given. Address All this sent on request. Mail coupon now. Mail either the coupon or letter today. City State 445 Bldg. Ch icago Technical College Chic cagoT, l ch" College or Home Study? State which

Yon benefit by mentioning the "Elec tical Experimenter" when writing to advertisers. 1294 ELECTRICAL EXPERIMENTER April, 1920 ScIlence WHh A Bang $1.00 Postpaid (Continued from page 1292) "That'll keep him quiet for a while," and test tubes he composed an odor sonata SHAVES WITH fumed the august Vice -Chancellor. Turn- in B- sharp. I felt myself transported from ing to one of the female inmates of his the perfume of a vamp's boudoir, to the GILLETTE BLADES cell at his elbow he growled: Chicago stock yards, thence to a sweet "See, there he goes again ! Ideas, jasmine and rose field, only to be hurled equal to any $5.00 safety razor. IDEAS, nothing but ideas all day and immediately into the agonizing stench of a night long. Any idiot can have ideas, but glue factory. does he work 'em out? Not on your lip- Before I had recovered there was a rouge! I'm the crab that does the dirty slight explosion of one of the formulas, work, and then I have to wrestle with this and a large brick came sailing my way. scum-pointing to the prostrate form of It knocked me down flat, but the odor the artist -so the readers will know what liberated by the explosion soon revived me. it's all about. And then, five minutes be- Coughing, puffing and sneezing, I galloped fore going to press that Editor -in- Cheese down the stairs forgetting entirely to in - countermands the order and sings out that troduce myself to the Wrinkle Professor. he thinks a contest of discarded straw - I went down six flights of stairs and cast hats would be preferable to old mouse anchor on a door mat resting before a door traps -" , ,; neatly smeared: Just then there was a comparative lull while His Majesty came to blows with the Field Editor, because the latter hadn't ROBERT W. DEMOTT fielded about something or other. (accent on the Dee) I took the occasion to approach the Advertising, etc. Rogers Bros. new safety razor is as Lady in Waiting. to his Highness. nearly perfect as any safety .azor can "Enchanted inmate," I ventured, "could This be made. No expense is spaEed to make I speak for a few seconds with the Chief office was mostly desks. A whole it the very best offer to t1 ê users of forest of them. The inmates of the dormi- of the Harem? Name's Jazz Stokes from tory high -grade safety razors. California. Tell the Señor I am here to when they wanted to cross from one state to the other used an overhead trolley Note the exclusive "Hexagon Handle" talk an business, but if Monseigneur is too busy, I will wait awhile." and a rope about the neck. This was by with a guaranteed double silver -nickel far the most elaborate Harem of the whole Electroplate throughout. The Lady in Waiting gave no sign of joint. The approval, either negative or positive, so I types varied from the opulent oriental to the Indian version of a Totem took the occasion and made good my threat. Pole. Being this Coupon Now I waited. I got even, however, because I in the advertising office, they pulled out my stopwatch and timed her believed in advertising: bare arms, bare D. A. backs, and neat ankles were well adver- R. Sales Company gum chewing. She batted a high average. tised. By As a matter of fact she could chew faster their flashing white teeth you 2521 17th Ave. So. saw at once that they were using a widely than the rest of the ward inmates. advertised MINNEAPOLIS, MINN. Just then a herd of draftsmen, photo brand of toothpowder. They all engravers, boys with printer's proofs, pro- wore expensive smiles of the well -known Enclosed find one dollar for and advertised brand : "The smile that fessors with manuscripts in one hand and won't your special safety razor offer bills in the other, descended upon the come off." un- The Chief was doing an elaborate War fortunate Secretary of Labor. He singled Dance, Nome out one of the draftsmen who was twenty- accompanied by the tam -tams of four hours overdue with his drawings, and the typewriter keys. .4 ddress Thomas A. Edison and Nikola Tesla, threw a bulky "Encyclopedia Germanica" who had at him. It caught the victim amidships, and a story running in the next issue as I begged humbly to be allowed to have their stood behind him, he caught me well articles run "next to pure advertising." 1_..,_--111------1 on my starboard side. We' both had a Edison pleasant sail the wanted to have most of his story thru door and before land- sandwiched in between Correspondence BATTÉ R'Y' C'H,AR;GbN,G ing, the draftsman introduced himself. Schools and Patents "That's the second time he me because he was cuckoo threw out on them, while Tesla, having more aesthetic Pl-FITS Ì this week, but I don't mind it. I carry ac- inclinations, cident insurance wanted his story to run along- -and he needs the exer- side the Wireless Ads and the High Fre- cise, poor boy-" quency Machine Ads. These $150 to $300 Profit Every Month On my way down I stopt at a door being his in- DO YOU WANT IT? labeled ventions, he thought it was no more than You can get it with an IM Charger. Sturdy, reliable, right that his story should be nothing to wear out or break, No burnouts or expen- well gar- sive renewals. Charges batteries for 10c to 150 each - nished with them. customer pays 75c to $1.50. Figure those profits! This But the Chief of the Tribe was season brings biggest business. Start NOWT S. GERNSBACK obdurate. WHICH ONE DO YOU NEED? He wouldn't listen. He said the other CIRCULATION DEPT. writers must have a show, too, and so on WRINKLES & FORMULAS and so forth. Finally Edison hit upon a fine idea. He would pay for the space alongside the ads and run his story in that On entering softly I found this worthy space. Before the Advertising Admiral flanked on all sides by many female as- had recovered from his surprise, both Edi- sistants and keybangers all equipt with son and Tesla had planked down a thou- gas -masks. Unlike the other offices, a su- sand dollars on his desk and flown the coop. preme quiet reigned here. It took me some The only comment the General made minutes before I could make out the form was : "Chump that I was: If I had only 32 of the of the ship. in HB 500 -Watt Charger- HB -Battery Charger -. Captain Clad an thot of it myself, I could have played those Recharges 1 to 32 6 -volt Recharges 1 to 8 0 -volt acid -stained duster, he was sitting behind birds against each batteries at Uses batteries or equivalent at other and gotten double a time. a time. Four separate a curious desk arrayed with every con- the rates !" power from lines now in charging lines, each capa- your garage. Should pay ble of charging up to 8 ceivable piece of junk, chemical glass- Just then six or seven trembling men $100 to $200 profit a batteries. Ideal equip- ware, magazines, bottles, shower bath, mis- in. I month. A big money- ment for big garage or stalked soon saw that they were big maker for a small bat- battery service station. cellaneous cats, minerals, one or two gross advertisers of the magazine. Their con- tery business. Will clear as high as $250 to $350 a month. variegated ash trays, each with a legend: tracts had run out at 6 A. M. that morn- Sold on Trial Under HB Absolute Money -Back Guar- No smoking; files-letters, mail and cross ing, having been in force for four long antee. All IIB Equipment is sold under our absolute cut-books, books, manicure guarantee of complete satisfaction. You run no risks. books, set, days. By that time a new rate had gone If not satisfied after using any HE Equipment 10 days, test tubes, goggles, gold fish, auto tire, and into effect which threatened to ruin them. you may return it and receive all you paid us. The HB monthly payment plan is an additional guarantee. too many other items impossible to en- Would the Secretary of State not allow Write today for full information about the HB Charger compass into the four ends of a compass. them to let the old contract run .for two that fits your battery business. The air reeked of the smell of putrefied HOBART BROS. CO. Box 48E, Troy, Ohl° more days? Or if not, would he not be codfish, but changed to the perfume of a satisfied with a raise of 450 %. 50 all duff. British Guiana, Cuba. China, dying rose the next, only to be transformed The Sheik pondered for a long time. India, Jamaica, Japan, Portugal, Vene- into the odor of .fragrant frankfurters a Then he called over one his STAMPS zuela, etc., only 100; 100 all die.. 15c; of Phoebe 1000 all cliff.. fine collection in itself, $5.00; 100 diff. second after. I then understood the gas - Snow's and asked for the latest time table, U. S., 30c; 1000 hinges, 10c. Agents wanted, 50% commission. List free. I BUY STAMPS. masks of his victims sitting about the office. better known as rate card. L, B. DOVER OVERLAND, MO. Just then by means of a dozen retorts (Continued on page 1298) You benefit bl mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1295 PoVitalize Your Tired Nerves!

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Enjoy wonderful, sparkling health ! Feel the thrill of the bounding vitality of youth! Increase your store of energy, revitalize your worn out cells, make every fibre of your body tingle with Vitality The Violet Rays send e spray of mild a new vim and vigor! All this you can have tiny currents through every Dart and of Vi -Rex Violet Rays organ, vitalising and invigorating through the magic right every cell. It acte like the refreshing in your own home! effects of a shower bath -and leaves you with a delightful feeling of bound- Violet Rays penetrate to every cell in the body, imparting that stimulating vigor which ing health and bouyant energy. brings the glow of health, tones up the entire system, putting life into over-taxed and sluggish tissues. As a quick relief from pain Vi -Rex has no equal. Its soothing rays quickly find the source of distress and afford speedy comfort. Headaches, nervousness, skin blemishes. and many other complaints vanish as if by magic through this marvelous treatment. You will be amazed at the splendid, quick results through the use of this wonderful new Vi-Rex Violet Ray Machine-right in your own home! OL RA The Ama2inq New Source of Beauty Violet Rays purify the scalp and Wealtlz , Energy and Beautr,. stimulate hair growth-a wonderful aid to beauty. Removes eczema, Pimples, blackheads, obesity-giving Vi -Rex Violet Rays are effective for a host of ment at home. the skin a smooth fine texture. free ailments. Physicians in all parts The operation of the outfit is simplicity itself. from blemishes disorders and and sallowness. of the country are adding this scientific outfit to Current from your electric light socket is trans- their equipment and recommending its use to formed into an effective healing agent as pleasant their patients. Beauty specialists have long to the senses as a ray of spring sunshine. It may Wm- Magic -Like realized its efficiency for inducing a clear and be used on the very young and the very old with- healthful skin. Until recently expense prohibited out the slightest discomfort. No shocks or jolts - Treatment For: the use of this remarkable health -building force in just a soft steady ray of violet light filled with an (Special equip- This is only a partial list of private homes. Now the practical, inexpensive abundance of health and energy. is supplied to you at a trifling cost if electric the many ailments that can be Vi -Rex Violet Ray Machine enables everyone ment of, this marvelous treat - current is not available.) treated successfully with Violet to enjoy all the benefits Rays right in your own home. 20 Home Self- Treatments FREE Asthma Goitre You don't have to take any risk in giving Vi- a Viabrator Barbers' Not Itch Insomnia Rex Violet Rays a trial. Take ao treatments in The Vi -Rex Violet Ray Boils Lumbago your own home. Use this marvelous machine Machine is not a vi- for If you do not brator -does not shock Blackheads Nervousness morning and night ten days. or jar the nerve ends. Bunions Neuralgia find quick relief-if you do not feel better, sleep Its effectiveness is ob- its Callous Neuritis better, look better, send it hack and you will not tained through offer is now open power of penetration - Catarrh Obesity be out one penny. This special not through manipula- but it may be withdrawn at any time so act tion of surface muscles. Chilblains Pains No feeling of soreness quickly! or exhaustion after use Colds Paralysis -only a comforting. Corns Piles Write for Free Book and Trail Offer agreeable sense of Constipation Pimples Write to -day for our free booklet describing the relief. Dandruff Pyorrhea wonderful Vi -Rex outfit in complete detail, and Deafness Rheumatism particulars of our liberal to -day trial offer. Find Vi -Rex Electric Co., will help you. Read what Earache Skin Diseases out how Violet Rays Dept. 44 hundreds of users say about the Vi-Rex and 326 W. Madison St., Chicago Eczema Sore Throat astonishing results which have been obtained. Eye Disease Sprains Please send me without cost or obligation your Learn why it is the most economical and practical free book describing your wonderful Violet Ray Falling Hair Tonsilitis machine of its kind available. You may use it to Machine. Hay Fever Whooping gain health, vitality, beauty! There is no limit Headache Cough to its beneficial powers. Mail the Coupon or Name send a postal. Do it now. Address Vi -Rex Electric Co., Dept. 44 326 W. Madison St., Chicago City State

You benefit by mentioning the "Electrical Experimenter" when writing to advertfsers. 1296 ELECTRICAL EXPERIMENTER April, 1920

other news these past few months -so many items of big interest to our readers-that RAI WAY my little sermons temporarily "got the gate ". T FIG (Bet you never even noticed that they weren't in.) IN ECTORS And so your letter remained filed away in a special folder and, frankly, SOCIATE it slipt my mind. It wasn't until Friend Secor, Boss of the 01 BIG 2MEN Ink Slingers from the Editorial Depart- ment, just because he happened to be in That is what g ves them chances for Cincinnati, 750 miles from home, with a promos on. They start in at a good hole in the magazine, and no news to fill it, salary $110.00 a month and expenses. AN OPEN LETTER TO MR. stuck No. 5 of my little talks in the Novem- The work is important, for the safety of ber issue. But lots of thousands depends on their vigilance, And THOMAS REED. other things just as when they do their work as we teach them bad happened to that issue -that one we they attract the favorable attention of their Dear superiors. Promotions then are rapid. Mr. Reed:- printed out in Cincinnati while the printers A long time ago you wrote me this letter. were on strike in New York. Learn This Profitable Profession Anyhow it did one good thing All you need is a common school education I'll reproduce it here because it's so long -it re- for entrance to our three-month's course. ago you probably have forgotten it. minded me that I had a letter to answer. which is easy to learn at home during your So I got busy and spare time. Take the initiative now, while by exerting every pull I the demand Mr. R. W. DeMott, could spring for Railway Traffic Inspectors is Advertising Manager, got the loan of part of two so good. THERE IS A BIO DEMAND IN THIS FIELD. columns in this issue. We know of fine openings for our graduates. The Electrical Experimenter, Many who started our course a few months New York City. Mr. Reed, your point is well taken from ago now hold positions. Dear Sir: - one standpoint. But here's the big rub in OUR BOOKLET tells of this ideal vocation I was interested in your address to the the mail order field. Suppose -out in the big out- doors -bow you associate readers in this month's Experimenter, and you buy some with big men -how you can earn an excellent will bring to your attention a little sugges- goods from New York. You live in Boston. salary from the start-how you can climb to Parcel the very top. The opportunity COUPON tion which I think.you may be glad to have. Post rates are cheap between these (below) is your key to a better salary now and You will understand that the incident re- points. Now suppose someone else a much bigger future. Why not send it today? lated in the enclosed letters was to me living Remember you start at $110 a month, and nothing more than an annoyance, but if the in San Francisco buys the same article. Do WE SECURE YOUR POSITION. practice is a general one of this advertiser. you want to pay part of his parcel post or Standard Business Training Institute, it must be causing real disappointment express charges ? That is what it would BUFFALO, N. Y. among our readers, most of whom are boys amount with little money to spend. My suggestion to if transportation charges were Please send without obligation tome, included in the price. your Booklet D119, explaining your is that you require all advertisers to state The manufacturer or Railway Traffic Inspector's Course. that their merchandise is `postage free" or seller would have to add an item for ship- Name else give the weight or something to indicate ping Andreas that postage is extra. that would constitute the average ship- In the case referred to I assumed that the ping cost for all his sales. That means that price of 50c on these ringers included post- the man nearest his plant would pay part of age. The advertiser sent me the ringers the shipping charging me the 30e postage as an extra to expense of the man far away be collected C. O. D. As the cost of the and the one at a great distance would get MARKO merchandise was only $1.00, the 30e extra his goods more cheaply than he should. charge was quite annoying. It also gives For this reason STORAGE BATTERIES this advertiser an unfair advantage, because it is customary in the mail ARE GOOD -TRY ONE his prices look lower than they really are. order field to quote prices net (without I have no doubt that the advertiser transportation charges). Paul M. Marko & Co., Inc. omitted the postage information thru 1402 -1412 Atlantic Ave. oversight, but I don't want our boys to feel And so it has become a recognized fact Brooklyn, N. Y. "stung" in the slightest degree when they that most mail order concerns require the answer our ads, which are not the least in- shipping charges added to the cost of the teresting part of the magazine. There is a goods chummy atmosphere about "E.E." which or else they ship "charges collect." ARE YOU BASHFUL, TIMID. extends to the ads to quite a degree and It is pretty safe to assume that unless the Self Conscious, Embarrassed in Company. Let us tell which I should think the advertisers would price of an article is marked postpaid the You how you can overcome these troubles and acquire find it to their interest to cultivate. price does not include the Poise, confidence assurance and a magnetic personal- Very truly yours, transportation ity. Address The Ventas Science Institute, 1400 (Signed) Thomas Reed. charges. Broadway, Now York, Desk 15. It, seems to me that it is more my duty Now, Mr. Reed, I want to apologize first to explain this to our readers rather than off for not having answered sooner. The to try to change the advertisers' policy. Printing point you bring up is so important to our Don't you agree? We certainly don't Oarde.circulara, la n,book,paper.Chem Press want Larger TLS Job press $lto. Have money. Print readers that I thought the best way of any reader to feel "stung" when he buys ell for others, big profit. All easy rules sent. .t. Write factory ror press oatalog,FYPE,oards, answering your letter would be thru this from an advertiser and it is my aim to keep ey.reesL os eta THE PRESS DO.. D -47. Merld.n.Conn. column. But there has been such a rush of (Continued on page 1326) Sole NEW MOTORS English Agents FACTORY GUARANTEED - ALL SIZES - IN ORIGINAL BOXES for _r ,.twKw nuo To Buy New Guaranteed Electrical g Your Opportunity Apparatus el Standard Manufacture. ELECTRICAL Single Phase Motors EXPERIMENTER Charging Generators Polyphase Motors SCIENCE AND INVENTION 111.510 volts. A. C., 60 cycle, Suitable for all lighting R and 3 pilaw, A.C., 49.0 y, Battery Charging Outfits 1800 R. P. M. with pulley Battery Charging 60 e. 1750 RPM.. complete To operate on A. C., 60 cycle. single phase and Power Requirements. voltage as specified. P, 111 volt., indue- with base and pulley. We are sole Sllrolla,A.C., 111wan. distributors for 1/H.4 do,, fall load .Ion - - W24.50 owls. 11 amp. $16.50 11 retti, $40.00 .h N. P.. $42.50 wilhaut .wihhhaud W`t the ELECTRICAL EXPERIMENTER N. Po, -1 N r n_ IS roll.. II amp. $21.00 ,111 volts, A.C., IS/ wage, 1/2 n t1 a n $ 38.50 tl roll,, $6 8.50 with ,wiàhboud `PC1 in Great Britain. If you reside eiIiL amp. 2x.P.. $59.50 1, 1,l1 nw1 N i $24.50 I11ßll rail, A. C., nl wilt,, 2 pHuho,n m plp, soo- r $46 .50 anywhere in England, commu- to e, 2': imp. $24.50 2x.5, 21 volta, without ,wil,hboud $75.00'P 1 N: P., 111421 volts, reput- $72.50 nicate with Hl roltr, A.C., 211 rntr, 2l roll, us and we will see rio,, wish sliding Aare - `PV$67.50 I. volts, 12 amp. $38.50 $85,00 - 2x.P. wilhoul .wilchhoard - that you are supplied each H. P., I II-!tl roll` $84.50 w rear, 5 amp. $38.50 111volt:,A.C,275wati,,lirolli, 2 repuhion Biding Ana $108,50 without ,wilchbard $85.00WO month. 25 amp. .1N.P. 3 H. P., 1 ',112 wit.. I. rolls, $58.50 $12 rl .50 81 row, A.C., 511 wnla' repulrioe, .tiding Aue '$102.50 dt rolli, with ewitchboud $1 111 volts, I I imp. $58.50 I H. P., high speed, 7301 1 0.00 ,I4 Ç cric. Moving Picture R.P.M, ttl r $36 ne tom, A.C., 751 citi,, 1 /6 r . P.,1n, eliding Ana $1 $85.00 2 phase only V 50 $125.00 Issue P wilhoul the 64'50 pre Generator W 72 roll, cwitchboard WRITE FOR CATALOG. BARGAIN: IN MOTORS AND GENERATORS Specimen Copy sent post free upon SPECIA WASHING MACHINE MOTORS receipt of a postal order or stamps 4 H. 1,1 rille, For 6d. Address Dept. 7. P Á.C.,01 x'. Small Cm- vrrswr.. Carra EACH S.P., 1751 RPM. , IE Gn der,.Enwr 4 Complele,eord,plup s pulley , hers, E,r. set V,lu, SIE.SI Messrs. Geoffrey Parker MONEY BACK - GUARANTEE & Gregg 7 , !S' depnit required in all orders Balan,, C. 0. D. by Espreta SHIPPING TERMS. S;ghl eran with Bill al Lading mashed by height 62, The Mall -' MANUFACTURrnq DISTRIBUTER Ealing, CHAS. H. JOHNSTON, Boxl2 á West End, Pittsburgh, Pa. London. W.5 air 6. ,1 You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1297

Are The Hours That Count OST of your time is mortgaged to work, meals and sleep. But the hours after supper are yours, and your whole future depends on how you spend them. You can fritter them away on profitless pleasure, or you can make those hours bring you position, money, power, real success in life. Thousands of splendid, good- paying positions are waiting ini every field of work for men trained to fill them. There is a big job waiting for you-in your present work or any line you choose. Get ready for it! You can do it without losing a minute from work or a wink of sleep, without hurrying a single meal, and with plenty of time left for recreation. You can do it in one hour after supper each night, right at home, through the International Correspondence Schools. Yes -You Can Win Success in an Hour a Day Hundreds of thousands have proved it. The designer of the Packard "Twin Six," and hundreds of other Engineers, climbed to success through I.C.S. help. The builder of the great Equitable Building, and hundreds of Architects and Contractors, won their way to the top through I.C.S. spare -time study. Many of this country's foremost Advertising and Sales Managers prepared for their present positions in spare hours under I.C.S. instruction. For 28 years men in offices, stores, shops, factories, mines, railroads -in every line of technical and commercial work -have been winning promotion and increased salaries through the I.C.S. Over 100,000 men are getting ready right now in the I.C.S. -YEAR OUT HERE- --- way for the bigger jobs ahead. INTERNATIONAL CORRESPONDENCE SCHOOLS l BOX 6226, SCRANTON, PA. Explain, without obligating me, how I can qualify for the position. or in the Your Chance Is Here! subject, before which I mark X. ADVERTISING ELECTRICAL ENGINEER MECHANICAL ENGINEER No matter where you live, the I.C.S. will come to SALESMANSHIP Electrician Mechanical Draftsman your Traffic Management Electric Wiring Machine Designer you. No matter what your handicaps, or how small BUSINESS MANAGEMENT Electric Lighting achine Shop Practice means, we have a plan to meet your .circumstances. No Private Secretary Electric Car Running Boilermaker or Designer Commercial Law Heavy Electric Traction Patternmaker matter how limited your previous education, the simply Certified Public Accountant Electrical Draftsman Toolmaker textbooks make it Higher Accounting Electric Machine Designer Foundry Work written, wonderfully illustrated I.C.S. Railway Accountant Telegraph Engineer Blacksmith easy to learn. No matter what career you may choose, some BOOKKEEPER Telephone Work Sheet Metal Worker needs. Stenographer and Typiat ARCHITECT STEAM ENGINEER one of the 280 I.C.S. Courses will surely suit your Good English Architectural Draftsman Stationary Fireman Window Trimmer Contractor and Builder MARINE ENGINEER Show -Card Writer Building Foreman GAS ENGINE OPERATING Sign Painter Carpenter Refrigeration Engineer Make Your Start Now! CIVIL SERVICE Concrete Build, r Metallurgist or Prospector Railway Mail Clerk PLUMBER L STEAM FITTER CIVIL ENGINEER Mail Carrier Heating & Ventilation Surveying and Mapping When everything has been made easy for you -when CARTOONIST Plumbing Inspector R. R. Constructing in the quiet of your Illustrator Foreman Plu-ber Bridge Engineer one hour a day spent with the I.C.S. Perspective Drawing CHEMIST SHIP DRAFTSMAN own home will bring you a bigger income, more comforts, Carpet Designer Analytical Chemist Structural Draftsman Wallpaper Designer Locomotive Engineer Structural Engineer more pleasures, all that success means, can you afford to Bookcover Designer Roundhouse Foreman Municipal Engineer let another single priceless hour of spare time go to waste? TEACHER MINE FOREMAN OR ENGINEER NAVIGATION SD.aI.e Common School Subjects Coal Mining Motor Beat Ramer Fres.h Make your start right now This is all we ask: Without High School Subjects Metal Mining AGRICULTURE it up Mathematics Assayer Fruit Growing Italian cost, without obligating yourself in any way, put AUTOMOBILE OPERATING TEXTILEOVERSEERORSUPT. Vegetable Growing to us to prove how we can help you. Automobile Repairing Cotton Manufacturing Live Stock & Dairying Auto. Electrical Work Woolen Manufacturing POULTRY RAISER Name Just Mark Occupation and Employer land Mail This Coupon Street and No

City awn. 1

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1300 ELECß`EiCAi, EXPERIMENTER April, 1920

Telegraph, Ca ., Reanf`i Make Your Own Radio ICIlspiiiltEChes ELECTRICAL APPARATUS ( (,nlitttted from page 1295) one word each in the address of cable or rsvvii

radio messages, irrespective of their length , -. ; rt jp, or the number of separate words they con- . ' instance, de Grace, New j. ' tain; for Havre ii ' York, East St. Louis are counted as one _ word each. In the body or text of a message, however, such names are counted and f.Ae 1 Be Draftsman! charged for 'at the rate of fifteen letters to Iii: 4 a the word in plain language messages ; at Make $30 to $75 a Week the rate of ten letters to the word in code Your name and address on the coupon brings this messages, and at the rate of five fetters great Cyclopedia of Drawing without a penny down. Pay only net shipping charges when books arrive. to the word in cipher messages. With these books and a low price "school set" of drawing instruments, obtainable at any store, a man can In dispatches written in a mixture of SAVE % become master of drawing and earn $20 to $75 weekly. plain and code language the maximum It is easy to make your own at LEARN AT HOME -Good paying positions open everywhere. Intense activity in manufacturing, length of a chargeable word is set at ten home with the aid of these 4 up- railroading, building, etc., calls for more draftsmen. letters or characters. to -date books that you can under- Shipped on 7 Days' FREE Trial In dispatches written in a mixture of stand. Each has over 72 pages plain, code and cipher languages, the pas- and over 60 illustrations, 3 CYCLOPEDIA OF DRAWING sages in both plain .and code language are color cover, size 5 s 7 inches. 4 Volumes. 1650 Pages. Thousands of Illustrations. charged as code language, and the passages HOME MADE ELECTRICAL APPARATUS Bound in genuine American morocco. Pages 534 x8% In Three Parts inches. Covers all branches of Drafting- Archi- in cipher language are charged at cipher VOL. I- Contains working drawings and directions tecture, Electrical, Structural Steel Sheet Metal, rate. for making all sorts of Static Machines, Static etc. Teaches pen -and -ink rendering, lettering, free- Apparatus, Rome-made Batteries, Storage Cells, hand, perspective, shades and ahadowa, working In dispatches written in plain language Transformers, Rectifiers, eta shop drawings, machine design, etc.. etc. and cipher language, the passages in plain VOL. 2- Contains working drawings and directions Only you for all sorts of Voltmeters, Ammeters, Galvano- 50c a Week books. Cop nh ffer, language are counted as plain language, meters, Switches, Rheostats, Telegraph Keys, Sound- good only within borders of U. S. and Canada. ers, Telephones, Shocking Coils, Spark Coils, Ex- Free Membership In This Society. -A Consulting and the passages in cipher language are periments, etc. Membership given free with each set -worth $12.00. counted as cipher language. VOL. 3- Contains working drawings and directions for making all sorts of Dynamos, Motors, Electric AMERICAN TECHNICAL SOCIETY A sender may prepay a reply. To do so Engines, Miniature Lighting Plants, Wireless Tele- Dept. D -254 Chicago he must before address graph Apparatus, Teals Coils, Wireless Telephone, write the of the Electroplating, Experiments, etc. message the indication of prepayment, as HOME -MADE TOY MOTORS -Gives complete de- AMERICAN tails with working drawings for making 12 simple TECHNICAL well as the number of words prepaid for but operative electric motors. Several built from SOCIETY the answer; thus R.P. 10 (to) Lathrop, sheet 'tin," Others with castings. Dept. D -254 Paris, etc., expression "R.P. 10" being e ch a Chicago, U. S. A. the C postpaid THREE Please send Cyclopedia of counted and charged for as one word. 35 1.00 Drawing for 7 days' examina- GET THEM NOW tion, shipping charges collect. RADIOGRAMS. I will send $2.80 within 7 days Radiograms are messages which must be PRICE MAY ADVANCE ANY DAY and $2 a month until $14.80 is paid, or notify you and hold books transmitted thru the medium of the ether COLE & MORGAN, Inc. Publishers subject to your order. Title not to pass Dept. 124, 19 Park Place, New York until fully paid. by means of radiated electro- magnetic Name waves and may originate on board a vessel Address at sea to a distant inland point or vice Reference versa. There has also been recently in- Electric Alarm Clock and Bank augurated a radio service between the FIVE DISTINCT USES United States and various European points, SERVES whereby radiograms may be sent to and Electric Alarm, Electric Call Bell, Electric from England, Norway and other nations Lamp, Savings Bank, and Safety Deposit in the same manner as cablegrams. Guaranteed Accurate Timekeeper. Alarm Rings In general, the system of counting the Until You Get Up and Stop It words in a radiogram is identically the 1HI®W TO same as that employed in cablegrams ; in other words, the "cable count." Names of SE1LLY® iLJ ships are counted as one word each, irre- R spective of the number of letters in the address. In the case of two or more ships REAL of the same name (which is not an uncogi- mon occurrence) the line controlling the ESTATE vessel should be included in the address, as in the following manner: "Smith, Ward - line Steamer New York, via Cape May Radio." Radiograms originating on land and destined for vessels at sea are sent by land radio wire to the coastal station nearest It1yhy tl tba CKI ot Ne Cloet at anr uav ef Ne are am rM.. Yl rae ret pp edomp e. slmplr we .Al e.l n to the point or zone within sending and re- ..ar la.b., I tn. eloea. t tñe .aa,. rnom er mw+. b. e a..arl . e Mm°ÿu< <.CI bell a. de.4.d.ï Au oll E.II In d

Build This $150 PHONOGRAPH Out of a Dry Goods Box! WE MAKE IT EASY The cut at the left, shows a beautiful Phonograph, which you can build out of a common dry goods box, similar to the one illustrated below. This machine is handsome in design and will be an ornament to any home. Its lines are simple and pure Colonial. All who have heard it, say it has A Tone of Surpassing Beauty Equal to Any $250 Machine rich, sonorous, like a violincello, due in part to the shape of the sound chamber, an exclusive feature in all our This Machine was Built from a Dry Goods machines. It plays all records, giving them a new beauty Box, similar to the One Shown Below. which has been a delight to all who have heard them. All are astonished at the great volume as well as the superior quality of the tone, and a superior tone is what all phonographs are judged by, and what all makers strive for. We have made it an easy matter to build a phonograph out of ordinary material with the aid of our Simplified Plans and Instructions which are so easy to follow, as they are completely worked out in every detail. Any person who has a few, ordinary tools -saw, hammer, plane, screw driver, and some sand paper -can now build a phonograph with our help, and with no chance for failure. This is amply proved when you look again at the machine illustrated above. You, too, can build one like it out of a dry goods box with the aid of our plans, because, what one man did, you can do. You will be amazed how easy it is and how fascinating when you get started, also how cheap. We Cut the Costs on Phonographs We have not only made it easy, but cheap to build a phonograph under our plan. We furnish all mechanical equipment -double spring motor, (plays three 10 -inch records), 12 -inch turn table, speed regulator, tone arm, (plays all records), continuous cover hinge, cover support, four butt hinges, four socket casters, one modulating rod, four door-friction catches, four door knobs, with simplified building instructions, and three 10 -inch records, -all for $20. A machine of similar quality, with this equipment, would be priced at $150. in any store! And there is another angle to the proposition that will interest you. As soon as your friends hear your machine, they are going to want one just like it, because of its beauty of design and wonderful tone. In this way it will not be long before you find yourself with orders ahead, and in an incredibly short time will be started-well started-in The Business of Building Phonographs and there is no business on earth that pays better. People want a phonograph in the home, because of the enjoyment it brings to all. You know this of course. Why don't you decide right now to build your first machine? The business end of the proposition will quickly follow. It will only cost you a two -cent stamp to get full details. The coupon will bring them promptly. Agents Are Making Money MODERN PHONOGRAPH SUPPLY CO. under our plan and we want to hear from more men who are ambitious and are 243 Springer Building, 313 S. Clinton St. looking for the Big Opportunity to get into business for themselves on a small capital, and be independent for life. Write today for full details. Use the Chicago, Ill. coupon. Take advantage of the wonderful times ahead. 1920 will be America's Send me banner year. Get your share of this prosperity. Let us help you. Exclusive full details of your Build Your Own Phono- territory allowed. graph proposition, and the Big Opportunity Agents. for MODERN PHONOGRAPH SUPPLY CO. Name 243 Springer Bldg., 313 S. Clinton Street, Chicago, Ill. Address

City or Town State You benefit by mentioning the "Electrical Experimenter." when writing to advertisers. 1302 ELECTRICAL EXPERIMENTER April, 1920

Elena Mars ! THE By H. WINFIELD SECOR CONQUEST (Continued from page 1250) OF well, and it is not 'formed of any earthly combinations or codic conjugation with POVERTY which you are familiar. Can you imagine what your first effort would be towards ELECTRIC á By HELEN WILLMANS POST solving this problem? Talking Machine For the moment we may even consider Never. Wind It The most popular book in that you have at your disposal even the Stops itself when through - 1:- the range of Mental Science interplanetary wireless telephone, but of playing. Fits any cabinet. ¡. _. , course in its infancy, so far as communica- Electro Mechanical Parts Co. _ - (New Life and Self Help). It 160 N. Wells St., Chicago, III. the mind, tion with the Martians is concerned. brings freedom. to Is it not a most interesting philosophical and through the mind to the what you conundrum to try and think just RICHARDSON'S body. would do in this case? Would you try to POLYPHASE SLIDE RULE This book is wonderful. The talk to the Martian and encourage him in the English tongue in your endeavor to find demand has been so great that ossm rygily.r.t.,,ewwww..t :.,,, id . word "gouka" meant? Or per- now we offer a cheap edition out what the haps, if you are a linguist of high attain- has the regular A, B, C, and D Scales; also a CI or that we sell at $1.00 a copy for ment, you might possibly try talking to him Polyphase Scale, Logarithm. Sine and Tangent Scales. All graduations are printed on white coated steel from engine a short time only. in several different tongues, of which there divided plates. These Scales are accurate and will retain the last count, 420 different species their accuracy indefinitely. They are not affected by acids. were at alkalies, water or grease. Length of rule 10 ". A 100 page on the face of the earth. Instruction Book which teaches all there is to know about slide rules, Is sent with each order. Dr. B. Lust's Publishing House But we won't keep you guessing any Price of the Richardson's Polyphase Slide Rule, in case with 100 page Instruction Book $2.00. Dept. E, 110 EAST 41st ST. longer, because we know you will undoubt- An ideal Slide Rule. It is low priced and an equal to edly tire of this reasoning, and in the next any other rule in appearance, accuracy and durability. NEW YORK Be convinced. Your money will be promptly refunded if issue we shall tell you what this (supposed) you are not satisfied. Send for our 40 page oo^'CITY__AAcc oo^^^^aa'' means. catalogue of supplies. It describes Martian word rules ranging from 50e to $10. each. Instructions in Looking at Fig. 4 once more, take a piece Logarithms and Trigonometry free with every catalogue. of paper and cover up the little animal at GILSON SLIDE RULE CO. NILES, MICH. the left of the word r -a -t, and just imagine what a quandary you would be in upon SEND NO MONEY your first sight of the word rat, even tho by long and patient study you had learned STAUNCH the outlines of the letters and knew that TOOL Chest economy means a I'nion Tool Chest -the WE TRUST YOU cheat of stauncher construction for stauncher service. We dollars they constituted elemental parts of a cer- Built of solid oak top and bottom rabbited in and th ofvaluableupCreeentq suçh aaW frame joints lock- cornered, Tool Sterling Si leer Initial W Ater Sets Air Rifee tain language, -it matters not which one. not dove -tailed. Union Guns. Moving Picture Machines Musical Chests outlast the tools they contain. Bangs, knocks, Instruments, Cameras. Printing Presses. Remember, the Martian could not talk to jolts, falls, bad weather do not hurt your tools when Puzzles, o n Novelties,ovelieGamTrckT you, even tho he had a wireless telephone you keep them safe and se- Stampsiis. Household s adLabor Saying Devices, cure in a Union Tool Chest. and All you have name transmitter which reached the earth, be- 10 Styles and Sizes. cou. witto t.y charge, extra large De Luxe colored pictures, to eel l cause he does not know your language. And Write for Catalog, prices stage each When soled, sená a the 185.001 and name of nearest deal- how are you going to ask the Martian in a er and guarantee. If no t- letlon tolthevob oof 8!4d.0Ó from our won- stealer for derful 300 page prremium catsing Remain. language which you know nothing about near you, write ber, set t good as atpremium for special offer. the pictures and ndina o r You the word means, and what is still áo not lime r one red for them. what B ocon:Mai tae sale of our soot% you can earn know pro- Union Tool Co., Inc. bicycle stem . worse, how would you the proper Chest IWanv ,':.annd rneon ioi. havc,, mn.et ru ., de h%.e nunciation of the word? The answer is, 36 Mill Street á.. ü. n rdfan. .nl tnd.11a. ion n Rochester, N. Y. ca have (our rh cc on11.0 ,th or a::,..1'4! you could not! ,ono :of me Y. uine.: ::I ""'d. wnb!sené that after you had been ... e aó tt n %t oncrem aenná .er ecl b b But supposing 1St euoc miumsfp l M u r b a dlr m len looking at this word for a long, long time, u JOHNSON SMITH At CO.. that suddenly one night an outline appeared OM. ES, 3224 N. Heleted St., CHICAGO alongside of it of an animal that looked like a rat! In other words, remove your piece Latest Book On of paper from over this part of the illus- SWALLOWS RIFLE NOISE tration on the left of Fig. 4 and lo and be- SELENIUM CELLS A wonderful invention - hold! you at once perceive that R -A -T Their Construction, Care and Use and a wonderful experience equals a rat. All your difficulties have been By F. W. BENSON to shoot without noise. swept away instantly. 73 pages, 15 diagrams and 3 halftone page inches. Cloth. Equip your 22 rifle with a And so it begins to look as if the only plates, 7% x 5'/4 logical method by which to start a commu- PRICE $1.50 nication with the Martians in either direc- Uses of Selenium tion is by means of words and pictures. Measuring Light - Transmitting Speech YwAmSi through the Telephone-Automatic Con- $0.00 from dealer or factory, complete with coup - This method is not entirely new, for sev- line. Attach it yourself. Send 6e for descriptive eral of our foremost astronomers have trol of Buoys, Street Lights and Illum- catalog and booklet Signs Control of of astonishing experi- made this suggestion; but in the latest out- inated Advertising - ence of Silencer users. from our radio and other communica- Ships and Boats at a Distance - Most burst Efficient Burglar Alarms, etc., etc. MaximSilencer Co. tion experts, who are talking of sending Av. flash -light signals to Mars, or, in SPON & CHAMBERLAIN 89 Homestead radio or 120 G Liberty Street, New York HARTFORD. CONN. other words, dots and dashes of the Morse code, forming letters of a language which we know,-the homely philosophy and sim- PROSPECTIVE STUDENTS plicity of the kindergarten rule have been Send To -day for the- Cr N will give you your N.D. degree in entirely forgotten, it seems! Ba two years, day and night classes. This Institution teaches Electrical Therapeutics. Picture yourself standing opposite a man Electrical Worker's Friend Static, High Frequency, Violet Ray, Galvanic Cur- Orthopaedics, Chiro- before and whose of 66 motor @@ rent, . X -Ray, Osteopathy, whom you never saw An electrical book as embodied under the Trip- instruc- practic, .Psychology, Tho no similarity whatever to drawings with complete P licity of Sciences known as Natureopathy. language bears Lions for rewinding and reconnect- by means of a semaphore fng A.C. motors. Special at sicians. quOurieperienced faculty of fourteen prac- yours, and that tical physicians will guide you surely and care- by a wireless instrument or perhaps a Or write for full particulars of this valuable book fully to attain success. Earn while you learn if or branch schools dots SMITH & SMITH PUBLISHING CO. you so desire. Graduates of single telegraph sounder, he starts shooting Lowrie N. S., Pittsburgh, Pa. who are here now say that the Blumer System is Dept. B. 1524 St., the most wonderful drugless healing system in ex- and dashes at you! Suppose the dots and istence. Write today for our catalogue. Start right. Address Executive Secretary, dashes correspond to letters in his language. stretch of the imagination BLANK CARTRIDGE BLUMER COLLEGE of NATUREOPATHY Can you by any Si to inter- PISTOL P ;pfd ONLY 97 Ann St., Dept. H., Hartford, Conn. conceive as to how you are going and dashes and finally as- 7 inches long, real revolver style. For 15 cents postage will bring to you "The Scientific pret these dots protection and sport, every man, woman egad Publicity Dept. of the at? boy should have one. Order at once. Get an Natureopath." Address certain what in Sam Hill he is driving desired. above college. American flag FREE. Money refunded if (Continued on page 1304) G. P. LEWIS CO., 1402 Broadway, New York City writing to advertisers. You benefit by mentioning the "Electrical Experimenter" when April, 1920 ELECTRICAL EXPERIMENTER 1303 SKINDERVIKEN Tr ANTSMT/11 TER BITT TON MOST SENSITIVE MICROPHONE OU can easily make a highly sen- electrical experimenters the sitive detectophone by using a 1 lMONGbutton has created a sensation. Skinderviken Transmitter Button to FOR $1.00 It is not uncommon to receive unso- collect the seund waves. You can build your own out- licited letters like these: "I received transmitter but- fit without buying expensive equipment. Think of the ton today and I wish to inform you that it works great fun you would have with such an instrument! and is the best I have ever seen or heard of for the It's very simple, too, and inexpensive. price. I will certainly recommend it to my friends. You can install an outfit in your home and I wish to thank you for your good service." hear the conversation being held all over the "I have been using one of these trans- house. You can connect up different rooms of a mitter buttons, and it has proved to be worth hotel. This outfit was used by secret service more than its value in. my experimenting." operatives during the War. It is being used on Actu al size. "I received one (Transmitter Button) some the stage. time ago, and they So much for its com- are just O. K. for mercial adaptations! experimenting." "I You can procure ap- have been using one paratus of the same type. of these transmitter buttons for experi- fO1,,,s, °'N° One of the main advantages of the Skin - mental work and it certainly lives up to derviken Transmitter Button lies in its all you say for it and then some." ultra- sensitiveness. You can place it in Mr. H. Gernsback, editor of this maga- any position you like. It is the greatest zine, who is the dean of electrical experi- invention in micro-phones and has won menters, said : "In the writer's opinion, ob- recommendations from men of high stand- tained by actual elaborate tests, the Skin - ing in the scientific world. It is being derviken. Transmitter Button is probably used all over the world. You can mount the most efficient device of its kind on it most anywhere. Card board boxes, market today, due to its simplicity and stove pipes, stiff calendars and hundreds other outstanding features. Should have of other places will suggest themselves to a great future." you. The buttons cannot be seen by any The same circuit connections apply to one in the room as they are so small and all experiments, regardless of how the light. Only a small brass nut is exposed transmitter button is mounted. to the view. OHOHOCRADH MusiC Al A The Skinderviken Transmitter °ISTAHCE Full directions for connecting 1° Button operates on one or two dry up the button for use as a detecto- cells. It often happens that two phone are given in. booklet which cells produce too much current is sent with each button. and the sounds are deafening. We The only instruments needed to recommend either one fresh cell complete a detectophone outfit, in or two worn out cells.

°ISTAHT REmveL Puu=° P,, ,HE addition to a Skinder- We have the utmost faith in this transmitter button. We IIEWKIE Q Ci * Boo DAAHxSnwlmleo) v i k e n Transmitter guarantee satisfactory ,a , ca,,,, service or we will refund °i)`°` °"" ,e,, ,,,-ssw Button are a receiver, the purchase price. Boys battery, and, if de- -Young and old-send sired, an induction in a dollar bill RIGHT coil. NOW I You can't lose . If you're not satisfied, you receive your dollar Ek*rERY C14R' lSKiNOCP,ViKEN TEEEGRFPH Iter IPyH 111J140111 ÙP AA tMUeAE back. fair? Ho " B OA B :cN usioE Isn't that Lc JOHNSON SMITH & CO., Dept. E -16, 3224 N. Halsted Street, Chicago USE THIS COU

Johnson Smith & Co., Dept. E.16,3224 N. Halsted St., Chicago, Ill. Gentlemen: -Please ship at once to address below Skinderviken Transmitter Buttons for which I enclose $ Name Address City State

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1304 ELECTRICAL EXPERIMENTER April, 1920

WhatThe dye matter et s. to stamps or cola wie brleg you the Pathfinder a. weeks s trcola will Pathfiaderis an Llustrated weekly, published at the ! Nations center. for the Nation; a paper that prints Hello Mars all the news of the world and tells the truth and a truth; now ín its 5th year. (Continued froid page 1302) This paper fills the bin without emptying 15 Cants the purse; it costs but $i a year. If you want to keep posted a Will bring oa what is going on Washington has become Auto and Tractor Mechanic It is of course evident that as aforemen- in the world, at the least the W or Id 's Capita/ and Earn expeoseoltimeormouey, reading the Pathfinder is a $100 to 9400 a Month tioned, and granted that both párties have this Is your means. If like sitting in the inner Young mans are yotl You you wanta paper in your council with t hose who a Young ma inclined? average intelligence, most lilkely one can home hich Is sin- mold the world's destiny. ais Come to the Sweeney make the other understand numbers from From the care, reliable, enter a School. Learn to be i tatning, wholesome, the Pathfinder Is yours. an an expert, I teach zero to nine, so that number combinations If you would appreciate a Doper which puts a with tools not books. IIIII h¡'II!¡L;IpI could be transmitted and interpreted -but everything clearly, briefly -here it is. Send I 1 1+ Do the work teat lP. /101 to show that you might like such a a Nations 155 a that's the secret of the think of hearing for the first time or, for and we will send the Pathfinder oa a probation 13 weeks. The does not repay f, SWEENEY SYSTEM that matter, a thousand times, a string of paper,us, but we are glad to invest in new friends. IN of practical training by which 5,000 five dots and five dashes of the Morse code. Capital THE PATHFINDER. Box 976 , Waskll$tse. D. C. a soldiers were trained for U. S. Gov- the other language it might mean a ernment and over 20,060 expert In inn's Boys, Build This Car. Thin silt a mechanics. Learn in a few weeks; no previous "d" or "h" or "z" and again it might mean little car driven by gasoline motar. a experience necessary. can be built any e.a a house or a cat -boat or a three -ringed cir- n by , and are eare a FREEWrite today for illustrated free catalog 35 Miles showing hundreds of pictures men cus, for all you are concerned. pls d p r e Ìst oparsow.f . hlanan a working in new Million Dollar Trade School. eg how to build this lad's car. HOW DO WE LEARN FOREIGN "EARTHLY" per hour LEARN A TRADE LANGUAGES ? It is common to hear people say: "Why, Is Record that is easy, -when they happen to over- SCHOOL OF AUTO- TRACTOR-AVIATION hear a discussion of interplanetary lan- of this e6 SWEENEY BLDG. KANSAS CITY, wi0. is WINTER MFG. CO. guage communication,-"If this as hard Car 156 Warren Street - as it sounds," say they, "then how do you TOLEDO, OHIO. account for the fact that a Frenchman AN,EASY WAY TO readily learns German, or a German learns Dutch ?" And yet it is commonplace! Very THE "ALSOP- ALL-SPARK MAKE MONEY ?i3cialrIngbt: true, it is a common, ordinary everyday oc- will make old carbon- choked plugs fire like on a small salary. Be independent. Go in the tire re- new be installed on any four-cylinder pairing huffiness. One man says "I made $60.00 the first currence, but did you ever really stop to -can day.' Others average $200 to $600 a month. Very little car. Send for illustrated cats- capital needed. Jobs plentiful. Every motorist a pos- think about it at all, and how it takes place? loque-or remit for device on sible customer. No experience needed. We teach you. Several very important and peculiar things money back guarantee. T 7 .50 Tire Repair Outfit happen when you learn a word of a foreign ALLSPARK IGNITION CO., Nix-Ma language. Supposing you are an American 13X Water St., New York Improved Wrapped Tread Method and that you visit France, let us say. Used by Tire Manufacturers As you leave your ship and take a rail- Does sa good work as the big high -priced vulcanizing outfits. A boy road train for the great city of Paris your Built for the Owner $1185 can use it. It's the only vulcanizer attention is suddenly arrested by a large -that has Automatic Heat Control, and can't undercure or overcure a tire. electric sign erected on a tall building. Re- .Requires no watching or regulating. Simple, member, now, that you do not know a word Sturdy construction. 'FREE Book of French, and assume that all of those Low coat of up -keep a of the and operation. Can- Shop." you knew not single word - "How to Open a Tire Repair around tilever springs In rear. , 4 071. - 27 R. P. It tells how to make big money. find out Comfortable E -Z riding 1081'n.wbeel bens Don't delay. Write quick. English language. How would you hnmedlate aerveriea. Fftb apeee.e- the illuminated word meant? Dealers Wanted felyeor. IWonderf Libees. CO. what newspaper ire fv dealers' territory. WonderfulW ondar[ul opportunities. C. A. SHALER Write or wire wow. 2203 Wiscaasis Possibly, if you nodded your head in the Fourth St. Waupua, direction of the display a sufficient number THE SENECA MOTORCAR CO., 43 Seneca Factory, FOSTORIA, OHIO SLIGHTLY USED of times to make the Frenchman near you eventually awaken to the fact that you -?C l3lt0113114741111VI:VP STANDARD MAKE TIRES were in doubt as to the word on the sign, BIG MONEY SAVINGS FOR.YOU Used and rebuilt motorcycles, single and twine. Size Price Size Price he would make some bodily motion to give 425 to 5110. Used bisY lee. 56.00; mu- 33x4 . (Cords) $16.00 dews, 410. A e machines guaranteed 30x31/2 12.75 you some inkling as to what the word in good working order. New bi- 5.50 34x4 cycles t Fac- . I t and motorcycles 3% 35x4 13.75 But unless you happened to live to \¡y'\ tory prices. You save dealer.' 31x4 $8.75 36x4 14.50 meant. profits.. Motorcycle and auto- 32x4 9.50 37x4 .(Cords) 25.00 be so old that you could look thru a mar- mobile twee too, end fer D rt and supplies. 3384 10.50 35x5 14.75 couple Cycle Co.. 34x4 11.75 36x5 15.00 velously high -power telescope a of catalog ;mincer Rochs.ter,N.Y. 82x4% (Cords) 15.00 37x5 15.50 thousand years from now, which would Special Brand New Tubes, Guaranteed. Martian himself, so that you flee Three sizes only. Price magnify the e can see his bodily movements, then it is 30g31/4 2.00 31x4 2.35 evident that you are going to have a merry Order now. Shipment made the same day. $1 deposit old time finding out what a similar strange required with each tire ordered. Balance C. O. D., subject if presented to you in the form of We want one exclusive repro to your examination. Specify whether you desire to have word, sentativein each locality to use clincher or straight side tire. Special cash discount of 5 illuminated letters on Mars or otherwise and sell the new Mellinger Extra -Ply, per cent. if full amount accompanies order. hand made tires. Guarantee Bond for could mean. 8000 Mlles. (No seccondu).f Shipped G. & H. TIRE & VULCANIZING CO. on the subject of how we pprov Dpnt While speaking Buy until you get our Special Direct Price,. Writs 2559 S. State St., Chicago, III. assimilate the language of another nation, M ELLINGER TIRE á RUBBER CO. it should be remembered that never do we 801 OAK ST. KANSAS CITY, MO learn a word of a strange tongue and its full meaning unless we see in some way or A STEFFEY MOTOR Charge Storage Batteries other a comparative picture of what the on your wheel will con- For Convenience or Profit words means. vert it into a practical and From any alternating current lamp socket with The American Doughboys in France successful high grade the Cambridge Rectifier. For home or garage picked up many French words: Of course use. As simple as turning on a lamp and fully motorcycle that will they did, why not? The French man or cost you less to operate than the more guaranteed. or expensive machines. Write at once and secure lowest fac- Quickly saves its cost and doubles woman would show him a bottle or cup, tory prices. Excellent opportunity for agents. Bend stamp. the life of your battery. Always saucepan or stove and utter at the same 5025 Brown St, Phila. Pa. ready when you want it. Rec- STEFFEY MFG. CO., Dept. E. tifier. Bulletin R sent On time the French word. Naturally, as he is request. an intelligent being, he will know that the Bulletin Y of Wire- particular word uttered in each case repre- Lighting Fixtures" less Telegraph Appa- Hang ratus sent for 3 cent sents the object which was shown him. Ready to stamp. So once more we see that it is in every (Direct from Manufacturers) Clapp - Eastham Co. case the simplest and the shortest method Completely wired, including glass- 131 Main SL in only logical method whereby ware. New designs. The Cambridge Bat - and fact the for No. 18 Cambridge, Mass. tery Charger, Price to teach the language of one nation to the Send catalogue other,-that is, by words and pictures simul- ERIE FIXTURE SUPPLY CO, Learn Autos and Tractors taneously, or by a similar and equally clear Sta. C Erie, Pa. Wonderful opportunities constant- illustration. ly offered trained men; we train Another very important element in inter - you thoroughly to start your own y business or make good money as language relations is the fact, particularly 7 . motor expert, driver. shop fore* in Europe, that there are a dozen and prob- Perfect,new tires,all sizes, non -skid or plain. man, etc. ably dozen different languages, so- fabric or cord. Prepaid on approval. 8000 to 5000 Graduates making several 10,000 Mlles Gu teed 4e called, which have a very large number of 30,000 Customers. Catalog Free. Agents Wanted. A \a good. Catalov Free. common generic roots, and this explains all Service Auto Equipment Corporation Cleveland,O. sea Service Bldg., /tenses City, Mo, Cleveland Automobile Schoo1,1807U4thSt_ (Continued on page 1306) . Von benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1305 t - INN t - - t - - ® t- - - t - - - - t ------Zlegtvietity taught byapractical man_ The Burgess Service is so universally suc- Hundreds of Burgess- trained men and boys have advanced to better positions by cessful, that we give positive as- means the practical electrical knowledge easily learned at home by this method. surance of per- of feet satisfaction Give a little of your spare time and you can do the same. on completing the course or money refunded. There are no strings tied to this -y o u Home Study For Beginners and Electrical Men are the judge. This home study course is based on the years of practical experience of Yorke Burgess who gives personal attention to each student. Burgess students are invariably promoted and get better salaries. Beginners get employment in electrical work after taking the course a short while. Burgess students are in demand, over 80 per cent are now engaged in electrical work. FIFTY- FIFTY EASY TO PAY FOR A simple method of learning practical electricity- supplied on easy ayments, including apparatus, instruments, materials, etc. Start any time - stop any time. Your payments cease if you are not satisfied. Send for Burgess catalog today. Gives full information without cost or obligation. YORKE BURGESS, Supt. BURGESS ELECTRICAL SCHOOL, 745 East 42nd St., Chicago, Ill. MN! 1111M1 !- NMI MEN t; - - - - - t- - - - - BURGESS BLUE BOOK I Electrical Slide Rule a practical and handy reference book for Invaluable to Any Electrical Man ELECTRICAL MEN AND STUDENTS 1 In response to many requests, Mr. Burgess has prepared a set of simple Contains over 200 CALCULATION FORMULAS and WORKED OUT PROB- concise for LEMS showing their use. DRAWINGS of ELECTRICAL MACHINERY DE- and lessons those who desire to take up the use of this VICES-INSIDE CONNECTIONS -ALTERNATING CURRENT CALCULA- practical instrument. TIONS and hundreds of every day problems are also covered. Recommended A HIGH GRADE SLIDE RULE by electrical men all over the country. Purchased by electrical concerns for their employees and customers. in a leather case, and a COMPLETE COURSE OF INSTRUCTION will be supplied at a very reasonable PRICE $1.00 1 SPECIAL COMBINATION PRICE We refund your money if the book does not meet your approval. We have selected the best rule for the purpose. The simple lessons BURGESS ENGINEERING CO., 750 East 42nd St., Chicago, In. will enable you to understand its use thoroughly. YORKE BURGESS, President Write us for full information Consulting Electrical Engineering. Power Plants, R. R. Signals, Electric Railroads, Industrial Problems a Specialty. Information furnished on electrical ' BURGESS ELECTRICAL SCHOOL subjects. Inventions perfected. 750 East 42nd St. Chicago, III. Learn Wireless OPERATORS EARN

Home ...... at $I25TO?5OMTh.....,,, J f ! We teach you wireless by mail. A thorough, practical course written by men with years of actual experience and each a U. S. Licensed First Grade Operator. You learn easily and quickly. After ten weeks to four months of studying we guarantee you a position, either at sea or in a land station, paying from $125 to $250 a month /- with board and quarters. I Start Now-Pay While Learning s You can start at once by making a small deposit and then pay the balance while learning. We give you FREE with each course, a complete set of learning instruments ti books. and all necessary text Our mail course entitles each student to a month's FREE tuition at our school in Baltimore where we have a complete ship installation. Sign and Send the Coupon for the Whole Story NOW ! Southerñ Wireless In- stitute, 423 Courtland Street, Baltimore, Md. f Send me FREE literature Wireless. Also. explain just how I can pay for your Home I Study Course while learning. I 423 -425 Courtland Street BALTIMORE, MARYLAND Address

e ¡NM I MN

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1306 ELECTRICAL EXPERIMENTER April, 1920

Big Money for Boys! IHItlill© Haas ! Delivered ó°, FLEE Your choice o? 44 styles colors and sizes in the famous line of (Continued front page 1304) "RANGER" bicycles. We pay the freight from Chicago to your town. 30 Days Free Trial o'ñe á bicycle you select, actual riding test the more clearly how it is, for example, that EASY PAYMENTS if desired. at a small advance over our Special Fac- an European comes , to America and tells tory-to-Rider cash prices. you he speaks six or eight languages, or Do not buy until you get our great new trial offer and low Factory - possibly ten. Of course he can do it, and Direct -To -Rider terms and prices. TIRESLAMPS, HORNS, pedal!, so would you as an American, if you were single wheels and repair continually thrown in with people of other parts for all makes of bicycles at Rider half usual prices. SEND NO nations as the people of Europe are inter- MONEY but write today for the mixed, some of the countries being very ntedVented big new Catalog. Boys make CYCLE COMPANY of differ- money small, and if the languages these big MEAD DepLS -101 CHICAGO ent peoples had numerous generic roots similar to your own. But when you meet ALL CH NEOAINDPWIRELESS one of these high -brows ask him if he OPERATORS USE speaks some radically different tongues, such as English, Chinese, Eskimo, Indian, Rus- o sian and Turkish, which have no similar There is a wonderful opportunity right J Q generic roots. That is another story, you .4 TORCH 3 now for boys who like electricity. Boys can bet! o who are ambitious z e1.25? and will train them- HOW A CHINAMAN LEARNS ENGLISH. < selves in spare time can step into positions 1- Fig. 5 shows an interesting case right in A PASTE just as soon as they are ready. Good sal- THAT TURNS f line with the would -be Martian conversa- 7 INTO METAL aries are offered to start splendid HEATED cc with tionalist's theories. This experiment has ac- to WHEN A match will do it. Requires no chances for rapid promotion. tually been tried out as a professor of lan- o acid or soldering iron. Joins or ó m repairs wires, metals or metalware. cs guages explained to the writer, and shows to Sold by hardware aid electrical For 28 years the International Correspond- just what he has always contended, -that, M stores, or sent by us postpaid. ence Schools have been training boys for suc- lacking a picture or verbal description to- SOLDERALL CO, Dept. 9 cess in electricity and over 200 other subjects. '129 Stoma Ave., Newark, N. J. gether with a word of a strange language, C"m;;,,$1.50 They will help you prepare right at home for or else some other visual effect, such as a a position in the line of electrical work you like motion of the body, jerking of the head, best -or in any other work that appeals to you. or pointing of the finger, etc., that it is Thousands of boys, through I. C. S. training, practically impossible for two exponents of have stepped into fine jobs, but never were two radically different languages to inter- opportunities so great as now. pret a single word of what the other is talk- Let the I. S. you. C. help Choose the work you like ing about. Learn about Aeroplanes and best in the coupon below, then mark and mail it today. how a how they fly. Build a Model This The illustration at Fig. 5 shows doesn't obligate you in the least, and it will bring a placed on Aeroplane that will fly like a you information that will start you on a successful Yankee and Chinaman were real one. With IDEAL Scale telephone line. This hap- Drawings and Building and Fly- career. This is your chance. Don't let it slip by either end of a ing Instructions you can build Mark and mail this coupon now. pened some years ago in the South Pacific exact 3 ft. duplicates of famous OUT HEME Islands, the linguist aforementioned 'planes. Send now for Draw- - -- -Tract where ings and Instructions for the was stationed at the time, and this gives a one you want to build. INTERNATIONAL CORRESPONDENCE SCHOOLS N C -4 (4t/2 ft.) Naval Curtiss Seaplane very good illustration of what we have been DeHAVILLAND Battle Plane BOX 6228, SCRANTON, PA. as two are Curtiss Military Tractor Explain, without obligating me, how I can qualify for the talking about, the languages Blerlot Monoplane position, or in the subject, before which I mark X. widely separated and have no comparisons Nieuport Monoplane C Taube Monoplane Each Postp'd ELECTRICAL ENGINEER CHEMICAL ENGINEER in common. If you think they have, go into Electrician SALESMANSHIP Catalogue of IDEAL Model Aeroplanes and Supplies, Electric Wiring ADVERTISING MAN the nearest Chinese laundry and get John 5c, if you write at once. Regular price. 10c. None Free. Electric Lighting Window Trimmer the Chinaman to wish you a "Happy New IDEAL AIRPLANE & SUPPLY COMPANY Electric Car Running Show Card Writer Making Model Aeroplanes Since 1911 Heavy Electric Traction Outdoor Sign Painter Year" or some equally plain or well- under- 159 -161 Wooster St., Cor. West Houston St. New York. Electrical Draftsman RAILROADER in his tongue. Eleatrk Maehine Designer ILLUSTRATOR stood salutation native Telegraph Expert DESIGNER ! ** ! ! -? -* Would you ever recognize it? Practical Telephony BUSINESS MANAGEMENT MECHANICAL ENGINEER Private Secretary Well, to make a long story short, the "EARN WHILE YOU LEARN" Mechanical Draftsman BOOKKEEPER "Yank" gabbled away at the telephone at Ship Draftsman Stenographer and Typist less than Machine Shop Practice Cert. Pub. Accountant his end of the line-and the "Chink" did If you are earning Toolmaker Traffic Management Gas Engineer Commercial Law likewise. They kept this up for a good many $50.00 PER WEEK CIVIL ENGINEER GOOD ENGLISH days, in fact for several months all in all, like draw -you should study Surveying and Mapping STATIONARY ENGINEER and to MINE FOREMN OR ENGR CIVIL SERVICE and the sum total of all this talking and ARCHITECT Railway Mail Clerk wasting of dry batteries, -not to mention Art Architectural Draftsman Textile O or Snot Commercial PLUMBING AND HEATING AGRICULTURE Spaniels the time which might have been enjoyably Leading Art Managers -the men Sheet Metal Worker l'eeltrvHalsing I Freesia recommend us and Automobiles Italian spent fishing on the coral shores, -was who know - Navigator NOTHING! employ our students. We will to guarantee to make you successful -Learn at Name Very few linguists have attempted home in your spare time-or in our resident T-ze-ts learn Chinese, but that language is no more school-Day or evening. Many of our students Preeent learn earn money by the sale of their drawings while Occupation difficult for a moment than trying to catalogue. Martian; for you can go to China (if you learning. Write for FREE illustrated Street ART SCHOOL and No have the price) or for that matter get ac- COMMERCIAL quainted with a Chinaman who speaks En- 708, 116 So. Michigan Avenue, Chicago, Ill. City State glish, right in New York City or your home town, and after spending several ./%0110%111.0110%%%11,1110 months in special sessions with him you will perhaps have an idea of a few ( ?) Chinese nos EASY WITH OUR HELP SAVE words. Some languages are simple and A few hours interesting work saves many dollars and gives you a machine OVER some not so simple. Ours is fairly so, and exactly to suit your ideals. We the Chinaman thinks his is first class, altho furnish motors, tone arms. case material. blue prints and full in- HALF his children spend the greater part of their structions. Plays any record. You Learn Wiring! can make fine profit building lifetime mastering its intricacies. phonographs for your friends. There are about 16,000 different signs Write Today for Our See page 1235 used in the Chinese language to indicate the Free Blue Print Oster Agents wanted for our different objects. If you want to write the ready built phonographs word house, you make a sign like this Chealeon Phonograph Co. and if you want to become a real .1a1,\ 407 Choraleoa Bldg., Elkhart, Ind. 11".%%11%11%%%% high -class Chinese college man, you /k- must learn over twice this number, NEW AUTOMATIC ADDER,t3.60 or 40,000 signs each signifying a different Makes adding easy. It's accurate. quick, durable and easily operated object. Suppose the Martians have such Capacity 8 columns. Bavea time a language ? How do we know ? We don't; brain work and errors. 65,000 pleased t. owners. Fully guaranteed. Price onderfu , new , evlce, guides your hand; corrects and even with word -pictures it would be a metal operat- your writing in few days. Big improvement in three slow job, for their objects might not be ing bands, $5.00 delivered. Agents wanted hours. No failures. Complete outline FREE, 138, 1458 Hollywood Avenue, Chicago Ill, Write C. J. Ozwent, Dept. 44, St. Louis. Mo. familiar to us. H. BASSETT & CO., Dept. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1307

WHAT THOMAS A. EDISON AND SIR OLIVER LODGE SAY. Thomas A. Edison believes, according to a recent publisht interview, that contrary to the contentions of many eminent radio scientists, the Heaviside ionization layer in the upper atmosphere of the earth would prevent earth-borne radio signals from passing out into interplanetary space -that these earth -borne radio signals would be propagated into interstellar space for hundreds of thousands of miles by means of the ether waves, and that it is possible that the Martians, if there are such beings, had received these signals, altho they might not have the slightest idea as to what they might mean. As he jocularly remarked in an interview at the recent celebration of his seventy - third birthday, and granting that the messages radiated by our powerful trans - Atlantic radio stations had reached such distances as Mars, how do we know whether they are received or impinge upon a human or a chimpanzee? It is the opinion of the writer that the stray signals to which both Dr. Marconi and Dr. Tesla refer to, as having been heard in their long - distance radio stations from time to time, are either signals from unknown distant Suppose you are stations or else they are static disturbances caused by disturbances of the electrical equilibrium of the atmosphere, or possibly being choked of the earth itself. Now that everyone in the scientific world YOUR ppponent has you about the throat age Marshall Stillman student is able to out - is taking a crack at the interplanetary com- -he is choking you I What can you do? box stronger and Lodge, the bigger opponents. Y. M. munication game, Sir Oliver Simply reach up with your hands, get C. A. physical well -known British scientist now touring directors and boxing instructors hold of his two little fingers and give them a in the United States and Canada know this. the United States, made the following sug- quick snap back. He will let go immediately. gestion : That is why they use the course, and recom- "Nonsense," said he, when asked if he Or suppose he has his arms around your mend it to others -to save time and money. thought it possible to communicate with waist, and is forcing you back and down. Marshall Stillman was Mike Donovan's other planets by wireless telegraphy. "It How can you break that hold? Simply put sparring partner -Mike Donovan, you know, your two thumbs on your opponent's eye-balls would be possible to place an immense geo- taught boxing for over thirty years at the metrical figure, say on the Sahara Desert and your other fingers on his forehead. Then, while pressing upward and inward with your New York Athletic Club. So Marshall Still- and then, if the inhabitants of Mars are of man a high order of intelligence, they may be thumbs, give your opponent's head a quick followed his methods and adapted them able to distinguish the figure and determine snap backward. He will release you at once. to home study in a very unique way. The that it had been. the work of man. Geom- (Be careful if you try this on friends.) first lessons take place before your mirror. You etry is a universal science, and it is not un- Then if you knew something about boxing, begin with things you already know - the likely that if they are of a higher order of you would be in a position to give him a breast stroke in swimming, holding out your intelligence than we that they can interpret sound thrashing. You would know how to hand for a coin, etc. Step by step Marshall the gigantic figure as an effort at communi- put the entire weight of your body behind Stillman leads you from these movements to (See illustration, Fig. 6.) cation." each smashing blow, and how to land the blow the movements in boxing which are very sim- "ILLUMINATED WORD PICTURES" FOR THE where it would hurt most. And at the same ilar to them, and before you know it, you find MARTIANS. time you would know how to guard against yourself subconsciously practicing the rudi- A writer in the Western Electric News his blows for your face, stomach or ribs. ments of boxing; the hit, guard, ducking, recently made the following suggestion Don't you see now, that no matter how big, feinting, foot work, etc. which seems almost comic' and, in fact, strong or brave you are, unless you know In addition, you receive 16 lessons in stand- tragic, when we come to figure the bill, but something about boxing and self- defense, you're ing wrestling and jiu-jitsu, and a lesson on still it has the essence of sound logic in it, not able to defend yourself like a man? daily exercise to keep when it comes down to real Earth -Martian you in good physical intercommunication. He suggests that we Wouldn't you like to learn boxing and self - condition. And to every student we send a take a large piece of ground, such as the defense quickly by a new method, at half free copy of Mike Donovan's famous book, whole State of Illinois, and install upon this cost of a single term of lessons by the old "The Science of Boxing ", specially bound for nice flat piece of ground several million method? You can. The Marshall Stillman home study. The fact that there are 175 1,000 candle -power flood lights fitted with Association teaches boxing by mail. The com- illustrations shows how complete the lessons reflectors and shutter attachments. These, plete course only costs $5, and to prove that are -yet they are compact and simple. of course, would all point sky or Martian - it is practical, we send it to you on five -day This course used to sell for $10. In getting ward, then he continues : "Choose a dark approval. You examine it, practice the les- out the Home Study Edition, we printed a night and start the flood -lights working. I sons. If you are satisfied, you keep the would suggest that a complex net -work of great quantity at one time, with the idea of shutter control circuits he hooked up with course, and send us $5; otherwise you return being able to offer it to the public for $5. But some automatic printing telegraph machines, the course. That ends the matter. What could printing is costing more every day, so we so that by shoving a piece of perforated be fairer? We couldn't do it if we were not cannot promise to maintain the $5 price in- tape thru the automatic transmitter the sure of ourselves. We know from experience definitely. If you are at all interested, mail whole set of lamps could be illuminated in that nine chances out of ten you will keep the coupon right away- remember, you don't any pattern desired the course if you give it a thorough trial. send any money, and if after five -days' trial "For instance, an outline of the United There are over 10,000 students studying it now you are not convinced that we can teach you States could be shown by the lamps (see -some of them as young as 12 years, others boxing and self- defense, you may return it. Fig. 7 herewith) and at the bottom huge they us letters, about three miles long, can spell out as old as 60-and the letters write Mail coupon to Marshall Stillman Association, the words `U- N- I -T -E -D S- T- A- T -E -S.' show that after a few weeks' study the aver- Suite E -4, 461 Fourth Ave., New York. + By the aid of their modern ultra -powerful telescopes, the scientists on Mars can or Imi - -- -Free Approval Coupon------should see at a glance what we were driv- Marshall Stillman Association, Suite E -4, No. 461 Fourth Ave., New York. You may send me on ing at, and it would not matter whether approval your Home Study Course in Self Defense, including 5 Lessons, one set of daily exercises, 3 they saw the period mark or not." rounds of shadow boxing, 8 bone -breaking holds and releases; 8 holds in standing wrestiing, and a free copy of Mike Donovan's book, "The Science of Boxing." I will return the course or remit $5 within 5 days. SPERRY PROPOSES 250.000,000,000 C. P. MARTIAN TORCH. Name I And now comes a proposal by Elmer G. Sperry, inventor of the world's most power- Address You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1308 ELECTRICAL EXPERIMENTER April, 1920

ful electric searchlight, shown in the accompanying photographs, to utilize a battery of 200 of his 1,250,000,000 C. P. searchlights in one gigantic bank and to concentrate their rays into one powerful beam of light, which it is figured that the Martians cannot miss. It is claimed that this flash of light would be visible on Mars as a star of the seventh magnitude, which is easily picked up by our telescopes. The accompanying photographs were taken on the roof of the Sperry Gyroscope Company's factory in Brooklyn, New York, and certainly shows in a very interesting manner the great power of this most powerful electric searchlight ever built. Two hundred of these searchlights would give a total candle -power for Martian signaling of 250,000,000,000-rivaling the sun itself. The fan arrangement of light beams in one of the photos was formed by an ar- 5,000 More Miles rangement of six large reflecting mirrors To which produced a very brilliant and spec- Old Tires tacular effect, as will be seen. See Figs. Stations Needed Everywhere 1 and 1 -A. You know what 4,000 to 5,000 additional tire mileage Earns $800 Month MYSTERIOUS DOTS AND DASHES MIGHT Tire is a FORM MARTIAN PICTURE. means to motorists. Haywood's Surgery This is new tire repair method that gives new life and thou- Mr. H. Gernsback has suggested that if sands of miles of additional service to tires which before would E. T. the proper interpreting be thrown in the junk pile. Think of what this means, man, as Buchmann apparatus was a money making opportunity. Think of the business that is brought into play, that the mysterious dots going begging to pay you big money if you're ready to act. He is a Tire and dashes received on the radio antenna Surgeon a t Chicago.He of the Marconi station, and also those cited /V_'K1/' Is a says: "Am by Dr. Tesla, might yield sóme very sur- earning prising results. In other words, if these Wonderful Business $800.00 per month, and were recorded, as for instance by a light Easy to Learn -No Experience Necessary confining beam controlled by a set of magnets con- Uncountable millions of tires are cut, torn, gashed and bruised, myself solely to rebuild- nected to the radio receiving apparatus an- broken down, worn out, yet with the Haywood method of tire ing of Tires by Haywood surgery all these tires, no matter how far gone, can be put back Method." tenna as Shown at Fig. 8, on a sensitized into service. Every town, every hamlet, every city needs photographic cylinder, fitted with a threaded Haywood Tire Surgeons, and it's that we are offering you - $6,500.00 Home Paid For axle or shaft, which would cause it to move a business of your own -a business that is already making John W. Blair, Toledo, longitudinally as well as rotatively, past the hundreds of 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 fluctuating light beams, that when this was $4000 a year -be independent in business for your- had just $50.00 left after unrolled from the drum there might be de- self. Let us send you all the facts. paying for my outfit. I veloped a word -picture or such as we have now have a $6,500.00 Mail Coupon-Get My Free Book home paid for, $1,000.00 shown in Fig. 8. Just put your name and address on the coupon be- in one bank, and de- Now, there is nothing startlingly novel low, send it to me by return mail, and I'll send you posits in several others." about this apparatus. As a matter of fact without obligation full particulars of this money Alow. it has been used about ten years ago for making opportunity. My Free Book explains everything. Tells how to start business with very little the transmission of pictures by radio and money. Now you can easily and quickly learn all about tires and my considerable success was had with this 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. method. The pictures can be transmitted M. HAYWOOD Write me today. The postage for stamp or post card will prove entirely either by dots or by dashes Tiro Surgery the best investment you ever made. M. HAYWOOD, President -it makes no difference which, and a min- HAYWOOD TIRE & EQUIPMENT COMPANY ute's consideration will show that with a 1.261 CAPITAL AVENUE INDIANAPOLIS, INDIANA transmission of this kind no regular se- quence of the dots or dashes is feasible or Mail To-day For /'11 Facts even possible. M. HAYWOO D, President In other words, the time element between HAYWOOD TIRE & EQUIPMENT COMPANY the succeeding dots or dashes all vary and 1261Capitol Avenue, Indianapolis, Indiana will never be alike. Due to these differences Dear Sir -Send me quick. without obligation, full particulars of Tire Surgery. I in time between succeeding signals, the ra- Name dio picture is built up. Address As Mr. Gernsback points out, were the Martians to send us such radio pictures, they would probably first pick out some astronomical fact, as for instance the planet Saturn with its rings. Alongside of this SPRING TONIC would then appear the symbol in the Mar- Your battery needs a spring tonic more surely than the human dynamo. Not brimstone and tian language whatever they might be. treacle, but some pure unadulterated electrical energy easily and economically obtained by the This is shown in our illustration, Fig. 8. use of the If the Martians were to send us pictures F -F BATTERY BOOSTER such as these, extending over a number of months, it would be very simple for any- Bantam Type 6 -6 ampere 6 volt battery $15.00 Bantam Type 12 -5 ampere 12 volt battery $20.00 one versed in deciphering foreign languages Operate from 110 to 120 volt 60 cycle A.C. Lamp Socket. to become acquainted with the Martians' I Weight 10 pounds complete with Ammeter and Battery Clips. alphabet or language, as the case might be, Include Postage and Insurance Charges with remittance on Parcel $15 Post shipment. AND UP and very soon we would master the lan- Circular No. 12 gives full information on these and larger sizes for guage without much trouble. By this method operation on A.C. or D.C. current or Farm Lighting Plants. the Martians could show us how they trans- Ask for Bulletin No. 12 mitted the messages to us, and we in turn THE FRANCE MANUFACTURING CO., Cleveland, Ohio could then follow suit and answer back by a like method. This idea was prompted by the fact that it is apparently almost impossible for us Earthians to interpret intermittent signals MODEL AIR ANE SUPPLIES such as dots and dashes or short and long flashes of light hurled toward us by another la ta end, fly Modell Aárpdene§ -° planet, into intelligible language -and as the Martians are supposed to be far more 1Send5tfor catalog l nocked -down scale intelligent and more scientifically developt models of new machines, parts, ' - -- s,and supplies. than we, it is possible that some such scheme -Ell i". as this may be eventually worked out by % 1dáung tadwey, roakigrni, ATY. ; lf$áde Mfg. C®. Bá2 ro our scientists. Many wonderful things have You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1309 happened, in the past twenty-five years and in the past one hundred years there has been a greater advance in science than in all the centuries that went before. SOME OTHER OPINIONS. Dr. James Harris Rogers, of Hyattsville, Maryland, the well -known inventor of the underground and underseas wireless, has recently announced that he is preparing to set up delicate radio receiving instruments in his laboratory capable of responding to signals up to 150,000 meters wave length. This is said to be 50,000 meters greater wave length capacity than that used at the Marconi station, where the mysterious signals have been noticed by Marconi himself and which he believes to have come from some far distant planet -such as Mars. In a recent interview Dr. Nikola Tesla had the following to say: "That the planets are inhabited is a foregone conclusion. I believe that the time has come for a seri- The ous attempt in the direction of interplanetary communication. We can begin by erecting a plant for transmitting the signals conveying the knowledge of numbers, which Things That would be the simplest truth that could be communicated to the Martians or other worlds' inhabitants, and which would be answered immediately if the planet is popu- Bigger Pay lated by a race as civilized as ours. Once the first step is successfully carried out, it would then be very easy to install more elaborate apparatus for the transmission of Will. Bring You pictures, by means of which the most intricate thoughts can be communicated." Another writer on interplanetarian com- You want these things and probably munication, believes, like Sir Oliver Lodge, many others, so why don't you double that geometric figures would be very plausible as the first stepping stone to open up and treble your pay? You can do it. With double and treble relations between the earth and the Mar- the, amount you are now earning you can go to the bank each tians, and the sponsor of a very interesting of money for a "rainy day," or theory, Mr. J. G. Carter of Clifton, Ohio, pay day and put away a sum puts forward the suggestion that the snow that can be used for profitable investments or building your flakes which fall during our winter season may even be influenced in a positive manner own home. Bigger pay would enable you to own an automo- by agencies controlled by the inhabitants of bile and to get many pleasures out of life that you cannot now other planets, such as Mars. This theory is afford. To be able go bank each pay day and steadily based on the fact that there is a very large to to the number of different geometric designs as- build up a bank account without missing it is alone worth any sumed by falling snow flakes. effort it may to increase your earning power. think In closing, we may very well take a few take Then moments to digest some remarks of an in- of the things you want that are not pictured here. Whether terested reader, Mr. Martin C. Hansen, on ever yourself. the subject of communicating with Mars. you enjoy those things depends entirely on "From some recent newspaper clippings I Every day you see men around you stepping up into better jobs and have noted the following statement : `Some wireless experts believe we shall soon be drawing bigger pay. It isn't a question of "how do they do it ?" You able to exchange wireless messages with know they have trained them- such planets as may be inhabited.' YEH! selves to handle the jobs ahead says I. And again, one article claims Venus is to be a 'younger' sister of the earth. Well! Don't Dodge a of them. The question "WHY well ! DON'T YOU DO IT ?" You want "Now, if Venus is so much younger than the things that better pay will the earth, then we must also concede its Better Job bring you so why not decide NOW race of inhabitants are also younger, both to prepare yourself for in nature and inventions. if this is true Promotion and better pay is up a better then we may have to 'feel' them for radio to you and not the boss. The job and better pay? signals for generations to come, before we big pay checks go to those who can hope to get any answer. And just as can think, act and do things Martians are supposed to have done the for themselves. Training will AMERICAN SCHOOL same thing with us for hundreds, if not OF CORRESPONDENCt thousands of years ; so will we have to keep make you a master of your on signaling the Venerians. work and place you in the job Dept. G -264, Chicago "To return to the subject of intellectual you want. There are no two Martians. If the Martians are so much it; while Please send me booklet and tell me how wiser than we by a million or more years, ways about you ignore I can ót myself for position marked X the benefits of training you are ..._High School Graduate .....Employment Manager then they have NOT tried to wireless us for ..._Western Union Courses .....Steam Engineer the past thousands or more years, as they dodging a better job. Without .....Telephone Engineer Lawyer .....Draftsman and Designer .....Business Manager certainly ought to have telescopes and other interfering with your work you ..... Automobile Engineer ..._Certified Pub. Accountard instruments to actually ascertain .....Automobile Repairman .....Accountant and Auditor what we can prepare for bigger pay right .....Airplane Mechanic ....Bookkeeper are doing along the line of inventions and ...Fire Insurance Expert .....Stenographer in your own home--after sup- ...Sanitary Engineer .....General Education Cueree mechanics, etc., and they would not be such .....Photoplay Writer .....Corn. School Branches fools as to signal us, when they would know per in some of the hours you ....Heating and Ventilating .....Electrical Engineer Engineer .....Electric Light and Power we had no instruments of any kind to re- now waste. The thousands .....Master Plumber Superintendent their signaling...... Civil Engineer Hydroelectric Engineer cord who have marked and mailed .....Structural Engineer .....Wireless Operator "If Venerians are a million years younger .....Mechanical Engineer .....Architect the Coupon to the right have .....Shop Superintendent .....Building contractor than we (if we knew this to be true), then (....Foreman's Training Course) we are certainly the most consummate fools doubled and trebled their pay. in believing we can send messages to them That is just what you can do-so Name because they are as yet the lowest cave men do as they did _ Send the Coupon. Address of the stone age."

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 I 310 ELECTRICAL EXPERIMENTER is No Light and Power A Chain Stronger Than firOallt the 5.ali1 Its Weakest Link (Continued from page 1241) and your body is no stronger than A year or so ago there was described in this journal another solar power plant and its weakest member. You can not an elaborate scheme was detailed and expect strength from a weak illustrated therein for revolving glass heating units in perfect synchronism with the chain, or health from a weak sun by means of an electric-clock regulating device, so that not only did the com- body. plete bank of solar units rotate from east to west, but also the angle of the surface For the body is like a chain-in of the units was tilted so that this surface was kept exactly at right angles with the order to be healthy it must be solar rays, which means that the surface of strong and dependable in all the glass tank or units must swing from right to left in the course of the daylight period parts. This can be accomplished from eight to ten hours, and also they must be tilted from a nearly vertical position in only by à proper system of exer- the morning- thence to a horizontal posi- cise-a system which will provide tion at noon-and then once more to an approximately vertical position again in for the regular and systematic use the evening. of the entire muscular system. In Mr. Willsie's solar power plant there is a trough arranged at the bottom of the glass heating tank into which the heated Start forging a link in the chain water at a temperature of 150 degrees or of health to -day. Send for more runs off thru a pipe into the storage tank which in insulated with layers of dry Catalog of adjustable barbells) BOTH sand. Mr. Willsie explains that the water and dumbbells will remain hot from four to ten days when stored in this tank, and here we have the Folder No. 18 describing our ( J FRE E key to a very novel principle involved in system of exercise Mr. Willsie's plant, viz., that he can run E. W. GOODMAN from "Strength" his engine and dynamo at night without Reproduced any storage batteries and obtain electric lights, etc., which he actually did at his The Milo Bar Bell Co. Arizona plant. . the plant is 5 Philadelphia, Pa. Originally, however, when Diamond & Third Sts. Dept. put into complete operation, the heated water runs from these storage tanks into the sulfur dioxid engine and boiler system, Motors, Electrical Toys as shown clearly in the diagrammatical illustration herewith. Sulfur dioxid, as is and Are Best well known, fias a low boiling point, so that Specialties it can be placed in the boiler and heated Knapp Goods have stood the test for 29 years. No detail in up, allowing the hot water to come into construction has been spared to make them the best that money contact with the boiler tubes containing can buy. The complete Knapp line includes Toy and Power the sulfur dioxid. When the sulfur dioxid Motors, Gen- to boil, you then erators and KNAPP "LEARNELECTRICS" in the boiler commences A complete Electrical Laboratory, including a very obtain the necessary sulfur dioxid steam Dynamos. Spe- valuable Instruction book by H. P. Gorman. In other cialties and A.LE.E. Covers all subjects clearly and concisely. wherewith to run the engine. Novelties that words, instead of using the fire to make amuse and in- steam in the boiler, hot water is used instruct. Fans, Rheostats, stead, which originally obtained its heat Compasses, etc. from the sun directly. And Knapp As the sulfur dioxid steam leaves the prices are al- engine cylinder it is not exhausted into the ways lowest. open air, owing to its initial high cost, but Always insist it is exhausted into a series of pipes over on Knapp water, Goods. which cold water is sprayed. This in the case of irrigation plants, such as in Arizona, MOTOR that developed by Mr. Willsie KNAPP DYNAMO is the same water that is pumped by the will electroplate. charge storage batteries, run lamps. engine (the pump being a separate ma- motors. train of cars, induction coils, in fact, the number it can be used for is unlimited. Buns on chine connected to the engine by belt or of experiments to on 110 Volts 4 to 0 Volts or can be connected run purposes, so noth- transformer. otherwise) for irrigation through ing is lost in this stage but the sulfur Price, Complete, $9.00 Price, Complete, $4.00 dioxid steam is condensed and is then re- dealer can secure them for you. DESCRIPTIVE CIRCULAR and pumped or otherwise directed back again Order to -day. Or your Specialties from 10c up mailed CATALOG of celebrated KNAPP MOTORS and Electrical into the boiler, only to be heated all over FREE on request. again by the hot water coming from the KNAPP ELECTRIC & NOVELTY CO., 523 West 51st Street, New York City sun tanks. As Mr. Willsie has pointed out, electric light was had at night at his Arizona solar YOU WANT plant, which was actually made by the rays »usT.WHAT O N LY of the sun shining during the preceding 2%2 FE ET day, a seeming paradox, were it not for the o= OVER LONG facts explained heretofore -that he has ,,pti SEA FARM 99 CENTS found it possible to cause the hot water to OR RANCH retain its quota of heat energy even for ACHROMATIC TELESCOPE MADE UPON NEW SCIENTIFIC PRINCIPLES. a time, when it is stored in such a good Telescope was never sold for this price before. Eastern Telescopes are several days at Positively of telescopes in America; we control entire production; tanks insulated with layers made by one of the largest manufacturers are nicely brass bound, with properly built measure closed 8 Inches and open over 216 feet in 4 sections. They or heat insulating lenses. Guaranteed by the maker. Every sojourner in the country or at the of dry sand, other scientifically ground and no farmer, should be without seaside resorts should certainly secure one of these instruments, materials. now is beautiful. A Telescope will aid you In taking views. Objects are one. The scenery Just by mail or express. safely packed, prepaid. for Where this may not be practicable, we brought to view with astonishing clearness Sent offer new Catalogue of Watches. etc., sent with each order. This is a grand can always have recourse to electric stor- only 99 cents. Our each telescope just as represented or money refunded. and yen should not miss it. We warrant age batteries, in which the dynamo would Send 99 cents NEW YORK. on EASTERN NOOVELTYCO., DEPT. 67, 172 E. 93d STREET, pump electric energy during the day to You benefit by mentioning the "Electrical Experimenter" when writing advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1311

certain days. Then whenever the battery became sufficiently low in its charge, the electric energy required could be drawn from the storage battery at night or at any other time. Under certain conditions it Double Your Strength! would probably not be necessary to operate the solar plant to charge the storage battery more than one day a week, as, for in- ! stance, where such a plant was installed Improve Your Health (of the proper size, of course) for, let us say, lighting a private dwelling or farm- house and outbuildings, etc. By having a Lengthen Your Life ! sufficiently large storage battery which would generate the energy required for Your Success in Life -your business, your happiness, lighting purposes for a period of one week, your social position, your future-all depend upon your this could be taken care of by charging for Health and Strength. No other two factors are so just one day complete. vitally important in making good as a man and a leader of At any rate, it is a case of getting some- men. Every Real Man feels the ever present desire for a thing for nothing, so far as spending the healthy, perfectly developed body, more nerve force, greater "coin of the realm" is concerne', and this endurance and control. And yet these very gifts are within is what most people are worried about to- reach of any one who is willing to devote a few minutes day, with the H. C. L. still soaring sky- each day to health- building, with the aid of the greatest ward. Of course, it is not something for invention of its kind in existence. nothing in a strict sense of the word, for I guarantee that my system of Condensed Exercise we are utilizing the energy of the sun's with the scientifically perfected says. The foregoing covers the doubt exprest by many people when they first hear about solar energy plants, for their invari- able and natural first question is "What about cloudy weather, and, even tho we Automatic have quite a number of sunny days, you may even have three or four cloudy days in one week ?" This is very true, but the aforementioned explanation as to charging the storage Exerciser batteries but one or two days a week, or possibly, as Mr. Willsie will more than double your constitutional and muscular strength in from two to three months, improve your health day by day and add a gratifying points out, by suitably storing the heated Resistance on abdomen increases auto- number of happy, active, productive years to your life. Hundreds of my pupils water in special storage tanks, explains matically throughout the country will gladly testify that this problem. the Automatic Exerciser will do these things. Ten minutes daily on the Automatic Exer- And, anyway, it will probably not come deer will build up a wonderful degree of fun- to pass very soon that we shall be selling damental, physical strength that will make life and installing solar electric lighting plants and work a pleasure. It will give you a Clear on the roofs of apartment houses, Brain, Powerful Heart, Massive Chest, Strong in the Lungs, Fine Back, Broad Shoulders, Well northern parts of the United States, as if Shaped Arms and Legs and a Wrist of Steel. these were as cheap as sand in the Sahara The Automatic Exerciser fortifies the entire Desert, the average city dweller would not area of the abdominal walls throughout all its layers. Its influential effect on the digestion bother with it, when he can spend $2.00 or eliminates the "special diet" question. It so a month and have the local electric light- strengthens entire organism and insures im- ing company supply all the "juice" he re- Overhead exercise munity from the many ills the "busy man" f o r straightening knows so well. It instantly relieves brain and quires without bothering his head about it. a n d strengthening body fag, making nervousness and complica- Btít it is another question when we come spine and shoulders tions a thing of the past. to consider the vast stretches of land such You quickly outgrow any "mail course "; the results are but temporary. But you cannot as those in the South and Southwestern outgrow the Automatic Exer- parts of the United States, where the fight ciser. It does not use up your for survival of plant life is seen to be de- vitality -it generates M ore pendent upon the all- important Vital Energy. Like the heart, quantity - which has a rest between each water. And here is where these solar beat, so in my system there is plants should and will find their ultimate a resting period between each goal and adoption in large quantities, for contraction of the muscles brought into play with the it is uneconomical under any consideration, Wrist and upper arm Automatic Exerciser. to attempt on a large scale an irrigation This enables you to develop of such large tracts of desert by meads of a superior physique without undergoing the strenuous and coal or oil driven plants, as these fuel com- exhaustive training which the modities are becoming more expensive each ordinary gymnasium methods year. JIOIn require. The patented mechanism of the Automatic Ebb~¡It Exerciser induces complete re- laxatlon in the nerves and TRANSMITTING ENERGY. - Massages and exec- muscles and develops great Wireless telegraphy and wireless tele- rises the small of strength and flexibility In the phony suggest the possibility of transmit- the back joints. It will cure any case of "muscle bound" condition in a short time. The ting energy by wireless waves. "Suggest" attachments for different parts of the body are hooked to the chain at any point desired. The resistance increases automatically with each pull and the numbers on the ball is right -we'll say. A Rumanian engineer, REGISTER the increase at each pull as the lever bar moves ahead one cog at a time. The resistance M. and increase is POSITIVE and UNIFORM and can be adjusted to Constantinesco, has been experimenting pounds to meet less than a pound or several in England with a method that seems the requirements of the different parts of the body. novel. WHAT OTHERS SAY He uses a tube filled with water or some "I am well pleased with the Anxo- Mr. Anton Hromatka, City Infirmary, St. such liquid, in which vibrations of the na- MATIO Exssc,sER. Before taking Louts, Mo., sends records of his results, which Records of o n e ture exercise on your machine my blood he secured with my machine and instructions month's results by Mr. of sound waves are produced at one in four months. Thomas Waring, and liver were slow and sluggish - Hamilton, end and the energy is reconstructed at the but now! what a difference -I am Strength First Second Strength Ont., Can. other end in a mechanical full of energy. of Record Record Cained form. The de- It is worth a hundred times the Thighs 754 lbs. 2,000 lbs. 1,246 lbs. Record Record tails of the apparatus are kept secret, but price I paid for it." Knees .. 759 lbs. 1,800 lbs. 1,046 lbs. 159 lbs. 411 lbs. Wichita. Kansas. EARL PINNEY. Calves and Ank- 134 lbs. 461 lbs. Constantinesco's researches have been "The Automatic Health Exerciser les 410 lbs. 892 lbs. 482 lbs. financed by the British Government, and is a wonder. It has done more for my Back .. . 508 lbs. 1,382 lbs. 874 lbs. 54 lbs. 88 lbs. health and strength in two months Shoulders a n d 41:lbs. 86 lbs. it has already been applied in the mechan- than all the exercises and apparatus Arms 356 lbs. 641 lbs. 285 lbs. 20 lbs. 54 lbs. ism that stops the discharge put together which I have tried in Neck 185 lbs. 375 lbs. 190 iba. of bullets years." MAURICE DALY, JR. Biceps 87 lbs. 280 lbs. 193 lbs. from the rapid firing Daly Billiard Academy, His fingers show an average gain in Abdomen gun of an aeroplane N. Y. City. 96 lbs. 102 each time that the blade of the propeller strength of 100'1. lbs. passes before the muzzle. This is what YOU ARE BATTLING makes it easy to fire 2,000 shots a minute FUNCTIONAL WEAKNESS IN "LIFE'S thru a propeller making between 1,000 and ANY FORM, SEND FOR BACKBONE" 2,000 revolutions a minute. (But what has which gives a full description of the Automatic Exerciser, how this got to do with the wireless transmis- Prof. ADRIAN P. SCHMIDT it works, what it will do. etc. Don't judge my machine until Suite 304-D, 1947 York City you have read thin booklet. I will send it on receipt of 4e. sion of energy? Leave it to the daily "news r Broadway,y> New ty postage. Kindly spell out your name and address plainly, technicians. "-En roa.)

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 1312 ELECTRICAL EXPERIMENTER Ellec o- ed cai Frauds By JOSEPH H. KRAUS (Continued from page 1254)

concern, in advertisements, claims that low sounds and whispers are plainly heard and altho it may be used in a few cases, the claims are misleading. The device is a small oiled silk artificial drum having a waxed silk thread attached to it. A piece of flexible rubber tube is likewise included for insertion of the "phone." The total price which the Mor- There is a Secret of the Ages. It is the open sesame which this device is $5.00, wills ley concern charge for swings wide the doors of life, gives to him who seeks and who its cost being about 25 cents. Something and possess, and enables him to whom it is similar was originally constructed in 1852 the power to enter of the Morley revealed to get what belongs to him, to realize the heart's desires, by Toynbee, altho the heads to make of life a work concern claim the invention, having secured to make the dreams of years come true, and several patents on the same. It is nothing of art and a glorious success. but an artificial drum head, which is insert- LIFE WAY PLAN. It h based upon a ed into the ear. Indications for the use of have doubtless heard of THE a com- is, that within yourself you have all the essential the same can only be determined by great scientific fact -which SECRET a most rigid examina- J,oUelements for Health, Wealth, Success and Happiness, and THE petent aurist, after just how to "swing wide the doors of life--that is, to tion. FORMULA shows you at work, earning similar nature is be- release your latent and dormant forces, and to set them Another drum of a ing sold by the Artificial Ear Drum dividends for you. a and have quiet nerves, restful Co., which is a rubber contrivance called Also, how to develop superb muscles, Ear Drum. Each end of this that function loyally and supreme mind control, with improved Medicated sleep, organs and how to gain a new is enlarged with a constricted portion in memory, and intensified power of concentration, All that is necessary is to push of the ruts, make a fresh start, raise your income, get the center. consciousness, get out the device into the ear and Zowie ! you can what belongs to you. call today for men and women to hear! There is a clamorous oppor- fill the better places, and here is an unparalleled Likewise, we have yet to see where a tunity for self romotion and a PLAN which is easy and ears has been remedied life transforming and epoch case of discharging delightful, soul inspiring, by a similar device. The Wilson ear drum making. tele- PLAN and is another of the wonderful wireless Hundreds of thousands have tried this for which great claims try it? phones for the ears have succeeded. Would you not love to and testimonials have been advanced. THE LIFE WAY The first step in demonstrating LIFE Quite different from the above devices is PLAN for yourself is to get my free book-THE claiming WAY. It explains the PLAN and is brimful of facts one even now on the market and to know. It tells you how you may called the Macaura you will be glad, the Ages," and International Notoriety, have for your very own this "Secret of blood circulator shown in Fig. 6. The in- go singing the song of abundance through life. and gave lectures So no matter what your problems may be, or what ventor organized institutes methods you have tried, send now for your copy of THE for the sake of perpetrating the sale of his It is free, and without cost or obligation on This prince of LIFE WAY. the book. blood circulator or pulsator. your part, I will promptly send you fakers, Dr. Macaura, then went so far as to Dept. 56, Los Angeles, Cal and gave two shows week- EARL WARD PEARCE, The Life Way Studios, rent auditoriums ly. His advertisements appeared the world over. Finally, after having the most marvelous advertisements, rivaling everything in splendor and imagination in various papers, announcing the discovery, and after having shifted his scene of operations thru 1 various countries, the self -styled "Doctor," Tbe 3ßreaker5 who had swindled so many thousands, was imprisoned for three years and fined $600. Atlantic City's Newest It is here called the Cirkulon, and costs over $15.00. It is a simple hand-operated, Fire -Proof Hotel vibratory device which will do none of the attractive things claimed for it, and is far less efficient Ocean Front. Unusually devices being Winter sea- than the vibratory massage during the Autumn and sold at a much cheaper rate. sons. The greatest series of ridiculous and non- sensical devices are those known as the American and European Plans gas pipe cures, among which are found Oxydonor, Oxygenor, the ocean. the Electropoise, Luxurious lobbies, spacious verandas and sun parlors overlooking Oxypathor, Oxytonor, and Oxybon. musicales and evening concerts. A palatial residence consisted of Charming afternoon garage. These wonderful discoveries for those seeking rest and recreation. Sea water baths. Fireproof a nickel plated gas pipe, beautifully finished Illustrated booklet sent on request. at both ends, with two wires running into the same. This cylinder was about 3'/z inches long and weighed about 5 ounces. At the end of the wire is a small disc THIS OPPORTUNITY TO MAKE BIG MONEY! which is attached to the wrist or ankle, or GRASP a both, by means of an elastic band and Open a TIRE REPAIRING SHOP - it is sure to be treatment. In success. Figure it out yourself. Hundreds of automobiles buckle, according to the tires that need constant repairing. filled with either nothing mean hundreds of previous general, they are You get this business and make big money. No or else a worthless compound, such as car- training necessary. We instruct you free -teach you or pulverized, everything. bon, either in stick form iron filings or perhaps coke dust. VULCANIZER The first two of the aforementioned de- VANDERPOOL possess (5 Cavity) vices were empty, altho claimed to electric ( ?) qualities. The s a day -repairs tires remarkable has capacity of $300.00 worth of work Oxygenor was claimed to oxygenate the just as they are made at the factory. Investment small fake was filled and immediate returns. Write today for full particulars blood of its victims. This and FREE TIRE REPAIRING MANUAL. with "rare and costly" materials, according to the makers (sulphur and charcoal by WM. VANDERPOOL COMPANY, Springfield, Ohio analysis). The ozone so generated traveled In answering address Dept. L directly "thru the pores" and was so pow-

When writing to advertisers. You benefit by mentioning the "Electrical Experimenter" 1313 April, 1920 ELECTRICAL EXPERIMENTER erful that a regulating cord had to be attached to the device. It cured everything from chicken -pox to epileptic fits and from measles in childhood to heart failure at old age. When placed into a tube of water it absorbed all the oxygen from it and pumped it into the blood-(at least the inventors said so). Particularly in view of the fact that water is made up of two atoms of hydrogen and one of oxygen, we are hence, questioning The Demand what the water looked like after all the oxygen had been removed! for Wireless Operators Another of these same gas pipe frauds was guaranteed to cure everything except Far Exceeds the Supply cancer and tumor, on which it had no admit effect. Of course, the makers had to The New York Wireless Institute . will make you an operator -AT that there was some trivial disease that HOME -in your spare time -quickly, easily and thoroughly. No could not be cured, as a cure -all is some- Our Home Study Course times looked upon as being a fake, but if previous training or experience required. glaring headlines state that we can cure has been prepared by Mr. L. R. Krumm, Chief Radio Inspector, everything but tumors, why, of course, Bureau of Navigation, N. Y. Radio experts able to impart their practi- that sounds more reasonable. cal and technical knowledge to YOU in an easy to understand way, These devices were sold at prices rang- will cost direct your entire Course. The graded lessons mailed you ing from $10 to $35. Their actual will The not being more than 50 cents to one dol- prove so fascinating that you will be eager for the next one. lar, and their actual value being about instruments furnished free, will make it as easy to learn the Code .00007 mills, i. e., they would bring this as learn to talk. All you will have to do, is to listen. junk. as it was to The magnetic blanket shown in (Fig. the World Over magnetic frauds which Big Salaries Travel 8) is another of the can visit all parts need not be discust at any great length as Wireless operators receive excellent A Wireless Operator magnetic devices have already been de- salaries ranging from $125 to $200 a of the world and receive fine pay and scribed. It is another method of extorting month and it is only a stepping stone maintenance at the same time. Do you the "coin" from an unsuspecting public. to better positions. There is practi- without travel? time was the earning power. prefer a steady position A wonderful seller at one cally no limit to your opportunities at the vacuum head cap which stimulated the scalp Men who but yesterday were Wireless There are many naughty hairs which the are now holding positions as numerous land stations or with the and induced the Operators the great bald headed man desired, to stop Radio Engineers, Radio Inspectors, Commercial Wireless or with a playing hide and seek and come out for Radio Salesmen at salaries up to $5000 Steamship Companies. little air. It just seemed to suck this hair a year. out. This rubber cap, connected by a hose FREE Instruments to a pump operated by foot power (or a and motor driven suction device if the person had the wherewithal to pay for the same), Text Books was clapt on the head and placed into We furnish free operation. to all students, As to the fallacy of the modus operandi. during the When a suction device is applied to any course, the won- part of the body, it causes the blood to be derful receiving drawn to that part, but at the same time and sending set causes a congestion in the superficial veins, exactly as pro- arteries, and capillaries, hence, the much duced in the il- desired results are not produced. lustration. This In addition, it may be of some slight set is not note that the hairs are only modi- value to free with our Course loaned, but fications of the skin and consist of the This wonderful Set for learning the Code furnished stu- When given to all same structure as that membrane. The Transmitter shown is the dents complet- therefore, once the root of a hair has been ing the Course. killed, and its follicle destroyed so that a celebrated Omnigraph used by shiny bald pate presents itself, it is im- several Departments of the U. S. Easy Payments possible to coax any hair from the head. and by the leading Government down will enroll Universities, Colleges, Technical A small payment Telegraph Schools throughout you. We will make the payments St®sc a ;e roattflel'c'y and anyone ambitious to the U. S. and Canada. Start the so easy that Repai1riu r' enter the fastest growing prof es- By HENRY KLAUS Omnigraph, place the phone to (Continued from page 1277) your ear and this remarkable in- sion-Wireless-may do so. will send you Wireless of an old one, altho this is not vention Send for FREE Booklet battery out Messages, the same as though you the case every time. A method of refilling Without obligating you in any way, the old frames was given in a back number were receiving them, through the "How to Become would have send for our booklet of the EXPERIMENTER, but they air, from a Wireless Station hun- an Expert Wireless Operator "-it is to be sawed off in order to get at them and you the coupon below, or postal It is better to put in dreds of miles away. When free. Mail then welded back on. or letter -but do it today. new plates and refill the old grids for use apply for your license, the U. S. in small cells which can be sold to run toys Government will test you with the for kids. model circuiting Omnigraph -the same NEW YORK WIRELESS INSTITUTE A battery with the plates short as we furnish to our will show little or no voltage, while one Omnigraph Dept. 12, 258 Broadway with the active element gone will give the students. Ask any U. S. Radio New York City normal E.M.F. but hardly no amperage. Inspector to verify this. When the plates must be taken out you P will be careful and not spoil the rest of the FREE Post -Graduate Course New York Wireless Institute N. Y. City outfit. Ordinarily it is practical only to A one month's Post- Graduate Course, Dept. 12, 268 B'way, take out one cell at a time. The connec- if you so desire, at one of the largest Send me free of charge, your booklet "How to tions between the cells must be unscrewed Schools in N. Y. City. New Become an Expert Wireless Operator," contain- else sawed in Wireless ing full particulars of your Course, including or unfastened if possible or York-the Wonder City -the largest your Free Instrument Offer. two. The pitch around the ends is melted port in the World and the Headquar- and the plates pulled out as shown in the of every leading Wireless and Name methods for ters diagram. We have used two Steamship Company. Address this, the blow torch, and moderately high pressure steam. The first is more practi- City or Town State cal because it is more convenient, handier, writing to advertisers. You benefit by mentioning the "Electrical -Experimenter" when 1316 ELECTRICAL EXPERIMENTER April, 1920

cillations of small extent about an axis perpendicular to the diafram. Light from a source, such as an arc, or, it may be, the sun, is focust by means of the first lens upon the vibrating mirror, whence it is reflected to the second lens. The latter is arranged so that the vibrating mirror is at its focus, and the beam of light is thus made parallel, ready for projecting to a distance. Close up to the first lens is placed a grid, with spacings equal and alternately opaque and transparent. A second exactly similar grid is placed close to the second lens. The incident light is thus split up into segments (indicated by the unshaded parts) and these segments are reflected GLORIA SWANSON 'WALLACE REID by Cecil B. Deiifiile Artcra t Player the small mirror to the second grid. Now when the small mirror turns through quite a small angle, the reflected segments of Hermo "Hair- Lustrrr light turn also, and the amount of light (Keeps the Hair Dressed) penetrating the second grid evidently de- FOR MEN AND WOMEN pends on the position of the vibrating mir- The hair will stay dressed after Hermo "HAIR - ror. In the diagram the position shown is LUSTR" has been applied. No more mussy, un- that in which 50 tidy looking hair. Adds a charming sheen and per cent of the maximum luster, insuring the life of the hair, as well as its is being transmitted. When the vibrating beauty. Dress it in any of the prevailing styles. mirror is set in oscillation by speech sounds and it will stay that way. Gives the hair that the light filaments soft, glossy, well groomed appearance so becom- shown on the left hand ing to the stars of the stage and screen. Guar- side of the second lens get broader and anteed harmless and greaseless. EARLE LIEDERMAN narrower and we have the fluctuating beam The Acme of Physical Perfection of light which is required. The advantages Two Sizes -50c and $1 BE A MAN OF STRENGTH AND 51 size three times the quantity of 50c size. SEND FOR POWER over Graham Bell's method are obvious. JAR TODAY. Remit in coin, money order, or U. S. stamps, What I have already done for thousands of The and we will send Hermo "HAIR -LUSTR," and the Hernio others I can do for you: I will broaden your grids need not be inordinately narrow, Booklet. "Guide to Beauty," prepaid, under plain cover, shoulders, deepen your chest, (increasing provided the distance between them and the at once. Use it five days and if not entirely satisfactory, lung power) return what Is left, and we will REFUND YOUR MONEY your enlarge your arma and vibrating mirror is considerable. The grids IN FULL. Once you use Hermo HAIR- LUSTR" you strengthen every muscle of your body. I will never be without it SEND YOUR ORDER TODAY. will fill you with vim themselves do not move at all, but we still and pep so that you BERM CO.. 542 E. 63rd St.. Dept. 104 CHICAGO will be admired for your perfect physique get the effect of a shutter which is con- and dominance of strength. trolled by the speech sounds. Send for MY NEW BOOK A photograph of the mounting of the "Muscular Development" vibrating mirror and the sound box is It tells the secret. Handsomely illustrated shown in Figure 3, and with 25 full page photographs of myself Figure 4 is a photo- and some of the world's best athletes whom graph of the whole transmitting apparatus I have trained. This valuable book and my mounted for use. In this case the sun is special offer will be sent on receipt of 10c, being used as the source of light. The sun- stamps or coin, to cover cost of wrapping light falls upon the large and mailing. Don't delay 1 Send for it now, mirror shown on while it is on your mind. the left -hand side, whence it is reflected thru the first grid EARLE E. LIEDERMAN on to the small mirror, "I believe Dept. 219 203 Broadway, New York thence again thru the second grid and the my own great projecting lens. The apparatus is mounted physical activity on the equivalent of a gun mounting and is due to my person- provided al use of Nuxated Iron ", with sights so that the beam of says Former Health Com- light may be projected in the desired di- missioner Wm. R. Kerr, of the SAVED rection, City of Chicago. "From my own and thus caused to fall upon the perience with ex- collecting lens, which Nuxated Iron I feel it Is GET OUR concentrates the light such a valuable blood and upon the selenium cell. preparation body building ''f that It ought to be used In BIG The reproduction of the speech sounds every hospital and prescribed BOOKLI. physician by every by the selenium is extraordinarily faithful. in the country." Nuxated Iron helps to make DO YOUR OWN It is easy to recognize the voice of the stronger, healthier women and sturdier men. Used by more than PLUMBING & speaker. Of course, for conversations to 3,000,000 people annually, HEATING country alone. in this be carried on, there must be two transmit- and Increases the strength NEW CUT -TO -FIT PLAN endurance of weak, run -down, ters and two receivers. nervous folks in You can install your own time, two week's complete It remains In many cases. Sat- heating or plumbing to add a few remarks con- isfaction guaranteed or system by this method as well cerning the ranges over which money refunded. At as practicalical plumber. You speech can all good drug - high costs be transmitted in this way. Everything ists. and unused materials.ate All parts come to you Cut -to -Fit depends on the brightness of the source of with plans and infor- light used, and the sizes mation furnished by our of the transmitting Engineers. Our whole- and receiving lenses or mirrors. The sun sale prices save you 1 the first cost. is the best source of light. With it, and using lenses Make 'Your Property only 6 inches in diameter for Worth 50% More transmitting and receiving, speech is read- and do the work your- ily audible 8 (eight) miles self. Home improvement away. There is is your best investment. no reason why, with larger apparatus, and O u r hot -water a n d more sensitive steam beating plants, receivers, this range should plpeless furnaces, water not be greatly extended. It is necessary, supply systems and plumbing supplies of course, to have an uninterrupted straight the most d rnmade. They line between factory. are Guaranteed satis- sender and receiver. Fog, Bend Today for the also, interferes to some extent, altho, owing Handy to the fact that selenium is very sensitive Man Book to red light and this It illustrates more than 10.000 light penetrates fog different plumbing and heating better than blue, the interruption is not as fixtures at our low wholesale great as might be supposed. The Electric Safety razor makes shaving a prices. It contains information The curvature pleasure. Blade vibrating 7,200 times a minute invaluable to the property owner, of the earth will impose the ultimate limit cuts farmer, carpenter or contractor. the beard smoothly and without slightest You can tell just what your Im- of range, and for this reason telephony by pull or irritation-feels like a gentle massage. provements will cost. It explains light could Can be used with or without electric current. our plan in detail. not be a substitute for the electrical wireless telephony which is now de- All users el lha Lek -Tro Shay speak well of it We have spared no effort or ex- veloping so rapidly. But light ray tele- A barber says- "Have shaved for years and have pense in preparing this valuable never used book. To keep from phony has the considerable any shaving device near its equal." sending it advantage of A home user says- "The most shave I've broadcast to uninterested persons ever pleasing we ask a temporary complete secrecy. It is only those upon had in my life. Shaves my face closer than I deposit of used to shave, but there is no after irritation or ill 25c which will be refunded with whom you purposely shine the light who effects as I usually your first order. Send for It get from another razor.' today. will hear what you say. For this reason No. 1 Made for use from Light Socket. telephony ¡joy light over comparatively short No. 2 Made for use from Dry Battery. ranges, Write for illustrated circular describing Lek -Tro- HARDIN-LAVIN particularly between ships at sea, Shav Safety Razor fully. CO. and between hills 40 years at 4510 -20E Cottage Grove Avenue, Chicago in sunny countries on VIBRATING ELECTRIC RAZOR CO. $500,000.00 Factories Back Our Guarantee land, may in the future prove of considerable use. Dept. 122, Omaha, Nebr. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1317

This Fire Alarm No Other Typewriter Can Do This: you are not MULTIPLEX HAMMOND' I If (Continued from page 1264) Zs anttiy the eabtie type Many styles, many languages Satisfied with separates, resulting in the weight being Two types or Ianguages always In the machin$ released. This immediately lifts up the your job -- hook on the telephone and allows the pho- ri nograph to start its call, which has been , page 1235 previously inscribed on records adapted for See this purpose. The record is also fitted with a very simple mechanism which causes it to be repeated many times over and either stops its action because the motor is run down, or else that the fire has dan- RAISE HARES US gerously neared the fireproof box of the Big demand. Wonderful profits easily and apparatus, when the link outside the cabi- ,quickly made raising BELGIAN HARES in net fuses and separates ; the telephone hook backyards, sheds, cellars, attics, etc. We then drops down into its normal non -oper- furnish guaranteed class A Stock and buy all you raise at $7.00 to $12.00 a pair and ating position. In the electrical system for pay express. Valuable illustrated book and operating the announcer an idea equally contract FREE. clever 'has been utilized. Regular thermo- GENESEE VALLEY FOOD AND FUR ASSOCIATION 25 Gladstone Street, Rochester, N. Y., Dept. No. 88 stats are placed thruout the building so that a rising temperature of 130 degrees will affect the closing of their contacts. Telegraph Pictures In this way a magnetic device very similar BY ELECTRICITY to a telegraph sounder, having a tooth Complete sets of two machines of this filed in the beam, would be drawn toward marvelous equipment at ridiculously 1 low prices. Instructive, mystifying the magnets. Into. this "V "- shaped tooth The World's and useful. This picture of President so Wilson was telegraphed by these ma- or notch is fitted a two -pronged hinge chines. Will transmit pictures; maps, that it is free to drop downward when the Most Wonderful drawings and hand writing. Picture telegraphing is the coming science. circuit is closed. Write today. A steel ball is attached to the cord hold- "Writing Machine" Here's a polyglot machine that writes all lan- L LEISHMAN CO., Dept.T Wan Mat ing the weight up. This cord is now past guages from Eskimo Indian to Rata Kana Japanese. thru the opening between the prongs so There are over 365 different type -sets to choose that the ball rests nearer the hinged por- from. The type is instantly interchangeable-two Genuine Typewriter $2 different languages or type -sets are always on the Sent Postpaid Only tion, and thus very little weight is applied machine. You "Just turn the knob " -to A real typewriter that writes letters s ONE clearly' and directly to the beam of the sounder. The change language oretype. I Write business nd social letters. Do ecbool work. Learn instant the armature is drawn toward the to hitypewrite.ly guaranteed, for magnets, the pronged fork is released and Hammond onlymy $2. Every man, woman and girl should have one. drops downward, due to the slight weight A. F. LEWIS TYPEWRITER CO. upon it. Immediately the pole is free to 1400 Broadway New York slide from between the forked lever and GET WELL -BE YOUNG -GROW TALL the weight coming downward with a sud- MANY TYPEWRITERS IN ONE Arabian Nights story the Univer- den thud releases the phonograph and Sounds like an -but sity dis- hook. machine itself is very practical, very real. It is the covery raises -the telephone receiver typewriter President Wilson uses personally -the When the link on top of the box fuses, the typewriter he took with him when he visited King impor- George. tant health in- weight drops harmlessly to the bottom, re- vention of the leasing at the same time the hook which Century. Types for all purposes Itremakea and rejuvenates the human body. It produce. normal epiaoe. it had previously held suspended, causing It frees impinged and irritated nerves, corrects contracted uscles shortened ligaents,m eliminates conjestion, improve. circulation and the phonograph to stop. and for all languages d raine of the e. will increase the body's length. d THE PAN DICULATOR CO., 332 Advance Bldg., Cleveland, O. The phonograph can at any time be removed from the cabinet and used for :peeing to suit size of type pleasure purposes and no connections what- YOUR FUTURE soever are made to the telephone, except Perfect alignment depends upon the use you make of present op- for the string which is caught around the portunities. Write now for literature explaining receiver hook. autoaliat e aiwiz tv our day and evening courses in Chiropractic, the greatest science of the age. Hurry for prices Al I on one MULTIPLEX 'advance soon. The marvelous, INSTANTLY interchangeable The New York College of Chiropractic "Rabbit Contest" type feature is only one of the 16 reasons why 1416 Broadway, New York City Awards thousands of prominent men and women in all page 1269) walks of life prefer and personally use the Multiplex. (Continued from For the Mathematician, Engineer, Chemist, Astronomer, Surveyor, Navigator -there is no SIXTH HONORABLE MENTION typewriter like the Multiplex Hammond! The Multiplex does many things that no other type- TELEGRAPHY The phenomenon of the film of the rab- writer can do! bit electrified to 500,000 volts, shown on Both wire and wireless, and Station Agency taught The Mathematical Multiplex contains the charac- thoroughly and quickly, BIG WAGES NOW PAID, page 798 of Dec. 1919 issue, may be ex- ters and signs used for writing in higher and lower some of our recent graduates procuring $138.00 per month plained as follows : mathematics, and for engineering, mechanics, etc., to start. Great opportunities for advancement. Our school the oldest and largest-annual enrollment 600 students. Motion picture films are taken at about as well as for all the ordinary work that can be Endorsed by railway, telegraph, wireless and government offi- the rate of sixteen exposures per second. done on any typewriter. cials. Expenses low- chance to earn part. Catalog free. Write. Each exposure I presume lasts about 1 /100 HEART OF DODGE INSTITUTE, 22nd St., Valparaiso, Ind. THE of a second or perhaps a little more. The THE HAMMOND WHAT EVERY GIRL streamers or flashes from the rabbit do not occur at every cycle of the 200,000 cycle MAIL COUPON FOR SHOULD KNOW high frequency current. The rabbit acts as FREE BOOKLET SENT PREPAID FOR ONLY S0c a capacity and holds the charge for an in- showing the many This book is written by Margaret Sanger, languages and type the great birth control advocate and constant. When the rabbit is fully charged, sets of the Multiplex tains information never before published. the charge escapes into the air in the form -there's a type for Anyone reading this book cannot help but The duration of every profession, be benefited. It is highly endorsed by of streamers and corona. every business, every eminent physicians. Send us your order the charge was not too short to allow more at once. Don't delay. science, including than one discharge to occur during the technical signs a n d Truth Pub. Co., Dept. B. T., 1402 B'way, N. Y. time of exposure, but too fast for the eye symbols and chemical to perceive. The first five pictures of the keyboard. TAM M ERER portion of film shown were taken just be- SSend 10 cents for my remarkable fore after the full discharge, hence THE HAMMOND TYPEWRITER CO. book. How To Stop Stammering." or 589 East 69th Street New York City Kill the fear of stammering. showing the streamers leaking out. At the Re education the key. a full discharge took place Naine The Hatfield Institute, 1000, oesrhm St.. Chicago. Ill. sixth exposure, at the instant. The last two pictures were Address LearnWatchwork, Jewelrywork and exposed just at the time when the charge Please write your occupation below. A fine trade commanding a good sal- was being accumulated by the capacity of Engraving ary, and your services are always the rabbit right after a full discharge had Also an Aluminum PORTABLE Model. 11 lbs. Full in demand. Address HOROLOOICAL Department, taken place. JoHO YASUMURA. capacity. Aek for special Folder. Bradley Institute, Peoria, Ill., for our latest catalog. R. No. 1, Sumner, Wash. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1318 ELECTRICAL EXPERIMENTER April, 1920

PilaIIbts

.H[ ...E.IHEHrE.a GrrOW JUST OFF (Continued from page 1247) DESIGN- CONSTRUCTION AUDION AMPLIFYING TRANSFORMERS This outflow of water is roughly adjust- RADIO AND AUDIO FREaULHCV TVe[ THE PRESS ed by opening the stop -cock to a greater or T . s lesser extent. The finer adjustment is then Design and Construction of effected by the suitable variation of the Audion Amplifying Transformers difference of level in the two limbs of the syphon. is Radio and Audio Frequency TYPe One end connected with a flexi- .F ble india- rubber tube, which is attached to This latest and important book by Mr. Edward T. Jones, a string passing over a pulley, and fixt to late Associate Editor of Radio News, will be of great In- terest to all radio amateurs thruout the land. The trans- the adjustable wheel B, attached to the formers shown in these books have never been described in observer's table. Rotation of in print before, and have usually been considered a manufac- the wheel turer's secret. Anyone who has several vacuum tubes cannot one direction will depress this end of the afford to do without this book because it will enable him to build the necessary amplifying transformers very readily. syphon, so increasing the flow, and in the The designs are very simple and rugged, and anybody can other direction will raise it, diminishing it. make them without trouble. Mr. Jones, the author, is a practical man who is an ex- The rate of descent of the float is thus perimenter himself and knows whereof he speaks. The book regulated with the utmost nicety, till an is printed on good paper and has an attractive cover in two colors. Paper bound. Size 5 in. z 7 in. Contains many absolute, balance is obtained. The observer illustrations, diagrams and working data necessary to build the transformers. recognizes the condition of the balance 25 4 when there is no drifting of the spot of VOOLISHED eV light on the recording-drum. The adjust- THE EXPERIMENTER PUBLISHING, CO. INC. PRICE. 233 FULTON ST. NEW YORK CITY cc ing wheel is now fixt at this position of Postpaid 9 balance. If any agent should induce an acceleration of growth, the balance is dis- turbed, and the spot of light moves, say, to tw.IMIZIMISS Two Remarkable Books the right, or in a positive direction. Any TO A NE agent which induces retardation HOW TO MAKE HQW will, on the WIRELESS WIRELEaMs No. 1 -How to Make Wireless Sending Ap- PECEOG APPARATUS other hand, cause a deflection of the SEHAINC APPARATUS spot paratus. ,o, w. t of light in a negative direction. The record is made in 4 No. 2 -How to Make Wireless Receiving Ap- the usual manner S _ paratus. By 20 Radio Experts. on a revolving drum. Our figure illus- ;,li"':._, trates the complete apparatus, which en- 25< Written and published entirely for the wireless enables us to obtain a record under balanced I,I thusiast who wants to make his own radio apparata. -or by closing the stop -cock of the syphon, Only strictly modern instruments are described and also under unbalanced- conditions. The 25C the illustrations and descriptions are exceptionally 25c wheel is graduated, and the absolute value Postpaid clear and simple. POst:aid of the compensatory movement, at any position of the circular scale, can be previously calibrated, by fixing the plant mir- THE EXPERIMENTER PUBLISHING CO. ror, and observing the extent of movement Book Dept., 233 Fulton Street New York of the spot of light on the drum, due to the subsidence of the float in a given time.

RADIO TELEMEGAFONE When used with one or more stages of amplification will reproduce signals with great volume. For the small fraction of a watt output of CONNECT f iqi" your receiver that is available for the production of signals, the to your detector or MAGNAVOX TELEMEGAFONE will produce the greatest volume of sound amplifier, and «BB" With Small Horn, as Illustrated . . $75.00 to a 6 -volt battery With Large Music Master Horn 93.00

`'WRITE FOR BULLETIN No. 21020

PnnATED iw U. SA AND FOREIDNCOVNTRIES 270I -2765 EAST 14TH STREET OAKLAND, CALIFORNIA

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1319

EIlectkrl'áfyIlrcll Canal Boats and ;;8alrges Learn to Treat Disease By ROBERT G. SKERRETT (Continued from page 1262)

ble of energizing the otherwise powerless This Way boats. The latter would have the space This is a small reproduction of one of 22 mag- now occupied by boilers and engines to nificent charts all of which we want to send utilize for revenue, devoting it either to you ABSOLUTELY FREE, just to show you how the carriage of more cargo or a greater easily you can master Chiropractic and how successfully number of passengers, and would not be you can treat disease by this modern drugless healing method. These charts show the different pain and nerve areas of hampered or made dirty by frequent fuel- the body. The science of Chiropractic is based upon the well ing. The prime movers, on the other hand, known. principle that when there is bone pressure on a trunk could go direct to the coaling pockets or nerve where it leaves the spinal column there will be pain in the area it controls; and that by relieving the pressure the pain is ban- the fuel-oil tanks and, being designed pure- ished. Chiropractic teaches you how to locate nerve pressure at ly for motive purposes, grime and smoke any point along the spinal column and how to relieve it. would not entail the same property injuries. Finally, this separation of the BE A DOCTOR OF steam plant from the freight or express vessel would measurably reduce fire haz- ards and lead to the lowering of insur- CHIROPRACTIC ance rates. But probably the most conspicuous gain Advanced Science cif Spinal Adjustment would be in shortening the lay -over periods. The great profession that within the past few years has taken the longest forward strides ever known in the history of drugless That is to say, the power steamer would healing. It has called to its ranks thousands of ambitious men and be kept well -nigh women from every walk of life. Today it is calling more insistently continuously on the job; than ever because the tide has turned strongly in favor of drug- moving one ship by day and starting back less healing. Right now the demand for Doctors of Chiropractic shortly is far greater than the supply. afterwards with another during the The American University method hours of darkness. Thus a single central Learn at Home of teaching enablesyou to study by plant mail or in class and obtain a com- would be able to take care of two plate mastery of Chiropractic. in "trailer vessels" upon a twenty- In SpareP Time the shortest time consistent with four -hour thoroughness, while you hold your position. You can pay on easy schedule. Fantastic as such a project may terms. From the day you enroll your instruction will be under the personal direction of a splendid faculty of Chiropractic experts. Our appear offhand, still a little analysis shows one aim will be to make you successful. We will work whole-heartedly how thoroly rational the scheme really is. with you to advance your interests so that in a short time you, like In effect it amounts to nothing more radi- thousands of Chiropractors, can earn a good income. cal than applying afloat principles and prac- tises that have become commonplace in the $3000 to $5000 a Year operating of electrified railways and the There are many instances of Chiropractors earning from $3000 to $5000 running of multiple -unit a year. Some upwards of $10,000. Dr. M. D. Moore of Kentucky. re- trains. ports an income of $9,000 a year. Dr. L. H. Roche, New Jersey, $6,000; And now the reader will ask, what has Dr. Hanna, of Kentucky, over $6,000 yearly. The success of Chiropractors in many cases has come so quickly as to be Mr. Donnelly done both to satisfy himself almost startling. And yet, it is not to be wondered at when you consider the and to convince others that constantly increasing number of intelligent. thinking people who are now con- there are not vinced that Chiropractic is the common -sense and really scientific way to relieve insuperable obstacles in the path of put- pain and disease and who, therefore, demand the services of Chiropractors. ting his system of distributive propulsion into effect? To begin with, a little over NOW -Your Great Opportunity four years ago he built and operated his Why not qualify now for this splendid profession that offers such re- yacht, markable possibilities for making you prosperous and independent? if you the Dawn, a craft 50 feet overall of are ambitious to make money, increase your social standing and be "some- 12 feet beam and drawing close to body," our course 4 feet in Chiropractic of water when laden. By way of power will point the way. No special preli- E AMERICAN UNIVERSITY plant he installed a prime mover in the minary study re- form of a 60- horsepower gasoline engine, quired. You gradu- Manierre Bldg., Dept. 720 Chicago, III. ate with the degree Without cost or obligation send me by mail your and this he connected directly with a 40- of D. C. (Doctor of new illustrated, 72 -page book and your Free Charts kilowatt Chiropractic), receive offer. electric generator working at 450 handsome diploma, revolutions a minute. To drive the Dawn FREE, and are ready at once to open your office. he provided a 20- horsepower motor direct- offer at once. Regular value of the 22 magnificent charts is Name ly connected to the propeller shaft, and this, Get Free Charts $31.60. Many of these charts when making are handsomely lithogtaphed in life -like colors. Mail coupon 450 turns a minute, sufficed and get all the facts. We will send you our beautiful new to give the boat a speed of 9 miles an hour. illustrated book, full particulars regarding course, easyterms together with free charts offer immediately. Don't put it off Street No. or R.F.D It will be observed that the generator was -mail coupon or send your name on a postal card -today. more eac AMERICAN UNIVERSITY needed lóto energize t'hurre Manierre t e moor Bldg., Dept.720 Chicago, Ill. 1 city for the yacht's screw. State Last summer another yacht, the New Era, modeled and dimensioned like the Dawn, was constructed and equipt with a 20- horsepower motor for the little vessel's ;propulsion and arrangements were made by which the needful electricity could be sup- When Choosing Your Profession - from the Dawn to insure a speed of It Will Pay You To Investigate 1plied9 miles an hour. The conducting cable is ;led from a reel over an elevated pulley at the bow of the Dawn and thence thru the water to the stern of the New Era, where Electrical Engineering! it is linked with the latter's operating cir- The men who reap the benefits of success in this ever -developing cuit. This cable is less than an inch in and expanding field must have a thorough technical training. diameter, and trails with a very modest THE COLLEGE OF ELECTRICAL ENGINEERING pull astern of the New Era, looping easily of the School of Engineering of Milwaukee offers you an opportunity and smoothly between the boats when they to train in fully equipped laboratories, drafting rooms and modern classrooms, under the expert guidance of foremost experienced are maneuvering. engineers and technical specialists. The New Era ,is provided with a number of storage batteries from which "juice" í Bachelor of CLIP HERE Science Degree Scheel of Engineering of Milwaukee is drawn for lighting and cooking Milwaukee, Wis. service in 3 Years when the yachts are at anchor. At one Gentlemen:- Without obligation, send me catalog. time during Entrance Requirements Photo -Story book and particulars concerning your a trial run from New York '---____.---/ Moderate. But 14 High 3 -Year Electrical Engineering Course with B. S. City to Schenectady School credits are neces- Degree. and return something nary for entering the Col- went wrong with the Dawn's gasoline en- lege of Electrical Engineering. What credits you may lack !game gine, which called for the machine's stop- can be quickly secured in our Institute of Electrotechnics. Address page. However, the SPRING TERM OPENS APRIL IST City State boats went right on- Clip the Coupon NOW for catalog and full particulars. Age both of them obtaining, for the time being, Education their motive energy SCHOOL OF ENGINEERING OF MILWAUKEE SCHOOL OF ENGINEERING OF MILWAUKEE from the storage bat- 180 -373 Broadway 180.373 Broadway Milwaukee, Wis. teries of the New Era. The normally de- Milwaukee, Wis. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1320 ELECTRICAL EXPERIMENTER April, 1920

Doubts Action "The Baby,'Y Do'eHammerless Revolver BUILD A WHITE FIREFLY $2.00 me and Matt gHecti.e Weapon. M but 41/4 1 aaaaa Long. 22 Glib,e C ertridge re) TEACH YOURSELF TO FLY laawtiad. 5650 The hysiopho e World's lightest and simplegt h n w,;`,m By H. GERNSBACK. aeroplane. Designed by George Iry I "w.i, , nbileWar orinxl.awuáñr.. D. White, America's foremost .eiixr.<ä«r°::iä aeronautical engineer. Weight iw - (Continued from page 1253) 150 pounds, length 15 ft. Needs boue mho `>nn<ñuuL i AIRCRAFT CO. haves voiserndnneolUkn". WHITE 8 -12 H.P. motorcycle engine. bow the Lande and takes off at 24 .'': 'in:, does. They have not the slightest concep- Dept. 9. 418 Merchants us ó°ien k Electrical Impulses. This Scheme Opt. SO 538 S. Danboro St.,Chicage entpe Io la. orar is coons. :arlmcya. exit:.ulo.`ins ï5. win o d ..nii Works Very Well to Transmit Music. JOHNSON sMrrke A CO.. Nar rai. 5271 atS NabW Slrst. CNICASO while it will become easy for him to un- Make Your Watches, Clocks, Etc., derstand what the music or even the human in Book on Law Free bv° awNear , ra voice is like if introduced Visible by Night :i° e , to him by means . s Write today for our new 171 -page book .n: mfn a of the Physiophone. on '.The Power of Law Training." carries e wiït+óUms tT; It n/'`.`oVaiaon 6YlitedTéa N

Edited by H. GernsbacK Don't Lose Your Rights Before disclosing your invention to any- and particularly to one send for blank form "Evidence of In this Department we publish such matter as is of interest to inventors be signed and witnessed. Phases. Regular inquiries addrest to "Patent Advice' Conception" to those who are in doubt as to certain Patent of all A sample form together with printed in- cannot be answered by mail free of charge. Such inquiries are publisht here for the benefit how to work a rule not to divulge all details, in structions will show you just readers. If the idea is thought to be of importance, we make it up your evidence and establish your rights order to protect the inventor as far as it is possible to do so. before filing application for patent. As Should advice be desired by mail a nominal charge of $1.00 is made for each question. Sketches be written on. registered patent attorneys we represent and descriptions must be clear and explicit. Only one side of sheet should hundreds of inventors all over the U. S. and Canada in the advancement of inven- at a time because of the recent snow storni. I tions. Our schedule of fees will be found SPECIAL NOTICE! have personally examined the third rail slot and reasonable. The form "Evidence of Con- Of late we have received so many letters from I convinced myself that in some cases ice cov- ception" sample, instructions relating to our correspondents regarding patent advice, that ered all of them as high as one foot. It occurred obtaining of patent and schedule of fees it has been quite impossible to publish all of them. to me that it should be possible for the traction sent upon request. Ask for them, -a post Altho printed in the soonest type possible, we companies to place an electrically heated boiler card will do. cannot accommodate more than ten or twelve anon a specially designed car and then generate swers a month. At the present time we are about steam. Three jets of steam would be expelled in four months behind. Of course, if our correspond- front of the car, one for each rail and one for ents have time, no harm is done! We would the trolley slot. With this steam it seems to me however, advise that if a quicker answer is wanted, that it would be only a matter of a few hours correspondents should avail themselves of our spe- to thaw out the railroad. Of course, where the cial service, as per the notice printed at the head snow and ice was over one foot thick the progress snow 255 OURAY BLDG., of this column. of the steam car melting its way thru the D. C. in as they come be naturally slow, perhaps only a WASHINGTON. All letters are answered turn and ice would Conception" into this office, and for this reason it will be un- few feet per hour. But, the main point is that "Originators of form Evidence of derstood why it takes so long for an answer to be in a day a vast stretch would thus be melted publisht. Will correspondents please bear this in out. I would like to know why a scheme such mindf- EDtroa. as this is not practical? If so, please give me the reasons If you think it is practical, could I obtain a patent on it ?" Printing Stamp. A. It seems that we have read of a similar (No. 380) Russell Fletchie of St. Louis, Mo., scheme that had been tried before, somewhere in says as follows: the West, but we believe it was not very suc- I have an idea on which I would like to ask cessful. While it is possible to use a device of your advice. this kind, we think the main trouble lies in the T` It is a rubber stamp working like a date stamp fact that it is difficult to keep up sufficient steam now greatly in use, but instead of the numerals by means of electrical power, because the amount running from 1 to 9 -0, it has the alphabet upon of steam which would be required to do the each rotating line or rubber belt. This stamp thawing would he quite prodigious. Furthermore, could be made as wide as wished or as narrow it would not be practical just to thaw away the TO THE MAN WITH by manufacturers. Instead of stamping dates it ice and snow only where it covered slot as well would he used to stamp words (any words). as the rails, because if the snow were deep enough AN IDEA I think this would be a great deal better than the cars could not proceed unless all of the snow I offer a comprehensive, ex- the small printing outfits now sold in department and ice had been melted on the roadbed, and this perienced, efficient service for and 10e stores." probably would require too much power. This is A. This is a good idea, but is neither new nor one of the reasons why we believe the scheme his prompt, legal protection and very practical. It would be all right for some- would not prove practical. the development of his proposi- body who had a tremendous amount of time to spare, otherwise it would be impractical. Take tion. for instance, if you would wish to spell out the Patents and Citizenship. Send sketch, or model and descrip- (383) Max Kroner, Detroit, Mich., seeks our tion, for advice as to cost, search word "extraordinary." This would mean that patents, you would require thirteen bands, and the av- advice. through prior United States wish to apply for a patent in the United etc. Preliminary advice gladly fur- erage word having seven or eight letters, the I nished without charge. amount of bands to manipulate would be very States, but I am not a citizen of this country, having been born in Denmark. Can I apply for My experience and familiarity with tedious, and we do not think that people would various arts frequently enable me to wish to bother with it. a patent, and will the United States Patent Office grant me a patent if I do apply ?" accurately advise clients as to prob- A. Yes. You can apply for a patent, and the able patentability before they go to Electro- Magnetic Brake. United States Government will issue the patent to any expense. (381) Ralph E. Hast, Elkins, W. Va., submits you. You will, however, have to state of what Booklet of valuable information the following: country you are a citizen in your application. and form for properly disclosing 'A number of powerful electro- magnets are You do not have to be a citizen of the United your idea, free on request. Write placed along the under frame of the cars directly States to obtain a patent. today. above the rails, and very close to the rails. An of each RICHARD B. OWEN, Patent Lawyer automatic coupling socket is at the end Washington, car so that when the cars are coupled a circuit "Interference." 164 Owen Baileiog, D. C. is completed. The amount of current used is (384) Pierre Bordeaux of Los Angeles, Calif., 2276 -8 Woolworth Bldg., New Yak City determined by the number of cars, and is con- writes to us: trolled by a rheostatic switch within the cab of "If I applied for a patent and another man has the engine. The current is supplied by one or also applied for a patent at the same time on more generators in the engine, used in connection with storage batteries. The electro- magnets would be connected in series. "This method of breaking would prevent the 'flat wheels' resulting from the present form of 'air brake' as the wheels would continue to revolve until the train came to a standstill. "As additional cars are added to the train, more current is used when braking. This braking would also I think, be more easily controlled. "Of course the proximity of the electro- magnets to the rails would have to be determined by the average weight and speed of the cars." for A. There have been many patents taken on Before disclosing an invention, the inventor should write electro- magnetic brakes in the past, but for some our blank form "EVIDENCE ON CONCEPTION." This should be reason they have not proved very successful, as none of them have been adopted to the best of signed and witnessed and if returned to us together with model or our knowledge. It seems that electro- magnetic opinion as brakes do not stop the train very much quicker sketch and description of the invention we will give our than an ordinary brake does. It should always to its patentable nature. Electrical cases a specialty. be borne in mind that a train is heavy enough to brake itself once the ordinary brakes have been Our illustrated Guide Book, "HOW TO OBTAIN A PATENT," applied and the wheels grind along the rails. Highest References Prompt Attention Reasonable Terms Any additional tractive effort on the rails would sent Free on request. not be worth while expending extra energy. Be- sides in order to energize these electro- magnets, an extra current supply would be necessary, which VICTOR J. EVANS & CO., Patent Attorneys is not always available on all trains. Chicago Offices: Pittsburgh Offices: Philadelphia Offices: San Francisco Offices: 1114 Tacoma Bldg. 514 Empire Bldg. 135 S. Broad St. Hobart Bldg. Snow Melter. New York Offices: 1001 Woolworth Bldg. (382) Hugh Reynolds, Brooklyn, N. Y., writes MAIN OFFICES: 779 NINTH, WASHINGTON, D. C. us: "I have been very much astonished that New Name Address York was unable to run its street cars for weeks You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1322 ELECTRICAL EXPERIMENTER April, 1920

a similar device, who will get the patent? How does the Patent Office discriminate in such cases ?" f» A. This is technically termed `interference." B In other words, ren two inventors apply simultaneously for a patent as a rule the Patent for Office throws the "case out and the two inventors CAN YOU will have to revert in litigation. think of a simple, practical idea Inventors and that will fill one of the many requests We,have on file for new inventions? It may mean a fortune for you. The Nlanuf cturers Thousands of things are needed RIGHT Ihy iophoie al%Te m,10n_ Now. You* brains can help. Send today for our great new book- "Inven. (Continued from page 1320) 13T return mail FREE. tiins and Trade Marks, Their Write Protection and Exploitation" , LACEYF? L.ACEY and learn more about making the dancers. As soon as the music starts, le Dept K. Washington,D.C, money from ideas than you ever the dancers become conscious of the music knew before. It tells many and begin to dance, enjoying the dancing, TNa A BOOK OF KNOWLEDGE FOR things that are wanted, INvrNTOSStuxlgt THE INVENTOR perhaps, even more than normal Of tw A postal will do- human Based on actual experience. it is inn. beings, due to the electrifying effect of the = Shows the pitfalls to avoid and the current. As the dancers progress; the over- proper course to follow in applying head wheel keeps turning so that the wires for a patent. Contains a list of in- do not become entangled. ventions needed. There are for- As for tunes to be made in simple inven- the normal human being he can 1g anima" tions. Do not let ignorance of pat- also enjoy the physiological effect of the ent laws deprive you of rightful We help out meat& PATENTS electrical current for profits. Start right. Send for without charge, to get the principal reason The Inventor's Manual of Valuable Information the dollars out of their ADVERTISED that Faradization is healthy and invigorat- $1.50 per copy, postpaid. ideas- having facilities ing and entirely harmless. G. E. PERRY CO., PUBL. none others possess. Another one of Dept. 20 For SALE FREE our illustrations shows what can be ac- 1328 Broadway, New York Advice free. complisht along these lines for the normal Don't delay -get the In INVENTION And book at once. MANUFACTURINU tubber bond fa >air aP aog AMERICAN SUPPLEMENT. \. Contains valuable information and advice to INDUSTRIES, INC. Published for the inventors. Tells how to secure Patents. Written man with an idea. Send for free sample by prominent patent lawyer of over 20 year's 225 Patent Dept., Send model or sketch of yourin- Dopy. One year's sub - 2.1 vnsm i> I e r bu>! o n s experience. WASHINGTON, D. G ecrlption 60e. rnníyr>ed in,00m//e/', vention for opinion of its patentable nature - FREE.Write today for your free copy of this valuable book. I TALBERT & TALBERT, Patent Lawyers 4287 TALBERT BLDG., WASHINGTON, D. C.

Hand Books on Patents. Trade Marks, etc., sent free. Our 70 years of experience, efficient service, and fair dealing, assure fullest value and protection to the applicant. The Scientific American should be read by all inventors. MUNN & CO., 622 Woolworth Bldg., N. Y. Tower Bldg, Chicago, Ill. 622 F St, Washington, D.C. Hobart Bldg.. 582 Market St., San Francisco, Cal,

VEN'T YOU SOME IDEA INVENTORS` that you can't just work out? Give us the idea-we will develop it for you. Me- chanical and electrical ideas developed. Experts in model and experimental work and in perfecting inventions. Designing and building labor-saving Fig. 3. Using Two Transmitter Buttons machinery a specialty. Get in touch with us- Parallel. Note Feathering Arrangement. In we can save you money. ELK MFG. CO., INC. INVENTOR'S BULLETIN 1926 Broadway, human being. Picture a concert hall, along New York the stage of which a battery of sensitive microphones is located. The current is led Patents Promptly Procured INVENTOR'S RECORD to the primary of a large induction coil in series Send sketch or model for actual search For disclosing your idea. Simplifies with the battery. Secondary leads of U. S. Patents. Highest references. procedure. go to metallic handles hung at the back of each Personal service. Moderate fees. Write orchestra chair thruout the theatre. for Free Patent Book. As soon as the music starts, every one in the GEORGE P. KIMMEL, Patent Lawyer audience can grasp the handles, and 99 -E Loan & Trust Bldg. Washington, D. C. WILLIAM I1.MULLIGAN they will now experience the novel effect REGISTERED ATTORNEY of not only hearing the music but also feeling it in a very invigorating manner. This thing, has already _been tried out by ATENTS the writer in a small way. If you have an invention and desire to secure a It is perfectly, patent, send for our Free Guide Book. HOW TO possible to put your body in series with a GET YOUR PATENT. Tells our Terme. Methods. C. L. PARKER loud -talker telephone. Of course, the pto. Send model or sketch and description for our opinion Formerly Member Ex- mu is of its patentable nature. amining Corps. U. S. coming out of the horn will now be weak- Patent Office. ened, but if your hands are wet or moist, RANDOLPH & CO. PATE. T LAWYER PATENTS McGill Bldg. the weakening of the loud -talker music is Dept. 172 Washington, D. C. Washington, D. C. not too great. You are now enabled to Patents, Trade Marks, Copyrights, Patent Litigation hear the music as well as feel it. It will be Handbook for Inventors, "Protecting, Exploiting noted in one of the photographs that a and Selling Inventions," sent upon request. rheostat is used, which is quite necessary to reduce the current. Some phonograph Record your invention, before filing application, by records using my form "Fixing the Essential Dates of as for instance band music are so Invention," sent upon request with full informa- WILLIAM C. LINTON loud and act so powerfully upon the micro- tion. Prompt personal services by an attorney -at- law having over twelve years' actual experience. Consulting Engineer and PatentAttorney phone diafram that it is quite impossible Reasonable pre -war chargea. B. P. Fishburne. to hold onto the handles 324 McGill Bldg., Washington, D. C. "Inventor's Adviser" mailed free on re- comfortably. It quest. Gives full information as to should be noted that on somb phonograph Patents, Trade Marks and their Cost. records not all the sounds can be trans- OFFICES mitted. In Do you know every move your attorney makes? 364 University St. 919 F St., N. W. other words, very high sounds Montreal, Canada Washington, D. C. do not make themselves felt at all, and some such records as the flute or other INVENTORS musical My clients are Immediately informed of every soft instruments do not lend them- step in the prosecution of their selves well for physiological effects. Rec- applications. PATENTS Write now -P A T E N T S-Send sketch. Send sketch or model for preliminary examination. ords containing xylophone, piccolo, band Booklet free. Highest references. Best results. Prompt- music and the ones with singing voices are Office of WARNER I. CUBBERLEY, Patent Atty. ness assured. Watson E. Coleman, Patent Lawyer, 824 22 National Union Bldg., Wash. D. C. F St.. Washington, D. C. probably the best. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1323

The EIlectîáczIl Machfinfist Thz (Continued front page 1278) WO/Maker says at Fig. 3 -B. In leveling medium and large size dynamo and electric machinery, re- "Yes, I've got quite a num- course is often had to the methods shown more, probably, than at Figs. 3 -C and D. At Fig. 3 -C a leveling ber. No trammel or bar is used, and this is placed toolmakers, but quite a across the two machined surfaces on front most and rear of the motor or dynamo base. number just the same. But As these are accurately machined and in perfect alignment with the two bearings then, I ought to have a lot of of the machine, this invariably gives accurate results. However, this gives the align- 'em. I've been buying Star- ment of the machine but in one position only, and it must also be leveled in a cross- rett Tools ever since I was an wise direction by placing the leveling trammel or bar across the machined surfaces apprentice. where the field frame is secured. The scheme of leveling shown at Fig. "You know my work calls for pretty 3 -D implies a taut cord or else a piece of shaft which may be past thru the two bear- close limits, and some way or other ings of the motor frame. The frame is I've got a feeling of confidence in then leveled until the shaft shows it is at the correct point or else the frame is leveled Starrett Tools that makes it easier for until the bearings measure with equal spac- me to do good work. ing around the center cord or string. In in this case also the base must be leveled I get my first Starrett Tool? a crosswise direction, as at X, by plac- "When did ing a leveling board or bar across the two Oh, somewhere back in the 80's. In fact, it the field frame machined surfaces where have been pretty soon after the Starrett will later rest. must ¶OsS one thing that atl- SECURING MOTORS IN PLACE. factory started. There's ways impressed me. Right from the start, Small and medium -sized dynamos and motors are frequently secured in position Starrett Tools have been designed and made after they have once been aligned with the who knew machine shop 'practice shafting or other machinery which they are by men to drive, by means of lag bolts. A lag bolt You know, practical men. And somehow it is, in reality, a glorified wood screw, and in the quality of the tools," it resembles a bolt at one end and a wood shows screw at the other, this end being brought to a point so that it can be driven into wood and then turned with a monkey wrench, The L. S. STARRETT COMPANY which will cause it to thread its way into THE WORLD'S GREATEST TOOLMAKERS the wood the same as any ordinary screw. Manufacturers of Hack Saws Unexcelled At Fig. 4-A a motor is shown fastened to a wooden ceiling, It is usual to place two ATHOL, MASS. pieces of wooden joist across the feet of the motor as shown at A, and these joists are lagged to the wooden floor beams. The Accuracy, utility, and quality are built into every Starrett Tool. Write heads of the lag bolts should be counter- fur Catalog No. 21 -LE- sunk down into the wood so that the surface of the joists present a perfectly level plane. Then the motor is blocked or held in position, and the feet of same are secured to the small cross -joists by the lag bolts. It is BOYS! - BE A REGULAR MAGICIAN usually necessary to prevent splitting the Mystify your friends, give real mystery shows, - wood with large lag bolts, to drill a small you can do it easily with the hole before they are started with the hammer and then turned with the monkey Mystero Show Outfit wrench. (Only $1- Postpaid) At Fig. 4-B another method of motor in- Contains 12 new surprising tricks, used by pro- stallation is shown. The floor beams under fessional magicians. Complete illustrated in- which the motor is here secured may be of structions in every box. All the tricks will be as wood or concrete. clear as day to you, but no one else can under- Cotter pins passing thru small holes stand them. drilled thru the ends of the bolts are best Send your name and a dollar bill to used, but some motor concerns who supply UNIQUE GAME & TOY SERVICE bolts for this purpose provide self -locking 1328 Broadway New York, N. Y. nuts, or else cut spring -lock washers, which are placed behind the nuts so that when these are tightened up against the washers, the spring in the washers will exert pressure SKINDERVIKEN TRANSMITTER BUTTON against the nuts, and thus prevent them The smallest and most sensitive transmitter in the world. from being shaken or vibrated loose. Send $1.00 for button and booklet with circuit diagrams. At Fig. 4-C one scheme for mounting a motor on a concrete floor is detailed. The J. SKINDERVIKEN motor is mounted on two wood stringers Inventor and sole manufacturer made of two pieces of joist placed under 335 Broadway, New York, or 154 West Randolph St., Chicago, Ill. the feet of the motor. These joists arg countersunk for lag which are thread- WITH LITTLE EFFORT bolts, GREENAMpcalcADD r[ "AMERICAN" ed down into expansion sleeves placed in TO YOUR INCOME $V to $lo EASYY W TH Key Cutter suitable holes drilled for them in the concrete. The motor is later placed on these New Improved Green Automatic Machine wooden stringers and . secured by suitable Sharpens, Hones and Strops all kinds of safety razor blades, in one operation, IP!II from four to six blades per minute. For both Quality and Quantity, this machine size lag bolts threaded down into the is ín a class by itself. There le nothing like it on the market. Let us send you wooden joists. our tree booklet explaining everything including the "AMERICAN" Key Cutter- Cuts square, angular or round slots. (This series to be continued.) AMERICAN SHARPENING MACHINE CO. (Ise.), Dept. E E, 184 W. Washington St , CHICAGO You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1324 ELECTRICAL EXPERIMENTER April, 1920 The "Finer Work- ings" of Static ELECTRICAL- FIRES lectricity are feared by all fire fighters. By FREDERICK VON LICHTENOWI Water or ordinary chemicals (Continued from page 1275) .(_ are dangerous to However, as I have stated before, induc- use and have no tion takes place first, and that is what we have here to do with. Then follows at- effect on fire. A traction. After the short while occupied by neutralization of their "in- between" charges, the light objects retain only their induced "outer" charges (naturally opposite Fiwig-KitiErta. to those of their respective sources !) and upon separation fly, "stronger than ever" breaks electrical arcs over to these and make contact with them (See Fig. 7 -a). and extinguishes the The behavior of the balls during neutral- fire instantly. It can ization evidences in this as well as in ex- be periment No. 4, Part 1, very graphically directed into elec- what I have said in reference to their trical machinery ELBERT HUBBARD II, Editor -in -Chief ROYCROFT properties as conductors and insulators. without damage The They are a mixture of both; they are the to Greatest Book EverP tcbli shed! "Guinea pigs" of the electrostatic- research apparatus or injury worker, for they respond to anything be- longing in that sphere. to operator. 110* Whenever an object susceptible to an Write for n Zmnkan electrostatic charge is subjected to the neu- Our Agency or Distributors Plan aBiffs bigotry, slams shams and tralizing process while under the influence superstition, of an inductive (outside) force, such object THE NU -EX FIRE APPLIANCE CO. and gives the lie will invariably become charged (in this case COLUMBUS, OHIO laryngismus! ¶ The gospel ac- oppositely!) to the extent of holding the period. cording to Franklin, Jefferson, Paine, charge for a given In other words: Publishes each Lincoln, Ingersoll, Whitman, Emerson if neutralization is followed instantly by art assign- induction, a charge will be effected without ments, lessons and Elbert Hubbard. ¶ Printed Roy- the usual resort to contact (with the charg- MAGAZINE and articles on croftie in two Cartooning, colors and craftily bound ing body!). This is clearly demonstrated Designing, Illustrating, Lettering in pebble -grain flexible leather. by the action of the gold leaves of an elec- a ii d l'halk- Talking. Criticises amateurs' work. Full of Information troscope, when the latter is inductively for artists and art students. charged. The neutralizing process is the fin Outspoken Little Magazine Satisfactory rr money refunded. 20e a copy. $1 fee magic factor, which makes this possible R» yid fl NOW, Thrift Stomps Tl:rn and, to emphasize again, it must take place G. H. Lockwood, Editor, Dept. 593. Kalamazoo. Mien. "just ahead" of (almost simultaneously with!) the inductive action. This magic The ROGERS factor was made use of by the in Violet Ray, High Frequency Generator ocroft author Does not burn out. No sparking all -therefor» the successful workout of Experiments Nos. shocks are eliminated. An ideal outfit fully cr..A lively, likeable monthly pub- 3 and 4, of Part 1. guaranteed as to material and workmanship. lication edited by Elbert Hub- (To be continued) PRICE COMPLETE $25.00 With One Syrian Applicator bard II. It stands for Ameri- Send for free descriptive Booklet canism and progressiveness The Rogers Electric Laboratories Co. and speaks 2056 E. 4th Ohio the truth with force and directness. It Dept. St., Cleveland, is a magazine that will increase your Measuring Elec- Learn Watch Repairing n.tehakerm -you wann learn this progtahle tr capacity for friendship, your thinkery, tric Current with by eorree p.odence Ina few week. In your own home your ideals. by the Isrt41m, Chart Nyetem. After you complete the Icy e the course you w111 know a watch from A to Z. You will know just what th. matter Is and how to repair By C. A. BRIGGS When you graduate you will be practical BOTH, for $z.5o! .ahmol e..d myofeee and competent to All page 1276) any position. pe.Itione for our graduate.. - (Continued frone Askforourrreeamk. Use the coupon! It expiates yï, our system and term.. THE ROYCROV ERS. THE DeSELMS WATCH SCHOOL East Aurora, N. Y. the figure, by means of a potentiometer con- i2O Perry St.. ATTICA, IND. Send me AN AMERICAN BIBLE and ROYCROFT MAGAZINE (for one year) for which I enclose nected by leads to a standard resistance in- $2.50. terposed in the circuit. Name In using the device the current to be You measured is past thru the bulb nearest the Address_ , eyepiece and the current in the other bulb is varied until the observer sees that the PHYSIGIAN filament at one point disappears against A beawell -paid profession is open to ou. The field beckons to both men and women. Combined home its background, on account of the intensities study and college course. Heal without drugs. being matched. From the value of the Free catalog. International College of Drugless current past thru the bulb at the closed end, Physicians. Dept. íL44200 Grand Blvd., Chicago. as shown by the potentiometer, can be determined the current passing thru the other Send for a Complete Catalog of bulb. MASONIC BOOKS Ukulele, Hawaiian Guitar, Violin, A temporary set-up of an instrument of TENOR BANJO Mandolin, Guitar, Cornet or Banjo this character showed that very good re- Wonderful new system of teaching note mimic by mall, To Bret Jewelry and Goods [mulls In mete locality, we give $20 superb Violin, Mandolin, sults can be obtained. This accuracy is in Ukulele. Guitar. Hawaoin Guitar, Cornet. Tenor ftanjo or Beejeabso- part due to the fact that under REDDING & CO. lutela free. Very small charge for lessons only. we aearen4a sea ordinary ossso.. no charge. Complete outfit free, Write now. No entireties. circumstances a small change in the cur- Publishers and Manufacturers Dept. SLINOERLAND SCHOOL OF MUSIC, Inc. Vest, 41. CHICAGO, ILL. rents heating either filament will produce 5 200 Fifth Avenue, N. Y. a proportionally greater change in the intensity of the illumination. It was found that by this arrangement the value of an UMAKEM Airplane Workehest, containing aircraft work table with electric current could be established to mitre cutting board and length gauge. steel drill. steel within accuracy hammer. Model Maker's steel square. screwdriver, 'end- an of two parts in a thou- paper block. 10" scroll saw, together with finest quality reed and wood. I won World's First Prize for best course sand; and with further development it is ban aluminum. silk, para rubber. full in l'enmanship Under my guidance you can probable set of blueprints, directions. and all fittings for building become an expert penman. Am p Being many of my very that the accuracy could be one Se" Bleriot Model flying Monoplane. Price $10.00. etudenta as Instructor. In commercial colleges at high increased. Before use this apparatus is Other UnuleM Outfits 50o to $50. salaries. I f you w,,,h to berun.e a better penman. carne R. me. I will wend t:. óJ c,177,1,41:17 W. PRICE. Ins. an d a cope of hey of n calibrated against direct current instru- No. 2 UmakeM Building, 127 Fifth Avenue. New York C. W. Hansom, 511 Hldg.,IfunttttsClty,Ho ments. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1325 A WARNING to Manufacturers Importers Dealers Jobbers Agents Amateurs Purchasers Users of Vacuum Tubes The Marconi V. T. Patent is Basic United States Letters Patent to Fleming, No. 803,684, November 7, 1905, has been held to be valid by Judge Mayer of the United Fleming Pat. No. 803684 States District Court for the De Forest Pat. Nos. 841387-879533 Southern District of New York, and by the United States Circuit Court of Appeals for the Second Circuit. It is a basic patent and controls broadly all vacuum tubes used as detectors, amplifiers or oscillions in radio work. No one is authorized to make, sell, import or use such tubes for radio purposes, other than the owners of the patent and licensees thereunder. Any others making, selling, importing or using them alone or in combination with other devices, infringe upon the Fleming patent and are liable to a suit for injunction, damages and profits. And they will be prosecuted. THE AUDIOTRON AND THE LIBERTY VALVE ARE NOT LICENSED UNDER THE FLEMING PATENT The price of the genuine Marconi V. T. Do not take chances by making, importing, delivered is $7.00 each. The standardized selling, purchasing or using vacuum tubes socket is $1.50 additional. The standard for radio purposes not licensed under the Fleming resistance, complete, costs $1.00 and is patent. By selling, purchasing or using licensed tubes for radio purposes you made" in the following 1/2 sizes: megohm, secure protection under the Fleming patent 1 megohm, 2 megohms, 4 megohms, 6 and avoid the risk of litigation for infringe.. megohms. ment thereof. This warning is given so that the trade and public may know the facts and be governed accordingly. Send all remittances with order to COMMERCIAL DEPARTMENT

MARCONI WIRELESS TELEGRAPH CO. OF AMERICA RADIO CORPORATION OF AMERICA 235 Broadway New York

Sole Distributors for De Forest Radio 7 =lephone & Telegraph Co.

Retail Office and Exhibition Rooms, 2 Elm St.. New York 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. 1326 ELECTRICAL EXPERIMENTER April, 1920

ONLY Tanks Super-Sensitive Microphone AdvertisIln This instrument is offered $8.00 MURDOCK NUMBER 6 at an extremely low price. (Continued from page 1296) It is excellent for building your own amplifier. Can also be used No. 55 in many experiments where a our columns clean and allow only reliable sensitive microphone is required. firms to use them. And if there are any readers who have not understood the point Detectagraph, $18.00 you bring up I hope they will read this This detecting instrument of marvelous sensitivity can be used for letter carefully and write me if they feel detecting secret conversations. justly treated in any Outfit consists of Sensitive Trans- they have not been mitter, 25 -ft. Black Cord, Re- transaction. ceiver, Headband, Case and On the other hand, I do think that manu- Battery. facturers should publish the shipping weight Send for One To-day and of all articles which they do not ship pre- e Çontince Yoursaj/. paid. Many of them do, but to those who Detectagraph $18.00 don't I want to recommend it now, right THE $18.00 MICROPHO here, and I hope that all who read this will DEAF -PHONE think it over and follow the suggestion. is a super- sensitive instrument again, Mr. Reed. 'which has been. developed to meet Write the demands for a practical and Very cordially yours, efficient hearing device at an extremely low price. It is equal to any $35 instrument made and superior to most of them. The -9! outfit consists of One Super- . Sensitive Transmitter with cord Manager. connector; One Super- Sensitive Ear Piece with small black cord; One Black Single Headband; Black Case and Two Batteries. Adjusted Model "B" Horn. with No'. Some L©Il xg Distancece 20 High Grade Loud Talking Receiver, 2000 SET. $4.50 Cord Plugs and Desk Stand Base. OHM Macao Teneph ©lie Price, 512.00 Complote. 3000 OHM SET. 5.50 Tests Write To-day for Free Booklet By ROBERT F. GOWEN G. BOISSONNAULT CO. That these Murdock No. 55 (Continued from page 1281) Sets have earned a nation- 26 Cortlandt St. New York value, is only Makers of Super- Sensitive wide reputation for reporting good reception when using Microphone Apparatus due, not so much to the fact one receiving tube. that they are, without question, While continuing tests with Mr. Charles Candler at St. Mary's, Ohio, the signals the best low priced receivers and speech were picked up by Mr. R. H. G. obtainable anywhere, as it is Matthews, Chief Engineer of the Chicago 3 -INCH DIAL INDICATOR to the recognized fact that they Radio Laboratory at his Chicago Station. in opera- He reported that the speech could be heard closely approximate plainly at a distance of over 10 feet from Black tion the sensitive performance the telephone, altho the buzzer on the modu- Composition of the most expensive sets. lated wave was slightly louder. The power imput for these tests was 285 watts. with Brilliant The customary assurance of A continuance of tests with Mr. Mat- White Filled "Satisfaction or Money Back" thews during the last week in January, affords the opportunity of prov- brought in reports from Little Rock, Engraving value of Arkansas, and from Valley City, North ing the exceptional Dakota, distances of about 1200 and 1500 No. 66 Dial only 75 cents these 'phones at no risk to you. miles respectively. Mr. Clayton at Little No. 67 with Bakelite knob, $1.30 Rock reported the speech particularly For sale at all RADISCO Agencies O t h e r instruments - MUR- understandable, but Mr. Pray at Valley the speech Sent postpaid. DOCK MADE -of recognized City, North Dakota, stated that OUT, was weak, but that he was using a very NEW CATALOG JUST merit at equally reasonable ready for distribution at once. Con- in Bulle- inefficient receiving set. In February, the prices are illustrated speech was successfully heard and copied tains News, Illustrations and de- tin 19B, a copy of which will at Baudette, Minnesota, which is nearly as scriptions of all standard radio parts. be mailed on request. far away as Valley City, and many letters Sent anywhere -upon receipt of I Oc. have been received from St. Paul, St. Louis, Minneapolis, and many cities in Michigan A. H. CORWIN & CO. WM. J. MURDOCK CO. to the same effect. In the latter instances, 4 West Park St. Newark, N. J. 55 St. however, the imput was increased to 510 Carter watts and in one or two cases the tests were CHELSEA (BOSTON 50) MASS. made on a prearranged schedule. 509 Mission St. San Francisco, Calif. In practically every instance the reports were most enthusiastic as to the modula- tion or clearness of the speech. Whole What are the Wild spoken sentences were quoted and some titititi% ti %10ti even went so far as to comment upon the Waves Saying? accent of the person talking. The reports unanimously indicated that once the receiv- You can find out with "Ace" equipment. If you want to ing station found the tune of the trans- We can furnish parts for audion control panels mitted wave, there was no difficulty in hear- The become an Mr. a n d amplifiers. ing the speech clearly and loudly. panels are 3/16" for- A Candler at St. Mary's reported one night mica, grained finish, let- his steps of tering in white. Con- Expert Wireman that he could not use two trol panel includes sock- amplification as it hurt his ears. He tele- et, grid leak, grid con- Read page 1235 graphed back that the writer's voice fairly denser, rheostat, binding him. posts and formica panel. screamed at Amplifiers include the The experiments have shown that with a above and transformer, remarkably small power imput, stations etc., all ready to wire. practically half way across the United Audion Control Panel $7.50 WILCOX PANEL States can be reached even when the set One Step Amplifier 10.00 on an aerial Audion Control Panel and One Step Amplifier is operating very inefficiently on large panel $17.50 SWITCH and on wave -lengths for which it is not 20.00 "The Best" Two Step Amplifier on large panel designed. You may pay more, but you can't buy better 11/4 In. Radius Postpaid Price at eleven Complete Switch, polished brass finish.50o The tests are being continued Complete Switch, nickel plated itnish 600 o'clock nightly and the writer would be THE PRECISION EQUIPMENT C0. (inc.) Knob. turned and polished 250 Switch points, brass finish 2e pleased to hear from those who are inter- Manufacturing Engineers Switch points, nickel plated finish eo ested as to their results in receiving him 2437 Gilbert Ave., Dept. E, Cincinnati, Ohio THE WILCOX LABORATORIES, Lansing, Mich. at some distance. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1327 dNNfj `INhNMyNbfs-

a\ k\FOrk hhhMlfhil* hhs.\ A Wireless Telephone Now Possible for Every Radio Amateur! RANSMIT your messages in words instead of dots and dashes! Install a DeForest Oscillion Radiophone Transmitter as part of your set and you can do it. Nothing compli- T cated or impractical. The Type "O Transmitter shown below plugs into lamp socket. Just plug in, connect antennae and ground, push a button and talk! Voice quality superior to that over a wire; dear, distinct and continuous. Once adjusted it requires no further attention. No special apparatus needed to receive Radiophone messages over limited distances. Same transmitter equally effective for both telephone and telegraph. Throw a switch and telegraph; throw it back and talk! Not an experiment or an impractical instrument. Absolutely perfect in performance and guaranteed to operate as claimed when instructions are followed. Add the DeForest Oscillion Radiophone Transmitter to your set and you can send messages by telegraph or telephone. Its cost is not prohibitive and it is the coming development in Radio Service. Find out all about it- ? Send for the DeForest Catalogue A 56 -page book full of vital Radio information for the Amateur, including wiring diagrams and other data. Sent postpaid for 10 cents in stamps. Send for yours today. DeForest Complete Radiophone DEFOREST RADIO TELEPHONE Transmitting and Receiving Station & TELEGRAPH COMPANY Type "O,' "A C," Oscillion Transmitter for Radio Telephone and Telegraph (left); Type Inventors and Manufacturers of T -200 Multiwave Tuner (center), and Type P -300 Combination Audion- Ultrandion Detector and One-Step Amplifier (right). This outfit comprises a complete Radio Telephone- Telegraph Station High Grade Radio Apparatus. for both transmission and reception. The instrumente may be purchased separately. Send for a catalogue and get complete details. 1399 Sedgwick Avenue New York City.

ariAl\kftihhhMNhhtihhh`lh.._ LICENSED BY DE FOREST AUDIOTRON The Original Tubular Vacuum Amplifier The AudioTron Vacuum Tube is now manufactured and sold as a genuine audion licensed under DeForest Patents Nos. 841,387 and 879,532 to be used only for amplification in radio communication and only for experimental and amateur purposes and only in audio frequency circuits. The AudioTron has a double filament of special thorium tungsten and the operating life is over 2,000 hours. No special socket is required. The electrical and mechanical dimensions result in a heavy plate current and corresponding signal strength. Plate voltage under 40. Our guarantee insures satisfaction. PRICE $6.00 EACH If your local dealer cannot supply you we will ship postpaid when cash accompanies order. The AudioTron Exclusive Guaranty: Each and every AudioTron is guaranteed to arrive in good condition and to prove fully satisfactory. Replacement of unsatisfactory tubes will be made free of charge. AudioTron Audio -Frequency Transformer $7.00 Laminated closed core, two coil type. DEALERS:-Write for our attractive trade Proposition. AUDIOTRON SALES CO. Lick Bldg. SAN FRANCISCO, CALIF.

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1328 ELECTRICAL EXPERIMENTER April, 1920 Practical Chemical Emperiments Mesco Radio Buzzer By PROF. FLOYD L. DARROW With Shunt Resistance - (Continued front page 127) U. S. Navy and U. S. Army Standard The Radio Officers of the NC Planes, after testing all other buzzers, decided to use the " Mesco" on their radio equipment. The R -34 was equipped with two Mesco Radio Buzzers. Why? Because of its reliability and constancy in operation; greater output efficiency; ease of adjustment; unaffected by extreme variations in weather conditions; exposed wires eliminated. Sparking is almost entirely eliminated, so that the energy lost in light and heat in the operation of other- buzzers is here conserved and radiated in the form of oscillating energy. This buzzer maintains a constant note and is recommended as an exciter for checking wavemeters where pure note and ample energy are required. List No. 55, Mesco Radio Buzzers. Price $2.05. Get a Copy of Our Complete Wireless Catalog and Order All of Your Radio Material from One Source of Supply and Save Trouble. Send 25c for a Copy of Wireless Manual and Catalog. Ready May 10. You cannot get satisfaction from wireless instruments unless they Here You Are, Boys. Make Your Own GcS are absolutely perfect. The slightest imperfection in construction de- Light for Your Lab. stroys their efficiency. We offer for sale wireless apparatus only of A Gas Formed by Boiling Borax, Sulfuric Acid and Alcohol Gives a Beautiful Green the highest quality, guaranteed to be mechanically and electrically Flame When Ignited. perfect. Our combined Manual and Catalog illustrates and accurately describes the uses of standard radio instruments and should be of great assistance, not only Put the apparatus together as shown in to the amateur but also to the professional user and experimenter in selecting figure 8. Then fill the chimney two -thirds proper radio material. full of lumps of calcium carbid and pour 25c for this Manual, issuing water into the bottle. Open the pinch cock We make a charge of and the water will rise thru the disc and a coupon redeemable on an order for $5.00 or more. coming in contact with the carbid will It is the last word in wireless catalogs. Send for a copy now. generate the acetylene, which in a few You cannot afford to be without one when You want to buy. moments may be lighted at the burner. MANHATTAN ELECTRICAL SUPPLY CO., INC. PRODUCING A GREEN FLAME New York, St. Louis Chicago, San Francisco, In a small flask place a mixture of 3 17 Park Place. 1106 Pine St. 114 So. Wells St. 604 Mission St. grams of borax, 3 c.c. of concentrated sulfuric acid and 20 c.c. of alcohol. In the neck of the flask insert a stopper and short length of glass tubing. Over this, as shown age in figure 9, mount a short length of medium N-200 Po. sized combustion tubing. Boil the mixture WiewrelBig ess Catalog and 10140 and light the vapor issuing from the top D UCKS Page Catalog of the large tube. The result will be a Electrical brilliant green flame. The wireless catalog mailed for 12c and the electrical catalog for 6c, either in stamps or coin, which amount you are privileged to deduct GENERATING COAL GAS. on your first order of $1.00. Catalog positively not sent otherwise. Arrange apparatus as shown in figure 10, This edition of our wireless catalog is the most complete and elaborate placing in the hard glass test tube some we have ever put out. It embraces everything in wireless worth while. pulverized soft coal. Heat the tube strong- As an enclyclopedia of information it is invaluable. It is printed on ly with a Bunsen burner flame and pres- excellent paper and with a beautiful cover. Your amateur friend will tell you that there ently a gas will be given off which may never has been any wireless catalog to take the place of Duck's, and above all, that you be lighted at the end of the delivery tube, can absolutely rely on the quality of every instrument listed in this catalog. In a word where it will burn with a luminous smoky it is all worth while catalogs in one. flame. A big improvement over our In the condensing tube will be found a former model. Primary divided tarry distillate, which is commercially into four sections, with three known as coal and is the source of a dead end switches, greatly im- tar proving selectivity. host of organic compounds. Secondary divided into three In the hard glass tube will be left a sections, with two dead end residue coke. switches, eliminating harmon- steel gray of ics. The change in the construction of the guide rod support makes it possible to obtain a looser coupling. It is a wonderful improvement over our old model both in performance and appearance. Only $23.50. NEW MODEL 5BB. NAVY TYPE RECEIVING TRANSFORMER

The secondary on our new type Arlington is divided into three sections with two dead end switches eliminating dead end effect and harmonics and giving greater selectivity. The end support is similar to that on our. Navy type permitting a looser coupling. It is a beautifully finished instrument.

Price only $12.50 Even Coal Gas Generation Is Not Exempt, Provided You Have Two Test Tubes, a OUR IMPROVED ARLINGTON RECEIVING TRANSFORMER Burner and Some Sort of a Stand to Hold the Same. The Gas Coming From the Small Tip in the End of the Terminal Test Tube Can THE WILLIAM B. DUCK CO., 230 -232 Superior St., Toledo, Ohio Be Ignited and Will Be Seen to Burn With a Luminous Flame.

You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1329

PREPARATION OF WATER GAS. "ASK ANYONE WHO HAS USED IT" Water gas is one of the most important fuel and illuminating gases and may be prepared as follows : WHAT OUR PATRONS SAY Set up apparatus as shown in figure 11, "I can hear the signals three times as loud and clear as I could with using a hard glass combustion tube 18 my old receivers." (Name on request.) inches long and 44 of an inch in diameter. In the end of the tube next to the flask of boiling water insert a roll of previously ignited asbestos paper, into which the tube BRANDES from he boiling flask should lead. The asbestos is to prevent the breaking of the tube from the condensation of steam. In the combustion tube place lumps of char- WIRELESS coal and heat them to redness with a 4-tube burner. Then boil water in the flask and HEADSETS pass the steam over the glowing charcoal. CLEAR TONE LIGHT WEIGHT REFINING CRUDE PETROLEUM DEPENDABLE SERVICE Arrange a distilling flask and condenser exactly as they were for the distillation of Score 100% efficiency in actual use. alcohol, as described in the February issue. Be sure all connections are tight. Sharp, Unblurred, Readable Signals "Superior" In the flask place some glass beads and assured by Set, 2000 ohms, $7 fill it half full of crude petroleum. The thermometer used should be able to regis- BRANDES MATCHED TONE" ter as high as 360° C. Having provided a wet towel to smother the flames in case Exactly matching the tone of both receivers in each set and thus eliminat- of accident, begin heating the flask. Notice ing all confusion due to unmatched harmonics. that the petroleum very soon begins to boil. Buy a Brandes Superior Headset and use it critically for ten days. Catch the distillate in a small dry flask and Then, if it doesn't come up to our claims or your expectations, return the has risen to 70° C., it and your money will be cheerfully refunded. Test it- compare with when temperature TRIAL others -for sensitiveness, clearness, distance. Prove for yourself the replace it with another flask. Continue the fine quality, the "matched tone." The two diaphragms toned exactly distillation changing the receiving flask alike, strengthen at the signals and prevent blurring. Used by many U. S. 120° 150° OFFER Government experts, and experts abroad; by colleges and technical 80° C., C. and C. stopping when schools; and by professionals and amateurs everywhere. 300° C. has been reached. This will give SEND five fractions and a thick tarry residue in 4c FOR CATALOGUE E the flask. C. BRANDES, Inc. 32 Union Square The products are practically the same as Room 814 New York City, U. S. A. the petroleum products sold on the market: WIRELESS RECEIVER SPECIALISTS Petroleum ether Light gasoline Heavy gasoline Complete Line of Brandes Receivers for those in Canada. Send stamp for Pamphlet "E" I Naptha IScientific Experimenters, Ltd., 11 St. Sacrament Street, Montreal, P. Q., Canada Kerosene Lubricating oils 1 Obtained from Vaseline the residue in Parafine the flask. Pour the residue from the flask while it is still hot and rinse the flask with gasoline. Experimenters! FLASHING POINT OF KEROSENE A sure index to the grade and safety of FOR RESULTS USE kerosene is its "flashing point." This is the temperature at which the vapor rising from oil will "flash" when a flame id brought near it. In a tin cup placed over a Bunsen burner pour four tablespoonfuls of kerosene. Try to light it with a match. If it, is a good grade of oil you will not succeed. Gently Triode heat the cup and contents and at frequent intervals try to light the vapor, at the same (Trade Mark) time taking the temperature. The temperature at which the vapor will just ignite is approximately the flashing point of the oil. The flashing point of good grades of kerosene is from 120 F. to 140 F. If the oil does not simply flash and go out but continues to burn you have pasty the flashing Vacuum Tubes point. In that case put out the flame by covering the cup with a glass plate and Immediate Delivery allow its contents to cool. Every minntt $ 7.00 Each Postpaid or two test with a lighted match. Th4 lowest temperature at which the vapor will FOR DETECTORS OR AMPLIFIERS just ignite is the flashing point. WILL FIT ANY STANDARD FOUR -PRONG SOCKET (The next paper will appear in an early TRIODE Appliances also include Eaton Oscillators, issue.) Two -step Amplifiers, Vacuum Tube Sockets, Grid Locks andAudion Frequency Amplifying Transform- ers. When ordering radio apparatus specify TRIODE to insure receiving only apparatusandappliancessup- ATTENTION!!! plied by the Wireless Specialty Apparatus Company. RADIO, ELECTRICAL and CHEMICAL Catalog will be sent on receipt of 25c in stamps. laboratory owners, refer to our monthly laboratory contest on Page No. 1288, for prizes offered for laboratory pictures. We have not received any worth while r'hotns for several months. Now Is the time to get busy with WIRELESS SPECIALTY APPARATUS CO. that camera and take a photo of your "Lab," and do not forget one of yourself! The more good ones we get, the more we will pub- BOSTON, U. S. A. lish,-so send us some "real Lab" photos by the very next mall, won't you? You benefit by mentioning the "Electrical Experimenter" when writiag to advertisers. 1330 ELECTRICAL EXPERIMENTER April, 1920

MIGNON "RW4" WEIT Apparmtus By "SPARKS ", C. E. Radio U. S. N. UNDAMPED WAVE (Continued from page 1285) ments are purchased intelligently and care- RECEPTORS fully, the amateur station can pick up signals from stations many thousand miles distant. Loose Couplers TRANSMITTING APPARATUS. The prevailing question in Amateur Loading Coils circles in regard to transmitting apparatus seems to be whether or not it will be "arc Variometers or spark." Personally, I am firmly convinced that the spark will stay for some NO Amplifiers time to come. The arc is being widely developed commercially, but so is the spark, "RW4," Size 12" x 9" x 6 M" Strongest, Most Distinct Signals and for short wave lengths, the spark has proved the more satisfactory to date. In view of the rapid development of the arc, IMPORTANT NOTICE two or three manufacturers have put an The Mignon System Apparatus, "RW1," "RW2" "RW3" and "RBD8" amateur undampt wave transmitter on the are no longer manufactured and are superseded by the improved "RW4," market, all of which are excellent sets of "UW1" and "BD1." These apparatus are manufactured exclusively by the their kind. They are capable of doing very MIGNON MFG. CORP., sole owners of the Mignon System Patents. (See good work with the small amount of power U. S. Letters which they consume. They may also be Patent No. 1329672.) used as radio telephones, with a slightly INFRINGERS WILL BE PROSECUTED. decreased range than when used as tele- MIGNON MANUFACTURING CORPORATION, - - NEWARK, N. J. graph transmitters. A vacuum tube transmitter is also on the market now, and looks promising, but DAMPED AND UNDAMPED WAVE the choice today lies with the individual APPARATUS FOR ALL PURPOSES Amateur. It will probably mean that a bunch of us will have to install arcs at the Endorsed by Radio Department of D., L. it W. R. R. Co. SUPERIOR same time or let the old spark do the work for a few years longer. She has done so Write for Literature. MIGNON SYSTE well in the past, and there is still such APPARATUS room for improvement in spark sets that MIGNON MFG. CORP. it's a little early to think of undampt waves for two hundred meter work. Let's turn NEWARK, N. J. our attention to better results with the Dept. E spark sets. Develop the non -synchronous. rotaries. There is room and then some for improvement there. Get after them and let's see what can be done toward mak- Bunnell Instruments ing an ideal spark set. Go after oil con- Always Satisfy densers, or at least those with reliable insulation. Oscillation transformers should Our Jove Detectors be wound with heavy ribbon and of a width Simplest and Best- - that will count -not quarter inch stuff, or even half. Make one or one and a half Sample by Mail, $1.80 inches wide for a one -kilowatt set. Trans- Tested Galena Crystals, 25c per box. formers, too, should be of proper design and are often better purchased than made Our Keys, Spark -Gaps, Condensers, at home. Above all, keep your leads short, Transformers, etc., are High Grade, Jove Detector and heavy, and get enough turns into your (Patented) but inexpensive. oscillation transformer to chase the energy in the Send Stamp for our New Catalog 42 E. across. What will a quarter turn primary do? -make it one and a half, and J. H. BUNNELL & CO. 32 Park Place, New York cut down your leads elsewhere. (Marconi Licensee) There is a vast field for the development of a good spark coil set. We don't all live in the city where we can have "AC" by turning a switch. Get a spark coil with a good vibrator or substitute some sort of Build Your OwnWireless Receiving Set interrupter for the vibrator -they are woe- Think of the pleasure and practical experience you will enin in making your own set. You can save at least $25.00 by buying the parts and assembling it yourself. This is not a tov, but a regular. large sired fully poor at best. Then see what you can set (16 "xS "x6') capable of receiving messages ranging in wave length from 170 to 2,500 meters. We will furnish you with large, full sized blue -print and full information do with it, and if you hit something real concerning winding of coils, mounting of instruments on panel, good, let us all know about it -don't keep it "book up " -in fact complete detailed instructions, written in plain easy to understand language. to yourself. In your spark coil experiments, tho watch your wave, for the spark coil OUR OFFER IS THIS anti little boy are the pests of the "relay Send $1.00 and we will send you the blue -print and instruction sheets -also prices of all parts. When you order at one time $5.00 game," and no one wants to be clast with or more worth of parts. you may deduct this $1.00 from the total. them. Since the blue -print and instructions alone are worth $1.00 and since we can save you money on wireless material, you cannot Get busy now, and let's see if we can't possibly lose. So send $1.00 today before this slips your mind and start making your set as soon as possible. have some really good stations this season. We had scores before the war, but we K & G WIRELESS SUPPLY CO. want hundreds now. Let's have descrip- Dept. 15A, 152 Chambers Street New York City tions and data on the good stations and apparatus so that we may all benefit. I have made receiving outfits such as described herewith, and they have given me wonderful results. Lying in the harbor AMATE V iI at Antwerp, Belgium, quite a way inland, full description of the most I had no trouble in getting Arlington's 1RELESSeifcient detector in the Held today spark, Tuckerton's alternator and several 'rested by Marconi Wireless Telegraph Co. and U. S. Government. Instantly adjustable U. S. arcs, with one bulb. If they prove at a constant pressure. I L. STEWART BARR, Inventor, Vice -President of The Service Radio School as satisfactory on short waves as they THE BARR MERCURY -CUP DETECTOR Dept. A, The Wyoming, Washington, D. C. have proved on the long ones, I'm going to describe them for you fellows. Let's all do that. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER ,1331, Electricity Foils Germ pax Seals ANNOUNCEMENT By FRED C. KELLY (Continued from page 1251) SUMMER session One of the five men had establisht himself as a lookout in a public washroom down opens May Ist. the corridor, a few paces from the outer door of the consulate. Complete course pre- It was arranged that if danger should threaten he would walk down the corridor paring you for license and give two quick taps on the door. On and best paying posi- the night mentioned he did hear some one coming up a stairway. Quickly he gave the tions. Rapid progress, alarm and then hastened back to his secret post in the lavatory. Then men who had individual attention, been operating on the filing cases flicked off size. their electric light, which was a specially classes of limited arranged one that illuminated only a limited Write for descriptive area. They gained hiding places under tables and behind desks barely in time to be A New Profession literature. out of sight when the watchman, if such it was, opened the door and peered inside. But he was there evidently just as a matter of AUTOMOTIVE Y. M. C. A. routine, in the course of his regular rounds, and did not chance to notice anything un- ELECTROTECHNICS usual about the office, tho one of the search- RADIO SCHOOL ers was lying within four feet of him. After is open to YOU ! The field is Broadway a moment or two he continued on his way. Marcy Avenue near time to BROOKLYN, N. Y. Every detail of the plan of restoring the rapidly growing - the safes and filing cases to their usual condi- train is ripe ! Telephone, Williamsburg 3800 tion was carefully thought out. One man was even assigned to the job of seeing to it A most complete equ.pment that the dust on the filing cases was about as it had been. He swept up dust from the of standard apparatus and test- floor and placed it where finger marks ing instruments in charge of might have showed. RADIO APPARATUS The visits of the five men continued, be- Prof. E. L. Consoliver, well ginning probably late in April, until the known Automotive Specialist, early part of July, and it is believed that Distributors of Reliable Experimen- corn- tal and Laboratory Radio Apparatus in the early morning of the Fourth of July, and a staff of experienced, for High Schools, Colleges and by way of patriotic coincidence, the last of petent instructors.- Automobile, Individuals. the German documents were removed from the consulate. Airplane and Marine engine, On this final visit the five men arranged to open a section of filing cases and also the IGNITION More steel trunk, which was locked and sealed Try about as the safes had been. It had been than our a left until the last, because, for some reason, STARTING store service the men had an idea that the papers it contained might be of the least importance. LIGHTING The truth was that the Germans had intended this trunk to contain the most im- practically and thoroughly taught in find portant documents of all. courses of convenient length and At F. D. Pitts Co., Inc., you will But the men succeeded in opening an exposition of reliable radio appa- when moderate cost. ratus and supplies from the foremost the one remaining section of the filing cases No and this steel trunk they had a surprise that manufacturers of the country. left them breathless. 2 Years other store has such a complete line the steel strong of equipment, nowhere else is such Both the filing case and 6 Months an opportunity to choose from the products box were already empty! of so many radio manufacturers. A fea- They had been carefully sealed up by the 3 and 4 Months ture which must appeal to experimenters Germans without containing any papers at is that we keep things in stock. Immediate courses, -day or evening. - delivery! Give our service a trial! Send all. It is now pretty well understood that 6 cents in stamps for .few catalog. Every the papers had been secretly taken away by While You Learn" experimenter should have it. one of the Germans who was intrusted with "Earn the job of storing and sealing them up. Just system permits you to assist your- F. D. PITTS CO., Inc. what personal use he intended to make of Dept. D them never has been disclosed. They were self toward paying expenses. 12 Park Square, Boston 11, Mass. so I have been found by the merest chance, Opens March 29th. told, in two large suitcases and a steamer New Term Clip the coupon NOW for Cata- trunk in an obscure storage warehouse some log and full particulars FREE! the weeks later. BOYSGet1 J most at- were tractive warning sign When discovered these papers made. Your den is In- promptly turned over to the United States School of Engineering of complete without it. It so happened that they Printed In red on white Government. Milwaukee cardboard 71/4"x11% ", reached the possession of Government offi- Reduced to 10e each. 181 -373 Broadway Milwaukee, Wis. Send 2e for postage. cials at about the same time as the other Don't buy plain print- papers taken by the five adventurers from CLIP HERE ed signs. We are giving away hundreds of expen- the consular offices. FREE sive wireless instruments, electrical appa- UNKNOWN. ratus. supplies, etc., for selling a household article FIVE ADVENTURERS that goes like wildfire. School of Engineering of Milwaukee, this of Thus it came about that the United States Willin¢te Ie vewill epo.ltof 75 cento for Milwaukee, Wisconsin. and and ,Justaendformformetton. Government does not know even to this day If d,ssntiefied. deposit will beornterned the papers were 181 -373 Broadway, L. BECK NOVELTY HOUSE how, when or by whom 1298 Carroll Street Brooklyn, N. Y. captured. Gentlemen : I am interested in Automotive Electro- Having once obtained the papers, the technics. Kindly send full particulars. on You can be quickly cured, if you Government set translators at work them. The variety of information then Name acquired was really astounding, for the STAMMER seized correspondence showed how intri- Address Send 10 cents coin or stamps for70 -page book on Stam. cately Germany had allied its industrial mering and Stuttering, its Cause and Can' It tells how I [ cured myself after stammering for 20 years. with its espionage system.-New York Age Education y Benjamin N. Bogue, 765 Bogus Bldg., Indianapolis Tribune. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1332 ELECTRICAL EXPERIMENTER April, 1920

TEWNO WIRELESS PRODUCTS OF QUALITY att1e In all of the products shown below you will find we have used the finest of materials and the most accurate The Tracer workmanship. All material guaranteed against factory defects, as it has always been a principle with us to manufacture products of superior type but at a reasonable price. (Continued from page 1242) "Tewno" Variable Condenser i The rotary variable condenser is a necessity for all experimental wireless work and one or two of them are to be found in almost any wireless station. The two most popular types are the 43 plate and 21 plate with capacities of .001 mfd. and .0005 mfd., respectively. tom of which is attached a driving wheel The large size has 21 rotary aluminum plates and 22 stationary aluminum plates. The small size has 10 rotary and 11 stationary plates. with a perifery of sharp teeth preventing The ordinary rotary variable condenser is mounted in a cheap round the Tracer from slipping off the table. metal case with a cheap composition top and coarse scale. its plates are 0.15' thick and the shaft is 3/16" in diameter. When a distant transmitter is actuated, The "Tewno" Rotary Variable Condenser has two genuine "Formica" motor in the Battle Tracer is simul- ends, a clear glass case, e. Y.' shaft and plates .0_4". thick of a this special grade of aluminum. However. the biggest feature in favor of taneously operated, causing the driving our condenser is the form of end -piece used. It is square. facing the the to move slow- operator. It is net necessary t s b:o.: over ono's hand to eco the scale, wheel underneath Tracer as was the case in the old upright type of condenser. The scales on carrying the Tracer with these instruments are calibrated to 2% degrees. ly along the table, We recommend our 43 plate condenser for primary and secondary it. The distance traverst in this way is tuning on sets of fair range and for use In oscillating circuits. Our to 21 plate condenser 13 well adapted to short wavo tuning fur use it exactly proportional the actual distance small wave meters and a great variety of work calling for a small by the ship itself. variable capacity. traverst Do not be fooled by an instrument that is 'Just as good." These Lines of perforations are made by the are to date the best condensers on the a.aateur market. teeth of the driving wheel to trace the No. 53-21 plate -.0005 mfd Price, $4.75 No. 43-43 plate -.001 mid Price, $5.50 course of our own vessel. The inner dial "Towne" Wave) Receiving Transformer (S:sort likewise is made to turn by a third motor, Directly prior to the war, the amateurs were doing wonderful work with specially made short wave couplers of their own construction and the picture of the ship engraved upon it and through the use of Armstrong circuits or with straight audion circuits. Up to that time no manufacturer had placed such an will show the directipn in which our vessel instrument on the market. is traveling. In other words, the engraved In our short wave receiving transformer the amateur will find the embodiment of all of his ideals. It is designed f"r use on a nateur outline of the ship on the movable dial is aerials of from 150 to 200 M. fundamental wave length and with in the rotation of the driv- a small capacity of variable condenser across the secondary will kept plane with easily tune to 600 M. The windings are of the very efficient type ing wheel carrying the Battle Tracer along known as bank wound (an expensive process) and are of heavy stranded conductor in silk sleeving. They are wound upon non- the table. shrinkable tubes. Variation is obtained by means of two U-point switches mounted upon "Formica." Switches and conta-te are The pointer (D) heretofore described satin finish, nickel plated, which is in accord with the Govern- going to the outer surface of the movable ment's specifications. All other metal work Is polished and nickel plated. Woodwork has a beautiful hand rubbed mahogany finish. dial and the inner surface of the fixt dial No. 23 -Price $12.00 Order today as orders will only be filled in rotation as indicates on the outer dial (A) the true 1hry come in. Remit by postal money order or check. compass bearing of the target, and when The TEWNO COMPANY, 150-152 Chambers St., New York City read with reference to the inner dial (B) indicates the true bearing of the target with respect to the ship. A second pointer (E) controlled by another electric motor passes to the smallest TRACO QUALITY of the three dials and gives a reading of the speed of our own ship transmitted, as RECEIVING TRANSFORMERS has been stated, on the revolution converter. Used the world over. Insist on the genuine, built by its originators. Substitutes are expensive, irrespective The enemy arm is continually being of design. We absolutely guarantee our tuners to give moved in accordance with the range, corn- the maximum signal volume. Delicate refinement. uninterrupted service and high class working from the target bearing transmitter. manship unite to make TRACO tuners On this arm is located a small carriage the standard whereby all others are and on judged. It your Dealer having two pencil points, traveling does not handle them, tiny rollers. The distance of this carriage order direct frdm us. to the center of the Tracer is directly pro- LIBERTY DETECTOR portional to the range of the target. This VALVES. RADIO AM- a motor, PLIFYING PHONES, distance is regulated by fourth type used by the actuated by the auxiliary range transmitter. UNITED STATES. of the battleship are BRITISH and FRENCH On the big gun turrets GOVERNMENTS, now the range -finding instruments. These in- in stock, for sale. struments consist of an arm 30 feet long Send stamps for The Famous 5A and 5C Models bulletins. with mirrors and lenses at each end; one is set at a 90 degree angle and is moved until THE RADIO APPARATUS CO., Pottstown, Penna., U. S. A. the operator's eye, looking thru a hole near the center of the instrument, spots the enemy. Immediately he attempts to twist the other end mirror so that the enemy may be observed at the same time. The "DEPENDABLE" angle thus formed allows the computation of the range. The range thus determined Radio Equipment is transmitted to the Tracer room, where DORON BROTHERS ELECTRICAL CO. an operator turns the Auxiliary Range Transmitter in accordance with the in- Hamilton, - - Ohio formation he receives from the range -find- Manufacturers of ing instrument. In this way communica- Binding Posts, Switch Points, Special Screws, Nuts, Parts, Variable tion to the Tracer is obtained. Condenser Shafts, Separators, Plates, etc. Automatic Screw Scales are provided for reading the range Machine Punch directly. Likewise, pencil points operated and Press Products of any kind. Get our prices on the ends of magnets controlled by a en your Parts. clock, produce dots along side of the course. Have you a copy of our Radio Catalogue No. 9? It's free. Now, then, let us see what all these results come to. First, we plot automatically by communications directly from the propeller STORAGE BATTERIES shafts and gyro -compass the course and FOR WIRELESS SERVICE speed of our ship on a large sheet of paper. This is one definite factor that is known. Batteries especially adapted for the amateur operator are described and illus- Secondly, instruments, on the mast -heads will be on trated in our new Bulletin No. 175, copy of which furnished request. of the vessel, keeping a "line" upon the enemy vessel, cause the enemy arm to trace THE ELECTRIC STORAGE BATTERY CO. another course upon the table. See dia- The largest maker of story re batteries in the world 1888 PHILADELPHIA, PA. 1920 gram herewith. New York Boston Chicago Washington Denver San Francisco Cleveland All of this is figured out to mathematical Atlanta Pittsburgh Minneapolis Kansas City St. Louis Detroit Rochester ratios so that if Special Canadian Representatives, Chas. E. Goad Engineering Co., Ltd., Toronto and Montreal accuracy and system of the enemy is eight miles away, the pencil You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1 333

line for the enemy will extend out a definite radial distance from the center of the Tracer proper. If the distance between the RADIO two ships decreases the course of the both ships will approach each other as clearly OPERATORS noted on the Tracer table chart. Should at any time one of the instruments lose bearing of the enemy, the $125.00 per month operator at that observing station releases a button and no mark is placed upon the and upward plus Tracer table until he again finds the range. Thus we now have the complete and defi- all expenses. nite data of the speeds of both ships and the courses they are pursuing. Modern Equipment- If we could fire a shot at the instant that we obtain the enemy's position, it would be Special Short Course very easy to put the other vessel out of Individual Instruction commission, but it takes time to elevate the guns and make other necessary changes. Finest Staff of teachers Hence, a matter of predicting range is made use of. Calculating our own ship's available position by a very simple adjustment which fits on the Battle Tracer, and knowing that Dormitory- Swimming we ourselves are not moving to any ap- Pool preciable extent, it is simple enough to pre- determine exactly what position the other YOU ARE BADLY if you lick Call or write for ship may be in, in say one minute from High Schgl illustrated booklet that period. HANDICAPPED Accordingly, instruction is sent to the You cannot attain business or social Y. gunners, the guns pointed, and the in- prominence. You are barred from M. C. A. Radio School stant that the ship. gets into the position a successful business career, from Dept. R which had been predicted for it, the order the leading professions, from well - 152 E. 86th Street, New York, N. Y. to fire sends out a broadside salvo which in- paid civil service jobs, from teaching destruction of and college entrance. In fact, em- "BEST RADIO SCHOOL IN variably causes marked THE EAST" enemy life and property. Strange to say, ployers of practically all worth -while even the time required by the shells in positions demand High School train- reaching their intended victim, is allowed ing. You can't hope to succeed in for. the face of this handicap. But you A Real Electric The device is worked out to the greatest can remove it. Let the American accuracy, even to a correcting device for School help you. tides, winds, ocean currents, etc., and provi- sion is made for the condition of the ship's FIT YOURSELF FOR A TELEPHONE hull -all automatically. This Course. At the revolution converter is an auto- BIG FUTURE which has been THAT WILL OPERATE prepared by some of America's leading pro- matic indicator which corrects the speed of fessors, will broaden your mind, and make UP TO 200 FEET ON 2 the motors in the Tracer table in accord- you keen alert and capable. It is complete, ance with the chart used. These charts can simplified and up -to -date. It covers all sub- ORDINARY DRY jects given in a resident school and meets all be set to a scale of 1-30,000, 1- 40,000, 1 -60,- requirements of a High School training. BATTERIES 000, 1- 80,000. From the first lesson to the last you are The advantages of Tracer equipment on carefully examined and coached. Price of whether the vessel per set any vessel regardless USE TINE ONLY (2 Phones) $1.50 is engaged in war or not, are manifold. SPARE Chief among these are the uses that it can Most people idle away fifty hours a week. a ship's Probably you do. - Use only one -fifth of your 2 Transmitters be put to in recording accurately wasted hours for study and you can remove and 2 Receivers $1.00 log, plotting at all times the course of the your present handicap within two years. You vessel and being of a great advantage in will enjoy the lessons and the knowledge Send stamp for catalog you will gain will well repay the time spent what is known as dead reckoning. By this, in study. we mean that a vessel may leave a port INLAND- SPECIALTY CO. during a storm and perhaps two or three days later, may attempt to locate itself, but TAKE 10 LESSONS 1562 N. Robey Street to the fact that there is no sun in So that you may see for due yourself how thorough CHICAGO, ILL. order that observations may be taken, it and complete our train- does not know its latitude and longitude, ing is. We invite you to it cannot recall how far or take ten lessons in the High School Course- simple because or any Course of specialized training in the how fast it traveled, even tho compass Coupon below- -before deciding whether Radio Men readings have been carefully jotted down you wish to continue. If you are not then in submarine work where satisfied you are not out one cent. We abso- Wireless Amateurs hourly. Similarly, lutely guarantee satisfaction. On that basis We carry a complete line of Grebe, a vessel is submerged, probably for days, all you owe it to yourself to make this test. that is necessary, is to determine its loca- Check and mail the coupon NOW for full De Forest, Marconi, Murdock, particulars and Free Bulletin. Clapp -Eastham, and all other lead- tion, on the day it sailed, and the Tracer of Radio Apparatus,from will tell you where you are any time you ing makes made correc- AMERICAN SCHOOL Contact Points to Complete Sets. may desire, having already OF CORRESPONDENCE tion for tides, winds, and vessel conditions. Dept. H. 264, Chicago, Illinois Agents for RADISCO Apparatus Photos Courtesy Sperry Gyroscope Com- Coils, Batteries, Indicat- - - 4 :KEY TO ,SUCCESS Including "B" >TRAIN;N -TI1$ ing Dials and other parts distributed by pany. them. Mail orders given prompt attention. Please explain how I can Aid Open Evenings until 9:30 P.M. qualify for the position marked x KELLY & PHILLIPS 312 Flatbush Avenue, Brooklyn, N. Y. ATTENTION!!! Telephone Sterling 2380 and CHEMICAL ..High School Graduate ..Lawyer RADIO, ELECTRICAL ..Electrical Engineer . .t3uslness Manager laboratory owners, refer to our monthly ..Elec. Light & Pr. Supt. ..Certified Pub. Accoun't. 1288, for _.Hydroelectric Engineer ..Accountant & Auditor laboratory contest on Page No. ..Telephone Engineer ..Bookkeeper prizes offered for laboratory pictures. We ..Telegraph Engineer ..Stenographer Become a not received any worth while photos ..Wireless Operator ..Fire Insurance Expert have ..Architect ..Sanitary Engineer for several months. Now is the time to get ..Building Contractor ..Master Plumber Licensed busy with that camera and take a photo ..Civil Engineer ..Heating & Vent. Eng. and do not forget one of ..Automobile Eng. Electrician! of your "Lab," ..Structural Engineer ..Automobile Repairman yourself! The more good ones we get, ..Shop Superintendent ..Airplane Mechanic the more we will publish, so send us ..Steam Engineer ..General Edu'n Course Read page 1235 - ..Draftsman & Designer ..Common School Br'ch's some "real Lab" photos by the very next ..Photoplay Writer ..Employment Manager mail, won't you? Foreman's Training Course You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1336 ELECTRICAL EXPERIMENTER April, 1920

on the desk, on the body, on the floor, on the door knob-inside or out-not anywhere. It's beyond me." COPPER AERIAL WIRE Radio Diagrams "Couldn't come in thru the outer office, ch ?" Fenner's eyes were roving over the 50c FOR 100 and Formulae room. Frank shook his head slowly in negation. "Three and the head book- FEET in Loose Leaf Form girls We are putting on another sale of absolutely keeper out there all evening, working over- pure No. 14 gauge copper aerial wire at 50c The publishers of the CONSOLIDATED time. All swear not one of them has been per 100 feet. We also have in stock some of RADIO CALL BOOK have completed the in this room this evening. Corey came in this wire in No. 12 gauge the price of which preparation of diagrams and instructions is 80c per 100 feet. All orders must be ac- on: thru the outer office -the only way he companied by parcel postage and insurance Measurement of Capacity of a Condenser. could come in, for this office has only the charges. We make no C. O. D. shipments. (Substitution Method.) Calibration of a one entrance -and closed the door. About Prices subject to change without notice. Variable Condenser. Two Diagrams and half past eight one of the girls opened the Curve No. 1 Induction coils -primary 1 ohm, secondary Measurement of Inductance of a Coil or Circuit. door to come in. She saw that something 55 ohms -shipping weight 2 lbs. each. SOc Two Methods-Two Diagrams No. 2 had happened to Corey, and she didn't Desk telephones-standard type just as used Measurement of Distributed Capacity of an In- cross the threshold. All of them had in all large cities and towns, is equipped with ductance. Diagram and Curve No. 3 sensitive transmitter and receiver, switchhook Measurement of Fundamental Wavelength of sense enough to stay out. They telephoned with genuine platinum contacts and hard an Antenna. Three Methods. Three Dia- for us. I was the first man in." rubber mouthpiece. The telephone is n'ckel- grams No. 4 "No other doors ?" plated and is slightly used but guaranteed Measurement of Wavelength of Distant Trans- "Nope. Only one way in. Thru that absolutely by us. The new price on this mitting Station. Two Methods. Calibration telephone is $10.00. The shipping weight of a Receiving Set. Two Diagrams. No. 5 office." is 5 lbs. Our price $3.50 Measurement of Effective Antenna Capacity. Fenner was gazing at the wall on the Two Methods. Two Diagrams No. 6 We can furnish the same as above in a wall Measurement of Inductance of Antenna and a street side. "Did you open that window ?" type telephone being equ'pped in addition Third Method of Measuring Effective Capac- he asked. with a 1000 ohm ringer. Cabinet finished in ity Antenna. Diagram No. 7 dark oak. The new price on this telephone of One "No. It was open. But it might as well is $14.50 but since they are slightly used we Measurement of Antenna Resistance. Substi- have bricked up for all the good it's tution Method No. 8 been are closing them out at $4.75. Schematic Wiring Diagram of Regenerative Au- going to do us. Corey opened it himself, Shipping weight 15 lbs. dion Receiving Set Suitable for Receiving no doubt. It's just sixteen stories to the Be sure and include postage and insurance High Power Undamped Wave Stations. Con- street, and you can bet no one climbed up with each of the above items when ordering; nections shown are those used in most Navy otherwise they will be shipped by express and Commercial Receivers No. 50 to it. It's five stories to the roof. One collect. Table giving the value of LC (Product of In- chance in one thousand that any one Send Sc for our illustrated catalogue ductance and Capacity) for wavelengths from climbed down. It would take nerves of 300 to 20,000 meters. Inductance in Micro - henrys No. 100 steel to drop over the edge on a rope, and ELECTRICAL SPECIALTY CO. Table same as above but with Inductance in if some one did have the nerve, they Dept. E -48 -50 So. Front St., Columbus, Ohio centimeters No. 101 couldn't have gotten in that window noise- Schematic Wiring Diagram of Signal Corps Type SCR -68 Radio Telephone Transmitting lessly enough not to warn Corey. And and Receiving Set No. 51 just assuming that they did, they'd surely Schematic Wiring Diagram of Type CW -936 leave a mark doing it, wouldn't they ?" (Navy Submarine Chaser) Radio Telephone Fenner nodded. "They would indeed," and Telegraph Transmitter and Receiver. HAVE YOU HEARD No, 52 he acquiesed. "How about the people in Schematic Diagram of Type S.E. 1100 (Navy the office out there? Are they all above of the immense savings RADIO Flying Boat) Radio Telephone and Tele- suspicion ?" EXPERIMENTERS are making on graph Transmitter No. 53 "All above it," complained Frank, "and all makes of radio apparatus, raw These diagrams and instructions are the most CLEAR, CONCISE, COMPREHENSIVE not only that, but the very number of them material, etc.? and CONVENIENT form of instruction that lets them out without question. It's not has ever been presented. They are printed reasonable to suppose that three girls and Members of this Association on pages size 81/4 x 11. a man, all trusted employees, would con- buy through us at a saving, due to spire to kill their employer without a our wholesale buying. You also Complete Set of 14 Sheets motive for doing so. One of them might can save money and get quick de- try it, or maybe even two, but it's hardly livery on anything advertised in as described, sent postpaid 7O C likely that all four would be against the this magazine. man." Special Offer CONSOLIDATED RADIO CALL "Right you are," admitted Fenner, "I BOOK CO., Inc. thought that myself, but we have to MARKO 4V 60 Amp. storage bat- way teries $7.00 net to members only. 41 Park Row, New York, N. Y. eliminate the possibility of an inside job first. Well, Chief, I don't see that I can Supply limited. do you any good in this matter. It is un- If you are not a member write im- .mossmisssisr usual enough to be interesting, and if you mediately for details. don't mind I'll drop in and have a look around in the morning. Mutual Purchasers Association "Help yourself," gloomed Davidson. "I Dept. E21: -2 -4 Stone Street FREE! FREE! don't believe you can do anything in this New York City. Descriptive Circulars of case myself. I just took a chance. You might have, you know." "I wish that I could have. And I'll look B- BATTERIES it over in the morning on the off chance. OUR "BETTER QUALITY" TYPE Good night, Frank, and good luck. Good American Electro Technical Appliance Co., night, Chief. Come on, Bill," And we 235 Fulton Street New York City left. of 22.5 45 As we walked homeward, Fenner said: SPECIALS day of miracles is not VOLTS VOLTS "It seems that the Audion Detector gone by, after ail. What do you think of 00 15 30 that for a puzzle ?" Panel for CELLS CELLS "I't's beyond me," I replied, soberly. Crystal Detector "The only possible explanation that I can think of is that the man committed sui- 20c nez. Stand for To enable every amateur to use our cide." Jeweler's Time Signal Set, "B E T T E R QUALITY" B Joe stood still and rocked with laughter. De SUPER Bill, Bill," he gasped, "there's only Forest make, Complete with large BATTERIES, they are now offered at "Oh, Eveready "1B" Batteries $25 00 of all. Remember one man in a million -yes, I'll make it a a price within reach suicide by stabbing Without Bulb B- Batteries are sold to you on billion -that commits All parts for the Amateur to build his own that our in the back, to say nothing of a Money -back basis. They are FULLY himself sets. Catalog ready within three weeks. and your money calmly disposing of the weapon just after GUARANTEED, he's dead." CHEERFULLY REFUNDED if not sat- "how Our motto "RETAILING AT "Well, then," I demanded, sullenly, isfied. do you account for the thing ?" MEMORIZE WIRELESS CODE WHOLESALE PRICES." Shipped Our He grew thoughtful at once. "I can't," By ALMOST INSTANTLY Cat. No. Voltage Average Life Price he admitted, "unless BB -154 22.5 4 months $1.25 Express -" 2.20 My method is the short cut. Complete BB -158 22.5 8 months Only "Unless what ?" I asked, as he paused. SBB -3012 45. i year 4.35 chart and full instructions. Two dimes. Audio Tron Amplifiers $6.00 postpaid and insured "Unless- unless -well, I wouldn't want to say unless anything just now. Would C. K. DODGE THE H. S. WIRELESS CO. with me again to- 164 Ross St. Dept, D, Brooklyn, N. Y. you like to go down Box 100, Mamaroneck, N. Y. morrow morning ?" You benefit by mentioning, the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1337

"I certainly would," I rejoined, instantly. "This thing's got my goat." Get The JOY Out RADIO "All right, then. I'll stop for you on a my way down." OF JLIFE TELEPHONE & I lay awake for hours trying to figure WHAT'S the good of out how the thing could have been done. 9Y living at all, if Life is TELEGRAPH There didn't seem to be a plausible ex- just one miserable day after of Merit planation. If the facts in the case had i.nother, full of discomfort Apparatus been handed to me as a sort of a puzzle, I and failure, often of actual Distributors for would have said that it simply couldn't be suffering? You can't enjoy done. And yet-there was the dead man. life, or make a success of DEFOREST Eventually I gave it up and fell into a anything, while you are un- restless slumber. developed, weak, ailing; a MURDOCK -AMRAD sickly grouch whom nobody Next morning Fenner called for me as wants to help along or even MULTI -AUDI-FONE arranged. "Well," he asked, cheerfully, have around. When you PERFECTION have you solved the mystery over night ?" wake up in the morning with "No," I said. "It ecros more baffling a rotten taste in your mouth And Other Prominent Mfgrs. than ever after a night's thought. Have and a weight in your chest; you found the answer ?" with your brain woozy and IMMEDIATE DELIVERIES "Not yet. Do you happen to have a good your nerves all on edge, tired out before you even begin Send Stamp for Catalog pair of field glasses ?" I had, and I produced them. "That's the day, YOU ARE IN A 'fine," said Fenner after examining them. BAD WAY. YOUNG & McCOMBS "Let's go." Dept. 67 Rock Island, Ill. We had no trouble getting into Corey's Put Your Human offices. The body had been removed, and aiRONGFORT practically all traces of the tragedy had The Perfect Man Machine In Order Recognized as the largest and best disappeared. Dyspepsia, indigestion, biliousness, constipa- Fenner dropped into the chair which so tion, nervousness, and a host of other aiiments the hapless are simply signs that your internal machinery lately had been used by vic- is not running right -that REPAIRS ARE tim. As he sat at the desk his back was NEEDED--fresh blood, new and vigorous .body to the window, which had been closed. and brain tissues. It isn't the discomforts you rvice "Well," he mused, "how was this man suffer from such chronic ailments that is important; it's the serious internal condition that killed? If this chair could only talk. they indicate. Heed those warnings of Nature. Suppose I was across the street in another Make the needed repairs before it is too late. You will be well building. Ah ! Say I'm an old whaler. never and strong and capable until you do. You will get worse -each day - I have a harpoon and a coil of rope. The until the final collapse or breakdown comes. ool window is open in this office. That broad That is the Law of Nature. There's no dodging back is a fine target -. Bill, look out or getting away from the penalty she exacts when her warnings are not considered. I N C. that window and see if I couldn't do it." Send ten cents for I turned to Fenner, and in my most Make Yourself Fit descriptive catalogue sarcastic tones I said: "You could, Joe, You can do It, if you will only make up your if you had an educated harpoon. After mind to get out of the way of putting the matter 900 -902 Penna. Ave., N. W. Washington, D. C. you threw it, it would pause cannily in off "until tomorrow" and begin at once to Build mid -air, at an angle of forty -five Up yourself. Nature has implanted in every turn human organism a wonderful revivifying, re- degrees, leap agiley up about six stories, vitalizing force, which she will exert to the ut- Loose , Couplers make another forty -five degree turn, slide most when you learn her methods and observe Combination Loose Coup. gracefully thru the window, and -." her laws. Patent medicines won't put you lee Puts and accessories. But Fenner was on his feet and beside right. Druggist's dope won't do you any good. Send 3c stamp for lit, me. His face was grave, but his eyes Let Me Show You Na'ure's Way Arnold erasure which is sure twinkled. "Sufficient, William," he said, I have spent my life studying Nature's methods of to interest you. building up and revitalizing wornout. broken -down "your sarcasm is excellent, but I'm too humanity. lier laws are fixed, immutable, absolute. 20Established2082 Lexington Av. N.Y. operating for every individual aline. I. KNOW what J. F. ARNOLD 1910 busy to listen to the rest of it. Let's have they can and will do for YOU, through my own ex- those field perience and that of thousands of my pupils, who came glasses." to me weak, ailing. discouraged, and are now strong. Ten minutes past. I began to grow well, able, ambitious men and women. It makes no difference what your present condition is: it makes no fidgety, when he suddenly handed the difference whether or not it was caused by your own CATALOG J. glasses to me. "Bill," he said, "do you see early indiscretions or excesses. Let me show you the straight, sure path back to health and strength and Contains 24 pages of reliable apparatus, that building out there -the one that ap- happiness. It's Nature's way, and there's no more pears to be as high as this one ?" doubt about the operations of Nature in the human standardized parts and raw materials. Com- frame than there is of the daily rising and setting plete line switch points, knobs, switches, "I do," I replied. "That could only be of the sun. rod, aerial wire, etc. the Yeakle. It and the Atwood are the Send for My Free Book Send 5c In for your copy two tallest buildings we have." stamps today. It will tell you all about Strongfortism. the Science Shotten Radio Mfg. Co.. P. 0. Box 3, Scranton. Pa. "Well, look it over carefully, and tell of gaining and maintaining vitality and vigor in Na- me if you make out a clothes line on the ture's way-NOT through any iron -clad courses of muscle -tiring exercises. starvation diets or any other roof." fanciful fads -but by Living Life as Nature meant it I gazed. At first I didn't see one, but to be lived, and thereby getting the greatest enjoyment out of lt. Write now for a copy of P -omot on and Universal Radio System presently I located it. I told Fenner that Conservation of Health, Strength and Mental Energy." Don't put off sending for it. IT'S FREE, but it's Up to the minute radio apparatus for pro- there was undoubtedly a clothes line there. worth good money to you, as you will see when you gressive users who can recognize quality. "So I thought," he said, absently. "Well have read it. Fill out the coupon below and enclose it with three 2c stamps to cover packing and postage Send stamp for catalogue. -let's call Davidson over here. It's up and I will mail you a special letter with the book on to him now." the subject you are most interested in. Universal Radio Mfg. Corp. I stared amazed. "Up to him," I par- Dept. W Elmira, N. Y. roted. "What's up to him ?" LIONEL STRONGFORT "The arrest of the murderer," said Fen- Physical and Health Specialist impatiently. to the ner, rather "You're on 1240 Strongfort Institcute, Newark, N. J. thing, aren't you ?" LEARN WIRELESS "Do you mean that you know who -CUT OUT AND MAIL THIS COUPON- - s At the OLDEST, LARGEST and BEST EQUIPPED Mr. Lionel Strongfort, Newark, N. d. school of its kind in New England. Positions guar- killed Corey ?" I asked, excitedly, as Fen- Dear Strongfort:- Please send me your book, "Promo, anteed. Thousands of satisfied graduates all over the ner reached for the telephone. Non and Conservation of Health. St ennth and Mental world. Splendid opportunities now in the Merchant Energy," for postage of which I enclose three 2c stamps to Marine. Day and Evening classes. Start any Monday. He paused with his hand on the re- cover nailing expenses. I have marked (x) before the EASTERN RADIO INSTITUTE ceiver. "No, I don't. But I know what subject in which I am interested. (12401 ....Colds ....Deformity ....Weak Eyes 899 Boylston St. Boston, Mass. he was killed with-and Davidson will ....Catarrh ....Insomnia _Falling Hair find out the rest." ....Asthma ....Heartweakness ...Poor Memory ....Obesity ....Short Wind ...Rheumatism "Well," I demanded, "what was he ....Headache ,...Flat Feet ...Poor Circulation ....Thinness ....Constipation ... Sk In Disorders Raw Mate- killed with ?" ....Rupture ....Biliousness ...Despondency WIRELESS rials,Apparatus, Fenner called a number into the 'phone ....Neuritis ....Torpid Liver ... Reend Shoulders experimenters needs, novelties listed and gave me a sweet smile over his shoul- ....Neuralgia .... IndWeston . Lung Troubles t- in our Catalogue C -3. Assure yourself of ....Flat Chest ....Nervousness ...Increased Height prompt service and right prices by buying from der as he waited. "That chunk of clothes this world famed, reliable, Experimenters' Sup- line, and -" he grew exceedingly sar- NAME ply House. 99 of every hundred orders re- castic, "an educated harpoon." ceived shipped within 24 hours. Catalogue C -3 AGE OCCUPATION FREE on request. Nor would he say more until Davidson. STREET THE NEWMAN -STERN CO., Cleveland, O. with Frank at his heels, burst into the room seething with excitement. CITY STATE You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 338 ELECTRICAL EXPERIMENTER April, 1920

NNNEDNNN111110O1111440NNNNNNN111; "What's this, Joe," panted the Chief. "Find something? Got anything ?" Joe leaned back in his chair, and I saw The Second Edition of that he was enjoying himself immensely. the 1 "Yes, Chief," he said, cheerfully, "I know what Corey was killed with." The Chief darted a fiery glance at Frank. Consolidated Radio "Find it in here some place, did you ?" he barked. "No," I could positively feel Frank's relief, "but I know what it was done with." Call Book "Damn," exploded the Chief. "So do I. It was a knife, but where "Oh, no, it wasn't," smiled-" Fenner. "It Has Been Unavoidably Delayed was a harpoon." The Chief's lower jaw sagged and Frank darted to the window. Then he turned owing to the vast amount of work back listlessly to Joe. "Come again, Fen- ner," he said. "It can't be done." involved in bringing it right up to "Not from those buildings below very date and in compiling the big handy," admitted Joe, "but this harpoon came from the Yeakle." amateur section that will be a The Chief laughed shortly. "That's a special feature. We urge all those poor joke, Joe," he snapt. "The Yeakle who is a good quarter of a mile away." have placed their orders to Fenner laughed. "Yes, but this was an be patient -you'll be glad you educated harpoon," he said. The detective Frank gave a sudden start. waited . when you receive your "I get you, Fenner," he yelled, and he was copy, which will be very soon. in motion while he spoke. "And I'll get him and bring him here." "Hey," yelled the Chief, "What -" The Consolidated Radio Call Book is But a slamming door was the only an- the only book in print officially listing swer. Frank was gone. Davidson turned to Fenner. "What kind all the radio calls as issued by the Bureau of Commerce. of a game is this ?" he demanded. "You're Every vessel and land station in the world is represented a pair of crazy asses, you and Frank. Now tell me what you're up to." and listed alphabetically, according to names of vessels "Bright boy, Frank," observed Fenner, or land stations, and according to call letters; Revision "it didn't take him long to tumble, once he got the tip. Now sit down and wait of American coastal stations under U. S. Naval control, until he gets back." and their new calls. For a half hour we waited in silence. Fenner smoked nonchalantly and refused to talk. The Chief fumed and paced the room. "A waste of time," he muttered All Amateur Calls Also Listed again and again. The minutes dragged by. And then the door opened and Frank pusht into our presence a swarthy little man with waxt mustaches and a decidedly SPECIAL foreign air. He was handcuffed. Two uni- Given formed policemen came behind, bearing a Free with Each Copy long wooden box, which they placed on A Wireless Map of the World in colors is given absolutely the desk. "Here's the bird, Chief," chortled free with each copy. This map shows the locations of all Frank ; "Fenner you're a dandy." the high powered RADIO stations in the world, including The Chief and I stared. "Sure you got the time signal stations. In addition it tells at a glance how the right man ?" he demanded. Then to far the prisoner, "What have you got to say? away any of these stations are. Of greater interest are Remember, it may be used against you." the time zones, which enable the amateur to compute instantly "There is nothing to say," said the the correct time for the zone in which he is located from any prisoner, in perfect English, "except that time signal station. I killed Corey-" "You confess ?" yelled the Chief. The man shrugged hopelessly. "Con- fess!" he echoed, "what else is there to do? I suppose you want to know why. Price $1.00 Prepaid Well, because Corey ruined me financially. Either Direct from us or for sale by He stole my purse; I stole his life. But I'd like to know how you picked up the the following responsible Dealers: trail." American Electro Technical Appliance Co. Nola Radio Co. 235 Fulton St., New York, N. Y. 134 Chartres St., New Orleans, La. Fenner stept over to the unfortunate Atlantic Radio Co. Newman -Stern Co. man. 34 Batterymarch St., Boston, Mass. 1874 E. 6th St., Cleveland, Ohio "I found it," he said, simply. "Why L. Bamberger & Co. National Radio Supply Co. didn't you keep that clothes line of yours Newark, N. J. 1405 U St. N. W., Washington. D. C. Cutting & Washington Co. Pioneer Electric Co. indoors ?" 6 West 48th St., New York City. E. 5th St., St. Paul, Minn. L. W. Cleveland Co. James137W. Poole, Inc. The man started, paled, then cried in 441 Congress St., Portland, Me. 16 Columbia St., Boston, Mass. anguish, "My God, I never thought of that. J. H. Bunnell & Co. F. D. Pitts Co. 32 Park Place. New York City 12 Park Square, Boston, Mass. I could have, couldn't I ?" Doubleday Rill Electric Co. Precision Equipment Co. 719 Liberty Ave., Pittsburg, Pa. "You could," Lester I. Jenkins 2437 Gilbert Ave., Cincinnati, Ohio agreed Fenner, grimly, 923 Purchase St., New Bedford. Mass. Radio Distributing Co. "and if you had, you never would have A. T. Hovey 4 West Park St., Newark, N. J. been caught. 61 Belvidere St., Boston, Masa. Reuter Electric Co. Send him over, Chief, and Hlaus Radio Apparatus 34 E. 6th St., Cincinnati, Ohio I'll tell you how the trick was done." Eureka, Ill. Radio Equipment Co. Manhattan Electrical Supply Co. 630 Washington St., Boston, Maas. The man departed in charge of the two 17 Park Place, New York City Southern Electrical Co. 114 S. Wells St.. Chicago, Ill. 3d and E Sts., San Diego, Cal. officers and Fenner tore the lid ,off the McCarthy Bros. & Ford H. E. Williamson Electric Co. wooden box which the officers had brought. 75 W. Mohawk St., Buffalo, N. Y. 316 Union St., Seattle, Wash. E. P. Noll. & Co. Jos. M. Zamoiski Co. He turned to me. "And here, Bill," he 21 N. 7th St., Philadelphia, Pa. Baltimore, Md. said, mockingly, "is your educated har- Published by poon." And he placed before my astonished eyes Consolidated Radio Call Book Co., Inc. an educated harpoon in very truth. It was 41 Park Row, New York City a small airplane, wirelessly controlled, and its nose was a long, bayonet -like knife. 411114111641,01NOIS "Then the clothes line -" You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1339

"Was his aerial," cut in Joe, "and for the distance over which he wanted to work he might just as well kept it inside. Just Mechanical INVESTMENT look this thing over carefully, old man." It's a shame that fellow stooped to mur- Engineering is a magazine that is teaching der. He has ideas worked out here that thousands cf people how to would have retrieved his fallen fortunes. make a profit on listed stocks Notice that the airplane attachment is and bonds. Write for this week's really two complete planes. I've been won- issue, which contains up -to -date in. dering ever since I realized how the job formation about several established was done; how under the sun, after the securities that can be bought now to yield a liberal return. INVESTMENT knife was buried in Corey's back, it was IS FREE. WRITE TODAY. gotten out again. Now I sec. When it came thru that window the wings were KRIEBEL ¿CO. right back of the propeller and the knife INVETTMENT BANKER,. and the rudder were in the rear. Now 141W South La Salle St.-Chicago notice the hinging arrangement whi_h folded those wings into a rudder and opened the rudder out into a complete sct of wings. The whole machine was re- versed. Even an aux;liary propeller has been provided. And the lag of the knife in the wound held the whole thing like a Learn at Home! IT brake just long enough for the propeller ORDER to get up speed before it gave and re- Employers everywhere are looking for men leased the machine. At that the fellow with mechanical ability. Splendid salaries TO -DAY must have had an anxious minute until and rapid advancement are offered. he got the contrivance out thru the win- There is an easy, delightful way in which See page 1235 dow again. Only the fact that this is a you can learn right at home in spare time. large room allowed h:m to get the ma- For 28 years the International Correspond- chine high enough to clear that window ence Schools have been giving men and sill on its way out. The selective control women just the training they need for offers nothing .new. The control points success in mechanical engineering and more are constantly traversed by a revolving, than 200 other subjects. Hundreds of thou- clock -work driven switch, and these minia- sands have stepped into good positions Lg1ÂRII EMGIMEERIMG ture vari- colored lights were the toll -talcs through I. C. S. help, but never were oppor- that told the distant pilot on what contact tunities so great as now. given minute. Expert electrical engineers are being paid fabulous salaries point the blade rested at any Let the I. C. S. help you. Choose the work -thousands needed today. We give you personal and For instance, when the light showed red, like best in the coupon below, then mark thorough training- practical, technical courses 3 months you to 2 years under expert engineers in electricity, steam, the rudder could be swung to the right; and mail it today. This doesn't obligate you gas, auto. armature winding, drafting, etc. Extensive la- left. He followed in the least and it will bring you information boratory and shop equipment. Not a trade school. Train- when on green to the that will start you on a successful career. This ing is condensed -if your time is limited, come to the its course thru powerful night glasses. is your chance. Don't let it slip by. Mark and Finlay Engineering College -only one of its kind in the West. Day and night sessions -enroll anytime. Write for Take a look at this coherer. You never mail this coupon now. FREE catalog, a post card will do. saw the like before. I'll bet it's a peach. - - -- -..raan our HERE - - -- FINLAY ENGINEERING COLLEGE And this relay's weight or rather, lack of INTERNATIONAL CORRESPONDENCE SCHOOLS 1003 Indiana Ave. Kansas City, Mo it, would amaze you. But the masterpiece BOX 6229, SCRANTON, PA. of the whole thing is the power plant. He Explain, without obligating me, how I can quality for the MATHEMATICS MADE EASY must have worked for months on this position, or In the subject, before which I mark X. The Arcascope -the Combination Triangle Brain a model gasoline engine. I can imagine that ELECTRICAL ENGINEER CHEMICAL ENGINEER with a -will multiply. divide, figure --` Electrician SALESMANSHIP percentage and proportion, solve all problems for its weight it produces an awful power, Electric Wiring ADVERTISING MAN in irigonometry and geometry, draw symmetri- Electric Lighting Window Trimmer cal figures. plot arcs, etc. Superior to any slide w and it is absolutely silenced. Electric Car Running Show Cord Writer rule. Simple to operate. Also i n c l u d e s a ,,rj Heavy Electric Traction Outdoor Sign Painter TRANSPARENT TRIANGLE, PROTRACTOR and "There are at least a dozen new ideas Electrical Draftsman RAILROADER THREE RULES. Used at Columbia University. involved here, and new applications of Electric Machine Designer ILLUSTRATOR West Point, U. S. Aeronautic Schools, etc. Only 85 Telegraph Expert DESIGNER cents Postpaid. Order today before you forget. hundreds of old ones. Under the spur of Practical Telephony BUSINESS MANAGEMENT Dept. J, L. J. LEISHMAN CO., Ogden, Utah man MECHANICAL ENGINEER Private Secretary a great emotion - REVENGE -this Mechanical Draftsman BOOKKEEPER has produced a thing of terrible possibili- Ship Draftsman Stenographer and Typist Machine Shop Practice Cere. Pub, Accountant ties. You have seen what happened to Toolmaker Traffic Management Corey." Gas Engineer Commercial Law SELENIUM CELLS CIVIL ENGINEER GOOD ENGLISH Made by entirely new process. Highly sen- The Chief and I were gazing in awe at Surveying and Mapping STATIONARY ENGINEER sitive and quick- acting. Suitable for all ex- I MINE N'OREM`N OR ENGR CIVIL SERVICE periments. From $5 up. the little plane. appreciated the disposi- Mail Clerk tion of wing surface which cut down the Arehiteetoral Draftsman Textile Overseer er Supt. Write for Catalog PLUMBING AND HEATING AGRIOULTUItE Spanish span sufficiently to allow it to pass thru a Sheet Metal Worker PaaltryRalsing French Selenium Laboratories window three feet in width. And I re- Navigator Automobile. Italian Good Ground, Long Island, N. Y. alized the ratient paring away of a fraction of an ounce there that brought the total Name T -tie -ta weight of the machine low enough to allow Present Fun, Magic and Mystery! of the small supporting surface. There Occupation 56 Feats in Magic, 250 New Jokes, 21 Puzzles, 1 was not an unessential piece of material . Street Fortune Telling Tablet, 52 Money -Making Secrets, to be found on the plane. The only thing and No. 15 Card Tricks, 71 Toasts, 58 Verses in Comic Poetry, 10 Funny Readings, 41 Epitaphs, and 11 not needed in the operation of the thing City State Parlor Pastimes. You get all the above -mentioned was the knife, and even it had been ground and our big illustrated Catalog of 125 Magic Tricks down until it was little more than a very for only 10 cents. Write today. thick needle along its length, with a large DETROIT TRICK & NOVELTY CO. cutting surface at its point. 454 -456 Dix Avenue Detroit, Mich. The Chief finally broke the silence. "I think," he said, "that the educated harpoon is too dangerous a contrivance to survive. Science may need a lot of -these STAMMERIf you stammer attend no stammering school till you get my big new FREE book and special rate. Largest and do- funny things on it, but it will have to most successful school in the world curing all forms of de- worry along without them. The details fective speech by advanced natural method. Write todsv North -Western School for Stammerers, Inc., 2331 Grand will not be made public, and just as soon Ave.. Milwaukee, Wis. as that man is convicted I'm going to per- WANTED -Railway Mail Clerks MAKE PEOPLE LIKE YOU sonally destroy it." STUDY get along better, make more money. Fenner nodded thoughtfully. "Yes," he a winning personality, learn to $1300 First Year -FRANKLIN - INSTITUTE HUMANdevelopknow people as they are. Send shame it, cents (stamps) for Personal Power," agreed, "it's a to do but God Dept. R101 Rochester, N.Y. a little book that the way. help us all if its constructional features Hundred Men- me, without NATURE points S Sus Send Address. Progress League, 2931 Union Sq., New York. Women Needed charge (1) sample of Spring become known." O Banway Man Clerk Exami- nation questions; (2) sched- He lifted it tenderly and placed it in the ule showing places of all U. SPEED LATHES, wooden box. With the lid in his hand he Life Job. Pull `O S. Governmentnt coming oxaml- GASOLINE ENGINE CASTINGS paused, looking down. His eyes shown Unnecessary. etnment lobs open to men and with the love of an enthusiast for the deli- women and (4) free book deecrib- M. & J. Specialty Co., 252 South Parke St., s Ina them. Pontiac, Michigan cate, wicked, creation. "Good -bye, Edu- Name cated Harpoon," he breathed. Address You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1340 ELECTRICAL EXPERIMENTER April, 1920

,,11 - 1 Opportunity Ad -lets YOU will find many remarkable opportunities and real bargains in these columns. It will pay you to read and investigate the offerings made every month by reliable firms, dealers and amateurs from all over the country. No matter what you may be seeking, whether supplies, automobile accessories, the opportunity to make money, or anything else, you will find listed here the best and most attractive specials of the month. Advert.scinenis in this section nine cents a word for each insertion. No advertisements for less than 75c accepted. Name and address must be included at the above rate. Cash should accompany all classified advertisements unless placed by an accredited advertising agency. Ten per cent discount for 6 issues, 20 per cent discount for 12 issues. Objectionable or misleading advertisements not accepted. Advertisements for the June issue must reach us not later than April 28. The Circulation of the Experimenter is over 150,000 and climbing every month EXPERIMENTER PUBLISHING CO., INC., 233 Fulton Street, New York, N. Y.

Auto Accessories. American Made Toys. Blueprints. Wanted -Good live selling agents for our We Gff,r an Opportunity to manufacturer with Blueprints. garage Learn blueprint reading. From 33 testing instruments and publications. facilities for large production, also to homework - large Blueprints. It matters not what line you Write for catalogue and particulars. H. E. ers on smaller scale, to manufacture Metal Toys are in. We show you Phillips & Company, how. It's easy. It's job Service Division, Union and Novelties. Unlimited field and enormous insurance. Get out circular -or send $t. We City, Ind. business open for ambitious people. No experi- will mail you first four Blueprints. If satisfac- Fords run 34 miles per gallon with our igzo ence required. No tools needed. Our casting- tory order the balance. Chas. J. H. Freeth, carburetors. Use cheapest gasoline or half kero- forms turn out goods complete. Since the differ- Consulting Chief Draftsman, Mechanic Improve- sene. Start easy any weather. Increased power. ent Toy Expositions, manufacturers are covered ments Association, Dept. 24, 1628 W. Lehigh Styles for all Motors. Runs slow in high gear. with orders until December. You can enter this Ave., Philadelphia, Pa. Attach yourself. Big profits for agents. Money field now, by manufacturing `American Made back Toys." We furnish castingforms for Toy Sol- guarantee. 3o days' trial. Air - Friction Chemicals. Carburetor Co., 27o Madison diers, Army, Navy, Marine Cannons, Machine Ave., Dayton, Ohio. Guns, Indians, Cowboys, Warships and other Four Dollars Insures You for life against be- novelties. Castingform , complete outfit, $3.0o Experimenters, are you interested in novel, ing kicked cranking your Ford. Write today up. We buy these goods, direct from manufac- chemical experiments? Send toe for large col- for free booklet "KANT- KICK." The Safety turers. Yearly contract orders placed with re- lection. Merel Sager, 44 Apple St., Tiffin, Device for liable parties. We Ohio. Cars. Easily attached. Buffum Tool pay very high prices for Newest, Chemical, Novelty. Send tsc. Walter Co., Louisiana, Mo. clean painted goods. Samples furnished. "Bird- Hunter, Whistles," great seller, just added to our stock Swedesboro, N. J. Miracle Motor -Gas amazes motorists. 3c worth list. Booklet, Information, Instruction free, if 20 Different Chemicals, 75e. is different chem- equals gallon gasoline. Eliminates carbon. you mean work and business. No others in- icals, soc. (No stamps accepted.) Leslie Evans, 300% profit. Isom, Idaho, wires: "Ship soo pack- vited to write. Toy Soldier Manufacturing Co., Box 86, Audubon, N. J. ages. Made $70 yesterday." Investigate. Chas. 32 Union Square, New York. Microscopes, Chemicals, apparatus, labora- K. Butler, Co., Toledo, Ohio. OUNNIMMIPo MEW Will1001.111101110NIMIN tories! Everything for the experimenter. Send Battery Charging pays big profits. City cur- for price list. Radio Chemical Supply Co., 915 rent or gas engine operates. Easy terms. Ho- Novelties. Westcott St., Syracuse, N. Y. barts, Troy, Ohio. Big Trick and novelty catalog free. United Auto Motors and Supplies. Buick, Hupp, Sales Co., Springfield, Ill. Photo Developing. Franklin, Michigan, Everett, Hudson, Chalmers. Both water and air -cooled $4o.00 "New" Magazine Bead Necklacrs. $i.5o, post - motors, each paid. All colors. The Oddity Centre, 6o Vine Mail us 15e. with any size film for development and up. Bosch Magnetos, $x .00 each and up. St., Wyandotte, Mich. and six velvet prints. Or send six negatives any Presto Tanks, $5.00. Coils, Carburetors, Head size and isc. for six prints. Or send 25c, for one Lamps, Horns, Air Compressors, Generators, 8 x io mounted enlargement. Prompt, perfect Starters. Write for bargain bulletin second hand Office Devices. service. Roanoke Photo Finishing Co., 255 Bell auto accessories. Johnston, West End, Pitts- Ave., Roanoke, Va. burgh, Pa. Multigraphs, Addressographs, Duplicators, Tires -Direct to you prices. Exclusive repre- Sealers, Folders. Less than half price. Guar- Clean, Neat, Perfect Kodak Finishing at the sentatives wanted each locality to use and sell anteed one year. Pruitt Company, i1z -C North lowest prices. Work returned the same day re- Mellinger Extra Ply Tires. Guarantee Bond La Salle, Chicago. ceived. Send film for sample print and copy of 8,000 Miles. Sample Sections furnished. Mel- Addressographs, Multigraphs, Duplicators, catalogue on developing, printing, enlarging and linger Tire g8o hand coloring, also copy of Photo Craft Maga- Company, Oak, Kansas City, Mis- Folders, Sealers Bought, Sold. Guarantee. Of- zine, which souri. fice Device Company, i56 -X North La Salle, Chi- will help you make better pictures. cago. Photo Craft Co., Box 69, Ann Arbor, Mich. Power increased, carbon eliminated; results -11111111=1111111111111111 guaranteed. Write for booklet. No-Leak-0 Pis- 01101111111111101101011 ton Ring Co., Baltimore, Md. Phonographs. Dancing Instruction. Save -All Carburetor Attachment makes Fords Build your own phonographs and manufacture Learn Fox -Trot, Waltz, Two -Step and One - run better. Gives more miles, power and speed. them for profit. Drawing, Instructions, Parts Step in your own home by wonderful Peak Sys- Free trial. Savall Company, 3716 North Clark Price List, Blue Print, etc., complete, sent free tern of Mail Instruction. Thousands taught suc- Street, Chicago. upon request. Write today. Associated 110111111111=11M111. Phono- cessfully. No music needed. Wriee for free graph Co., Dept. E t, Cincinnati. information. William Chandler Peak, M. B., Aeronautics. Room 23i, 821 Crescent Place, Chicago. Make Your Own Phonograph. Particulars free. SZYMEMINCII11. DeSeIO-PhonE, P. O. Box 720, Attica, Indiana. Flying School. We teach you to fly. Lowest Electrical Supplies and Build Your Phonograph. "Perfection" high - Appliances. rates consistent with the service we render. quality spring and electric motors, tone arms, New classes always forming. Philadelphia Aero- reproducers. Wonderful Battery Charging pays big profits with HB Service Corporation, 636 Real Estate Trust Build- results. Big saving. ing, Philadelphia. New catalog and building instructions mailed Equipment. Electric Light Generators and for to cents. Indiana Phonograph Supply Co., Motors can also be furnished on easy payments. 100 Model Aeroplanes. Good flyers. 15e Indianapolis, Ind. Full information free. Hobart Brothers, Troy, brings Ohl working Drawings and Prices. F. Bruland, Red- Build Phonographs -Reliable Dayton Motors, ford, Mich. Tone Arms, Hardware and Accessories. Illus- StoragD Batteries. Learn to make them for Scout Airplane all metal, Military model. trated Catalogue for two cent stamp. Sam R. Automobiles; we furnish everything. Sample Complete with wheels and propellor. A Kremer, 118 Court Ave., Dayton, Ohio. plates, 4oc. Windsor Specialty Co., 541g Wind- beauty; sor Ave., Chicago, Ill. so cents postpaid. Immediate delivery. Ameri- Build your own phonograph. Other companies can Airplane Works, Chevy Chase, Md. sell parts. We Small Induction Motor castings and punchings. show how to make them. Plans Robert Orn:thopter and gravit3 flyer with warping and oe. Wright, 54i Commercial Ave., Superior, Vondrau, Preston, On.., Canada. adjustable wings 16"x22 ". Durable and scientific. Ncbr. Inventors: Models, Dies, Tools, 28 years' The only successful flapping flyer made. Price, experience, work guaranteed, lowest price. Man- $t.00 Adams Aeroplane Co., 252 West 83rd St., Postcards and Pictures. ufacturing of specialties our hobby. Peerless ïI Y. Die & Tool Co., 121 Opera Pl. D. B., Cincinnati, Ohio. Blue Jay Monoplane. Build it yourself. 3500 Classy Pictures -Do you like real "snappy" feet altitude with motorcycle engine. Complete pictures? Boys, these are all nifty pocket size Mansfield's Automatic Water and Oil Finder a plans $5.00. Send stamp for full information. pictures and we know you will like them. Make proved success, silver medal awarded. Partic- Mitchison Bros., Baltimore, Md. fine den decorations. Send for a set today. ulars from Edwin A. Mansfield & Co., 94 Victoria Prices, $i.00 per dozen; set of 3o for $2.00. Fifty Road, New Brighton, England. for $3.00. Two samples, 25c. United Sales Co., Motorcycles. Springfield, Ill. Blueprints -Motor connections. 236 A.C. Single, two, and three phase, including voltage, cycle, Bargains in Rebuilt Motorcycles. Lowest prices. Girls in bathing costume, 15 beautiful postcard phase, speed changing. 123 D. C. diagrams. Shows Indians, Excelsiors, Barleys. Overhauled. Test- size photographs $x, or ten 5x7 for $1. Sample of voltage changing, testing, etc. izo Transformer ed by experts. Guaranteed. Shipped subject to each 25C. Money refunded if dissatisfied. A. diagrams. Single, two, and three phase. 170 inspection. Write for big free list. We furnish D. Tinklepaugh, 340 5th Ave. So., Minneapolis, rheostats, controllers, compensators, automatic Bank References. Floyd Clymer, Desk E. Minn. starters, and voltage regulating devices, with "Largest Motorcycle Dealer in Western Amer- both internal and external connections. so Sam- ica," Denver, Colorado. Rare Real Photos. Bathing beauties, models, ples A. C. 25c. Particulars free. Charles Chitten- the right kind. We are reliable. Samples 25c den, Dept. A, 3024 Matthews Avenue, Kansas coin. Artiste, Auburn, Ind. Scenery For Hire. City, Missouri. High Art Subjects. Beautiful models in clas- Welding Instructions for operating Oxy :Acety- sic poses. Send toc for illustrated Collapsible miniature lene apparatus on all metals; sent postpaid fifty, Scenery for all plays. Decorations. reference sheet and price list. United Sales Co., cents. Address E. E. Bertschy, Cedar Rapids, Amelia Grain, Philadelphia. Springfield, Ill. Iowa. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers April, 1920 ELECTRICAL EXPERIMENTER 1341

Agents Wanted. Business Opportunities. For Advertisers. Traveling Men, Women -Best side line in the You Can Earn $5o to $150 weekly writing ad- 24 Words in loo Syndicate Magazines, $1.0o; world; nothing to sell; information only. J. H. vertisements. Experience unnecessary. Particu- inch display, $4.00. Lists free. Stanford Adver- Walker, Boulder, lars for stamp. R. P. Koehler, 156 West Vernon, tising Co., Pittsburgh. Colo. Los Angeles. Agents. Sell raincoats, gabardines, leather - Attention compelling, order coaxing letters, ettes. We deliver and collect. No advance pay- You can Earn over thirty dollars weekly work- circulars, $3. Mailpress, Swift Bldg., Cincinnati. ments. Sample coat free. Largest commissions. ing spare time for us. H. E. Phillips & Com- Money? Jacobus Art Ads make small space Temple Raincoat Co., Box 9, Templeton, Mass. pany, Service Division, Union City, Ind. pay big dividends. Price $s.00. Write today. 4 Your Opportunity. Get in business for your- Free Intormat.on gladly sent regarding large Jacobus Service, 1073 Sanford Ave., Irvington, self; mail order or local; manufacture your own earnings made Raising Canaries. Instructive, New erse . products; employ other agents; everything fascinating Pastime. No capital required. Bird given clearly in our big magazine of plans, Farm, Lynnhaven, Virginia. Formulas. schemes and ideas. Three months, 25e.; sample Young Men to S.11 Our Card Specialties. Eas- 1,000 Formulas, 25e. Luminous paint- Resilver- copy, toc. Special Service, 42i Shannon Bldg., iest selling novelties in the world. Outfit Free. ing mirrors- Renewing dry batteries- Mechanics' Pittsburgh, Pa. John W. Burt, Coshocton, Ohio. soap -Carbon remover -Gas tonic-Puncture plug- Science creates new auto wonder. Solves puz- 3,384 Moneymaking Plans. Formulas. Trade - ger-20C each. Entire collection, Soc. Satisfaction zling problem; no more rain or snow -blurred Secrets. "Encyclopedia Business Opportunities." guaranteed. Ideal Book Shop, 5501 -EF North windshields; Mystic Cloth, works like magic; 3 volumes $1. Ideal Book Shop, 5501 -EV North Robey, Chicago. deposits invisible chemical film; one rub keeps Robey, Chicago. Million Tested Formulas, Trade Secrets, Proc- glass clear 24 hours; one agent sold 5,000. Se- Dollars Yearly in Your Back Yard. No gin- esses. Everything) Thousand pages. Cost? curity Mfg. Co., Dept. 242, Toledo, Ohio. Only $2.00. Postpaid. Can I find it? Yes; and seng, mushroom dope. New ideas. Investigate. 999,999 others. Write us. L. Goodnow, Highland Wanted. Agents to call on garages and ser- Particulars free. Metz, 313 East 89, New York. vice stations. Best line of testing instruments Ave., South Sudbury, Mass. publications on the market. Complete cata- Money -Talks Magazine. Published for progres- 1,000,000 Formulas. Processes. Trade secrets and sive men. Send for sample copy. 70 -B Park logue. H. E. Phillips & Company, Service Di- New for every business. 1016 pages, $2. Ideal Book vision, Union City, Ind. Place, Newark, Jersey. Shop, 55o1 -EE North Robey, Chicago. Beginners -Complete Mail Order System. C., Patents for Sale. To sell, buy or obtain pat- Here's a "Hummer"- Valuable Veterinary For- Box ioo5, Atlantic City. ents write Patent News, 309, Washington, D. C. mulas, for the treatment of Mange, Distemper, Men and Women make big daily cash profits $1 Do_s It. Texas oil land making holders big Fits, Worms, Canker and Paralysis in dogs. As in handling our Patented Stick -On" Window money every day. Bank references furnished. prescribed by a specialist, $2.ao each, 6 for $io.00. Lock. Locks window when open for ventilation. Investigate us thoroughly, that's all we ask. Compounded at any drug store. Practical Spe- Stops rattling. Instantly attached or removed. Results count. Our plan $z down, balance cialty Co., New Haven, Connecticut, Box 1525. No screws or tools necessary. Prevents chil- monthly; ftw months gives you Warranty Deed dren from falling out of open window. Big de- to land. May pay profits $20o or more monthly. For the Hair mand; sells on demonstration; as many as one Maps, reports, established facts FREE. Address dozen to each home. Whole or part time. Mail Sourlake Texas Oil Co., 867 DeMenil, St. Louis, I Was Bald. Obtained hair growth by an In- toe for sample and proposition. Address Room Mo. dian's ointment containing genuine bear oil and 202, 147 Fourth Ave., New York City. S.gna -Start a business at home, something rare plant juices. Many others have had won- every store needs. Learn to make Glass and derful results. Fine for dandruff. Harmless. Agents. Big reurns, fast office seller; par- Electric Signs by our new easy process without Will send box, postpaid, with recipe, loc. John ticulars and samples free. One Dip Pen Co., la the use of 'brush. Big money, easy to learn. Hart Brittain, 15o E. 32d St., BB -3oo, New York. Daily Record Bldg., Baltimore, Md. First sign i.l pa cost of Earning. Morris 500 for Electric Sign & Mirror Co., Box 74, Westport Health Resorts. Agents wanted at once Mitchell's magic Kansas Mo. marvel washing compound; 300% profit, enor- Station, City, .'s oungborn ' Butler, N. J. Nature Cure Institu- mous repeater. Washes clothes spotlessly clean Substantial manufacturing corporation wants tion. All Physical Culture and drugless methods in to to 15 minutes; i,000 other uses in every capable men to establish branch and manage employed. Ideal resort for rest and regenera- home. Astounds and delights every woman. salesmen; $300 to $t, oo necessary. You handle tion.- Open all the year. Dr. Benedict Lust, Nothing else like it. Nature's mightiest cleanser. own money. Will allow expenses to Baltimore Butler, N. J. New York City office: American Contains no lye, lime, acid or wax. Free samples if you will qualify. For particulars address School of Naturopathy, 'io E. 41st Street, Pros- furnished to boost sales. We positively guaran- Secretary, 4i6 N. Howard St., Baltimore, Md. pectus free. Explanatory literature, 25s. tee the sale of every package. Exclusive terri- Enter a new business. Earn $3,000 to $6,000 Dr. B. Lust, Florida Drugless Health Resort. tory. Own your own business. You cannot fail yearly in professional fees making and fitting a Wonderful results in stubborn cases. Best to make big money. Barber, Ohio, made $600 foot specialty, openings everywhere with all the equipped, best located, best conducted Nature last month. Send for free sample and proof. trade you can attend to; easily learned by any- hustle, chance. L. Mitchell & Cure Institution in the Sunny South. Open Oc- Hurry, grab this one at home in a few weeks at small expense; tober first to June first. Benedict Lust, N.D., Co., Desk 318, 1312 -1314 E. 6ist St., Chicago. no further capital required; no goods to buy; M.D., Tangerine, Fla. Agents -$40 -$100 we.k; free samples; gold sian job hunting, soliciting or agency. Address Ste- letters; anyone can put on store windows; big phenson Laboratory, 18 Back Bay, Boston, Mass. Health. liberal offer to general agents. Metallic demand; I Made $30 a We -k evenings with a small Mail Cigarette pipe or chewing habit conquered. Letter Co., 433-Z,, N. Clark, Chicago. Order Business. Home Free Booklet tells how. Guarantee Write for free brochure. Edw. J. Make and Sell Your Own Goods. Formulas by 2C postage. Alex Scott, Cohoes, N. Y. Woods, TB -3oo Station F, New York. Expert Chemists. Manufacturing Processes and Breed Canaries - Profitable pastime. Particulars At Last! Constipation Permanently Removed Trade Secrets. Write for formula Catalog. free. Bird Farm, Lynnhaven, Virginia. Nature's Way. No drugs, internal baths, exer- Chapin Mystic Company, Washington, D. C. cise or massage. Perfectly harmless. Easily Mexican Diamonds flash like genuine, fool ex- Help Wanted. made at home. Formula $1. B. White, 2310 Valentine Avenue, New perts, Stan,' tests, yet sell for 1 -50th the price. )fork. Few live Agents wanted to sell from handsome Detective s and lnvest:gators are in demand. Tobacco or Snuff Habit Cured or no pay; $1 sample case; big profits, pleasant work. Write Travel and earn big money. Learn this fascinat- if cured. Remedy sent on trial. Superba Co., today. Mexican Diamond Imptg. Co., Box Ft, ing profession by home study. Particulars free. SA, Baltimore, Md. Las Cruces, N. 'Alex. American School of Criminology, Dept. E, De- Pyorrhea. (Rigg's Disease- Bleeding or Swollen Wonderful Chance. Men's Shirts and Furnish- troit, Mich. Gums.) Hundreds have been helped by "Pyorem," ings at wholesale rates or make $io daily as Detectives Earn Big Money. Excellent oppor- the successful home treatment. Purifying, heal- agent starting real business. Goodell Co., 107 tunity. Particulars free. American Detective ing,. preventative. Full month's treatment, con- Duratex Bldg., New York. System, 1968 Broadway, New York. sisting of a very beneficial massage paste and an antiseptic tooth -cleaning paste to be used in $10 Daily refinishing chandeliers, brass beds, Be a M.rror Expert. $3 -io a day; spare time place of your ordinary dentifrice together with automobiles by new method, without capital or home at first; no capital; we train, start you full directions for treatment, $1 postpaid. Or, experience. Free particulars and proofs. Write making and silvering mirrors French method. write for free Booklet "E. " Pyorem Mfg. Co., today. Gunmetal Co., Avenue D, Decatur, Ill. Free Prospectus. W. R. Derr, Pres., 579 Decatur 439 Seventh Street, Brooklyn, New York. Street, Brooklyn, N. Y. Agents and Crew Managers new fast - selling Too Fat? Reduce weight easily, pleasantly, no food specialty. Livest article. Packed your $100 to $150 Month. Hundreds openings. U. S. self - starvation no strenuous exercise. Reliable, Government positions. Men -women, 18 up. Ex- guaranteed. Obtain Oil of Korein at any busy label. Write or wire. Federal Pure Food Co., free. 23o3-H Archer Ave., Chicago. perience unnecessary. List positions Write pharmacy or write for free brochure to Korein immediately. Franklin Institute, Dept. R -26, Co., NA -Boo, Sta. F., New York. Sign Lettcrs for windows at honest prices. Rochester, N. Y. Free -Stop using tobacco. We will give free Genuine gol I leaf. Chicago Sign System, G 326 Detectives Make Big Money. Travel, be your information how to conquer habit easily and River St., Chicago. own boss. Either sex. We instruct, small cost. permanently. Results guaranteed. Anti -Tobacco 350% Prot- Whirlwind seller; Klean -Rite. Write Johnson's Detective School, 232 Sheldon ¡Lune, Dept. C, Omaha, Nebr. Washes Clothes Quick without Rubbing. Sam- Ave., Grand Rapids, Michigan, Dept. A. ples free. Bosco, 3253 -Ed Bclleplainc, Chicago. Earn $25 Weekly, spare time, writing for news- For Men. papers, magazines. Experience unnecessary; de- Insyde Tyres, inner armor for automobile tires tails free. Press Syndicate, 5665 St. Louis, Mo. Books and Pictures- Catalog free. United double mileage and prevent punctures and blow- Sales Co., Springfield, DI. outs- quickly applied; cost little; demand tre- Wanted m n. Become Automobile Experts. mendous; profits unlimited. Details free. Ameri- $3$.00 week. Learn while earning. Franklin In- Send Us Your Dull Safety Razor Blades. We stitute, Dept. R -8o6, Rochester, N. Y. will re- sharpen them so they shave like new can Automobile Accessories Co., Dept. 54, Cin- blades for 3c each, any kind. Quick service. cinati, Ohio. Firemen, Brakemen, Baggagemen, $14o -$2oo Entire satisfaction guaranteed. Antiseptic astrin Wide -Awake Man to take charge of local Colored Porters by Railroads everywhere. Ex- gent pencil given free with every dollar order if our perience unnecessary. 897 Ry. Bureau, East St. trade. $4 to $5 a day, steady. No experience you mention "Electrical Experimenter." Send required; pay starts at once. Write today. Louis, Ill. your blades to -day. Keenedge Company, Inc., American Products Co., 1504 American Bldg., Dept. L, 184 Washington St., Chicago, Ill. Cincinnati, Ohio. Salesmen Wanted. Get Vital Strength. Retain youthful vigor. Wonderful results. Intensely interesting booklet free. Winslow H. Chase, Washington, D. C. Short Stories, Manuscripts, Wanted. Salesman-Side or Main line, to sell low priced 5,000 mile guaranteed tires. 3ox3 4 non -skid Detectives Earn Big Money. Travel. Great Short S;or:es, poems, plays, etc., are wanted sells for $11.95; other sizes in proportion. Good demand. Experience unnecessary. We train for publication. Literary Bureau, 165 Hannibal, money making proposition for live wires. Write, you. Write for free particulars. American De- 1968 Broadway, N. Missouri. Consolidated Tire Co., 6i6 So. Michigan, Chicago.s_. tective System, Y. Song Writers. For the Photographer. Musical Instruments. Violins. Deep, Mellow, Soulful on creel' If You Will Write -The words for a song I - Do for free sample Easy terms for wonderful instrument. Get will write the music and guarantee publisher's you take pictures? Write tails today. Gustav Henning, 231 nth acceptance. Poems on any subject acceptable. of our big magazine, showing how to make Miami. Florida. Etbwell Hanson, Room 131, 3808 Broadway, better pictures and earn money. American Pho- Chicago, Ill. tography, 465 Pope Building, Boston, Mass. (Continued on page 1342) Yost benefit by mentioning the "Electrical Experimenter" when writing to advertisers. 1342 ELECTRICAL EXPERIMENTER April, 1920

Books. Books -- Continued. Instruction-Continued.

World's Beet Book for Auto Mechanics. Covers Wireless Course in 20 Lessons. By S. Gems- Used Correspondence Courses. All kinds Elementary Electricity, Motor Car Electric back, A. Lescarboura and H. W. Secor, E. E. bought and sold. E. Moffett Ruston, Louisiana. Systems, The Gas Engine and Driving Cars. Tells you everything you want to know about Cartooning Comics and Lettering. Complete Nearly six hundred diagrams. Prepaid to you "Wireless" theory, practice and history. A Course only $5, postpaid. Over 300 illustrations. for $2.50. Order to -day. H. E. Phillips & Co., clear, concise course on evc.y .phas' of this Stamp brings easy lesson. Cartoonist Ernie, Service Division, Union City, Ind. subject. 160 pages -35o illustrations, 3o tables. E'yria, Ohio. Flexible cloth cover, 75c postpaid. Stiff cloth Books on Sex for Men and Women. Catalog cover $1.2 postpaid. Experimenter Publishing Study at Home: .Dentistry, chemistry, etc. Write Metropolitan College, Box 210, Station "A," free. United Sales Co., Springfield, Ill. Co., Book Dept., 233 Fulton St., New York City. Boston, Mass. "How to Thought Read." Mind Reading at any Distance, 2oc. "Hypnotic Suggestion" the Secret Exchange. Letter Specialists. of Success. 208 pages, i.00. Circulars free. Letters and Science Institute, E18i8 North Wells, Chicago. For Sale or Exchange -Electrical Apparatus, advertising matter so strenuous Musical Instruments, Cameras, etc. Write for and so injected with pulling power and pep they complete list can't fail to sell your goods. Nelson, um South Are Spiritist Seeing Things? or hoodooed- at once. F. J. Bretzke, Browns- Broad, Philadelphia, Pa. which? Read 119 -page booklet. Biblical exposé ville, Wis. and facts concerning strange spirit "phenome- Two Motors, wireless outfit, motorcycle wheels, Music. non." 15c post free. R. C. Polston, People's In- Oliver typewriter, tools, miscellaneous articles. formation Service, Omaha, Ill. Box 74. Box 255, North Bennington, Vermont. 12 Songs for $1. In order to popularize our Rare Instructive and Entertaining Books. Cy.le Incubator, $7. Harry C. Cooper, Park - great hit, "Desertland," retail price 3oc, for Catalog free. United Sales Co., Springfield, Ill. ton, Md. a short time we will offer it and eleven other popular song postpaid $r. Listen, My $17.00 hits Offer limited, Dear Reader. If Occult, New -Thought and Sci- Children takes my wireless send $1 today Sure. Riviera Music Company, entific books appeal to you, send for my catalog, outfit, $7.00 my aeroplane. Write Wallace Cut- Room i31 Chateau Theatre Bldg., Chicago, Ill. it's free. I have books on Personal Magnetism, ler, Franklin, N. H. Concentration, Spiritualism, Clairvoyance, Seer - Paint -Roof and iron, waterproof, stops leaks, Moving Picture Plays. ship, Will, Mind, Hypnotism, Mesmerism, Char- guaranteed five years; barrels, 70c gallon. Con- acter Reading, Healing, Mysticism, Success, tinental Co., 405 Lexington Ave., N. Y. Photoplays Wanted. Big prices paid. You can Salesmanship, Mechanics, Entertainments, etc. Sell. Swap No. 4 Victrola records, etc., $2o- write them. We show you how. Free particu- A. W. Martens, J -49, Burlington, Iowa. Worth Apparatus for Wireless; Details. Alfred lars. Rex Publishers, Box 175, E -12, Chicago. Embowitz, Washington, Depot, Book of Nature. By Dr. Faulkner. Plain facts Conn. Miscellaneous. about sex matters every man and woman, mar- For Sale. f4 H. P., im volt, D. C. Dynamo, ried or about to marry, should know. to cents. $36.00. Onyye pair Newy-Type phone, $i2.00. S. S. Clean Your Wall Paper, it's easy to do. New United Sales Co., Springfield, Ill. $5.00. process, no experience or apparatus required. World -Romic System. Masterkey to all lan- KMagnet oGeneratorr,,o$3.00. B. Flonacki, W. Complete copyright instructions, only one dollar. guages. Six textbooks, $i.44; French chart, 37c.; Superior Street, Chicago. James T. Herr, 2919 W. North Ave., Baltimore, Spanish, 37c.; aviation dictionary, $i.so; French - Wanted to buy a or 3" Spark Coil. Geo. F. Md. English aviation dictionary, 61e. Languages, Howell, Pasadena, California. Be Well, Strong, Happy, Successful. Drugs 143 W. 47th St., New York. For Sale -Used Mechanical Drawing Materials. and surgery unnecessary. Modernized Natural Books for Men. Also "classy" pictures. Cat- Leder, 1187 2nd Ave., New York, N. Y. Healing insures success also a profitable, philan- alog free. United Sales Co., Springfield, Ill. For Sale. Rotary Spark Gap, No. 2 Junior thropic and educational profession. Convincing Omnigraph, Remington 22 Repeater and Audio literature free. Science Institute, E -i818 N. Nature Laws married and engaged people Tron. Bud Hartmann, 73 Liberty St., Meriden, Wells, Chicago. should know, Soc. Central Company, for Ninth Conn. Shawnee, Oklahoma -a live city. Questions Ave., New York. Book lists free. 1 KW -E -Clapp Eastham transformer Key, Oil answered. Board of Commerce, Shawnee, Okla- The Abuse of the Marriage Rlation. For sin - transformer ribbon, Beck insulator, Condenser, homa. gle, engaged and married men and women. Switchboard switches, Kickback preventer and Popcorn for Home Popping, shelled, depend- Saves disappointment, prevents diseases, and Hot Wire Ammeter, all aparatus sets on back able, sent anywhere. Write for price card. Five makes happiness. Postpaid for seventeen 3 -cent of board. Also R- L -C -4 -S Mignon Receiving set Brothers Popcorn Co., Ames, Iowa. stamps. Naturopathic Publishing Co., no E. designed for one -step amplifier. Best offer takes Wanted -Small Gasoline and Steam Engines, 41st St., New York. it. F. W. Mann, 523 S. Park St., Kalamazoo, Michigan. Small Lathes, Drill Presses and other, light ma- Concordia Magazine contains essays, short chinery. Will pay high cash prices for good stories, travel stories, boy scout news, editorials, For Sale. Bicycle, new, fully equipped. Carl material. Johnston, West End, Pittsburgh, Pa. current events and poetry, formulas and plans. Madden, Clarksville, Ohio. Trine beautiful, evergreen, ornamental firs, any Two years' subscription, soc. Concordia Maga- Must Sell -Complete electrical and chemical address., $t.00. Order 'now. B. B. Lee, Sta. A, zine, 9 Water, York, Pa. laboratory. Send stamp for particulars. Karl Vancouver, Wash. Peterson, Lane, Ill. Perpetual Motion, by Percy Verance. A his- Pershing's famous letter to Foch photograph tory of the efforts to discover same from earliest Exchange -Bausch & Lomb Microscope, fine mailed quarter. Nelson, 1210 South Broad, Phila- days to the present, togethbr with a scientific condition, complete with case, for Audion panel del his, Pa. the of ulti- Receiving set or Audion control panel, complete. discussion regarding possibility its McGill, mate achievement. Profusely illustrated, 357 Lloyd Smith, Nev. Motor Engines and Dynamos. pages. Price postpaid, $2.00. The Enlighten- Two Step Multi- Audi -Fone. Will sell dirt ment Specialty Co., 3o5 Fourth St., Edwards- cheap. Write. Sherman Whiting, 2010 Park Small Motors and Generators. Cancelled Gov- ville, Hl. Ave., Bridgeport, Conn. ernment Contracts. A. C. Motors, $9.50 each and up. 52 Light no-volt generators, 426.50 each; Experimental Electricity Course in 20 Lessons. Bargain. Complete wireless outfit $15. Power- battery-charging outfits, $3o each and up. New By S. Gernsback and H. W. Secor, E.E. A Course ful water motor $5. Clifford Anderson, 2ío5 15th motors % -i2 up to 5 H. P. for all phases and of the theory and practice of Electricity for the St., Moline, Ill. frequencies of current. Write for late bulletin. Experimenter. Ever phase of experimental For Sale. Good printing press, and supplies, Bargains in motors and generators. Address electricity is treated comprehensively in plain including $3 worth of type. Express prepaid $8. Motor Sales Dept., No. 12, West End, Pittsburgh,, English. New experiments are described and Eugene Mauer, 1624 Wis. St., Racine, Wis. Penna. explained and nearly every application of Elec- Motors Electric, no delay, % Hp., . rio volt, 6o life is 160 pages -joo tricity in modern given. Song Poems Wanted. cycle, single phase. New, money -back guaran- illustrations. Flexible cloth covers 5c postpaid. tee, $22.50. We buy motors of various sizes, 25% Stiff cloth cover, $1.25 postpaid. Experimenter with order, balance C. O. D. General Distribut- Publishing Co., Book Dept., 233 Fulton St., New Write the Words for a Song. We revise poems, ing Co., 22 West ist St., Duluth, Minn. York City. write music and guarantee to secure publica- Broadway Just Off the Press-Design and Construction of tion. Submit poems on any subject. News Correspondents. Audion Amplifying Transformers, Radio and Au- Studios, 197C Fitzgerald Bldg., New York. dio Frequency Type. This latest and important Write the Words for a Song. We write music Earn $25 Weekly, spare time, writing for news- book by Mr. Edward T. Jones, late Associate Edi- and guarantee publisher's acceptance. Submit papers, magazines. Experience unnecessary; de- tor of "Radio News," will be of great interest to poems on war, love or any subject. Chester tails free. Press Syndicate, 566 St. Louis, Mo. all radio amateurs thruout the land. The trans- Music Co., 92o So. Michigan Ave., Room 265, formers shown in these books have never been Chicago, Ill. Stammering. described in print before, and have usually been Song -writers' Manual and Guide Sent Free! considered a manufacturer's secret. Anyone who St- Stu -t -t -tering and Stammering cured at has several vacuum tubes cannot afford to do Contains valuable instructions and advice. Sub- mit song -poems for examination. We will fur- home. Instructive booklet free. Walter McDon- without this book because it will enable him to n ll, I05 Potomac Bank Bldg., Washington, D. C. build the necessary amplifying transformers very nish music, copyright and facilitate publication readily. The designs are very simple and rugged, or sale. Knickerbocker Studios, 319 Gaiety Bldg., Tricks, Puzzles and Games and anybody can make them without much New York. trouble whatsoever. Mr. Jones, the author, is a "10 Select Card Tricks" and latest catalog of practical man who is an experimenter himself You Write the Words for a Song. We'll com- pocket tricks, jokes and novelties 6c. Lowest and knows whereof he speaks. The book is pose the music free and publish same. Send prices. Send today! Lyle Douglas, Sta. A -r, printed on good paper and has an attractive Song Poem today. S. Lenox Co., sot West and Dallas, Texas. cover in two colors. Paper bound. Size 5 in. x St., New York. Send ten cents for large (beautifully illus- 7 in. Contains many illustrations, diagrams and trated) catalogue which contains all the latest working data necessary to build the transform- Song- writers. Market your compositions. Our tricks, jokes, puzzles and illusions. Oaks Price, 25e. successful plan brings results. Work examined Magical 549, ers. postpaid, The Experimenter free and honest advice given. Morrison Music Co., Dept. Oshkosh, Wis. Publ. Co., Book Dept., 233 Fulton St., New York. Shop, Dept. E, Indianapolis, Indiana. Magic. Entertain at home. Tricks, puzzles, Old E. E. Back Numbers. We have some valu- novelties. Send for free catalog. Martinka & able old E. E. back numbers on hand as follows: You Write Words for a Song-We write the Co., Inc., 493 Sixth Avenue, New York City. 1915 -Jan., March, April, May, June, July. Aug., music, publish and secure a copyright. Submit Tricks, escapes, puzzles, photos, books, cata- 'ept., Oct., Nov. and Dec.; price each, 35c. poems on any subject. The Metropolitan Studios, logues free. Magicraft Co., Dept. G, Box 25r, i6 -Jan., March, May, June, Nov., Dec.; 914 So. Michigan Ave., Room 113, Chicago, Ill. Detroit, Michigan. 'ce each, 35c. 1917-Jan., April, Aug., Magic-Card Tricks. Sensational escapes, jokes, , Dec.; price each, 35c. 1918- March, May, Write a Song -Love, mother, home, childhood Everything the amusement line. July, Aug., Sept., Dec.; price each, 5c. patriotic or any subject. I compose music and novelties. in, guarantee Large illustrated catalogue of a thousand tricks Jan., Feb., March, April, 35c.; May, publication. Send words to -day. free. Write today. Largest amusement goods Aug., Sept., Oct., and Nov., price each, roc. Thomas Merlin, 326 Reaper Block, Chicago. in the world. Heaney Magic Co., in., Feb., April, 2oc. We can fill orders at manufacturers ion receipt of your remittance. If you Instruction. Desk 212, Berlin, Wis. t these numbers already, now is your Marvelous Handcuff Escapes. How accom- get them, as they probably will be Crystal Gazing -The craze. Send self- addressed plished. Professional secret. Send 12 cents to o very quickly. Experimenter Publish - stamped envelope for free instructions. Zancigs cover postage, etc. Money back if not satisfac- 3 Fulton St., New York City. Studio, Asbury Park, N. J. tory. O. Kam, 834 No. 8th St., Manitowoc, Wis. You benefit by mentioning the "Electrical Experimenter" when writing to advertisers. April, 1920 ELECTRICAL EXPERIMENTER 1343

Patent Attorneys. For Inventors. Typewriters. Typewriter Ribbons all typewriters, 5oc. The Expert Personal Service of this "Sell or Finance Inventions." Read Money - Patents. sample copy. Abolt Typewriter Company, 38 East 23rd St., firm is of great importance to you in properly Talks Magazine. Send for tree New York. 1897). 7o -B Park Place, Newark, N. J. protecting your invention by patent. (Est. Typewriters $15 up. Fac- 2. Write to John B. Thomas & Co., 902 F Street, Inventions Wanted -Cash or royalty for ideas. Startling Values in Shipped on trial. ' N. W., Washingon, D. C. Mfg. Co., 205 St. Louis, Mo. tory rebuilt. All makes. Adam Fisher Write today for our Special Offer No. 158 -B. Patents Procured -Trade Marks Registered. A 900 Mechanical Movements, also illustrations Ribnsaver makes pale ribbons like new for one comprehensive, experienced, prompt service for explaining so Perpetual Motions. My book, cent. Order today, 5oe postpaid. Whitehead the protection and development of your ideas. "Inventors Universal Educator," fifth edition, Typewriter Co., 186 N. LaSalle St., Chicagb, Ill. Preliminary advice gladly furnished without tells how to procure and sell patents. Govern- form for from charge. Booklet of information and ment and other costs. Covers the matter W ireless. disclosing idea free on request. Richard B. A to Z. Mo pages elegantly bound. Contains D. or Owen, i o Owen Bldg., Washington, C., noted decisions of U. S. Supreme and State The Audion. Its early history and develop- 2278 T, Woolworth Bldg., New York. Courts on patent cases. Mechanical Movements new ideas that ment, Electron Theory and Trigger Action com- Patents, trade -mark, copyright, inventors, greatly assist inventors, suggest piled by a Chief Electrician Radio who was sta- business men, artists, write. Metzger, Wash- may prove of great aid in perfecting inventions. tioned at the Naval Radio School as Instructor ington. Tells how to select an attorney. Has valuable by an old amateur for information regarding Patent Sharks, Selling for two years, written M. F. Miler, Ouray Bldg., Washington, D. C. the amateurs in words that they can understand. Ex- Agents and Brokers. Price $2. Postage free diagrams for hook ups for re- Patent Attorney, Mechanical and Electrical Fred G. Dieterich, 603 Ouray Bldg Also blue print pert. Best quality of work and results. Moder- everywhere. ceiving damped signals, using both air exhausted ate charges. Advice free. Washington, D. C. and gas bulbs. Receiving undamped signals and Inventors write me about patents. My fees regenerative circuits. Two -step amplifier, using "Inventors' Adviser" sent tree on request. payable monthly. Booklet free. Frank Fuller, for both steps. Wire- Linton, 418 F Street N. W. Wash- same (A) and (B) batteries William C. \ ashington, D. C. with power bulb. Working blue ington, D. C., 363 University Street, Montreal, less telephony idea prints on how to build a "One to One" trans- Canada. Inventors, protect yourselves. Record former for use with Audion Amplifier. All for lose rights to patent protection. before exposing it to anyone even myself or Don't your Eng., Reg. Patent $2.00. Address T. O. McKenzie, 104 Warburton Before disclosing our invention to anyone send other attorneys. Klein Cons. Ave., Yonkers, N. Y. for blank form 'Evidence of Conception" to be Attorney, 25 Park Row, New York. be signed and witnessed. Form and information Switch Points- Approximately 1/a "xl -head "Inventors' Guide" free on request; gives 35c. Sample 5c. Toledo Radio concerning patents free. Lancaster and Allwine, valuable advice and information for all inventors. shank 34" -dozen 242 Ouray Building, Washington, D. C. "Origi- Specialties, Toledo. Registered - Patent At- of Form "Evidence of Conception." Write Frank Ledermann, nators the torney, 17 Park Row, New York. Special! Marconi Vt. two step amplifier $18. Jenner, patent attorney and Harold Jones, Ferndale, Wash. Patents-Herbert model, tool, Complete. mechanical expert, 622 F St., Washington, D. C. Inventors -We do experimental, Complete Receiving Sets, $7.00 and up. With can he had and its exact cost. die and jig work- light manufacturing. Miller I report if patent Minn. Low ohm receiver, tested mineral; guaranteed. Send for circular. & O'Brien Mfg. Co., Saint Paul, Bulletin for stamp. Jenkins, Room 2, 923 Pur- .®mame.o® Mass. E. L. Greenwald, McLachlen Bldg., Washing- Personal. chase St., New Bedford, ton, D. C. Attorney -at -Law and Electrical Attention Amateurs! If you are building your Engineer. Formerly Examiner, U. S. Patent outfits we can supply you with Electrical Patent Matters a Sp -cialty. Write to famous Hawaiian Beauties, Swim- own wireless Office. mers, etc., membership 25c. Hawaiian Corre- hbre, and, Bakelite- Dilecto, in sheet, rod or tube, Patents -Fees in installments. Frank T. Ful- pondence Club c/o L. de Roo, Box 306, Honolulu, cut to size. Also brass, sheet, rod, screws, and ler, Formerly Lieutenant, Engineers, Washing- Hawaii. nuts. Switch points, levers, knobs, and binding ton, D. C. post. Experimental and machine, work, done to Patents -Prompts personal effici_nt service by The Salasman Win$. Thousands of positions your sketches. Send for our new price list at an attorney -at -law, skilled in all branches of open. We teach traveling salesmanship by mail once and save money. O. L. Bortz,t1achine Co., Patent Practice. Over 12 years actual experi- and guarantee offer of position or refund tuition. Greenville, Pa. ence- full information upon request. B. P. For interesting particulars address Kansas Vo- posts, switcn 330 Bldg., Washington, D. C. cational Bureau, Miltonvale, Kansas. Switch Points. Binding levers,' Fishburne, McGill and small parts; send 2C for catalogue aescribing Co., 23 of model of your inven- M.n-Enjoy the pleasures of life; have pep, these and other goods. A. W. Bowman & Inventors, s-nd sketch known Cambridge, Mass. . tion for opinion concerning patentable nature strength, courage. Try NERVO, the best Church St. (Harvard Square), Book, tonic; quickly restores strength to those suffer- with con- and exact cost of applying for patent. weak, run-down Audion Control. Bakelite panelled, "How to Obtain a Patent," sent free. Gives in- ing from despondency, nervous, denser, grid leak, audion- ultraudion switch, on patent procedure and tells what condition. Write for interesting literature. cabinet holding 40 volt "B" bat- formation 1440 Niagara, Denver, Colo. rheostat and every inventor should know. Established twenty - Superior Supply Co., teries. Present batch $io.00 each without bat- 414 Dept. 24. Edmund five years. Chandlee & Chandlee, Seventh commommrinmemin teries postpaid. You will be delighted. St., N. \V., Washington, D. C. umtemotwesn Gunning, 273 West 22nd, New fork. Poultry and Animals For Sale. foot, Get Your Cwn Patenta: Save attorn ^y's fees; Genuine "Jupiter" Aerial Wire i cent per $9,00 per thousand. Seven strands Number 22 information and instruction free. Carl Larsen Raise giant rabbits for me. I furnish breeders Strong. Co., Park Row Building, New York Ci.y. cheap, and buy all you raise at 3o to foc per solid copper. High Conductivity. Hundreds make big money. Send Large surface. Low resistance. No. C. O. D. pound alive. 8 Moen Do you know every move your attorney loc for Breeders Instruction Book, contract, Send posts e. Lee A. Bates, Street, makes. .Inventors, my clients are immediately price list, etc. F. Cross, 64o7 Ridge, St. Louis, Worcester, Mass informed of every step in the prosecution of Mo. "Silverplate" without electricity. Modern, effi- their applications; write now, send sketch. Office cient apparatus all silverplated. Bottle "Silver - of Warner I. Cubberley, Patent Attorney, 22 Roots and Herbs. plate" plates whole set, BSc. Roberts, 11718 De- ytonaUnion Bldg., Wash., D. C. troit Ave., Cleveland, Ohio. l Ginseng. $10,000 from % acre, easily grown Apparatus, too I lions spent annually for Ideas. Hundreds in North America. 200 seeds add planting How to Make Wireless Send.ng ow wanted! Patent yours and profit! Write sructions only foc. Box 3, a in- pages, 88 illustrations. Written and published for the wireless enthusiast who wants day fer free books -tell how to protect your- West Milan, N. H. entirely more 1111111111011111WW.m..®..1..01W1110 ., IRMIZIIME1110 his own radio apparatus. Contains se,If how to invent, ideas wanted, how we help to make other ou sell, etc. 212, Patent Dept. American information on "How to make it" than any Rubber Stamps. book we know of. Paper bound, 25C postpaid. dustries, Inc., Washington, D. C. Book Dept., 233 Rubber Stamps made to order. McCaddon Com- Experimenter Publishing Co., Patents-Trade -marks. Complete explanatory pany, Zanesville, Ohio. Fulton St., New York City. booklet on request. Reasonable terms. Prompt, amonssunimmoommamon Receiving Apparatus. now. Clarence O'Brien, How to Make Wireless personal service. Write Stamping Names. too pages -90 illustrations. Only strictly modern Woodward Building, Washington, D. C. radio apparatus are described in this book and the illustrations and descriptions are so clear Patents. In all matters pertaining to invention Maka 919 a hundred stamping names on key - no trouble will be experienced 118 Ful- 25c. for sample and particulars. and simple that consult National Institute of Inventors, checks. Send in making the instruments. Paper covered. ton, New York City, having three thousand mem- Ex Keytag Co., Cohoes, N. Y. Co., bers. Booklet free. mmommoommunumffonnmematmmummvummmmtennumwommommtwasummumnossmatmut BookpDept., z33_FultoniStntNewPYork City. ammonnoseannnemminvoimmormminmonommanommamnammewmommo Stamps and Coins. Wanted to Buy. Just Off the Press-Design and Construction of Stamps -12 different from warring nations, toc. Audion Amplifying Transformers, Radio and Au- latest and important when you mail us old 10 different foreign coins, 25e; to Uruguay dio Frequency Type. This It is l'ke finding money stamps for Inc. Lists free. Toledo Stamp Com- book by Mr. Edward T. ]ones, late Associate Edi- or broken watches, false teeth, brooches, brace- of interest to old gold, silver, pany, Toledo, Ohio. tor of "Radio News," will be great lets, old or broken jewelry, all radio amateurs thruout the land. The trans- platinum, diamonds, magneto points, platinum California Gold, quarter size, z7c; half -dollar books have never 'Deer, ,. mercury, and formers shown in these _ wire, contact points or crucibles, size, 53c. Columbian nickel and catalogue toe. described in print before, and have usually been anything valuable. We pay the highest prices Norman Shultz, King City, Mo. considered a manufacturer's secret. Anyone who in cash by return mail. Goods returned in ten to do Stamps All Different Free. Postage, 3c. has several vacuum tubes cannot afford days if you're not satisfied. The Ohio Smelting -6r without this book because it will enable him to & Refining Company, 2o6 Lennox Bldg., Cleve- Mention paper. Quaker Stamp Co., Toledo, O. transformers very land, Ohio. build the necessary amplifying 200 All Different Stamps, including Bosnia, readily. The designs are very simple and rugged, Bavaria, China, Guatemala, Bulgaria, Bohemia, and anybody can make them without much For Sale -Good typewriter. Sell cheap or Mr. the author, is a trade. W. P. Smith, Crescent, Iowa, Box 273. Poland, Turkey, etc., and Dime Stamp Album, trouble whatsoever. Jones, only one to customer, all for 25c. Our approval practical man who is an experimenter himself he speaks. The 'book is Cash for Old False T-eth -We pay up to $3 .00 sheets contain bargains priced at rc. to 5c. net. and knows whereof Also discarded iso different U. S. postage and Civil War reve- printed on good paper and has an attractive per set (broken or not). buy Size 5 in. x g erd jewelry, gold crowns, bridges, platinum, nues for only 75c. Indiana Stamp Co., Dept. E, cover in two colors. Paper bound. Indianapolis, Ind. 7 in. Contains many illustrations, diagrams and diamonds, watches and silver. Send now. Cash to build the transform- 1 held 5 to to days for working data necessary by return mail. Package Have you seen The Stamp Herald? Finest ers. Price postpaid, 25c. The Experimenter sender's approval of our offer. U. S. Smelting New York. Works, Dept. 73, Chicago, Ill. monthly stamp paper published. Subscription Publ. Co., Book Dept., 233 Fulton St., SOc. a vear. 3 months' trial for 10e. Stamp Herald Publishing Co., Dept. E, Indianapolis, Ind. Wireless Course in 20 Lessons. By S. Gems- Printing. back, A Lescarboura and .H. W. Secor, E.E. Old Coins Wanted. Tells you everything you want to know about r calling cards. Style sheet sent on re- "Wireless" theory, practice and history. A clear, Classy of subject. quest. Arrow print, 333 Walnut St., Waterbury, We Buy and Sell Old Coins. $2 to $500 each concise course on every phase this Conn. paid. Keep All Old Money; you may have valu- 16o pages -35o illustrations, yt tables. Flexible able coins. Send Inc. for New Illu- rated Coin cloth cover, 75c postpaid. Stiff cloth cover, $1.25 Book 3000 two color labels, $1.25. Irvin J. Wolf, Sta- Value Book, 4 x 6. Guara - ices. Get postpaid. Experimenter Publishing Co., tion E, Philadelphia. posted. Clarke Coin Co ' toy, N. Y. Dept., 233 Fulton St., New York City. You benefit by mentioning the " 94 ,hen writing to advertisers. 1344 ELECTRICAL EXPERIMENTER April, 1920 ffea5ggtA43ean Thru

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