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www.americanradiohistory.com 306 THE ELECTRICAL EXPERIMENTER November, 1915

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Yon benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com The EIlectrncaIl Experimenter Published by Experimenter Publishing Company, Inc. (II. Gernsback, President; S. Gernsback, Treasurer; M. Hymes, Secretary), 238 Fulton St., New York Vol. III Whole No. 31 CONTENTS FOR NOVEMBER, 1915 No. 7

FRONT COVER -"THE RADIUM DESTROYER" ILLUMINATED STEAM CURTAIN GIVES WONDERFUL EF- From a Painting by Thomas II, Wrenn FECT AT NIGHT 332 THE ELECTRO. MAGNETIC GUN ANI) ITS POSSIBILITIES 309 ELECTRICITY AND THE TWENTIETH CENTURY DENTIST 332 BARON MUNCHHAUSEN'S NEW SCIENTIFIC ADVENTURES "TIIE CONSTRUCTOR" DEPARTMENT 333 By Hugo Gernsback 312 HOW TO BUILD A DICTAPIIONE DESK SET 333 WARFARE OF THE FUTURE 315 CONSTRUCTION OF AN INDUCTIVE TUNER WHEN THE LIGHTS WENT OUT ON THE "BELLA" 316 By Milton B. Sleeper (Conclusion) 334 -335 WHAT THE HOUSEWIFE SHOULD KNOW ABOUT ELEC- "RADIO" DEPARTMENT . 337 TRICITY 317 THE AMATEUR RADIO STATION \VI -IICII AIDED UNCLE SOMETHING ABOUT SELENIUM 318 -320 SAM By Charles E. Apgar 337 -338 WIRELESS TELEPHONY NOW FROM WASHINGTON TO A POCKET WIRELESS SET 338 HONOLULU 321 A MACHINE THAT CAPTURES AND HOLDS WIRELESS PHOTOGRAPHING SOUND WAVES ELECTRICALLY...... 322 -323 TALK 339 DANIELS NAMES NAVAL BOARD 323 HOW WIRELESS WAVES TRAVEL AROUND THE EARTH'S SOME NEW X -RAY APPARATUS . 324 CURVATURE 340 READING ELECTRIC METERS WITH A CAMERA 326 HOW TO BUILD A WAVE METER By Samuel Cohen 341 MISHAPS ATTEND USE OF WIRELESS ON AEROPLANES... 326 "HOW-TO-MAKE-IT" DEPARTMENT 344 MASSIVE ELECTRIC GENERATOR HOLDS AUTOMOBILE 327 "WRINKLES, RECIPES AND FORMULAS" MIND -READING DOG IS A PUZZLE TO SCIENTISTS 327 Edited by S. Gernsback 347 HIGH FREQUENCY CURRENTS AND APPARATUS "WITII THE AMATEURS" 348 -349 By H. Winfield Secor 328-329 "LATEST PATENTS" DIGEST 350 STEPPING STONES FOR JUNIOR ENGINEERS 330 "PHONEY PATENTS" 351 AUTOMATICALLY CONTROLLED ELECTRIC OVEN FOR QUESTION BOX" 352 TESTING SHRAPNEL 331 PATENT ADVICE" ;'r .:.fatr . ek 361 hJIJLJh}l III 1J 110I1J I liL1LI1IIJ1LhJII,II1J1ILJIi ogRARY h' eTENT Of New York P 110-2) to nolulu11UL by Radio MAR 1 1J EPTEMBER 29, 1915 marks ot er further 4a this distancé: Indeed, we do not milestone in the history of Wir- PATgtis EFL at if we had only the proper receiving On that date, for the first time, the hu- apparatus, Mr. Vail's voice could have been man voice was projected through free space clearly heard over twice the covered distance. over the immense distance of 4,900 miles. The Indeed we are not at all sure that the waves new wireless telephone here triumphed over the from the smallest amateur station do not travel old wire telephone in an astonishing manner, for all around the world. While this may sound up to this time the greatest distance covered by fanstastic, let us consider that each succeding the wire telephone was but 4,750 miles. Nor is year, as our detectors become more sensitive, the vanquishing of this enormous distance by the less and less power is required for transmit- Radio Phone the greatest accomplishment of the ting. With a modern amplifying set, small sta- feat as a whole. For when Mr. Vail at New tions can now be heard over astonishing dis- York on that memorable date hurled his voice tances, never dreamt of less than a decade ago. through 4,900 miles to Honolulu, where Lloyd In this respect we can compare the detector Espenschied caught it over his aerial, Mr. Vail with a telescope. The more we can magnify, the was not using the Wireless Phone at all. He further we are enabled to see, and there seems spoke into an ordinary desk phone transmitter to be no limit to the distance that can thus be and his voice was thence relayed by the big Ar- covered. It is precisely the same with a Radio lington Wireless station. Here, 'by means of gas detector ; the more sensitive we can make it, valves of the Audion type, the impulses of the the further away will we be able to receive mes- voice were "stepped up" till they were finally sages from a given station. There seems to be strong enough to operate the sending apparatus. no limit to the distance that can be covered in Thus the feeble voice arriving at Arlington ab- this manner. several hundred horsepower solutely controlled Truly, while this recent feat has been a signal kilowatts to be accurate it was this -30o -and achievement, we confidently look forward to that enormous energy that was then radiated out into time -not far off, we think -when it will be pos- space for thousands of miles. While we know sible to talk from New York to Chicago with a definitely that during this test the human voice power derived from six small dry cells. was carried through 4,90o miles of ether, it is quite certain that the impulses were carried much H. GERNSBACK. L11J 111J4 14--,STI

L1JLJLJh1Jh1J11'.JIJl1Jl1JhJl11l1Jl1Jl1J+. 1111 . J 1 11L 1 11L 1J LI, . J L 1J _ L Jl . 11 l 11 1 J_11 IJL! J l! i i www.americanradiohistory.com_107 308 THE ELECTRICAL EXPERIMENTER November, 1915

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www.americanradiohistory.comC1 I THE ELECTRICAL EXPERI M ENTER

H. GERN 5 B ACK EDITOR H. W. 5ECDR 115512CIATE EDITOR Vol. III.Whole No. 31 NOVEMBER, 1915 Number 7 The Electro- Magnetic Gun and Its Possibilities WRILE we have heard of many dif- and the switch is moved so that coil 3 will and not at all compared to the heat pro- ferent kinds of life destroying be put into the circuit and coils 1 and 2 duced in the modern high powered guns guns and other weapons during opened. Thus the projectile will again be using explosive charges of powder. Due the present European conflict in all its pulled forward to section 3, and at the in- to this and other obvious reasons such a magnitude, there are probably not many of stant it reaches the center of the final coil gun as this can fire a great number of us who have stopped to think of the pos- the current is cut off and the momentum larger caliber shells per minute, possibly sibilities of a somewhat unknown inven- acquired by the projectile is relied upon to fifty to seventy-five shells in one minute. tion which relates to nothing less than the carry it on and out of the muzzle of the It will be seen from the foregoing that hurtling of large projectiles through space gun at B. This design is the basis of such a discharge of 19 -inch shells, each of by means of electro- magnetism properly most of the patents on this unique device, which contains a very high explosive applied to a gun or cannon barrel. which has yet, we may say, to be proven in powder charge, would serve to quickly rout There have been several patents issued a practical sense for modern warfare re- the enemy, no matter how well he might on such devices, but to our knowledge quirements, although it seems indeed to be entrenched or ensconced behind forti- none of these have been adopted by any possess possibilities if the details are prop- fied embankments. A rain of such monster of the world powers. As an introductory erly worked out. shells would batter down almost any forti- explanation reference may be made in this The wash drawing illustration here pre- fication whether natural or built by man. connection to Fig. 1, and undoubtedly the sented at Fig. 2 shows how we may con- A method is suggested in the illustration reader will then be able to grasp, with the- duct warfare in the future if the powers of this electromagnetic gun of the future aid of the following explanatory remarks, that be still think that the only way to whereby a constant supply of shells for about how the various inventors of the settle an argument is by main strength and rapid firing can be always maintained be- electro- magnetic guns intend hurling their ignorance. In our illustration is shown a fore the open breach of the gun. The projectiles at the enemy with hair -raising probable development of a large electro- shells might be hoisted by means of a rapidity and accuracy. magnetic field gun mounted on a massive gasoline engine and run on the platform Referring to Fig. 1, and for the sake of iron frame -work fitted with large cater- at the left and then allowed to slide by simplicity, we may consider that but three pillar wheels, as observed, so that it is gravity down the inclined chute. As fast electromagnetic coils are in use as at 1, mobile enough to be quickly hauled from as one of the shells is sucked into the 2 and 3 along the gun barrel. It may be one place to another on the battlefield or breach of the gun barrel it is followed by said that invariably such a gun barrel for siege purposes. When used for port- another one right after it successively. It should haye an inner lining of brass or able requirements it will invariably be ne- is easily possible to have means of firing bronze, so that the projectile which is cessary, if such guns are ever adopted, to the shells as far apart, in respect to time, usually made of a magnetic material (such provide a complete portable electric gen- as is deemed advisable, of course. The as iron or steel), will not bind within the erating plant as is shown in the picture. electric current supplied through the coils barrel. The barrel proper can be made of This would comprise a powerful gasoline along the gun barrel can be controlled iron properly divided, but an all -brass bar- engine direct connected to a suitable elec- through a suitable switch by the man aim- rel is common. Now consider that the tric dynamo. ing the gun and who may be located along- three magnet coils, 1, 2 and 3, are con- Some idea of the probable size of such side of the breach of same as perceived in nected up to a switch as shown. If, then, guns may he obtained when it is stated that our illustration. an iron projectile is placed in the position one of the best designs ever worked out Such guns as these firing 19 -inch ex- A, and the current caused to flow through on this principle, and due to Prof. Birke- plosive shells may have a range of twenty - the coil 1, the electromagnetic field of land, has a barrel 90 feet in length. The five miles or more. The shells may carry force set up within the gun barrel will projectiles used in this gun would be about time fuses, or they may be of the contend to pull the projectile forward in the 9 feet long and have a diameter of 19 cussive explosion type, whereby they do direction of the arrow. It should be men- inches. Also to gain the maximum mag- not explode or burst until they hit the tioned before going further that the iron netic pull by this arrangement it is recom- ground or the wall of a fort, etc. barrel (if used) of the cannon or gun is mended that the projectile be wound witrt Of course, these magnetic guns are prac- divided up into several distinct sections coils of wire so as to be electromagnet- tically noiseless and naturally also abso- so as to localize and intensify the magnetic ically reactive in conjunction with the lutely smokeless. Furthermore the wear pull on the projectile at each new impulse. regular magnetic disc coils placed along the and tear or depreciation, in so far as the Of course, this scheme outlined at Fig. barrel of the gun as perceived. In order gun barrel lining is concerned, is very 1 is only mentioned to bring out the gen- to facilitate the passage of the projectile low compared with modern cannon and eral theory of how these guns are sup- through the barrel of the gun with the other arms using explosive charges to exposed to operate. To continue: when the least friction we strongly suggest that suit- pel the bullet or shell from the barrel of projectile has reached the position of coil 1 able lubrication be provided by means of same. The shells or bullets in such cases the control switch is moved so as to cut grease or oil cups placed along the barrel must fit very tightly so as to prevent the out coil 1 and to connect coil 2 into circuit. at intervals; these may be observed in our exploding charge in the gun barrel from If this is done quickly the projectile will illustration Fig. 2. leaking out and at the same time to force have been sucked forward on a line with It must be remembered that these guns the shell outward with all available power. coil 2. The operation is again repeated would not heat to any appreciable extent in magnetic cannon the shell does not THE ELECTRICAL EXPERIMENTER is published on the 15th addressed to: Editor. THE ELECTRICAL EXPERIMENTER. 233 of each month at 233 Fulton Street. New York. There are 12 num- Fulton Street, New York. Unaccepted contributions cannot be re- bers per year. The subscription price is $1.00 a year in U. S. turned unless full return postage has been included. ALL accepted and possessions. Canada and foreign countries. $1.60 a year. contributions are paid for on publication. A special rate is paid U. S. coin as well as U. S. stamps accepted (no foreign coins or for novel experiments; good photographs accompanying them are stamps). Single copies, 10 cents each. A sample copy will be sent highly desirable. gratis on request. Checks and money orders should be drawn to THE ELECTRICAL EXPERIMENTER. Monthly. Entered as order of THE EXPERIMENTER PUBLISHING second -class matter at the New York Post Office, March 1, 1915, CO. INC. If you under Act of Congress of March 3. 1579. Title registered U. S. change your address notify us promptly, in order that copies are Patent Office. Copyright, 1915. by E. P. Co.. Inc., New York. The not miscarried or lost. A green wrapper indicates expiration. contents of this magazine are copyrighted and must not be repro- All communications and contributions to this journal should be duced without giving full credit to the publication.

www.americanradiohistory.com 310 THE ELECTRICAL EXPERIMENTER November, 1915

necessarily have to fit the barrel tightly now produced by the modern explosive tion acting on the projectile will be about and thus friction can be vastly reduced. charge type of cannon. Therefore this in- two thousand five hundred pounds per Moreover, there is no pitting or other ventor proposes to arrange the switches, square inch of the cross -sectional area of wear on the inside of the barrel, due to etc., on his gun so that the current through the projectile. A calculation shows that powder explosions as just mentioned. the coils will only be left on for a very when a firing is to take place the current At Fig. 3 is shown a patent issued to S. small fraction of a second in any case. should be set up one -seventh of a second T. Foster, Jr., (No. 811,913) on an electro- Also in considering the regular approved before the firing. The projectile is then magnetic gun. This patent will serve to engineering design of such magnetic coils set free, and will pass the barrel in the give a fair idea as to the generarmake -up course of one -fifth of a second. The cur- of these devices intended to supplant the rent has then been on the outermost modern artillery now in use by world solenoid about one -third of a second. It, powers. Mr. Foster arranges a series of however, a construction is used in which powerful electromagnetic coil windings . ..,-z.. 73çEM28 all the groups of solenoids are not at once along the non -magnetic gun barrel 11 -12. excited less than half the current will be The magnetic projectile made of iron or used for the same effect, and the genera- steel is placed in the breach at 11, just tion of heat in the outermost solenoids will far enough to reach the electric contact 1. be reduced." When this contact is depressed by the shell it closes the electric circuit through the magnetic coil 15. This causes the shell to ENGINEERS FORMING RESERVE be pulled forward, and as the forward CORPS. section of the projectile then engages the The movement begun in a tentative way cut -out switch 2, it depresses same and ex- last spring to form a reserve corps of en- cites the magnet coil 16. The projectile is gineers to be available in case of war has then pulled forward electro-magnetically assumed definite form, according to an- until it is in line with coil 16, and simul- nouncements made by Bion J. Arnold, of taneously actuates the cut -out switch 1, Chicago, chairman of the A. I. E. E. corn- which opens the circuit to coil 15. At this mittee of the proposed reserve corps of instant, generally speaking, the shell in engineers. 16 ago was taken sliding forward into line with coil has 01111111111111111111111111111111111111111110 Some time the suggestion engaged the cut -out switch No. 3 and this up by the American Society of Civil Engi- closes the coil circuit 17, thus the shell is neers, the American Institute of Mining pulled forward into line with that coil and Engineers, the American Society of Me- coil 16 is cut out of circuit, owing to the chanical Engineers, the American Institute contact 2 having reset itself automatically. of Electrical Engineers and the American Thus it will be seen how the iron pro- Fig. J. Electro -magnetic Gun Patent Issued Institute of Consulting Engineers. Each of jectile is propagated through the barrel to S. T. Foster, Jr. these organizations appointed committees to toward the muzzle 12. The operation pre- further the movement, which has now be- viously described repeats itself until the he proposes not only to pass a normal cur- come more closely consolidated by the ap- shell reaches the position of coil 23, and rent through the coil, but a current even pointment, just announced, of 'the chairman here it strikes a cut -out switch 10, which ten times as heavy, or more, and thereby of various committees as members of a joint opens the current circuit. No magnetic momentarily (for the fraction of a sec- committee to take charge of the work in pull is further exerted on the projectile and ond), a terrific magnetic pull can be ex- co- operation with the War Department. it leaves the muzzle of the gun under its erted on the iron shell within the barrel. The members of the committee are as fol- own momentum. The inventor in this case He mentions further (and this is a capital lows: William Barclay Parsons, New claims that the shell is supposed to gain idea) in order to increase the magnetic York, chairman, and Henry S. Drinker, velocity repeatedly and successively as it action in such a gun it is preferable to Pennsylvania; William H. Wiley, New moves from each coil to the succeeding make the projectile of iron surrounded by York; B. J. Arnold, Illinois, and 'Ralph D. coil. This arrangement for cutting out magnetic coils instead of iron alone. Mershon, New York. the coils as the shell moves through the Further schemes outlined in Prof. barrel is followed out in several other Birkeland's patent cover the arrangement patents and seems to be a general idea whereby it is possible to open the magnetic INCREASING WIRELESS RANGE with most of the inventions in this direc- coil circuit without any spark occurring at BY KITES. tion. the break of the contacts. This is accom- The recent manoeuvres in northeastern It would take up too much space here to plished by taking advantage of the fact Massachusetts were of particular interest describe in detail the very ingenious mathe- that the projectile moving through the because of successful experiments by the matical and engineering deductions cited in barrel will induce electric currents in the Signal Corps in maintaining a wireless the wonderful patent of Prof. Kristian magnet coils and at the instant when this aerial at a great altitude by means of kites, Birkeland of Sweden. In his patent (U. induced current is approximately equal to and thereby increasing the efficiency of an S. Patent No. 754,637) he brings out some the current flowing through the coil and ordinary field radio set from six to sixteen very fine points with regard to the develop- which, of course, passes through the coil in times. At the invitation of Adjutant -Gen- ment of the electromagnetic gun. A few the opposite direction to the normal cur- eral Cole of the Massachusetts Volunteer of the considerations there advocated, rent, then the cut -out switch is operated Militia, Samuel F. Perkins, a maker and with no sparking at same. flyer of man -lifting kites, went to Newbury He goes on to say: "As to the dimen- and experimented with the Signal Corps. sions which may be given to guns con- As there happened to be fairly strong winds structed according to my invention, the at the time, Mr. Perkins was able to send following example may be mentioned: For up a string of kites to a height of 1,600 throwing an iron projectile weighing two feet. The messages transmitted from the tons and containing one thousand pounds kite- supported aerial are said to have been of nitro -gelatin at an initial speed of one received 150 miles away with distinctness, thousand feet per second I propose the use although the field wireless set used would of a gun with a length of about ninety only transmit messages 25 miles ordinarily. feet, the projectile being about nine feet The results were obtained because the kites long and having a diameter of about nine- flew so steadily that the aerial was always teen inches. The gun solenoids may be maintained at a constant altitude. The re- made up of square wire, each solenoid con- ceiving qualities of the kite- supported aerial taining seven hundred and twenty windings were remarkable. Messages were received of a total resistance of fifteen ohms. The from the battleship Georgia, off Newport, length of each solenoid is made about and from the Government stations at Ar- three -eighths of an inch and the height lington, Va., and Bermuda. Code messages Fig. i. Elementary Diagram Showing Action being exchanged between two British war- of an Electro- magnetic Gun. (radial dimension) about eight inches. With an electromotive force of three thou- ships out in the Atlantic Ocean were re- hypothetically and otherwise, are outlined sand volts this will give a current of two ceived with accuracy. Further experiments below. hundred amperes. If the current is set up by the United States Government and Mar- In the first place, it has been found dif- simultaneously in all the solenoids (there coni officials are now being conducted, and ficult to make an electromagnetic gun of will be about three thousand elementary it is expected that in a short time the range ordinary size which will exert a sufficient solenoids), this will require altogether six of sending from an ordinary field wireless pull on the projectile to gain the effects hundred thousand amperes, and the suc- set will be increased.

www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 31I

www.americanradiohistory.com 312 THE ELECTRICAL EXPERIMENTER November, 1915 Baron Münchhausen's New Scientific Adventures By Hugo Gernsback

FOR forty -one days I had been terstellar' was entirely gravity -in- "listening in" nightly at my Münchhawen Lands On Mars sulated from the Moon, Earth and wireless set, since that event- Sun. We were then 'falling' towards ful evening when Baron Münchhausen had self? Too bad there is no return 'cir Mars at the rate of 20,000 miles an hour. left the Moon for the Planet Mars. He cuit,' for I would love to hear your dear Within 10 days our speed had increased had said, of course, that it would take from voice. It's over 44 days since I have last to over 50,000 miles an hour, and the Earth 35 to 411 days before the "Interstellar" could heard it. Yet it can't be helped. Well, which from the Moon appeared 14 times negotiate the trip from the Moon to Mars, you must be satisfied to listen to me, with- as large, as the Moon appears to you, had but nevertheless I became more and more out being able to talk back; but I'll try to shrunk and shrunk till it looked like a impatient as the days wore on. be as explicit as possible, so that you will small bright red disc. Mars in the mean- At last on the evening of the 42d day, not be in a position to ask questions. while became rapidly larger and redder at 11 o'clock on the second, the peculiar, "Well, my boy, the trip from the Moon and soon it appeared like an ochre disc. unmistakable high whining spark suddenly to Mars was entirely uneventful. As soon At the end of the 35th day, when our speed broke in my ears. After the long nervous as we had our bearings we made straight had increased to 78,000 miles an hour, due strain, the loud whistling spark, almost for the Red Planet, the Mysterious. Flit - to the proximity of the planet, the Earth took me off my feet and I could hardly ternix and I took watches alternately and had become á bright star in the firmament, hear the first words, I was so excited. In as we had learned from our former ex- somewhat brighter than the other stars, a few seconds the whistling spark died perience how to handle the 'Interstellar, but a pitiful sight compared to what it down, and Münchhauseñ s dcar, sepulchral the trip became more or less monotonous. had looked when seen from the Moon. voice sounded once more in my faithful We liad a little trouble at the start with But remember that the Moon is but 238,- receivers. And how loud it was! It was the switching of the Marconium netting, 000 miles distant from the Earth, while we positively uncanny to think that I was for it proved rather a puzzle to gravity - were now over 50 million miles away from listening to his "canned" voice, which per- insulate the 'Interstellar' from the com- it. Quite a little difference! haps 10 or 12 hours before had been hurled bined attractions of the Sun, the Earth "The next day, the 36th since our start. through the ether some 55 million miles and the Moon, and at the same time hav- we were but 200,000 miles distant from away from the Moon, there to be regis- ing the Planet Mars alone 'pull' us. This Mars, and the planet at this distance was tered phonographically on a telegraphone. bothered us considerably for several days indeed the most gorgeous sight either Flit-

"Three Shafts of an intense Yellow Ray Were Turned on us, and It Was the Peculiar Properties of This Ray Which Nad Made us Captives to the Martians' Superior Intelligence And now the Baron's voice through the and we made but little headway during ternix or myself had ever witnessed. Mars wireless telephone sending plant on the that period. Finally when the Moon, looked now almost as big to us as the Moon, 238.000 miles away from me, was Earth and Sun, in the order named, were Earth does when viewed from the Moon. talking! The thought made me shiver. in a straight line, with Mars almost over- If the Earth when so viewed is a wonder- "Hallo, Alier," it came in a sympathetic head, our speed rapidly increased and on ful spectacle, the planet Mars when seen voice, "how is old mother Earth and your- the evening of the fourth day the 'In- at such a small distance is simply over- Copyright 1915 by H. Gernsback. All rights reserved. www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 313 whelming in its splendor. We saw a full considerably thinner than the terrestrial best thing we could possibly do was to red disc, dazzlingly illuminated by the dis- one, and for that reason it does not ab- submit ourselves entirely to the Martians' tant Sun's rays. Like the Earth, Mars sorb so much light.t will. Indeed, we were so helpless that we has a pink fringe running around the edge "After circling around Mars at a height could not have offered any resistance, even -its atmosphere. The continents stand of 10,000 miles for some time, we finally had we wanted to do so. We, therefore, forth in an ochre red, intermingled with decided to make a landing. By careful calmly awaited developments, for we rea- dark green patches. Faint lines run over maneuvering and switching of our anti - soned instinctively that we would not be the entire face of the planet, like cobwebs gravitational Marconium netting, we finally harmed. Nor were we mistakcn in this -the famous Martian canals. At the top descended to a height of but five miles view. a brilliant white cap is observed -the north from the surface of Mars. On account "The yellow rays guided the 'Interstel- polar ice fields. of the etherless zone of the Marconium lar' over a vast distance and at the end "But the most wonderful sight to us was netting when switched on, we could, of of an hour we were gently deposited on a Mars' two little moons. Flitternix calls course, not see what was beneath us at huge grassplot in a fairyland 'City.' The them toy moons! Of instant that our flyer's these we had the best broad landing belt view the next day when touched the ground the we were but some 10,000 IS Mars really inhabited by intelligent beings? Are conditions on this yellow rays disappeared miles distant from Mars. Planet such life can be sustained on it? Some of the foremost a n d immediately o u r *t "The Planet Mars that normal facilities were has two tiny moons, thinkers in astronomical matters answer these questions in the restored once more. We christened Phobos a n d affirmative. were frce to move and Deimos by terrestrial to act. astronomers. They were The Spectral Analysis has revealed to us of what gases and matter "We lost no time in discovered in 1877 by is By means of unbolting our steel door, Professor Asaph Hall, the Sun composed. those piercing instruments Logic and and in our anxiety to- of the Washington Ob- Deduction, we are enabled to tell what is going on on Mars. This get out in the open, all and they are three of us. Flitternix, servatory, advances some new ideas on and we so minute in size that story the subject have a hunch that myself and Buster, our only the most powerful you will enjoy this installment. fox terrier, almost tum- telescopes on Earth re- bled over each other. I veal them. The largest, admit that on a histori- Phobos, is some 36 miles cal occasion like this the in diameter, while the smaller, Deimos, is all times, for light does not pass through first time a human being sat foot on an- but 10 miles in diametr. The latter is such an etherless zone. We therefore had only other planet, the should have appeared a ridiculously small world that a pedestrian momentary glimpses of the planet during more dignified as, for instance, Christopher would walk around its equator in a single the short seconds when the current in the Columbus did when he first landed on San day ! An automobile, given a fair road, netting was switched off. This constant Salvador. Sad to relate, however, there could circle this entire world in one hour, switching on and off of the current re- was nothing dignified nor solemn to the without exceeding its speed limit! duced our speed to almost nothing, and occasion of our landing, and this was partly "Phobos, the largest moon, is less than we were thus slowly approaching an open due to Buster. That infernal dog insisted 4,000 miles from the surface of Mars and plain which we had picked out and which on running between our feet and succeeded revolves around the latter in the remark- appeared like part of a desert, and prob- in tripping Flitternix just as he placed his ably short time of 7 hours and 39 minutes. ably sandy enough to effect a soft landing foot on the ground; if it had not been for Consequently the Martians witness the of the 'Interstellar.' From our moment- me he would have sprawled all over the spectacle of their largest moon going ary glimpses we had become more than grass. through all its phases in 7W hours I In a convinced that the planet must indeed be "It is a good thing that the Martians have single Martian morning, therefore, Phobos inhabitated by intelligent creatures. We a keen sense of humor, for the crowd that can be seen to rapidly change from new had snatched a good view of a wonder- had collected around our flyer began to moon to first quarter, then full moon, then fully built city; had seen sections of the laugh uproariously in a queer, characteris- last quarter and finally again new moon; mysterious long waterways and their at- tic Martian falsetto voice. I admit that and all this in 73h' hours! A unique fea- tending strips of vegetation, otherwise we offered a sufficient cause for amuse- ture about Phobos, too, is that it revolves known as the Martian canals, and had also ment, the professor in his old Prince Al- quicker around Mars than the latter re- observed ponderous air craft by the thou- bert and myself attired in my costume of volves upon its own axis. Mars turns sand and curious structures near the 1797. However, we quickly managed to around its axis in 24 hours, 37 minutes canals that looked like gigantic pyramids. pull ourselves together and we blinked and 22' seconds. Thus the Martian 'day' "Had we still doubted that Mars was in- around us in unconcealed amazement. is almost 38 minutes longer than the ter- habitated we were taught differently in a "Although the Martian air is very much restrial day. During one Martian day, few minutes, for things began to happen thinner than the Earth's atmosphere, w: Phobos therefore has spun more than three rapidly. experienced but little trouble in breathing times around Mars I As seen from Mars, "When we were still about two miles from for our stay in the rarified air of the Moon Phobos appears about as large as the Moon the Planet's surface, suddenly as if by had taught us how to breathe in thin air. appears to inhabitants of the Earth. magic, everything before our eyes became We noticed immediately that the air was Deimos, the smaller moon, is 12,300 miles yellow. At the same time a peculiar numb very pure and we did not cough once, as distant from Mars. Whereas its larger sensation came over our bodies and we was the case of our landing on the Moon. brother takes but 751. hours to revolve were hardly able to move hand or foot. The Martian air seemed rich with ozone, around Mars, Deimos requires 132 hours Simultaneously the machinery of the 'In- and we could not rid ourselves of the idea to complete its circuit, or almost six days. terstellar' became unmanageable, and look- at first that we were breathing the strong Deimos, however, is so far removed from ing through the lower portholes we could air of a pine forest. Mars and it is such a tiny object that to see that we were rapidly coming closer to the Martians it really does not appear as "But what held us spellbound for some the planet's surface, at the same time mov- minutes was the Martians themselves. 1 a moon at all, as we understand that term. ing in a totally different direction from the view am not sure whether they were not as For it must be apparent that if we one we originally were heading to. as we were; for as we an object measuring 10 miles across from much astonished "With some difficulty we managed to look found out later, the Martian can conceal a distance of 12,300 miles, we can hardly up towards the top port windows and we expect to see much. For that reason his emotions far better than the proverbial Deimos, 'full,' only about saw a marvelous sight. Three circular Indian. While I was still staring at the when appears massive, what looked to us like metal air- nearest Martian with my mouth wide open, slightly larger than the planet Venus ap- were pears to you as seen from the Earth. craft, spaced equal distances apart, Flitternix, who had recovered first from floating in space. The three flyers formed his surprise, nudged me and said: 'Didn't Therefore the Martian nights are not bril- an triangle while in the exact liantly illuminated by two large moons, equilateral I tell you ?' center, but about one mile lower down "Only then did I remember our discourse as some writers would have you believe. than the flyers, our 'Interstellar' was float- we To the contrary, the Martian night is very of the previous day, when were specu- ing. Three shafts of an intense yellow ray lating together as to the probable appear- much like the terrestrial night, except that us it was this light, Phobos when full appears to shed more were turned on and ance of the inhabitants of Mars. I re- or rather the peculiar properties of the member now that Flitternix had said some - light on Mars than the Moon sheds on which had made us captives to the Earth. For the Martian atmosphere is rays thing like this: Martians' superior intelligence. "We have seen on Earth that animal life In order to disinguish facts from fiction in this "We reasoned that these floating forts is possible under the most adverse condi- instalment, all statements containing actual scien- must be used for defensive purposes on tions. We find life at the North Pole in tific facts will be enclosed between two t marks. - AUTHOR. Mars, and we agreed among us that the the most awful cold, and we find life at

www.americanradiohistory.com 314 THE ELECTRICAL EXPERIMENTER November, 1915 the equator in the most intense heat. We tTo begin, it has been proved beyond dis- world than the Earth. Civilization on find life in the thinnest mountain air, and pute that Mars has an atmosphere, which Mars must date back several hundred thou- we find life at the bottom of the ocean. although thinner than that of the Earth, sand years. The law of evolution teaches Particularly the latter is interesting for is probably thick enough to sustain human us that we must therefore expect a very even up to a few years ago scientists of life even as we know it. Professor Lowell cultured as well as accomplished race. note denied that a fairly large creature has proved that the mean temperature on "'As our terrestrial evolution shows, the such as a fish could withstand the enor- Mars is about 47 degs. Fahrenheit. In human head is growing larger and larger mous pressure of water at the bottom of some sections as, for instance, near the all the time. It must have been the same an ocean. For the scientists argued that equator, the temperature can surely not on Mars, for conditions here are almost the fish would be crushed to death by the be less than 65 degs. F. It was argued the same as those on Earth. We must, thousands of tons of water above it. Not in former years that, on account of the therefore, expect to find a race with enor- only that, but it was furthermore argued far greater distance Mars is removed from mous heads. As the air is thinner on Mars that as it gets colder as one descends into the Sun than the Earth, the temperature sound will not carry as well as in a thicker the depths of the ocean the temperature must be far below zero. Recent astronom- atmosphere. We, therefore, will expect finally drops below the freezing point of ical researches, however, completely dis- big funnel -like ears on the Martians to fresh water. How then could a fish live proved this. As a matter of fact, Mars enable them to hear well. But a big head in such an abode? It was simply impos- proper receives really more heat than does almost invariably has big eyes; from this sible. The fish might just as well live in we may safely deduct that the Martians a frying pan. The arguments were strong 1 have large eyes. But there is one impor- indeed against the possibility of life at the tant difference of physicial conditions on bottom of the sea. SYNOPSIS Mars, as compared with those on Earth, 'But a man by name is what weighs t" then of Challenger I. M. Alier, an eccentric young scientist and that gravitation. For came along and invented a deep sea dredge. of Yankton, Mass., who claims as his own one pound on Earth weighs but 0.38 pound, No sooner had his expedition begun to many new as well as startling inventions, or a little over one -third pound, on Mars. dredge fished far ahead of anything as yet discovered, Less bodily makes than they from the bottom owns the largest radio -telephone plant in the weight for excessive of the ocean the most astounding specimen country. One evening he hears strange growth for the reason that gravity pulls of deep sea fish built on a plan to with- noises over his phones and immediately a less on the body frame. A little calcu- stand enormous pressures. True, they sepulchral voice is heard. It is Münchhau. lation based upon the above gravitational sen, one of the greatest yarn and story were dead when they arrived at the surface tellers of all times. Münchhausen explains figures leads us to suspect that the aver- of the ocean, but this was expected, for how it came about that he did not die in age Martian should be about eight feet as soon as the enormous pressure to which 1797, as popularly thought, and he further. tall. An the sunlight is very much stronger more gives unrefi'.table proof that his home the fish was accustomed was taken away, is on the moon at present. on account of the thin air on Mars, the he naturally burst inside. So our "wise" Alter wants to know why Münchhausen Martian unless he is in the shade most of scientists with their beautiful logic were went to the Moon aiid how. The latter then the time has probably a dark skin, which explains how Prussia persecuted him and wrong once more and the impossible, as how he went over to the Allies and suc- may be as red as that of a North Amer- always, was very much possible.t ceeded in capturing Berlin in a wonderful ican Indian or as dark as that of a West "'I mention this only in passing, to show manner. However it was not a complete Indian, success, so the fiaron left Europe for you that life can accustom itself to almost America. He immediately constructs a "'As the air is so thin on Mars and as any condition. There are indeed but few machine which is to take him into space to oxygen is needed in large quantities for exceptions to this rule to my mind. Now, the moon. Münchhausen has discovered such big bodies as the Martians', we will how to neutralize Gravity by means of then, we have absolutely no right to be- Electricity, and he applies this invention to not be surprised to find that the Martian lieve that the little planet Earth, among his space flyer, the "Interstellar." The has an immense torso, to accommodate his the billions of worlds, should be the only machine proves a success; it responds and ponderous lungs. The latter must be is lifted with tremendous speed towards the fortunate one on which life thrives. moon. doubly large in order to sustain such a tArrhennius has demonstrated already Queer things are discovered on the way large body and also to work over quickly how life is propagated from one planet to to the Moon, among others that bodies lose the small percentage of oxygen in the thin all their weight inside of the "Interstellar." air. But large lungs also invariably re- another. This famous philosopher has Finally a landing is effected on the Moon shown, that minute life carrying spores so in a desert, but great hardship is encoun- quire a large nose, as we know from ex- small that they cannot be seen by the tered on account of the Moon's rarified perience, on earth. Consequently, if the atmosphere. The party then leaves for the a naked eye are carried through space, pro- nearest mountain range, where they dis- Martians have ponderous nose, don't be pelled by the pressure of the sun light till cover a huge subterranean cave and a lake surprised, for evolution shows us that they strike another heavenly body. If the filled with luminous fish. Bread trees are animals breathe through their noses as a also discovered. Münchhausen next gives conditions are suitable the spore will germi- a vivid description of the Earth, Sun and rule. nate in time and life will spring up-if it the firmament as viewed from the Moon; he As to the Martian's hands, it is prob- is not there already -on that world. It also explains how the continents and oceans able we will find them rather small in proof the Earth appear from the Moon. He has been proved that these spores can exist then tells of the ponderous meteors which portion to the rest of the body. The in an absolute zero and in a perfect vacuum continually crash down on Moon. Martians have probably advanced so far Finally the for years, without losing their germina- one falls down near him and the =_ that manual labor has been abolished for resulting concussion hurls Münchhausen in tion power-another proof how nature pro- a bottomless crater, which goes straight hundreds of generations. It is almost cer- tects life under almost unbelievable con - through the Moon. He falls clear through tain that as everything must be done with ditions.t Therefore to say that there is to the other side, but his momentum brings machinery, manual labor is absolutely un- him back to the starting point, where he life only on the Earth is not only idiotic is saved by his companion. They then de- known to -day on Mars. This naturally, in the extreme, but it also reveals a total cide to depart for the Planet Mars, but in the course of several thousand years, lack of appreciation of the wisdom of they leave behind them an automatic Wire- begins to tell and the hands must shrink. less Plant, the "Radiotomatic," which will Almighty Nature. relay the messages from Mars to the Moon We will therefore expect that the eight - "'Now, then, it is an undisputable fact and thence to Aller. A popular lecture foot Martian has a hand rather smaller that plants, animals as well as humans, on Mars is also given by Münchhausen. than ours. Again, as no physical labor are entirely dependent upon their sur- THIS STORY STARTED IN THE MAY ISSUE. of any sort is performed by the Martian, roundings. If, for instance, you take an BACK NUMBERS WILL BE SUPPLIED AT 10e. his arms are probably thin and muscleless. Eskimo and transplant him and his family EACH POSTPAID " 'Ais to his feet, we shall find them to be very large in all probability. They must on an island under the equator, his white 111111111111111iII11111111111111111111111111Ìllllll isIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIfIIIIIIIIIIIIIiIQIIIIIIIIIIIIIIIIIIIII color will change into black in a few gen- support a tall and rather heavy body, and erations. Likewise evolution shows that the Earth for the following reasons: The they, therefore, must provide sufficient lev- the human body very quickly adapts itself Martian atmosphere is much thinner than erage to enable the Martian to walk prop- to the tasks imposed upon it. Thus a man the terrestrial, consequently the Sun's rays erly. Not alone for the latter reason must whose grandfather and father were hard- pierce it with far less loss than is the case the feet be large, but also on account of working laborers, will nine times out of on Earth. Then, too, there are no clouds Mars' small gravitational attraction; for ten inherit a bony as well as robust body on Mars to cut off almost 50 per cent. of if the Martian's feet were small, he could and a relatively small brain. Whereas a the received Sun's rays, as is the actual not secure the proper foothold to propel man whose grandfather and father were case on Earth. his body, he would be hopping instead of mathematicians nine times out of ten will "'Then again the Martian day is almost walking. have a comparatively small boned body, exactly as long as the terrestrial. Also Therefore when we behold the first which is far from robust, but his brain due to the inclination of the Martian axis, Martian we will probably find him to look will be large. which is almost exactly the same as the totally different from a human being,'and "'Surroundings are everything and given one of the Earth, the seasons are exactly while my reasoning as to his probable ap- time they will transform man or animal like the terrestrial ones except that they pearance may be inaccurate in spots, I am into different beings than they were orig- are twice as long, because the Martian year sure that on the whole I will be correct' inally. is just twice as long as the terrestrial one.t "So spoke Flitternix. "'Now let us apply this reasoning to 'Now, then, we know that the planet "He was right. marvelously right. His Mars and let us see what we will find. Mars, due to its small size, is a vastly older (Continued on page 371.) ".. °

www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 315 Warfare of the Future The Radium Destroyer .r HE European War has clearly dem- will you make yourself the first Master of night the War Lord has conquered the onstrated what a tremendous p art this Planet ?" entire world and has proclaimed himself as modern science plays in the offense The War Lord promptly asks for a se- the First Planet Emperor. as well as in the defense of the contends cret demonstration of the new "Atomic What happens afterwards when the se- armies. It has often been said during the Gust," and what he sees intoxicates his cret of the Radium Destroyer is discov- past twelve months that this is not a war imagination to such a degree that he de- ered by the War Lord's enemies is an- so much of men as of machines. Noth- cides to make war on the entire world as other chapter, so we will desist I ing could be truer. In fact, it might be soon as his generals have assured him that The above may read very fantastical and said that this is a war of infernal machines enough atomic guns have been manufac- extremely fanciful. It is, however, not against more diabolical machines. tured to make success certain. And one only very possible but highly probable. It has been stated editorially in t his beautiful spring morning our War Lord Modern Science knows not the word journal that there will be war always, or finds a perfectly logical pretext to make Impossible. at least till we arrive at a period whenw war on a few nations, and the latest war some scientific genius (or shall be call dance is on. ANENT WARLIKE INVENTIONS. bim devil ?) invents a machine which at Within a few hours the first atomic gun. It is one of the anomalies of warfare one stroke is capable of annihilating one popularly known as the "Radium De- that the machinery for fighting and killing or several army corps. When that timeme stroyer,' has crossed the enemy's frontier. has been brought to its present ghastly per- arrives, soldiers, no matter how cour- The Radium Destroyer is mounted on fection not by swashbuckling, bloodthirsty ageous, will think a long time before tthey fast moving auto trucks and is controlled soldiers, but by the mild-mannered, peace - will ofer themselves to be slaughtered by entirely by Radio energy. No man is with- loving civilians, says the Review of Re- the hundred thousand. in a mile of the Destroyer -it is too dan- views. True, both army and navy officers In the meantime, probably for many gen- gerous to be near it when in action. A have exercised their ingenuity to heighten erations to come, the war death -dance will young lieutenant with phones clapped over the terrors of battle, but theirs are rather go on without any doubt whatsoever. Hu- his head and who follows the Destroyer in academic improvements on the more daring manity simply has not advanced to sue h a the "Control Auto," and who gets hi§ own contrivances of civilian mechanics and en- state where disarmament is possible. Our orders from the General .staff by Wireless, gineers. real civilization only dates back less thant guides each and every motion of the Who gave us the turreted ironclad? Not 100 years, and as human progress is ex- distant Radium Destroyer simply by mov- a naval officer, but Ericson, a marine en- tremely slow, it may take a thousand ye ing certain keys and switches in front of gineer. Who invented the machine gun, and more before humans will learn how to him. which squirts death every day on a dozen trust each other implicitly. As long as we Soon his Destroyer has arrived in front European battlegrounds? Not a colonel or require policemen and jails to keep us out of the enemy's first line of concreted steel a captain, but Hiram Maxim, a brilliant of mischief, we are not able to take c are trenches, protecting the land behind them. American mechanic. Who gave the battle- of ourselves and we cannot call ourselves In front of the trenches the ground has ship its quick -acting gun- elevating mecha- emancipated -we are still held in bond age been purposely cut up to impede the nism? Not an ensign or a commodore, but by the brute in ourselves, which threat ens progress of ordinary vehicles. The Gen - Janney, an American mechanical engineer. to break out at any opportune moment, as eral Staff, of course, knew this, and built Who invented the motors for turning tur- is witnessed in the present war. the Destroyer accordingly. Our friend rets rapidly? Not a lieutenant, but H. Therefore, the pacificists, particularly the lieutenant stops the Destroyer's truck Ward Leonard, one of Edison's former as- those in our country who think that this and moves a lever. Immediately the De- sistants. Who planned the submarine? is the "last war" and who go around shout- stroyer hops from the truck and begins Not a Hull or a Nelson, but Robert Fulton, - ing peace at any price, are not only .a so cry to jump with amazing speed over the cut an artist. in few lot, but they are cheerfully oblivious of up ground, grasshopper fashion. A So, one after another, the really impor- the teachings of history as well as of hundred feet from the well -concealed con- tant, the really epoch- making inventions human evolution. crete trenches the Destroyer is made to comprising the mechanism of warfare lieutenant moves These good people would shout murder halt. Our a few prove to be the conceptions of romantically if you dared suggest to them to dismiss switches, turns a knob and presses a key - imaginative but lamb -like private citizens. then lo ! the begins. but at once all policemen and patrolmen of inferno Usually their contrivances are anything A solid green "Radium -K" emanation perfect. They must be developed, and it their home town, but they would trust a Destroyer the strange nation implicitly from making war ray bursts from the top of the is in their development that profes- and hits the concreted steel trench. Our sional soldier has been most serviceable. on this country, simply because that nation front cover gives but a faint idea of what guns and pledged itself on a piece of paper nott to It is thus not only with the happens. The Radium -K emanation has submarines of war, but also with the tele- war I the property of setting off spontaneously phones and electric lights of peace; for the If the present war is ghastly with its the dormant energy of the Atom of any made the United its inventions that have poison shells, its deadly chlorine gas, element it encounters except lead. So States and other countries commercially bomb -throwing aeroplanes, its fire-spraying when the ray hits the trench it went up in great came not from within given indus- guns, its murderous machine guns, etc., dust, concrete, steel, men and guns behind can we tries, but from without. what expect of the wars of the it, everything. After spraying the trench Always it is a dreamy pioneer, an in- future? lengthwise for a few minutes it is gone trepid free -lance, aflame with enthusiasm, What will happen when the scientistss of completely. Only a dense cloud of vapor who enriches his country with a radically hundred years hence begin making war hanging in the air remains. new labor- saving device or way of utiliz- on each other? The fleet of Radium Destroyers now ening energy. Morse was a portrait painter Suppose that by that time our scientists ters through the gap, destroying everything when he first turned his attention to the have solved the puzzle of the atom and in their path. No gun can hit the Radium telegraph; Bell was a teacher of deaf have succeeded in liberating its prod' gous Destroyer for ere the gun can get the mutes when he began his experiments with forces. Imagine that at that time one a tom proper range, the Radium -K Ray has hit the telephone : Edison was a patentee of can be disintegrated at will, instantly into the gun or the ground below it and has telegraphs and phonographs when he gave another, what will happen? The results sent it up in vapor, including the men be- us the incandescent lamp ; Marconi was a will simply be overwhelmingly astounding hind it. As a demonstration, the Com- mere lad with a liking for physics when he and almost incomprehensible to our pre sent manding General asks that the first town conducted his first successful experiments minds. encountered, a city of 300,000 souls, be in wireless telegraphy. It has been calculated that if we couldc vacated within three hours. The terrorized With the single conspicuous exception of liberate the latent energy at present to eked inhabitants are forced to comply with the Edison not one of the inventors who have up in a copper one chit piece we would be request, whereupon a dozen Destroyers blazed new trails gave to the world devices enabled to propel a train with 50 freight line up on the hills and spray the unlucky that could be marketed at once. Develop- cars over a distance of 600 miles! city with their fearful rays. Within five ment was necessary -development by less Now, then, bearing this in mind, lett us minutes the entire city, houses, churches, brilliant intellects identified with the in- that 100 years hence some scientist bridges, parks and everything else have dustries that were benefited. invents a means to unlock atomic forces, gone up in a titanic Vapor cloud ; only a and how to control them. We can see him vast crater in the ground where the thriv- WIRELESS ON CAPE COD. stepping to the throne of his future War ing city one stood remains. The United States Navy will establish a Lord (if such still exist then), addressing After this demonstration the enemy wireless station on Cape Cod especially him in this 'fashion: "My Lord, with the sues for peace; resistance would be folly. equipped to guide vessels along the Atlantic means of my invention the world is yoyours; The country is conquered. Within a fort- coast in time of fog. i www.americanradiohistory.com 316 THE ELECTRICAL EXPERIMENTER November, 1915 When the Lights Went Out on the "Bella." By A. Troubleshooter.

QUITE a few months ago, or, to be and behold ! when this cable was traced manifested in exasperating habit of "ex- more exact, several years ago, the from the switchboard it followed the wall tinguishing" itself automatically about four writer, who for the present must use of the engine room forward toward the times a minute, more or less; usually more. the above nom de plume, had some unique front of the vessel and disappeared through Thus it behooved us to carry a large sup- experiences in overhauling the electric a tightly fitting bushing in the steel wall of ply of matches in our pockets, as it was no lighting equipment and generating plant on the engine room. At this moment it was small joke to be way down in one of the one of the numerous banana boats which thought that by simply going up to the lower decks without a light or even a ply between the port of Philadelphia and deck and re- entering the "hold" through match at night, when about 5,000 rats the West Indies. Probably a few remi- the coal bunkers that this cable would be used to hold pow -wows in the center of niscences may be of interest in this direc- in sight again of course. We supposed it the floor. tion, as the author had several quite out - simply passed through a ' -inch steel wall One of the most exciting explorations of- the -ordinary problems to contend with only, but instead it passed directly through conducted on this steamship was about the in endeavoring to fix up the electric light- a steel "bulk- head" about 10 feet thick, "steenth" visit we made to her and which ing equipment on this ship. She was built and the only way to get inside that "bulk- became necessary in order to repair the in England and answered to the name of head" was to cut a hole through the steel stern signal light, which was secured to the "Bella." shell of same. If it had been possible or rail about the deck. In order to get at the It may be said to start with, and so that convenient at the time I suppose we wire supplying this stern light it was neces- the reader will understand some of the trouble- shooters would have been at liberty sary to crawl into the sail and paint store- problems encountered, that all of the to use an oxy- acetylene flame to cut a hole room in the stern of the boat, and which wiring on this steamship consisted of a through the "bulk- head." This problem was packed full of canvas and other mis- toughly armored copper wire, which had was finally cleared up by running a cable cellaneous "junk" to within about 11/2 feet but a very thin rubber insulation of the ceiling, or, rather, the under- placed between the "central" copper side of the deck. The writer conductor carrying the current and crawled in on top of these sails and its outer spiral steel wire armor. whatnots in this instance for a dis- The dynamo room was located tance of about 40 feet. This hair - amidships in a compartment of the raising and adventurous excursion, main engine room, and from this which was accomplished by wig- point, where the switchboard was gling along on the stomach, was also located, the various circuit also accompanied by much muscu- wires and cables were led out lar exercise entailed by the necessity through holes cut in the steel walls for manipulating one of those of the various compartments a n d famous, forever smoking, coal -oit decks to different locations about torches in one hand, while in the the ship. All of these lead wires other a five pound ball -pean ham- and cables were armored, as afore- mer served to snuff out the life of mentioned, and groups of them, about 400 regular sized (4 to 6 containing often as many as 10 to inch) bandy- legged spiders, and 15 wires. were run along the steel also several dozen 12 -inch centi- hull of the boat or on the tinder - pedes thrown in for a good meas- side of the steel decks and sub - ure. This may sound somewhat decks, where they were firmly held "tame," but when it is realized that in place by means of heavy brass a bite from one of these centipedes clamps screwed fast to the steel or spiders (which thrive, of course, plates. primarily in the West Indies, where The "beautiful" job of chasing the bananas grow) means death in out a ground on one of these cir- 10 minutes or less, it will be seen cuits can be readily imagined, con- that this was "some" job. sidering that such grounds were so When the trouble -shooting "staff" common on many of our visits to first tackled this boat problem, with the steamship while she was in her numerous grounds and other port that often 15 to 20 grounds complaints, they were, needless to would be encountered and have to say, some tall land -lubbers, and it be cleared up in a couple of days very shortly became necessary for before the "good" ship sailed on the rapid expedition of the "ork its return voyage for more bananas that they pick up the language of and "grounds." the ship, such as "for'd" and "af't," Sometimes the whole group of and it was very funny at times these wires would have to be re- when some of the electricians would leased from their numerous clamps get so mixed up with the vari- for a distance of 100 or 150 feet "Electrical Trouble- Shooting on the Good Ship 'Bella' Was ous locations of circuits about the before the grounded wire itself Somewhat Exciting, to Say the Least." ship that they did not know when would be finally separated and dis- asking one of the crew for in- tinguished from the others in the formation whether they were go- bunch. It was then, of course, replaced up to the top of the engine room and along ing in the right direction or not. The by new wire, and in some cases entirely the deck, and so on up to the searchlight "staff" that endeavored to care for the new circuits were run in conduit or pipe. on the "bridge." "Bella's" diseases and complaints had a This vessel carried a good size search- Moreover, this job was not only that of large variety of experiences before they light projector on the navigator's bridge a trouble- shooting expedition, but also got finished with the job, and some of above the .pilot house and was supplied about 50 per cent. of the time was occupied these included being hoisted up the main with electric current through two large in killing multifarious and multitudinous mast in a boatswain's chair, which con- size stranded copper cables, which were myriads of a heterogeneous mob of sisted of a piece of planking with a rope se- rubber covered and also finished with a "scorpions" and "centipedes," some of cured to same at either end and which was heavy braided outer coating. These cables which were large enough to fill a soup then fastened to a single rope passed were strapped onto the steel walls of the plate. The greatest variety of poisonous through a tackle block at the top of the boat and compartments, and one of the "bugs" and other kindred animals of this mast. One of the boys really got so used largest size "grounds" ever seen in cap- character that were ever encountered in to this "bobbing tip and down" on the main tivity was presently discovered, and exist- the writer's experience were met with on mast that he could always smell trouble a ing on one of these searchlight feeders. this memorial trouble- shooting raid. All mile off, especially on a clear spring day, The ground was tested at the switch- sizes and colors of spiders, from those as and emanating particularly and only from board in the dynamo room with a magneto large as a 5c. piece up to those Y2 foot in one of the "signal" lamps at the peak of and, of course, no great trouble was diameter were frequently met with in our the mainmast. thought to be in store for the "trouble- travels about the boat, especially at night, To cap the climax, and because the shooters," as it was thought possibly the when we often explored the cavernous trouble- shooters had not finished up, all cables had by electrolysis become grounded depths of her hold by the scintillating il- of the circuit troubles on board on one of at some point along their course. But, lo lumination of a smoky Coal -oil torch, which (Continued on page 373.)

www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 317 What the Housewife Should Know About Electricity. By L. Shaw, Jr. WANT to buy an electric fan," said are "wound" to take either alternating or Incidentally I had been demonstrating a the young woman with a sweet direct current, it is more common for such large festoon to a prior customer, but they « j voice and smile that blended per- apparatus to be made to work on one or were of the battery type. I was unscrew- fectly. the other current. Knowledge of the volt- ing the bulbs with the intention of replac- The salesman was equally affable. With age is absolutely essential in both instances ing them into the box and laying them a reciprocative smile retorted: cited. near by for the next customer. Without the "Yes, madam, 'A. C.'or 'D. C. ? "' As it is probable that the reader of this least opportunity to make intelligent in- The radiant countenance changed as if magazine is of the mere male sex, the quiries as to the type of lights she wanted by magic to one of perplexity, which was writer humbly suggests that his audience my lady, with the breezy ways, in a Napole- plainly evident by the intended purchaser make an earnest attempt to enlighten his onic fashion pointed to the battery festoon nervously biting her lips. mother, sister or wife (or intended spouse) to which I alluded, threw down an en- The salesman's query resembled much with a few simple, common facts about the graved visiting card, flew out of the store the ever -mystifying technical phrases of general uses and application of the electric and before I had time to realize it the the family physician. current common to the household. limousine had disappeared.- I obeyed her The lady in question realized that she In order to show how much enlighten- commands, sending by special messenger 12 should have been versed in the matter of ment is necessary another case of no less (eigit- light) festoons. My only guide be- buying an electric fan, but being probably import than already cited is recalled to the ing he command and the daintily engraved the first one she had purchased, ac- card upon which was scribbled: "12 counted for ignorance on the sub- festoons" ( whoever wrote it had ject. However, it calls to mind one found out at least that they were clear and important fact: That since termed "festoon "), but liad apparent- the use of electricity has entered in- ly forgotten to write the voltage and to the household something in a left it to the discretion of the sales- primary way should be learned about man. Even the mist intelligent dis- it. Ignorance or indifference may cretion used is sometimes miscarried. cause much annoyance and often In this instance it might have been fatal results. that the lady wanted the battery type The average housewife has an infor her country home, where oil sight as to the workings of her sew- lamps were still in vogue. Or she ing machine and a general layman's might have desired to present them knowledge about coal gas; then why to a friend or relative not so for- not know a few simple imperative tunate as to have electricity in the things concerning electricity? house. Automatically the second question To make a long story short. the arises: "What should the housewife 12 battery festoons were returned the know about electricity ?" The inci- day after Christmas, every lamp of dent of the electric fan answers one which was completely burned out, quell. The kind of current supplied accompanied by a curt note, criticis- to the house, whether it is "alternating quite openly the fact that the ing current" ( "A. C. ") or "direct writer was not a mind reader and current" ( "D. C.") should be known. adding insult to injury by demand- The next essential thing to know is ing a credit for the goods, also gent- the "voltage." ly reminding that the Yuletide in a Taking chances is poor policy Fifth avenue mansion was complete- where electricity is involved. This ly and wantonly obliterated. On was only too well realized by the Fifth avenue, as might be known, woman who bought a 110 -volt fan 110 volt current is used. Merely as and connected it to a 220 -volt circuit. a matter of courtesy my firm adjusted The fireworks which resulted af- her claim, although it can be clearly forded much amusement to the chil- seen that the breezy limousine lady dren and the maid who witnessed was too busy and indifferent to see the display on a date that was no- that she gave an order correctly. It where near the fourth of July, but The Lady From the Limousine Gave Me an Imperative Order is even more important where a to Send "Is Festoons Like Those," Without Even Think. the husband who paid for the fan ing of Voltage, and Disappeared Forthwith. hasty delivery is desired, to make did not seem to think it such a funny sure that an order of this kind is incident. properly given. Voltage and kind of current are im- mind of the writer. The electric meter or the label on an perative bits of information to one who About two Xmastides ago, during the ordinary electric lamp will quickly deter- would purchase any heating or electro- rush so common at that time of the year, mine the kind of current and its voltage. mechanical appliances, such as the former, a lady whose limousine and livery which A few brief intelligent questions at time an electric stove, percolator, sad iron, stood outside and general appearance be- of purchase and studying printed matter, soldering iron, or the ordinary Mazda spoke of money and culture, stepped to the which often accompanies such purchase. or carbon electric lamp. In heating de- counter where I happened to be assisting will often obviate considerable inconveni- vices the kind of current is not so essential during the holiday rush and in apparent ence and perhaps accidents-often fatal. as being versed as to voltage. The latter hurry picked me out and demanded in a So get busy Mr. Man and tell the women is important. In the second instance, while very pompous manner that she wanted folks something about electricity. It may there are electric fans and vibrators which some "Christmas tree" lights (festoons). =a VP von motley. COMPARATIVE COST OF CANDLE six candles of the ordinary commercial MARCONI PLANS CONTROL OF AND ELECTRIC LIGHT. types. Four were tallow and two were AIR. sperm. They varied from 4.875 inches to Engineers of the New York Edison Co. 5.75 inches in length, and were from 0.75 Wonderful stories are being whispered have recently concluded a series of tests to 1.125 inches thick. Three cost one cent of a new Marconi invention. It is de- showing the comparative costs between each, two cost two cents each and one cost clared the inventor of wireless telegraphy candle light and electric light. In spite of 3.5 cents. has found a way to utilize Hertzian waves the fact that candles may be purchased as One of the one -cent candles burned 2 in such manner that aeroplanes can be cheaply as a cent each, this is the most ex- hours and 22 minutes, another burned 2 brought to a standstill and held immovable pensive illuminant available. hours and 24 minutes, while the one -cent in the air. Experiments ,so the report One cent will furnish 2.68 candlepower - sperm candle lasted 3 hours and 47 minutes. goes, have been conducted with great se- hours of candle light. For the same money The two -cent tallow candles lasted 4 hours crecy until the invention has been perfected and using the drawn -wire Mazda lamps 120 and 24 minutes and 5 hours and 81 minutes, and soon will be in use. The mind picture candlepower -hours may be obtained, while respectively. The 3.5 -cent sperm candle presented of air machines held stationary the recently perfected gas -filled lamp will lasted almost 9 hours. The cost of elec- in the air while guns of the enemy below give 192.3 candlepower - hours. tricity was computed at 8 cents per kw: were shooting them to pieces offers a new The figures are the result of tests with hour. thrill of horror for followers of war news.

www.americanradiohistory.com 318 THE ELECTRICAL EXPERIMENTER November, igi5 Something About Selenium SELENIUM is one of the most puz- "selene" (moon) ; this being the result also Webb, Clausen and Bronck, Mercadier and zling elements known to the scien- of the striking similarity of the properties Fritts. tific world, due to its extraordinary of selenium with those of tellurium, The two cells to the extreme right and property of varying its electrical resistance which is a term derived from the Latin left are modifications of Shelford Bid - when exposed to light. This phenomenon "tellus" (earth). It is a metallic element of well's cells; the one in the upper left -hand has been known for many years, but the the sulphur group and has neither taste commercial application of this property nor smell. It melts at 212 degrees Centi- possessed by selenium has not been prop- grade, and if allowed to cool rapidly erly appreciated up to the present time. from its molten state it forms a brown ámorphous mass, and in this condition it is a high -class insulator ; it is said that a small stick represents a resistance equivalent to a wire stretching for about 250,000 miles. The reddish vapor produced by boiling selenium, which has a decided smell of radishes, is exceedingly poisonous, and care should be taken when experimenting with it when it is in this boiling state. In commercial form, selenium exists in sticks resembling a gray sealing wax, and if it is to be used for making selenium cells it must be chemically Fig. 1. Several Specimens of Successful Selenium Cells. pure. It is the purpose of the writer in pre- Selenium cells are usually made by paring this article to make known the winding two bare conducting wires side by properties and enumerate some of the use- side around a piece of mica, slate or por- ful applications of selenium, which un- celain and coating them with a thin layer doubtedly will be valuable to the readers of selenium. An excellent description of who are interested in s&entific research, how such a cell is made is given in the Fig. z. Efficient Form of Selenium as there is a promising field for the use August, 1914, issue of this journal. Such Cell Which Is Mounted In a of this marvelous element. cells vary in resistance from 2,000 ohms Glass Tube. This peculiar substance, discovered in or more in the dark. This depends mainly 1817 by Berzelius, an eminent Swedish upon the thickness of the selenium coating corner is the Ruhmer tube form of the scientist, is a by- product from the distil- and the amount of light acting upon it; Bidwell type. The one to the right is a lation of sulphuric acid from iron pyrites also upon the very important annealing of Giltay cell. The four tiny ones shown against the white background were I! made by Mr. Webb, AUTOMATIC SWI CH ®I which are also forms of . Bidwell's SQLENIUM Crll . ARC CIRCUIT cell, while the center one is of t h e Fritts gold -foil flat /BATTERV type, which is ex- kill- 111111 DYNAMO tremely sensitive. RELAY,_ William J. Hammer I1I'I'I'I'I'I'L 3 has patented an exhausted cylindrical cell made of quartz, so as to allow the ultra -violet rays which will not pass 1j1:t -4) through the glass to readily affect t h e D1'NAMO F I INCANOESCENT LAMPÇIRCUIT selenium, which is coated over the sur- 1111111 AUTOMATIC SWITCH f ace of a copper -_-- i ,1111111 ATTERV tube mounted on a RFLAY central support; selenium Sr ruiiM frl I over the I1I1I1I110I0l is a thin tube of metal such as aluminum foil, thin enough to allow light to pass through. The copper and aluminum AUTOMATIC GAS BURNER connect to the two JfI ENIUM CELL electrodes.

l A very sensitive selenium cell w a s = J BATTERY made by Samuel RELAY Cohen, and is illustrated in Fig. 2. It consists of a num- Fig. 4. Scheme for Turning On and Off Street Lights by Means of Selenium Cells, as Devised by William J. Hammer. ber of circular metallic discs separ- (a sulphite of iron). The proximity of the cell. In Fig. 1 is shown an illustration ated by mica, and the sides are coated with the earth and moon suggested to Berzelius of a number of types of selenium cells, in- a thin coat of selenium. The complete the name "Selenium," after the Greek cluding the Bidwell, Ruhmer, Giltay, unit is placed in an exhausted glass bulb

www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 319

as shown. A small concave mirror is light is brought near the selenium the re- perhaps result in a tragic accident. On placed behind the cell for concentrating sistance drops, thereby allowing additional the other hand, let us suppose that such a the light at the rear of the selenium sur- current to flow through the windings, device as above described were installed face. which attracts the relay armature and in turn closes the secondary circuit. This is the fundamental circuit of most devices which are operated by selenium, and the principle holds the same as in this case. A very interesting and practical application of this element is in the automatic lighting and extinguishing of street lamps. Fig. 4 shows a schematic arrangement which has been actually demonstrated by William J. Hammer. This scheme he submitted in 1886 to the convention of the Edison Association of Illuminating Com- panies at Rochester, N. Y., during a discussion upon "Metering Versus Contract Systems." Such a method of utilizing selenium cells to control relays and magnets, which would turn off the gas lights Flg. 6. Selenium Cell Applied to Safety Stop for Railroad Trains. Having thus briefly glanced over the properties of this element and certain types of cells, we are now ready to consider some of the commercial applications of the selenium cell, some of which already have ' been worked out in actual practise. Fig. 3 depicts the general connection of a selenium cell, battery relay and its sec- Fig. 8. Circuits of Gas Lighted Buoy Con- ondary circuit The selenium cell is controlled by Sun's Rays Affecting nected in series with several cell batteries Selenium Cell. and a relay. As soon as the cell is placed rig. 3. Standard Connections for Selenium on in the dark its resistance is increased, con- Cell and Relay. the train and a searchlight placed about sequently decreasing the current in the G00 yards before the block. Now, when on the approach of day and turn them on the train passes this lamp it will immedi- again at night, would solve the problem of ately cause the selenium cell to close the METHOD OF OPERATING employing a squad of men necessary to relay, thus ringing the bell, which would IRON SHUTTERS ON BUILDINGS. do this work at present. be an announcement to the engineer that Two other applications of selenium de- the signal block was being approached. vised by the same inventor, similar to the Of course this particular scheme would be RELAY device just described, are an automatic used only nights. In this way some fatal window shutter, illustrated in Fig. 5, that accidents might be avoided. A more elab- 1111101 will close the shutters at night and reopen orate device was devised by Mr. Hammer, n.,.r them in the morning automatically, and a whereby a bell was rung, the whistle blown very striking u s e and the brakes set automatically when the of selenium in semaphore and signal light showed that t h e protection o f the line was blocked. His system is ar- safes, storage ranged to operate both night and day. A rooms, etc., where system of this nature is very practical and, liii the selenium cell if properly developed, will undoubtedly is so placed in the prove quite successful. room that whoever Still another practical application of the YlOwwl enters with some selenium cell has been made by the late I.l illuminant will be Ernest Ruhmer, of Berlin. Germany, in detected by means connection with of the cell. Thus, a Pintsch g a s if a burglar should buoy. A large enter the apart- number of ment the l i g h t these h_ve been from his lantern built containing will be caught by a supply of the cell, which will compressed gas actuate a bell sig- which would nal, thus giving last for one an alarm, en- month. But it abling the police was necessary to surround t h e to burn these premises. lights day and Automatic sig- night, it be- naling to engineers ing impracti- on railroad trains, cable by reason readily be Fig. 7. Complete Gas of distance etc., can Buoy With Sele- the accomplished b y nium Cell Control. at which they the proper use of were placed selenium cells, and Fig. 6 depicts such a and the fre- device which consists of a searchlight placed quency of t h e some distance away from the signal block. storms, etc., to The apparatus on the train constitutes a turn off the selenium cell, placed as perceived, with a gas so that it relay properly connected in series with would not burn Fig. to. Special Selenium some source of current, and a bell or any during the day. Cell Device for Timing other signaling device. Now let us sup- Mr. Ruhmer, Photographic Shutters. Fig. s. Two Schemes for Opening and Closing pose the train, traveling at a high speed, however, placed Window Shutters at Sunrise and Sunset his selenium cells in the top of by a Selenium Cell. approaches the signaling block. The en- one of gineer's attention, for some reason, is such a buoy, connected with a switching relay coils. The secondary circuit is there- drawn away from the block, which shows device which, as soon as the sun rises in fore open, but as soon as some source of a distress signal. This negligence may the morning, causes the selenium to reduce

www.americanradiohistory.com 320 THE ELECTRICAL EXPERIMENTER November, 1915

its resistance, thus causing the mechanism Prof. Barnard, of Lick University, em- instrument for measuring time intervals. to turn off the gas. It is again turned on, ployed experimentally a selenium cell as A small circular brush is placed near one due to the increase of resistance of the a device for automatically detecting end of the belt for removing the snow as the belt is slowly revolved by the pulleys. AUTOMATIC INDICATOR AND RECORDER OF The complete apparatus is placed outdoors TIME AND DURATION OF SNOW STORMS. with the exception of the recording device, which in this case is the chronograph. The drums are now started. As long as it LIGHT snows, the snow upon the slowly moving REVOLVING BRUSH belt will reflect the light produced by the 4t,,.. electric bulb upon the selenium cell and in 1I':I7'IfI 1P1F s /, turn indicate on the chronograph, and as '111iBf:fT7ls1'LT ; ;!- soon as it stops snowing the black surface of the belt absorbs the light, thereby pre- .fr_ venting the selenium cell from obtaining sufficient light ; consequently it will not show upon the scale of the recording in- 'kIIIIIIIIIII ELECTRIC strument. Such a device is very practical, BATTERY CHRONOGRARR as it will show exactly and accurately the time when it snowed and how often it ELENIUM CELL snowed during the night, it being a simple matter to keep the record during the day- time. At present there is available for the ENDLESS APRON Weather Bureau only an instrument which DEAD BLACK MATERIAL measures the depth of the fall of snow in to Fig. 9. Selenium Makes a Successful Snow -Fall Recorder. a box protected from the wind prevent drifting. cell, by the approach of nightfall, or also, comets, and ''.linchin has employed the A very striking experiment has been if so desired, in the case of darkness due selenium cell quite extensively in his astro performed with selenium by S. Cohen in to a storm or fog. A buoy containing suffi- nomical investigations. recording the speed of photographic shut- cient gas for one month could thus be A very ingenious device, using this ters. The apparatus is shown in Fig. 10, made to do actual service without re- wonderful element for recording elec and virtually consists of two selenium charging from three to five months. Such a buoy is shown in Fig. 7. Mr. Ruhmer told Mr. Hammer' that upward of 100 of 0000000000000000000000 these buoys had been made and had given 00000000000 excellent satisfaction. 000000000000000000000 circuit, as 0000000000 The arrangement of the orig- 0000000000000000000 inally devised by Mr. Ruhmer, is shown in 0000000000 00000000008 Fig. 8. The voltmeter needle A has been 5 W MMoon. 5 M DYNAMO HAN< oF replaced by the relay. B, B are two large ACETYLENE GENEPATM 3 Fl AME LAMP SFLrNIUM l- INCANDESCENT LAMPS. "sucking" solenoids for operating the gas TT R valve. A single dry battery is interpolated Sr;u_ in the selenium cell circuit as usually employed. will last years This battery for AVTOMATIc and, with its relay, is placed in the bottom MOTOR STARTER of the buoy and arranged to be absolutely waterproof. ,InrNll' 1111 Sir William Crookes has constructed an Fig. ri. Arrangement as Used by Wm. J. Hammer for Controlling a s Horsepower Motor exceedingly interesting type of his well - by a Wave of the Hand.. known radiometer, in which he has coated the revolving vanes on one side with trically the amount of snowfall which oc- cells, properly compensated with a Wheat- selenium and on the other with chromic curs during a certain period of time, was stone bridge and galvanometer, whose acid. He found that the white light from devised by Mr. Hammer and is illustrated needle is placed upon a chronograph cylin- a sperm candle repelled the selenium, in Fig. 9. It consists of an endless black der having a proper scale divided in frac- while the yellow light of the wax candle belt or conveyor, mounted on two ree s tions of a second. The operation of this device is as follows: The Wheatstone bridge is very finely adjusted and a light from an incandescent electric lamp is placed near the shutter ; the chronograph is started and the shutter is released. The small amount of light which passes through the shutter acts now upon the selenium cell, thereby reducing its resistance and in turn unbalancing the complete circuit. Momentarily, in turn, it deflects the galvanometer pointer. This is recorded upon the scale of the chronograph. The time is then read by the length of the line made by the needle. This device has been worked out in practise and it is another achievement in electric speed indicating devices. Still another wonderful experiment was performed with the selenium cell by Mr. Hammer at the joint meeting of the nmerican Institute of Electrical Engineers and the American Electrochemical Society, April 17, 1903. The amazing feat accomplished by him was starting and stopping a five -horsepower electric motor by a mere wave of his hand in front of a selenium cell. The apparatus used in this Flg. 12. Selenium Cell and Auxilllary Apparatus for Laboratory and Lecture Demonstrations. experiment is shown in Fig. 11. It con- repelled the chrome, thus indicating the and forming the bottom of a box as de- sists of an acetylene generator supplying gas to a burner placed before the cell, as relative absorptive powers of the different picted. A selenium cell is placed above with a relay substances for rays of different refrangi- this belt and is connected with a suitable shown. The cell is connected bility resulting in mechanical motion. battery and an electric chronograph, or (Continued on page 373.)

www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 32I Wireless Telephony Now From Washington to Honolulu. THE most wonderful feat in wireless tary Daniels said: Signal Corps of the army, representatives telephony was accomplished on the I am pleased to announce the success- of the technical and operating departments night of Sept. 29 last, when the ful outcome of experiments which have of the Navy Department and a few other human voice was projected through the been carried on for the last few months by interested parties. ether from Washington, D. C., to Hono- the American Telephone & Telegraph "A fter this successful demonstration, lulu, a distance of 4,900 miles! Company and the Western Electric Com- conversation originating in New York

Views From Left to Right: Dr. Lee de For- est in His Laboratory. Dr. de Forest Holding One of His New Regen- erative Audion Bulbs of the Type Used In 4,901) Mile Radiophone Talk. Top Right: Shows Mr. Theo. N. Vail, Talking From New York to San Francisco by Wireless (via Arlington). Bot- tom Right: Progression From First de Forest Audion Detector at Right, to Latest Oscil- lation Tube Generator at Left.

Only a few hours earlier wireless tele- pany in co- operation with radio stations City was transmitted over the land wire to phonic communication had becn established under the jurisdiction of the Navy Depart- Arlington, there automatically connected to between New York City and San Fran- ment by which long -distance wireless tele- the radio transmitter which carried the cisco, a distance of 2,500 miles, which was phony has been made possible. voice to Mare Island, where it was clearly heralded as an epochal innovation. Speech has been successfully trans- and distinctly received, and answers and Secretary of the Navy Daniels has an- mitted from the Arlington rad`.o station to other conversation were from there trans- nounced the successful transmission of the radio station at Mare Island, Cal., and mitted over the transcontinental line to the wireless telephone messages from the there successfully received, thus making originating office in New York. United States naval radio station at Ar- possible conversation without wires over "The conversation was carried on by the lington to the naval radio station at Mare a distance of approximately 2,500 miles, president of the American Telephone & Island, Cal., a distance of about 2,500 miles. the first time this great distance has been Telegraph Company. Mr. Vail ; the vice - All that was necessary to carry on this covered by wireless telephony. In the president, Mr. Bethell, and Mr. Waterbury, transcontinental wireless telephone con- first experiments the voice was success- one of the directors, while at Mare Island versation, he said, was to connect were officials of the Navy Depart- the receiver and transmitter appara- ment, John J. Carty, chief engineer tus of the special telephone outfit of the American Telephone & Tele- with the radio apparatus and send the graph Company, and representatives message. of the Western Electric Company. Captain W. H. G. Bullard, U. S. N., "Every official taking part in this who is in charge of the Arlington demonstration is enthusiastic about station, and other officers of the navy the results and the possibility of de- conversed with officers of the navy veloping this system as an extension on duty at the Mare Island yard in of the telephone system to ships at San Francisco. sca. The fact that the voices can be The demonstration was the result started on a land wire and auto- of experiments that have been in matically transmitted to a voice radio progress for some time, and their transmitter holds out hope that per- success is expected to have a revolu- sons should readily be put in touch tionary influence on communication by telephone with others at sea between American naval vessels and through some central transmitting shore stations. By means of this station. perfected apparatus, which probably "The use of such long distance will be installed at all naval radio wireless telephone communications stations, it is expected that officers in naval or military operations is of the navy on land will be able to Radiotelephonic Range Chart, Showing How Speech Was still in an undeveloped state, but it Flung Through the Ether, 4,900 Miles From Washington carry on wireless telephone conver- to Honolulu, Corresponding to Distance Between Seattle is expected valuable use can be made sation with officers at sea. Captain and Yokohama. of the wonderful demonstration ; but Bullard stated that the apparatus aside from such considerations the had been perfected to the point where a fully transmitted by radio to Mare Island department and its officials feel prowl that person on shore might carry on a long dis- from Arlington, the return answers and they have been interested co- operators in tance wireless telephone conversation with communication being made over the trans- the first practical development of this last a friend on a transatlantic liner in mid - continental land telephone line. This was march in the wonderful science of radio ocean, whenever shore station and liner successfully accomplished in the presence communication." were equipped with the necessary appar- of officials and engineers of the Western The space through which the oral mes- ,atus. Tn his formal announcement, Secre- Electric Company, a representative of the (Coxtinued on page 369.)

www.americanradiohistory.com 322 THE ELECTRICAL EXPERIMENTER November, I915 Photographing Sound Waves Electrically By Robert H. Moulton The man who has had his troubles pho- this shadow must not last longer than one- which show the waves in the process of tographing an automobile traveling at the millionth of a second. Moreover, while the being reflected from plane and curved mir- rate of 70 miles an hour, or about 100 feet light does last, it must be a thousand times rors, being brought to a focus by convex a second, will best appreciate the difficul- as strong as the light ordinarily employed lens and made divergent by concave lenses, ties faced by Prof. Albert F. Foley, of the in taking a photograph with a camera and, in fact, doing everything demanded University of Indiana, when he attempted whose shutter works at a speed of one - by the sound wave theory. to photograph a "sound wave." Pro- thousandth of a second, and it must be The sound wave is produced by an elec- fessor Foley successfully accomp, ed the turned on at exactly the right time or the tric spark gap S, which will be called the feat and, what is more, his pictur.., were sound wave will be out of range of the sound gap. The light is produced by a sharp and clear, which is something that photographic plate. second spark at the illuminator gap I, cannot be said of most photographs of Professor Foley arranged a large elec- which will be called the light gap. If the automobiles going at ftill speed. trical machine capable of producing an sparks at I and S are simultaneous the To emphasize the greater obstacles over- almost continuous stream of electric sparks light I passes S before the sound wave come by his methods, it may be stated that a foot or more in length, and each of such emerges from behind the spark terminals. photographs of racing automobiles are usu- energy that is caused a loud report. In If the time interval between the sparks is ally taken at a distance of 50 feet or more the circuit through which the sparks were any considerable fraction of a second the and the cars, of course, may be plainly to pass he made two spark gaps or breaks sound wave at S passes out of the field seen, while the objects photographed by and in front of the first gap, nearest the before the light from I reaches S. But this scientist were only 2 feet away from electrical machine, placed his camera con- when the interval between the two sparks the camera and are moreover invisible to taining the photographic plate. is properly timed the sdund wave at S the naked eye. The action that results when a spark casts its shadow on the photographic dry His method of photographing sound passes through the circuit may be described plate P. waves was suggested by the "twinkling" as follows: At the first gap the spark gen- The spark gaps S and I are connected light of the stars, a phenomena caused by erates a sound wave directly in front of in series to the spark knobs K, K0, which the light passing through air layers of the photographic plate. receive sparks from T, To, the terminals varying density, due to varying tempera- By the time that the sound wave has of a large electric induction machine hav- ture; in reality the light of the stars is traveled outwards a few centimeters from ing four rotating mica plates 30 inches in absolutely constant. In like manner sound the source the second or illuminating diameter, driven by a variable -speed elec- waves in air are waves of condensation spark occurs at the second gap. The light tric motor. The length of the spark gaps

These Illustrations Taken by Prof. Albert F. Foley, of the University of Indiana, Represent Instantaneous Photographs of Actual Sound Waves. Fig. i. A Sound Wave Produced by an Electric Spark, Just Emerging From Behind the Spark Terminals. Fig. z. The Same Wave as No. i Taken .0002 of a Second After the Spark. This Illustrates How the Wave Travels. Fig. 3. A Sound Wave Produced by an Elliptical Reflector. Time .00007 of a Second After the Spark. Fig. 4. Diffraction Pattern Produced by a Cylindrical Orating With Eight Apertures. Time .00024 of a Second After Spark. Fig. s. Same Wave as No. 3, Taken a Little Later. The Original and Reflected Waves Are Symmetrical; One Divergent, the Other Conver- gent.

-tnd refraction -that is, series of regions of from this spark is refracted as it passes T -K and To -Ko is adjusted by sliding T 'arying air density. Since, then, the light the sound wave on its way to the photo- and To horizontally, or by moving K and from a star will be bent from its straight graphic plate, thus throwing a shadow of K. vertically. Glass plates G and Go, about line path when it passes through such re- the sound wave on the plate. To make 20 centimeters square, are fastened to a gion. Professor Foley reasoned that sound the light of the illuminating spark suffi- wooden bar on rod R, arranged so that it waves produced between a point source ciently intense to give a clear image on can be rotated on a horizontal axis. In and a photographic plate should cast shad- the plate the electric charge is first stored the position shown in the figure the plates ows on the plate. The only thing necessary in a large capacity of Leyden jars charged are directly between the spark knobs T then is to photograph this shadow. to a high potential, and then discharged and K and T. and Ko, thus preventing a While this sounds simple and easy between magnesium terminals placed in a spark. A quarter turn of the handle rod enough, it must be remembered that a glass tube like a short gun barrel, to direct R removes the plates and allows the spark sound wave travels at such great speed (or the light, toward the plate. The details of to pass. In practise, however, it was found 1,125.69 feet per second at 20 deg. Centi- this process are given below. best to make the spark gaps T -K and grade) that in order to secure a sharp This physicist has a remarkable collec- T. -K. just long enough to prevent sparking image of its shadow the light illuminating tion of these sound wave photographs, when the glass plates are out of the field.

www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 323

Rotating the rod then causes a spark just light "sparks." a sheet of tinfoil F with one coating con- as the edges of the plates pass through The sound gap S is in series with the nected to earth. The time interval be- the gaps. light gap I, nevertheless the spark at S tween the sound and light sparks depends To get a strong sound wave at S and occurs before the oue at I, because of the on the capacity K,, the greater the capacity an intense light at I, the sparks to the capacity K, which is in multiple with the the greater the interval. However, it is knobs K, Ko should be heavy; consequently gap I, as shown in the figure. The ca- not at all necessary to have here a variable from one to three Leyden jars L, Lo are pacity K, consists of from two to eight condenser or one made up of small units. put in multiple with each of the jars on Leyden jars of the usual type standing on One can vary the capacity K, between t h e machine itself. rather large limits Most of the work is and still keep t h e done with one addi- proper time interval tional jar connected by varying the cir- to each of the cuit in other ways. machine jars. .1 lie time interval is The knobs K. Ko increased b y de- are connected t o creasing the capac- the gaps S and I ity L, Lo; by de- through a large creasing the length commutator C. Thus of the spark gaps the direction of the T -K and To -Ko. One spark at the gaps is can vary the capac- readily changed. It ity K by 100 per was found that the cent. a n d readily apparatus worked maintain an approx- about equally well imately constant with the spark in time interval be- either direction. The tween the sound ohief effect of re- and light sparks by versing the spark merely changing the direction appeared length of the light to be a slight change gap. The length of in the time intervals this gap is adjusted of the sound and Layout of Apparatus Used by Prof. Foley in Photographing Sound Waves. by the lever arrangement L,, DANIELS NAMES NAVAL AD- advantage of our navy this mobilization of America, and first to determine dynamic VISERS. the talent and genius of our country. The wind pressure on arched surfaces by means The make-up of the Naval Advisory response of the societies invited to co -oper- of "wind funnel." Hudson Maxim, Brook- Board Inventions, the organization of ate in the great undertaking indicates the of lyn, N. Y. ; ordnance and explosive expert experts who will contribute their inventive patriotic enthusiasm awakened by this call and maker of first smokeless powder adopt- genius to the navy, of which Thomas A. to duty." ed by the United States Government. Edison is to be the chairman, was an- Personnel of the Board. The Inventors' Guild -Peter Cooper nounced by Josephus Daniels, the Secretary These are the members selected by the Hewitt, New York City; inventor of elec- Sept. 12 last. of the Navy, on societies and accepted by the Secretary : tric lamp appliances to enable direct cur- The board will consist of 23 members, American Chemical Society-W. R. Whit- rent apparatus to be used with alternating including Mr. Edison, who was selected by ney, Schenectady, N. Y.; Massachusetts current circuits, and devices for telephones Mr. Daniels to serve as the presiding offi- Institute of Technology, '90; director of and aircraft. Thomas Robbins, Stamford, cer of the board. research laboratory of the General Electric Conn.; Princeton ; president of Robbins The other 22 members of the board, who Co., where he has been the moving spirit Conveying Belt Co. and inventor of many were chosen by ballot by 11 of the prin- in the perfection of metallic electric lamp devices for conveying coal and ore. cipal scientific societies of the country filaments and the development of wrought American Society of Automobile Engi- whose members deal with those branches tungstens. L. H. Baekeland, Yonkers, N. neers- Andrew L. Riker, Detroit ; vice - of science on which the navy is thought Y.; University of Ghent, '82; in private president of the Locomobile Co.; electrical to be dependent for invention, are: practice; founder of the Nepera Chemical and mechanical engineer and inventor of W. R. Whitney, L. H. Baekeland, Frank Co., 1892, and inventor of photographic many automobile devices. Howard E. Cof- Julian Sprague, Benjamin G. Lamme, R. S. paper. fin, Detroit ; Michigan, '96; vice- president Woodward, Arthur Gordon Webster, A. M. American Institute of Electrical Engi- of the Hudson Motor Car Co. and active in Hunt, Alfred Craven, Spencer Miller, Will- neers -Frank Julian Sprague, New York the development of internal combustion iam Le Roy Emmett, Matthew B. Sellers, City; Naval Academy, '78; consulting en- engines. Hudson Maxim, Peter Cooper Hewitt, gineer for Sprague, Otis and General Elec- American Institute of Mining Engineers Thomas Robbins, Howard E. Coffin, An- tric companies; founder of the Sprague -William Laurence Saunders, New York drew J. Riker, Henry A. Wise Wood, El- Electric Railway Motor Co. and concerned City; Pennsylvania, '76; chairman board mer A. Sperry, William L. Saunders, Ben- in establishing first electric trolley systems of directors of the Ingersoll -Rand Co. and jamin B. Thayer, J. W. Richards and Law- in the United States. B. G. Lamme, Pitts- inventor of many devices for subaqueous rence Addicks. burgh. Ohio State, '88; chief engineer of and rock drilling. Benjamin Bowditch The first general meeting of the board Westinghouse Electric and Manufacturing Thayer, New York City; Harvard, '85; was called on Wednesday, Oct. 6, in the Co, and a prolific inventor. president of the Anaconda Copper Mining office of Secretary Daniels in Washington. American Mathematical Society- Robert Co. and an authority on explosives. In announcing the names of the members Simpson Woodward, Washington, D. C.; American Electro Chemical Society -Jo- of the board Secretary Daniels made the Michigan, '72; president of Carnegie Insti- seph William Richards, South Bethlehem, following statement : tution and an authority on astronomy, Pa.; Lehigh. '86; professor of electro chem- "Desiring to make available the latent geography and mathematical physics. Ar- istry, Lehigh University, and author of inventive genius of our country to improve thur Gordon Webster, Worcester, Mass.; numerous works on electro metallurgy. our navy, a short while ago I requested Harvard, '85; professor of physics of Clark Lawrence Addicks, Chrome, N. J.; Massa- Mr. Thomas A. Edison to become chairman University and an authority on sound, its chusetts Institute of Technology, '89; con- of an advisory board of eminent men who production and measurement. sulting engineer for Phelps, Dodge & Co. would make up the board. Mr. Edison, with American Society of Civil Engineers - and an authority on the metallurgy of cop- the patriotism characteristic of American Andrew Murray Hunt, New York City; per. inventors, accepted the call to duty. The Naval Academy, '79; consulting engineer; American Society of Mechanical Engi- plan adopted for selecting the members of experienced in the development of hydro- neers- William Leroy Emmet, Schenectady, the advisory board was as follows: electric, steam and gas plants. Alfred Cra- N. Y. ; Naval Academy, '81; engineer with "I requested 11 great engineering and ven, New York City; Naval Academy, '67; the General Electric Co. ; designed and di- scientific societies to select by popular elec- chief engineer of Public Service Commis- rected the development of the Curtis tur- tion two members to represent their society sion and formerly division engineer in bine; first serious promoter of electric pro- on the board. The result has been most charge of construction work on Croton pulsion for ships. Spencer Miller, South gratifying. I have received the nomina- Aqueduct and reservoirs. Orange, N. J.; Worcester Polytechnic, '79; tions of all these societies and have ac- American Aeronautical Society-Mat- inventor of ship coaling apparatus and the cepted them, and it only remains to have a thew Bacon Sellers, Baltimore, Md.; Law- breeches buoy device used in rescues from meeting, organize and determine the method rence Scientific Sehool; director of Tech- shipwrecks. of procedure in order to utilize to the best nical Board of the Aeronautical Society of (Continued nut page 36-1.)

www.americanradiohistory.com Sght THE ELECTRICAL EXPERIMENTER I3'tyvirnber, I915 Some New X -Ray Apparatus SEVERAL new X -ray apparatus have inating gas for a quenching dielectric is erating tube itself, which becomes ex- been recently developed and per- depicted in Fig. 1. This particular inter- tremely hot when operated for periods of fected whereby the efficiency of this rupter consists of a small rotary pump, several minutes or even seconds; this is electrical aid to surgery and medical men which throws a stream of metallic mer- mainly due to the rapid ionic bombardment has been vastly increased. A number of cury against contact segments. The arc acting on the Anode electrode. Various these up -to -date X -ray apparatus will be which is formed upon the break at the shapes and sizes of Anodes and tubes were described in this article. contacts is quench- One great difficulty in the generation of ed by the gas, high voltage currents by an induction coil which is sent through the chamber. A condenser, of suitable capacity, is shunted across t h e interrupter terminals. The number o f breaks per second can be regulated by varying the speed of the motor and also by the adjustment exist- ent between t he rotary and stationary segment. A highly efficient heavy current chemical transformer (really an electrolytic rectifier) is portrayed at Fig. 2. This constitutes an ordinary rectifier of this class, employing extra large iron and aluminum Fig. i. fowl u.ed Type of Mercury Jet plates immersed in Interrupter. an electrolyte of Fig. 3. Water Cooling Apparatus for Large X -Ray Tubes. or transformer for X -ray requirements lies sodium phosphate (or bicarbonate of in the device which produces the current trans- made to help eliminate this defect, but interruptions when operated on direct cur- soda may be used . These chemical formers can be satisfactorily employed none of them have proven very beneficial, rent. Various types of interrupters have until the water -cooled Anode tube was de- but of in places where drect current is required, been built for this purpose, none com- vised. This is illustrated in Fig. 3, to- them have proved very efficient. One of when A. C. is supplied from power panies' mains. gether with its water circulating appar- These large rectifiers atus. This consists of an electrically - flrQ are inserted in the driven pump built into a large water tank, primary circuit of large to which two rubber tubes are connected (3 -5 kw.) X -ray trans- from the tube, one for feeding in the formers to clip off half water and the other for discharging it. the cycle waves of the alternating current and thus produce in the secondary circuit a uni- directional or direct current of high potential. In other words, the negative pulses of current in the primary circuit are clipped off by the rectifier and pulses of positive current only are allowed to pass through t h e transformer. This does not give a true uni- directional or D. C. in the secondary, but by interposing high potential rectifier tubes in the secondary circuit before the current reaches the X -ray tube the much -desired high tension direct tube current is approximately developed. In the large machines pure direct current at Fig. S. electro- Static Type of X -Ray 100,000 volts is pro- Penetrometer. duced by a revolving Fig. 8. Serial 'rimer NA, nu Heavy Curret S:: act' for X -Ray Work. commutator of special In this way the Anode is constantly cooled design. by the circulating liquid. This scheme has he latest interrupters of the improved Another problem met with in the con- showed remarkable results in allowing the mercury jet type and which employs illum- tinuous production of X -rays is the geti- tube to be manipulated for several minutes,

www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 32 at full load. which often means 15 to '.i skiagraphic pictures which have been taken closing the circuit through the transformer. kilowatts. with different X -ray tubes. Fig. ti shows At the expiration of the predetermined .\ recent very neat instrument has heat the bare foot of a woman. Note the won- length of time the first circuit breaks, the designed whereby the penetration of the X- rays through silver is taken. It is well known that these rays do not Fig. a. Below: Skiagraph of Left penetrate this metal ap- Foot of a Woman. Such XRay l'ho preciably and conse- tographs Enable the Physician to Diag- unse a Case Quickly and Correctly. quently a "meter" for Nute That the Structure of the Bone measuring the penetra- Proper Is Observable in This Excellent tion of X -rays has ,been Skiagraph. invented. It is shown in Fig. 4, and is called technically a "Penetro- meter." This instrument consists of a standardized tapered piece of silver, mounted on a lever which is movable in front of a fluorescent screen by means of a rack and pinion operated by a small knob in front of the instrument. A small graduated aluminum scale is provided so as to show exactly the penetration of the particular X -ray measured. The distance between the tube to be tested and the Penetro- meter, at which readings are taken, is immaterial, as the radi- ance at a given distance has an even influence through the silver and aluminum; however, as a rule 12 inches from the wall of the tube allows the quickest readings. An- other instrument for measuring the penetrating power of the rays is depicted Fig. 7. The Upper Skiagraph Depicts a Sidewise X -Ray in Fig. .ï, View of a Man's Foot With Shoe On. Obserte Particu= but this is graduated in larly the Shoe and Flesh Outline; Also the Steel Brace different units and is in the Sole, as Well as the Nails. The Metal Eyelets operated and Cord Tips Show Up Plainly. This Picture Was by a single Taken 'n aQ Second, the Pool tich.g Ptaccd wire, connected to the From the X -Ray Tube. cathode terminal of the high tension machine. This is a different instrument than the one previously described, as the former depends upon the secondary derful clearness of the bones and the magnetism collapses and the large contact voltage produced by the transformer. In- fibrous structure of same; while Fig. 7 asmuch as the penetrating power of the portrays X -ray photo of the right foot of tube depends upon the voltage, this instru- a man. with shoe on, as will be readily perceived. Note the appearance of the skin of the foot in comparison with the leather of the shoe. Also observe the nails, the arch. lace tips and eyelets. This picture was taken with a % second exposure; distance between tulle and plate was 1$ inches. while the tube was carrying 40 mil- liamperes of high potential direct current. The latter Skiagraph was taken by Harry F. Ernest, the expert radiographer of the Kny- Scherer Co. The illustration at Fig. 8 is of a new X -Ray serial timer, which will be found very useful to the medical profession engaged in snaking numerous skiagraphs. The timing of such X -Ray photos is very important. The dial indicator of this new instrument may be placed on any exposure time from 1 /60 of a second to 10 seconds. The Repeating Serial Tinier is made up of an actuating mechanism which permits Fig. z. Chemical Rectifier Capable of Handling Several Kilowatts. a pair of contacts to close an electric circuit through a magnet, and remain closed Fig. 4. Comparison Style of \ Ro ment will show exactly the penetration of for a predetermined length of time, this Penetrometer. any particular X -ray tube. being accomplished by the magnet pulling We present two exceptionally good a pair of large contact surfaces together, are separated by a strong spiral spring.

www.americanradiohistory.com 326 THE ELECTRICAL EXPERIMENTER No.vember, 1915

READING ELECTRIC METERS for the film cannot be wound off until the MISHAPS ATTEND USE OF WIRE- WITH A CAMERA. exposure is made. Winding reel and shut- LESS ON AEROPLANES. The truth -telling camera has found an- ter are automatically unlocked. This elim- It has already been noted in many official other and highly practical field of useful- inates the possibility of error from for- and unofficial despatches that wireless ness. Electric meters, gas and water getting to turn the key or from turning the telegraphy is frequently used both by the meters will in future be photographed in- key before the exposure is made. The light Royal Flying Corps and the Royal Naval stead of read and and in place of Air Service. Most people are figures furnished by sometimes used to seeing wireless apparatus, very fallible inspectors a film which, whether used on board record will supply authentic con- ship or on land, includes a series firmation of the charge. This of long wires strung between method of reading will also be masts or attached to a long pole much quicker and, with all possi- in the ground. bility of error removed, a great These generally take the form saving in the time of inspectors of a single long wire on aero- and clerks as well as of consum- planes, which, when not in use, is ers over disputed accounts will wound up on a reel like the reel be effected. of a fishing rod, inside the ma- A camera for the purpose has chine. When it is intended to op- just been invented by the East- erate the apparatus the aerial is man Kodak Co., and is known as let out, the initial impetus being the "Factograph. " This novel given to it by a lead weight like camera is oblong in shape, meas- a plumb bob attached to the end. uring 4% x 5% x 121/2 inches -is Several hundred feet of this made from selected mahogany, is wire are let out, and it assumes a equipped with a high grade an- most curious shape in the air, be- astigmat lens working at f.6.3 cause the weight of the plumb bob and a simple automatic shutter and of the lower portion of the permitting exposures varying wire naturally endeavors to hang from 1/5 to lh a second -within down straight, whereas the resist- the judgment of the operator. ance of the air through which the The camera is made in two aerial is dragged always tries to compartments -the forward com- pull it out horizontally behind the partment being an electrically machine, with the result that the lighted chamber with an open- wire assumes a curve stretching ing that fits over the meter out some distance behind the ma- dial. The reading is made by chine itself, says the editor of simply placing this opening The Aeroplane, London. against the meter and press- When several hundred feet of ing downward on the exposure wire are out, the air resistance lever. actually amounts to quite a con- This one action automatically siderable strain on the reel, and turns on the light, opens and consequently on the machine itself, closes the shutter and turns off though it is generally attached so the light. The shutter with each that it does not interfere to any exposure locks automatically and How the New Electrically Lighted Meter -Reading Camera is Used. considerable degree with the fore remains locked until film for the and aft or lateral control of the next exposure has been wound into place, is furnished from two four -cell dry bat- machine. If, however, the engine stops when it again flies automatically back to teries stored on either side of the camera suddenly, and the pilot has to make a the "set" position. and supplying current to four 3.8 volt forced descent, his operations are occasion- Tungsten miniature lamps. ally complicated by the resistance of the wire, which then is apt to act something The exposure is recorded upon special, path sensitized paper; a special film or paper is like a brake on the machine's gliding supplied in the familiar cartridge form and downward, unless it can be wound up fairly is daylight loading -each cartridge carry- quickly. ing 75 exposures. In one case an officer who was experi- a passenger on a Storage space for two extra rolls is pro- menting with wireless as in machine so fitted was quite badly knocked vided in the dark chamber of the camera to the necessity for winding addition to the roll in position, permitting about owing in the wire. He was quite an experienced 225 readings to be carried within the body study of the best the camera. A small drawer is pro - flyer, and had made a of way to behave in case of an accident. In vided in front which carries six extra he had come out unhurt lamps. several such cases by the simple proce>s of tucking his feet By pressing a small button which is lo- up onto the seat and rolling himself up as cated just below the exposure lever the nearly into the shape of a ball as possible, lights may be turned on and the camera so that when the machine turned head over converted into a "flasher" for locating heels he went over with it and his feet meters or finding one's way through dark were not trapped by the front part of the cellars. machine breaking back on top of them. Special developer, furnished for the pur- he was so full the film In this particular instance pose, makes it possible to develop went on winding away in 45 seconds. It is then ready for the of his duty that he reading by the bill clerk. No printing is at the reel till the machine actually struck necessary. The spools of film are opposed the ground. He had been obliged to steady to a tiny mirror reeled up like a movie film. himself with one foot against the floor of the clerk copying the records as they are the front of the machine and wind up the mirrored. Identification of each meter is reel on the left -hand side of the machine made possible by attaching the name and with his right hand. Consequently when UO number to the meter. These are photo- the machine struck he pitched with all his graphed with the meter reading. weight onto his foot and was flung forward In residence sections, through absence of with his right arm against the front of the the household, inspectors are frequently un- bodywork, the resulting damage being a able to gain access to the meters on the a broken arm. iffe has since For contingencies cards are broken leg and Sample of Film Record as Taken by New first call. such concluded that under similar circumstances Electric Meter Camera. provided with the word "out" printed upon he is in place it is wiser to let the wire alone when them. This card is photographed it will catch meter record and the information near the ground and hope that This prevents the possibility of a double of the and break. exposure- likewise there can be no blanks, appears on the film in its proper order. in a tree or a hedge

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MASSIVE ELECTRIC GENERATOR trates one of this concern's automobiles and tried to catch the word. At "Count HOLDS AUTOMOBILE. resting nicely on a scaffold in the center two!" he would have to strike the bell The illustration shown 'herewith depicts of the stationary field frame of the gen- twice, and these commands would be re- an extra large electric dynamo built for erator. This is one of several similar gen- peated until he mastered them. in one of the great automobile factories erators which will supply the current for Then came the combinations, "two plus Detroit. The massive size of this dynamo the entire plant turning out these motor two." It required patient, laborious effort by illus- can be judged the picture, which cars. on the part of his teacher, but gradually the little poodle learned to tap the answer for any plus combination that did not exceed twenty -five in total. Whenever he erred on any particular combination he was corrected immediately, and made to tap the right answer several times in succession, after separate commands, before any further progress was attempted. Hec- tor simply learned that the command "Count two plus seven!" meant nine taps ,,f the bell, just as he had learned that "sit up" and "roll over" meant a certain act on his part. Mr. Tryon explained some of his methods and the success he has met with as follows: "To start with," he said, "Hector has perhaps no more wonderful brain than a great many other dogs, but he has had the advantage of scientific training. From observations and experiments I had long become convinced that dogs could think and reason, and I was determined to prove it. Finding Hector, like most poodles, very attentive and ready to concentrate his whole thought on every word spoken, I put forth every energy in his mental development. It became a hobby of mine, and I thoroughly enjoyed what would perhaps tax the patience of the average man. "Physiological experiments prove that the principal parts of a dog's brain are relatively located and have the same function as the human brain. Like humans, different dogs have certain well defined talents which can be developed to a remarkable extent by continued training, providing, of course, that the dog has real brain capacity. Some humans cannot learn anything, and some dogs are the same way -naturally without brain capacity." Recently Mr. Tryon has discovered that his French poodle has a lauge Electric Generator Accommodates Automobile Within Its Field Frame. remarkable faculty for reading his thoughts. Not being a student of mental telepathy, Mr. Tryon MIND -READING DOG IS A PUZZLE more than one hundred words and to obey is at a loss to explain it, but on many oc- TO SCIENTISTS. their command with the proper action, but casions he has concentrated his thoughts DECLARED by Western scientists to he showed evidence of being able to carry on a certain number and, fixing his gaze be one of the most remarkable dogs more than one idea or thought in his mind on Hector, has silently commanded him to on record, Hector, a little French at the same time. "Hec- poodle, owned by C. J. Tryon, a mining en- tor, roll over I" Mr. Try- gineer, of Arizona, has opened the eyes of on would command, and students of psychology to new possibilities Hector would proceed to of the animal mind. Only two years of age, do so. Then his master this dog has been trained not only to add, would order him to "roll subtract, multiply and divide, but also to over, sit up, shake your read the mind of his master, this being paws and bark." a n d done, as explained by Professor C.L. Ed- after a little drilling the wards, head of nature study work in Los dog would perform all Angeles schools, by the joint powerful con- acts in their proper se- centration of both dog and man. quence. Once learned, Numerous demonstrations have satisfied an act, mental or physi- skeptical ones that there is no trick con- cal, was never forgotten. nected with the evidence of the dog's men- The dog's mathemat- tal development, and investigators have ical ability carne merely come away with the conviction that, prop- as a matter of learning erly trained, the dog is a wonderful think - to distinguish and to ap- ing and reasoning animal. ply on command the It was through reading an article by words "one," "two," Maetterlinck, on the scientific mental train- "three," and so f or t h, ing of horses in Germany, that Mr. Tryon just as the had learned to conceived the idea of experimenting with distinguish between "sit the poodle he purchased in Los Angeles. up" and "roll over," or He began by teaching the animal ordinary between "pull it over" balancing tricks, and then finding Hector and "push it over." At not only attentive and obedient, but a re- the command "Count markably apt scholar, began to devote his one!" Hector would be "Hector," the Dog That Taps an Electric Bell Intelligently, It Is Said time to the dog's mental training. It re- shown to tap a bell with quired patient drilling, but the results his paw, once. At first the word "one" "count" that number. And Hector has in astounded him, for in a short time Hector meant nothing, but after being stopped on variably approached his tapping bell and was not only able to grasp the meaning of the first ring of the bell he soon took note counted the number correctly.

www.americanradiohistory.com 28 THE ELECTRICAL EXPERIMENTER November, 1915 High Frequency Currents and Apparata E\TER since 1891, on which memorable secondary winding. The high frequency former P. The vibrator X carries extra date Nikola Tesla, the wizard of current discharges take place between the heavy silver contacts and the iron armature high frequency electrical phenomena, electrodes at HF. To properly tune the of the vibrator spring is attracted by the delivered his famous lecture before the closed oscillating.circuit SCP the condenser magnet coil as perceived. Thus this vi- American Institute of Electrical Engineers C should be made adjustable as aforemen- brator performs two functions, viz., it covering his discoveries and experiments in tioned, and also the primary inductance I' serves to interrupt its own (magnetic coil) should be variable by means of a clip X. circuit as supplied with current from 110 - (TC O This permits the capacity and the induct- volt direct current or alternating current, ance of this circuit to be altered until and also it serves as a spark gap for the maximum results are obtained in the Tesla high frequency oscillating circuit CXP. coil secondary. These high frequency currents thus pro- in some cases resort is had to a com- duced are transformed b induction into pound Tesla circuit as depicted in Fig. 1B. the secondary circuit of the Oudin coil S. P A a Here the usual step -up transformer excites This type of apparatus gives a very power- the circuit SCPX. The secondary S of ful steady uni -polar C 7C CC' ,7C and discharge, and the 2 Tesla coil TO then charges or excites the current thus generated is much in use now- S second closed oscillatory circuit S'C'P', the adays for ultra -violet ray treatment, ex- final high frequency discharge taking place citation of X -ray tubes, etc. from the secondary S' of the No. -° Tesla A great many experimenters possess a coil. P. high voltage wireless transformer rated at Where a discharge of great intensity is v. kw. or more and giving anywhere from desired the usual hook -up for a high fre- 12,000 to 15,0k)0 volts at the secondary ter- EE -B,9 .1 quency outfit is indicated at Fig. IC. Here minals. For those possessing such a trans- the saine symbols refer to similar parts as former, and also for those who may be I. Diagrams For Oudin and Tesla Coil just explained, and for this Oudin coil ar- interested in building a fair -size high fre- Hook-ups. rangement one end of the secondary S is quency outfit and who can easily purchase joined to the primary coil P; the other a size field suitable transformer of the afore- this wonderful of science. the greatest end of the secondary coil is connected to a mentioned, the following data is suggested. scientists of the whole world have been brass or copper ball B. This scheme is The Tesla coil here described will prodpce busily occupied in developing and perfecting apparatus of this nature for various purposes, including invaluable electro- thera- peutical applications. wireless tclegrap'i etc. Possibly the electro- medical profes.ioli has benefited more by the discoveries in this little known field of electrical science than any other branch of workers. In this article will he outlined a few of the more interesting arrangements and types of apparatus which can be employed for the production of ultra -high frequency. high potential electric currents, and which, as is generally knoirn, can be taken through the body without feeling any appreciable pain. TI is these high frequency current,, which oscillate at anywhere from itHloniiuli to 1000,000 or more times a second, which are utilized in the many electrical stage acts touring the country and which probably most readers have seen at some time o- other. The apparatus described in thi article produces high frequency currents of th's character, and many pleasing, startling experiments can be mails therewith, similar to those shown by the stage lecturers and college professors.

. \t Fig. 1 there are outlined at A. B and C the principal hook -ups and layouts of Fig. 3. A Well Designed Tesla Coil, Suitable for Use on Vs-Kw. High Potential Transformer. apparatus necessary for the production of these ultra -high frequency currents. At d'ffcrent from those shown at A and B, 12 to 15 -inch high frequency sparks from Pi. 1A is depicted the regular Tesla coil Fig. 1. in that the secondary is placed at the secondary when excited by a trans- circuits with a step -up transformer. T. the end of the primary and not inside of former of the type just mentioned. spark gap S, glass or other high tension .ante, as is the case in the regular Tesla Besides the transformer in question. there coil arrangement. will also be required a suitable glass plate While on the subject of high frequency condenser or the equivalent made up of schemes and circuits for same. it will un- Leyden jars, and also a spark gap, doubtedly be of interest to cover one of the which shall preferably be of the rotary latest plans for this kind of work, or the type so as to be well cooled. A quenched Collins -Sanchez high frequency generating spark gap proves very efficient for this circuit, as outlined in Fig. 2. This consti- class of work. tutes the idea now utilized in a large Fig. :3 shows the appearance of the Tesla majority of the extra compact style high coil design here proposed. The base of frequency sets supplied for physicians' re- same may be made of some well -dried quirements. etc. To begin with. a small - wood. and th's had hest he boiled in paraf- size and very well- insulated Oudin coil fine wax so as to exclude all dampness. consisting of primary and secondary P and Upon this base are placed glass supporting S is made use of. The secondary, as un- rods for the secondary and primary coils, derstood from diagram at Fig. 1C, con- and this will be found to give the very nects to a metal ball or other electrode as best efficiency where such high frequency, free terminal is high potential currents are to be produced. 2. Collins- Sanchez High Frequency Gen- observed. and its other erating Circuit. joined to the primary P. High frequency The primary coil is composed of four to currents are caused to be generated and to six turns of about No. 4 B. R S. copper, condensers C. preferably of the adjustable oscillate around the circuit CXP, which brass or aluminum wire (stranded best). type. and TC the air -core Tesla trans- comprises a m'ca or other fairly high volt- and these convolutions of heavy wire are former. At P the primary of this Tesla age condenser C. a vibrating spark gap X wound to a diameter of about 121/2 inches, coil is indicated, while at S is shown the and the primary coil of the Oudin trans- spacing the turns about 11/2 inches apart.

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The primary turns are held in shape by to the condenser fra ine as in diagram, i. e., denser and primary coil clip X should be four wax impregnated wooden clamps, as to opposite end of the metal strips, so that adjusted one after the other or alternately perceived. Also a clip is provided for one the high frequency inductance will be bal- until the maximum resonance is obtained lead of the primary so that the number anced, no matter how many condenser in the circuit as manifested by the produc- of turns in circuit. and consequently the plates are in use. The number of plates in inductance, may be varied in timing up the use can be varied by simply sliding them set. out of the rack. or al o by removing one /lat-drubber * * J óroores The secondary coil may be composed of or more of the spring contact shoes, -, a cardboard cylinder 2 -1 inches long by r, Regarding the deta.ls of rotary spark gap inches in diameter. This is provided with suitable for this outfit. t icy are illustrated two binding posts at the end of same, as at Fig.:,. Any small motor operating on shown, and the winding comprises one battery, or Ile -volt current is to be tail zed even layer of No. 20 enameled or silk -cov- in driving the rotary spark disc It. Thi 6/ass ered magnet wire, each turn being spaced disc is made up in the regular fashion as from its neighbor the thickness of the wire employed for wireless sets. but the plan itself to improve the insulation. This can here advocated is a very good one, especia l- be done easily in a screw- cutting lathe. from the air -cooling po lit of view. This coil should be hooked up as per This design calls for a 1C, -inch zinc or diagram. Fig. 1A. Regarding the glass other metal disc about 0 inches in (Lame! plate condenser suitable for this 1/ -kw. and 12 spark plugs are cut into the disc size high frequency coil. and considering as detail sketch 11 portrays. These spark- that the exciting transformer is rated at ing electrodes are cut on three sides and 12,000 volts (secondary). with a frequency then the lug is bent up. All of these lugs of 60 cycles, then .OIS microfarads con- when finished should be filed off rs turtle,' ìiiiiiiiI denser capacity is required. 1f i :, -inch off in a lathe, so as to be perfectly true. I I I common glass is used in making this con- This operation. however, had best be post- I denser about 5,333 square inches of such poned until the disc is firmly screwed or Tz Top figs d glass is required. This is coated on both riveted to a central hard rubber insulating sides inches hub, as drawing sb :,ws. The spark disc is 4. Constructional Details of iz,noo =Volt with tin-foil; l's margin Glass Plate Condenser. should be allowed around every tin -foil held securely to the motor shaft either by leaf on the glass plates. If the foil can be means of a regular hub or by means of don ' the largest spark in the secondary circuit. There is appended to this article a short fibre or /1/?. Motor bibliography of the more important articles which have appeared in The Electrical Ex- perimenter on high frequency currents. and also a number of the best books available on the subject. For those vitally interested in this subject it will be well to purchase one or more of the books mentioned. A few experiments of general interest are cited below. An experiment not very well known, although dating from the time of Tesla's first lecture on high frequency currents. is that which demonstrates how a motor may be operated on one wire, and in some cases without any wires connected to it. Upon this and other experiments employing very powerful currents Tesla has taken out a number of patents on the wireless trans- missio,, of energy through space. At Fig. 6 is depicted Tesla's scheme for Bent up a one -wire motor. One terminal of a small -size high frequency Tesla coil is hooked up to a coil of wire wound on an iron core and in front of which is placed a delicately mounted metal disc, which can Cu/ out rotate upon its axis as perceived. The iYoshers F95 Detail other end of the magnet coil is connected Detoi/ A- ó- to a metal plate suspended in the air and which picks up energy out of the ether, Fig. 5. Details of Rotary Spark Gap for ,z -Kw. High Frequency Coil. presumably. When the Tesla coil is ex- made 2.1x2Il inches on each plate, then 11 hexagon nuts threaded onto the shaft. In cited in the usual way the high frequency . such plates will be necessary for this outfit. front of the revolving spark wheel are .At Fig. 4 are shown a number of details mounted two stationary electrodes, and de- which can be followed more or less ex- tail sketch A shows how the ends of these actly in making up a suitable condenser are filed down so as to correspond with P/ole suspended rack to hold these glass plates. This rack the thickness of the rotating disc elec- may be made up of wax impregnated trodes. It is well to force a few cooling l wooden pieces, and inside of saine there vanes (washers) tightly on the ends of the are placed two hard rubber strips in either stationary electrodes as indicated. A mar- Transformer side of the frame, which strips are slotted ble base is best employed for mounting the as perceived, so that the glass plates may motor and stationary electrodes with their Rotating rest edgewise in these slots, thereby reduc- upright standards. There are thus two isc. ing current leakage to a minimum. By spark gaps in series in this design. it is looking at the top view of the condenser well to have a rheostat in series with the frame it is seen that two metal strips run spark gap motor, so that the speed of saine along the top hard rubber strips and a may he adjusted, and also thespark fre- series of binding posts are mounted on frequency, in tuning up the complete high these metal pieces. From each bindng post frequency sets. P/9.6 there runs down between the glass plates a \\'hen all of these parts have been prop- brass wire carrying a spring contact shoe. erly made up or assembled and the dia- Fig. b. Tesla's "One= Wire" Motor That Works on a High Frequency Current. detail of which is shown in sketch at Fig. grain followed as per Fig. 1, there should 4. it is thus perceived how each alternate be very little trouble experienced in pro- current passes through the magnet coil. foil -leaf on the glass plates receives a posi- ducing a heavy high frequency spark 1 foot magnetizing the iron core. and the rotat'ng tive and negative charge. The terminal long or more, depending upon the adjust- disc starts to move. Thus we have a single lead wires TI and T2 should he hooked up ments of the circuit. The spark gap, con- (Continued on page 311l.)

www.americanradiohistory.com 330 THE ELECTRICAL EXPERIMENTER No`ventbsr,' Il§15 Stepping Stones for Junior Engineers OUR young boys and young men %rlio regards the initial cost of same, it is hard four miniature steel masts may be con- are mechanically and electrically to conceive' of anything more eminently structed from these metal girders, and in inclined have to -day wonderful practical and instructive. It is true that, this way a very good wireless aerial can - facilities opened up to them in order to while most boys can gain considerable educa- be made up in replica, as perceived. Such tion by reading an aerial as this would also be of good use t h e numerous for wireless demonstration sets utilizing books available the well -known coherer receptor, and par- on subjects in ticularly when these sets are used in lec- 1 which they may ture rooms and theaters where a small be interested, it aerial 4 to 5 feet high or even less will is also equally suffice. The aerial may be made of copper true that to wires No. 18 or No. 20 gauge, and a couple gain a thorough of insulators may be placed in the support- a n d practical ing towers as sketch shows. It is also pos- knowledge t h e sible to very easily build a miniature radio actual work station building to be placed at the foot of must be done the masts, as seen in sketch. in some form For the junior enzineer there is probably or other by the nothing more interesting than the wonder- student him - ful steam and electr . shovels such as were self.. used in excavating the Panama Canal, and These "step- as used throughout the country for railroad ping stones for work in clearing away hills and embank- junior engi- ments. Fig. 2 shows how one of these neers," as they may be made up very nicely from these may be called, miniature steel beams. The shovel marbe are equally well made to operate by an electric motor, and adapted for also a dry cell can be placed on the truck training the If it is desired, a -con- mind of youth - framework. speed ful embryo trolling rheostat may also be mounted on electrical, me- the truck. To make this more complete it is well a chanical a n d to place the whole machine on civil engineers. length of track as shown in sketch. With At any rate, if a little skill and care this device will prove the young stu- of unending interest to the boy mechanic- dent does not ally inclined, and it will scoop up a heap intend to fol- of dirt in short order. The forward beam low up any of carrying the scoop proper is mounted so these profes- as to rotate, and thus each scoopful of dirt sions, he will can be lifted and swung away from the truck before emptying, or it can be dumped Fig. i. Model Transatlantic Radio Station Constructed From Toy Girders. gain a practical knowledge o f into an empty freight car placed alongside train their minds on elementary engineer- how building framework, towers and other of the shovel, thus following out railroad ing matters. There are for instance, books miscellaneous mechanical parts are to be construction in some detail. Preferably an on most every concei%able subject in the fastened and laid out in order to insure electric train should be used for hauling engineering and allied branches of science, electric toys and other apparatus which can be purchased cheaply, etc.; but there probably never has been a more distinctly practical a n d self -educating device brought out for the purpose aforemen- tioned than that in- volving the use of miniature steel stamp- ings made in the form o f girders. beams and other necessary accessory parts. T h e illustrations herewith will g i v e some idea of what can be done by young boys, even 10 years of age, with these f ¡;® afi miniature steel beams F:=.- ® and accessories. 0 .e O ',-sLmvessmt4m©®orS` /-_®i -s_ are several t There large companies sup- - - o-Oa mrs,i - d plying excellent out- i.óó ` fits of this type, with G a.: which it is possible to lay out and build sky- scrapers, wireless EE towers, railroad steam and Speed Controller shovels, Ferris Fig. 2. A Realistic Steam -Shovel Composed of a Battery Motor, Some Miniature Girders, a Battery wheels, etc., in com- the rigidity and strength, which the dirt away, and in this way quite an plete replica. While the present steel pieces greatest be out - knowledge all of us should have indeed. elaborate engineering project can carried making up these miniature construction more boys. fits are quite light and also low in price as Our illustration at Fig. 1 shows how out very nicely by one or

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At Fig. 3 is depicted details of con- mass under pressure, moving electrons AUTOMATICALLY CONTROLLED struction for an elevator in a building, and under tremendous pressure at the center ELECTRIC OVEN FOR TEST- this is moved up and down in a very of gravity must become luminous and ING SHRAPNEL. natural manner by means of an electric throw off heat. Among the many varying applications of This theory would account electricity constantly being brought before for the sun as a luminous the public, and one of the most interesting body, as a source of heat, as a at this time, in view of the conflict now powerful magnet, and also for raging among the leading nations of Eu- the electrical disturbances seen rope, is an automatic toermostatic con- near the sun during a period trolled electric oven. of sun spots; and if possible This oven is for use in one of the Gov- under these conditions for the ernment arsenals in Pennsylvania for the sun proper to have a black- testing of shrapnel shells. In the testing ened crust on its surface, of these shells it is necessary that a tem- holes torn through these lumi- perature of 120 degrees Fahrenheit be nous electrons by gases would maintained continuously for 24 hours. This account for the sun spots and control of temperature is obtained by the fiery streamers that are means of a compact type of thermostat hurled thousands of miles out which makes and breaks the heating circuit. ^- s into space. If we wish to One contact point is carried by the expan- ti carry this theory further, it is sion member of the device and the other _ possible that these same little is adjustable by means of a thumbscrew ;- luminous electrons will ac- which extends outside the case. A con- count for the rings of Saturn. denser across the contact points holds the the Northern Lights and our arcing down to practically nothing. Equatorial Light. The oven is fitted with a mercurial thermometer for indicating the temperature. It NEW FORMULA IN CAL- is also fitted with a pilot lamp, connected CULATING CUR- in parallel with the heating element, to RENTS. indicate when the current is on and off. most n Probably the accurate On a continuous test for 24 hours the tem- - method of determining the perature of the oven did not vary more value of the strength of an than one degree. Titis temperature reading electrical current in absolute is shown on the recording thermometer measure is by means of the just above the oven in the accompanying Rayleigh current balance, in illustration. which the current to be meas- The oven is of especially rugged con- ured is passed in series struction and is designed to withstand hard through two parallel circular usage. The heating element is of the fa- coils of unequal radii, one of miliar type as used in electric ranges, and which is suspended from the is rated at 200 watts. beam of a balance. The distance between the planes of the coil is varied until the force of attraction between the two coils is a maximum, and the value of the force is obtained by adding weights to the other arm of the balance until its equilibrium is restored. Since the maximum force obtainable depends on the ratio ,aQ v . =A-:.7... - of the radii of the coils alone, and not on their individual Fig. 3. Making a Sky-Scraper With, Electric Elevator Out of Miniature Steel Beams. dimensions, it is only necessary to determine further the motor, together with a rheostat, switch and ratio of the radii of the coils, and this may battery, as observed. There is practically be done with great accuracy by electrical no limit to the number of different designs means. such as these which can be worked out in The constant of the instrument -that is, an excellent manner by making use of a the maximum force per unit current for small steam engine or electric motor and a the coils in question been obtained in quantity of these miniature steel beams and -has the variety of odd parts, such as gears, the past by interpolation between values of pulleys, etc., supplied with them. the force, calculated for various assumed distances of the coils, in the neighborhood HOW SUN SPOTS of the critical value for which the force MAY BE CAUSED. is a maximum. For although the general BY PROFESSOR G. W. COOPER. formulas of Maxwell and Nagaoka give As we gradually descend into a mine, the value of the force for any two given toward the center of the earth, the temper- coils, at any assumed distance, with great ature rises so rapidly that many scientists accuracy, no formula has been heretofore believe that the center of the earth is a published for calculating at what distance molten mass, caused by pressure or gravi- the force becomes a maximum. To supply tation. When we realize that the sun, 93,- this lack there is derived in a paper just 000,000 miles away, attracts the earth with published by the Bureau of Standards, en- sufficient force to hurl millions of tons of titled "The Calculation of the Maximum water on our coast line, and that gravita- Force Between Two Parallel, Coaxial, Cir- tion decreases as the square of the distance cular Coils." a formula which gives the increases we can partially realize the tre- critical distance as a function of the ratio mendous attraction at the center of gravity of the radii. The latter part of the paper of the sun. The center of gravity, like the is devoted Electric Oven With Automatic heat Control for to the development of methods Shrapnel Testing by S. Government. magnetic poles of the earth, is not station- for facilitating the calculations. The for- U. ary but is continually shifting. If electric mulas are illustrated by numerical exam- Electric ovens have been found to be 'fluid is composed of electrons, and is uni- ples and tables, and the new formolas are superior to any other method on account of versal, the electrons at the center of grav- shown to give results in agreement with the perfect heat distribution. They can be ity must be under a heavy pressure, and those derived by more indirect and labori- used for a number of purposes. such as if the center of the earth becomes a molten ous method of interpolation. enameling, baking cores, drying, etc.

i www.americanradiohistory.com 332 THE ELECTRICAL EXPERIMENTER November, 1915

ILLUMINATED STEAM CURTAIN the patient sits and also an electrical res- be operated at a power cost that is prac- GIVES WONDERFUL EFFECT AT piratory device is provided while the nurse tically negligible, ranging from two cents AT NIGHT. in the picture is seen operating this par- to five cents an hour and depending upon The illustration herewith shown portrays ticular machine. This is used as an aid in the size of hammer used. The equipment the remarkable effect produced at night by the painless extraction of teeth. All drill- investment is small, only the first cost of a brightly illuminated steam curtain, as ing, cleaning and grinding of the teeth is the tool having to be considered. erected under the supervision of a corps performed by an electrically driven drill To use one of these hammers it is only of Harvard University students, the work lifted with a flexible shaft enabling the necessary to connect the tool to the nearest having been in charge lighting outlet or wires. of Theodore C. Brown, The low first cost of of Harvard. the equipment, com- This installation was bined with the ease of employed in a wonder- operation, makes its ful outdoor show en- use advantageous and titled "The Pageant of practicable, not only Lexington.' This where pneumatic tools steam cnrtain served have heretofore been the same purpose as a used, but on a large regular theater curtain class of work whose when t he different magnitude did not scenes and tableaux make it economical to were being assembled. install an air outfit. The entire entertain- A man with an elec- ment was planned on tric hammer may b - such a large scale that expected to do about the only w ay the cur- as much work as six tain effect could 1, men working by hand. produced, it seemed, This is easily explained was by the employment by the fact that a man of a steam curtain as with a hammer strike, the photograph here - from 50 to 80 blows a Mighty "Steam" Cu rtain IIIaminated at Night. It Served for a Regular I heater Curtain. with illustrates in a minute, while the elec- vivid manner. tric tools strike from The illumination for the Lexington dentist to hold the drill at any angle de- 1,400 to 4,000. pageant teas planned by the engineers of sired. Special forms of miniature "search- These electric hammers have long since the Edison Laonl. Works of the General lights" help the operator to examine any passed the experimental stage and are being Electric Co., at I larrison, N. J., and it, in remote part of the mouth and to work used successfully by companies installing its entirety, ins nitcil the use of dozens of with ease and surety. switchboards, pneumatic tube systems, very powerful searchlights, besides a large piping. rai:ings, sprinkler systems, fire es- number of powerful tungsten lamp banks EXPLOITATION OF capes, fire doors, etc. One large contractor and other sources of electric illumination FINLAND'S WATERFALLS. tells of the great saving through the use unknown in their magnitude to the regular The Petrograd Joint Stock Company for of these tools in taking out the mortar be- theater stage. Transmission of Water Power has made tween bricks for repointing, another of application to. the Governor_of- Vyborg for using- theta in- breaking the old engine -bed ELECTRICITY AND THE 20TH permission to exploit the water power from foundations and sidewalks. Paint mills CENTURY DENTIST. the waterfalls of Rouhialasky. It is pro- use them for fires ing mill stones, ice plants Electrical apparatus is being utilized posed to build a darn reaching from one and central stations for chapping scale off more and more every day to aid our sur- bank to the other, with five passag;s of 46 condenser tubes. lu fact, wherever a rapid geons and particularly dental surgeons. In feet in width for the water currents, of a the photograph herewith is depicted an up- depth ..f e fc.'t. According to the calculations of the Finland Hydrographic Bureau, the flow of water is 42.I)0O cubic feet per second, and can be di- rected through fouour passages. The project

Old Manna! Sledge Method.

I mj+r,n,d Electric Hammer.

provides for the erection of nine aggregates of turbines of 11.1,1100 horsepower each. Electricity Aids the zoth Century Dentist. Water power is the most efficient available.

o -date electrically equipped dental operat- EFFICIENT ELECTRIC HAMMER. 'ng room in a well -known hospital located One of the special applications of elec- New Electric Hammer Method. in Boston, Mass. All articles in this tricity comes in the use of electric ham- operating room are furnished in the most mers. replacing the man with the sledge or succession of blows makes for saving, these sanitary way even to the chairs which are hammer and star drill and the air com- electric hammers are being used success- finished in porcelain and enamel. pressor with its piping and hose. fully. They operate on the reciprocating Electrical foot control rheostats are con - The line of hammers that is made by one electromagnetic system and provide a munch- cenient:y placed about the chair in which of the leading electrical manufacturers can desired implement for this class of work-

www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 333 THE v_ D_ t 31 ..ll iI Ji JI lt lt ll il IC-if 1 1f l

How to Build a Dictaphone Desk Set By Homer Vanderbilt IIE desk telephone outlined below is and if O. N. fill the holes in the cup with button. This rings Cie party at the other a first -class instrument, very novel small carbon balls (not grains) about the end of the line; and with both parties situ- ,r and new, besides being of easy and size of the head of a pin, procurable from ated at about 6 feet from the telephones, simple construction. Furthermore, the use electrical supply houses. The diaphragm conversation can be easily, distinctly and )f this instrument is different hunt the is now replaced and securely fastened and audibly conducted. ordinary telephone, in that the receiver This new method eliminates the and transmitter are not brought into tiresome holding of the receiver and, contact wi.h the party using them. above all, budding of the mouth near One may on with another the unsanitary and t sometimes) germ- party by merely placing the apparatus carrying transmitter. at a suitable distance on the desk and _ \s the current used is quite heavy. talk in the usual way without holding a large wire must be used to connect the reeeiver to the ear. the two stations toge:her. For stations The case may he constructed, as 2u feet apart No. 18 B. & S. wire will shown in Fig 1, front some hard wood, do. For a distance of 50 feet use No. such as oak, walnut or mahogany: the 16 wire: for a distance of 100 feet use base of which is hollowed out, so that No. 11 wire; for a distance of 200 feet the ringing key and contacts may be use No. 12 wire. plaeed inside. It should then be glued or screwed together, using flat head brass screws for the purpose, which A "KID CHASER" FOR will make a very neat job. The front WAGON TAIL -BOARDS. wooden piece is made as depicted in For truck drivers and others who Fig. 3, and into the two holes are are often annoyed by children stealing placed the transmitter and receiver. ride: on tail -boards, the following The transmitter is of the "Dictaphone" scheme will be found efficacious in the type, as illustrated'at Fig. 4. The case prevention of this dangerous nuisance. is built from an old watch case re- All that is required is a small spark ceiver. with the usual parts removed. coil giving 1s -inch or greater spark. The cap is placed :r a lathe and the together with batteries and controlling hole made larger with a boring tool, un- switch, which may be mounted on the Details of Dictaphone Desk Set. til it measures 1 "n inches in diameter. back of (or under) the seat of tin This increases the area of the diaphragm: the tin -foil is connected to a binding post, wagon. Two high -tension wires are car- thereby also increasing the sensitivity of the as depicted in Fig. 4. The transmitter is ried along the frame of the wagon, as I transmitter. The carbon cup. C. is made up now tested by eonnecting a telephone re- and 2 indicate in sketch. One wire is from a circular carbon rod 13 inches in eeiver in series with a battery. joined to the I inge of the tail -board or diameter and s`í inch long. Five holes are After completion and test of the trans- simply direct to a metal strip 1. A second drilled with a No. 14 drill on one face of mitter it should be placed back of one of metal strip is placed across saute at 3, and the carbon, as Fig. 5 shows. These holes the holes in the front wood piece and se- must be exactly drilled. The two faces of curely fastened by means of a brass strip, the carbon rod, IC, must be exactly parallel as Fig. 2 illustrates. The hole is then with each other, as the operation of the covered neatly with some coarse mesh transmitter is entirely based upon this screen. point. In order to do this it is advisable The receiver is of the watch case pattern and also of the low resistance type. A 75- ohm receiver is obtained and the permanent and electro-magnet removed. The coil is rewound with 1.30 feet of No. 26 enameled wire and then replaced in the case without the permanent magnet. The connections of the coil are made in the same manner as the previous winding. After this has been done it is placed behind the second hole in the cabinet front and fastened in the same way as the transmitter. A screen is put over it, as illustrated in Fig. 1. The ringing key, or "double contact" push button, which is located in the lower box, can be made in any form and no fur- Fig. i. Connections of Dictaphone Set. ther description is nee ^.sary. A bu >zer for calling is placed on the inside back of to have it turned in a lathe. The bottom the case, as indicated in Fig. 2, and also hole for fastening it is now drilled with a 2-point switch for the circuit is mounted Coil to Keep Children Off Wagon Tali- a No. 14 drill, and then some melted seal- on the as seen. spark front, Boards. ing wax is poured into it. While still soft Fig. 6 outlines the connections for two an 8-32 brass screw is inserted and the sets of apparatus. Several of these outfits this is joined to the high- tension cable wax is then allowed to cool. This finished, can be successfully used in circuit if de- through the supporting chain, as sketch in- it is plaeed in the receiver case and a car- sired. Three to four dry cells are usually dicates. bon diaphragm plaeed over it, with a sheet sufficient for each station on 50 to 75 foot Now, when the youthful joy rider mounts of tin -foil pressing on the diaphragm in circuits. the tail -board the driver can throw in the order to make contact. Test the eireuit to see Now, with the above apparatus eom- switch and the pleasure trip is abruptly that the cup does not touch the diaphragm pleted, elose the switeh and preys the push terminated. Contributed by T. W. B. www.americanradiohistory.com November, 1915 334 THE ELECTRICAL EXPERIMENTER Construction of an Inductive Tuner By Milton B. Sleeper Part II- (Conclusion) Coil Center Pieces. de is just 1.31 inches in radius 9/33 Coupling Adjustment. 30 times. The The back and side views of this unique Fig. 8 gives the size of these pieces. In inch will go in the circle just in Fig. 10. On the sa.ne turning them up, bore the 1/2-inch hole in holes for wood screws are countersunk control are shown heads flush. shaft with the handle is fastened a square the center first; then turn them on a just enough to make the screw brass tube. Inside this is a square rod. To wooden face plate which has a prevent its interfering with the secondary little mandrel to fit tightly in taw; it is bent out. The upper end, which the hole. If the hole is not ex- i, flat, has a round tube going through it actly in the center of the raiallel to the shaft of the handle. When pieces the secondary will not the instrument is assembled a rod held be concentric with the primary. Take (A) first. 'After shel- lacking and rubbing it down fasten it in the left -hand end of the primary tube with strong glue. To fit properly in the box the end of the tube must be at right angles with \--mur/o! .é-12 zf7 rr its axis. Before fitting (B) each sec- must be fitted with Details of Binding Posts. ondary tap Fig. 7. soft rubber tubing to insulate 4 tightly by the screw eyes on the end of the and protect it from rubbing. 'secondary turns in the tube (see Fig. 3). When this is done pull all the As the handle is turned the square rod taps out at the left -hand end slides in or out of the tube, because the of the coil and bind them to- rod at the top must travel in a straight gether 'with string 14 inch line, while the guides inside the primary from the coil. Leave two or keep the secondary from turning. Oil all three inches of the binding the moving parts; there is no current car- string on the taps. In (B), ried in this adjustment. between the slit and the center, Binding Posts. make a small hole, just large Fig. so. Arrangement of Secondary Coupling Lever and Knob. Referring to Fig. 7, these binding posts enough M, pull the loose ends are composed of four parts: a screw, a of the binding string through it. Now bend In laying nut the scale for the coupling hard rubber bushing, a nut and a thumb- the taps where they are bound and pull handle, score the hard rubber with the nut. The bushings must fit tightly in the the end, out of the right end of the tube. dividers. Then with a very fine brush till in the scratches with white paint. This makes the scale stand out clearly. Connecting the Taps. When the switches are all fastened to the front it is time to connect the taps. Iam5:=1Mb.'^', By all means use lugs for this. The right wti size can be obtained from Clapp -Eastham. As each one must be soldered to the wire, it is advisable to get some very soft solder which can be melted by the heat of a match. There are several kinds on the a coil with fiq. market. Start at the left of the e the compensator taps, otherwise you will the taps a little Fig. 8. Cnd Discs of Seconda y Coil. get into trouble. Cut off longer than is necessary to reach from the toles in the case; a little shellac will make When (B) is glued in plate fasten the coil to the switch. Do not take any chances them stick. The connections on the inside binding cord through the little hole. so that on finding, when you put the coils in the should be neatly soldered to the under side the taps will be held firmly to the wooden case, that the taps are too short. Slip a of the screw head. Then the nut is end. This is to prevent their breaking off piece of rubber tubing % of an inch screwed tightly on the bushing. Outside from bending back and forth as the second- shorter than the tap over the wires. Then ary is moved. The taps solder on the lugs. It is best to try this should come at the top of on a separate piece of wire, for some diffi- r When the 1%6 the coil. At the bottom of culties may be encountered. (B) fasten a connections are made (see sF L01 little brass compensator r'I piece X that will slide be- (2) Fig. 4) do the same to the other taps. ar- tween the guides inside the .., ,i `J03 primary. Put in the piece d; -- (C). Divide the taps into jr; r is three or four bundles to go through the hole in the end piece. That is all there is ttb to do with the coils at present. Cabinet Front. Fig. 9 gives the dimensions for the front. Great care must be used in laying out the holes for switch points. Always make a dent Fig. n. Hoot: -Up for Coupler. II- with a center punch first, otherwise the drill point Starting with the tap from the seventh will run over the rubber. turn, fasten it to the top switch point on They should be laid out the large circle. Go around in order until Fig. 9. Switch Lay-Out for inductive Coupler. with a Hair of sharp -pointed the last one is connected to the thirteenth dividers. First make a cir- point. Test the coil with a buzzer and connections are clamped by the knurled cle 1.34 inches in diameter. Then, by ex- battery to see that the winding is all right. thumbscrews. This makes a neat and leak- perimenting, the exact distance can be Do not touch the secondary taps until the proof binding post. found to separate the holes. If the cir- coils are fastened in the case. www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 335 Fastening the Coils. ment (see Fig. 3). If the tube and screw comparing the sounds of the buzzer the is together, ex- eyes do not line up perfectly turn the pri- order of the taps can be determined. The Now, when the case put the the sec- cept the top (look at Figs. 2 and 3) to see mary or piece (D) until they are in align- copper strip from spring of where to fasten the slide tube. First put ment, otherwise the guide will bind against ondary switch goes to the other binding the primary, secondary and small end piece the wooden strips in the primary. Read post. The strip from the spring of the (D, Fig. 8) on the tube, with the coils in these directions carefully before attempt- primary switch and a strip soldered to. the the front on ing to put the coils in; if you do not know contact of the compensator go to the bind- the center. Do not fasten ing posts left the case. The com- yet. Spread cold glue thinly on the pri- just what to do beforehand you will make at the of mary end piece and the piece (D). Press bad work of it. The secondary taps may pensator connection must be supported so the ends of the case, esti- now be joined. Move the secondary all that it will not interfere with the move- them against Then run ment of the contact. mating the distances shown on the draw- the way inside the primary. the taps under the long staple provided for Fig. 11 the in ings. Quickly, before the glue can set, put shows connections the their support, and up to the switch points. receiving circuit. two or three screws in the front -just These, too, must be soldered. Do not for- enough to hold it in position. Take the get, however, that the left -hand end goes (NOTE. -The publishers shall be pleased rod which is to go through the screw eyes to one of the binding posts on the right to furnish the names of the manufacturers X on the end of the secondary and put it side of the case. If the taps become mixed supplying Nos. 13, 14, 17, 60 on receipt of through the tube of the coupling adjust- test them with a battery and buzzer. By two -cent stamp M cover postage.-Ea.)

LIST OF PARTS. No. Name. Pieces. Material. Sire. Remarks. 1. Front of case 1 hard rubber. 731" x 411" x r'e" Polish. 2. Back of case 1 Mahogany. 7A" x 43g" x " Shellac and polish. 3. Top of case 1 Mahogany. 7A" x 51'4" x tae" Shellac and polish. 4. Bottom of case 1 White pine. 611" x 411" x y" Shellac. 6. Ends of case 2 Mahogany. 411" x 44¢" X l's" Shellac and polish. 6. Screws for case 12 Brass. iss" x 'd" diameter Round head. 7. Screws for front 12 Brass. 44" x 1/2" diameter Flat head. 8. Rubber feet for case 4 Rubber. 9. Binding-post screws 4 Brass. % long. Round head. 10. Binding -post nuts 4 Brass. %" x %" diameter Polish with emery. 11. Binding -post thumbscrews 4 Brass. ÿs" long, ?it" diameter Polish. Knurl edges. 12. Rubber bushing for binding -posts 4 liard ruhher. ias" long. Ni" diameter Polish. 13. Primary core.* 1 Cardboard. 3%" x 311 i. d., 4" 0. d 14. Secondary core.* 1 Cardboard. 3%" x 34" o. d., 3tt'" i. d 15. Wooden piece for primary 1 White pine. Ys" thick x 81 " diameter Shellac. 16. Wooden piece for secondary 1 White pine. %" thick x 3A" diameter Shellac. 17. Wooden piece for secondary 1 White pine. ié" thick x 3,4 diamets Shellac. 18. Tube for secondary to slide on 1 Brass. 611" long x 54" x o. d., h" i. d... 19. Wooden piece to support tube 1 White pine. r's" thick x f" diameter Shellac. 20. Guides to keep secondary from turning 2 White pine. 31/2" x %" x A" 21. Piece to slide in the guides 1 Brass. W' long x ijt" thick 22. Screw for above 1 Brass. W' Flat head. 23. Screw -eyes for coupling adj 2 Brass. %" eye. 24. Secondary switch handle 1 Hard rubber. 4¢" x 2" diameter Polish. Knurl edge. 25. centre piece 1 Brass. 1" x %" diameter Polish. 26. contact 1 Brass. tae" x >as" x No. 30 B. S Three thicknesses. 27. contact screw 1 Brass. %" x 7- s0 T Round head. 28. " contact plate 1 Brass. A" x iii(" diameter Polish. 29. spring 1 Brass. 1" x ?í' x '!,,, ". 30. Primary switch handle 1 Hard rubber. x" x diameter Polish. 81. " contact 1 Brass. It's" x A" x No. 30 B. S. Three thicknesses. 32. contact screw 1 Brass. %" x 2-56 T. Round head. 83. " " contact plate 1 Brass. s'," x VA" Polish. 34. Compensator handle 1 Hard rubber. 1" x 14" diameter Polish. 35. Compensator rod 1 Brass. 2" x W' diameter Polish. Slip in hole of No. 36. 36. Hard rubber tube for rod 1 Hard rubber. 1 {e" a %" o. d. x r/" i. d Fit tightly in hole of No. 37. 37. Brass centre tube for No. 30 1 Brass l'A" x %" diameter Polish. 88. Spring for above 1 Brass. 1 x ;4" x ' /e," thick 39. Compensator contacts 1 Brass. 11" x i'e" x No. 30 B. S Three thicknesses. 40. Compensator contact nuts 2 Brass ie" thick x 0-32 T 41. Compensator switch points 4 Brass. ter," x 8 -32 T Round head screws, 42. Hard rubber piece for above 1 Hard rubber. %" x 11/2" diameter Polish. 43. Screw for hard rubber piece 1 Brass. W' x 2 -56 T Round head. 44. Stopping pins for No. 42 2 Brass. ;/p" x s'," diameter.... 45. Switch points for primary and secondary 90 Brass. 14" x 6" diameter Polish. Hole i's" deep, 2-56 T. 46. Screws for switch points 40 Brass tae" x 2 -56 T Round head. 47. Lugs for switch points.* 40 Copper. Smallest size, 3i" hole 48. Handle for coupling adjustment 1 Hard rubber. 1%" diameter x W ". Polish. Knurl edges. 49. Pointer for handle 1 Brass. %" x A" diameter Polish. 50. Centre piece 1 Brass. 1i'r" x ?" diameter Polish. 51. Washer for centre piece 1 Brass t'e" x ?b" o. d. x %" i. d Polish. 52. Washer for centre piece spring 1 Brass. 1" x 34" x ' /s," 63. Square tube for centre piece 1 Brass. 2%" x %" sq. o. d., ?a" sq. i. d Polish. 64. Square rod for centre piece 1 Brass. Bent. i's" sq Polish. 55. Round tube for coupling adjustment 1 Brass. ;4" x is" o. d. x 14 i. d Polish. 66. Round rod for coupling adjustment 1 Brass. 3" x 1/2" diameter Polish. 57. Nut for coupling adjustment 1 Brass. '4" x 8 -32 T 58. Primary mire Copper. No. 24 B. S. Double silk. 69. Secondary wire Copper. No. 26 B. S Double silk. 60. Rubber tubing.* Soft rubber. ,5" i. d 61. Strip for connections Copper. 24" x 1e" x .005" 62. Support for secondary taps 1 Brass. Bent. ' /u" diameter Means, see end of article. .

HINTS TO THE AMATEUR. thrown away at a power house. was utilized may be secured by asking for a burned -out It is indeed surprising what a wealth of for making a dandy helix. The insulation "telephone bell" with magnets, at a local electrical material for the experimenter was removed by hammering on it, causing telephone office. A friend of mine secured, may be found around telephone exchanges, it to separate from the wire, or it could be gratis, an old automobile ignition spark coil local electric shops and garages. Material burned off. at a garage, and has used it for sending such as porcelain parts, magnets, wire, The center binding posts of "Columbia" message one -half mile nicely. Contributed slightly used dry batteries and many others, dry cells may be used for taps on a loose by AVM. R..COTTRELL. which will delight the experimenter with a coupler, after being cleaned by placing in somewhat flattene.l pocketbook, may often a diluted solution of sulphuric acid and GERMANTOWN RADIO ASSOCIA- be obtained for the asking. then filing the heads quite flat. TION. In one instance a wireless amateur re- The cup on the center of the "Ever- The Germantown Radio Association, of ceived a complete head set and enough wire ready" type of dry cells may be used on a Philadelphia, Pa., would like to receive a for an aerial in this way, while I have used detector for holding the crystals, while the few "sparks" from those interested in with success for six months, on my 1 -inch wax on the top of dry batteries may be radio work. The club is now located at spark -coil set, dry batteries which were dis- remelted and cast in paper molds to make 5801 Germantown avenue, Germantown, carded from an automobile. A No. 8 B. a variety of knobs. Philadelphia, Pa., and meets on the third & 'S. covered line wire, 'which had been Enough magnet wire for a loose coupler Monday of each month.

www.americanradiohistory.com 336 THE ELECTRICAL EXPERIMENTER November, 1915 HOW TO BUILD AN ELECTRIC The voltmeter should be placed in a con- alkaline -earth metals. it is only necessary SPEEDOMETER. venient place, so that the operator may cast to heat a salt of the metal in order to ob- A most interesting application of elec- his eyes on it very quickly. On a bicycle a tain the colored flame. With all the others, tricity is represented in an electric speed- good place is on the handle bars, as shown however, the metal itself must be volatil- ometer, an instrument used for denoting in Fig. 3. ized, which can readily be performed by the speed of vehicles or any other moving This speedometer can also be used on the electric arc or spark. object. automobiles, carriages, motorcycles and any The exhibition of these various flame This type of speedometer consists essen- other form of vehicle. It is useful indeed colors is an interesting and rather spec- tially of two parts, viz., a direct- current for testing machinery of all kinds. The tacular experiment. For the metals of the generator of low amperage, which is driven calibration can be performed by calculation, first division the apparatus is very simple. aided by a common hand speed indicator. An alcohol lamp, which can be easily made A small telephone magneto serves very well out of a small bottle, a cork, a metal tube for this stunt, but then the voltmeter must and a wick, is provided for each metal and be an A. C. instrument. Contributed by labeled. In the alcohol of this lamp a salt ro//me/er or.rpPedurofm/ry SIDNEY SISSELMAN. fire/,t n ghee/ AN ELECTRIC KEY HOLE FINDER. lamp For those gentlemen who are inclined to stay out too late in the evening, or rather morning, and who often experience consid- Clomp erable trouble in locating the keyhole in the front door of their domicile, the following wrinkle may be of interest: I notched out a small hole in the side of the door frame on my front door and placed in it a miniature battery lamp re- ceptacle and a small Tungsten flashlight bulb. A battery may be placed in the cellar similar to a bell battery, etc., and ordinary bell wires, preferably fished up inside of the door frame, or otherwise neatly concealed. lead from the lamp socket to a circuit closer placed under the front door mat as the sketch This circuit closer may v shows. e be purchased at any electrical supply store m and can be located under a certain corner C C f B'. of the mat, etc., so that the home-corner will possibly sooner or later place his foot Scale co/i0ro%d *d in M.f.'A:orA.M. on the proper part of the mat, and thus flash on the lamp which illuminates the keyhole. Apparatus for Testing Flame Colors of Different Dioirt. il It is hoped that this novel idea will be Metals. *n,Oaf/ of ; I I found welcome to many brother "Elks." of the desired metal is dissolved. The dynamo Some nifty stunt. Eh! what? chloride is the most convenient, both be- fig. 2 Contributed by cause it is the commonest salt and also be- ALBERT GALLAGHER. cause it is soluble in alcohol. The salt must for Bicycles. Electric Speedometer It is generally admitted that the hardest be chemically pure, for if it is not it is sure the wheel of a problem is to find the keyhole in the "wee to contain traces of sodium, whose bril- by friction or gearing from liant flame quite obscures that of vehicle, for instance, and a voltmeter con- small hours" of the morning. The writer yellow of this article presumes, evidently, that the any other metal. nected directly to the generator. The of traces of sodium in at- 1, may be an 8 or 10 rapidly oscillati Ig movement of the feet presence The dynamo, Fig. be proved volt machine. Now make the supporting mospheric dust and moisture may of two iron clamps by holding almost any object (an iron nail parts, which consist for instance) in the colorless Bunsen B B. attachable to the dynamo frame by is flame, which will be turned yellow for a means of bolts C C. The curved part D the alco- to the vehicle. moment. If the salt dissolved in used to fasten the dynamo is chemically pure, however, the flame such as a bicycle frame, tightened by an- hol suitable of the alcohol lamp, instead of being color- other stove bolt E. Any other violet, green. orange or he employed in fastening the less. will be yellow, means can deep crimson, according to the metal used. dynamo. is very striking. is next In a darkened room this A small rubber friction wheel The colored flame, when examined with a 'S. no expla- made, and it is shown in Fig. spectroscope, shows the characteristic lines nation being necessary, as all the required on the of the metal. data is given. It is driven tightly For showing the metals of the second shaft is to be placed in con- dynamo and class a series of small spark gaps are used: tact with the driver wheel. the electrodes of the different gaps being The recording device consists of an ordi- the to be examined. The is substi- made of metals nary voltmeter, but another scale gaps are put into operation. one at a time, tuted for the original one and calibrated T. multi -point hour" or by means of a suitable H. in speed units, such as "miles per switch. The electrodes should be very R.P.M., etc. The method of calibrating the so that the stand- close together, almost touching, voltmeter is as follows: Obtain a "spark -ball" may be formed. A very bril- ard speedometer and place on the driver in this way. It secure the liant flame is produced wheel, and at the same time may be examined with a spectroscope, the dynamo near the same driver and connect flame. the vehicle same as the alcohol it to the voltmeter. Now start Below is a list of the more common and observe so Electric Light Finds the Key -Hole wheel running (on a frame) metals and their flame colors: the scale on the standard speedometer. and For You. note the position of the voltmeter needle. very shortly will locate the proper contact FIRST GROUP. line, and the same spot on the mat. -Ed. Sodium, Na Yellow At that point mark a Potasium, K Violet figure as the standard speedometer is show- Calcium, Ca Orange points should be thus checked CHARACTERISTIC FLAME Barium, Ba Green ing. Various Crimson off in the same manner by running the COLORS OF METALS. Strontium. Sr When a gas containing metallic ions is SECOND GROUP. vehicle wheel slower or faster. white This device can be used as a tachometer heated to incandescence it exhibits a color Magnesium Mg t Dazzling of Aluminum, AL J or revolution per minute indicator, the one and a spectrum which are characteristic Zinc. Zn Blue point that must be remembered being to use the metal which it contains. Each of the Copper, Cu Green R.P.M. indicator as a means of 60 or '70 known metals has its own flame Iron Fee Reddish yellow a standard by B. MACKEY. calibrating. color and spectrum. With the alkali and Contributed www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 337

OLP NT The Amateur Radio Station Which Aided Uncle Sam A Complete Description of the Wireless Station of Mr. Charles E. Apgar -Full Details of the Audion Amplifier Circuit and the Inductance Coils Are Here Given By Charles E. Apgar SINCE the publication of the article gave me a copy of the latest catalogue of later a rotary, capable ..f breaking fain per on recording Say ville radio signals one of the leading experimental wireless second. Getting rather tired of hearing phonographically in the September, supply houses. Careful study of this and ..iluw's my spark ?" "I)o 1 sound better 1915, issue of the Electrical Experimenter, recalling the zig -zag lines and drawings in now'" I decided to turn in attention to so many inquiries have been received by the magazine (Modern Electrics ), to which improving my receiving apparatus. In all recourse was made. seven different tuning coil: and loose couplers, each possessing some fea- Fig. i. Top View Depicts Mr. gave .me sufficient in- special Chas. E. Apgar Receiving Wire- sight as to the require- ture, have been made (see Modern Elec- less Messages at His Wonder- ments of amateur wire- tries, January, 19I I). Variable rotary fully E f f i c i e n t Experimental Radio Station Located at West- less telegraphy to make condensers were next constructed and, be- field, N. J. a "try -out" about one ing dissatisfied with the unstableness of month later (Dec. 11, crystal detectors, I decided to try out an 1910). I shall never 'tuition during August, 1918. Having some forget with that satis- knowledge of the effects of magnetism on faction i made m_v final electricity in a vacuum. I placed a magnet connection o n t h a t near the auction, when instantly the sig- memorable evening. In nals seemed about ten times louder. Here less than one minute I was a discovery -to me at least. A new heard O. H. X (now 150 -foot steel mast loomed up, as well as W. H. B.) Seagate and other extravagant expenditures -all to one other station. Con- come from the proceeds of this discovery trasting .this with the -but a short time spent in the city library experience of some brought me to earth again. I still have amateurs (who, as I my aerial in the trees. have read, often spend The use of the magnet was continued a month or more fool- for some months with gratifying results. ing around before get- 11any, stations, with the use of a small Lower Photo Shows Mr. Apgar in ting. a single signal). horn on the receiver, could be read about the Act of Actually Recording SO feet from the 'phones. Having been a Long Distance Radio Message to say I was satisfied on a Phonograph Cylinder. is putting it mildly. Of able so definitely and satisfactorily to pro- This "Canned Wireless" Has fam- duce loud incoming signal-, the matter of Helped Uncle Sam Immeasur- course, the whole ably. ily was called in -even amplification occurred to tree. I tried out the cat -whose "meow" various types of microphone transmitters. Best me from interested amateurs and others was about as near to a wireless signal as results. though far from satisfactory. concerning many details of construction. anything I had ever heard. were obtained by a certain form of carbon and having ransmitter, using a low voltage current. circuits, etc., that I thought that possibly Having caught the fever Signals many a more complete statement concerning the some constructional ability, my, instru- from stations, when using station and the work accomplished would ments were home -made, excepting the de- his circuit after some modifications and be welcomed by many readers. Also since tector stand and silicon (purchased from the station has been so generously referred the E. I. Co.) and 'phones. After install- to in the daily and technical press since ing this set on a suitable operating table July 18, 1915, a brief history of the station and getting reasonably familiar with tun- itself will surely be of interest. ing operations. even to picking up Cape

. Not many years ago, less than five, when Cod (old M. C. C.. distant about 350 looking over a magazine in a stationery miles), I decided to look into the matter store on Broadway, New York, I noted in of sending signals. I found a single unit the back section some zig -zag lines and automobile spark coil among some elec- drawings (diagrams of radio circuits). trical junk, connected this to my aerial The magazine was immediately laid aside through some wire wound around a box with the thought: "What nonsense to and having no sending key, tapped on one print such crazy stuff which only an expert of the binding posts with one of the bat- can understand." tery wires to see if it would buzz. It did. About a month later the New York Then without knowing why, I tapped off Herald published a letter signed "Amateur" the call "B. Q.," whom I had heard send- stating that on the previous evening (Elec- ing to other amateurs. "B. Q." lived many tion night, November, 1910), he had copied blocks away, but after a reasonable time the Herald's wireless Election returns and the door bell rang and. much to my sur- knew the results of same before 11 p. tu. prise, there was B. Q. in person. Said he z. Audion Amplifier Circuits Employed in of that evening. Comments by the editor had heard me call him, and though it was Mr. Apgar's Radio Station. followed, stating that "Amateur" was a near midnight, came around to see what 1 cashier in one of Nall Street's well - wanted. This experience letl me to be- giving careful consideration to sound known banking houses; the name and ad- lieve that an efficient sending set would not resonance, could be plainly heard and read dress were also given. This was my first be difficult to make. I soon began con- all over the house. stopping place when again reaching the structing a % K. W. open -core trans- Naturally the natter of making per- city. former, also a suitable condenser. using manent records occurred to me about this This cashier soon discovered that I didn't aluminum sheets and old photographic time. I bought a second -hand phonograph. know a tuning coil from a detector, so he plates; an ordinary spark gap at first. but and on Oct. 28, 1913. made my first record

www.americanradiohistory.com 338 THE ELECTRICAL EXPERIMENTER November, 1915

of wireless; this being "press," sent out by the New York Herald station at the Bat- New Pocket Wireless Set tery in New York. Following this and One Of the latest developments in the metal tube held in the hand to the instru- until about October, 1914, many records wireless field is a small, pocket-size wire- ment proper. In some cases the tube has were made of N. A. A., N. A. H., W. C. less instrument which can be used for been placed in the ground and messages G. and other stations. By the adoption of transmitting or receiving such messages received and transmitted in this way. the audion circuit discovered by Mr. E. H. over distances of one -quarter to one -half When the metal tube is held in the hand, Armstrong, the receiving efficiency of my mile and more. This particular apparatus as shown in the right -hand photograph, it outfit was enormously increased, as well as being enabled to bring in many undamped wave stations, including W. S. L., W. G. G., N. A. A., N. B. A. and others. Interesting phonograph records of several of these undamped stations have been made. The photograph of my station is shown in Fig. 1, which consists virtually of a loose coupler, primary and secondary loading coils and three variable condensers connected to an Armstrong circuit as perceived in Fig. 2. The dimensions of my inductance coils are as follows: Primary of coupler is 10x, inches and is wound with No. 23 S. S.; the secondary is 10x4% inches, wound with No. 28 S. S.; the secondary loading coil SL is 22x31/2 inches and wound with No. 30 S. S., while the wing inductance \VI has No. 30 S. S. for its winding. The capacity of each condenser is given in the diagram. A direct current milliampere meter is connected in series with the grid circuit as shown and signals* can actually be read by observing the movement of the needle. An amplifier of my own invention is connected in place of the regular 'phones and a low resistance receiver with horn is coupled to the amplifier. The same 'phone can be placed over the recorder of a phonograph and thereby messages may be copied on a record. Fig. 3 illustrates the phonograph which has rccorded all the Sayville "secret code messages-note the telephone receiver on the reproducer. My aerial is 600 feet long, the wires Photo (C) by Underwood & Underwood. starting 10 feet apart and ending 18 inches At Right: Dr. Cox Receiving Radio Signals With Pocket Set. apart ( fan shaped) ; the average height is At Left: Showing New Pocket Wireless Set Fastened to Belt. about 50 feet. With this set I am able to as shown in our illustrations has been per- would undoubtedly be best to make a tune to 4,001) meters without any aerial inductance and if loading fected by Dr. H. Barringer Cox, of New ground connection by means of a wire con- coils, coils are is on the bottom in I re- Bedford, N. Y. The inventor himself nected up with a metal plate connected the circuit am able to one ceive stations of over 9,000 meters wave seen in our illustrations, the at the of the shoe. length. right depicting Dr. Cox in the act of re- the While the 1915, issue ceiving a wireless message by means of MARCONI ABSORBS ENGLISH September, of this his waist per- magazine has given rather a full account apparatus strapped about as POULSEN INTERESTS. of the work done at the request of Chief ceived, and the antenna consists of a hol- A syndicate representing Marconi inter- W. J. Flynn, of the C. S. Government low tube held in the hand. ests has acquired the Poulsen -Padna rights, Secret Service Bureau, probably the addi- The left -hand view discloses how the and in due course the Poulsen system will tion of a few other details will make the apparatus may be worn under the coat, and become part of the Marconi organization. account more complete. it is held in place by a belt, as becomes According to this report, an important A short time .before being asked to do evident. The 'phone and head -band can be option in connection with the British Poul- this work a business call was made on hooked in the belt very readily, and it is sen wireless rights lapsed recently, though Chief Radio Inspector W. P. Krumm at suggested by Dr. Cox that this outfit would fresh arrangements would quite possibly New York City, and during a conversation undoubtedly prove of great value for the have been made. In the meanwhile, how- on amateur plants in general he expressed soldiers in the field. He intends to loan ever, the syndicate representing the Mar- a desire to visit my station. During this his invention to the European armies now coni interests, recognizing no doubt what visit, which soon followed, the general effi- at war. Such an outfit as this can be a formidable rival the Poulsen system ciency of the station was demonstrated, worked over such distances as aforemen- would be in the future if it remained inde- also many phonographic records of wire- tioned and should prove of extreme value pendent, has stepped in and made an offer less signals were reproduced. Hence to the men in the trenches or on the open which apparently has been accepted. when Chief Flynn consulted W. P. Krumm field for transmitting and receiving orders, For the present, owing to Treasury re- about the checking up of Sayville I was etc., as the enemy would not very easily strictions, formation of a subsidiary com- called in on the matter and told to "get take notice of such a well -concealed wire- pany and other financial arrangements for busy." The work of making the records less instrument as this, even though the the completion of the deal cannot be put began each night at 11 o'clock and con- operator was in sight. The apparatus through, but after the conclusion of peace tinued for two or three hours, dependent comprises an especially sensitive detector. it may be looked upon as certain that Foul - on the accumulation of messages at the together with the usual high resistance head sen will be under the Marconi banner. Sayville station. The next morning a 'phone and a tuning coil with condenser. The Poulsen system of wireless teleg- translation of the records was made and A flexible wire joins the watch -case tele- raphy, worked out by Valdemar Poulsen, a copy of them turned over to Chief Flynn. phone receiver to the tuning coil case, and of Copenhagen, eight years ago, is said to which permitted of immediate compylrtson another flexible conductor joins the hollow be a much faster means of communication with the censored message records received than that of Marconi. In 1907 Professor by other departments needle. One of the greatest feats ever produced Poulsen also talked by wireless between of the Government. by any amateur is receiving N. A. A. 600 feet from Later on all the phonograph records made 'Copenhagen and Berlin, some 250 miles, the 'phones, which is an actual result accomplished to a were delivered to the Secret Service Bu- by Mr. Apgar. He has received the "time signals" and proposed establish wireless tele- reau at New York from Arlington in the open street, full of shade phone service to America, via Ireland. The City. trees and while noises of all kinds were in the vi- Poulsen patents in the United States are --'Zte of our editorial staff has recently wit- cinity. Of course, if these conditions did not pre- nessed this experiment with the milliampere meter. vail the signals would undoubtedly be heard at a controlled by the Federal Telegraph Co, Signals were reabable by merely observing the much greater distance.- Eotrox. of San Francisco, Cal.

www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 339

A MACHINE THAT CAPTURES of this necessity, and has conceived the CONCERNING GROUND AND HOLDS WIRELESS TALK. ingenious idea of powdering the steel disc ANTENNAE. When one contemplates the marvel of with a finely divided magnetic substance - It may be interesting for the amateur sculptured sound on a graphophonic rec- iron reduced by means of hydrogen -in the radio readers of your magazine to know ord, and realizes that from the cold vor- hope that this powder would collect along what success I am having using a ground ticity of line there may magically spring the magnetized traces left by the soft -iron antenna. the golden lilt of the greatest song voice stylus. I laid two stretches of No. 18 insulated that the world has ever heard, then comes In these conditions, although at first the bell wire directly on the surface of the the conviction that we are living in the reinforcement appeared scarcely sensible, ground in my back yard (in Boston), the days of white magic. it was possible to prove that it existed, in length of each stretch being about 25 feet. This is simply by way of introduction of a very original manner, at the wireless The lead -in was taken from the middle. a greater marvel yet -a marvel of marvels, laboratory of the Eiffel Tower station at thus forming the shape of a "T." The so to speak, regarding the reproduction of Paris. During the experiment signals from instruments I use are a single -slide home- sound. It is the application of the Poulsen Cleethorpe and from Clifden were heard, made tuner, galena detector, 75 -ohm tele- but the disc recorded only phone receiver and an E. I. Co, loading the first, which were the coil. With this aerial I receive the Boston loudest. But, after the Navy Yard and a number of stations employment of the pow- around the harbor. I had some corre- dered iron the C l i f d e n spondence with an experimental radio sta- signals were recorded. tion here regarding this "ground antenna," Our diagram shows Mr. and they advised me that this type of aerial Dosne's plant. It includes has a directional effect; that is. if it runs a wireless receiver with a due north and south, stations east and crystal detector; the tele- west cannot be heard. I advised them that phone has been removed my aerial runs directly sideways to the and replaced by an ampli- Boston Navy Yard and I receive messages fier. Finally the Poulsen right along from this station. They wrote i and told me that my not encountering di- System for Recording Wireless 'telegraph Signals on Telegraphone. telegraphone is connected, in the place of the loud - rectional effect with this ground antenna telegraphone to the writing and the record- speaking telephone, to the amplifier. is due to one of two things- either the ing of wireless messages. And as the In these conditions it suffices, to record wires are so far short of the proper length voice is now being sent over considerable a message received at an ordinary wire- that I get forced oscillations, or else there distances by way of the ether, it has to do. less station, to start the steel disc rotating are local electric wires that neutralize the in its logical extension, with the human in order that the fluctuations of the cur- actual direction of my wires. I shall be voice. rent, passing through the combined tele- pleased to hear from any amateur who Contradictory as it may seem. this new phones and miscrophones of the amplifier, experiments with this type of aerial. Con- method of writing and recording wireless may determine in the coil of the Poulsen tributed by P. J. LEARY. communication uses recordless records- apparatus a variable magnetic field, of that is, they cannot be seen and read by which the little soft -iron needle consti- any of science's aids to the eyes. A wire tuting the core of the coil forms a part. NEW ORLEANS RADIO OPERA- is the only thing an observer may see. The message is read by placing the ear TORS MAKE FINE RECORD. The Poulsen invention, you may prob- at one of the telephones of the Poulsen Complete success greeted the recent ini- ably know, is a magnetic phonograph which apparatus, which, after the registration, tial attempt of the radio operators at the records sound vibrations, not by actual behave like simple receivers and repeat the New Orleans Naval Station to flash a mes- needle marking on a plastic disc, but by message. sage to the Government wireless station at variations of magnetism in a steel disc. It should be noted that the speed of Darien. C. Z. You can note the concentric lines made by recording a message may be modified for The test message was sent at 10 o'clock the needle on a familiar musical record, repetition. In fact, the disc may be made in the morning, and Chief Operator Mc- but the steel wire used by Poulsen looks to turn at a greatly reduced speed if one Kean, of the local naval station, had no precisely the same after a song or a sen- is not well trained in sound -reading; but difficulty in communicating with the men in tence has been stored up in it. in this case the signals lose in intensity. charge of the station on the Canal Zone. Imagine a dead piece of metal, with no On the other hand, if the speed of recep- The distance between here and Darien is visual indication of how it is accomplished, tion is greater than that of record, the approximately 1,600 miles, and the oper- holding human speech imprisoned in its signals gain in power. ator on the Canal Zone stated that the sig- cold confines and music and sound vital to if nals from New Orleans were so strong as and enlightenment of the The same disc may serve indefinitely to almost affect the ear drums. the progress it is not desired to preserve the record. ! of distance world (A) Antenna. (D) Crystal Detector. The sending the long- message THE VOICE IS STORED IN MOLE- Fixed (KI) to the Panama Canal by the New Orleans CULES OF METAL. And here is a (T) Earth. (K) Condenser. Naval Station marked an epoch in Govern- Adjustable Condenser. (R1) Prime Re- radio the baffling mystery in this storage. Precisely Sec- ment circles. It means that final not ceiver. (Ml) Its Microphone. (R2) link in a chain wireless what the nature of it is man shall Its Microphone. of stations to con- are by authority, until the ondary Receiver. 0M2) nect the United States and points in the know, we told (P) Steel Plate. (B) Poulsen Coil. (S) mystery of magnetism is fully solved. Tele- tropics, as well as our possessions in the The wizard responsible for the new and Soft -steel Needle. (tl -t2) Receiving Pacific, has been completed. wonderful discovery is named Dosne, and phones. Two 300-foot steel towers and an excep- Lucien Fournier, in describing his achieve- tionally powerful set contribute in making ment, naturally speaks first of Poulsen's THE SMALLEST LOOSE COUPLER. the New Orleans radio station one of the earliest model. It was then constituted by What is probably the smallest loose best et completed. A force of 16 operators a bobbin of steel wire which was made to coupler ever built and suitable for actually will be required in handling the radio equip- turn under a receiving coil. The wire receiving wireless signals is shown in the ment when the station has been brought records speech magnetically and it is re- photograph. It is perceived resting on top up to its full strength, it is said. Most of produced in a telephone receiver when the the dispatches flashed through the air from coil that has been influenced passes a sec- the ships in Mexican and other tropical ond time under this receiver. waters are expected to be handled directly The device used by Mr. Dosne differs through New Orleans. from this early model by replacing the steel wire with a steel disc turning under a light soft -iron needle forming part of the so small that it will fit in the hand nicely electromagnetic receiver of the apparatus. without projecting beyond the fingers. It This apparatus moves from the edge to Miniature Loose Coupler Resting on Top is complete in every way. being fitted with the center of the disc during the inscrip- of Large Coupler. a primary tuning slider as well as with a tion, so that the record is spiral, like that six -point switch on the movable secondary, on a graphophone disc. of the large coupler, which latter measures accurately wound with comparatively fine The Poulsen device cannot be used for about 2 feet in length. The large coupler magnet wire. This small coupler has been recording wireless signals; the coil con- is fitted with three primary switches, and used a number of times and operates very nected with the needle planned for use as same is capable of tuning in wave lengths efficiently in bringing in wireless signals. a telephone record needs modification for up to 9,000 meters when used with a fair - It is capable of tuning in wave lengths up adaptation to the new kind of work .re- size aerial. The miniature loose coupler to about 200 meters when used with a quired of it. Mr. Dosne has taken account resting on top of the larger instrument is small -size antenna.

www.americanradiohistory.com 340 THE ELECTRICAL EXPERIMENTER Nuvetnber, 1915

HOW WIRELESS WAVES TRAVEL AMERICAN RADIO LEAGUE der very good atmospheric conditions 800 AROUND THE EARTH'S WIRELESS STATION. to 1,000 miles is not at all difficult with CURVATURE. By Frank C. Perkins. this set. The transmitter is contained in MOST people probably do not stop to The accompanying illustration shows the a polished wood cabinet, a corner of which consider what a great depth of equipment of the American Radio League may be seen in the extreme left of the earth exists between two modern relay wireless station. This station is in picture. I,wng distance radio -telegraphic stations operation at New Rochelle, N. Y. The There is a special loose coupler used for aerial is of the inverted waves up to 3,000 meters or a little over. "L" type, having an aver- This loose coupler has a very long sec- age (two wire) height of ondary of high inductance value, which alïout 65 feet and a length permits tuning without using much capac- of 180 feet. All the parts ity, across the secondary, in that circuit; of the aerial are extreme- practically no capacity is used and this ly well insulated and very method has been found to permit of much strongly installed to pre- longer distance in working, especially with y ent damage by wind and audions. Also the loading coils used load sleet. Standard phosphor both primary and secondary, and particu- bronze wire and com- larly endeavor to balance up the secondary mercial insulators are circuit with the use of very little capacity. used This method is one of the secrets of the ' It may be stated that remarkable sensitiveness of this set. the transmitting set con- it is of interest to note that No. 24 wire sists of a 1 -kw. transmit- is used for both primary and secondary Fig. t. Illustrating the Vast Depth of Earth Between Two ter, with a condenser ra- of the loose coupler. A two -step amplifier Transatlantic Radio Stations. pacity of Ifief mfd. (three of the Audion type is used in connection when they are in communication with each standard Navy jars in parallel). The rotary with an Audion detector. This amplifier other as, for instance. is the case between gap employed has 12 moving points and embodies sonic original ideas in its details Sayville, L. I., U. S. A., and Nauen, Ger- two stationary electrodes and turns at 8,000 of construction. many, located near Berlin. The approxi- R.P.M. This allows the use of the above it is pointed out that there is an original mate distance between these two modern small condensers and ON es the short wave arrangement of knob switches in the am- high powered wireless stations is 4,000 necessary for 200 -meter work in the pri- plifier circuit that allows (for the first miles and, as Fig. 1 shows, the curvature mary circuit, which to- of earth lying between these two stations gether with close tuning has a chord height of 318 miles. At either through an efficient oscil- station the lofty steel towers supporting lation transformer, with the aerial wires, from which the waves are fair looseness 115 coupling, liberated or sent out, only have a height Of alloy's ,heavy radiation on from 600 to 800 feet in any case. This. a single peaked wave. of course, is a very, very small percentage It is held that repeated of the depth of the earth's curvature inter- tests show a transmitting vening between the two stations, as will be range of between 350 and perceived. 1110 miles under any sort Several theories have been brought forth of normal conditions. Un- from time to time in the progress of the radio art as to the probable method by all other solid bodies with which such long distance wireless tele- which we come in contact graphic signals are propagated around one - daily. fifth and even one- quarter or more of the According to the latest earth's circumference. Many scientists scientific theories of all claim that the waves glide over the surface bodies, even including cast of the earth, as shown in Fig. 2 at A A A, iron, steel, etc., these This is based on the consideration that really consist in great part the earth's surface acts as a charged con- of etheric electrons; the ductor and thus serves to guide the wanes, relative percentage of so to speak, in their path between sta- solid particles in same be- the Excellent Radio Relay Station of the American Radio League. at tions. Of course, the waves radiate, prac, ing extremely small. This New Rochelle. N. Y. tically speaking, equally in all directions theory was at one time from a given point (as about an aerial) strongly advocated by the famous English time in actual practise) a change from the in the form of a circle. Only the half scientist and investigator, Sir Oliver Lodge. receiving on the detector alone to any step loops are supposed to glide over the sur- After much research and experimental of the amplification instantly, without re- face of the earth, as Fig. 2 indicates; the work, which has progressed sufficiently to moving and replacing telephones or dis- give some basis upon which to stand, some turbing any adjustments. This method of of the leading scientists of the day, includ- producing instantaneous amplification and ing Dr. J. A. Fleming the reverse is of great convenience and im- upper strata ofalmosPhee and others, now hold ized to the reflected wat'' theory to account for portance. The whole station was designed long distance radio telegraphy. with the idea of service on long- distance A ß! This is supposed to take place as follows radio "relay" work, and is remarkably effi- As we know, the atmosphere of the earth, cient in operation. A comparison of effects roughly speaking, extends upward to a may be had by noting that Key West sta- '-'`ODD. lepth of 40 or 50 miles. At these high tion, NAR, can be heard and copied easily . á 'Ocean altitudes the atmosphere becomes very is feet from the ordinary telephones, while highly rarefied and it is suspected that a Arlington, NAA. has been copied over cry strong ionization of the electrons in 100 feet distant from a loud -speaking tele- Sayville. L. 1. Nauea, these upper strata of the atmosphere takes phone when this was hooked up in the cir- U S. A. Germany. place. This electrification of the upper cuit. Regular work has been done with Fig. z. Diagram Showing How Wireless Wave strata is caused by the electromagnetic ef- stations using 1 -inch coils at a distance of Are Propagated Over the Earth's fect of the sun's rays. according to these nearly 50 iniles. Surface. theories. It is believed that. considering such long AT - complement half waves of those shown be- distance radio transmission as 4,000 miles, TO INSTALL WIRELESS CHICK ing, of course, in the earth proper. the etheric wavés, as propagatcd from ASHA, OKLA., HIGH SCHOOL. It was formerly believed in the early a station like Sayville. L. L. strikes upward. The Chickasha (Okla.) High School will days of wireless telegraphy that the wire- flue to the earth's curvature. The waves install a wireless telegraph dispatching and less signals were propagated between sta- are then reflected from the highly ionized receiving station for use in the school work. tions (which were located sufficiently far upper strata of the atmosphere; also it is The station will have sufficient power to re- apart so that the mast of one could not be thought further that the reflected wave. ceive messages, from the Arlington wireless seen at the second station) by means of such as at W, is the one that is intercented on the Easternastern coast and from ships what was termed the "bound" ether, locked at the distant receiving station, say at 300 miles out in the Gulf of Mexico. The up or permeating the earth itself and also Nauen, Germany, station is now ready for business.

www.americanradiohistory.com November. 1915 THE ELECTRICAL EXPERIMENTER How to Build a Wave Meter By Samuel Cohen MANY radio experimenters have an dimensions, as shown in Fig. 2. The rotary turns close together. The second or larger idea that the construction and plate shaft (3 -16 -inch diamoter stock) is coil consists of 73 turns of the saine size manipulation of a wave meter is a shown in Fig. 3 and stationary plate rods, magnet wire, wound on evenly, with the difficult matter and therefore they do not of which there arc three. are made in the turns close together. The coils may receive usually build one. However, the construe- same manner, as is shown in Fig. I. Two a few coats of black shellac to help hold the windings firmly in place. It is also a good idea to bind the coils with white linen tape or with cord. si, as to protect the wire from injury. Both coils are provided with two brass or copper attachment straps L. The drawing at Fig. 8 indicates how these plugs arc attached to the card board tubes by simply lending one end of them over as indicated, and a No. 6 -32 machine screw is passed through a hole in the other side of the cardboard ring into a tapped hole in the bras strip. 'These strips should be about II inches apart, and the two terminals of the coil in either case soldered to them. ' one terminal to each plug. The slots in the ends of the strips are fitted, of course, to the binding post of the wave meter at A', B`. These inductances correspond to those i made by the writer and which are designed from standards as made up and tested nn a Siemens & Halske inductance bridge at the radio laboratory of the College of the City of New York. The small or 12 -turn coil has 36,000 cros. inductance, while the 72-turn coil has 1!0:,000 cros. inductance. Fig. !) depicts three curves plotted for different wave lengths, corresponding to different condenser readings. Curve 1 was plotted with the small inductance coil, while curves 2 and 3 represent the use of the large inductance coil. It is very easy then to determine the resonance points of the wave meter by reading the scale setting Details of Wave Meter Condenser and Inductances. of the condenser and referring to the tion and operation of a wave meter is so sets of washers are constructed. naively, curves herewith reproduced. Care should simple that the novice operator may use it. the rotary plate washers, as shown in Fig. be taken not to use the wrung curve, as First and foremost, a wave meter is an .5, and the stationary plate washers, as Fig. they have entirely different values. instrument comprising an inductance and ti illustrates. When all a variable capacity and an indicating de- these parts have been e4 w h ea' c_/o ce ovo mJ vice, such as a telephone receiver or made accurately assemble zoo 1 vacuum tube. the condenser, Fig. 1. The ,love /6'. h AIM iiiducionce ° ri oi oo. cm This article deals with the construction rotary plates are regulated 1 Sc-, na saa ikto INNE:7=EZ7NN Of a wave meter, which was recently built by means of an 8-32 set ::. : =..I 1 and calibrated by the writer. The builder screw. The knob, Fig. 7, ::i:' ... _....I::::.:.._...... _._.a._:.8.:,:::: __..__...I __nü of this instrument does not necessarily need is made of any insulating _.u_ i.nu_e to calibrate his wave meter, but he should material, preferably hard i:°:li::ni:::'.i::::::i ::::ï :ái:iii:::¡=:ñ construct it according to dimensions given. rubber. °"...... : :: I.:: ..: :°. :i.:::i :: This variable condenser .n:.::.: _ . _...._... .r:. : .... has its 180° scale marked iiiirralg..._.n_.... _ ..w.':: n.::4.1: :Ìri" t°:' :11C:CC off in :t0 equal divisions. ':: :.: IW...... :...::.7 __:..!.-:_..: ..._ Its maximum capacity .r.::_::::: _.a:m_::r°...: %I::i:.i.um the rotary plates with :::ís;.:r" _ ' totally intermeshed with _n.,.. ._ 'L :.I:_. :::°:::iEtl....: _ the fixed plates is .000795 ":11.. aa microfarads. At 15 scale :..i.nffiuu.ou.n.u.n.._...... _.I._..._ u000 :S:aEMI :ln:il'a..::..J divisions the capacity ...... _. would be half this value in microfarads. The wave tare #i/h,r.dur/ance+rZakcaocml Cow //i/eOfi1h corhr length can be calculated á from the usual formula: IWO mop 1111=s= W.L. in meters =59,6 X ../ L. cros. X C. m.f. :C3H::I:::i:7i n.:::1:3PF::.:i:....._I: ii!í'I'i:l:::: We now come to the in- ® i. . n. ductance coils, of which :._: ui=._: D .:.°::M:íii:g _ Fig. 8. Inductance Coil Make -Up. there are two. These are _n._:Y:-:R:::_::.. shown in detail as to their ° ....._...... The writer advises the consultation of a make -up at Fig. 8. and E_:::iiÇl1:=::.:.:I;ç. good text -book treating on the manipula- some substantial cardboard tion and construction of these meters be- tubing or wooden rings . _ fore building such an instrument. are to be used, which bave "F .:3.. _ .,_:.i_'_ ::_. :e°:::Ó:W:ÿ-i' The first thing to build is the condenser. an exact outside diameter o :...:iC:.a:.l:::::1:.C'..i 11:a.:.N._ which is of the rotary air dielectric type. of 51/4 inches. Two such _aaa:;:.:a:tlNY.aa.a:Y.na..11 is necessary "forms" or are Very little explanation for the rings 9. pate Length Inductance and Capacity Cures for Use description of this condenser, as all the de- necessary and the smaller With \'ave Meter. tails are plain and self -explanatory. Fifteen inductance coil consists rotary and 16 fixed plates of No. 20 B. & S. of 12 turns of No. 20 B. & S. enameled mag- The curve No. 3 was plotted for those gauge aluminum arc made according to net wire, wound on very evenly, with the desiring to measure waves up to 3,5()0 mc-

www.americanradiohistory.com 342 THE ELECTRICAL EXPERIMENTER November, 19'5 ters in length or more. To use this curve terial, preferably hard rubber, and turned ELECTRIC VARNISH. and its equivalent wave lengths as given, out in a lathe. The dimensions are given. Powder some common sealing wax in a the variable condenser of the wave meter Next mark out a circle having a radius of mortar, place the fragments in a bottle and must be placed in a glass or other jar, so 1% inches and on it lay out evenly 20 points, cover with alcohol. Keep in a warm place that the moving and fixed plates will be and then sct in them 20 brass nails having until all the sealing wax is dissolved. This immersed in castor oil. This raises the A -inch shank. After having done this ob- varnish may be used to cover magnets and capacity of the condenser about five times, tain a 1 -inch brass or copper washer C and other parts of electrical apparatus. the as and hence gives us greater wave length mount it carefully on circle, shown. Electric Cement. It is fastened in place by Melt means of three brass screws. equal parts of beeswax and rosin in one their This ring is used to connect together and stir -fourth of weight of red ochre, stirring until well one of the end connections of mixed. This cement is used for fastening the winding by a brush, as the metal portions instruments shown in Fig. 1. of electrical to their insulating supports, etc. A 1/4 -inch hole is next drilled in the center the Contributed by of V. BOLLERER. reel A, and into it force a ALEXANDER brass tube % inch long having an internal diameter of á# THAT LIGHTNING SWITCH. inch. Into this brass tube the Every good amateur wireless station has shaft D is placed, which is a lightning to ground the aerial with. made brass and switch from stock, The switch is used because it dissipates details are shown in Fig. 2. static aerial currents before they have had The contact maker is now time to accumulate into a heavy charge, made as in 3, drawing which and thus prevents damage to. the building rigs. to and ii. Diagrams for Using Wave Meter on Trans - is mitting and Receiving Circuits. then soldered to the shaft as and apparatus. seen. The wire from the switch to earth should same inductance coil. i. e., Now, being finished with all the neces- ranges with the be a No. 4 B. & S. (about i/a inch diam- sary details, the is next be 72 -turn coil, with 1,036,000 cms. winding to con- eter) copper conductor, connected on the Figs. 10 and 11 indicate sidered. There are 20 sections to be wound The diagrams at outside of the building and taking a straight how the wave meter is hooked up. At Fig. on the coil. The first winding consists of course to the ground proper. 10, the sending 10 turns of No. 36 D. C. magnet used, say for measuring C. wire. This "ground" should consist of a 12- wave length, the inductance coil I of the foot by 1 -inch diameter iron pipe driven is to the send- meter held just close enough into moist earth, or a 10 -inch square piece so that a is heard ing helix readable sound of copper buried 6 feet deep. Some T. The variable in the telephone receivers amateurs arse a connection made to a well - the condenser is regulated or turned until pump (iron pipe), but in any case the con- is the loudest signals are heard. This nection must be soldered and taped. meter cir- point of resonance in the wave A 100 -ampere, 250 or 600 -volt S. P. D. T. the wave length cuit, and corresponding switch is specified, with the aerial connected value for this setting of the condenser is to the blade, the ground to one jaw and read off from the curve 9. If the condenser the apparatus to the other jaw. This reading was, say 20 degrees with the large switch may be obtained from any electrical inductance coil in use, then by noting the supply company, but in order to stand the wave length vertical line intersecting the sending voltage the base should preferably curve 2 ( for large inductance) and the be made of marble or porcelain. The (air) condenser horizontal line, it is seen cheapest way to do this is to buy a slate - that the wave length is 1,420 meters. base switch and remount on marble your- In a similar way the wave length is self. measured at a receiving station (see Fig. If the aerial proper is composed of four 11). The wave meter inductance coil is No. 14 copper wires, then the lead -in should placed in sufficiently close proximity to the consist of four No. 14 copper wires or a loose coupler coils until the incoming sig- No. 6 B. & S. solid wire, stranded cable nals can be heard in the meter 'phones. being best, of course. The variable condenser is then turned until In order to protect the switch from be- the signals are heard loudest and this con- ing broken, it should be fastened with denser setting in degrees, referred to the screws in a box with a hinged cover, and curves in Fig. 9 as explained above, gives the lead -in fastened by an insulator before the equivalent wave length in meters. it reaches the switch. Another common method in vogue for measuring received signal wave lengths is as follows: When a certain station is tuned in sharpest on the regular receiving Loading Coil Mounted on Tuner Slider. set the instruments are left alone as they The one end of this coil is brought to the set. Then the wave meter is brought near brass washer C and firmly soldered, while the coupler, etc., and by exciting the wave the other end is soldered to the shank of meter circuit (by connecting a buzzer vi- the first brass tack. The second winding brator across it) it is possible to hear the consists of 15 turns of the same wire, and meter oscillations by induction in the the connections are made with the first 'phones of the regular receiving set. When tack, while the other joins on to the second the meter signals are heard loudest, then it tack. All the other windings are made in is set to the wave length corresponding to the same way, and each winding is in- the setting of the receiving apparatus. creased by five turns. From the data here given it is possible The shaft is then screwed on the slider to easily build a wave meter with any and carefully adjusted to see that the coil rotary condenser, using the standard in- votates easily and that the switch blade ductances here cited. makes contact with each point. Now connect the aerial wire to the brush LOADING COIL MOUNTED ON binding post, while the coil end wire joins SLIDER. the regular receiving circuit. By turning A miniature loading coil which is placed the reel the wave length is regulated, and on top of the loose coupler slider can also the slider can be moved back and readily be made, and at the same time have forth. This method of tuning is very effi- a fairly large wave length. This instru- cient and at the same time saves some ment has been tested out in several com- space, besides enabling two operations to Practical Method of Installing Lightning Switch. mercial radio stations very successfully. be accomplished by the hand in one posi- By referring to the drawings herewith tion. Rain can be prevented from running' given the construction will be quite evi- [This device has been developed by the down the lead -in by making a half loop dent. First comes a circular form A, Fig. Eugene T. Turney Co., which has patents in it. Contributed by 1, which is made of some insulating ma- pending on it.] WM. R. COTTRELL.

www.americanradiohistory.com November, (915 THE ELECTRICAL EXPERIMENTER 343 I

AN EFFICIENT DETECTOR A HOME -MADE TUNING COIL. A HANDY DETECTOR SWITCH. I give herewith sketch and description The amateur is often hampered by the I have found the following switch very of a simple yet efficient detector, made lack of funds and therefore the tuning coil desirable for throwing one of a number from a double-pole single -throw switch, herewith described will be found beneficial of detectors into circuit. which I am sure will be found useful to in overcoming this embarrassment. This can he easily made by placing some the amateur. First a cylinder 4 inches in diameter is exploded cartridge shells on a wooden made from cardboard and coated with par - base, as shown in sketch, and connecting affine to insure perfect insulation, or, better these to the two pieces of brass by means still, a wooden cylinder may be used. This of the brass strips, indicated in sketch cylinder should be 11 inches long and wound with a layer of 20 to 22 copper II IIIIIIIIIIIIIIIIII I H111101111 wires with cotton covering. (Enamel wire will also be found effectual). A rod is now heated red hot and drawn along the coil, thus burning off the cotton insulation in two straight lines, each about i/a inch wide; these bare strips forming paths where the sliders make contact. For enamel insulation sand paper serves to remove the 111111111 coating along the slider paths. I I A convenient size frame of 1/4-inch stock is then constructed, across the ends of which are placed two brass slider rods, with a slider on each. These sliders are made from pieces of brass or copper with holes to fit the rod, contact being produced by fast- fi ening (soldering) a strip of spring brass or copper onto the under side; while at the top a piece of hard rubber should be firmly fixed to prevent the coil from being grounded through the body. (Sliders can Unique Detector Switch. Detector Made From Knife Switch very cheaply be purchased from any supply attached. The sliding brass strips are Procure a double -pole, single -t Crow house). The binding posts can be pro- and from old dry cells, and in the draw- riveted onto a piece of sheet fiber, through knife switch; unscrew the hinge post cured is a hole. A rod is ing herewith is shown the make which bored passed place a washer between the base and post, -up, through and connected to the wood base. so as to allow the switch blade to be there being four terminals. By properly the following the above directions, good It is then bent, and if desired a handle swung from side to side to facilitate results may be adjustment. Before replacing the switch may be realized with this coil. attached. by The figures from 1 to 5 represent the blade, solder on it a fine wire coil of Contributed bullet shells and numbers of detectors; and either phosphor- bronze or brass, to make SAMUEL F. DUNN. take jaw the letters A, B are the connections for contact with the crystal. Now the phones and instruments. post and bend it into shape to hold the crystal, as shown in Fig. 2. Contributed by GORDON SCHAUB. This completes the detector; the other circuit the de- switch being used to short- .a:u also be con- I id ia A SIMPLE TUNER SLIDER. tector while sending or it may quuoul n ullunilmliln'nnullu If the constructor to verted into a detector. I II,; j lil1 The following articles are required has means of short -circuiting the detector II make this handy little slider: on the antenna switch, and does not need A. piece of hard wood 7 in. x % in. x the added detector, he may use a single pole, 3 in., in which a groove 14 in. x 14 in. single throw switch, and will not have to is cut to allow slider to pass through. A change blades, as in the case of the sheet of tin or copper % in. x % in. is double -pole, single throw switch, where fitted over this groove, and screwed or the double blade will have to be substi- nailed on, as the constructor sees fit. Ou tuted by the single blades. Connections this is soldered the slider contact, which a '1k in. pro- are shown. Coil. has been properly shaped and Contributed by WILLIAM GUIER. A Home =Made Tuning jection allowed, in order to make contact with rod. A HANDY AERIAL SWITCH. SMOKE STACK SUPPORTS WIRE- This slider works very easily when the The following instructions will be found LESS AERIALS. slider contact is made of a thin but flex- very serviceable for constructing an effi- The big smoke stack at the Brush Elec- Tex., ible piece of brass or phosphor bronze. cient and simple aerial switch at a very tric Co.'s power plant at Galveston, is now a coat its designer The hard wood handle given nominal cost. This switch may be thrown was probably never intended by of shellac and the slider is ready for use. tobe used as a mast to hold wireless aerials, but it has proved a wonderfully good thing Contributed by for the purpose, and messages are now be- CARL LINXWEILER. ing transmitted from the top of the smoke stack to points as far away as Vera Cruz Except for the wireless on the army transport Buford, which was in continuous operation all through the recent storm, the Marconi wireless plant at the Brush power house was the only wireless in the city connecting Galveston with the outside world. The Marconi aerials went down during the height of the storm and Manager Camp- bell immediately got busy looking for another place from which to operate. Tuning Coil Slider Made from Wood. of the other. Then tighten to whatever pressure desired. Set the switches at right THE CHAMPAIGN, ILL., WIRELESS angles and fasten to either a wall or table. If desired, a special base may be made CLUB. Aerial Switch Composed of z D. P. S. T. Knife for this purpose, as sketch indicates. The Champaign Wireless Club, of Cham- Switches. This should be composed of a block of paign, Ill., was organized Aug. 4, 1915. It from transmitting to receiving, and vice - wood, t/ x31x6 inches long, screwed at has nine members: Maurice Lee, presi- versa, very quickly and satisfactorily. right angles to another block, 1/(2x3%x61/4 dent; Walter Thornhill, vice -president; Obtain two double pole, single throw inches long, the corners of which may be Joseph Tipiword, secretary; Ernest Mills, switches and from one remove the arm beveled to produce a neater effect. Con- treasurer, and T. McHown, S. Hall, S. and place the lugs over the arm and lugs tributed by D. K. WALKER. Bostic, O. Bucker and N. Chatman.

www.americanradiohistory.com THE ELECTRICAL EXPERIMENTER November, 1915

This department will award the following monthly prizes: FIRST PRIZE, 52.00: SECOND PRIZE, 52.06; THIRD PRIZE. S1.00. The idea of this department is to accomplish new things with old apparatus or old material, and for the most useful, practical and original idea submitted to the Editors of this department, a monthly series of prizes will be awarded. For the best ideas submitted a prize of 58.00 will be given; for the second best idea a $2.00 prize, and for the third best a prize of $1.00. The article need not be very elaborate, and rough sketches are sufficient. We will make the mechanical drawings.

FIRST PRIZE $3.00. SECOND PRIZE $2.00. THiRD PRIZE $1.00. AN ELECTRIC SOLDERING IRON. AN AUTOMATIC TRANSMITTING FUSES FOR BATTERY CIRCUITS. The following is an electric soldering KEY. A small fuse for battery circuits may be iron ihat I have found very useful and I give below a description of an auto- made of a small piece of tin -foil. The tin- particularly accessible for niches, corners matic key. which, although it may appear foil is cut in the form of a narrow strip or tight places, as well as for use in ordi- complicated, is really very simple. and connected between two binding post -. - nary soldering. The ìrst consideration is the base. This Its size will vary according to the current At A is a small carbon pencil, forced is made of oak 4x7x r inches. with ten it has to carry. Contributed by into the end of a copper tube B. C is a 41. -inch holes, drilled and countersunk, as W. R. COTTRELL. small wooden file handle, drilled out, so shown in Fig. 1. The lever A, Fig. 1. that the copper tube can slide in snugly. is composed of a 3/4-inch square brass rod. 2. drilled and tapped, as shown in Fig. IIIIIIII'IIIIIIIIIIIIIIIINI The contacts X and P (Fig. 1) are for Tin oil trip dashes. A small silver piece about á inch a in diameter is soldered to the center of the lever, l'a inch from the end at " \" The ether contact is soldered to the screw in the post P'. Two inches from the end a s. -inch ka

Foil

Mains M ca il r tri 11111 11111111111111111111111111111111111111111111111111111111 iI1111III11111111111I11I1IIlI1k

Arc T>pe Electric Soldering Iron. At D is seen a single covered conductor soldered on the copper tube B. A smaa variable resistance coil to regulate the Battery Fuses Made from Tin -Foil and Mica. current is depicted at E. while F shows a switch for breaking the circuit. G is the piece that the article II is to he sol- Fig. t. Assembled Automatic Telegraph Key phor bronze about No. 32 or 34 B. & S., and measures 3t/axt/-I' inches. This makes dered to and I represents the soldering hole is bored, and into this is forced a stee flux; or if desired, solder may be used contact with a -inch diameter round piece pin, as Fig. 3 depicts. This pin forms the of silver, soldered into a brass cup and with acid, provided a small piece is cut pivot which carries the lever. The bear off to be sol- bolted on to the spring through a a, -inch and placed on the article ings are shown in Fig. 4, while R, Fig. 1 dered. At J is shown the "arc" formed diameter hole. The weight \V is made of is a piece of 'Is -inch hard rubber or fiber brass. ?Éx?ix ?s inch. A slot is sawed in by closing the circuit and holding directly sheet. finished as illustrated in Fig. 8. Thi over the article to be soltlered. K is an- the center of the bottom .t inch deep. A other insulated wire to be grounded to set-screw is then placed in one side. The spring H is a U- shaped piece of phosphor the article being soldered. Contact % This iron may be made either large or Ha/e bronze 1 inch long and inch wide. On _r one side of the "U," the silver contact is small, as the .,udder sees fit. I have had 'ID1 soldered and a ais -inch hole is drilled in the fair success with it and feel sure that I Taxed r8 32J 1, 1 other amateurs will also find it efficient. i r other side. The spring is fastened by Contributed by ;,t e: -C means of an 8 -32 screw to the post G. FlG 2 four posts F, F', G, G', Fig. 1, are IL \ROLD SPAULDING. FIG6 The 1r each 1 inch long by 1/i inch square. as : AI' shown in Fig. 7. A 1I -inch hole is drilled TO BORE HOLES IN GLASS. 4 The following method of making per- FIG 3'4%) Tapped 8-31 inch deep in the bottom of each and Four 8 -32 forations through glass may be of interest: 'Holes tapped for an 8 -32 screw. Take an old triangular file and break off screws, with knurled heads and lock nuts its tip about 1_ in. from the end. Place FIG 7 about 1 inch long, are required for these the shank end of the file in a brace and 832Tap Hole posts. The posts P and P', Fig. 1, are use it as a drill. The glass should be -1 h. xi"xiHate similar to the others, except that a hole drilled slowly, using kerosene as a lubri- FI64, is inch in diameter is drilled through the cant. At first it may be found rather dif- ri" post at the top. The screws to which the ficult, but after once starting the shape of oza1 springs are fastened slide in these holes. the file causes it to act as a reamer. The two screws are without heads, but are Contributed by W. R. COTTRELL. FIG 8 fitted with knurled lock nuts. FI6 5 The springs S and S', Fig. 1, are made of No. 28 phosphor bronze wire. They FURNITURE POLISH. Details of Parts for Making Automatic Tele- 1/-, Herewith is submitted a formula far graph Key. are 1/is inch in diameter and inch long. making a cheap furniture polish, which will One end of each spring is attached to one be found very efficacious: One -half gallon is fastened to the lever by an 8 -32 screw of the screws and the other end to the gasoline, ? gallon light lubricating oil, 2 ';q inch long. At K may be seen a hard lever. drops of oil of cedar. rubber key knob. Connections are made between the posts Contributed hy- MONROE MILAN. The spring G, Fig. 1, is made of phos- F' and G and one binding post; also be-

www.americanradiohistory.com November. 1915 THE ELECTRICAL EXPERIMENTER 345

tween the lever bearing and the other ated by dry batteries tor may Le attached to rod must have a knurled thumb nut with binding post. the electric light system in circuit with a which to turn it. A. brass nut should first The speed at which the signals can be "hell- ringing" transformer, if batteries are be put on the rod, to which is soldered the made may be varied by moving the weight used they should be placed on a shelf or wire for connection with the binding post. W along the spring. on the hack of the table attached to the The switch handle is now placed in the Contributed by J. L. GREEN. center of the remaining space; a block of 11IIIIIII sufficient thickness being set under it to "SAFETY FIRST' ON THE MOTOR- bring it on a level with the upper surface IIIII of the carbons, i.e., with the end of the CYCLE. lever resting on them. Any number of here is a simple little attachment, the carbons may be used. but it has been found employment of which will insure riders of that the more employed the more sensitive motor vehicles against accident when turn- will be the regulator. ing sharp corners or when driving through The regulating screw must come in con- dark roads in the country, or otherwise. tact with the carbon near it, or the connec- This device constitutes a "red" rear lamp tion may be made from the carbon itself. and two red arrows, which are brilliantly By sliding the lever over the carbons, dif- illuminated by the touch of a button. The irt ferent resistances may be obtained nicely, construction is as follows: while the screw serves to adjust each step First make a small -sized wooden cabinet with fine precision. about 7x3x3 inches. Take a piece of card- IÌ Contributed by SELMER WICK. board cut to the above dimensions, and aid of it with a sharp knife cut out, with the u a ruler, two arrows, leaving a square space THE MAGNETO ELECTRIC DOOR in the center for the rear light. Then pro- BELL. cure some red tissue paper, or better, some red glass and glue firmly against the frame The disadvantages of the common electric door bell often outweigh its advan- of the arrows and rear lamp on the card- tages. board; cover and allow to dry. Now screw r2 The batteries are continually run- in three miniature lamp receptacles in the ning down, due to excessive use or a short base of the cabinet; fasten the lamps, make circuit. and the button seems to be an ir- Home -Made Electric Egg -Beater resistible temptation to every youngster Red Piece ofCard. Wooden motor by a flexible wire of sufficient length Tail to allow the beater to be used on any part Lamp Soaarrd 7inx3in Cabinet. of the table. A small switch should be placed on the motor or within reach of the left hand. This machine will beat any nmmber of eggs in a very short time and it does not get "tired." Contributed by Tungsten Lamps Red Tissue Paper HAMILTON A. HOOPER. A USEFUL CARBON BATTERY RH. Push. HPush. RHEOSTAT. Anyone desiring a cheap hut extrémely efficient rheostat will find that this one Push Buttons. will exceed their expectations, both for simplicity of construction and for efficiency ilir in the regulation of battery current. Batteries. All that is required to build it is a hard wood baseboard, a number of flashlight or other battery carbons and a switch handle. The carbons are placed in a rectangular Tail Lamp compartment made by screwing small e strips of wood on both sides and ends of the space they occupy. A strip of wood Electric Signal for Tail -End of Bicycles and may be laid across the top to prevent them Motorcycles. necessary connections and tack the card- A Magneto Door Bell Saves Batteries. with board cover on the frame of cabinet who carpet tacks. The wiring is very simple delights in sticking a pin in it to keep and the battery may be clamped on the the bell ringing. Although the bell -ring- main bar. Two push- buttons, as used on ing transformer does away with battery automobiles, are attached to both handle- trouble, it leaves much to be desired. bars and set in connection with the cor- To eliminate all these mishaps I have light. designed an easily constructed magneto responding second Whenever it is desired to turn in a cer- door bell. Purchase a -hand mag- tain direction (either right or left) the neto and a polarized bell. Remove the corresponding button is pushed: the light two brass gears from the magneto and flares up and any approaching vehicles or put a small spool on the shaft of the mag- pedestrians are informed of the intentions neto. and whereabouts of said motor vehicle, The magneto is mounted above the door thereby obviating all danger. Contributed /71// vg/fRo as per sketch and a cord fastened to the by WILLIAM WARTON. regular pull bell is passed around the spool several times, a tack is driven in to kcep it from slipping and the free end of the SIMPLE ELECTRIC EGG BEATER cord is fastened to a strong spring, hooked FITS ANY BOWL. into a screw -eye. and screwed into the top A very simple electric egg heater can be '!//// . a of the door frame. Wires are run from made at home and at small expense, as the magneto to the bell. which is located in shown in the drawing. The egg beater is any convenient place. These wires may be so constructed that it fits bowls of vary- quite small. as the bell will ring through ing sizes, thus adding to its convenience an enormous resistance. and effectiveness A study of the diagram will show that All that is needed is a "toy" electric Old Battery Carbons Form Useful Rheostat. a pull on the handle of the bell will spin motor and three pieces of stiff wire. One the magneto armature and when the handle piece for a handle, one for the blades and from being forced out of place. .\ hole is is released the spring will pull it back. the third for a leg or support as shown in then drilled on one side, into which a ringing the bell in both cases. Contributed the illustration. The motor may he oper- threaded brass rod is tightly fitted. This by THOMAS W. BENSON. www.americanradiohistory.com 346 THE ELECTRICAL EXPERIMENTER NovemIXr, lt 15

ELECTROCUTION TRAP FOR should be cut is inch apart in the strips ful and spectacular effect in the darkened INSECTS. to accommodate the two bare wires. No room. A German inventor has devised a very connection exists between the wires until Contributed by R. E. RYBERG. interesting electrocution trap for insects. the insect "crosses" them. Upon an insulated frame of either pris- Our second illustration shows a similar A "SAFE" BURGLAR ALARM. matic or globular form two naked metallic style electrical insect trap or annihilator, Its mechanism is so simple and accurate and in this case the fiber or other strips that it can be thoroughly relied upon. The supporting the two parallel, oppositely only thing necessary is to chisel out neatly charged electrical conductors, are tapered one of your floor boards near your safe or as shown. At the base of these fiber up- valuables, about 2 inches in length. To rights supporting the two charged wires is make the device, bore a hole in a block of suitably secured a small cup, in which wood big enough so as to admit rod "R" as honey or some other insect delicacy may shown. On the top end fasten a hard rub- be placed. An electric bulb, as usual in this class of apparatus, is placed inside the wire cage as in the previous design described above. A single switch may control both the light and the grid wires, as becomes evident. MECHANICAL WAVES MADE VISIBLE ELECTRICALLY. The following is a description of a novel and very interesting experiment, which is ,411II very easily performed, showing the sta- w tionary mechanical waves on a heated elec- hllUimuuIIIInIIIIUIIIIYUUIIIIIIIIIIII IIIimVII tric wire. Resistance wire is used to ren- der it luminous, therefore the room should be darkened to obtain the best effects. I Removing Chair From Spring Switch Gives have tried two sizes of "Nichrome" wire; Alarm. No. 19 gauge, of which about 12 feet was ber disc "A." At the bottom end a disc used, and about 6 feet of No. 24. The of spring brass. Fasten two common tacks exact length for 110 volts may be deter- and make necessary connections. Explana- mined by the experimenter; or, better still, tion : Place a chair on the side of your a variable impedance coil may be used, in safe as shown in figure so that one of the which event, the length of wire need not legs rests on the top of "R." You have now set the alarm. As soon as the intruder i comes to the safe he removes the innocent Grdn'res 46 looking chair, which naturally is in his way. and the pressure of the spring in the device consequently pushes up the shaft, where- One Type of Electric Insect Destroyer. upon the brass disc "B" is connected with conductors are coiled in a spiral with about the bell and closes the circuit. But the 'eta inch or less space between the wind- initiated can remove the chair as he pleases, ings. The two conductors are connected provided the switch is off. with a source of electricity in such a man- Contributed by ner that the current cannot circulate until JAMES BERK. it is actually used in killing an insect. This is one of the advantages of the apparatus; TO RENEW DRY CELLS. obviously no electrical energy is wasted. Dry cells, if not too far spent, can be Insects are attracted either with sugar renewed by drilling (not punching) a hole water or any other sweet substance. (A) between the binding posts (B -B) At night time electric lights can be used. and pouring chemically pure ammonia into The glare of shining metallic parts will Making Mechanical Waves on Wire Visible. it. The hole is then sealed up with wax also serve as an additional attraction. As be and as efficient service as when it was so exact. At any rate, the wire must new can be obtained from the renovated soon as the insects touch the bait or the be between a dull red and a white heat. light, and come in contact with any two To produce the motion of the wire a of the naked wires, they are electrocuted buzzer is used to set up mechanical waves. at once and drop down to the bottom of Not having a buzzer on hand I used a bell the trap. The current passes only for an with the clapper rod cut off as short as instant and is very feeble. possible and the end bent to form a hook. The resistance wire is fastened to the hook, where one side of the 110 -volt circuit is connected. The wire is stretched out to the desired length, where the other side of the circuit is connected; the impedance coil being in series with it, as diagram shows. The switch for the buzzer circuit should now be closed and the room darkened. By i means of the adjustable impedance coil regulator switch the wire should be raised to the desired temperature and tightened up again, as it expands when heated. By varying the tension of the wire the waves may be observed. When the correct tension is obtained it should be kept constant. The loops or anti- nodes, and nodes of motion. can be easily seen. The loop is of motion, which is easily Another Form of Electric Insect 'I'rap. the maximum observed, as it cools quicker and will be The sketch herewith depicts how, with at a "red heat" when the node is "white." a few pieces of horn fiber rod carrying the During the course of one experiment the net of twin wires, with a lamp inside it, In my it I wire broke. haste to repair Method of Revitalizing Dry Cells. one of these useful devices can be made. made a loose joint. The resistance of the A tin pan can be fastened to the bottom joint being high, it became luminous, while battery. The ammonia will cost little if of the fiber strips in which to catch the the rest of the wire remained invisible. bought.in jars at a time and preserved for dead insects. The top support can be of The fantastic shapes and figures emanating future: ,use. wax -impregnated wood or of fiber. Slots from the juncture produced a very beauti- Contributed by A. BEL JEA. www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 347 A GOOD SILVER -PLATING CONVERSION OF SOLUTION. RECIPE FORMULAS. This solution will be found of excellent Sometimes amateurs see a formula or use in silver -plating different parts of elec- recipe which they might want to use, but trical apparatus, jewelry, etc. Copper, cannot do so 'because the ingredients are Brass and German silver articles only call expressed in "parts." A part in the sense be plated. of the word might mean anything. If Cut a silver quarter into small pieces specified in solids, it might mean anywhere and place in a porcelain or glass dish. from a grain to a ton; or if in liquids, Place the dish, uncovered, in a pail of might mean anywhere from a drop to a warm water and add i/ ounce of nitric barrel; but if one should keep to the unit acid to the metal. Let dish stand in the and use multiples it would be impossible water until metal is all dissolved. Now to make a mistake. add 14 gill of water and one teaspoonful For example, if the formula should of fine salt. Let the precipitate settle and say: Use 1 part of nitric acid, 2 parts of EDITED BY'S.GERNSBAGK filter. Add more salt to the filtrate, and potassium bichromate (saturated solution), any more falls filter again. Under this heading we will publish every month if precipitate 5 parts of water (apologies to S. G. in useful information to Mechanics, Electricity and Wash the precipitate on the filter paper Electrical Experimenter, April, 1915, under course, to have Chemistry. We shall be pleased, of until the water shows no acid when tested "Wrinkles, Recipes and Formulas," No. 3) ; our readers send us any recipes, formulas, wrinkles, new ideas, etc. useful to the experimenter, which with filter paper. Add one pint of water all that is necessary would be to designate will be duly paid for, upon publication, if acceptable. to the precipitate and four scruples of the exact quantity that the part represents; potassium cyanide. Great care must be then, if one grain for solids and one minim used in handling the cyanide, or the solu- for liquids should be used, the above FORMULA 15. tion after it is added, as it is a deadly formula would work out as follows: Blackings for Boots and Shoes. and almost instantaneous poison. Put a 'Nitric acid, 1 minim; potassium bichromate, 1. French Paste for Patent Leather.- piece of zinc about 2x1x33fi inches in the 2 grains, and water. 5 minims. Of course, Take G drm. of Pure Wax, 2 oz. of Olive solution and it is ready for use. this can be multiplied to any proportion. Oil. The wax has to be melted in a water No electric battery is needed. Simply For further reference the following table bath. Mix thoroughly by stirring; heat clean the articles to be plated in a hot will also he found very useful: moderately. Add 1/ oz. of Oil of Turpen- potash solution and rinse good in boiling 'Grams., tine and /3 oz. of Oil of Lavender. The water. Immerse in the solution for about No. of or parts. Grains. Minims. c.c. be 1/. to on mixture will form a paste, which should minute, allowing the article rest 1 1 1 1 put in boxes before it becomes cool. Apply the zinc. \Vipe dry with a cloth and re- 2 2 2 2 with a linen rag. A very good paste, peat. Heavier coatings can be given by 3 3 3 3 4 4 4 4 which keeps the leather soft and restores repeating. Articles will take a high polish 5 5 5 5 the gloss. and wear fine. 10 10 10 10 20 1 'Cr._ 2. Tan Shoes. 1 oz. by E. E. ZANDER. 20 20 Dressing for -Take Contributed 50 50 50 50 1 of Annatto, 1 oz. of Gamboge, oz. of 60 1 dr, l dr. GO Acacia, 2 oz. of Catechu, 2 oz. of Hydro- A HANDY SPIRIT LAMP. 100 1 dr. 2 scr. 1 dr. 40 min. 100 Add water enough to make All that is needed to make this useful 250 % oz. 32 grs. 1 dr. 40 min. 250 chloric Acid. 500 1 oz. 62 grs. % oz. 10 min. 500 40 ounces. 1.000 2!!I oz. 16 grs. 2 oz. 40 min. 1,000 3. Polish for Tan and Russet Shoes. - 2,500 1 / oz. 94 grs. r oz. 1 dr. 40 min. 2,500 5.000 11!1 oz. 79 grs. 10 oz. 3 dr. 20 min. 5,000 1,oz. of Dark Yellow Wax, 3 oz. of Oil of 10,000 l 1b. 6Yi oz. 49 grs. 20 oz. 0 dr. 40 min. 10,000 Turpentine, 1 oz. of Palm Oil, 15 min. of and oil 'il1etric system: Figures for grammes and cubic Oil of Mirban. Melt the wax centimeters together, add the turpentine, and, when are the same. nearly cool, the oil of Mirban. It would be advisable for experimenters 4. French Boot Blacking.-Dissolve 150 to copy the above table and put it in a con- parts of Wax and 15 parts of Tallow in a venient place in the laboratory, as it will mixture of 200 parts of Linseed Oil, 20 be found very helpful for the rapid calcu- parts of Litharge, 100 parts of Molasses at lation of parts into liquids or solids, as the a temperature of 2.10° F. After this add case might be. Contributed by 103 parts of Lampblack. When cool dilute A. \VILSDON. the mixture with 280 parts of Spirits of Turpentine, and finally mix with a solution of 5 parts of Gum Lac and 2 parts of Ani- CANNED HEAT. line Violet in 35 parts of Alcohol. Canned heat, a new discovery, is noth- 5. Germait Boot Blacking.-Melt to- ing else but solidified alcohol. The alcohol gether 90 parts of Ccresine (or Beeswax), is suspended in a soap mixture so that it 30 parts of Oil of Spermaceti, 350 parts of may he used for heating purposes and still Spirits of Turpentine. with 20 parts of not be open to the dangers from alcohol Asphalt Varnish. Add 10 parts of Borax, when burned alone. 20 parts of Lampblack, 10 parts of Prus- Useful Alcohol Torch. Solidified alcohol may be made accord- sion Blue, 5 parts of Nitro -Benzol. ing to the following formula: Stearic 6. Self -Shining Blacking. -Dissolve 8 oz. little spirit lamp are: An old ink or muci- acid, 81.. grammes; caustic soda. 1 -35 /100 of Gum Arabic in 8 oz. of best Black Ink; lage bottle, a woollen cork, a small tube, a grammes; alcohol (grain or denatured). add 2 oz. of Olive Oil. Mix thoroughly piece of asbestos and an old lamp wick. sufficient quantity to make 100 grammes. and then add 4 oz. of Strong Vinegar, 3 The cork should be made of hard wood Dissolve the stearic acid in about 50 oz. of Brown Sugar, 2 oz. of Alcohol. and as seen in the diagram should have a grammes of alcohol by the aid of heat. 7. Waterproof Blacking. -Melt together hole bored through its center. Through Dissolve the caustic soda in about 40 3 oz. of Beeswax and 3 oz. of Black Resin; this a piece of metal tubing about 1ti grammes of alcohol. Mix and warm until inches then stir in 1 pt. of Boiled Oil. When it long is inserted. There should be a the two solutions combine. Pour into suit- has cooled a little add 3 oz. of Oil of Tur- notch cut in the side of the cork to admit able moulds. The moulds ordinarily used pentine. air. are friction -top tin cans capable of hold- 8. Russian Waterproof Boot Blacking. A piece of asbestos should be procured ing three or four fluid ounces. To ignite, - is Melt 1 oz. of Becswo.r. lk oz. of Suet, 2 oz. (a piece of an old asbestos shingle will do) the cover removed and a lighted match of Olive Oil. Add 'k oz. of Lampblack about one inch in diameter with a hole held over the solid mixture. To extin- and stir till cool. \Varm the boots and bored through the center to admit the tt.he. guish, the cover is slipped on the can. apply the blacking. The wick, which may be flat, should be run Care should be taken not to tip over a 9. Liquid Shoe Blacking.--5 oz. of .4ni- up through the tube to the desired height. lighted can, as when the mixture is burn- alcohol as ing it becomes a nial Charcoal, 4 oz. of Molasses, 3/4 oz. \Vond should be used as fuel semi -liquid and, there- Sweet Oil. Triturate until the oil is thor- it gives intense heat and little smoke. fore. a source of danger if spilled. When oughly incorporated, then stir in 1/4 pint of Contributed by HARRY RiDINGER. the fire is extinguished and the mass allowed cool the contents again Vinegar and 1/4 pint of Beer Lees. to of the can 10. Finishing Blacking.-Mix together t/ neat the whole over a slow fire and stir solidifies. The soap itself does not burn but is can oz. of Gelatine, tk oz. of Indigo, 1 oz. of till thoroughly mixed. Apply with a soft left in the after the spirit has Logwood Extract, 2 oz. of Crown Soap, 8 brush and polish with a woolen cloth. been consumed. Contributed by oz. of Softened Glue, 1 qt. of Vinegar. S. G. ROBT. H. GYSEL.

www.americanradiohistory.com THE ELECTRICAL EXPERIMENTER November, 1915

Our Amateur Radio Stalin,, 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 lute not to publish photos of stations unaccompanied by that of the owner. hark photos preferred to light toned ones. We pay each month $3.c0 prize for the best photo. Make your description brief. Address the Editor.

AMATEUR RADIO STATION MR. GITTELBAUER'S RADIO SET. others are home -made. The transmitting CONTEST. Mr radio transmitting set comprises: A apparatus comprises the following: One - K. W. transformer, 2 units each 1/a K. inch spark coil, rotary and open spark gaps, Monthly Prize, $3.00. W., plate glass condenser, fixed gap, oscilla- two Leyden jars, helix, key and necessary This month's price winner. switches. For receiving, I use successfully a loose coupler, two loading coils, variometer, two RADIO NIAGARA STATION. variable the condensers, one fixed condenser, The accompanying photographs show silicon and galena detectors, 2,000 -ohm radio Niagara station and serve to clearly head -sets and buzzer test show of the ap- to out detectors. the exterior appearance My aerial consists of four wires, each 95 so only a brief description of paratus, that feet long, spread 2 feet apart. It is 55 feet details need be given. high at end 45 feet high is one and at the The complete receiving equipment other. I also have a smaller aerial for home- made, having been built by myself. sending. The war has effected the tem- ln the rear of the audio') cabinet is a porary closing of my station. I lo 1 ratio transformer for the amplifier. Mr. Oittelbauer and His Neat Radio Set. BERT ROUTLEDGE. In place of the flashlight cells, which arc Sydney, C. B., Canada. so commonly used with the auction. I u -e tion transformer, "Boston" type sending ordinary dry cells which have been dis- key, aerial change -over switch, pilot lamp ROY C. two BURR'S RADIO STATION. carded from automobiles. There are and a protective device across the 110 -volt The following is a description of my line to provide against kick- amateur station: backs. Left: Excellent and My aerial is made up of 7-strand No. 22 Nell- Arranged Radio The receiving set includes: Transmitting Set of Loose -coupled tuner, aerial Orrin E. Dunlap, Jr. loading inductance, Audion detector, galena and silicon de- Below: Master Dunlap tector, also a "Crystaloi" and His Home-Made detector with a cohering in- Audion Receiving Set. Note Marble Switch - ductance. Board at Right. Normal sending range 40 codes. Normal receiving range 500 miles, but can copy high power stations 1,201) miles. The aerial consists of three wires (stranded copper) 70 feet long, stretched between two poles 52 feet high at one end, dli feet bight at other end. Ground: Three pipes, each thriven 10 feet into moist earth. Aerial when not in use is grounded through a standard loo- ampere knife switch. I hold a first grade commercial license, in addition to amateur license, and am a member of the American Radio Relay League_. My official call is "2 A. Y." FRF.DK. GITTELBAUER. Excellent Radio Equipment of Roy C. Burr. sets: 44 cells in a set. The tuni..g ap- East Rutherford, N. J. paratus is mounted copper cable, 65 feet long and 50 feet high, on a separate mahogany AMATEUR located on a hill. For ground I use a large cabinet and can be used as a portable set OUTFIT OF BERT if necessary. ROUTLEDGE. copper plate buried 10 feet in wet clay, also With this set I have heard gas and water pipes. For sending I use Colon, Key \Vest and many other distant I give you herewith a photo and descrip- stations. 888 watt Thordarson transformer, 6 Mur- dock condenser sections, Blitzen rotary, The transmitter consists of a i.i -Ii. W. W. Blitzen oscillation transformer, Precision H. transformer, rack type condenser, meter and 2 resistance rod kick -back pre - made up of 10 double flint glass plates. cop- Only venters. All connections are of heavy four plates are employed on / K. per bar and transmitter is mounted on plate \V. The oscil:ation is transformer the glass base. 1 K. W. glass plate condenser . \MCO type. The rotary gap is of the of own con- Clapp and rotary quenched gap my Eastham type. struction are also included in this set. I worked I. Z. L. of Northampton, receiving set constitutes the follow- Mass., My regularly throughout the winter. ing; 2 .01 M. F. variables, type D Clapp - The signals have also been heard in Vine- Eastham tuner. R. J. S audio') and galena land, N. J., Waynesfield, O., and at Ann detectors. Switch is provided for changing Arbor, Mich. from audion to galena or vice versa. Five The aerial consists of six wires, 85 feet Blitzen duplex loose coupled loaders in- long. 70 feet high. Radio Station of Bert Routledge. crease the tuning range considerably. ORRIN E. DUNLAP. JR. tion of my wireless station. Some of the With the above set I have listened to a Niagara Falls, N. Y. apparatus is of commercial make, while the number of stations very clearly, including www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 3 .1

such stations as 2 J.D. (New York City), delivering the proper or exact amount of WIRELESS STATION OF 8 Q.J. (Detroit, Mieh.), 9 B.D. (Superior, current to the filanient, the bulb will sud- C. E. LAWSON. Wis.), 9 S.N., and many others. denly begin to oscillate, and 1 can then pick Herewith is a picture of my wireless re- This is a star station for the American ceiving set and aerial, which I hope to see Radio Relay League, and also a member published. of the Central Radio Association. Any ex- The receiving set eomprises the following perimenter who would like to communicate instruments: 2,+du0-meter loose coupler. with this station is cordially invited to do ,),000 -meter E. I. Co. loading coil, Junior so, my call being 8 R.D. fixed condenser, 3,000 -ohm "Electro" Norwalk, O. ROY C. BURR. amateur head set, "cat -whisker" galena detector, Murdock fixed condenser. Audios WIRELESS EQUIPMENT OF HAR- detector. pole- changing switch for throw- OLD C. SNOW. ing quickly from one detector to another. Herewith tender photos of my station I "Electro" baby switch for breaking crystal : and myself for entrance in your Amateur detector circuit when using Audion, and Station Contest. also marble -base lightning switch (not The aerial utilized is of the "L" type. 90 shown in illustration ), in order to conform feet long and 50 feet high, composed of 8 to underwriters' rules. _\udion batteries 'copper wires 2 feet apart. The receiving are concealed in drawer of table. All set comprises a lurdock loose \ coupler, woodwork is mahogany finish. On the right rotary variable condenser, Perikon and Sili- end -ohm of table will be seen my wire telegraph con detectors, 3,000 head -set, and load- set. ing long, waves. \Vith set coil for this I The aerial consists of six strands of am able to hear N.A.A. at all (Arlington) "Antenium" aerial wire, is 30 feet high at times of the day, and have frequently re- one end Sit 7:, ceived signals from N.A.N. Pan- and feet at the other end, (Colon. feet long and connected loop ama), N.A.R. (Key West, Fla.), N.A.W. fashion, "i." type. in order to get the maximum wave (San Juan, P. R.) and N.A.W. (Guan- length for receiving from high -power sta- tanamo, Cuba), as well as many other Gov- tions. Aly is No. 4 ernment and commercial stations. ground copper wire soldered to water pipe, and is about The transmitting set is composed of a feet long. Blitzen type % -k.w. capacity oscillation Efficient Radio Station of W. O. Homer, on Which Time Signals Are Audible So \\ith the above set I can hear, any night Feet from 'Phones. in the year, the time signals from Arling- up several undamped wave stations on the ton. Va., and Key \Vest. Fla. f have also Atlantic and Pacific coasts. heard the Sayville, L. I., station at night, at \V. O. HORN ER. Cleveland, Tenn.

STANLEY CARROLL'S EFFICIENT RADIO OUTFIT. The following is a description of my wireless receiving station located at Marietta, O. My set comprises an "Electro" professional loose coupler. A Murdock variable condenser and its silicon detector, No. 322, with condenser inside it, with i' tr suitable capacity, and the "Electro" load- /VA 1:- t ir,'vt ing coil. My range at night includes Key \Vest and Arlington. My aerial is of No. 14 wire, 112 ft. long, of four strands, with 7?2 ft. spreaders. 90 ft. high at one end, 65 ft. at the other. Aerial points west- Particularly Neat Radio Station of C. E. Lawson. ward. Am going to build a new aerial this fall just twice the size of my present one, favorable times of the year, and can hear and intend to get a is kilowatt sending set. the U. S. Naval stations at Charleston, STANLEY W. C. \RROLL. S. C. ; New Orleans, La. ; Savannah, Ga.. Marietta, Ohio. and Beaufort. N. C., as well as various Harold Snow Finds His Radio Set of Great Interest. hear -by and smaller amateur stations. This is, I consider. a very good record transformer, glass plate condenser and for so small an aerial, and I believe is due sending key; a quick throw switch is used to the fact that all my connections are to ehange from receiving to sending. soldered and the wiring as simple and I have a First Grade Amateur License d`rect as possible. and my call is 4 G.A. I shall be very I would like to exchange photos of my pleased to hear from any other wireless set with other amateurs. operators. CLARENCE E. LAWSON. HAROLD C. SNOW. Cleveland, Tenn. Swampscott, Mass. NEW RADIO CLUB IN BANGOR, W. O. HORNER'S TRIPLE VALVE ME. STATION. The Penobscot Radio Club, of Bangor, The photo herewith shown depicts my Me., was organized recently and the fol- new transmitting and receiving station. My lowing officers were elected :. Harold station comprises a 1 -k.w. Clapp -Eastham Grant, president; Roy N. Johnson, vice - transformer, condenser, rotary spark gap. president; William J. Anderson, secretary improved oscillation transformer, hot wire and treasurer. ammeter, kick -back preventer and Blitzen The other members are: William Hall. wave- meter. Cornelius Sullivan, Wainwright Reed and With this set I have heard Arlington Edward Frey. time signals during the clay Vi feet from All the members have up -to -date appa- the 'phones, and the 10 P. M. night signals ratus. Meetings are held weekly at the as far as 90 feet during cold weather. home of the president. The club members The triple valve audion receiver case is would like to communicate with other solid mahognay. I have been experiment- Stanley Carroll and His Wireless Set. radio clubs and exchange photos of ing with the 1st or tuning audion, and find amateur sets with other amateurs. Ad- by placing a permanent magnet around the Do you realize that with his issue The dress all communications to William J. bulb on a line with grid and wing and by Electrical Experimenter contains 72 pages? Anderson. 122 Lincoln street. Rango". Me.

www.americanradiohistory.com 4'RTE5T Px:ITENTS

A. C. Massage Vibrator. An improved form of stethoscope, Search =Light for Revolvers and talking telephone receiver arranges (No. 1,149,099; issued to Leo J. utilizing the well -known dictagraph Guns. an electromagnetic circuit in the Wahl and Edward W. Wahl.) principle and therefore being of re- (No. 1,149,705; issued to Eugene S. shell of same, as perceived. The The patentees of this device in- markable. sensitivity. The specially Ward.) diaphragm 5 is resiliently mounted tend that it shall be used on alter- arranged micropbone and controlling A modified form of electric flash- and is actuated so as to reproduce nating current circuits and in this rheostat 8 co -acts with a loud talk- sounds by means of a lever 25, con- ing receiver 5 and the vibrations of nected to the soft iron armature 24. its diaphragm are reproduced acous- The position of the fulcrum lever tically through the tube and ear 22 may be adjusted, and it is thus pieces 6.' A small battery, of the seen that owing to the difference flashlight type 7, provides current in leverage thus obtainable that it is for this system. The inventor possible to greatly amplify the move- claims that several parties can listen ment of the armature 24. Thus it to the heart beats and also to the is possible to make a satisfactory actual character of the beats simul- electro -magnetic telephonic repro- taneously; owing to the greatly ducer. Also the pole 14, of the amplified' strength of the beats, as electromagnet 21, is adjustable as to reproduced by this dictagraph appa- its position, as will be observed. way a vibratory electromagnetic ratus. A much desired improvement force is caused to act from the it seems. Electric Pilot and Night Lamp. electromagnet coil 15 on to an iron (No. 1,147,949; issued to Eliot armature 16, which is attached to a Electric Dry Battery. Keen.) pivoted, spring mounted, arm 17. (No. 1,147,753; issued to Leo T. On the end of the arm is a rubber applicator cup 19. The operation of the device is self- evident and it is x. =;5`sr;. ..4tÌii - .ri' very simple, magnetically con. light with small size sidered. battery, which may be contained iii the handle of a revolver, Portable Electric Trouble Lamp. etc. The flashlight bulb is placed in a metal tube attachable to (No. 1,148,662; issued to Oliver C. the under Dennis.) side of a revolver or gun. This tube has a sliding tube on This invention provides for a small same, so that the lens which it car- electric trouble lamp, suitable for ries can be focused for the best use about automobile engines, ma- Schatzei assignor of one -half to results in any case. Oscar V Maurer.) A new style of dry battery cell Wireless Antenna. made up in the usual manner, as (No. 1,147,010; issued to Reginald illustration shows. Improvement con- A. Fessenden, assignor by mesne sists in using as a depolarizes a assignments to Samuel M. Kint- persulphate of one of the following ner and Halsey M. Barrett.) metals; Barium, strontium, ammoni- ,r um, coppers manganese, calcium, sodium, lithium or potassium. Of these, however, potassium t,ersul- phate is the salt of persulphuric /I acid which produces the most marked results. Such batteries yield 2 volts and the life of the battery, as well as its recuperative powers, is said to be well above that of any common cell heretofore manufactured. Complete formulae are given in the patent for making tbe entire cell.

New Wireless Head 'Phone. This patent covers a special form of pull socket in which the pull cord (No. 1,148,941; issued to Harry B. is arranged to comprise a flexible Wier, assignor to Western double conductor. To the end of Electric Co) this twin flexible pull cord is at- Several good features are in- tached in a protective casing or corporated in this patent for an im- cage a small pilot lamp 4. Either proved wireless head telephone re- the large regular lamp 2, or the small pilot ceiver. Firstly, the receiver is This patent covers in considerable or night lamp 4, may adjustable to practically any posi- detail the special form umbrella be switched on by alternating pulls desired, by means the swivel of on the cord 3. tion of antenna for radiotelegraphy, as used frame and trunnion 35 and 36. by chine a Prof. R. A. Fessenden, at the work, etc., and includes Brant Rock station in Electric Sad Iron. strong magnet coil mounted in the Massachusetts. (No. 1,148,627; issued to The illustration shows how the va- Edward E. base of same. This magnet coil 12, rious guy Rose.) is connected wires 16, spaced radially in multiple with the about the 400 -foot New style' of electric sad iron, electric sup- steel pipe mast providing lamp itself and is thus 11. form a part the aerial e very neat and efficient plied with current from a common of proper. The entire mast rests on an insu- battery, such as that used for igni- lating glass tion on the car. The core of base 14, and the patent central covers methods for either using or the coil 12, is - of iron, as is also not using the steel pipe mast as part the outside shell surrounding the of the coil. The aerial system. Also powerful magnetic flux passes out spring shock or mechanical tension ¡I]Ìr,!l'llM of the core 1t, through the ironi absorbers 76 are mentioned to be body, on which it may happen to inserted rest in each guy wire, so that at X, and so back into the the mast will have great flexibility : econd pole face, comprising tbe and resilience, outer shell. mechanically considered. The guy wires are, of iJ2 course, highly insulated, as becomes Electric Stethoscope. evident in view (No. 1,147,282; issued M. of the fact that to Kelley they form a part of the antenna proper, Loud Speaking Telephone Receiver. (No, 1,152,536: issued to Albert Moffatt.) S. Secondly, the magnet poles may be adjusted to a greater or less distance from the diaphragm by means of a sliding thumb nut 26, attached to a threaded base plate 10, adjustably mounted inside arrangement for leading i;' the the receiver shell. The nut 26 can double conductor cord. The double be clamped at any position desired conductor cord passes through a and the receiver is thus adjustable protective spring 22, adjacent to the for different signals and frequen- insulating handle 5, A connection cies. Further, the cap 9 and the block 6 is placed within the hollow inside shell 5 may be removed from handle and two lead wires run down Turner, assignor to General the base shell by means of a through the hollow handle frame 4, Acoustic Co.) bayonet joint 29. The patentee of this new loud. to the heating element 7. COPIES OF ANY OF THE ABOVE PATENTS SUPPLIED AT 10e. EACH. 350

www.americanradiohistory.com Novenlbcr, 1915 THE ELECTRICAL EXPERIMENTER 35I Phoney Patents Under this heading we will publish hereafter electrical or mechanical YOU THREE DOLLARS ($3oo) FOR THE BEST PATENT. Il you talcs Ideas which our clever Inventors, for reasons best known to themselves. your Phoney Patent to Washington, they charge you $x0.00 for the have as yet not patented. We furthermore announce the grand opening Initial fee and then you haven't a smell of the Patent yet. After they at the have allowed the Patent, you must pay another $20.00 as a final fee. That's $40.00 I I WE PAY YOU $3.00 and grant you a Phoney Patent PHONEY PATENT OFFIZZ In the bargain, so you save $4.100! ! When sending in your Phoney Patent application, be sure that it is as daffy as a lovesick bat. The Por the relief of ail suffering daffy inventors in this country as well daffier, the better. Simple sketches and a short description will help as the entire universe. our staff of examiners to issue a Phoney Patent on your Invention la We will revolutionize the Patent business Immmedlately and OFFER a jiffy. PHONEY PATENT OFFIZZ U. R. WRIGHT OF WHEREATIN VA. No. Umsteen hundred and forty 'leven. BOOKWORM'S NURSE Pat. applied for 10 minutes 'fore lunch. Specification of Phoney Patent -Application Sandpapered September the Tooth To those who- cousarn it all, here goes: electric cell. (The Bluestone image, after umbrella is automatically let down to it's I, U. R. Wright, of the Burg of Where - months of constant use, will acquire a like- normal position. atm, Va., do hereby swear dreadfully, and ness to William Jennings Bryan.) The Strapped to the chest (if he lias one) of affirm firmly that I have invented means electric current thus set up actuates a the victim is a small electric fan in circuit whereby and by which a confirmed Book- switch which cuts in the storage battery with a thermostat so when it is warm the worm may be relieved of all thermostat starts up a delightful anxiety about reading too late at mountain breeze. night, getting wet in the rain, get- Reading so much a man is likely ZINC ANO COPPER STRIPS ting overheated or run over by F-TEDDY to forget to wind his watch, so an vehicles. electric watch is provided. Injury this wonder- csPsé to the eyes by reading in Full description of STORAGE BATS o- too dim a ful apparatus follows: - light is prevented by a selenium cell, LOSOP yE A small but powerful dynamo is which in dim light releases a switch strapped to the small of the back. .ss operating an électro- magnet which On each end of the shaft is an PEPPER --A pulls a lever to and fro rapidly, on aluminum flywheel covered with the end of which is a pepper fly -paper and having teeth around shaker. This shakes pepper in the the inner edge of the rim. Pawls eyes of the reader and thus calls fastened to the legs of the wearer a halt. engage these teeth and spin the While crossing the street, inter- dynamo when the victim walks ested in a book, one pays no at- along either fro or to, hither or f UMBREL tention to approaching autos and thither. The current thus gen- cars. A sensitive microphone worn erated is led by small wires to on the person actuates a spark, storage batteries concealed in the which explodes a bomb tinder the high stove -pipe hat which goes with coat tails of the bookworm, heft- fitted ing him gently into the air, while the outfit. So a man, thus MICROONON' J'SAFETY FIRST"I out, really has "bats in his belfry." THERMOSTAT' \\ SAFETY PIN J the said vehicle saunters non- The top of this hat is the most in- ELECTRIC WATCH chalantly on beneath him upon its genious part of the whole mecha- E-YE BOMB wonted way. nism. It consists first of a shallow INDUCTION COIL, To prevent reading in bed too hard rubber pan, shaped much like late at night, a 10- pound mallet is a friction tight molasses bucket lid. fastened in the umbrella socket, In this lid are laid narrow strips and at the appointed time the elec- alternately of copper and zinc, tric watch connects the circuit and these being connected in parallel. the mallet descends upon the On top of this is an image of Theo- noodle of the victim, giving 40 dore Roosevelt, rampant, carved swift swats, knocking him insensi- from a lump of copper sulphate or ble till morning, when he is awak- bluestone. More about this later. ened by a shock of 10,000 volts Between the shoulders of the un- from an induction coil. fortunate is an umbrella which nor- An Electro- Mechanical Dingbusted Nurse for "Bookworms." In testimony whereof, I have mally hangs down, closed, behind hereunto appended my nom -de- him. On the handle end of the feather this day, O Lord, presetve umbrella is a segment of gears which to the motor which hoists the umbrella. Lis from further attacks. Now the There is a tiny hole in the bottom engage with a small motor. of the U. R. WRIGHT. action is thus: When a shower starts. hard rubber lid or pan which contains the and the Bookworm is ambling along, face zinc and copper strips so that the bluestone By his attorney, solution very buried in a volume of "Deadwood Dick," trickles slowly out, and down STANLEY H..COVINGTON, the rain drops trickle over the Bluestone the back of the wearer's neck. For this Lynchburg, Va. image of "Teddy," partly dissolving him reason the patient must wear blue acid and covering the zinc and copper strips proof overalls. When all of the solution Witnesses : I. B. Darn. W h o o d a with bluestone solution, thus forming an has run out, the switch is released and the Thoughtit, Ischga Bihble.

INVENTION TO DETECT PRES- tions caused by the machinery. The ap- WIRELESS SYSTEM SAVES 500,000 ENCE OF OTHER BOATS. paratus will work effectively, it is said, re- LIVES IN A YEAR. of Buffalo, N. Y., gardless the number of ships within its W. Lorenz, a jeweler of the value of the wire- has succeeded in perfecting two valuable in- operating radius. The other invention has Fresh evidence of the not made less as a saver of lives has been found dur- struments which have been accepted by been public. of disasters navy. One of the inventions is ing the disasters and threats Canadian following in the wake of the European war. known as a "ship detector" on which he NEW WIRELESS STATION AT has been working two years. Repeatedly the Atlantic Ocean has been The detector makes it possible for a ship CHELSEA, MASS. combed by wireless in its sending of warn- properly equipped to ascertain whether On Sept. 15 the new wireless station at ings to threatened passenger ships. Al- other boats are within a certain distance, the Naval Hospital, Chelsea. was opened. though no figures are at hand, a wireless their direction and approximate location. It will be the most powerful on the Atlantic operator has just estimated that not fetver The instrument works on the principle of coast. The station at the navy yard will than 500,000 lives that would have been wireless telegraphy. The vibrations of a not be dispensed with, but will be run just lost before the invention of the Marconi ship being detected are communicated to the same. The new station cost in the system have been saved by it since the be- the receiving apparatus through the vibra- vicinity of $125,000. ginning of the present year.

www.americanradiohistory.com 352 THE ELECTRICAL EXPERIMENTER N uveunber, r915 ITESTION 150X

This department is for the sole benefit of the electrical experimenter. Questions will be answered here for the benefit of all, but only matt- - of sufficient interest will be published. Rules under wnicn questions will be answered: z. Only three questions can be submitted to be answered. 2. Only one side of sheet to be written on; matter must be typewritten or else written in ink, no penciled matter considered. 3. Sketches, diagrams, etc., must be on separate sheets. Questions addressed to this department cannot be answered by mail.

MEASUREMENT OF FREQUENCY grant shows how the E. I. Co. automatic Tuckertoft, N. J., uses a Poulsen arc oscil- IN A. C. CIRCUITS. storage battery charging cut -out works. lation generator of about 60 k.w. rating. (345) F. Callahan. . wants to You may experiment with this form of Data on this and other powerful stations know how the frequency of an alternating - cut -out, and in designing the coil windings in this country is given in the Government current circuit may be measured. you should allow about 1!11111 circular mils "Radio Call Book." procurable at 15 cents A. I. There arc several ways of meas- area of copper wire for each ampere which from the Superintendent of Documents. uring the frequency in cycles of alternat- is to pass through the coils. Hence you Washington, D. C. ingcurrent circuits, but the usual and most can very easily design the coils by referring direct method is that utilizing a standard to a standard -ß. $ S.. wire. gauge, as given LOADING COILS. "frequency meter" of the direct -indicating in most electrical catalogs. (349.) R. A. de Vore. Atlanta, type. One of these. of the vibrating -reed While one size of cut -out with certain wants to know the number of turns neces- type, costs about $li5 for frequency measure windings on same will take care of a sary on tuning coils 3 inches in diameter monts sontetvhat above and below fill cycle. dynamo anti battery outfit somewhat higher to obtain the longest possible wave length r hotter in voltage than that which it is with an aerial :I110 feet long and 50 feet FREAK RADIO RECEPTOR. high. He also wishes to know the maxi- (316) J. \I. Butcher, Aledina, O., ex- 0111111111111111111111111111111111111111111111111111112 mum additional wave length he can receive plains ;tow he has picked up radio signals by using a loading coil. on a telegraph sounder without any de- A. 1. There is, generally speaking, no tector. to Swap? limit to the wave length you can receive A 1. in most cases that have come to Want by using large coils; that is, you can wind our attention and along the line you men- if you have anything to buy, sell a coil to feet long, but such large coils are tion is has been found that the armature or exchange and want to make not properly proportioned. A properly bar, etc. (of the telegraph sounder, for insure of doing it quickly and at an constructed tuner has a length that is equal stance), has been so adjusted that it insignificant cost, advertise in the to about four times its diameter. A coil formed a tuirrophuuic contact which would of this size, 12 inches long and 3 inches in pick up wireless signals; or also tt would Scientific Exchange Columns diameter. wound with Xo. 24 wire, in con- act as a reproducer of speech under certain OF nection with your aerial should have a conditions. wave length of about 2ri011 meters, and you Quite possibly the dead wire circuit run- The Electrical can add loading inductance both in the ning from the sounder acts as an aerial, E x p e r i m e n t e r aerial circuit and the detector circuit to and wireless signals have been repeatedly raise this wave length up to 7,000 or even picked up by using a telegrapli or tt.lephone You will find advertised in 10.0011 meters by using coils large enough. circuit as an antenna. these columns: The usual practise is to put a condenser -s across the secondary circuit to increase its I Photographic supplies, Phonographs, stave length. BATTERY CHARGING CUT -OUT. Apparatus, Electrical goods, Roche, Lafayette, N. Wireless (347) L. J. Y., Bicycles, Motorcycles, Rifles, Gasoline inquires about making a battery charging Engines, Microscopes, Books, Skates, CONDENSERS AND RANGES. 1 :3:',11.) A. l'eck, N. J., Typewriters, Etc. I'aul Plainfield, F. asks several questions: I. Whether glass The owners of these ihings wish plates can be used in receiving condensers. fuses to "swap" them for something :L The wave length of his aerial. 3. The fie/o' else, something which you may distance over which he can receive with his have. apparatus. 4. how far he can transmit .. tt-ith a buzzer outfit. The Rates A. 1. Glass plates can be used for re-

I One cent per word (name and l' address to be counted) minimum Au/omo/ic cut oui` space 3 lines. Average 7 words agate to the line. Remittance fie/d regulator must accompoh all orders. zuzzer Nó/ overn-is fee/ The Classified Columns of the ELECTRiCAi. EXPERIMENTER

GET RESULTS IIIIIIIIIIIIII More than 40,000 Electrical Ex- perimenters will see your ad. ;l luumuununumuuuuuuuunlfuunul designed fi r. it becomes necessary to re- Buzzer Used for Transmitting Radio Signals. wind ;he coils especially for the dynamo varies 20 to 4-.5 feet .4 to be used when the dynamo ceiving condensers and are suitable for such 25 per cent. above or below the rating of purposes, but their disadvantage is that they the cut -out. are rather bulky; otherwise they are superior to those made from paraffine paper. THE TUCKERTON, N. J., RADIO A. 2. The wave length of your aerial, o.PST- sw Lamps STATION. 80 feet long. 20 feet high, with lead -in 1.5 Jiv feet a wire 20 feet long. 0 347 (343) James S. . Washington. long and ground D. C., asks what form of high- frequency would be approximately 160 meters. N Iring Diagram for Storage Battery Lighting generator is employed at the Tuckerton, A. 3. We do not snake a practise of Plants. N. J., trans -oceanic wireless station oper- answering questions regarding the range cut -out for accumulator plants. ated by the Goldschmidt interests. over which wireless sets will receive, be- A. I. The appended lighting plant dia- A. 1. The powerful radio station at (Continued on Pate 354.)

www.americanradiohistory.com November, 191 ; THE ELECTRICAL EXPERIMENTER 333 READ EVERY LINE . a

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This 1-6 N. W. Closed Core 56`.95 ! HERE IT IS AT LAST W Ireless Transformer.... . Electro -Set "Navy" Loose Coupler After months of a periment.< mud utter making tierr ' N ' Loose Cou ter or Recel In Trap fn, is ...mot elligna id ale,, we have lhmllY Fnarur, l equal ,f aboost any brae eoueler, ne :utter who. k - - -- 6 the price you formerly hod to ray for sm,n its price. It is certaii4yy far xnlx'riur Many we have seen at tt anywhere ' - ,n ile and h hrirs, f ww manear price. Think of being..w .11.0'o/rem, , Tlx pile of n items will weir me tins ,invent m oci nv " Ìta.xo motAer n hew pore t 1, this 'Inalrart,en1 Jwlx, Gino, did toot ',spore , K.N. e y It wins +l ec,fie1rtnI nx Ile unittL.Jn'1r,I iÌ,invaI sip . F erg spotlit the money; for , ss, nr rd nwndarnwen: I I .rJ robberdd seen.. 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We Are Agents For Electro -Set "Arlington- Tested" Crystals MARCONI USED APPARATUS Electro -Set "Famous" Mineral Sets Scud 5c. in stamps for new', intert.ttug OR,OI.tlOia.mt interwting li Ode in wireless telegra pity When testing out a wireless receiving installation, for the able rxnarimeminc with rannne combinations and met hods first time you want to know that your mineraln crystal is sere catalogue of used Alarcuni Wireless Insl rte nf'ortnet ill let err ors. We off er the follow ingouthteepr.- aitive. Then to w4v l ny minerals on nnl le. Be sure meats at ridiculously low prices. V., are 'illy designed for this outpost, and packed in neat box. oft results -good results. Bur our "Arlington Tested" agents for this line and can ship promptly Countless tours of interesting experimentingisaoi°red to Crystals. Every our is tested for Arlington time signols. the amateur a it h this set. anything from a Type "Ii" Ritter to ;1 'il,di,r It includes live dill Brent minerals Each crystal conies sealed In an it tight glen, phial and is t;e neratur. (galena. silicon, curbnrw °Ions. borulto and tnsl ybdem.m t. ea efully tested l leaving our factory. Only one ergs- each packed in cent glass bottle: one universal detector tal in 20 D ur examination. Arlington Tested - cup; three lie ce pbmpor- browse cuteWhisker" wire: one Crystals arc the meet genii tire you Can. procure. They are worth the price. Each one polished wood detector base: one large binding post; one hard rubber knob; one brake is individual] ye samiued n it packed. riel wi t h holder for wire. With t hiso.,t fit it is possible to make 11141Y diff erent kiuds of NO. 301 ARLINGTON TESTED GALENA. individually packed and tested; rw.tpat, .. 50.15 detectors. It is ideal for the ex Perim enter. 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Polarlr!d Ringers-New, n used. Complete Telephone Induction Colts -Nov aged. Wm I Telephone Relay Coils -Wennd to IIx, Ohms with Tap ,d far $.a9 co- Worth 4e. ea.. new. 2 +el o ash árromnee magnettcolts wo and with silk to Ia Uhms lute, prism, and et,,atlnry earls, silk aimco ilk covered w n l:onmhtc with moot it S p is I !a w,. I.r de. 1SC. ,Postage a, .,me strong to ro,xmnt n,a,enel with rlwzer. ,ell wbu. Exe.Ihmt ah.akins coil can be ,1a Wow alp worth 20c. Special price. ea. Morsee Shoe Magnet -" n lone .ry powerful - Wor h 60c ea. Any experimentcr en use on,. With one. Wrath :Ale. ea. Special price ea. 09e. Ó8e. Pest:,ge4r., n vet aÌ for many experiments arid for makote in. Spey al prim, ea '15e. il'O.taet se .,m 4e Connecting Bbeks -Hard vhh. size 711n. o 1 ...meats.. Worth 15e. each. Special OSe. ,+. price Hard Rubber Knobs-Sire le-0118 x In. Milled Binding P st -Ha oleo ,ell nickeled n.13 in. x 1 x 3.16 in. Have 1i hele. tin, e32 ma,h n I l'nslave.'te., and Tapped foro;l2 aerew. Ilamty for making up- in. or all. Ì:,m,il.ne nwi I, n . Worth 6e. en. Complete with 'screw sWorth 12e. ex. mnt Here's A Dandy Chance-We have mole pare us. Worth' ., new. Special Price. per Special price, per ,k.... 25e. ..,. 2'a., 1'mtage µr 04e. lI'ottsp, lc , lilt of raves of ama Ì1 odd parts of rh'rtñvl it t. 10C. (Postage Je.,`w d rz. 5e.) Hard Rubber Handles -,, in. n ii In. brilleol and vet ,m.xn that enery experimenter coil ar in his

12 .r0; , N 13 14 Uttltt , i , . t ,. a I) .

" shop. These boxcsmch contain from 40 to00 paces entaax all want them. Y o can loathe dunes with 4 nuts and ,news with connectors. Werth with them. Worth 60r. Ir. Secs) price with of . ids and end., such as rubber knolls, braes of things wilt them. Ì5r. ea SeeingJ price. e.. 05e. ',e.tacr 2e.1 ke, per emir 09e. l'ottaave Sc., attn bogs. hooks, binding pasts, novwu. nits. No. 121- Ilmuly Assortment. Prepaid 20c. Connecting ode of genuine hard rnhlwr Toy Motor Parts .ens in of on Iron ca nuts, 7S Ohm Receiver Coils-Never sod. Ready e, ìíh :t hamlxame nirWÌr.l binding p,stx. U .lid ith ode Vir.xx; 2 covers for . and one :liege thomh roils and mioettuncaa war ts. Sumnave ° frdacn of things about the exerime. r'sahn r'mnatedarmnture with haft. ÄIIYou need .. mew asp but an of are useful to have PP1 i, to Y J,bum a kv s a win' tY They - , W' untl toaW5 ohms wept silk wi e. W eCl ra .,. have never le. used. gra:Mai mnrater. twwrtngs.nmt wire te complete m15e w'ltrnY ranking ommto The ore .., L Ì , Te 2r., ÁÉ11, a t. worth 40c. set. Special 1Se. ... pte.) pur I,nìr, ith e c fora a ', price. jst thefromkin uconvconvenient parts to be able to ioi+iage te'l Relay per Telegraph Ma netset situr n titian Corti,ge first choose forr youreae, arinients, We've old nave hem mosi but a .reel shape. wising 40e. mmatatar wire for above motor. extra ndred, f them in our retail department. F'. v- COnneeting'8loeks Viol.. f een,rine hard rubber, to MI 01111. rexixtunre 'Raike relay or telegraph 40c. l(Yremhl.t EAST 110 THE ELECTRO -SET CO 1874 ELAND, 'OHIO

you brnriif by mcntininn "TIn Flr,tri'el 7[.rn.v' nti r" col,, n ;t'ritino to a. tr'rr risers. www.americanradiohistory.com 354 THE ELECTRICAL EXPERIMENTER November, 1915

cause there are so many factors governing this. It is impossible to make more than YOUR RANCE a haphazard guess. A. 4. The buzzer transmitter set illus- DEPENDS ON YOUR trated will transmit about half a mile ,\ under ordinary conditions, but distances as ,, high as five miles have been covered with .-- RECEIVERS . \ same. A prominent New York firm is i \yi Tiine about to market a buzzer which they claim will cover distances of about 100 miles. 0.353 AERIAL AND GROUND. (331.) Wallace Green, Hackensack, N. Three -Phase J., asks: L The effect of the height of an Alternating Current Waves. aerial above sea level. 2. The effect of wires, and the peaks of the currents are grounding wireless apparatus and a tele- 120 degrees apart; this will be understood phone on the same water pipe. from the drawing. It gives a sketch of the A. 1. The height of an aerial above sea current waves in a three -phase circuit. As level will have a tendency to increase your to the best motor to use, it depends on the range, but not in direct proportion, as it is purpose to which the motor is being put. the height above the ground which deter- A three -phase motor has been found to be mines to a great extent the range. Tit's is very practical, but requires quite an elab- due fact into to the that waves propagated orate starting system ; it has a good start- the ether have a tendency to follow the ing torque. This motor is what is known surface of the ground and not to continue as the induct' on type; that is, the fields in the same plane as the station from which and the armature have no electrical con- they are emitted. nection. The two -phase motors operate on Holtzer -Cabot A. 2. The effect of grounding wireless the same principle, but the windings are apparatus and the telephone on the same wound in two separate coils, not connected. Radio Receivers water pipe will not be noticed unless the The single -phase motor is generally of the 'phone wires run very close to the aerial. synchronous type; that is, it starts as a have honestly In that case a large part of the energy series -wound direct- current motor, but on earned their from the transmitting set will be absorbed reaching synchronism with the supply cur- by the wires and will cause annoying noises rent the connections to the armature are reputation of in the receiver when using the 'phone. automatically cut out and the motor oper- being the ates in synchronism with the alternating RADIO QUERIES. current supplying same. "Most Sensitive Receivers Made" (352.) W. B. Jones, Hampton, Va., asks: 1. For a hook -up for a transmitting appa- Other features are light weight, comfort- HORSEPOWER QUERY. able shape, durability. perfect finish. Send ratus and receiving apparatus. 2. If he for Booklet 20 D2 for description. (354.) Felix Washakas, Chicago, Ill., desires to know the horsepower of a motor THE HOLTZER -CABOT ELECTRIC CO. required to move 100 pounds at a rate of 1,320 feet per minute on a level surface, BOSTON - CHICAGO and the amount of current it will take to run the motor. I A NEW CHAMBERS COUPLER A. 1. As you do not give any clue to friction in your letter, we PRICE ONLY $6.00 the coefficient of LOOK No. 744, have figured out the required power of Positively un- if the weight was being lifted vertically. e qua led for the money. Is It would require a 4- horsepower motor to 6" high, 6" :move 110 pounds the required number of wide, and 14" feet per minute in a vertical direction, but over all. is mounted on wheels Wound with if the weight or E namele d rollers the power required will drop to wire, and has about 10 per cent. of this amount. It will a very unique Radio Transmitting and Receiving Hook -ups. require 28 amperes at 110 volts to run the slider. Wood- work mahog- can pick up Sayville and other such sta- 4- horsepower motor, and if the power is to any finished. Try one, you will not be disap- tions. 3. The stand:ng of the Dodge Insti- be applied horizontally the amperage will pointed. drop to 2.8 approximately, and the horse- 5c. in stamps brings our 64 -page illustrated cata- tute of Telegraphy and Radio. logue, B-11-24. None otherwise. A. 1. Attached drawing shows the power to .4. Street method of wiring transmitting outfit, using F. B. Chambers & Co aephi,dl2046 quenched gap, 14 -inch spark coil. Hook -up AERIALS AND RANGES. for your receiving outfit is also shown. (355.) Edward Jones, Fairmont, W. Va., A. 2. We cannot say positively if you asks several questions: 1. The efficiency of "Mignon - can receive Sayville or not, but would ad- the spiral aerial as compared to that of the vise you to listen for signals when the straightaway. 2. The wave length of a System" which is 8 and Pareses Anvtiee station sends press, between spiral aerial 14 inches in diameter, 60 feet or 11 p. m. long, which contains 800 feet of Antenium R C 2 A. 3. We are assured that the Dodge wire. 3. What is the time of operation of has $20.00 Institute of Telegraphy the best that the Sayville station. 4. What high -power . A Marvel in can be obtained in equipment, and its Selectivity and stations should he be able to receive from. Efficiency. faculty consists of experts in the line they 5. The advantage of a large capacity vari- are teaching. TheRADIO. Last Word able condenser. APPARATUS. A. 1. \. Te have had no experience with a n'rit. for A. C. MOTORS. aerial. From reports, we believe it sns lets a sí5:6 isCasa Lit. rature spiral (353.) Earl Meldrim, Fort Edwards, to be very efficient, but for all -round MIGNON - WIRELESS CORPORATION N. Y., inquires the difference between one, amateur work we advise the construction Specialists m Radio Signal Receiving Apparatus a straightaway aerial, as it has given N. Y. two and three -phase motors, and which are of 127 W. Market St., ELMIRA, the best to use. great satisfaction in the past. A. 1. One -phase motors operate on an A. 2. The wave length of the spiral NEW SAYVILLE PHOTO alternating current circuit that posseses but aerial containing 800 feet of wire will be 1,400 COMPLETED MASTS one wave; that is, it reverses at stated pe- between 1,200 and meters. SHOWING THE ELEVEN NEWLY is still in operation, but is 13 of them 500 feet high). Also two detail riods. The two -phase circuits generally con- A. 3. Sayville Inserts, sbrwing buildings, etc. -3 in 1 -Size sist of four wires, and the phases are 180 under U. S. Government control. It sends 618 in. Mailed M roll, ready for mounting 2be. evening from 8 to 11. postpaid. Send stamps. Ask for free wireless degrees apart ; that is, the current in one set press every catalog. of wires is at maximum when the other is A. 4. You should be able to hear the CHRIS. M. BOWMAN at minimum. The three -phase current con- N. A. T. and W. H. E. Marconi stations at . Box 104 LANCASTER, PA sists of three waves combined on three (Continued on page 356,) www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 355

'Iti2Ttrmlu4 F2215?arrt1' GATSI O nou a.. k ef E t".w X N G FOR THE EXPERIMENTER" IN THIS a THE OUST CATALOG IN AMERICA" "THE L WEST CATALOG IN AMERICA" THE ELECFRO IMPORTING COMPANY CARRIES TILE LARGEST STOCK OF EXPERIMENTAL, ELECTRICAL AND WIRELESS GOODS IN TILE WORLD. II'e are the originators of the Wireless Experimental business in the U. S., selling the first wireless outfit in 1001. Our wonderful facilities enable us to give you delivery in 24 hours. WHEN ORDERING GOODS FROM THIS PAGE ENCLOSE POSTAGE ELSE GOODS MUST BE SHIPPED BY EXPRESS COLLECT. The goods shown here are only a small part of our entire line which is fully described in our 275 -page Cyclopedia Catalog, which weighs y lb., is 6Mx5M inches in size and contains 2,000 articles, OSS illustrations, 30 diagrams and El tables, full Morse Continental and Navy Code Charts, besides "Treatise on Wireless Telegraphy," list of call letters of all U. S. Gov't and Com- o mercial ship and shore stations. This wonderful Cyclopedia sent free if you send us 4c, in stamps or coin to corer' postage only. WE SELL MERCHANDISE, NOT CATALOGS. "Why buy Catalogs when the best is f,cc ?" Use coupon below to send for llrtalg, enclosing 4e. for postage only.

+-'^-- a añ^.goy- a Boy Scout Knife. IL,. 2 Upright Caloric Engine. Smallest Flashlight Made. Telegraph Key. (rouble Inter -Ocean Wireless Re- Wireless Detector. Ururr- excellent Quality steel Rune by hot air. Simplest Nickel case, tungsten lamp. circuit. Rubber comp. base canting Outfit. Has loose nteed to receive long dis- blades, stag handle and a model engine possible to long life battery. Gives a and knob. Has three rub- coupler. galena detector, Jr. tance messages or er rep chain to guard against construct Is very durable. very powerful light, is very ber comp. binding posts. fixed condenser and 7000 me- back. Base hard rubber lose. Chain is detachable No steam or water used. handy and fits n vest Metal parts nickeled. Size ter loading roil all mounted e D. Metal parte nickeled. 3', 6'5:4'5. Size 21,x1Lx11.16, 255X355.. A Iena crystal su plied Sire $ at will. Length in. Size All cylinders Pocket. wonderful value. and connected on polished tse r. Our Sb, wt. 4 ounces. of brass. Sh. wt. Sit. wt. 4 ounces. $.50 Sh. wt. 1 pound. oak hose. give lOxl2x 2 Pelee 50.7 lbs. Price $.95 Pn ee P 7 Price P$.35 u' .. Sh, wt.11l I br. Price D'erimiwith 0 o NMI

Rugby Football. Made of Dynamo. n vodts, lo am- Rheostat. l'orccLain Bas, X mas Tree Lighting Out- Hustler Motor. Buns n Revolver Ex. (l'et -a,. Resistance [0 ohms. Flashlight. Pebble gram leather, lined peres. Very heavily built for fit. For 110 volt house cur- lerfully on on a dry cell. act model of automatic - with duck. Bladder guar- a to.ltg., charging batteries, t eulym leavb leefoedm n,ing rent. Has 10 colored lampe, Will operate small toys. v lver. shoots brilliant light anteed against accident, electroplating, etc. Excel- red, blue, white and green, beautifully finished and when trigger ie r teed. Con - wear or abuse for one year. lent power motor on 8 volte, 1 tp diatermin.) 4 ches tontrl-ole.. very strong. A wonder for talus tungsten lamp and bat- Most wonderful value made to last. We sxl'sxlÿ by 1 ko . Diseonneets on ,Absolutely sale and corn lete the price. Size 3x3x4 tery in handle. Surprise your oefite. d. Standard SI, wt. 20 lbs. $9.00 ber eomp. Sw2h $ 60 ,1h rout and plug. Sh. wt. I pound. friends. Size 422'i $.95 .c sh. wt. 211,, $90 ls. Prise nh.a L.I lbs. I'ri's $40S`P Price $.85W iuc Sli,WL l lb. s a 0

Electric Lighting Outfit. Radio Ni B Dynamo. Vcry powerful, Free Wireless Coures cou Telephone Receiver. "Nand Lamp. Fite g volt 150 watt capacity. ln- Gives 3 rolls and is same size gives 6 volts 6 amperes, Mating of 20 lemons, total ohms. Hard rubber comp. on any dry cell and ll eludee switch as standard No. 0 12 generator, dry cell. lights, tungsten lamps, 160 binder size powerful magnet. With two burn for 50.75 hours. wNo board with meters, etc., if Wonderfully efficient, Made charges storage cells, runs page, cloth receivers and no battery, danger and always ready. li. P. gasoline gins storage of extra blab grade materials. as a power motor, Not 7:10!4 in. with 350 illus. 30 500 a battery, [urea. wire, belt, bydro- etc. you can talk feet. Size Supplied complete without Coed for lanterns expp i- toy. lochs.. tables. Coupons for this meterandpiana.Cs- and a Size 6x6x6 2'f r 1'4 inches. Shipping battery. Reflector is ad- a Sb. mental work. Size. @ ./[ Sh. wt. 7 pounds. 'Free Wireless Course t 1 pound. ïnstable. Size 6x3. /, $3.70 $40 pwt. 185 lbgh'er $74.00 2., 8 b.wt. 3 lbs. Price APP Price lo Ur C'o'lupe,fin ecia Sh wt. 'r lhs. l'rire. .75 3352 .(1- t. o o Upright Steam Engine. Trolley Car Outfit. \Vou- Pocket Ammeter. Rouge "P " Bicycle Lamp Spark Coil. Orves 1 urrb Printing Press , s. II lu, Has water gauge, whistle, derful value, will run ou dry 0 3 ampere.. Pockets (electric). Operates almost lia uniug spark ou t. volts. Mg). will print u form of large balance wheel and will cells. Outfit consists of trol- Finely nickel plated, accur- 5o hours oit une dry cell. "_ Lull Dog" style that's cop- x3)4 iu. Includes Sa fout, ley car, controller, electric ate, dependable and handy. inch reflector is fully adjust- ied but never equalled. Oak of 175 characters, type case, troleum. Tested before ship - headlight and 1555 feet of Invaluable for testing dry able. Fastens on handle bars. trame,platinum points. Rub- gold and silver broze. unk. eot- nt. Directions included. stra ight and curved track. cells. Diameter 2h inches. Battery container included but no ber binding with structions. p. posts. Dto ds e Sh. wt. $.95 siselextlx4. Sh. @@ Net weight 45, o battery. Perfectly $1.15 Size 7f4a5tixh%. &A .00 $3.00 111bs. HPri e w6 10 lbs. Price....PStPO Sh. wt. 1lb. Price $80 safe. Sh.wt.:lbe. Prie, Sh.wt, 8 lbs. Price YIPT élx P'ceSSwttx THE ELECTRO IMPORTING COMPANY "EVERYTHING FOR THE EXPERIMENTER " Write your name 236 FULTON STREET, NEW YORK and address in the Margin below 0 o o 1== iN You benefit by mentioningwww.americanradiohistory.com "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com November, tos TI-IE ELECTRICAL EXPERIMENTER 35ír

to us that the vibrator has a tendency to weld the contacts together. This may be due to the condenser across the vibrator having become disconnected in some manner, thus causing undue sparking. As a rule vibrators stick due to either using too Multi- Audi -Fone much current or not having a large enough primary condenser connected across the The new wonder in the wireless world.. It increases the Audibility 1,500 Times vibrator points.

ANTENNA QUERY. (358.) J. Scott Wilson, Piqua, O., sends Read What Others Say us a drawing of an aerial he intends to Messrs. Stickel & Stickel, of Connellsville, Pa., say: "We have given your apparatus a construct, and wishes to know the advan- thorough test and find all that you claim them be." tages of this type of aerial. that they are to Mr. D. L. Irvin, Pa., says: was the results from it. A. 1. Your aerial possesses no radically of Curwensville, "I surprised with Arlington and several other stations came in so loud that I could read them with the ' pbones new features except the rat -tails, which are ten feet from my head." separated by means of a spreader where Sir. Ralph Hatcher, of Toledo, Iowa, says: "The results were even more than were the lead -in is connected. This gives no dis- expected, both at the convention and by other amateurs in Des Moines, who tested the tinct advantage, and we believe it will be apparatus, and other places." better if you group the rat -tails 15 feet Mr. John Tucker, Jr., of Elizabeth, N. J., says: "After a thorough trial. am astonished away from the aerial proper. at thr results obtained . . . Combining, as these instruments do, the greatest degree of efficiency coupled with extreme compactness, they are, without doubt, the finest instruments cllered tt. the amateur and professional wireless field at large." your -Fone A W. U. Horner, of Cleveland, Tennessee, says: "I have been trying Multi- Audi SIMPLE ELECTRIC CHAIR. out as an Amplifier . . . I was more than surprised at its sensitiveness. It is certainly (359.) D. Causey, Greenville, Ill., asks: wonderful. . . I stood at the rear of my store, one hundred and twenty -five feet from 'phones, and copied Arlington and Key West, also Tampa, Florida. I consider that some 1. For the dimensions of a coupler, the amplifying for way down here on Inland." coils to be stationary, using switches for tuning. 2. Where he can get a good tan- gent galvanometer. 3. If it is dangerous to operate a receiving outfit during a thun- FIVE OH M derstorm. RECEIVERS Never use more A. 1. The dimensions of a coupler of the 014E TEST ran oat tel\ BAT type you ask About can comprise two coils CELL BUZZER at% eettecy 6 inches long, the larger one to be about DET. 4 inches in diameter and the smaller to be about 3% inches in diameter. These are wound with No. 24 and No. 28 wire respectively, and are mounted one within the CRTSTA Lalo other and leads brought out to the switches PUSH DETECTOR in the usual manner of wiring these BUTTOly- couplers. A. 2. You can get the address of the GROUND firm handling galvanometers from the advertising columns of The Electrical Ex- To ust the l'tlu\lum- AERIAL perimenter. in-Yoavo vitthout The MULTI A DI-FONE A. 3. It is very dangerous to operate a ' 1twlti7AeätTVA ADJUSTMENT receiving a as SWITCHES set during thunderstorm, the tmmntT 740 o}tm TUNING HANDLE aerial acts as a lightning rod and will draw the lightning into the station, and the op- tetàtvtts to lists under these conditions is in erator danger (T) =° (T) tSHo of electrocution. MULTI--AUDI--FONE ELIZABETH, N.J.

CHARGING STORAGE BATTERIES. 1 (360.) Raymond Johnson, Potter, Neb., Multum in Parvo wishes to know: 1. df Storage batteries Receiver, inctudtng Crystaloi Detector and Buzzer - $20.00 can be charged by gravity cells. 2. What Multi -Audi Fone, including our Specially Wound Head Set - - S30.00 size of w:re to wind a five -bar telephone The Matchless Christmas Present. Our Complete Wireless Set, Only - $50.00 generator with to obtain 6 volts. 3. If he can make a good wireless ground by fastening the ground wire to a driven well 256 feet deep. Talking Multi- Audi -Fone j Telephone VoicE Multiplier A. 1. Storage batteries can be charged by gravity cells, but it requires a long time for them to be fully charged. You should use sufficient gravity battery to give about 2 volts more than the storage cells for proper operation. A. 2. By winding your magneto with No. 20 wire you will be able to get about 6 volts from same, and you can regulate the voltage by changing the speed at which you drive the machine. A. 3. Fastening the ground wire from your wireless set to a driven well will give Size, 4A:" x 5" x 7 ". Size, 2'" x 3%" x 434". an ideal wireless ground, as you are mak- 'rbe amplification is so great with the Talk- ing connection to moist soil. The Telephone Voice Multiplier has been made ing Multi -Audi -Fone that the signals can be possible by applying the principle employed in read all over the five -story building from our our Multi -Audi -Fone to the telephone receiver. laboratories, which are located on the third The voice can be distinctly beard coming over LEAD SALTS AND THE X -RAY. floor. If the windows are opened, the signals 1,000 or even 2,000 miles of wire that would can be heard across the street, even when the be indistinct coming over 100 miles of wire. (361.) Eric C, Peters, Pennsgrove, trolley is passing. Buy a Multiplier and stop straining to get N. J., inquires: 1. If all the lead salts have Prise, Including horn - - $100 something you can't hear. Price SI5.00 the effect of stopping X -rays. 2. Whether radium rays can pass through lead, or are reflected from it like a mirror. 3. He also Send for circular today 213 Morris Ave. asks several questions regarding the length Ask your dealer to- morrow ELIZABETH, N. 1. (Continued on Page 359.) MULTI -AUDI -FONE

1 www.americanradiohistory.com 358 THE ELECTRICAL EXPERIMENTER . November, 1915 i BUY YOUR XMAS WIRELESS NOW BIG REDUCTIONS FOR NOVEMBER ONLY Save 25 % If You Act Quickly Here is Your Opportunity to Secure the Best Navy Type Loose Coupler on the Market. Regular Price $15.00 $10.00 For November Only- Reduced to A brass lacquered 6,000 meter inductance tuner, perfect in every detail. Equipped with four Point loading inductance which increases the wave length 4,000 meters over tbe average Navy 7'ype Transformer,. The primary winding has 24 taps-one switch controls tbe primary in groups of tens, the other controls one turn at time -and is equipped with a dead end switch. Enclosed in a cabinet, the front of which is polisbed hard rubber. Tbe secondary coil is wound with double silk covered wire and the inductance is varied by a ten point é itch. With tbis coupler the very finest and most accurate tuning is easily and quickly secured. With a good sized aerial tbe recep- tion of wave lengths up to 6.000 meters s possible. All Finished Parts Ready For Assembling With Full Instructions - - - S6.50

Our No. 810 Complete Sending and Receiving Station Receive The Time From Arlington Sends up to 12 miles. Regular Price $20.00 AND ALL NEWSPAPER AND SHIP REPORTS Receives up to 1,000 OUR SPECIAL TIME $8.10 SIGNAL RECEIVING OUTFIT miles. FOR NOVEMBER $14x00 REGULAR PRICE $10.85 ONLY This is our new T 1915 model made Full l S5'inch coil type. Send up of the highest to 12 miles. Receives up to 1,000 grade material miles under favorable condition,. o h t ai n alit e. Equipped witb 2 double pole 1,000 Double slide obm receivers, 6 feet silk cord and coupler for close double headband. Sine of bees 12 a tuning Is wound 16 Inebes, height 13 plebes, weight with No, 24 only 14 pounds. green silk cover- This is a completely equiequipped and ed !citable ,linon, mechanically eÌsugno-electric- wire on the ally perfect and ready primary the instant service. secondary - with hing better per this class ever construct - No. 28. There new are 8 points to g u to turc divide Its capac- desire. its. A 3,000 -metre loading coil placed between the coupler thus eliminating any in- and the aerial by a switch that throws it in or out of the terference. The set con-e sists of circuit enables you to receive amateurs with the coupler alone o. Flat PlateSCoon- and long wave stations by the addition of the loading coil. One Out r Detector, Buzzer fixed condenser of proper capacity, improved universal detector, Switch to tell if your one buzzer test to test your mineral, and potentiometer. This dandetector working, on a highly finished oak base. All Double Slide Silk Wire instrument is assembled Wound Tuner for long metal parts are heavy nickel -plated. This station, with our Navy Type Loose Coupler, as Illustrated Fixed C ndenser,pHelii' combDPDT Switch above, $15.00 Ohm Ìleadset.

OUR No. 401 SENDING AND RECEIVING STATION Regular Price - - - - $5.95 $4.95 FREE! For November Only - Complete Gem Station Consists of y4 -inch coil, fluted end Receives uD to 900 miles. spark gaps, four plate secondary, one We will give absolutely free a Gem Outfit to every one collapsible helix, one key, a two -slide wbo sends us the cost of the tuner, fixed condenser, detector and necessary equipment for it. Tbis equipment consists of buzzer test to test your mineral. This 2000 Ohm Headset 53.95 16 Insulators .48 set is mounted on a highly finished I Ground Clamp .10 oak base with all metal parts heavy 500 Ft. of A -1 Wire 1.20 20 Ft. of Rubber Cable for lead in .90 -plated. -sized nickel With a good aerial, TOTAL $6.63 under favorable conditions, will send up Send SC 63 at once and we will include the Gem Receiving Station to 3 miles and receive up to 300 miles. Free. A splendid outfit for beginners.

Send 6c. in Stamps for Our Big 152 page Wireless and Electrical Catalog "H -80" Containing Hundreds of Wonderful Bargains of All Kinds Nichols Elect. Co., 1 -3 W. Broadway, N. Y. Manufacturers of Standard Quality Goods Only

You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 359

QUESTION DEPARTMENT. straightaway for sending, as shown in the (Continued from page 357.) July, 1914, issue of The Electrical Experi- LEARNING TELEGRAPHY menter on page 44. of the wire used in an article on the tele- A. 3. A carborundrum detector requires graphone that appeared in the June issue a battery of about 3 volts and a potenti- of this magazine. ometer for its proper operation, as it re- A. 1. It has been found that a mixture quires a close regulation of the voltage to of granulated lead and linseed oil is the get this detector adjusted to its most sensi- best lead salt to use in making garments tive condition. that will protect the X -ray operator from the burning effects of the X -ray. Any RECEIVING TUCKERTOI4. cloth may be used for this purpose, but (364.) Max Clinch, Lakewood, N. J., silk, being of such a fine texture, retains asks several questions: 1. The use of a the salts much better. tikker on damped waves. 2. Regarding de- A. 2. Lead is opaque to all the radium tectors. 3. Schedule and wave length of rays and acts as a screen, absorbing them the Tuckerton station. and having very little reflecting effect. This A. 1. It is possible to receive time sig- applies likewise to X -rays, as you may no nals from N. A. A. (Arlington) by using doubt understand if we mention that a lead a tikker, but it has been found in actual salt is used in making the gowns to protect practise that a detector responds best to slightly damped waves. You should use e simple when your instructor is the Omnigrapb the operator. Automatic Transmitter. Combined with a standard key and A. 3. The telegraphone was actually the tikker when receiving from stations minder or Wireless Sumer, it will send you telegraph m which use undamped waves, such as Tuck - oa expert constructed for experimental purposes and the n Ling of operator as yousbecome more pro - 200 erton or the Federal Wireless Telegraph t Adopted by U.S. Gov't. Made in 4 styles. from only feet of wire was used. You may $2.rnL50 up, all acourate. Ci,rular free. use any length of wire you desire by in- Co., which use the Poulsen arc system. creasing the size of the spools to hold it. A. 2. It is generally admitted that the Omnigraph Mfg. Co., 39 L Cortlandt St., New York You will be able to purchase steel wire galena detector is the most sensitive of from any dealer in electrical supplies, and mineral detectors, while the ordinary PHILADELPHIANS he would no doubt be able to quote you Audion, particularly when used as an ampli- prices on small gear wheels. fier is really the most sensitive extant. KNOW US A. 3. The wave length of the Tuckerton You, too, should earn BLOCKING CONDENSER. station is very high, about 7,500 to 8,000 meters, and it has no special time for of our large stocks of (362.) Frank Haverland, Jr., Madison, Electrical and Wire. operating, being a commercial station, but Neb., wants to know: 1. The wave length, can be heard nearly every evening about lose Apparat s. and in- power and time of operation of the Fort 11 o'clock. telligent service. As Omaha radio station. 2. Correct capacity agents for The Electro for a blocking condenser to be used with a Importing Co. and J. H. loose coupler. HOOK -UPS. (365.) Clifton F. Taylor, Waltham, Bunnell & Co. we as- A. 1. W. V. H. is under Government Mass., asks for a hook -up for a wireless sure you of qual- ownership and is likely to operate at any outfit. ity merchandise time of day. The power, we believe, is at lowest prices. A. 1. Q. No. 355 shows the proper about 3 kw. and operates a wave length wir- on ing for the apparatus you mention, of 600 meters. but we would suggest the addition of a variable Quaker Light & Supply Co., phr,hPat: A. 2. A blocking condenser for use with condenser to your outfit. This condenser a loose coupler should have a capacity of is shown in the drawing and increases .075 M.F. If the 'phones are connected it across the condenser the flexibility and range of the station it is advisable to utilize vastly. an adjustable type for this purpose. LINE INDUCTION AND VARI- AERIALS AND LIGHTNING PRO- OMETERS. TECTION. (366.) Casimir H. Jaraszewuz. Chicago, (363.) Allen Sjoholm, Chicago, Ill., Ill., asks several questions: 1. Whether a asks: 1. How a loo aerial can be connected to a S. P. D. T. lightning switch. 2. Which type of aerial is best for sending Only $5.00 and receiving -a loop or a straightaway If you would like to get louder signals, make aerial. 3. If a carborundrum detector re- your station more selective and receive longer dis- quires a battery for its successful opera- tances, get this efficient Receiving Transformer. tion. Send two-cent stamp for Bulletin 105, just out. A. 1. A loop aerial cannot be connected to a s'ngle -pole double -throw switch for Colby's Telegraph School, Auburn, N. Y. lightning protection, but by adding an extra clip as shown in the drawing it can be done. This protection call then be afforded "Construction of the by wiring the switch as shown. A. 2. It has been found that the loop Audion Amplifier" aerial is superior for receiving because it with working drawings. particularly de- is a closed circuit and does not reradiatc scribing the transformer. Price, 50 cts. received energy, while the straightaway aerial is better for sending because it does THE MISCELLANY, KANSAS CITY, Ñ1Ó. not require an anchor gap in the aerial. Variometer Hook -Ups. WIRELESS LooPedoer/o/ current of 4,400 volts used for railroad OSTON work would affect a wireless set located Boston Receiving Transformer, 57.50 LOMniny Variable Condenser, 25 Plates, Si./5 ., - - 200 feet from the said circuit. 2. The prin- B D 51.25, 4.00 Boston , 51.00, 51.75, $2.25, _i ciples and construction of a variometer. Agent for Electro Importing Co. and A. W. Bow- A. I. Since your aerial is located at man Co., Manhattan and Adams Morgan Spark Coils, Ever -ready flash lights and hatteries. right angles to the wires carrying 4.400 Catalog for stamp only. volts, it will have little or no effect on M. MUELLER, 18 Devonshire St , BOSTON, Mass. your set beyond a humming sound that may be slightly noticeable. A. 2. Drawing shows two connections 1 for a variometer. The first illustrates a Microfarad Condenser variometer used as a loading coil, and the cast in metal box with 2 binding posts. Insula- tion good for 800 volts is Looped Aerial Lightning Switch. second how it used by the Telefunken Regular Price, 57.00; Special Price, Co. for tuning purposes. A variometer for cash with order $2.00 You may arrange an aerial switch so that consists of two concentric coils of wire, Rosenthal Laboratories, Camden, N.J. you use a loop aerial for receiving and a each containing an equal value of induct- You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com 360 THE ELECTRICAL EXPERIMENTER November, 1915

anee. The inner soil has a knob fastened carry a very complete line of Wireless Apparatus in to it, so that the planes of the two coils WEstock, being Chicago headquarters for the Electro may be changed. The two coils are then connected in series, and when placed so Importing Co. Same prices, same goods and Free Wire- that tliey help each other ; that is, so that less Course. The Static Machine shown here is an their respective magnetic fields are assist- example. Just turn the handle and get 2 and 3 -inch ing each other, the inductance is at its sparks. Price, $3.75, No bat- highest value. As the inner coil is slowly turned out of the plane of the outer cols teries required. We also the inductance changes, and when turned carry a complete line of through an angle of 180 degrees the two Electric and Auto coils will be opposing each other and the algebraic sum of their inductances will be Supplies. zero. Send 4c. In stamps for our 3 complete IVo. 10 WAVE LENGTHS. catalogs. Tungsten (367.) W. J. Gravely, Danville, Va., inquires: 1. About the stations that have the Flashlight same sending range as the Arlington sta- 6 inches long, complete, 65c. Extra bulb, tion. 2. The wave length Sayville 's now Price $3.75 15c. Extra battery, 25c. using. 3. The sending range of the Wana- No No. 125 Tungsten, Nickel Vest Pocket Flash- batteries light with Tungsten bulb and Ever -ready battery maker station in New York and its wave required. complete. 49e. Extra bulb, 15c. Extra battery, 25c. length. Nitrogen Lamps are the latest type of Electric light and use 507c less current than the old style lamas. they ' A. 1. Stations on the Eastern coast also give you he ice the light for the same current. having a range equal to the Arlington sta- PRICE LIST' tion are: Sayville (W. S. L.), Key West 60 Watt. $0.90 400 Watt. $4.00 (N. A. R.), A. 100 " 1.00 500 4.50 Colon (N. X.), Tuckerton 200 " 2.00 750 " 6.01 (W. G. C.). 300 " 3.00 1.000 " ...... 7.00 A. 2. Sayville uses a wave length of Se nd 4c. in stamps for our 3 complete Catalogs and bargain about 2,800 meters, of ra c, material and lesson cou p'n and sends "press" to ships from 8 to 11 p. m. daily. A. 3. The Wanamaker station, New York (W. H. I.), uses 2 kw. and has a sending range of about 250 miles under all Winger's Closed Core Transformers conditions, and operates on a wave length of 600 meters. 14,000 VOLTS Perfectly Insulated. INVESTIGATIONS IN LECLANCHE 1% K.W. $10.75 PRIMARY BATTERIES. K.W. 15.90 A new and commercially valuable in- % K.W. 10.50 f K.W. 25.50 vestigation of the construction and chem- Designed for direct connection, ical reactions of the Leclanche cell, the no volts 6o cycles without resist- form of primary battery used so extensive- ance or impedance. Send 6c. for ly big new catalog. for ringing bells, buzzers, etc., and in dry cells operating portable flashlights, WingerElec.& Mfg.Co. bells. igniters, etc., has been undertaken by Ernest G. Crocker, of the graduating class 711 So. Dearborn St., in electrochemistry at Massachusetts Insti- CHICAGO, ILL. tute of Technology. The polarization was found to be due to an alkali effect of ammonia, previously A New, Finished Complete Receiving Set referred to as hydrogen, and experiments Efficient, Beautifully were LOOSE coupled. complete receiving set, pri- made with different sizes of the secondary grains of materials contributing the dry wound with very fine silk covered Sec- ondary divided up by ten taps which are battery, and various ratios of one of the brought out on end piece, contact being made materials to the other for efficient work. by it phosphor bronze rotary switch with a hard rubber knurled knob. A specially constructed It was found that the fineness should be detector allowing a very fine adjustment is one of the features of this station. between 1/40 and 1 /100 of an inch, and A fixed condenser of the exact capacity, spe- contrary to the custom of some manufac- cially constructed for this sise loose coupler. turers, the two constituents greatly adds to the efficiency of this outfit. All should be or parts built of solid oak and mounted on a solid the same size. The materials used are oak base, beautifully finished. carbon This station will be nt complete as described and pyrolusite, and the quantity of with one 60 ohm double pole receiver. headband the latter should be about 60 per cent. of Send stamp for our wireless catalogue, and the whole mixture. free code chart of unbreakable fibre. Mr. Crocker found the best material for 19A East 32nd St. All "Universal" outfits are sold with privilege removing the alkaline effect is chloride of Universal Wireless Co. New York City of 10 days' trial and money back guarantee. zinc. The practical result of batteries constructed according to the formulas de- duced ELECTRICAL EXPERIMNTER FOR from the experiments is that they A BOUND VOLUME 75e. will remain more in Bound in substantial green cloth; lettered in gold. Postage on 3 lbs. is extra. Book Department. A constant current pro- REAL BARGAIN. EXPERIMENTER PUBLISHING COMPANY, Inc.. 233 Fulton Street, New York. duction under light continuous use. You Can Only secure the best in FLASHLIGHTS and BAT- TER I ES by insisting that this trade -mark is on flash- Beacon FLASHLIGHTS and : light -case and battery. If your BATTERIES are made in a á dealer cannot supply you with wide variety of styles and our product write shapes but only . directly to us for ' _1 CíXija,ll:nlni-T one quality - Catalogue A2. I - THE BEST. Ñ "Ideal Fountain Light." ils BEACON MINIATURE ELECTRIC CO., NEWYORicsT BRANCHES: CHICAGO, SAN FRANCISCO

www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 361 PATENTS THAT PAy OUR TRADE -MARK A OVER $600,000.00 MADE BY CLIENTS r PATENTABILITY TWO WONDERFUL REPORT BOOKS FREE: Edited by H. GERNSBACK Send sketch or model of E at( tied "Inventors your Invention (orfree Guide" 1146 pages) anti In this Department we will publish such matter as is of interest to inventors search of the "What nod How to In- and particularly to those who are in doubt as to certain Patent Phases. Questions Office Records and re- micthpreof of Fortunes addressed to "Patent Advice" cannot be answered by mall. Sketches and descrip- port neto patentability. in Patents" (127 page.) be clear and one side of sheet should be written on. tions must explicit. Only Highest Rdereflees, including 100 manufacturers serve. Telephone Lock. understand that while the article was a PROMPTNESS ASSURED (28) Henry Lewis, Toronto, Canada, very meritorious one, the company went out Across the Street from the U. S. Patent Office has submitted a model and sketch of a of business as there was probably not suffi- CO., WWashington, ó telephone lock and desires to have our ad- cient demand for the article. A large ad- E. E. VROOMAN & h : vice if it is patentable and whether it is a vertising campaign was carried on, but it r practical apparatus; it is to be used in seemed to be of no avail. PATENTS AND TRADE MARKS locking telephones so that unauthorized Incandescent Lamp. parties cannot use it. (32) Alfred Schneider, Boston, Mass., A. We have carefully inspected the lias perfected an electrical invention cover- LANCASTER & ALLWINE model and drawings and find that as far as ing an incandescent lamp and he desires to B dg. o` Washington, D. C. we can tell the invention is original. We know whether he could go ahead manu- 252 Ouray think there is p good chance to obtain a facturing same or selling it to a manufac- Book "Inventions- Patenting & Promoting" Free patent on it. turer as soon as he has applied patent on Our co- operation with an inventor ie. FIRST, to :d, however, to caution invention; he to help him establish hie rights before he diwiotee the idea We wou desire the furthermore wishes to ANY attorney. SECOND, to cive a frank opinion our correspondent that up to this time know how long it takes an invention to be whether it will pay to patent his idea, based upon our e.tooaive knowledge of manufacturers' wants and facil- telephone locks have not been very popular patented at the Patent Office. itD. to obtain for him a patent which is in ities. Tifi to advise and and they are hardly ever used at all for A. We most strongly advise against do- eality e. valuable monopoly. FOURTH. assistr him in the profiting by outright /isle, territorial some curious reason. ing any commercial work on an invention grants. obtaining royalty. or independent manufacturing of the invention and FIFTH. aiding him to so profit Foreign Patents. or offering it for sale before the patent by conferring with manufacturen, inventore or distribu- has been allowed. It sometimes takes years tor. of machinery. (29) Victor Stefano, Newark, N. J., Before sending a sketch to anyone. sign, witness, wants to take out a patent, and he is par- to get a patent, particularly in an art where and deposit in our fire -proof vault our docment ticularly interested in obtaining patents also much previous work has been done, as, for EVIDENCE OF CONCEPTION in Germany, France and England. He instance, in your invention. You are prob- AND ESTABLISH YOUR RIGHTS wishes to know if we can give him the ably aware that there are hundreds of addresses of some trustworthy attorneys in patents in existence on incandescent lamps these countries. and it is therefore almost certain that it PATENTS A. It is common practise that if you wi :l take a minimum of one year before THAT PROTECT AND PAY take out a patent in this country that you the patent can issue. Of course. this is let your attorney take care of your foreign presuming that the invention is an improve- Books and Advice Free Send eketeb or model for search. Highest Reference.. patents also. Nearly all reliable attorneys ment over something else. If, however, Best Resulte. Promptness Assured. in this country have corresponding at- the invention is radically different from WATSON E. COLEMAN, Patent Lawyer anything existing so far presents a torneys in Europe, as well as the other and 624 F. Street, N. W. Washington, D. C continents, and they are in a position to basic idea, it probably would take quite a do the work better for you in this manner little less time for the patent to issue. than if you sent the patent direct to for- As a rule we would caution inventors not YOUR IDEAS TUnder our plan eign attorneys. to enter into any agreement with any firm PROTEC inventions can be Gun -Flashlight. or individual to manufacture an article protected at low cost during financial strin- (30) Alfred S. Turner, Lynn, Mass., has which has not been patented. Only in ex- gency, or while perfecting or testing commer- treme cially. Square deal proposition with refundable sent us a description and draft of a gun - cases does such a course prove profit- fees and free investigation if you mean busi- flashlight, the idea being that the flashlight able. The reason for this is that very often ness. Send for free booklet and references. is operated by means of a trigger before the first idea of the invention is very crude Milo B. Stevens & Co., Attys., Estab. 1864 firing the gun. and the article in question will stand quite 694 F St., Wash.. D. C. 203 Monadnock Block. Chicago A. This invention is not new and vari- a lot of perfecting. For this reason if an ous patents have been allowed on precisely invention is given to a manufacturer and the same arrangement. We believe there is he should improve upon it in such a way a concern in existence now that manufac- as to alter the original invention the in- PATENTS WANTED tures revolvers that have a flashlight ventor would have no recourse in case the Write for Our Five Books, sent Free to any manufacturer desired to manufacture the address. "What to Invent" contains List of mounted underneath the barrel, and from Inventions Wanted, with full information re- this you can see that there is hardly a article in question without paying the in- garding $1,000.000 in prizes offered for inven- chance of your obtaining a patent on this ventor royalties. tions, among which are $100,000 for Best Substitute for Gasoline. idea. $50.000 for First Person Crossing Atlantic in Nickel Plating Paste. DODGES HURRICANE BY AID OF Aeroplane. $26,000 for New Substance for Denaturing (31) Howard Armstrong, San Diego, WIRELESS TIP. Alcohol. Cal., has invented a nickel -plating paste and The 85 passengers recently arrived at $50.000 for Best Device for Saving Life at Sea. New York from $10,000 for Machine for Pulling and Topping submits a sample of the paste to us. He Central American and Beata, wants to know whether a formula of this West Indian ports on the United Fruit $10,000 for Automatlo Train Control. kind can be patented and whether such an steamer Pastores wrote their thanks to $10,000 for Improvements in Postal Saralee by Captain United States Government. article is in demand. Henshaw for bringing them home $12,000 for Improvements in Navy Department A. We have examined the paste in ques- in calm weather. by United States Government. tion and find it From the time the Pastores left Port $10,000 for Improvements' in Field Motor that works indeed very Limon Ambulances. well and seems to give, a good plating until she was reported off Sandy $5,950 for Miner's Electrio Lamp. as Hook Captain far as we can tell. We have not made an Henshaw received wireless We have a special department devoted to analysis of the paste to find out what it reports enabling him to keep out of the Electrical inventions and having secured many hurricane's zone. valuable patente in this class we are in a posi- contains, nor do we know if the nickel - tion to advise And assist inventors in this field plating will not peel off in time. in the development of their inventions. There is probably a good chance that a r--"FREE COUPON! ------patent can be obtained on the formula, though we cannot be certain, for the rea- VICTOR J. EVANS & CO., Patent Attorneys son that quite a good deal of this work has NEW YORK OFFICES: 189 -191 Broadway PHILADELPHIA OFFICES: 1429 Chestnut St. been done before. 1 Main Offices: 779 9th Street, N. W., WASHINGTON, D. C. A very large concern a few years as-o 1 GENTLEMEN: Please send me FREE OF CHARGE your FIVE Books as described above. 1 started to sell some nickel, silver and gold 1 powders which gave an electrochemical de- ' NAME... ADDRESS... I posit simply by wetting the powder. We oI You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com November, 3925 362 THE ELECTRICAL. EXPERIMENTER

r111111LLIIIIIIIIIINIILLINIIIItllltllllltll!ILLINIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIIIINIIIIIIIIIIIIIIII BUILD YOUR OWN EDITOR'S 'CHAT. -toys- vaCsNW-- ASK DAD GRANDFATHER'S You will observe that we have in- FOR THIS creased the size of the Electrical TRAIN CLOCK Experimenter once more, the fifth WITH OUR HELP enlargement in seven months. Nor We famish blue prints. finishing material and inet run- are we going to stop, for there will tiops. Buy the works, dial, be a further increase in pages next at and from 0._ f 1E04113: ttgitt . utttl = month. Where else can you find a I i-. prices. You make fine profit similar 10c. magazine containing 72 ock. for your pages, 118 illustrations and 120 Complete works. $5.00. Write Quickly for Our New Catalog Others with chimes at all articles? Where else can you find = price.. telling how you'll have barrels of fun with Ask for attractive free offer. the latest and most up -to -date elec- a Lionel electric locomotive, Pullmans, trical matter and such illustrations freight cars, switches, semaphores, electric Clock Company as presented month in and month lights, track, etc. Make the trains scoot. are Run 'em on batteries or a Lionel trans- 1661 Ruffner St. E out in this journal? You know by E former which saves batteries. (See cut be- PHILADELPHIA, PA. this time that each and every issue E low.) 250,000 boys own them -Join us. Lionel eclipses the one preceding it, and Electric Trains are safe -no shocks. EXPERIMENTERS -INVENTORS you know what to expect. If money They're steel -not Cast Iron -and won't Let us develop your inventions and make and brains can produce a better mag- your working models. azine than ours, we would like to Our well equipped shop and staff of experienced model builders are at your service. see it. LIONEL We carry a complete stock of gears. fLfCjR/C Shipment made same day order received. There will be some distinctly new Send So in stamps for booklet Inventors' features in the December issue, _ Supplies. break. Not high priced. If Your House which we know will please the wire- E Has Electricity UNION MODEL WORKS, Established 1882 Unconditionally guaranteed. Buy This Trans. = less enthusiasts-something entirely Finished hansomely in former 119 S. Clark St.. Chicago new ; watch for it. There will also E colors and gold. be some very original stories, up to E BOYS' BIG our usual standard and even eclipsing CATALOG Experimental and Model Work former ones. FREE ELECTRICAL INSTRUMENTS AND As you see, we are doing our ut- Written ape -r' to give you clally fort' FINE MACHINERY most to please you and YOU, crammed Inventions developed. Special Tools. Dies. the very (best to be had anywhere, full of pictures. Gear Cutting. Etc. and all we ask of you to -day is your Section of Lionel Bail F r e e- HENRY ZUHR co- operation, to make this magazine Most toy dealers, electrical stores and de- 32 -34 Frankfort Street New York City still bigger, still better. Surely you partment stores sell Lionel Toys. Go to your have a or an acquaintance who Toy Dealer, find out if he sells Lionel friend Trains, tell me when you write for catalog BRASS GEARS cut by an perhaps has not seen the latest issue -then I'll include a special section of rail- entirely new poetess. The of the E. E. Why not help the good free. most accurate made and at prices J. Lionel Cowen, A Friend of Boys, President that cannot be equalled by others. work along by sending his name to us Every gear has a hub, center painted ebony black, edges turned TO -DAY, so that we can send him THE LIONEL MFG.CO., ópt. 50, NewYork City true, highest grade red brass. and a sample copy? much heavier than others. We c arry the largest stook in the Also, as we stated once before, we = world, and every gear listed is always eh:pped on date of order. E could never hope to publish such a SEND FOR CATALOGUE = wealth of matter if it were not for S CHICAGO STOCK GEAR WORKS our advertisers. The advertiser "pays 20a So. Filth Ave :: Chicago the freight" and he it is who has E made the Electrical Experimenter Experimental Work at what it is to -day, the foremost popu- Reasonable Prices lar electrical magazine in this coun- TOOLS AND DIES try. Light Machinery Designed and Built. Auto- matic Machines. Cama Cut Exactly to Templet s it therefore not up to you to patronize him to the best of your GEO. SCHWARZ & CO. ability? We strongly urge you to 123 Liberty Street NEW YORK send for the advertisers' catalogs and E Send sketch or blue print for estimate = literature, even though you do not immediately intend to buy. Keep posted, keep up -to -date. Also re- Armature Discs E. member that an "ad" is expensive. AT FACTORY PRICES and for that reason the advertiser is - For Those Any size from 2% inches in to state his to 14 inches in diameter. not always a position Cramped Best grade material with full story in a small space. His japanned insulation on catalog or literature is often as in- Corner one side. Send stamp for circular. . teresting as a magazine and frequent- Jobs- FRED. R. HEILMAN ly more interesting. It is your duty 444 Niagara St. Boftale, N. Y, to possess it. You see it's up to you if you want You need a tool that "gets in" quickly a still bigger and still better mg-a- and effectively. oBuild a WAR AEROPLANE 1 zinc. Can we count on your hearty "Ideal" accu rate Seal inge and knocked down parts support? will enable YOU to build EAS- And lest we forget: Order your MILLERS FALLS ILY exact 3 -ft. Flying Models of those December issue now. It will be a Aeroplanes, now need in the European War. America E Hand Drill No. 306 Must Rely On Her Boys to develop her Aeroplane. hummer! Study Aeronautics. Build a model man- carrying machine. We will send you 3 -ft. Scale Drawings with is designed for just such delicate work. A at following prices: building and flying instructions IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII011111I II111111IIIIIINIIWIIIIIIIIIIIINIIIIIIIG handle of convenient shape contains twist Curtiss Flying Boat 25o :, IIIINIWIIIIIIIIWIIIIWIIIIII70NINIIIIIII Military Tractor 25e drills of all sizes to fit its famous Star Hydroseroplane 35e chuck. Solid steel frame. Nickel plated Nienport Monoplane 25o TO ESTABLISH WIRELESS IN parts encased steel pinions. A beautiful Bleriot Monoplane 15e and Taub' Monoplane 25o NORTH. and efficient tool. Wright Biplane 25o Cecil Paoli Racer 250 To establish a line of wireless stations TO SEE IT WORK IS TO WANT IT Complete Set of Eight, $1.60 Postpaid. JUST OUT- 50-page Aeroplane Book, with full infor- in Southeastern Alaska, which will afford Your dealer will show you or you may mationlion about Model Aeroplanes and Supplies, 5e. postpaid that territory wireless connections with the write for our new catalogue. IDEAL AEROPLANE 8 SUPPLY CO., 76.82 W. B'WAY. N.Y. world -wide wireless service which the Marconi company is planning, is the latest Millers Falls Co. ambition of that corporation. Stations will Millers Falls, Mass. be located at Ketchikan, Juneau, Sitka and N. Y. or r, Ca VENTRILOQUISM Skagway and a low rate night letter service Taught Almost Anyone at Home. Small cost. Bend 28 WARREN ST. today 2 -cent stamp for particulars and proof. between Seattle and these stations will be O, A. SMITH, BOOM B 378, 823 BIGELOW St., PEOBA, ILL established. You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 363 NEW AUTO SEARCHLIGHT WITH OUTSIDE FOCUSING ADJUST- The newest ideas Gold strata case. You've always MENT. cases are yours Guaranteed for wanted a really A new automobile auxiliary searchlight to choose from. 25 years. is provided with an outside set -screw focus- good flashlight, ing adjustment, which permits the use of haven't you? any style lamp either Mazda or Nitrogen, regardless of size or voltage, and makes ONE that won't short -circuit in your it possible to adjust the lamp instantly for kit or go back on you when you any kind of beam without disturbing it in needed it most. any way or removing it from its position. Due to this accessible adjustment, the lamp may be transferred from one car to another of different voltage at will. It also enables the user to select a bulb to suit his requirements, and in case of accident to use any available bulb as a renewal. Should it become necessary to use the searchlight to take the place of the headlight, the width Flashlights of the illuminated field can be increased are quality flashlights - awarded as desired. highest honors -gold medal -at the Another feature of this ingenious search Panama -Pacific Exposition. Give a lamp is the double curvature parabolic re- The Burlington powerful stream of brilliant white flector which, though only five inches in light, just where you want it; con- diameter, produces as much beam candle venient, safe and economical. Guaran- power as any large automobile headlight, teed to give you satisfaction and with even distribution of light. service, Smashes A minor feature but one 'of considerable The Vulcanized Fiber convenience is the design of the handle, Case shown is espe- All Watch Competition light which serves as a stand for holding the _ cially adapted for elec. lamp in an upright position when detached trical experimenters. It ,a_= for repairing tires, etc. ',yam I is the only fiber -case Look: flashlight made which 19 Ruby and Sapphire Jewels- you simply can't short - Adjusted to positions - circuit -a patented wire- Adjusted to temperature- less feature prevents it. Adjusted to isochronisna- 25- year gold strata rase - Insist on a genuine Genuine Montgomery Railroad Dial - "Franco" flashlight. Your New Ideas in Thin Cases. dealer probably lias them in not, write + c stock. If us for an interesting cat - Only w. " alog No. 9. And all 50 INTERSTATE ELECTRIC of this for $2.50 - NOVELTY CO. only $2.50 a month for the A 29 Park Place NEW YORK Month Chicago San Francisco masterpiece of Toronto watch manufacture- direct to you - positively the exact price that the wholesale dealer would have to pay. We do not care to quote these prices here, but write - BOY ELECTRICS write before you buy. Think of the high- grade, guaranteed watch we offer here at such a remarkable price. Indeed, the days of exhor- Knapp Marvelectric Auxiliary Searchlight for Autos. bitant watch prices have passed. Write today. THE GREATEST BRITISH RELEASE AMERICAN .The Newest Casés WIRELESS OPERATOR. In our new watch book, that we will send C. J. Maisch, of New York, wireless op- to you free and prepaid, you will see illustrated erator on we Norwegian steamer Seattle the newest ideas in watch cases. The latest triumphs of the master ,goldsmiths. Notice tÌ9 who ,h and a native -born American citizen, especially the Inlay Enamel Mono ama Block ' had been held in custody since the Seattle and Ribbon Monograms, Lodge Emblems and captured Falkland Islands on Diamond Set Cases. All offered direct to you was near the on this startling offer. Send the coupon today. f 't IËolP. -_ March 14 last, has been released as the . made in his i result of representations behalf by the American Embassy. EXPERIMENTS: NUMBERLESS The plight ,of Maisch was made known See It First! You don't pay a cent to anybody until Finished as shown.n(Demonstrates Sole- in July by the American Minister at Mon- noids. Reeletasce, Magnetism. you see the watch. We won't let you buy a Bur - Motors, Dynamos. tevideo, Uruguay. The Foreign Office in- ngton watch without seeing it. Bold it in your Price $3.75 formed the American Embassy that the hand and admire it. Notice the design, hand- Live dealers everywhere. Order direct, or ask your man had sailed on board the steamer Ban- somely shaped -aristocratic in every line. Then dealer to show you the Knapp Line and insist on look at the works I There you seethe pinnacle of getting Knapp Goods. gor from the Falklands. The next heard watch- making. You understand how this won- Dealers not already handling the Knapp Line should ask for prices. of him by the embassy was a report from der timepiece is adjusted to the very second! Catalogue illustrating many specialties on request. the American consul at Plymouth, England, KNAPP ELECTRIC & NOVELTY CO. who said he had been held to give testi- Free Watch Book 523 West mony in prize court in Slet St. N. Y. CITY case the Bangor, Get the Burlington Watch r which has been renamed the Seattle, ar- Book bysending this cou- Burlington Watch Co'C BDO Y ILn wD e rived in Plymouth in charge a pon now, You will know 19th st. and Marshall Blvd. BOYS! YBO U LMRaATe G G S Oe of prize IS a lot more about watch DepL 3388 Chicago, Ill. A e y t t din baseball and athle- crew. buying when you read ita nnlceinh Ong. please send me (with - --Y carpentry,tryo. stampsstampe and coin it. Youwill be able to rsad ping, steer clear of the out obligations and Drs. N,,,i nit j a dow now d s WIRELESS 1t you ere alt down right pow ant FOR MEXICO CITY. double - priced paid) your free book cm té ? ?, master for urges apbeeilloetr to Boys.goys' A wireless telegraph station has been watches which are with full emplane.. [ Ocapanlon alarga 3apageliluetrated boye erected in Mexico City, according to a no better. Send nonon of your cash or $230 M¿ -1::e- muttthlymagazlne .Itiehoek- tulloitbe the coupon to- a month offer on the Bur - I:. Sp; very beat boys' stories, clean and whole- cablegram received at the Carranza con- Heston Watch. some day for book d `ft' fall of life and action, and bas A] i alt Dlar departments every month on all the sulate from Vera Cruz, and radio com- and our offer. above subjects besides special articles 01 munication between the capital and the out- Burlington tr great ROTS WANT Co. Name ,- ....__.-...._-- -_. ii you wÌÌ1 scud S6 cents a side world, it is said, will be established Watch Ass,. "i.a year'. sabsen1tlo we will melt you soon. Preliminary trials between Mexico Mush15é:á Address "The of S In II" FREE 'City and Vera Cruz have been satisfactory, Dept. 3308 year cents, Rs11 year 16 rents, Three months for 10 rents. Chicag One r SS penlen, 104 South La Salle Street, Chicago, Ill. according to this report. You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com 364 THE ELECTRICAL EXPERIMENTER Y0Ventber, 191 HIGH FREQUENCY CURRENTS. -c°' Solid Oak Letter File (Continued on page 329.) "RED DEVIL" As GOOD As Ever -At a BETTER Price wire motor, and in further tests made by No. 942 / <' S in. Hand Honed and No changes in the construction. -t s Tesla with very powerful apparatus it was workmansbip or finish. Tested Diagonal Capacity 20,000 letters or equiv- found possible to make a device of this alent of Catalogs, Tariffs, etc. Filed Cutting Plier on edge. classified between guide character operate with simply a ground cards for quick and easy finding. connection and the other electromagnet willcut the finest silk in- Drawers are dust -tight and roll on Roller Bearings. Self-locking fol- terminal joined to an insulated capacity or sulation. The standard low blocks hold contents vertically. Each frame joint in- plate suspended in the air. He has also, by electrician's tool for exacting terlocked, glued and N O W this and other arrangements, produced a work. Made drop forged steel. screwed together. Al- most wear- proof. Was $1 2 wireless light which can be lighted at a "No- Pinch" handles of scientific 31$. l . . Freight mid; Three drawers. $10.00; considerable distance from the generating shape give user a firm grip. aelG two drawers $7.75; see station. He claims in his patents that it is Sample 5 in. pair sent for Roc. - finished. BOOK Golden, Natural orryWeeaath easily and simply possible to thus generate LET OF MECHANICS' TOOLS FREE. Birch Mahogany slightly higher. vast quantities of high frequency electrical Freight paidonorderaef5la Smith & Hemenway Co., Note to railway stations energy and to transmit it for hundreds, Inc., lm' w ork Ci ;t- in Eastern and central states. Con- sistent prices in Vest and South. nay, even thousands of miles, where it w.11 "Filing be picked by an elevated capacity or aerial ree l,etSlö filing With 96 -page catalog "F" of joined to a suitable translating mechanism. Office Supplies. Catalog" IC -two SELF - SHARPENER lines Sectional Bookcases and Sec- such as a transformer and motor, etc., hav- tional Music Room Furniture. ing its second terminal connected to earn. FOR SAFETY RAZORS y/r* Swinging Desk Stand as `Yp`w'r1:: A fact not usually considered and which Insert safety blade referenrebooka etc. Fastens to seems to possess considerable promise :n (any but Durham either side of any desk. Swings away when not in use Locks this direction, as well as in many other Duplex), turn handle NOW inner you want g.Oaktop l4xt few times. Hones on stort. enameled met-a lines of electricity's application, is that of and sharpens one e.. al upport, Will nut collapse or freezing the high frequency or other cir- operation; keen cut- by Post , Get one for your desk. ting edge like new. where U.S.: Bee your daim' u write cuits so as to reduce the resistance to an Sent anywhere for $3 The 791,10:' Manufacturing r Company inappreciable value. Tesla mentioned this Money back guaran- 205 Union Bt.. Monroe, Mich. in one of his early patents over 20 years tee. AGENTS New York Office-75 John St. WANTED. IC maid Furs. Co., Ltd.. Hanauer. OM.. Canadian Deakrr ago, and lately very commendable work has been done in this direction by Prof. CIRCULAR EE ON Nammerlingh Onnes. of Holland. By suit- REQUEST. TOY able refrigerating apparatus of special type. tvhrch can produce a cold approaching that IN.MFG. CO., i W. Broadway, New York TRANSFORMERS of absolute zero, or nearly so, it has been ascertained that if induced currents are set 9 Different Voltages up in such a refrigerating circuit, then it is possible for that initial flow of current 50 Watt . . . $3.00 on around that circuit for a very PORCELAIN 100 Watt 50 to pass $4 considerable period of time before it dies "THAT'S OUR BUSINESS" 200 Watt . . . $6.00

down to zero. In some of t:te later experi- 1 Wireless. Bell and ments it was found possible for such a cur- Standard and Special Shapes, Regardless other transformers rent to oscillate around a circuit for many of How Difficult hours before exact measurements with a We Illustrate one hard shape we make. Send for Folders galvanometer, properly joined to the cir- A pair of rolls 73'2" long and 134" in diameter with 8 holes on ends and middle. cuit, indicated that the current had depreci- They must be perfectly straight and we A. R. DARLING ated in value to any great extent. This is make them so. it's hard but not for us. We can make your difficult designs also. 1532 N. Capitol Ave. an important point which as yet has re- Send us blue print for quotations. I ndia napons. Ind. mained undeveloped, and it seems very possible that it could be worked out with Union Electrical Porcelain Works up-to -date and perfected refrigerating ap- Auto Throttle Governed paratus so as to be applied to wireless tele- TRENTON, N. J. Engine for Every Work graph sets, particularly those employing There is no other four - high power, where there is a great amount cycle engine with auto- nigh maticautotypeof throttle of heating and considerable losses occa- Be a DOCTOR of governor on the marketa sioned thereby. As is well known, in such ordnear the price. t nbke CHIROPRACTIC inary low priced en. high frequency circu.ts the resistance plays y:.;rm gi ne. it is not hit -once -i n- governed withir- a very important part, as it acts directly $7S TO $100 WEEKLII a The need now for Doctors of Chiroprac- r-whileegularepaedand wasted with respect to the damping of sue) tic ig tremendous-your a wkppoW tnituxa r Itlfires every shot with circuit. funadvantages :drugless healing).). speed dPfofChiropractic regulated by exclusive auto -throttle rmfo (To be continued.) . g em'. he .TbTaomryou- theeldwiopenfwdeé Ìtwill rperattehelectric light plant, pump water,t, Learn at Home xpe ré,;re N. churn em' freeeer, chop feed, operate amain. narator,, -anyone c easily learn by our complete phfled,illustrated YY nfact, itis the esetos forestry work.., Chipper cooled complete DANIELS NAMES course andcomplete set of free charts life -like colors. rend, for NAVAL ADVISORS. 5 Lesson Sections FREE abtorylo-gra4 oy $ ..aDlec to Write for free facts. to +r. Write (Continued from page 323.) est offer ever made. catalog. Illustrated Book Free Mr:. h°Do'°t'raóf Cbi R tie -tells all about Diseases and Chiro [ctreanent C. Be nninghofen a Sons of Aeronautic Engi- know this Dept. 110, Hamilton, O. American Society proswperoous professe riite today bigfree4 offert limited. neers -Henry Alexander Wise Wood, New University, Dept. 440 162 N. Dearborn St. Cti-a -o. York City ; engineer and manufacturer of Special Dynamos student of naval for Arc Lamp in printing machinery and September0Morn Moving Picture aeronautics. Elmer Ambrose Sperry, Chi- WATCH FOB. Exactly like illustration. Shows. Special Dy- cago; Cornell, '76; founder of Sperry Elec- The latest fob out. Has bewitching little namos for Charging figure of Mlss "September Morn" handsome- Storage Batteries. tric Co. and designer of electric appliances Iy embossed on heavy metal plate. Beautiful Dynamos for for and aero- oxidized silver finish. Size of medal a% x Special and gyroscope stabilizer ships Ist. Genuine black leather strap. Bo a Incandescent Light- planes. real work of art. Classy. alluring. Rakes ing. We sell upon em ail take nodes. Agents wanted every- payments of $5 and where. Dandy sample fob and ur great $10 per month. WIRELESS STATION AT FT. easy money proposition to hustlers seat Hobart Bros. Co.,Troy, O Postpaid 25 cents. ADAMS, R. I. NOVEL JEWELRY CO. Plans for the erection of a high power 707 Lewis Block Buffalo. N. Y. $1.45 GIVEN AWAY -CUT THIS OUT wireless telegraph station at Ft. Adams $10. Six Volt CO Ampere Storage Bat- This is worth teries 40.95. have become known with the arrival of Special price $5.50 with this advertise- material for the plant. This station, it is TELEGRAPHY OPERATION ment only. $145 $18. Six Volt 80 Ampere Storage Bat- understood, will be the first of a projected Taught by retired railway olrnoer. Railway w' es in teries 58.95. Deduct $t.45 if you in- be- advanced rooms. Expenses earned. All graduates elude Advertisement with order. chain of towers for communication placed direct in the telegraph eervioe. Other types and elan from 79e. up. tween the principal army centers of the Send Sr Folders and Rates I° d stamp for out price lint. Don't pass it The covers coast. naval system already Pelaar School of Telegraphy, Madison, Wis. B v ay Electrical Novelty House cap -Cat it oat. Stores in N. 421 Broadway much of the coast line for that branch of America's Scientific Rnaaray Trainins8ehcol 824Bowery 129 St. the coast defense. You benefit by mentioning '"The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 365 UNIQUE ELECTRICAL SOLDERING IRON. The object of this new electric soldering iron is to form or generate heat directly at the point of contact, and only at the spot where the heat is needed for soldering Free! purposes, whether it be electric wires, armatures or cable work. Complete Set of You do not have to wait for the iron to Drawing Instruments get hot, as the instant the object to be - yes. I will give you this complete net soldered bridges the two carbon or car of drawing instrutments absolutely borundum high- resistance heating points free. They are regular working n- these points glow with a white heat directly struments-the kind I use myself and they do not cost you a penny. And besides the at the tips of the high- resistance material, instruments in this exquisite plush lined therefore conducting the heat directly to leather case I will give you absolutely spot needed. free a 20x2 inch drawing board, n 24 the inch T- square. a 12 in rule, a supply of When the object is soldered, the moment drawing paper, two triangles, n French the tool is taken from the work the current curve, pencils, erasers, thumb tacks, etc., etc. A complete draftsman's working ceases to flow, as the circuit between the outfit. And I give it to the men who get high -resistance points is opened; this cre- my personal instruction absolutely free. ates a great saving of current and also time. The iron is always ready for use. The high -resistance points will last indefinitely, and if they should become injured can be readily renewed, say the manufac- Be a Draftsman! turers. There is no loss of heat through conduc- tion or radiation, as will be found in the Draw $125.00 to $175.00 Per Month old -style electric soldering iron. It is used There is an urgent demand for skilled draftsmen. Companies are in conjunction with a small transformer, and will solder from the smallest to the issuing calls every day for men to fill positions paying from $125.00 largest work, depending upon the amount to $175.00 per month. Work is light, pleasant and profitable. of electrical energy that the iron and trans- Will Instruct Chief Draftsman You Personally I am Chief Draftsman of a large and well known firm. I have been doing Pay as You Wish! the highest paying expert drafting work for a qaarter of a century and I know the kind of training that is demanded from the men who get the l f men. big salaries. I will give you personal instruction deal individually with W kind Don't bother about the expense. you and give you up -to -date, practical working plans just as your ability 'chargeaverysmali tee for and advancement require. 1 train you by giving you actual work - training you to bean expe- practical work, the kind that you must be able to do in order to hold rienced draftsman.Youcan big paying positions. I will give you my indivdual instruction. pay the small cost as suits Ifpermanent.f your work is right, I will advance you rapidly. If it is wrong, 1 will show you beet. My object Is to you where, and make you do it right, and do all I can to make an ex- develop expert draftsmen. you pert draftsman and deaig er in a short time. Write today without fail.

Send Coupon For Chief Draftsman Dobe Engineer's Equipment Co., Inc. My Big New Book Div. 3388 Chicago, Illinois Put your name and address on the free coupon or Without any obligation on me a letter or a post card and send it to me today. 1 whatsoever please mail your book New Electric Soldering Iron. will send you absolutely free and prepaid my new Successful Draftsmanship" and book "Successful Draftsmanship,' and the greet full particulars of your liberal "Per - it special offer that I am now making on which you sonal Instruction offer to a few former are constructed for. Where get the $15.0) Draftsmana Working Outfit abso- students. It is understood that I takes an ordinary electrical soldering iron lutely free. You assume no obligations of any am obligated in no way whatever. of the old style to solder a No. 14 wire kind in sending in the coupon. Get in line now for a big paying position. Getting the book and splice 10 seconds, this new iron will solder full particulars of the special offer is the first step. in from three to five sec- Name_ the same splice Chief Draftsman Dobe onds; in fact, any job can be soldered in Engineer's Equipment Co., Inc. less time with it than by any other means, Div. 3388 Chicago, Illinois whether it be a blow- torch, the old -style Address .._,. electric iron or acetylene gas generator. This iron is thoroughly covered by patents issued and pending in all principal Show Card Writers Earn $80.00 to $200 Meet Your Personal Needs and a new factory a If you want to spoolalize in some form of electrical countries of the world, Month -LEARN FREE education suited to your needs, for a longer or shorter is being built for the sole purpose of manu- time, there is one place giving you boundless - in Show Card Writing and Lettering tunity. High school not required for this work. Also, facturing this new electrical soldering iron. absolutely tree to introduce our usual courses to degrees. Open nearly all the year. colon, if you will purchase an assort- Start almost any time. Expert (sanity. Cost low ment of Alpha Colors to use while now. Write for information to practicing. Particulars for stamp. HIGHLAND PARK COLLEGE RUSSIAN COMPANY OF WIRELESS ALPHA COLOR COMPANY, Inc. Preeident, George P. Magill. A. M., D.D. TELEGRAPHS AND TELE- Dept. T, 81 E. 125th St., New York On Moines, Iowa PHONES. The annual general meeting of the Rus- sian Company of Wireless Telegraphs and Telephones (Russian Marconi Company) If You Are Willing To Pay was held in Petrograd on June 13, Vice - Admiral Bostrem, chairman of the board, A FAIR PRICE FOR THE BEST IN ITS LINE presiding. The directors' report and ac- BUY counts for the year ending Dec. 31, 1914, record a largely increased turnover in the business of the company, mainly due to MARS -BRIGHT orders received from the Russian Govern- GUARANTEED ment. The company declared a dividend in respect of the year 1914 at the rate of 15 FLASHLIGHT BATTERIES per cent., which was payable on July 13, OUR PRICE IS FAIR OUR BATTERY THE BEST BRIGHT STAR BATTERY CO. The retiring directors, Godfrey C. Isaacs YOPN. NY. and P. I. elected, NEW Balinsky, were re- and the BRIGHT STAR BATTERY New York MONTREAL. meeting passed a vote of thanks to Mr. CO., Balinsky and L. M. Eisenstein and their staff. You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com 366 THE ELECTRICAL EXPERIMENTER November, 1915 SquaroDeal AN ELECTRIC RANGE Miller FOR THE CHILDREN. Sys Playing "keeping house" has always been a favorite pastime with little girls. Just as the stove in mother's kitchen is

Your Washing Done for 2c. a Week u Waltham Electric or Water Power Will Do the Work Hamilton I have built a new "1900" power washing machine. I consider this machine the most won- al Howard derful washer ever put on the market. Built entirely of high quality sheet copper, it is the Elgin strongest and most durable machine made. It is constructed on a brand new principle and I Toy Electric Range. will guarantee that this machine will not tear Si Illinois- Rockford clothes, break buttons or tray the edges of the important in household work, so in play most delicate fabric. It will wash everything Al T 1 91 is from heavy blankets to the finest lace without 6 Models. the toy stove important to the miniature damage to the goods. I am the first man In the COUSIN) tooffer NO 52.75 mother, although these stoves have until the New 1910 Models of America's c n1NY `MON% This new "1900" washing machine can he con- best known watches. I have them Al, the present been only "make believes." nected with any electric socket instantly and is the latest products of the world' GIF SpKUT started and stopped by a "little twist of the most famous factories. You eon get =N^A1. Toys of the children are now being made wrist" and it will do your washing for 2 cents Gm, the latest mountings forDla mends and the most up-to -date Jewelry, at the rlghi price!. to follow advances in the home. A strik- a week. I also make a lighter power machine which ing example 's a miniature electric range can he run by water or electric power. On all No Money Down so devised that it is a practical little cooker. of these machines the .motor will run the wring- The range is 15 er too. Just feed in the clothes and this power Express Prepaid in Advance by Me inches in height and is wringer will squeeze the water out so quickly You take no chances with me. I am "Square Deal" Miller capable of cooking real food. It is equip- and easily you will he astonished. It will save and I trust the people. That is why 1 am doing the great- ped with an oven 4% inches wide and 5 50 per cent. time, money and labor every week. eat credit Watch. Diamond and Jewelry business In the The outfit consists of washer and wringer and ...NY. Suppose you want a watch. New 1010 inches deep -big enough to hold a little either electric or water motor, as you prefer, Model, a brand new up to date one. Name any one. I each. have It for you. No money down, Ewe.. prepaid. roasting pan. and I guarantee the perfect working of 1 on 30 days' tree trial. A full month to carry it in your pocket; and the easiest of On top of the range a be will send my machine Long Time Payments. That's the test that telle. all them kettle can You do not need to pay a penny until you are Watches Guaranteed tor 25 Years. placed, or food can be cooked in tiny uten- satisfied this washer will do what I say It will. sils that come with the range. A long cord Write today for illustrated catalog. Address: H. L. Barker, 0201 Court St., Binghamton, I Smash the Terms with plug is furnished to attach to any N. Y., or, if you live In Canada, write to the NO REFERENCES DEMANDED handy socket, and, best of all, there is a Canadian "1900" Washer Co., 355 Yonge St., My terms will surely suit you. You get unlimited credit, Toronto. Canada. with no red tape, notes or collectors cord switch, which controls the amount of An "Open Cdarre of Account electric heat sent to the range. Little girls the same kind of credit you get from your grocer. No fortunate enough to get a toy electric range matter where you live or what your income might he, you can now own the finest of watches, a beautiful diamond for Christmas will find "playing house" a or any rare jewelry and never miss the money. more fascinating pastime than they have 1916 Catalog FREE;^ yóam! ever before enjoyed. Li so can c and address t mail you tree and postpaid. the most rie beautiful catalog of its kind ever printed. I want you to have this book. It's a gem. It illustrates all makes of val- RAPID DETACHABLE ELECTRIC uable Watches, El Genuine Diamonds and a vast SEWING MACHINE MOTOR. assortment of Besutlfui Jewelry, all ou the easiest and Your Ho most liberal terms. Write for book today and get letter A quickly detachable electric motor for fro a that will make you my friend from the start. Deal MILLER, sewing machines has recently been put on IIni- Lectric lighting plant gen- Square Pres. erates standard llti -volt direct Milky- Hoefer Co., Miller Bldg., Detroit, Mich. current; operates from one to50 lights, electric motor, electric iron, vacuum cleaner, electric toaster, force pump, churn, washing machine, The Only Grand Prize etc. (Highest Award) given to No Batteries -No Switch -Board DICTIONARIES at t h e and a be machine for less money. Higb Panama -Pacific Exposition at c gornor.ve all competelm in one small. come was granted to pact unit. ie in staled rldependable. economical. Costs leas than other syst.ms to buy and WEBSTER'S to operate' Waterman Motor Company NEW 112 MT. ELLIOTT AVENUE INTERNATIONAL DETROIT, MICH. for Superiority of Educational Merit. It answers all Write to-day for kinds of puzzling Questions with final authority. full description ;Uni - LeGtri e' price. 60.50411.- ELECT MC u 100,000 Vocabulary Terms. New Gazetteer. and low LIGHTING SYSTEM 12,000 Biographical Entries. 2700 Pages. Over 6000 Illustrations. Colored Plates. Regular and India -Paper Editions Above: Not e Motor is n o t G. & C. screwed to ma- MERRIAM chine, but Is held COMPANY by friction. No Springfield, screws or bolts Mass. are used. Get the Best

Per Electrical Remingss.. RoyalsL. C, Smiths, Fox, Experimenter em.-Y r choice of any standard factory __ balltmachlnestsbarr ln. Everyone f ¡ L-i. perfeet,snd nteed forthree yeah smells owtopnews Meiraee1r- Please Send Sample Pages and Free Pocket Maps New Sewing Machine Motor. J,ti; f + mnt to Name. 80p camion1 each menhi °ar ddrese. the market, and is herewith shown. The Write for it. C. E. GAERTE, President motor is small and compact and supported IDEARBORN TYPEWRITER EXCHANGE. DEPT. 628, CHICAGO, ILLINOIS www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 367

on a special frame having four legs, on Here's YOUR Chance to Learn which two rubber plugs are set under each LET SAM BROWN leg to prevent scratching the woodwork of the machine. These serve also in keeping DRAFTING TEACH YOU THE the motor from moving around. The This Complete $15 Drawing motor is pivoted upon a shaft, upon which Outfit and Full Instructions In Mechanical Drawing a spring is so set that it forces the motor FREE AUTOMOBILE in an upward direction. .A small cork pulley is fastened onto the shaft of the prime mover. This pulley is used for driv- BUSINESS ing the hand -wheel of the sewing machine He'll fit you for a good job as chauffeur, test- as the photograph illustrates. The tension er, repair man, salesman, etc., in 3 to 5 weeks. Sam teaches you personally -is right on the of the spring keeps the friction wheel of job every minute. Established six years. the motor at a constant pressure against the hand -wheel of the machine, while the Earn $75 to $300 a Month rubber plugs under the feet keep it from Good Jobe everywhere are waiting for good men. moving around. In order to remove the Complete equipment to work on; 4, 6 and It motor it is only necessary to press it down cylinder cars for students' work. No theory. There's a good job waiting foryou. Bain is practical. Short on lectures-long on and pull it away. The motor runs both on actual, practical work. When you finish you alternating or direct current; it can also The country is facing greater are ready to tackle any auto problem. You're as good as the hest. Sam does a good jolt. run in either direction, just by remov- prosperity than Learn from a practical mechanic. I have a fine ing a screw and changing the position of it has everbefore 8 story building, at 1.513 -21 Prospect Ave., and the brushes on the commutator. A small 1620 -26 Browuwell Court. Welding and Bronz- experienced.Far- ing Depts.; large, weil equipped machine foot -operated rheostat is furnished with shop; Radiator, Fender and Tire Depts. Start this detachable motor, and this is depicted seeing men are In at once. Drop in and see me, or write -Sam Brown. in the second illustration. This device can getting ready for be used on any sewing machine, as there Ohio Auto School are no detachments nor screws needed for boom times. Get Dept. 211, 1521 Prospect Ave. installing the motor. this training now and share in the CLEVELAND, 0. VOICE CONTROLLER FOR - TOY ELECTRIC TRAINS. CHRLES W. MORE coming prosper PrealdentotmeCoueae ity The controlo phone is a Twentieth Cen- a d Heal of o hares Chic:,,;n We make Simply to Firm °f 21';,. al tury toy. talk it and you can .unl F.L< re sod the way plain. "A Million Volts start and stop your electric trains, motors, rnmra:an.Ceram. etc., and light and put out miniature electric lights at will. Through the Body" The controlophone will work on any Men Wanted The Secrets of Electricity AT BIG SALARIES in This is a rare chance for a few wide -awake young men. Stagecraft On account of the rapidly increasing demand for trained draftsmen Pres. Morey has issued Fully Ex- j orders that instructions be furnished to a limited number of young men who are inclined along engineering or architectural lines. posed Read about this great offer below-then mark and mail the coupon. Devote your spare STUDY AT HOME hours for a short time only and learn this profitable and pleasant Profession, and get in the class drawing the big pay envelope. Hundreds of men are in daily attendance at this old established college. In your own home you can do the same work these men are doing, and the same experts that teach them will guide you toward the big job. These well -known engineers prepare your instruction matter. Your work is examined and approved by them. They know exactly the practical training you need and they train you. No books to sell. Live, up -to -date blue prints of work in actual construction. In your own home you work with plans of machinery, buildings, steel works.etc., actually beingconstruct- ed in Chicago, New York and other large cities. High frequency Apparatus Voice Controller for Toy Railways. Electrical Drafting and Design Its and No other similar correspondence course in America has Construction voltage toy electric trains will run on, and a resident college of National reputation back of It, nor Practical Application a faculty of active experts actually enraged in muni- By Thomas Curtis it will also work on either alternating or cipal and corporation engineering work. These men Stanley know exactly the kind of [training you need bemuse direct current. they are in constant charge of Price $2.00 To operate this device by the voice, the big work. The most Comprehensive, Useful and Authoritative Work on this Subject Ever word which operates it must be empha- Offered, Send stamp for Circular. sized sharply, and it is best to make this $45 Y the last word of the sentence, so as to COURSE FREE A Few of the Subjects keep the instrument from repeating. Take IN MECHANICAL DRAWING Electricity In stagecraft -Electricity in hor- ticulture- Electra- Medical apparatus How the sentence "Start the TRA'IN." The This College has set aside a limited number of Free - Scholarships and will give the regular $45 Coarse to build the apparatus -How to perform word "TRAIN" must be pronounced Mechanical in of Drawing Free with any one of the Home hundreds experiments-How to use the sharply. Words like TRAIN-PLEASE Study Courses named in the coupon below -this is in X- Ray -Proportions for coils of various sizes addition to the complete $15 Drawing Outfit which is -Where to get materials and what they cost -TWENTY-QUICK, or ones which can also furnished to students free. Take advantage of this -How to teat and use the apparatus. be forced, are the best to use. unusually liberal offer today, as it will be withdrawn when the allotted number if Free Scholarships has Send your order to -day to After using the controlophone a short been awarded. It costs you nothing to get full information. TECHNICAL PRESS ASSOCIATION while, one acquires a code, whereby one No obligation on you. I t 6 -C Aeolian Hall - - - New York can work certain words into any sentence. ACT NOW -FILL OUT COUPON TODAY If the train is at a standstill, you can -Electrical Drafting - Builders' Conne say to the controlophone "Start the -Machine Drafting -Flan Reading -Architectural Drafting - Estimating TRAIN." This will put the mechanism -Structural Drafting -Sheet Metal Drafting into action and the train will start and -Civil Engineering (1060) - Surveying keep going until you say "Stop the Name TRAIN." It will then stop. Address ...... Diagrams for wiring are furnished by Town State or Home There ° over '° °rasa the manufacturers whereby you can say College Study Course Learn WirelessTelegraphy. R demand's for comp, tent operators -this profeemnn off en steady molt, (no matter where the train is) "Stop the At good salary-wt role. operators travel all overovver the world. CHICAGO The PAINE Uptown BUSINESS SCHOOL train at the station, PLEASE," and the TECHNICAL COLLEGE WI Broadway, (65th) New York. Send for Catalogue P. train will stop. 1080 LAKE VIEW BLDG. CHICAGO, ILL. You benefit iy mentioning "The Electrical E.rperimenter" when writing to advertisers. www.americanradiohistory.com 36S THE ELECTRICAL EXPERIMENTER November, 1915 BOOK REVIEW 11 Lessons of Course Craig's Q. & A. Book. (Questions and Answers about Electrical Apparatus). Tobacco Habit In Drugless Healing Revised, Third Edition. 1914, by James BANISHED in W. Craig and William P. Woodward. 48 to72 Hours _FREE! Flexible leather covers, 256 pages. 4% by 6a%4 inches. Pocket style. Profusely Positively and absolutely illustrated, $1.50. you! Not one cent Price Supplied by free to Electrical Review Publishing Co., Chi- to pay now or later. To No craving for tobacco in any form\ limited number and cago, Ill. immediately upon taking Tobacco Re- a deemer. Don't try to quit the tobacco for a short time only, The third edition greatly revised and habit unaided. It's a losing fight against we are giving brought up -to -date of this practical hand- heavy odds and means a serious shock to the 11 Complete book, written in question and answer form. nervous system. Let the tobacco habit Lessons in quit YOU. It will quit you. if you will Meehan This is one of the best books of its kind just take Tobacco Redeemer. according Therapy to be had and many valuable features are to directions. for two or three days. It is absolutely incorporated therein, such as the most marvelously quick and thorough- free. There illumination, ly reliable remedy for the tobacco babi; is no cost to D. C. and A. C. motors, transformers, 'the world has ever known. you at all for watt- meters, integrating watt -hour meters, these 11 complete lessons. But voltmeters and ammeters. Not a Substitute you must act Tobacco Redeemer is absolutely harm- quick) This re- Power factor meters, compensated volt- 1 less and contains no habit -forming drugs markable of- meters, etc., are covered. Not only are Iof any kind. It is in no sense a substitute fer is strictly limited Aé soon as a certain ordinary questions answered, but a host of for tobacco. After finishing the treatment number of these sets of 11 lessons have you have absolutely no tissire to use to- been given we shall withdraw the offer. extremely practical yet unusual ones, such bacco again or to continue the use of the Don't wait a minute. Act now. as, for instance, "Can D. C. of remedy. It quiets the nerves, and will a voltmeter make you fed better in every way. Itmakea not These Lessons Teach You the Weston type be connected up to an al- 'a particle of difference bow Lang you have been using tobacco, how much you slaeor in what form How to Treat Headache How to Treat Catarrh ternating current circuit ?" Such prob- you use it- whether you smoke cigars. cigarettes. How to Treat Neuralgia How to Treat Epilepsy lems as these and hundreds of others on pipe, chew plug or fine cutoruse snuff. Tobacco How to Treat Constipation How to Treat Hay Fever Redeemer will positively banish every trace of How to Treat Indigestion How to Treat Paralysis the commercial side of electrical matters desire in from 43 to 72 hours. This we absolutely a Sprain How to Treat Pleurisy guarantee in every case or money refunded. How to Treat are explained quite fully, so that the every- Write today for our free booklet showing the How to Treat Dyspepsia How to Treat Asthma deadly effect of tobacco upon the human system How to Treat Coot day electrician can grasp the underlying How to Treat Rheumatism and VV sitive proof that Tobacco Redeemer will How to Treat Lumbago How to Treat Jaundice principle easily and quickly. ' ly [free you of the habit. INEWELL PHARMACAL COMPANY Why We Make this Great Offer Dept. 521 St. Louis, Mo. We want the public to know the real truth Wireless Telegraphy. By A. B. Rolfe - about drugless healing. We want you to con- 1914. 256 Mil EMI MI ME MI Ell vince yourself by an actual and practical demon- Martin, B.Sc. Cloth covers, stration just what a marvelous curative force pages. 51/ x7l inches. 143 illustrations. may be placed at your command We want you ti I will send my 25c book';;: to see for yourself what tremendous opportun- Price $2. The Macmillan Co., New ities have been opened to practitioners of Me- IMPROVE YOUR' EYES hano- Therapy. You will see what has been York, N. Y. , For 10c, stamps or coin you done. You will see what can be done -by A A high -grade exercise and mas- A Diploma in Mechano -Therapy offers you a new volume in radiotelegraphic liter- profession of dignity, prestige, influence and ature which has many valuable points in it sage method that strengthens and wealth. No special training or experience needed. beautifies the eyes quickly. If you are ambitious and can read, the way to not commonly known to the average wire- +. 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Many of the features incorporated plete course of twenty -four have never been published before. The selected exercises for develop- New Illustrated Book ing all the muscles of the body. work starts with electromagnetic waves, It Is equal to any $.7.00 exer- on Drugless Healing FREE condensers, coupled circuits, syntonic de- ciser. My price for a short time Thousands of Mechano-Therapists throughout only, $1,00, the United States are making a big success. Let velopments to date, etc. Also damping or on tell you about them. Let us prove how you decrement is discussed and the calculations BARKER, can easily make $200 to $500 per month and more. Prof. ANTHONY llöw.i'sási.BOstiv:s Write while this special 11 free lessons offer is cited for this work in a thorough manner. open. 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J etc. Keehn, treasurer, and John Carlton, sta- Earn Big tion inspector. We believe that the office Money of "station inspector" is practically new All Branches of Art Tough BY MAtt. or tonal 0o you wane. ro KnoW, Classes. write for illustrated, booklet, terme] and list of among amateur, clubs. His duties are to successful pupils. inspect the stations of each member of HOW TO DEVELOP, Studios, 2130 N. Y. Associated Art Flatiron Bldg., the club at intervals of eight weeks and VITALITY, ENERGY, ENDURANCE: NERVE STRENGTH,MUSCULARSTRENG I to report the conditions and improvements PERFECT PHYSIQUE_ in same at the first meeting of the club LeatpyN SNpW CARDS My FREE BOOKS, 'The Whys' of Exercise"and'7he following his inspection. He also inspects First sad Laut Laws of ` and ill teach you Physical Culture," tell you, if you are personally by mail. the stations of persons applying for ad- weak or underdeveloped, how to grow strong; if strong, how Gl ' leyeses successful teach. mission and furnishes a complete descrip- to grow stronger. They explain how to develop lungs and Big field everywhere. muscle, the strong heart and vigorous dtaction -in shout, how 1 You can earn tion of such stations to the club. In case to improve health and strength internally ar well as externally. S18.Ó0 to $45.00 A WEEK the applicant is found ineligible, it is the Send TODAY -- NOW for these FREE BOOKS. Mr. Eckert. (Pa.) says tach lesson so inter- - esting eat " Postal brims duty of the station inspector to inform Enclose 4c. in stamps to cover postage. and news literature. DETROIT SCHOOL OF LETTERING him as to how he may fulfill the require- PROF. H. W. TITUS Chu. J. Strong. Founder Debt. 3711. Detroit, Mich ments of the club. 56 -58 Cooper Sq. Dept. Su New York City

You benefit by mentioning 11The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 369 WIRELESS TELEPHONY NOW FROM WASHINGTON TO HONOLULU. 1 (Continued from page 391.) sage was sent to Hawaii is greater than that between New York and London, New / York and Paris, greater even than from New York City to the North Pole! From New York to London is 3,740 miles; to Paris, 4,020; to Berlin, 4,385; to 1 Bremen, 4,235; to Antwerp, 4,000, and to the North Pole, 3,435 miles. Owing to the lack of adequate sending apparatus at Honolulu it was impossible to communicate back to Washington, but a cablegram announced the fact that the message had been received and distinctly heard. The account of the successful experiment was given out by James D. Ells- worth, of the American Telephone & Tele- graph Company. He said in part: "Wireless telephony from the Atlantic Can You Accept a Position seaboard to Hawaii, a distance of 4,600 miles, is an accomplished fact. By the $ special wireless telephone developments Paying 125 to $300 a Month? which have been made by the engineers of the American Telephone & Telegraph Com- AltE your services in demand today. have you the training pany and of the Western Electric Corn - that equips you to hold a position paying $125 to $300 a month? pany (which concern made all the appar- Have you the same knowledge as the man who gets the fat pay envelope? atus for this remarkable long distance It you are ambitious -send the coupon below and find out about the opportunities that await you test, including the vacuum tubes), speech in the profession of Signal Engineering. Salaries are paid to men who know. You can get just the kind of training you need to accept one of the big jobs. right in your own home -dnring your snare was transmitted from Washington to a time. We need men. Do not delay. Send the coupon today for the book that tells you all about it. wireless station near Honolulu. If anything further was needed to show the wonderful capacity of these new discoveries Be a Signal Engineer We Need Men Two Big Be the man who gets the fat pay envelope. The pro- The profession of Sigma] En- Outfits by the engineers of the Bell system, this f esaion of Signal Engineering is only in its in fancy. There gineering is calling to ambitious last triumph, coming but a few hours after are thousands of miles of block signals to be installed. men. Our ranks are not over- FREE Signal Engineers, supervisors, inspectors and foremen are crowded. There are opportu- Complete sig- Mr. Vail, the president of the company, y d to superintend this InWlalion. Hundreds of maintainers nitles- golden ones, awaiting nal Engineer's had talked by wireless from Washington and battery men are needed to maintain the system, already In use. the men who answer the call. Outfitandcom- Your duties may take you from coast to coast. Block signal systems are no long- piete Drafts - to Mr. Carty, its chief engineer, located at Railroad n are always in a fortunatepo 'lion to travel er in the experimental stage. All man's Outf it the free awarded. over the country they are being given away Mare Island, is conclusive. ôú sea pt épotion e °yó willbe localiberallydlly absolutely free if you prefer -the position of authority -the high place and installed. Some States have legis- "That transatlantic wireless telephone flace,'at Day envelope may be yours. Send coupon for free Signal Book. lated to compel the railroads to to our students systems immediately.mmediately. In communication is assured as soon as the our profession you will have the disturbed condition in Europe will permit to a Month chance you have been looking $125 $300 for. We are calling you. Take Department of tests from this country to there, is ob- That is an ordinary salary for Signalmen-many immediate advantage of this Signal Engineers make much more. ln the Signal Depart- wonderful opportunity. o f Signaling vious when it is remembered that all s, up rvisor,. Inspecter. maintainers. battery men, posi- Don't fail to send the cou- Room 3388 tions of authority i g f i75.ÓÓ a month up all open to the today our big scientists agree on the fact that it is much men who have has tb a d of training you rot right In vour eon for free Safo Wilson Avenue ownn home. Ë n while you learning You hold one of the Signal Book and full par- if Ravenswood Station more difficult to send wireless telephone in the Signal under a Signal Engineer. Oculars. Do it NOW. Chicago, Illinois communications across land than across Gentlemen: send water. This wireless telephone message Send Coupon for Big New Book e absolutely free and pre- from Washington to Hawaii had to pass , Signal Engineeering. A tao full Put your name and address on the coupon or on a letter great over the whole of the United States a post send us. specialp freeoaho t yomr1I -a card now. and it to Absolutely no obligations finely understood that I assume distance of 2,500 miles- before it en- of any kind. We will send you our big new Bonk absolutely free, no obligations of any kind. countered and prepaid. Read about this fascinating profession. Read better wireless conditions which about the opportunities that awaityou. The book is free. Send exist when sending over large bodies of the coupon for it now -it's the first step toward the realiza- Name water. For the purpose of this test the taon of your ambition.Get your name and address in at once. sending was done from the navy wireless Address station at Arlington, just outside of Wash- Department of Signaling Room3388,1810 Wilson Avenue, Ravenswood St lion, Chicago ington. The receiving was done on a small Age Oreupatioa wireless antenna specially erected for the BR purpose by the engineers of the telephone ATTACK NOW ANDU PREPARED company, which, by permission of the naval After my 27 years work for U S. and Foreign Governments and large authorities,' was corporations, 1 am in a position to offer you the cream of my lites located at the naval station ork, ¡w,h,i,ch comprises the Best Course Ever Publicly Offered In at Pearl Harbor. Hawaii. which embraces Projection. Developments. Intersections, Artistic Machine Deeieo. "The message at Honolulu was received Maelline Design Cam Charts. Real Shop Drawings, U. 8. by Lloyd Espenchied, and Foreign Patent Laws, Etc. NO LARGE FEE IN ADVANCE. an engineer of the PAY AS YOU LEARN. NOTHING FREE. Write for psrcieui m. American Telephone & Telegraph Com- ATTENTION Submarine "Technical Education" Preparing to RIVATE INSTRUCTION Engineer pany, who had been sent there by Mr. J. Attack the Obsolete Battleship "Ignorance" ERSIBTENT COACHING BY Consulting J. Carty, its chief engineer, to take charge PERSONALRACT ICAL ENGINEERS 10 Melts Bldg., Bridgeport. Ct. of the observations, the successful results of which we are now able to report. THE PANDICULATOR "Another interesting feature of the tests was that, in a practical way, the ability to connect wireless telephone systems with _= L11--11111 IJ U and WIRELESS wire telephone systems was shown. You have no doubt noted that Mr. Vail in his li¡¡ The confused condition of the corn- talk JI merciai world has created a vast in- used a wire circuit from New York crease in the use of wire and radio. We to Washington. At Washington, by the believe that students who start now will This University discovery is the most im- special means invented and developed by reap the advantages of great opportunity portant health invention of the century. It re- created by the war. makes and rejuvenates the Human Body. It the engineers of this company, the wires Send produces normal spines. It frees impinged and were connected to our special !if us 10c. (now) for our book on irritated nerves, corrects muscles, wireless ap- 'NI "Telegraphy and Wireless as an Oc- contracted paratus and to the navy's mighty wireless cupation." shortened ligaments; eliminates congestion, im- proves circulation and drainage of the body. IT tower, where the message went wirelessly WILL INCREASE THE BODY'S LENGTH. to its destination." The exact apparatus used in this pho- BOSTON SCHOOL OF TELEGRAPHY THE PANDICULATOR CO. nomenal test of the wireless telephone is 18 Boylston St., Boston, Mass. Cleveland, O. being kept a secret owing to patent reasons, You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com 1915 37o THE ELECTRICAL EXPERIMENTER November,

etc. However, it is understood that an audion type amplifying detector was used ABRAHAM LINCOLN J:a at the receiving end, which apparatus Ywil/ study and get boosts the strength of the received signal LEARN ready and maybe to a high degree. At the sending station a my chance swill come:' new form of vacuum trigger tube, devised by Dr. Langmuir and known as the Pliotron, played an important part. This eAlliO tube, of which 300 were used in a bank, was described in a previous issue of The Electrical Experimenter, and permits a `'$OSINESS large amount of energy to be controlled easily by a simple microphone of the type Earn a used on the standard telephone desk set. A distinct trigger control circuit enables Splendid Salary this to be accomplished in a simple and Over 3,000 graduates of our school are now YOUR Chance receiving big salaries as Chauffeurs, Testers, positive manner. Mechanical Experts, Demonstrators, etc., The following details of the apparatus etc. There are greater opportunities now Will Come used for transmitting wireless talk from than ever before in the auto business -for to Honolulu are given through properly trained men. a cabin, Arlington New 8 and Iz Cylinder Cars For You to Born in log Abraham the courtesy of Dr. Lee de Forest. The Work on. Lincoln had little chance to transmitting plant comprised 300 regenera- -to -Date Training in 4 Weeks tubes (each bulb measuring Up acquire an education. But tive vacuum Our school gives you the most modern 7 inches in diameter) and these were ex- and complete training, including expert in- he was determined to succeed. cited on 250 volts direct current. The struction on latest starting and lighting systems, newest types of motors, carburetors, "Some day," he said, "my bulbs were arranged on six panel boards, etc., etc. Repairing, overhauling and driving 50 to a panel. Each panel consumed 50 high- powered cars. Get the benefit of our chance will come." So he kilowatts, thus making a total of 300 kw. it years of experience and steadily increas- to ing success-we are the oldest school west studied and got ready. And of energy absorbed, and the net output of New York -the best equipped, the most the antenna was 70 kw. at 150 amperes. competent instructors. Tuition and board his chance DID come. bulb, in other words, produced 1/g reasonable. Each Come and see us now or send for free ampere of radio frequency current. The catalog. Your chance will come. Some trigger control grids of each bulb were of CLEVELAND AUTOMOBILE[SCHOOL day you'll be considered for connected to the secondary windings =343 Euclid Ave. Cleveland, Ohio. promotion or for a good job in small transformers, the primaries of which were hooked up in series with a suitable some other line of work. If battery and a microphonic transmitter. you are ready, you'll go up. Thus when transferring land -line talk (as from New York to Arlington) to the wire- And you CAN get ready. No less sending circuits the regular Bell tele- matter if your schooling was phone receiver at the other end was caused limited you do have to work to act on the microphone and the latter -if created the varying changes in the vacuum long hours. If you really want tube circuit, which variations in current a better job, the International were manifested finally in the antenna it- Correspondence Schools can self. The microphone had only to care for train you for it at home during a small current, or about 1/2 ampere, to be your time. exact. Thus the vacuum tube principle, Away spare highly developed and perfected by such in- 'Iota Throw defatigable workers as Prof. J. A. Fleming, More than Five Thousand I.C.S. Dr. de Forest, Dr. Langmuir, Messrs. Lie - Your Wornlires Students every year take the ben and Riez and others, has apparently You can get 5,000 miles MORE trouble to report promotions or solved the wireless telephone problem, service from them. salary increases due to I.C.S. help. which indeed had bid fair to baffle the For over three years European Motorists What the I.C.S. have done for scientific men of the old and new worlds have been getting from 10,000 to 15,000 for many years to come. miles out of their tires by "half -soling" them these men they can do for YOU. with Steel Studded Treads, just as we half -sole our shoes when the first sole gets thin. U. S. IS LACKING IN WAR WIRE- In the past 8 months over 20,000 American the Coupon NOW Motorists have followed their example and are Mark LESS, SAYS DE FOREST. saving $50.00 to $200.00 a year in tire expense. The American army is so poorly equipped Just mark the position or occupa- with wireless stations and facilities that it Guaranteed 5,000 Miles without' Puncture and mail in invasion, for an tion you prefer the would be easy, case of Absolute freedom from tire worry -blowouts, coupon today. Finding out costs enemy to cut the ordinary telegraph wires punctures, rimeuts and rutwear eliminated-no and completely isolate the East from the matter whether your tires are old or new you nothing. should put on Durable Treads at once -they West, Lee De Forest, the wireless inventor, cover your tires from rim to rim-nothing can said at a recent meeting of the American work in between -that's why we guarantee them Defense Society in New York City. as we do. International Correspondence Schools "The United States," he added, "urgently We Deliver Free- prepay the express and Box 1071 -T. Scranton, Pa. high -power radio stations allow you to be the judge. Durahle Treads Please explain, without ob !gating me. howl can qualify needs a chain of are easily applied in your own garage in 30 for the position, trade or profession before which i hay extending across the continent. One old minutes without extra tools. marked X. is binds us to telegraph cable all that Speci I Discount to motorists In new terri- ELECTRICAL ENG. MECHANICAL ENG. solutely indispensable, but the United tory on first shipment direct from the factory. Electric Lighting Mechanical Draftsman Mail the coupon today and we'll send you full Electrician Shop Practice would quickly be isolated. sample, and copy of signed guar- Interior Wiring Gas Engineer telegraphy is ab- information, Electric Car Running ARCHITECT "In aeroplaning, radio antee without any obligation to you. Telephone Engineer Builder & Contractor solutely indispensable, but the United Telegraph Engineer Structural Draftsman STEAM ENGINEER Plumbing and Heating States has almost no aeroplanes to equip. This Today Mining Engineer CIVIL ENGINEER But the navy is up to date in radio teleg- r-Mail Chemist Surveyor l COLORADO TIRE & LEATHER- CO. BOOKKEEPER Railroad Construction raphy." Higher Accounting CONCRETE ENG. 119 Tread Bldg., Denver, Colo. Shorthand &Typewrt'g Textile Manufacturing 1 Dept. K9, Box 228, Chicago, Good Eng. forEvr'yone ILLUSTRATOR PORTABLE ARMY WIRELESS 911 Woolworth Bldg., New York. CIVIL SERVICE Window Trimmer Railway Mail Clerk Show -Card Writer SENDS 44 MILES. Gentlemen: SALESMANSHIP Agriculture men at Fort Leavenworth record Please send me, without any ohllgatlon, full in- ADVERTISING AUTO. RUNNING Army formation, sample and copy of signed guarantee recently a record in having sent a wireless for 5,000 miles. Name message 44 miles, using the United States by Name Sired and No Army's newest field apparatus, operated the Fifth and Sixth divisions of Company Address City State Signal Corps. The older Occupation A, United States field radio machines seldom were capable 1 My Tire Sizes are Employed by of sending radiograms more than 35 miles. to advertisers. You benefit by mentioning "The Electrical Experimenter" when writing www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 371

' BARON MUNCHHAUSEN'S NEW did not appear to have much style. The When its ponderous portals, measuring at SCIENTIFIC ADVENTURES. upper part of the body was enclosed in a least 200 feet in height, had swung around (Continued from page 314.) sort of blouse like our young boys wear on so that they pointed in our direction, the Earth. The trousers looked like knickers, structure ceased revolving. Immediately the portals slid back and out stepped a scientific prophecy, obtained by cold rea- but went down to the ankles. "While we were still gazing enraptured distinguished looking Martian, taller even soning, reminded me of tLeverrier, the He was dressed like French astronomer, who by cold reason- at these strange marvelous beings, we sud- than his brothers. on Aug. 31, 1846, denly became conscious of our brains being them, the only difference being that his ing and mathematics in color. predicted the existence of a new planet, filled with a wonderful sort of music which metallic cap appeared yellow Neptune, which no one had ever seenef seemed to originate inside of our heads. Otherwise there seemed to be no differ- "The Martian I was gaping at, who was Instantly, the Martians who had stood ence in his attire. standing nearest to mc, was between eight around in a haphazard manner, formed a "At a gesture two Martians stepped for- and nine fcet tall, a veritable giant. He lane, the center of which was formed by ward to us and taking off our headgear had an immense head with a straight fore- ourselves. At the one end we now per- replaced them with the soft metallic caps. head at least seven inches high. His light ceived a colossal bewildering structure By this time the distinguished looking blue eyes were about two inches in diam- with a church -like appearance which Martian had come up close to us and stood eter and placed close together; moreover, seemed to turn around slowly on its axis. still, but five feet away. He next placed they had a marvelously intelligent, as well as keen look in them, impossible to describe. Their hypnotic gaze held one spellbound and seemed to go clear through you. "The long thin nose w a s enormous but harmonized well with the rest of the face; the complexion was somewhat brown. The large ears stood Electrically like it out straight and looked enormous oyster shells, with The applications of electricity are increasing the inside turned towards me. i3TJ every day. The man who has an exact knowledge of electrical However, what caught my eyc ?¡ science has ever growing opportunity for profit. Ten years ago at once, was the strange 'caps' i practically all machines in use were run by steam engine and countershaft. Statistics now show that most of the machines used are now operated by the all Martians wore. These caps electric drive. A generation ago gas was the only known means for lighting looked as if they were made and cooking. Now almost every modern house is lighted by electricity, and of a flexible metal and from electric cooking utensils are coming more and more in use. Even the steam I locomotive. that great achievement of the twentieth century, is being gradu- their back dangled what ally replaced by electric power. Whether it be for driving machines, for thought to be a flexible metal railway transportation, for lighting, for heating, for cooking, for a thousand necessities, the watchword of the age is ' Do It Electrically." wire. We were soon to know N,l V daily their purpose. "The chest or rather the torso of the Martian was sim- Hawkins Electrical Guides ply out of all proportions to the rest of the body. It was . enormous, and made him look Will Show You How strangely top heavy. His arms Electrical knowledge means money to you and these books will show appeared thin and emaciated. you how to get it. Hawkins Electrical Guides are the standard works on Electricity. They as did his limbs. His hands cover every single phase of the subject and they are written in a way you can understand. had each two thumbs and four The text matter is arranged in questions and answers, and contains several thousand illustrations. No more groping for a solution of your electrical problem. You find the answer at once, clearly and concisely. fingers, the extra thumb being between the thumb and index finger, as compared to the hu- A Most Complete Library of Electricity man hand. The hand itself 1 was very small; in fact, it at the Lowest Cost looked much like a woman's Look at the titles and convince on Earth. yourself that Hawkins Electrical Guides tell hand you everything you want to know in Electricity. "The feet were almost cir- They are a complete course in Electrical engin- 11/2 eering. written especially for the ambitious man cular in shape and at least who's training himself for ndvancemeat,for the foot in diameter. The base wide awake man who Is likely to be called in for work outside of his regular line. for the man who looked very much like an ele- needs at his elbow. for ready reference, an accu- although the ankle rate up-to -date work on electricity. An examin- phant's foot, ation of these books will convince you of their was rather small and graceful, value instantly. They cost $1 per volume. They big flat are a wonderful buy at this price. and they are as compared to the the beat electrical books at any price. Don't take foot. The outside of the Mar- our word for their merits. 1511 out the coupon today and the books will be sent you absolutely tian's dress glistened strange- FREE for ur own examination. You have ly in the sunlight, and I felt seven days full use before you pay a cent. sure that it must be made of wTihthe MN I= metal, unknown to In Handy Separate Volumes goldeidmhasste durableand attractver a flexible The books are easy to handle and easy to read. They fit your pocket and your pocket-hook as well. us. It fitted rather loosely and FREE 'tJean Joseph Leverrier, a French COUPON astronomer, on Aug. 81, 1846, in a to You FREE Polytechnique, Shipped paper to the Ecole Theo. Audel & Co. declared that he had computed the Send no money. Examine the books first. Decide for yourself that ; 72 Fifth Avenue orbit of a supposed new planet still they are the most complete library of electricity ever published. and that you cannot the afford to be without them. Every book is complete in itself. The price is only Si per co Y. NEW YORK further removed than Uranius, can be made at $1 be the last but the complete set is the best bargain. Settlement only per month. Please submit me for exam - latter then thought to NUMBERS ARE READY. planet in the solar system. Not only EIGHT uidesn Hawkins Electrical did Leverrier predict the new planet, Gone, $1 each). Ship but he also predicted it to be a star Easy Payment §' at once, prepaid, the first eight wolf AFEW OF THE SUBJECTS numbers; if satisfactory I agree to of the eighth magnitude. Most Magnetism-Induction-Experiments- Accept this great offer now- derful of all, however, he actually - ctrc Machinery-Motors-Armatures-Arm- today. Each page-every illustra- send you $1.00 each month until paid. ature W indi ngs-I nstalling of Dynamos- Electri- indicated where this new planet Instrument Testing- i'raebeal Management tion will convince you of the big should be located in the heavens, fI and Motors -Distribution Systems - value we are egerinF See the astronomers WDynamosiring -Wiring Diagrams -Sign Flashers -Stor- books first. then decide. If you Signature and he asked that Prince plea of Alternating Currents decide to keep them you can should look for it there. This iMaatteries-Alternators -Alternating Current Motors-. Tr make settlement at only $1 Galle of the Berlin Observatory did formers- Converters -R Alternat. monthly until paid for. ingCurrent Systems-Circuit Breakers-Measur- on Sept. 28, of the same year, and ingInstruments-Switch Boards- Wiring -Power Occupation Station, - Insttalling - Telephone - Telegraph - he found the new planet within less Wireless-Relle-loghting-Railways. Also many than 1° from the spot indicated by Applications Electricity ,na Mail Coupon® Leverrier, who had never seen the RReady dnefernc1 Reference 0 u Business Address planet himself. Leverrier had based Today his scientific prophecy upon certain 72 F ilth Avenue 1 Residence observed irregularities of the Planet THEO. AUDEL & CO. NEW YORK,N.Y. Uranius, although Neptune is 2,634,- 560,000 miles away from the Earth - an enormous distance.( Reference E.E. You by mentioning "The Electrical Experimenter" when 'writing to advertisers. benefit www.americanradiohistory.com 372 THE ELECTRICAL EXPERIMENTER November, 1915 (Continued from page 371.) the tips of the fingers of both hands to his temples, which we took to be a salute. We hastened to respond likewise, but we must have executed the motion poorly, for a faint rather amused smile ran over the brownish features of the august Martian. He then turned around and with a motion some attendants bade us to follow the chief, which we did. He then entered the church -like structure and we followed him deferentially. "Well, Aiier, my boy, I guess the telegraphone wire must be almost full by this time. So I guess I will have to close for to -day. Now don't forget to listen in to- morrow night for there's a lot to be said about this wonderful planet. Good -night * * s." Big Money A low rhythmic hum for a few seconds, then click, click -click, click- click-click, clink, a snapping sound and the ether between in the Moon and old mother Earth was un- disturbed once more. (To be continued.) Electricity THE N. Y. ELECTRICAL SCHOOL is the pioneer and premier school of the Learn by Doing" method. WIRELESS USED IN STARTING When you have completed this Course you shall he fully The electrical industries offer won- AUTO. qualified to handle ALL branches of Electrical i ndustry. The equipment of this School is unequalled and up-to-the- derful opportunities for boys with John Hays 'Hammond, Jr., has demon- minute.inute. No preparation needed to become a "learner" in strated that there is such a thing as wire- thin school. You start to team on any day of any a for week throughout the whole year. Send for catalogue. liking electricity. The sala- less control from land of an object at sea, ries paid to trained men are large but it has remained for the Overland com- New York Electrical School -promotion comes rapidly, and, pany to show that an automobile can be 29 West 17th Street New York City best of all, the profession is not started from a distance by means of wire- overcrowded. less telegraphy. Proof positive came at the Indiana State The opening of new lines, from Fair, where the motor of a Model 83 Over- We -4 Ir7 We Solely land was started every five minutes by a Guarantee Teach time to time, (such as wireless tel -. - wireless spark from the Overland head First Grade and egraphy and telephony), promise quarters, five miles away in Indianapolis. attractive and paying fields to those A complete wireless outfit -motor gen- Commercial z.s Specialize who wish to specialize. The will erator, transformers, relays and other para- Operators' 1 on Radio to do and Special Training will phernalia -was installed in the show win- Licenses Telegraphy dows of the city salesrooms. This was bring success to you. connected with an aerial on the roof of the building, and by stepping the alternating LEARN WIRELESS 'l'he International Correspondence current up from 110 volts to 16,000 volts Schools of Scranton can help to the apparatus made it possible to send mes- SEE THE WORLD make you an expert in electrical sages 300 miles: work. Hundreds of boys have The Overland car on exhibition at the AND fair grounds was fitted up with a receiving GET PAID FOR DOING IT already won success through apparatus and the necessary automatic I. C. S. help. You can do the switches and relays for throwing on and Last year every one of our graduates success- same. Everything is made so clear off the electric current of the starter and fully passed his required commercial Govern- that you can learn in your spare magneto. An automatic switch was regu- ment Examination upon the first trial. These results speak for themselves. Send a stamp for time, regardless of where you live lated so as to allow the car to run for 45 new fall prospectus Fall classes now forming. seconds, after which the magneto was cut or what you do. No books to off. The operation of starting the car was buy. repeated at intervals of five minutes. Eastern Radio Institute An interesting feature of the experiment 899 B. Boylston St., Boston, Mass. was the fact that the entire operation of There's big money in electricity. Get starting the car was accomplished without after it by marking and mailing the demand. The the aid of human hands. ELECTRICALmElectrical Sch0000 , attached coupon today. Finding out with its well -eoui costs you nothing. givee s ed course is Electrical STATEMENT OF THE OWNERSHIP, MAN- AGEMENT, CIRCULATION, ETC., ENGINEERING Mark the Coupon -NOW Required by the Act of August 24, 1912, litincluding Theoretical and Practical of THE ELECTRICAL EXPERIMENTER, published Electricity, in all branches. Student. Monthly at New York, N. Y., for Oct. 1, 1915: construct dynamos, install wiring and test efficiency of eleot rical ma- NAME OF POST -OFFICE ADDRESS. chinery. Course, with diploma, INTERNATIONAL CORRESPONDENCE SCHOOLS, Editor, H. Gernsback. .. 233 Fulton St., New York complete Managing Editor, H. Gernsback, I Box 1071e, SCRANTON, PA. I 233 Fulton St., New York Business Manager, M. IN ONE YEAR Explain, without obligation to me, how I can I Hymes, For practical young men with qualify for the position before which I mark X. 233 Fulton St., New York 2011 Men Trained limited time. 23rd year opens Sept. Publisher, Experimenter Publishing Co.,, Inc., 22nd. Write for new catalog E. Automobile Running 'Steno¢. &Typewrit'g 233 Fulton St., New York Special 6 months Evening Coure. in Motor Boat Running _.Bookkeeping Owners (if a corporation, give its name and the " Wire and Wireless Operating" Electrical Engin'er'g _ R. R. Accounting names and addresses of stockholders, holding one Electric Lighting ` Good English for Eryone per cent. or more of total amount of stock. If opens Novemhee 15th, 1915. An Electric Railways _ Civil Service not a corporation, give names and addresses of Exceptional Opportunity Dynamo Running Architecture individual owners): to qualify as a Telep. & Teleg. Eng. Contracting & Build. 1 Experimenter Pub. Co., Inc., First Class Operator 233 Commercial Mechanical Eng'r'g Structural Engin'g Fulton St., New York Write for catalog W. Mechanical Drafting _ Plumb'g & Heat'g N. Gernsback 233 Fulton St., New York Shop Practice Civil Engineering S. Gernsboek 233 Fulton St., New York 260 Takema Avenue, WASHINGTON, D.C. Steam Engineering Salesmanship :Milton Hymes 233 Fulton St., New York Mine Fore. & Supt. Advertising Known bondholders, mortgagees, and other securi- You May Learn Theory, Code an Chemistry Agriculture ty holders, holding one per cent. or more of total Laws of Radio Communlcatlon amount of bonds, mortgages, or other securities: In Our School or at Your Home, Name None. fitting you for position. paying good sal- H. Gernsback, Editor. aries with wonderful chance to travel the and No. (Signature of editor, publisher, business manager world over. Its the most interesting Pro- Street or owner.) fession known and the demand for skilled Sworn to and subscribed before me this 24th Operators is increasing. Send stamp for eat- 1 City State day of September, 1916. E. D. Junior, aloe wl ich gives fall information. Notary Public, Kings Co., No. 52. NATIONAL RADIO SCHOOL. USt) Certificate filed New York Co., No. 15. Washington, D. C. expires March 30, 1917.) L °= °Occupation ___ - -I.I I (My commission You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. www.americanradiohistory.com November, 1915 THE ELECTRICAL EXPERIMENTER 373

SOMETHING ABOUT SELENIUM. WHEN THE LIGHTS WENT OUT together, and the captain then hailed a ON THE "BELLA." passing tugboat. We dropped over the side (Continued from page 320.) of the "fruiter" down a rope on to the (Continued from Page 316.) tugboat's deck and shortly afterward were operating an automatic motor starter, glad to set our feet once more on terra our last visits to the ship, the whole bloom- which is connected to a motor driving a firma. No more hundred -legged, poison - ing bunch us were nearly shanghaied dynamo, supplying a bank of spouting centipedes for us. five -horsepower out port Love." This incandescent electric lamps. The mo- of the of "Brotherly of incident happened thusly: ment the cell is screened from the light All of the staff were down in the bowels NEW WIRELESS TO HONOLULU. the motor .is stopped, and if the light is of the ship busily engaged in clearing up The wireless station at the again allowed to fall upon the cell it com- Government grounds, our usual occupation, and the naval training at Lake Bluff, Ill., was pletes the circuit, consequently putting the station ship was supposed to leave the dock at placed in a severe motor and dynamo in operation. Thou- operation recently, after noon. At 10 p. m. a movement was notice- test which demonstrated that messages sands of horsepower of electrical energy able in the hold and at first this was not could be sent from there to Honolulu. The can thus be controlled just by a wave of paid any attention to. However, a little station is for the exclusive use of the the hand. later one of us ventured up to the deck United States Government and no commer- In Fig. 12 is illustrated a number of hatch and, "man alive!" we weren't cial messages be accepted. It be most interest`ng applications of the if will will scooting down the Delaware River as neat- utilized chiefly for the flashing of Govern- selenium cell (which were also shown at ly as you please, headed for the ocean. ment messages to the stations on the Pan- the aforesaid meeting) in conjunction Needless to say, it took about three shakes ama Canal and San Francisco for the di- with a battery and relay, used for starting of a lamb's tail to cover the time period rection of the Pacific fleet and for relay a tiny motor, ringing a bell, and stopping consumed in gathering our coats and tools to the Hawaiian Islands. firing a cannon, blowing a horn and lighting incandescent lamps. In the early nineties Mr. Hammer designed a dirigible torpedo, which he has long ago described in several of his lectures on the selenium cell. The identical plan has recently been proposed by several parties for steering an "electric dog," etc. Mr. Hammer's device consisted of an arm protruding from each side of the torpedo, edt[ i n;l each arm carrying a selenium cell her- GENUINE 11 Á'Y ana' Seconds 190 metically sealed inside a box and having a From Factory Direct To YOU By Ex or Pared Post Prepaid lens covering an opening in the rear, so Made of Imported limns. Picadura, from our own plantations in Cuba - leaves that are too short to roll into our high -priced Cgars. 'they're not pretty. no bands or decorations, but you don't that a searchlight of the vessel dispatching smoke looks. Customers call them "Diamonds in the Rough." All 4'S inches long. Only 100 at the torpedo could be thrown on the cell this "Oct Acaaainted" price. Money cheerfully refunded if you don't receive at least double value. In ordering mention mild, medium or strong. Our references, Dun or Bradstreet's or any Bank. to the right or the one to the left, thus To each purchaser of 100 Edwin s Genuine Seconds, we wilt for Soc extra. send Edwin's each of Bargain steering the torpedo to the right or to the Dr5e1.. onEooSI7.0containing1. Icrlode thiisein'your fit stthe biggest esamplevlalue ver offered. left, so that it would attack the flagship Nat/ - which was constantly being blanketed by -EDWINCIGAICÓ DeptN° Tí iIRDÁrLNEwYoRK the other moving vessels of the fleet. The Wherein New My* SAYEMOWEY9j338.134Z byPa4emzar +rryoflh!-/OOEOiY/NRetar/ - selenium cells were connected to a dif- ferentially wound relay connected with solenoids and a suitable battery, which turned the rudder and controlled the course or direction of the torpedo. The searchlight upon the enemy's vessels could not affect the selenium cells, as they would be exposed only at the rear of the containing boxes and would face directly toward the vessel dispatching the torpedo. The control of a torpedo could be maintained at a far longer distance with suc- Will you take a 20 lesson Wireless Course ab- cess by means of a searchlght and selenium solutely FREE -even postage charge prepaid ? be practicable by a tor- cells than would Just as you there would A course that tells you everything you can possibly pedo controlled by wireless; will receive it, want to know about "Wireless " Martine off in Leeson No. less chance of interference and it I by explaining the Principles of Electricity. The Second also be cloth bound, and Third Lessons are devoted to magnetism. motore; be more reliable, efficient and generators and wiring. And then, by simple easy stage. would far size 7 x 10% some years ago this wonderful Course takes you into "Wireless." The economical. Mr. Hammer ins., 160 pages, mysteries of "Wireless'' are unfolded to you by the use of this method of control for such simple language so skillfully used. that of necessity also proposed 20 lessons, 350 you must understand ery word. The subject is not and dropping o is whole a dirigible aerial torpedo for illus., 30 tables, treated superficially, bo wever, for there by means devoted to Theory bombs therefrom, releasing them with every bit of marking subject lend charm tothe Course, the last of the beam from a searchlight. Lesson (No. 20) is devoted to a history of Wireless and the for information on men who developed it. The wireless positively A number of ingenious methods Wireless you can cannot be bought. but will be sentnt absolutely with seeing at a full year's subscription (12 numbers) of the Electrical utilizing the selenium cell for possibly want, be- Experimenter at $1.00. It's the biggest dollar's worth distance have been proposed, but none you can ever buy nywbere at any time. Send for it sides valuable in- to-day enclosing 81.00. Send now before you forget. have as yet been worked out commercially. formation on Elec- The coupon below is a convenient way. But do it Selenium will undoubtedly play a very im- tricity, Magnetism now. some the coming dis- portant part in of and Theory of them THE EXPERIMENTER PUB. CO.. Inc. coveries and inventions. -and it's FREE as Publisher We are indebted to William J. Hammer, explained. "The Electrical Experimenter Magazine." consulting electrical engineer, of New York City, for permission to utilize in this article certain copyrighted illustrations and descriptive matter taken from EXPERIMENTER PUB. CO., 233 Fulton St., New York his book, "Radium, Phosphorescence. Gentlemen: Fluorescence, Selenium, Ultra- Violet Light, etc." On your absolute guarantee that your 20 Lesson Wireless Course is just as described by you, you may send me same FREE. You are to. send me this Course at once, all charges paid, and enter my name for a full year's subscription to the LEXINGTON, KY., NATIONAL Electrical Experimenter, 12 numbers, for which I enclose *$1.00, the price of the GUARD GET WIRELESSS Electrical Experimenter alone. EQUIPMENT. (If a 2 -year subscription is desired, enclose $2.00.) Part of the equipment for the wireless My name is station of the Kentucky National Guard arrived in Lexington recently. The plant My address is will be erected on the Fayette National *Canada and Foreign Countries, $1.25 -2 years, $2.50. Bank building and is expected to have a range of 2,000 miles. www.americanradiohistory.comr I Ra.rin,.n.be wh.,u a.,vil:en /0 ahlrrticorr 374 THE ELECTRICAL EXPERIMENTER November, 1915

RADIO FREQUENCY CHANGERS. 3 per cent. the amplitude of the current in Of special interest was the paper on the secondary would drop to 25 per cent. of "Frequency Changers" read by Prof. J. its maximum value. Zenneck, of Germany, at the September An interesting point brought out in the meeting of the Institute of Radio Engineers, discussion on this paper was the effect of STOP! held at Columbia University, New York eddy currents and hysteresis. The former We hereby present one of the greatest City. were 'dropped from the calculations for by bargaine ever offered in electrical literature. This is one of the latest developments in proper construction of the cores they would A complete volume of the Electrical Ex- wireless telegraphy and one that may revo- be reduced to a very small value. The ef- perimenter, bound in rich, dark green linen, lutionize our present methods of obtaining fect of hysteresis was merely to increase stamped with gold letters at the extraordi- radio frequency currents of large power. the resistance in the primary circuit and nary low price of in practise. The apparatus, as explained by Professor did not effect results actual Zenneck, consists of two closed core transformers as shown in the figure. The primaries of the transformers Pi and Pr, are energized by an alternator A. The winding B, and B_ are fed from a direct current source B and included in the circuit is a THE coil L,, possessing a sufficiently high inductance to prevent any induced A:C. from ELECTRICAL EXPERIMENTER flowing in this circuit. - 1915 It is important that the corresponding VOL.2 1914 75c. windings on these transformers have exactly the same number of turns and that the cores be exactly alike in all points of construction. The alternator supplies a current of 500 volts at a frequency of 10,200 cycles and the primary circuit is tuned to this frequency by means of inductance Lp and Cp. Volume contains twelve numbers, 240 The core is magnetized to 1/2 of its max- pages, 350 complete articles, 550 illustra- imum flux density by means of the direct tions, 396 questions and answers. current winding. The A.C. to A world of electrical information; the serves bring entire electrical Progress for one year; this up to magnetic saturation point. the greatest reference book on current Under the above conditions the A:C. flux "Wireless"-all at a price as low as the unbound copies would bring. Mind you, is superimposed on that due to the D.C. the book is durably bound with heavy and the resulting current induced in the covers. You will be proud to have it in Frequency Changer, Using Transformers Spe- your library. We have only a few hundred secondary has a higher frequency than the cially Arranged. copies, therefore be sure and order to -day. primary because of its peculiar wave farm. Shipping weight 2 lbs. Add a sufficient He showed that if the secondary wind- amount for postage. ings are connected in series to oppose each SEATTLE, WASH., RADIO TO BE other, the frequency resulting will be three EXTENDED. Experimenter Pub. Co., Inc. times that of the alternator. This circuit BOOK DEPARTMENT Port Warden A. A. Paysee, at Seattle, is tuned by means of a capacity Cs and an Wash., has requested Mayor Gill to allow 233 Fulton Street, New York inductance Ls. him a general public service license for the Going one step further, the effects of harbor department wireless, established re- NEW YORK CITY RADIO CLUB. connecting the transformers in parallel is cently at the port warden's office at Pier 1. The Clarkson Radio Club, of New York to obtain a frequency just double that in At present the station holds what is kn: wn City, wants for new members persons who the exciting circuit. as a limited commercial license, and the are interested in wireless telegraphy and For satisfactory results, it is absolutely local office of a steamship company is not who seek to advance this science. For necessary to keep the alternator voltage permitted to send messages to one of its further particulars address Geo. A.. Braca- constant after once adjusting the circuit to incoming ships. A general service license lone, Sec'y and Treas., 314 East 24th resonance. The speaker showed by graphic would allow the station to accept all such street, New York City. curves, that if the primary was de-tuned messages.

, Scientific Exchange Columns UNDOUBTEDLY you have at the present time some things for which you have no further use. Do you wish to sell these things or exchange them for something, for which you have immediate use? There is no surer and quicker way to do this than by advertising your articles in these columns. The Very people, the Only people, who could possibly have a use for your things read this journal. More than 40,000 interested people will see your ad. It is furthermore the cheapest advertising medium for you in the country. Dealers' advertising accepted in Opportunity Exchange Columns only. The rates are: One cent per word (name and address to be counted) minimum space 3 lines. Count about 7 words to the line. Remittance must accompany all orders. We reserve to ourselves the right to refuse any advertisement which we consider misleading or objectionable. Advertisements for the December issue should reach us not later than November 5th. The Classified Columns of "The Electrical Experimenter" Bring Positive Results.

jtl/ . Colt SALE- f.rnsl ark intrrrrgrter. This instrument, offers. C. O. Iiterholzer, 224 Seeley St., single -phase Wagner motor. John B. Hanley, 912 ment Is in good conditlop, having been used very Brooklyn, N. Y. College Ave., Ft. Worth, Tex. little. Two extra rods given free with it. Write FOR SALE-Loose coupler, $9; +/ K. W. trans- FOR EXCHANGE-One 110 -volt D. C. motor, one for particulars to Robert Zimmers, 2822 Broad Ave.. former coil, $4; Va K. W. condenser, $4; helix, 220 D. C. motor and small receiving transformer. Altoona, Pa. $1.50; electrolytic interrupter, $1.50; rotary gap Want 3,000 -ohm 'phones, navy One receiving transformer, Ferran FOR SALE cheap, the following: Eleetrese in- (battery). 15; Stationary gap, $1; energy indicator, and silicon detectors. George Evans, sulators, 2,000 -ohm 'phones, variable condenser, $1. All highly efficient. Luther Reiner, Dexieg, O. Tippecanoe City, O. Redioson, motorcycle lamp, switches, loading coil, FOR SALE -Football, 50e.; Remington single shot FIRST remittance of $10 takes almost new Colt new aerial wire, Murdock series transmitting con- 22, $3.50; 144 H. P. steam engine and bicycle. 22 repeating ride. 4 magnet generator, exchange denser and other wireless instruments. All cor- Write Raymond Bender, 147 S. Broad St., Waynes- for rotary variable or good 54 -Inch coil, Amco $4 respondence answered. John A. Irvine, Cannelton, boro, Pa. loose coupler $3. Paul Notestein, Wooster, O. Ind. FOR EXCHANGE -Type E $150 Marconi receiv- to ing cabinet complete, also 1 K. W. high voltage FOR SALE -Small generator, direct connected FOR SALE OR EXCHANGE-Mandolin, guitar. transformer for complete or part of radio receiving water motor. Generates 30 volts. Will swap. What Winchester 22, 1890 model repeater rifle, Korona 11, have you? J. Foraht, Box 861, Lock Haven, Pa. 4x5 plate camera and outfit, small lathe, bayonets, set or ClappEastham set of equal value or audlon breech loading small caliber Belgian shotgun, amplifier. John B. Hanley, Jr., 912 College Ave., FOR SALE-Complete set of receiving instru- dynamo meter for testing strength of back and Ft. Worth, Tex. ments: never been used and not borne -made. Sell lega, band grip dynamometer: want screw cutting FOR SALE -2002 -M. F. telephone condensers in at half price. For particulars write to Walter Met- lathe, 110 -volt A. C. motor, bicycle motor attach- tin boxes at 35c. each, also 15 H. P. 220 -volt A. C. calf, Lansing, Iowa. }'os h enfit bv "eatin" www.americanradiohistory.com^Tira Flerlrinl November; 19[5 THE ELECTRICAL EXPERIMENTER 375

FOR SALE -Banjo. No. 0 Brownie camera, Morse FOR SALE OR EXCHANGE -One 4x5 folding Seneca Ilke to exchange for telegraph outfit, wireless receiving apparatus, motor 11111111111111111111111111111111111111111111111IIIIIIIIINIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIII II1111111111111 plate Camera. Would and a number of story books. Send for list. Leland a good K. W. Transformer Coll of reliable make. / Slauson, Monticello, la. Epps, Oneonta, N. Y., R. No. 3. it Pays to Read These Columns Winfred kodak FOR EXCHANGE-1%-inch Spark coil 2O.ohni WILL exchange for a large Eastman 209 N. 3d Street, Charleston, Mo. sounder and key, telephones, polishing beard, emery, with supplies, 5x8 -Inch printing press and type, or huffing wheels, etc. Vest pocket Eastman Kodak. blacksmith tools, the following: 1 34 -itch auto Gentlemen:- receiving in- coil, $5.50; K. W. oscillation transformer, other electrical apparatus. Want y . It may be of interest to you to struments, or what have you? E. G. McCown, $6.50; 334 to 5 K. W. E. I. Co. spark gap $3.00;' home-made sending condenser, size 5x7 inch, know that I am now installing 21/z Spencer, la. value $3; one 3,600 -meter receiving transformer, Kw. station at half price; about 4, 12 Specialty Co. loading coil, 750 FOR SALE, CHEAP-I Omnigraph No. factory $10; $25. This certainly proves the dials, auto spark coil, telegraph instructor. Write meters, cost $4.50; E. I. Co. circular potentiometer, Oscar Belmont, la. $2; E. I. Co. peroxide of lead detector, $1.25; E. 1. worth of your paper; I would not for prices. Eliason, Co. electrolytic detector, $1.25; AMCo. Universal be without it. Two issues of it FOG SALE -$35 Gents' Coaster Brake Bicycle, detector with alloy and galena, $2; book on wire- like new, sacrifice, $15. Alfred Theis, 512 E. 88th less cost, $2.50. All letters answered. Albert L. have saved me $24.80. St., New York, N. Y. Hoydar, Fairfield, Neb. Myers. (Signed) tide' FOR SALE -Ducks new 1915 Detector with sill - my high grade 2-inch spark enn, I now rotary spark gap, never been used. All WILL exchange extra for $5 cash. M. H. Baldwinsville, N. Y. coil, which cost $11 wholesale, for a 110 -volt rotary Chapman, IiII IIIIIINIIIIIIIIIIIIIIIIIIIIIII illllllll 1111111111111111111111111111111 1111111 11111111 1111111111 Illllllllfllml,, spark gap of standard make and in fine condition. A COMBINATION 4x5 or 5x8 Plate Camera Will sell 110 -volt motor, $3; peroxide of lead de- (Tripod), one French and one Morrison wide angle tector, $1; telegraph key, 50e.; 9 wet coils. $1; lens (each cost $25), plate holders, carrying cases, home -made electrolytic rectifier, 3 -jar, $1; spark etc.. a bargain. W. E. Day, Pittsfield, Mass. gap, 40e.; Willard hydrometef syringe, 75e.: Little INTERFERENCE Preventer by A. L. Patstone. Hustler motor, 50e. All in good condition. I might Reliable receiving instrument for aerials of not less A POWERFUL Oxy -Ilyd. dissolving view Stere- use a coherer and relay. Duncan Thomson, 318 than about 100 feet length. thoroughly rubber in- opticon Outfit capable of making a 40 -foot picture, Miles Ave., Billings, Mont. sulated, to exchange for andion set of no less value complete with lecture sets and large assortment of than $25, or what bave you? Instrument rated to colored dissolving views. A rare chance to get a be worth $50 to $CA. E. B. Nattenbeimer, 555 Lex- LARGE outfit at SMALL price. W. E. Day, Pitts- PHONOGRAPH In good condition, 40 records, and ington Ave., Newport, Ky. field, Mass. Premo camera No. 0, will sell to highest bidder or for wireless goods. What have you? Karl Barnlag, FOR SALE OR EXCHANGE -75 -Ohm receiver, 428 E. Leonard St., Grand Rapids, Mich. FOR SALE OR EXCIIANGE -Electro's No. 9235 corn rond headband, Vi-inch Rbumkorff coil, new Detector, No. 8271 Helix, No. 9260 Condenser, No. electrolytic detector, galena detector, spark gap and All instruments MIGNON VARIO selective coupler, $4.25; Mur- 530 Condenser, 34 -inch Spark Coil. What have you? and Tesla shocking machine. in dock 1,000 -ohm single headset, $1.75. Francis l'ray, Deau Wilson, Alpha, III. fine condition. Benj. F. Kinnick, Jr., Greenwood, 102 Heath St., Somerville, Mass. Ind. Apparatus, FOR SALE OR EXCHANGE -Have full set I. C. FOR SALE -Experimenter's Electrical FOR SALE OR EXCIIANGE -Two E. I. Co. pro- hooks and tools. Want to buy Shaw bicycle motor 8. Complete Electrical Engineering, also Remington Okla, fessional type loose couplers, $5 each; pair Brandt% 22 15 -shot rifle (cost Both like new. attachment cheap. Alex. Serna, Lehigh, superior 'phones, t3.50: American model builder set, ga. $10.50). Want eudion detector or bulbs, variable condensers W. $4; one 234 -inch film tank, $2i one 4-volt 10 -ampere or 'phones of equal value. F. J. Scupholm, 939 WILL sell for $8 or exchange for / K. hour storage battery, $2: one % K. W. Packard Court St., Packard Transformer, a DeDion & Bouton motor- transformer, $7; Ferron detector, $4: Murdock sili- Pt. Huron, Mich. cycle engine complete with spark coil, mixing valve, con detector, with condenser, $4. Want I. C. S. spark plug and timer. Edw. W. McClure, 3325 or Minn. course in electrical engineering, andion detector EXCHANGE- Books, magazines, Shaw Engine, Hennepin Ave., Minneapolis, andion bulbs (good or broken). Henry W. Camp- motor, 38 bell, Ironton, O. etc., for most anything; want electric WOULD like to buy an " Omnigraph and records." reloading tools, or what have you? Box 322, Glas- Webber & Co., gow, Mo. Oliver W. Mathewson, care Paine, FOR SALE-1 K. W. wireless transformer with Boston, Mass. case, $15; 1 K. W. oil immersed $4; condenser, Transmitter, Giant Impedance coil, $1; 1 -inch transmitting set, $3; ex- FOR SALE OR EXCHANGE I. K. W. trans- AUTOMATIC Telegraph cellent portable receiving set, $12.50; coherer set, -A sounder and key, Civil Service Course, History of mitting complete, will send over 100 miles. Want Newspaper Correspond- $2.50; Standard resistance set and maul other $16 for set, which is in excellent condition. Will the Railway Mail Service, things at hargain prices. Write for particulars and ence Course, Insect Mount, Dividers. All for $2. sell part of set if desired. Cecil Bridges, Louis- Pa. complete list. Allen E. Dudley. Milford, Mass. ville, Ill. Mark S. Kistler, Centerport, cal. Colt's revolver in BOOKS 3c. each, such EXCHANGE- Police .32 as "Telegrapb Tom." good condition for a repeating rifle, camera, tele- "King of the Gridiron," etc. For large list write trope, blue rock trap, or anything useful. James Kenneth Woodward, 24 Lenox St., Uniontown, Pa. 11111111111111111111111111 J 1111111111111111111 111111111111 11111111 11111111 1111111111 1111111111111111111111 1111L Gallagher, 1246 Fulton St., Brooklyn, N. Y. FOR SALE -One complete I. C. S. electric light- WILL trade stamp collection 1,200 varieties, cata- ing course, four hound volumes, good as new, cost log value $60. for spark coil and other apparatus or $75; what offers/ Address John Stokes, 7305 Den - cash, amount depending on size and condition of niston Ave., Swissvale, Pa. coil. Make offer anyway. Howard Peacock, Barker, N. Y. WANTED -A second -hand induction motor of HE KNOWS! about y H. P., 110 volts, 60 cycles, must be in good DON'T STOP if you want to miss bargains. New condition. John A. Irvin, Cannelton, lad. wireless set, camera, motion picture films, mandolin, Rosser, Ilan. etc. Write for information. Kenneth Woodward. WILL sell E. I. transatlkntic 'phones, $2.50; 24 Lenox St., Uniontown, Pa. Mesco 2,000 -ohm 'phones. $3.25; engine coil, S2; Please make 3 more inser- Vesta" 6-80, $10. Carl Barnickol, 2317 Milwaukee FOR SALE -One National Automatic Telegraph Aye., Chicago, ill. Transmitter with key, sounder, 27 records, contain- tions of my ad. as per ening over 10.000 words and Dodge's telegraph in- HAVE 8 -volt 80 storage battery, coil condenser struetor. Outfit cost $20. Only 10 of the 27 rec- gap, key sends 12 miles. Nichols coupler, con- closed clipping. Results ords have been opened. Guaranteed as good as it densers, galena and Perron detectors, loading coil, was the day It left factory. Will take $10 cash. variometer, 2,000 -ohm 'phones, tunes 5,000 meters, I. A. Gibson, Jr., 403 Bolton St. E., Savannah, Ga. receives 1,600 miles. 110 -volt wireless telephone have more than exceeded transmitter, bicycle, skates, skees and pole. Want 8 -INCH spark coil, new, $50: 1% -inch coil, new, Crystaloi, large spark coil, 6-volt, 60 storage bat- my expectations. with spark gap and helix mounted, $5: sending out- tery, 3,000 -ohm 'phones, or what have you? Ira fit, 1' /, -inch coil high tension condenser, key, etc., Wright, Closson St., Methuen, Mass. $6: 800 mile receiving set, electrolytic detector, (Signed) J. L. GREEN. 1,000 -ohm bead set, fixed condenser, tuner, etc., $3. HAVE three 54-inch spark coils, loose coupler, Brand new 5x7 Premo Camera, tank, chemicals, variable condenser, loading coil; want Holtxer Cabot tripod, platebolders, etc., worth $45, price $30. I 'phones and crystaloi detector, or make offers. THERE'S A REASON. will buy or exchange for two to 20 pounds of Harold Baker, 134 N. Church St., Waynesboro, Pa. D. C. C. or D. S. C. 36 copper wire, having fairly gond insulation. Write Prof. Harry G. Starnes, FOR SALE-One K. W. Hightone cabinet type Hillsboro, Ind. rotary, $13; 1- K. W. Blitzen mounted transformer with protective device; $25; pair of Brandes navy WILL sell portable receiving set $5, cost $8; also 'phones, $10. Keane, 2936 Main St., Bridgeport, =,Id1 IIIIIIIIIU11111111111111u11111111111111111111111111111111 II1111111II IIIIIIIII IIIIII IIIIIIIIIIIIIIIIIl11i1111111111111ui0 :°: several different size magnets. Want 1 -inch spark Conn. coil, will pay cash. E. J. Bachman, 56 Fenwood Road, Roxbury, Mass. POR SALE OR EXCHANGE -1 pair of skees. No. WILL exchange or sell at a bargain. All articles good as new. Receiving Outfit, double FOR SALE -n/ K. W. $10 Packard transformer 2 Brownie camera, $2 tuning coil, y -iucb coil, ./- Interstate W. Helix, value $4; inch coil, static machine, boxing gloves, relay, two headset, static machine, X -ray outfit, 134 -inch send- in best of condition; one K. ing list. Mark Biser, Middle- spark gap, $2.50 platinum contact key, two con- flashlights, two small motors, master vibrator, $5 outfit, etc. Write for for worth 25e. books, town, Md. denser racks with plates and extra tinfoil. all of other electrical books. Want $11. Also 1,500 -mile range receiving sef at a rea- wireless goods, rotary gap, variable, transformer sonable price. Write me. Ellsworth Davis, Mor- 'phones, books, 22 repeater rifle, or offers. Write rice, Mich. L. H. Sargent, Abrams, Wis. FOR SALE -Edison Moving Picture Machine, 110 volts, 00 cycle, for the home, FOR - alternating current, FOR EXCHANGE -Bull's -eye kodak, 3? 4x3!4 pic- SALE -1,500 -ohm Murdock 'phone and head Y. M. A. A motion picture hand, $2. B. Stanley, 405 Jersey St., Buffalo, N. Y. school or C. combined tures, tennis racket, motion picture machine, 80C projecting machine and stereopticon, no toy. The feet film standard size, electric Miroscope, 100 views FOR SALE OR TRADE- 800-meter loading coil, film used is non -inflammable, 80 feet, contains as of Florida, unwritten on. Wireless apparatus galena detector, fixed and plate condensera, lightning many pictures as 1,000 feet of the film used in wanted. Russell H. Ford, 389 Tremont Ave., switch. Will trade whole for Brandes 'phones, or Nickelodeons, size of picture on screen at a dis- Orange, N. J. what bave you? B. Stanley, 405 Jersey St., Buffalo, tance of 30 feet 54x72 inches. Complete, including N. Y. transformer and curtain, no films. Guaranteed good I HAVE some electrical and sporting goods for as new, used only few times, cost $93.50, will sell sale or exchange. Write for information. Sherrill FOR SALE -New 2,500-meter for $58. For further description write H. H. Cupp, Llalbert, Terra Bella, Cal. loose coupler $6; 511 Anthony St., Carnegie, Pa. K. W. transformer, $8 (range 25 to 50 miles); 1 K. W. helix and gap with 7 radiators, $4. Instru- ONE "Search- Light" bicycle gas lamp and strong menta In good condition. Harry McCarthy, Ilnnt- two -bar magneto, all in gond condition, for 1 / or i ngdon, Pa. FOR SALE -$15 Murdock loose coupler, primary 2 -inch spark coil in good condition. Oliver Black, rewound with 140 turns and tapped to two 10 -point 19 Charles St., Lawrence, Mass. FOR SALE -Two 1 -inch spark coils, good as new. switches on bard rubber plate (photo), $20 value, each $2.50; electro adjustable sending condenser, $10. Eastman vest pocket camera with leather case, WANTED -3,000 -Ohm Receiver and Variable II1.75; electro Tesla transformer, $3. Great bargain, new, $5. Edwin L. Powell, 1206 E. Capitol St., Condenser. Must be in good condition. Write . C. Braatz, Lowellvilie, O. Washington. D. C. Joseph Kapinos, 115 Sweet Ave., Buffalo, N. Y. b-a- it b tneationin "Thewww.americanradiohistory.com Electrical Experimenter" when writi o advertisers. 376 THE ELECTRICAL EXPERIMENTER November, 1915 1

ELECTRICALS H.W. Westinghouse Alternator, account of illness of owner, will sell at bargain Junior" 2,000-ohm headset. In good condition. right for a small town plant, $300 in payments of price of $500; cost new, $3,200. 8. Gernsback, 817 Edmund Blum, 715 Spring St., Elgin, Ill. po per month. 18 H.W. 220 volt direct current West End Ave., New York City. generator will carry 900 regular 18 candle Tungsten EXCHANGE -Six -volt handdrive dynamo, good lamps. $200 in payments of $15 per month. lg FOR EXCHANGE slide trombone, condition. Want Crystalol, super-sensitive detector cells storage battery ln good condition $35. Elea. -One B fiat type AA. Clarence Vaughan, 175 Wickham Ave., brass, artist's model in good condition, cost $38, for Middletown, N. Y. Me Bath Cabinet $25. Box M, Troy, Ohio. eforest audion detector set, type R,R.N. Frank Russell, Newfane, N. Y. FOR SALE -Willard storage battery used five EXCHANGE-20-ohm sounder and key. Want f- months. Perfect Condition. Just the thing for inch coil or 2,000 -ohm headset. Harry Thomas, spark BARGAIN -Have several commercial transform- Mound City, Mo. - coils, motors, lights, etc. Cost $16, will sell ers. Like new. Transform 110 volts to 55 or 200. for $9. Donald Curran, 66 Thorp St., Binghamton, FOR SALE -Northern H. P. Multipolar motor, N. Y. Other taps may be easily taken out. Can he used 4 for making wireless transformers. Prices % K. W, D. C. 220 volts, with sliding base, $10. Roberts r%z $3, E. W. $4. Transformers only. No cases. H. P. motor, direct connected to 18 -ineh exhaust TWO rotary variable condensers, 33 plates, pair Robert Enders, 222 Britain Ave., Benton Harbor, fan, D. C. 110 volts, starting box for same, $15, 2,000 -ohm 'phones, factory -made loose coupler for Mich. D. C. volt meter $4, D. C. Ammeter $4, 4 -inch camera or offers. H. Butterworth, 15 Kosciusko dials, volt meter reads 0 to 150, Ammeter reads 0 St., Brooklyn, N. Y. SALE OR EXCHANGE -136 numbers of "New to 50. All are nearly new. Win. L. Leonard, 251 Tip Top Weekly" in excellent condition. Will sen Milwaukee Ave. E., Detroit, Mich. SALE OR EXCHANGE -Flashlights, three V,,- inch coils, % -Inch coil, loading coil, two 54-inch at Sc. each, or exchange for numbers of "Brave WANTED -To buy some good second -hand and Bold Library." Samuel Olnhausen, 824 Chester small secondaries, 54-inch secondary, primary condenser, Ave., vacuum and Geissler tubes, a X -ray tube for 3x10 tube wound 24 wire, 85-ohm telephone receiver, East Liverpool, O. experimental use. Francis Crump, de Columbus, polishing head and treadle, 50 porcelain insulators. Ind. two buzzers, heliograph, graphophone, 110 -volt FOR SALE - Several numbers "Electrical Experi- motor, bicycle, 15 -foot Old Towu canoe, three lazy menter," "World's Advance," "Modern Mechanics," HYTONE y, K. W. Clapp- Eastham set for aale. backs, camera, glass tubes, 2-bar telephone mag- "Popular Electricity and Modern Mechanics," one Practically new, includes key and hot wire meter. neto. All letters answered. Charles Long, Oak- Morgan's "Wireless Telegraph Construction for Write for photo and description. Price reasonable. mont, Pa. Amateurs" and three handbooks, all going cheap. Nelson Dunham, New Brunswick, N. J. If. Frankland, 517 W. 113th St., New York City, HAVE 1y, H. P. Thor motorcycle engine, Bb EXCHANGE-Small stock mall order goods worth cornet, will trade for complete wireless set or sell $16 for wireless receiving set. 630 WILL EXCHANGE- Manhattan No. 3 motor with Chas. Sehively, fan, good condition, for No. 2 Meccanb set. John separately. Write. Cloyce Rickey, Winfield, Iowa. Liberty Ave., Brooklyn, N. Y. Hamill, Sandwich, Ill. WANTED -One type SS dynamo motor, also want FOR SALE -A Baker electric coupe in first -class 1 -inch Bulldog spark coil. Will give cash; must be condition with new batteries; three passenger. On FOR SALE OR EXCHANGE-One "Electro in Al condition. Ross Durham, Bountiful, Utah.

Opportunity Exchange VOLT will probably find more opportunities and real bargains in these columns than anywhere else in the country. Most good things in life are hard to find and worth going after -these little ads illustrate that point; you alone will be the real loser if you don't take the time to scan through these columns. Advertisements in this section 4c. a word for each insertion. Count 7 words per line. 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 from above rate. Objectionable or misleading advertisements not accepted. Advettisetnents for the December issue should reach us not later than November 5th. EXPERIMENTER PUBLISHING CO., INC., 233 Fulton Street, New York, N. Y.

HAVE YOU SEEN A COPY T- Amateur Photo- BOOKS grapher's Weekly, $1 per year; weekly prize com- FORMULAS petitions; criticisms; print exchange; illustrated; AMMO many features. Three months' subscription 25e. Amateur Photographer's Weekly, 915 Schofield Bldg., HOW to Color Electric Lights inexpensively. In- Ohio. structions Dime. Jos. Diamond, 30 Ash St., Water- Cleveland, bury, Conn. ON APPROVAL MODELS OPPORTUNITY EXCHANGE-Any formula you want, 20e. Edwin Powell, 1206 E. Capitol St., Washington, D. C. YOU never would have believed, tell years ago, MODELS, dies and manufacturing for inventors that (lying in a sixty mile an hour gale were pos- by builders of "Tools That Work." La Croix Tool ELECTROPLATING -Plate your wireless instiv- sible -and yet this problem has been solved. Now, Co., 214 N. 21st St., St. Louis, Mo. ments and tools. Make money on silverware and it is the same with many other problems. For in- jewelry. Solutious ready for use sufficient for square stance, there are still millions of people who would GASOLINE and Steam Engines, 1 -10 to 10 H. P. foot plating. Nickel, 35e. Silver, 50e. Gold, $1. not have believed it possible to solve the following engine castings. Dynamos sud motors, 1 -30 H. P. G. Bowles, 1316 Gedden Ave., Aim Arbor, Mich. questions of ages: up. Complete electric light plants, $35. Send stamp for Bulletin 105. Dynamic Manufacturing Where does Power and Matter cone from? What Co.. National Bank Bldg., Chicago. is Power and Matter? Whv did it change into a First STAMPS AND COINS Universe? Why does the Ùniverse rotate? What DRAWINGS made for inventors. Consulting am 1? Why do I exist? What am I here for? Engineer, EE -3240 Seminary Ave., Chicago. STAMPS, 100, ALL DIFFERENT, FREE -Postage Why must we suffer so much? What becomes of 2e. Mention paper. Quaker Stamp Co., Toledo, Ohio. myself after death? Where am I going? Wbat becomes of my good and bad self? and why was MISCELLANEOUS every human heiug born with a tendency to good- WIRELESS ness and badness? Is there a self- evident answer THERE Is but one School to these questions? '1'he auswer is: That all these Telegraph that places all graduates direct in the Railway Telegraph serv- $10.00 Commercial Keys for $4. Money refunded questions and ninny more problems have been ice. It is Peinars, Madison, Wis. solved by self -evidence after many years of in- if not satisfied. Massie Wireless Telegraph Co., TT Washington St., Providence, R. I. r vestigation. If you are interested to &mow the $25 new Oxydonor for treating diseases for sale, results of thirty years' investigation on the lines $0, or will exchange of self -evidence by Erardus Sagra, the satisfaction for high grade 3,000-ohm head- NAVY type loose coupler $7.50. 3.000 meters set. John Mahlmeister, 49 Cedar St., Brooklyn, guarauteed wÿth Also con- of understanding yourself and your surroundings as N. 80 ft. aerial. detectors, well as the harmony between your own universal Y. densers, loaders. Send stamp for circular. Win. A. power and the universe Itself, will guide you in PHONOGRAPHS, any make, greatly improved in Lohr, 592 Miller Ave., Columbus, O. conjunction with Your Divine Power within you, musical tone; voices through the rest of your life like a truc friend in become humanized when using 2,500 -meter Loose Couplers, $5. Other wireless adversity the "RE- ANIMATER." Agents wanted who can bargains. Send for circulars. Cliff Mfg. Co., or prosperity. Now the author- investi- give all or part time. Address Ellis Mfg. Co., 410 Brookfield, Masa. gator, Erardus Sagra, did uothing but unveil, Jefferson St., Milwaukee, Wis. classify and state eternal plain facts (in con- 13 cents postpaid, book explains Arlington densed book -form and in plain, popular language), Weather Code Letters and figures. Also contains which so far not even the most learned and mat - PATENT ATTORNEYS secret amateur codes. John Mahlmeister, 49 Cedar ter -of -fact scientists could refute. St., Brooklyn, N. Y. An interested progressive reader says: You do PATENTS without advance attorney's fees. Not a not know how much help and satisfaction the re- RADIO queries answered fully and promptly, sults of your investigation gave me. due until patent allowed. Send sketch for free for 10e., 8 for 25e. J. L. Green, Radio Informa- Another reader said: Your production, report. Books free. Frank Fuller, Washington, tion Bureau, Rosser, Man. "The D. C. Might of Truth," is the most beautiful book I ever LOOSE- COUPLED receiving set; uses switch - read. DON'T LOSE YOUR RIGHTS to patent protec- points; wave length 5,000 meters; will receive Retail price, $1.00 net. Introduction, nominal tion. Before proceeding further send for our blank Arlington 1,000 miles. Price, $5. Information free. price during this mouth, 24 cents, postpaid to read- form, Evidence of Conception, to be signed and E. F. Ball & Co., Buckland, Coon. ers of the Electrical Experimenter. witnessed. Book, suggestions and advice free. Lan- 230 Money refunded if anyone can prove an untruth caster & Allwine, 242 Carey Bldg., Washington, SUPERFECT Aerial Masts, $50. Andion, $18. in this announcement. D. C. Stuyvesant Ave., Brooklyn, N. Y. Address M. T. Dept., Box 2034, Middle City PATENTS SECURED through $9 wireless receivers, $4.50 a pair. Rotary variable Station, Philadelphia, Pa. Credit System. Free condensers, the $5 kind, for $2.75. Circulars free. Search; Send Sketch. Booklet Free. Waters & Co., Brooklyn, 4287 Warder Bldg., Washington, D. C. Imperial Electric Co., 89 Wallabout St., N. Y., Dept. E. 360 POPULAR TOASTS-Selections suitable for PATENTS SECURED OR FEE RETURNED. FREE -1916 Wireless Calendar for 2e. stamp. all occasions; just what you need at an evening Send sketch or model for free search and report. "Arlington" tested Tuning coil, $3.50. Brass supper; 10e. Wedge Manufacturing Co., "KM.," Latest complete patent book free. George P. sliders, 25e. pair. Guaranteed. Lloyd Gress, PH' Binghamton, N. Y. Kimmel, 254 Barrister Bldg., Washington, D. O. man, N, J. www.americanradiohistory.com YOU MAY PAY MORE AND GET LESS. BUT -IF YOU ARE WISE -YOU WILL AT LEAST TRY THESE REMARKABLE NO. 55 MURDOCK RECEIVERS. OUR LIBERAL TRIAL OFFER AND OUR MONEY BACK GUARANTEE ASSURES YOUR SATISFACTION Complete Double 2000 Ohm Set only $4.00 Complete Double 3000 Ohm Set only $5.00 Either Set With Coronet With Regular Band. Band, $ .50 Additional With Coronet Band. FOURTEEN DAYS TRIAL ALLOWED Guaranteed equal in every essential to sets selling at many times the prices. Super- sensitive, well -balanced, comfortable, tested sets, which will work anywhere to the fullest efficiency. Order a set to -day. OUR CATALOG OF WORTH -WHILE APPARATUS WILL BE MAILED FREE ON REQUEST

680 HOWARD ST., SAN FRANCISCO, CAL. WM. J. MURDOCK CO., 55 Carter St., Chelsea, Mass.

Our New Big 216 PP. Electrical and Wireless EXPERIMENTER'S CATAL 0 G REENCE'S ;LEER BOOK

The Best Bargain The Amco Navy Type in This Magazine is Receiving Transformer

Represents the latest advances made towards the ideal tuner and embodies the greatest degree of perfection yet obtained. No greater value can be secured where accurate selectivity, sensitiveness and finish are desirable. The illustration shown herewith cannot possibly do justice to the instrument itself. The primary winding is enclosed in a cabinet, the sides and top of which are polished hard rubber. Two 15 -point switches are mounted on the front. One switch controls the primary in groups of several turns and the other controls one turn at a time. The entire variation of the primary is thus secured by the rotary motion of two knurled knobs rather than the movement of a slider, and may be varied from 1 to 225 turns in steps of one turn at a time. The windings are especially adapted to long wave lengths. The secondary is wound with green silk covered wire. The ends are HARD RUBBER, turned and polished. Secondary variation is secured by a 12-point switch which makes it possible to secure a very fine adjustment. PRICE, ONLY $15.00. SEND 6 CENTS FOR OUR CATALOG -DO IT TODAY -YOU NEED IT ARE YOU BUILDING SOMETHING? Out No. 6 CATALOG shows several hundred parts and sets of materials for building your own apparatus at home which have never before been listed. We do all the difficult work in our factory and then you put them together. WE HAVE JUST WHAT YOU HAVE BEEN LOOKING FOR Complete description and prices of the Latest Electrical and Experimental Apparatus -Storage Batteries, Rectifiers Transformers, Induction Coils, Wireless Apparatus, Lamps, Flashlights, Meters, XRays, Books, Tools, Electric Railways, Stearn Engines, Water Motors, Dynamos, Motors, Telegraphs. Telephones, Electrical Supplies, Model Aeroplanes and Parts for building your own apparatus. A Treatise on Wireless Telegraphy, telling bow to put up an aerial, connect apparatus, together with a Call List and Wiring Diagram, FREE with every catalog. Bc. in stamps will bring you this wonderful book. The best catalog of wireless apparatus, etc. published. ADAMS -MORGAN CO., 13 Alvin Place, UPPER MONTCLAIR, N. J.

, u hem., It Ir, cati, u, www.americanradiohistory.comHIr llrrhirnl Frgri,ui,nt." :6r+i vt1lu70